THIRTY-SEVENTH ANNUAL REPORT

OF THE

NATIONAL ADVISORY COMMITl!EE

FOR AERONAUTICS

1951

INCLUDING TECHNICAL REPORTS

NOS. 1003 tO 1058

UZWTEDSTATES

GOVERNMENTPRINTINGOE’HCEWASEIKGTON: 1952

!-e br the SuperintendentofD-eat& U.S. GmermuentPrintInzOEke,WaaMngton25,D. C. m $s.7s(BUckml)

Letter of Transmittal . , . .Letter of Submittal . . . . .Thirty-seventh Annual ReportPart I. TecbnicaI Activities .

Research Ormnization

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Aerodynamic;Research .Power Plants for AircraftAircraft Construction . .OperatingProblems . . ,

Part IL Committee Organization ,Pari HI. FinancialReport . , . .Technical Reports . . . . . . . .

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TECHNICAL REPORT’S

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1003. Correlation of Physioaf Properties tith MoleouhmStructure for Some Dic@ic Hydroetmbons Hati-ing High Thermal-Energy Release Per Unitl“ohune. By P. H. ‘Ji%er K. T. Serijan, and I. A.Goodm=, XACA ---------------------------

1004. A Lift-Cancellation Technique in Linearized Su-personic-WingTheo~. By Harold Mirde, XAC&

1005. Analyticrd Determination of CoupIed Bendfng-Torsion Vibrations of Cantilever Beams byMeam of Station Functions. By AIexanderMendekon and SelwTn Gencfler, NACA--: -----

1006. ArIaIysis of Thrust Augmentation of Turbojet En-gines by ‘i’iater Injection at Compressor Irdet.Including Charts for CaIcuIat ing CompressionProce.ses with Water Injection. By E. CIinton‘Tilcox and Arthur M. Trout, XACA- ---------

1007. Horizontal Tail Loads in Maneuvering Flight.By Henry A. Pearson, WUiam L McGowan,and James J. Donegan, h’A~A-----------__-_-

100S. A &nalt-Deflection Theo~ for Curved SandmichPlates. By Manuel Stein and J. Mayers.x.icA -------------------------------------

1009. Invest igation of Fretting by Microscopic Obser-}-ation. By Dougk Godfrey, x.AcA ---------

1010. A Recurrence Matriz Solution for the DynamicRe~po~e of &craft ~ Gusts. BY Jo~ c-Houbolt, XAC.1----------------------------

1011. Dynamk of a Turbojet Engine Considered ~~ aQuasi-Static System. By Edward IT. Otto andBurt L. Taylor, III, N.4C.l----------_--_-_--

1012. Investigation of the NACA 4-(5) (03)-03 audX.ICA 4+10) (0S)43 Two-BIade Propellers atForward Xach A-umbers to 0.725 to Determinethe Effects of Camber and Compre.wibiM y onPerformance. By James B. Delano, NAC.A-_

1013. Effects of Wing F1esibility and Variable Air LiftWing Bending Moments During Landing Imp-acts of a SmaII Seaplane. By Kenneth F.Merten and Edgar B. Beck, NACA -----------

1014. Study of Effects of Sweep on the FIut ter of Canti-lever Wn~. By J. G. Barmby, H. if. Cunning-ham, and I. E. Garrick, N’ACA--------------

1015. Analysis of Turbulent Free-Convection BoundaryLayer on Fiat P1ate. By E. R. G. Eckert andThomas W. Jackson. X.lC.L--_-_--_-_-------

1016. Effect of Tunnel Configuration and Testing Teeh-nique on Caacade Perfornuince. By ,John R.Erwin and James C. Emery, NACA -----------

1II17. Investigate ion of Frequency-Response C.haracter-istice of Engine Speed for a Typical Turbine-Propeller Engine. By Burt L. Ta3-lor, 111,and Frank L. Oppenheimer, X-ACA ___________

101S. A Theoretical kudysie of the Effect of Time Lag inan Automatic Stabilization System on theLater&f Osui.llatory Stability of an Airplane. Byl&onmd Sternfield and Ordway B. Gates, Jr.,K.AcA -------------------------------------

1019. Relation Between Inflammables and IgnitionSaurces in Aircraft Environments. By ‘iWfredE. Sclm, A-Ac.L ____________________________

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1020. Meawremente of Average Heat-Trru.wfer andFriation Coefficients for Subsonic Flow of Airin Smooth Tubes at High Surface and FluidTemperatures. By Leroy V. Humble, WarrenH. Lcmrdermilk, md Lelaud G. Desmon, XACA-

1021. Analysis of Phne-Pht io-i%ress ProbIems With.&&d Symmetry in Strain-Hrmdening Range.By M. H. Lee ~U, XACA_------------------

1022. Temperature Dish-iiution in Internally Heated‘TWs of Heat Exchangers Compoccd of Non-circuhm Flow Passages. By E. R. G. Eckert andGeorge M. IOw, NAC.L----_-_--------------

1023. Diffusion of Chromium in Alpha Cobalt-Chrom-ium Mid Solutions By John ‘T. Weeton,xAc.i -------------------------------------

1024. Ckdculation of the LateraI Control of SweptadUnswept Flexible Wngs of Arbitrary Stiffn=By Franklin W. Diederic~ XACA-------------

1025. Experimental and Theoretical Studies of &eaSuction for the Contrcd of the Laminar BoundaryLayer on an XAG.A 6MO1O AirfoiI. By AlbertL. BrasIow, DaIe L. Burrows, X-eal Tetervin, andfiorarate V&nti, NAC&---------------; --

1026. X-ACA Investigation of l?uel Performance inPiston-Type Engines. By Henry C. Barnett,xAcL ___________________________________

1027. Buckling of Thin-WaIIed Cylinder Cnder AxialCompression and Internal P-ure. By Hsu La,HaroId Crate, and Edward B. Schwartz, XAC.l--

1028. EHect of Aspect Ratio on the Air Forces andMoments of Harmonically Oscillating Thin Rec-tanguhw Wings in Supersonic Potentiat Flow.By Ckrl=E. Watti, NAC.A----------------

1029. Compressive Strength of Flanges. By Elbridge Z.StoweU, NAC.1-----------------------------

1030. Investigation of Separation of the TurbulentBoundary La}-er. By G. B. Schubauer andp. S. IiIebanoff, National Bureau of Standards---

1031. A study of the Use of Experimental StabiIityDerivatiws in the Calculation of the LatersJDisturbed Motions of a Swept-Wing .Mrplaneand Comparison With Flight Resuh By JohnD. Bird and Byron 31. Jaquet, NACA ----------

1032. A Comparison of Theory and Experiment forHigh-Speed Fr*MolecuIe Flow. By JacksonR. Staider, Glen Goodwin, and Marcus O.C-ger, XACA -----------------------------

1033. Comparison Between Theory and Experiment forWings at Supersonic Speeds. By ‘Walter G.Ybcenti, NACA ----------------------------

1034. Investigation of SpoiIer .liIerona for Use as SpeedBrakes or Glide-Path ControIs on Two NACA65 Series ‘i’i’ings Equipped ‘iVith FuU-SpanSIotted FIaps. By Jack FischeI and James M.Watson, NAC-4-----------------------------

KKi5. AnaIyEis of Metros of Improving the L’ncontroIldLateral Motions of Pemomd Airplanes. ByMtion O. McKinney, Jr., XACA--------------

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1046.

TECHNfCAL

Experimental Invwtigation of the Effects of Vie-cosity ou the Drag and Brwe Pressure of Bodiesof Revolution at a Mach Number of 1.5. ByDean R. Chapmrm and E&ward W. Perkins,NACA._--_. ---- _-_----- _------- _---- _----r

General Method and Thermodynamic Tables forComputation of Equilibrium Composition andTemperature of Chemical Reactions. By VearlN. Huff, Sanford Gordon, and Virgini& E.Morrell, NACA -----------------------------

Wind-Tunnel Investigation of Air Inlet and OutletOpenings on a Streamline Body. By John V.Becker, NACA ------------------------------

On the Particular Integrals of the Prandtl-Buse-mann Iteration Equations for the Flow of aCompressible Fluid. By Carl Kaplan, NACA. -

Spectra and Diffusion in a Round Turbulent Jet.By Stanley Corrsin and Mahinder S. Uberoi,Johns Hopkins Unive~ity --------------------

F~quations and Charts for the Rapid Estimation ofHinge-Moment and Effectiveness Parametersfor Trailing-Edge COLtrols Having Leading andTrailing Edges Swept Ahead of the Mach Lines.By Kennith L. Goin, NACA-------------.---_

Some l?ffec~ of Nonlinear Variation in the Direc-tional-stability and Damping-in-Yawing Deriv-ative on the Lateral Stability of an Airplane.By Leonard Sternfield, NACA----_-------_---

A hrumerical Method for the Stress Analysis ofStiffened-Shell Structures Under NonuniformTemperature Distributions. By Richard R.Heldenfels. NACA --------------------------

The Method of Characteristics for the Determina-tion of Supersonic Flow Over Bodies of Revolu-tion at Stnall Angles of Attack. By AntonioFerri, NACA -------------------------------

Supemonic Flow around Cirmdar Cones at Anglesof Attack. By Antonio Ferri, NACA--------_

A Generai Integral Form of the Boundary-Layer

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Equation for Incompressible Flow With anApplication ta the Calculation of the SeparationPoint of Turbulent Boundary Layers. By NealTetervin and Chia Chiao Lin, NACA------.--- 1067

1047. The StabiLity of the Comprwsion Cover of BoxBeams Stiffened by Posts. By Paul Seide andPaul F. Barrett, NACA ----------------------- 1087

REPORTS

No.1048. A Study of Effects of Viscmity on F1OW Over

Slender Inclined Bodies of Revolution. By H.Julian Allen and Edward ‘W,Perkins, NACA.. -

1049. Experimental Investigation of the Effect ofVertical-Tail Size and Length and of FuselageShape and Length on the Static Lateral StabilityCharacteristics of a Model With 45° &vcptbackWiDg and Tail Surfaces. By M. J. Queijo andWalter D. Wolhart, XACA -------------------

1050. Formulas for the Supersonic Loading, Lift andDrag of Flat Swept-Back Wings With LeadirigEdges Behind the Mach Lines. By Doris Cohen,NACA -------------------------------------

1061. Ah Analysis of Base Preswre at Supersonic Veloci-ties and Comparison With Experiment. ByDean R. Chapman, NACA----_----------.-..

1052. A Summary of Lateral-Stability DerivativesCalculated for Wing Plan Forms in Supersonic

. Flow. By Arthur L. Jones and Alberta Alkane,NACA -------------------------------------

1053. Investigation of Turbulent Flow in a Two-Dimen-sional Channel. By John Laufer, CaliforniaInstituteof Tech~lology ----------------------

1054. Integrals and Integral Equations in LinearizedWing Theory. By Harvard Lomax, Max A.Heaalet, and Franklyn B. Fuller, NACA. . . . . .

1055. Comparison of Theoretical and ExperimentalHeat-Transfer Charact erbtics of Bodies ofRevolution at Supersonic Speeds. By RichardScherrer, XACA ----------------------------

1056. Theoretical Antiswmmctric Snan Lcadimz forWings of Arbit;ary Plan ~orm at SuisonicSpeeds. By John DeYoung, XACA -----------

1057. Analysis of the Eflects of Boundary-Layer Controlon the Take-Off and Power-Off Landing Per-formance. Characteristics of a Liaison Type ofAirplane. By Elmer A. Horton, Laurence K.Loft in, Jr., Stanley F. Racisz, and John H,Quinn, Jr., KACA ---------------------------

1058. Influence of Chemical Composition on RuptureProperties at 1200° F. of Forged Chromium-Cobalt-Nickel-Iron B=e Alloys io Solution-Treated and Aged Condition. By E. E. Rey-nolds, ,J. W. Freeman, and A. E. White, X.4 CA.-

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Letter of Transmittal

2’0 tlw 0wf7v88 of the Uniied States:In compliance -with the provisions of the act of March 3, 1915, as

amenclecl, establishing the hTdionaI .-dvisory Committee for Aero-nautics, I trammit herewith the Thirty-seventh Annual Report ofthe Committee covering the &cal year 1951.

HARRY S. TRUMAN.

THE WHITE Housq

J.SrARY 98, 1952.

v

Letter of Submittal

~ATIOXAL kW’ISOEY cO~I’lICER FOE &?RONAUTI~

~SmITGTON, D. C., IVmwnber 16, 1961.DFMR?& PmzeIDmNT:In compliance with the act of Congg ap-

proved March 3,1915, as amended (U.S. C. 1946, title 50, sec. 153),

I have the honor to submit herewith the Thirty-seventh Annual Re-port of the Natiomd Advisory Committee for.aeronautics covering theflseaIyear 1951.

The development of nevi types of aircraft slowed materially aineethe end of World War II but, since Korea, progress is now rapidlyaccelerating. The magnitude of the military effort required to checkworld-tide aggression makes it evident that Iunerica% aircraft must

be superior in performance and military effectiveness to those of anyother nation.

The Committee seeks, through timely and adequate research, to as-sure the success of the expandi~a aircraft program. The CommitteeLAieves that in order to support the military effort effectively, itsscope of operations should be increased to the extent that availabilityof scientific manpower viiII permit.

Respectfully submitted.

JRROMJIC. HuNs~qChairman.

TEE PRESLDENT,The White Howe, lTadtington, D. C.

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National Advisory Committee for AeronauticsHeachywtwa, 17fi4F Street NW., Washington 26, D. C.

Created by act of Congress approved March 3, 1915, for the supervision and direction of the scientific studyof the problems of flight (U. S. Code, title 50, sec. 151). Its membership was increased from 12 to 15 by act,approved March 2, 1929, and to 17 by act approved May 25, 1948. The members are appointed by the Presiclcnt,and serve as such withoub compensation.

.J~Ro~E C. FfVNSAK~R,Sc. D., Mmsach uset.ts Institute of ‘l%chnology, Chairman

ALEXANDISRWIZTNORE,Sc. D., Secretary, Smithsonian Institution, T:ice Chairman

DETLEV W. BEOKK, PH. D., President, Johns Hopkins Univer-sity. )

JOHN H. CASSADY,Vice Admiral, United States Navy, DeputyChief of Naval Operations.

EDW-ARDU. COKDOK,PH. D., Director, Nationaf Bureau ofStandards.

HON. THU~AS W. S. DAVIS, Assistant Secretary of Commerce.JAMESH. DOOLITTLE,Sc. D., Vice President, Shell Oil Co.R, M. HAZEN, B. S., Director of Engineering, Allison Division,

General .Motore Corp.WILLIAM LI~TLEWOOD,M. E., Vice President, Engineering,

American Airlines, Inc.THEODOREC. LOKNQUWTiT,Rear Admiral, United States Navy,

Deputy and Assistant Chief of the Bureau of Aeronautic.

HON. DONALDW. NYHOP,Chairman, Civil Aeronautics Board.DONALD L. PUTT, Major General, United States Air Force,

Acting Deputy Chief of Staff (Development).ARIrEUR E. RAYMOND,Sc. D., Vito Presidrmt, Engineering,

Dougkw Aircraft Co., k.FRANCIS IV. REICH~LDHEFBK Sc. D., Chief, United Stat~w

Weathsr Burmu.GORDONP. SAVILLE,Major General, United States Air Form,

Deputy Chief of Staff (Development).HON. \VALTERG. WHITMAN, Chairman, Research and Develop-

ment Board, Department of Defense.THEODOEEP. W’HIGHT,Sc. D., Vice President for Research,

Cornell University.

HUGH L. DRY~EK, PH. D., Ditedor JOHN F, VICTORY,LL. D., Emcufiee Secretaru

JOEY W. CnowLEY, JR,, B. S., A8eociate Diwctor jw Research E. H. CHA~BERLI~,@ecutiueO.&er

HENRY 3. E. REID, D. E~G., Director, Langley Aeronautical Lahorat my, Langley Field, Va.

S~ITH J. D~FRAXCE, B. S., Director, Ames Aeronautical Laboratory, Moffett Field, Calif.

EDTv~RD R. SHARP,Sc. D.f Director, Lewis Flight propulsion Laboratory, Clevehmd Airport, Cleveland, Ohio

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TECHNICAL COMMITTEES

AERODYNAMICS OPERATINGPROBLEMSPOWERPLANTroE AIRCRAFT lNDUSTRYCOYSULTINTJAIRCRAYTCOtiBTRUmION

Coordination oj Resew& Needs of Military and Ctil Aviolion

preparation of Re8earch Prog~arm

Allocution of problems

Prevention of Duplication

Consideration of Inventions

_ti_- . .. .-

LAXGLEYAEROIiAUTICALLABORATORY AMESAERONAUTICALLABOItATORY LEWISFLIGHTPROPULSIONLABO~ATWRYLangley Field, Va, Moffett Field, Calif. Cleveland Airport, Clcvclancl, Ohio

Condud, under unijfed wrdrol, for afl agewsiee, oj wienti.i% research on the jundarnental problems of Jight

OFFIGEOFAERONAUTICALI?JTELLIGEXCEWtwhingt.on,D. C.

Collection, claesi@tion, wrnw”lation, and drkseminotion oj wienttj$c ad technical inforwwiion on aeronnu.tics

VIII

THIRTY-SEVENTH ANNUAL REPORTOF THE

NATIONAL ADVISORY COMMI!M!EEFOR AERONAUTICS

~AS13_ING~OX,D. C7 ~owmber 16,1961.To the Cmgre88 of the United Mateg:

In accordance with the act of Congress, approvedMarch 3,1915 (U.S. C. titie 50, sec. 151), which estab-lished the National Advisory Committee for Aeronau-tics the Committee submits its thirty-seventh annmdreport for the fiscaIyear 1951.

The United States is engaged in expanding militaryaviation to Ievels never before reached except in themidst of a major war. In Korea, our military air-craft are engaged in combat with airplanes of an un-friendly nation evidently able to build military aircraftof increasing capabihties. In this environment, theNACA is responsible for conducting an adequate pro-gram of scientific research to open the way for thedesign of aircraft and missiIesof superior performance.

Since World War II the pace of technical develop-ment has increased. Until then, improvement in air-craft performance as a result of the application of sci-entific research proceeded at what. now seems to be arelati~ely S1O-Wand orderly rate. Modest increases inapeed, climb, range, or altitude were set as reasonablegoals. Compressibility efkts at high speeds were justbeginning to be encountered and indicated a forn~id-able barrier near the mdocity of sound. This barrierhas been found by research and experiment to be leesformidable than supposed, and we now .wethe possibil-ity of radical gains in airphme performance that areof great military significance. Such gains are ak at-tainable by a potentitd enemy.

The increased complexity of modern high performa-nce aircraft rwndts in greatly increased costs, whethermeasured in manpower or dollars, and places more atstake in the succees or failure of the research uponwhich superior performance is predicated. In vie-ivofthe ma=~itude of the national effort to buiId up airpower adequate to our national $ecurity, scientificresearch should proceed on a corresponding sale.

In the years immediately folIowing ‘World War II inappreciation of the probable significance to nationalsecurity of applications of new knowledge of supersonic

213687—5%2

aerodynamics and jet propulsion, the President and theCongress supported the NACA in an intensi~e programof fundamental scienti6c studies in these fields of aero-nautical science. There was an urgentneedtoowmonma serious deficiency of basic information resulting fromwartime concentration of research teams on irrunediateproblems associated vcith the improwment of airpkmesin service. Only by concentration on fundamentalsmay we expect to &d leads to radicaIIy nevi develop-ments which should pay off in the design of future air-craft. We do not know how long the present period oftension wiI1 Iast nor do we know what discoveries anenemy may make.

k addition, the Committee must not negkct Ieasspectacular research to provide engineering informa-tion eesential to the safety and economy of aircraft ofaIl types, both civil and miIitary. h this, the NACAhas responsibility for the scienti6c study and prac-tical solution of current problems, as crystatiedin the discussions of our several subcommittees ofexperts. These subcommittees include designers, user%and research scientists. Research initiated to ache acurrent problem can be readdy translated into practice.Such research, for example, makes possible an increasein thrust of current production engines and improvedperformance of the next Iot of airplanes. The need forextended work in this area has been reflected in ourbudget estimates.

The military research and development program hasbeen increased threefol& but to date the funds and man-power authorized for NACA have not expanded to sup-port adequately the military effort. Therefore, theCommittee urges an expansion in NACA effort to theextent that availability of scieutiflc. manpower willpermit.

Presently, emphasis is on the military applicationsof research, but many of the results of NACA researcheffort are of wdue to civil aviation, as for examplethe work on ice prevention, fire prevention, effects ofatmospheric turbulence, and work on aircraft stabilityand control. Much research for the improvement of

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2 REPORTNATIONALADVISORYCOMMITTEEFOR AERONAUTICS

military aircraft is extended to obtain ckta neededbythose responsible for the design, operation, or regula-tion of civil aircraft.

During the current year the Committee completed theinstallation of atransonic ventilated throat in the 16-foot wincl tunnel at the Langley Aeronautical Labora-tory, This installation is based on an invention bymembers of the NACA staff aud is considered to be ofexceptional importance because it permits model air-plane tests at traneonic air speeds in wind tunnels,hitherto impowible because of the choking of the con-ventional wind tunnel as the air speed approaches thevelocity of sound.

In the formulation of its research programs, theCommittee has been materially assisted by some 400

membem of its 90 technicul connnittees. Tlucw! lllcll)-

bers include scientists from univel%itics,engineers fromindustry; and experts from the civil and milittlry ugen-cies of the Government. The Committee continues toenjoy the loyal and effective support of its civil servicestaff in the execution of its policies and clirectives.

Parts I, 11, and 111 of this t-mnualreport present ur&mn4 of the unclassified scientific activities of theCommittee, a clescription of the Committee’s orguniz/L-tion and membership, ancl the financial report for thefiscal year 1951.

Respectfully submitted.

.TEnoxEC. HUh-SAIiEIt,O}wiwwt

Part I—TECHNICAL ACTIVITIES

RESEARCH ORGANIZATION AND PROCEDURES

COMMI’IT’EE LABORATORIES

Research of the National Advisory Committee forAeronautics is conducted largely at its three labora-tories-Langley Aeronautical Laboratory, LangleyFiekl, Va.; Ames Aeronautical Laboratory, MoffettField, CaIif.; and Lewis FIight Propulsion Laboratory,Cleveland, Ohio. A subsidiary station is located atWallops Island, Vs., as a branch of the Langley Lab-oratory for conducting research on models in flight inthe tranaonic and supersonic speed ranges. At Ed--wards!Calif., is located the NTAC!AHiih-Speed F1ightReseureh Stutiou for research on transonic and super-sonic airplanes in flight. The total number of employ-ees. both technical and aclministrati-re,at these fi-resta-tlone and headquarters in Washington ~as 7,705 atthe enclof the fiscal year 1951.

TECHNICAL COMMITTEES AND RESEARCHCOORDINATION

In carrying out its function of coordinating aero-nautical research the Committee is assisted by a groupof technical committees and subcommittees. The mem-bers of these committees are chosen for their particularknovdedge in a specific field of aeronautics. They areselected from other Government agencies concernedwith aviation including the Deparhnent of Defense,from the aircraft and air transport industries, andfrom scientific and educational institutions. Thesecommittees provide for the interchange of ideas andprevention of research duplication except There par-alIel etiorts me desired. There are four technical com-mittees under the h’ationa~ Advisory Commit-tee forAeronautics:

L Committee on Aerodynamics.2. Committee on Power P1ants for Aircraft.3. Committee on Aircraft Construction.4. Committee on Operating Problems.

Each committee is supported by three to eight technicalsubcommittees.

In addition to the four technical committew~ thereis an Industry Ccmsulting Committee established to as-sist the m~in Committee in formulation of generrd

policy. Membership of this Committee, as well as thetcchnicaI committees and subcommittees, is IiAcd inpart II of this report.

Research coordination is further effected throughdisc~ions between Committee technical personnel andthe research staffs of the aviation industry, educationaland scientific organizations, and other aeronauticalKmencies. The Research Coordination Office is assisted ___by a west coast representati~e -do maintains close con- —tact with the aeronautical research and engineeringstaffs of that geographical area.

RESEARCH SPONSORED IN SCBWITFIC ~D

RESEARCH INSTITUTIONS

For the 1951 heal year the NACA continued to makeuse of the unique research taIents and facilities of uni-versities and other nonprofit scientific institutions tofind solutions for aeronautical problems. Both researchproposals and the results from investigations have beencarefdy reviewed to maintain the quality of this partof the NACA prcgram, and reports of the useful re-sults of the sponsored reeearch hare been given the sameTide distribution as other hTACA reports.

The di-rersity of this sponsored resemch is indicatedby the fact that 19 of the h’ACA technical subcommit-tees retievred proposals for or the results of such in-vestigations dur~u t-hepast year find that 4S reports ofsponsored research were rdemed. The technical as-pects of the pro=-m are included with the descriptionsof work under the -rarious technical sections.

During the 1951fiscal year the following institutionsparticipated in the contract reeearch program:

h~ational Bureau of Standards, Forest ProductsLaboratory, Armour Research Foundation, BattelleMemorial Institute, Polytechnic Iistitute of Brook.1~,Brown University, California Institute of Technolo=q,Unkersitj- of California, Uni~ersiQ of California at1% Angeles, Carnegie Inetitute of Technolo=q, Uni-versity of Cincinnati, Cornell University, University ofF1orida. Georgia Institute of Technology, HarvardUni-remity, Illinois Institute of Technolo=q, llni~e~”tyof Illinois, Iowa State College, Johns Hopkins Univer-sity. Massachusetts Inst.itute of Technoloeq, University

3

4 REPORTNATIONALADV~ORYCOIIMI’l?TEEFOR ~ROKAUTICS

of Michigan, Mount Washington Observatory, Newl’ork University, University of Notre Dame, OhioState University, Pennsylvania State College, Prince-ton University, Purdue University, Stanford Univer-sity, Stevens Institute of Technology, Syracuse Uni-versity, Texas Agricultural and Mechanical College,University of Virginia, and University of Washington.

RESEARCH INFORMATION

Research results obtained in the Committee’s labora-tories and through research contracts are distributedin the form of Committee publications. Formal Re-ports, printed by the Government Printing OfficE+con-tuin unclassified information nnd are available to thegeneral public from the Superintendent of Documents.Technical Notes, released by the”Committee in limitednunlbe~~,also contain unclassified research results of amore or less interim nature and me distributed to inter-ested organizations throughout the country. Fre-quently, research results which will ultimately be pub-lished in Report form are issued initially m TechnicalNotw in the interest of speedy dissemination of data toAmerican technical people and organizations. Trw~s-lations of forei=m material are issued in the form ofTechnical Memorandums.

In addition to unclassified publications the Com-mittee prepares a large number of reports centainingclassified research information. For reasons of na-tional security, these reports are controlled in their cir-culation. From time to time the classified reports areexamined to determine whether it is in the national. in-terest,to dechssify them. If it is found desirable to de-classify the reports, they may be published as unclassi-fied pape~a.

Another important means of transmitting quicklyand efficiently the lateet information in a particularfield of research directly to designers and engineersworking in thmtfield is the ho]ding of technical confer-ences from time to time at an appropriate NAC.4laboratory. Several conferences of this nature wereheld during the past year.

The Oilice of Aeronautical Intelligence was estab-lished in 1918 as an integral part of the Committee’s

activities. Its functions are the collectiol~nnd cluseifi-cution of technical knowledge on the subject of aero-nautics, including the results of reseurch und experi-mental work conducted in all parts of the world, andits dissemination to the Department of Defcme, uir-craft manufacturers, educntionnl institutions, and otherinterested people. American and foreign reports ob-tained are analyzed, classified, and brought to the at-tention of the proper persons through the meclium ofpublic and confidential bulletimz.

AERONAUTICAL INVENTIONS

By act of Congrew, approved July 2, 1926 (U. S. C.title 10,sec. ttltlr), an Aeronautical Patents and DesignBoard was establishedconsisting of the Assistunt Secre-taries for Air of the Departments of War, Navy, andCommerce. In accordance with thut act as amendedby an act, aliproved March 3, 1927, the National Advi-sory Committee for Aeronautics is charged with thefunction of analyzing and reporting upon the technicalmerits of aeronautical inventions and designs submittedto any agency of the Government. The AeronauticalP~ltel~tsand Design Board is authorized, upon thefavorable recommendation of the Committee to “deter-mine whether the useof the desiamby the Government isdesirable or necessary and evaluate the design and fix ‘its worth to the United States in an m-nountnot to ex-ceed $75,000.”

Reco=tizing its obligation to the public in this respectthe Committee has continued to accord to all corre-spondence on such mntters full consideration. All pro-posals received have been carefully analyzed and evalu-ated and the submitters have been ndvised concerningthe probable merits of their suggestions. Mm]y per-sonal interviews have been granted inventom who vis-ited the Committee’s offices, and technical informtitiunhas been supplied when requested.

* * * * *

Tho follo~ving detailed summary of m]cltissifiedre-search, completed during the fiscal year 1951, is organ-ized to reflect the areas of research over which eachtechnical committee and related subcommittee hascognizance.

AERODYNAMIC RESEARCH

During the past year there has been an increase inresearch directed specifically at the problems of lligh-speed airplanes and guided missiles. Aerodynamic re-search to permit eflicientoperation of airphmes at tran-eanic speeds has continued to receive special emphasis,ancl information has been obtained in this speed rangefrom flights of special research airplanes, rocket.-powerecl free-flight models, freely-falling bodies, and

from very small models on wind-tunnel bumps or by thewingflow method in flight. There has, however, beena serious need for techniques to permit detmiledsys-tematic large-scale experiments to be made in windtunnels through the speed of sound. As a result ofextensive resmrch on wind-tunnel design, suitable tech-niques have been develope~ and the Langley 8-foot and16-foot -wind tunnels were modhd to permit testing

‘------– COMMITTEE FOE AERONAUTICS 5REPORTNATIONALADVISORY

through the speed of sound. These modMed tunnels arecontributing to a better understanding of aerod-cproblems in the transcmicspeed range.

Theoretical and experimental research on high-speedairplane design problems has been directed generally atthe establishment of technical information to permitthe selection of the most eilicient. con.tlguratione forfIights at traneonic and supersonic speeds which willakm have satisfactory &ng characteristics at lowspeeds for landing and take-off. As the high-speed re-quirements increased, the landing requirements havebecome more di3icult to meet and it has been necessaryto continue research at low speeds on these problems

In addition to studies of performance problems ofguided missiles,considerable attention has been directedduring the past -year to the problems of stability andcontrol. In this field particular emphasis has beenpluced on the cross-coupling effecl.sexperienced by vari-ous missile con@mat ions and on automatic controlproblems.

The AYACAis assistedin guiding the aerodynamic re-senrch activities of its laboratories by the Committee onAerodynmnics and its eight technical subcommittees.Results of the research which are most pertinent to thedesign and de-relopment of military airplanes and=~ided missiles are summarized and presemtedat tech-nical conferences held during the year with the repre-sentatives of the military sertices and their contractor?in order to assist designers in making edy applicationof these results.

In the sectiom which follow a description is given ofsome of the Committee’s recent urdassfied work inaerodynamics.

FLUID M-ECH-4NICS

lncestigation of Airfoils atLow Speeds

lkw-speecl instigations of tvro-dimensiormlairfoilshave been devoted to a large extent.to the study of flowphenomena at high lifts and the de-relopment of meth-ods for the impro=rementof high lift characteristics.Reported h Technical Note 2235 is an inm.stigation ofthe boundnry-htyer and stalIing characteristics of theX.ICA f34.!-010 airfoil section in the Ames 7- by 10-footwind tunnels. The results show the small region ofseparated tlom or ‘bubble” near the leading edge, char-acteristic of airfoils with small leading-e~~e radii. Atan angle of attack of 9.5° the separmteclflow failed toreattach to the surface! causing the stall. Since therewas no turbulent separation at the trailing edge, thelift-curve peak ms sharp and the sttdl occurred sud-denly and -withno warning.

.ti investigation was also conducted in the Ames 7-by IO-foot wind tunnels to determine the possibility of

deIaying the flow separation that occurs netir the led-ing edge of the NACA 6&O12 airfoil section and of im-proving its staI1ing characteristics by modifications ofthe contour near the leading &~e. This study is re-ported in Technical Note 25!28. The greatest improve-ment vms obtained with moditlcations that incorporatedan increase in camber and modifications to the leading-edge shape tveremore effective than drooped-nose flaps.

The re.tits of a comprehensive investigation of thestalling characteristics of airfoil sections at low sub-sonic speeds in the Ames 7- by lo-foot wind tunnelshave been summarized in Technical Note %02. Sev-eral types of stall encountered with airfoils rangingin thickness from that for a slow, light airplane to thatfor a possible supersonic application are described indetaiI in conjunction with the characteristic flows inthe boundary Iayer.

TIM increases in airplane lift-drag ratio associated _.with increasing aspect ratio are limited by the highprofle-drag coefficients associated with the thick wing-roct sections which are structurally necessary on wingsof high aspect ratio. An investigation has thereforebeen made of NACA 6&eries airfoils of 3S2-and 40-percent-chord thidrn-w in the Langley lo-w-turbulencetunnels to determine whether the high profiledrag co-efficientsof thick airfoils can be reduced by bonndary-layer control through a single suction slot. The re-sults obtained for the .%2-and 40-percent-thick sectionstogether with other a~ailalde airfoiI section data -wereused to crdcuIate the characteristics of a number ofhypothetical wings. These calculations indicate thatthe maximum attainable lift-drag ratio of structurallyfeasible wings and of the corresponding airplanes maybe increased appreciably by the use of such thick wingswith boundary-layer controL The results are pre-sented in Technical Note 2405.

It has been found that in the higher ranges of land-ing speeds compressibility effects on maximum lift canbecome appreciable. As part of a program to explorethis phenomenon, the effects of Mach number andReynolds number on the maximum Iift coefficient of awiqg of N’ACA 66-series airfoil sections were deter-mined in the Langley M-foot preesure tunnel and arepublished in Technical Note 225L The ranges of 31achnumber and Reyuolds number extended up to 0.34 andS.0 million, respectimly. It was found that for a givenvalue of Mach number, the vaIues of maximum lift co-efficient were increased when tie Reynolds number -wasincreased. For a given value of Reynolds number, anincrease in Mach number at first caused only smalI re-ductions in masimum lift coefficient, but the reductionvias large after the critical speed was esceeded.

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6 REPORTNATIONALADVISORYCOWTTEE FOR AERO~AllTICS

Theoretical Investigations of Two-Dimensional Com-pressible Flows

Theoretical investigations of two-dimensional com-~JIWSSibh3flows are being continued with particular ref-erence to the difficult transcmic speed range. At theLangley Laboratory the Prmdtl-Busemann small-~r-turbation method has been utilized to obtain the flowof n compressible fluicl past a wave-shaped, infinitelylong wall. ~len the essentialrmumption for transonicflow is introduced—that all Mach numbers in theregion of flow are nearly unity-the expression for thevelocity potential takes the form of a power series inthe transonic similarity parameter. On the basis ofthis form of the solution, an attempt has been made tosolYe the nonlinear clifferential equation for transonicflow past a wavy wall. The results of this analysisexhibit clearly the inherent difficulties encountered innonlinear flow problems. Nevertheless, the investiga-tion has been carried in a rigorous manner to the pointwhere the question of the existence or nonexistence ofa mixed potential flow free of discontinuitks can besettied by the behavior of a single power series in thetransonic similarity parameter. The calculation of thecoefficients of this dominant power series has been re-cluced to a routine computing problem by means of re-cursion formulas resulting from the solution of theclifferent.ialequation and the boundary condition at thewall. One of the results of the analysis is the rigorousstatement of a limit of applicability of the transonicsimilarity concept. The results are presented inTN 2883.

In Technical Note 2253 it is shown that it is pos-sible to solve the Prandtl-Busemann iteration equationsby means of the familiar concepts of a distribution ofsources and sinks. The method is limited to the treat-ment of thin, sharp-nose, symmetric, two-dimensionalprofiles. An explicit expression is derived for thesecond-order velocity potential and velocity compo-nents, and a method for obtaining higher-order termsis indicated. The velocity at the surface of the Kaplanbump is evaluated to illustrate the method.

The relaxation method has been proposed as a meansof calculating prcwure distributions on two-dimensionalbodies at high speeds, and a comparison is shown inTechnical Note 2174 between the experimental pressuredistribution for an NACA 0012 profile and the theoret-ical pressure distribution obtained by this method.The comparison ehowed good agreement at low speeds,but at higher Mach numbers the theoretical calculationsindicated higher negative pressurecoefficientsthan wereobtained experimentally.

An integral method of calculating two-dimensionalcompressible flows past thin airfoils, with particularreference to the transonic speed range is presented in

Technical Note 2180. By on appropriate choice ofstreamline curvature, this method permits the flow pat-tern about a thin airfoil to be calculated in a conlpara-tively simple manner. The results presented includevelocity clistributions for various symmetric sections.Comparison -withother theories and with nvailable ex-perimental data indicate at least qualitatively goodagreement.

The transonic similarity law for two-dinlensionalflow, derived by von Karman, has been investigt~teilbyan iteration procedure ancl is presented in TechnicalNote 2191. The boundary condition of zero velocitynormal to the body was satisfied tit the body ratherthan near the body, as was done by von Kmman. Theresults showed that the velocity potential can be ex-pressed in terms of a similarity parameter and were inagrwment with those.of von K~rman.

Theoretical investigat.ions of two-dimensional com-pressible flows by several educatidhal institutiona undercontract to the NACA are being continued. At the NewYork University an approximate method of solvingthe nonlinear differential equation for two-dimensionalsubsonic compressible flow by means of the vuriationalmethocl is being used. The general problem of steadyirrotational flow past an arbitrary body is formulatednnd two exmnples have been carried out, namely, theflow past a circular cylinder and the flow pnst u thincurved surface. The variational method yields resultsof velocity and pressure distributions which comparewe]] with those found by other methods.

T’he problem of two-dhnensional flow behind acurved stationary shock wave has been considered ana-lytically at the Massachusetts Institute of Technology.The method, which is presented in Technical Note 2364,assunms a given shock-wave shape, which autonmti-cally determines certain initial conditions on the flowvariables; and”the flow pattern, including any bodyshape, follows from the initial conditions. Approxi-mate analytic expressions are found for the streumfunction in the subsonic region following the shock and,after the stream function is obtained, the flow densityis deterinined by Bernoulli’s equation, which connectsthe density with the derivatives of the stream function.The final solution can then be determined from thevelocity field thus obtained.

Technical Note 2356 presents the results of w study,made at Cornell University, of the two-dimensionaltransonic flow past airfoils. The problem of construct-ing solutions for transonic flow over symmetric air-foils is treated and simplification of the mapping of theincompressible flow is emphasized. In the case of asymmetric Joukowski airfoil without circulation, themapping is relatively simple, but the coefficients in thepower seriw ar~ difficult to evaluate. As a means of

REPORTNATIONALADVISORYCOMMITTEEFOR AERONAUTICS 7

simplification, an approximate flow is used which differsonly slightly from the esact incompressible one whenthe thiclme= is small. IHow with circulation is alsaconsidered by the same method.

At the Johns Hopkins University an in-wstigationhas been made of the transient behmcior of an airfoilin supersonic flow clueto pitching, flapping, and verticalguws by means of the Fourier integ-d method. By~~i~~ n convolution inteeqal, the aerodynamic effectof an~ arbitrary motion of the airfoil can be determined.if the aerod-punic response of the airfoil to a step-function disturbance is known. As useful examples,the harmonically oscillating airfoil with differeut modesor degrees of freedom is analyzed for the complete timehistory, for the case in which the motion starts abruptlyfrom rest. In Carrying out the irrrestigation: a new in-tegral has been introduced -whichis beliewd to play anequindent ptirt in supersonic flutter to the Theodorsenfunction in the flutter problems of incompreseible flow.The results are presented in Technical Note 2333.

Investigation of Wings and Bodies at Tranaonie andSupersonic Speeds

An essential part of the correlation of aerodynamicdata is a lmovrkdge of the correspondence between theflow fields about similar bodies at related speed condi-tions. An investigation -was made, therefore, at theAmes Laboratory which extended similarity htws fortnmssnic flow to include finite-span wings. Under theassumptions of transonic small-perturbation potentialtheory, it was shovrn that similitude in preesur% Iift+pitching moment, and pressure-hag coefficients dependupon the constancy of two parameters. The applica-tion of these results led to an essential improvement inthe manner of relating experimental wing character-istics at near-sonic speeds. This work has bwm re-ported in Technical Arote2X3.

Source distribution methods for evaluating the aero-dynamics of thin finite wings at superwmic speeds aresummarized and extended in Report 951. The funda-mental equations were derived in general form for bothtirue-independentand time-dependent -wingmotions andwere applied to solve a large variety of aerodynamicprob~ems. In Technical h’ote 2303 a method wcs devel-oped for relating the solution of a wing to the lmownsolution of a simpler wing. This method permits com-plicated flow fields to be solved in a straightforwardmanner.

At the Johns Hopkins Uni-iersity, Ton Karman’sFourier integral method in supersonic wing theory,derived directly from the basic concepts of the harmonicsource and doublet+has been applied to investigate thegeneral solution of the wave drag of a tapered sweptwing with a symmetrical diamond airfoil profile, cover-

ing -mrious geometrical arrangements of the planform.The theory has akssbeen appIied to find the downwashdistribution in the pkme of the wing on which the pres-sure distribution is preassigned. A number of examplesare given. This work has been done under contract tothe XACA and the results are presented in TechnicalhTote2317.

The flow around cormswithout axial symmetry andrnovin~ at supersonic velocity has been anttlyzed andthe results of this mdysis are presented in TechnicalA-ote2236. Singular points were shown to exist in theflow around the cone if no axial s.@nmetry exists. Theconcept of a vertical layer around the cone at smallangles of attack -wasintroduced! and the correct valuesof the first-order terms of the velocity components -weredetermined. It was shown that good agreement withexperimental results can be obtained if the completeequation for the pressure distribution is used.

The transonic similarity law, as applied to bodies ofresolution, has been investigated and the results pre-sented in Technical Note 2239. The resuh obtainedwere in approximate agreement with those of ron Kar-man in the region of the flow field not too cIose to thebody. In the neighborhood of the body a diflerentsimilarity la-wwas obtained. In another investigationthe integral method used to obtain compressible flowpast tvro-dimensional shapee (Technical Note 9130)was appLiedto the calculation of the compressible flowpast slender bodies of revolution. Good agreement ofthe resulting velocities on eUipsoide of revolution withthose obtained by other methods was found. The in-vestigation is reported in Technical Xote 2245.

The pressure acting on the base of .abody of revolu-tion ffy@g at supersonic velocity is of considerable im-portance because the bass drag can, in mme case%rep-resent more than half of the total drag. It is essentialthat the factors contributing to this drag be exp~oredto enable a reasonable drag prediction to be made in thedesi=m of missiles and to pro-ride information fromwhich possible base-drag reductions may be realized.One such factor is the presence of tail surfaces near thebase of the body. Since the pressures in the ~icini@ ofthe trailing edge of the tafi surfaces at zero angle ofattack me normally less than the free-stream -ralues.the interaction of these pressures with the flow behindthe base may produce a reduction in the base pressureand. hence, an increase in the base drag. Accordingly,experimental memurements of the base pressure on anunboattailed body of re-rolution in combination withrectangdar tail surfaces were made at the .hnee Lab-oratory to investi=~te the eflects of tail surfaces on basedrag. The results of the investigation showed that the . __addition of tail surfaces with the trding edge near thebase of the body incurred a siF@ficant increase in base

8 RIGPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

drag. For example, the increase was about 70 percentat a Mach number of 1.5 for a cruciform tail having a10-percent-thick biccmvex airfoil section. The base-drag penalty due to tail surfaces was found to increasewith an increase in the airfoil thickness ratio and withthe number of tail surfaces and to decrease with an in-crease in Mach number, It was also found that thisbase-drag increment could be essentially eliminated bymoving the tail so that the trailing edge was about onechord-length ahead of or behind the base of the body.The results are presented in Technical Note 2360.

Research in the Hypersonic Speed Range

ln the Thirty-sixth Annual Iteport several facilitksand techniques permitting supersonic research to be ex-tended into the hypersonic speed range were described.During the past year this work has been continued and,in mklition, progress has been made in extending the-oretica~calculations inti the hypersonic range.

The accuracy of Tsien’s hypersonic similarity rule,and the range of Mach numbers and finenessratios overwhich it can be applied, have been investigated theo-retically. A first investigation, which ignored rotationeih.cts, showed that the rule applied with good ac-curacy over a range from moderate supersonic speedsup to hypersonic speeds for a wide range of body fine-ness ratios. This work has been reported in TechnicalIYote2250. An investigation of the effects of rotation,presented in Technical Note 2399,showed that the omis-sion of these effects in the previous investigation didnot have a significant effect on accuracy within the ex-pected range of validity of hypersonic similarity.

An analysis has been performed to determine the liftand drag characteristics of conical bodies, flat plates,cylinders and spheres in a free-molecule flow fieldThe calculations were made for a range of Mach num-bers from Oto 24. It was found that the aerodynamiccoefficientsapproached constant values at the very highspeeds. It was also found that the lift-drag ratio forbodies in a free-molecule flow &ld are extremely low,The results are reported in Technical Note 2423.

Theoretical investigations have also been made todetermine the similarity law for hypersonic flow aboutslender three-dimensional shapes in tern-isof customaryaerodynamic parameter. A first investigation, whichconsidered ordy steady flow-s,employed the law to deter-mine relation for correlating t.kmpre9sure9 acting on,and the aerodynamic coefficients of, related bodies andresults are reported in Technical h~ote2443. In thespecial case of inclined bodies of revolution, the expres-sions for the aerodynamic coefficients were extended toinclude somesignificant effectsof the viscous crow forc~

A theoretical analysis which determines the airfoilprofile having minimum pressure drag for a given

structural requirement was reported in Technical Note2264. The general method was developed and appliedto linearized flow theory. The principal results of theinvestigation were that the optimum airfoil at hyper-sonic velocities has a trailing-edge thickness slightlyless than_file maximum airfoil thickness and the opti-mum airfoil at supersonic ve10citie9 generally has amoderately thick trailing edge. Curves were developedwhich enable optimum airfoil profiles to be determinedrapidly for a given Mnch number, base pressure, andstructural requirement.

Condensation of the components of air has been foundto occur in hypersonic wind tunnels. Because of therapid expansion and cooling of the air in the nozzles ofthesetunnels, the temperatureof the air drops below theliquefaction point. In order to study this condensationprocess, the Langley Laboratory has made m investi-gation of optical methods for measuring size and con-centration of condensation particles, and it has beenfound that the polarization and angular distribution oflight scattered by condensation particles can be used tomeasure these quantities. The results of this investig-ation are presented in Technical Note 24L41.

Boundary-Layer Researeh

The existence of localized regions of laminar-bound-ary-layer separation on airfoils both behind the positionof minimum pressure at the ideal angle of attack andnear the leading edge at high angles of attack has beenrecognized, but the parameters controlling such regionshave not been fully understood. Consequently, an ex-perimental investigation was made at the Langley Lab-oratory to study the localized region of laminar sepa-ration behind the point of minimum pressure on anNACA 668-018 airfoil section at zero nngle of atttickand at several Reynolds numbers. The results, pre-sented in Technical Note 2838, confirmed the idea thatsuch separation regions are characterized by a length oflaminar boundary layer followed by transition and sub-sequentreattachment as a turbulent boundary layer andestablished some of the quantitative characteriatim ofthe phenomenon.

At the Lewis Laboratory an analysis has been mtideof the stability of the laminar boundary layer betweenparallel streams of an incompressible fluid. Calcuhl-tions based on this analysis showed that the flow insta-bilityy occurs at much ~ower Reynolds number for thefree boundary layer between streams than for theboundary layer on a flat plate with no prassure gradi-ent. The results of this study are presented in Report97!).

An investigation of methods for treating the three-dimensional compressible laminar boundary layer isreported in Technicnl Note 2279. The equations of mo-

REPORTNATIONALADYLSORYCOMMITTIIIIFOR AEEOX.4UTICS 9

tion are shown therein to be shnplifwd by the intro-duction of a tvio-component vector potential and bythe use of z transformation which converts the equa-tions into nearly incompressible form. Several ex-amples, inchding the flow over fiat plates with arbi-trary leading-edge contours, are discussd.

h’umerical solutions of quantities appearing in theTon Karman momentum equation for the developmentof a turbulent boundary layer in phme and in radialcompressible flows along thermally insulated surfacesare presented in Technical h-ote !X337for a range ofMach number from 0.1 to 10. Through the use ofthese tables, approximate calculation of boundary-layergrowth i9 reduced to routine arithmetic computation.

Experimental data, from se~eral sources, for skinfriction of turbulent boundary layers under adversapressuregradients axe analyzed in !13iwhnicdNote 2431.Data obtained by momentum-balance methods werecompared with data obtained by hot-wire and heat-trmsfer methods. A new integral energy parametervias introduced and its reIation to skin-friction datawas demonstrated on the basis of avaiIable material.

At the Ames Laboratory an analysis has been madeto determine the skin-friction tmd heat-transfer char-acteristics of the turbulent boundary layer on a fhtplate at supersonic speeds. A review of e+.g anal-yses has ah been made and a test performed in theAmes heat transfer tunnel to measure the skin Elctionin the turbukmt boundary layer of a flat plate at a Machnumber of 2.4. It was found that the anaIysis whichmost closely corresponded to the experimental resultsviasan extended version of the Frankl-Toishel analysis,which has been reported in TeckicaI Memorandum1053. The test data and anal@s have been reportedin Technical Note 2305.

A series of heat-transfer investigations were con-ducted on bodies of resolution with huninar boundarylayers at Mach numbers from 1.49 to 2.13. In addition,a comparison between theory and experiment has beenmade for a body of revolution with a huuinar bound-ary layer and a nonuniform surface temperature. Thetheoreticrd and experimental heat-transfer redts arein good agreement for both heated and cooled bodieswith both uniform and nonuniform surface tempera-tures. The qualitati~e effects of heat transfer on transi-tion were found to be in agreement with theimplications of Lees’ boundary-layer-stability theory.

Detailed measurementsof shock-wave boundary-layerinteraction which have been made in -windtunnels harebeen limited to small or moderate Reynolds numbers:and previous flight tests at high Reynolds numbershave been limited to pressure measurements. There-fore, teats were made on an airplane w@ in fight to

investigate the region of shock-wave interaction witha thick turbulent boundary layer at fuH-scale flightReynolde numbers, utilizing both a schlieren apparatusnnd pressure meusurwnents. Good correlation vriththeoretical and mind-tunnel investigations of boundary-layer slmck--iva~einteraction was obtained, particularlyvrith respect to the lower Mach numbers at which aforked or bifurcated type of shock wave appearedThe bonndnry layer did not appear to thicken behindthe normn] shock wa-re. Considerable thickening, asso-ciated -with separation, did occur, howe-rer, with in-creasing Mach number after the formation of the forkedshock vrm-e.The density gradient in the boundary layerappeared to increase markedIy just behind the shockvia~e. This stronger gradient, howe~er, appeared tobe dissipating at approximately five to six boundary-hger thicknesses behind the shock.

At the Lewis Laboratory supersonic flow againstbhmt bodies placed in boundary laprs or vvakes hasbeen imrestigated and is discussed in TMhnical Note2418. It was concluded that wedge-shaped or conicaldead-air regions shouId form ahead of the body if partof the upstream velocity protHe is subsonic and if thebody is fairly thick relative to tha initial boundarylayer or wake thickness. A quantitative theoreticalanalysis of this type of flow was made and the results-werecompared with experiment.

In a contract investigation carried out at the Cali-fornia Institute of Technology, measurements havebeen made at 31ach numbers from about 1.3 to 1.5 ofreflection characteristics and the relative upstream in-fluence uf shockwaves impinging on a flat surface withboth laminar and turbrdent boundary layers. The dif-ference between impulse and step waves is discussed andtheir interaction with the boundary layer were com-pared in Technical Note 2334. General considerationson the experimental production of shock -waves fromwec@e and cones and examples of reflection of shockwaves from these bodies vverepresented, as vvere alsosome examples of reflection of shock mares from super-sonic shear layers.

At the National Bureau of Standards an inw#iga-tion sponsored by the NACA was conducted on a turbu-lent boundary layer near a smooth surface with pressuregradients su%icient to cause flow separation. TheReynolds number was high, but speeds -were entirelywithin the incompressible flow range. The i.nv~a-tion consisted of measurementsof mean flow, three com-ponents of turbulence intensity, turbulent shearingstress, and correlations betvieen two fluctuation compo-nents at a point between the same component at differ-ent points. Results are given in Technical Note 2133in the form of tables and graphs. The discussion deals

10 REPORTISATIOX-.4LADVISORYCOMMITTEEFOR AERONAUTICS

first with Sepmdion and then with the more fundamen-tal question of basic concepts of turbulent flow.

Aerodynamic Heating and Heat Transfer

As wm pointed out in the Thirty-sixth Annual Re-port, knowledge of aerodynamic heating and heat truns-fer phenomena has become of increming importance asairplane and missile flight speeds have increased intothe supersonic region, and during the past year con-siderable effort has been directed toward the under-standing of these phenomena.

Tests have been conducted at the Ames LCLIIOLTttOrytodetermine the effect of surface heating on the transitionReynolds numbers on a flat plate at n Mach number of2.4 It was found that surface heating had a strongeffect in loviering the minimum Reynolcls number fortransition. Measured skin-friction coefficients for tkehuninar portion of the boundary layer were in excellent~greement ~lrithother investigations and were 35 per-cent higher than the values predicted theoretically byCrocco. The data have been reported in Technical Note2351.

Most aircraft or missiles-willnot have a constant sur-face temperature. Consequently, it is necessary to de-termine the effect of a variable surface temperature onthe local heat-transfer rate in order to clesign skin-cooling systems. An analysis has been made whichshows the effect of a variable stream-wise surface temp-erature on local heat-trnnsfer rates. An interestingside light arising from the investi=ntion shows that theuse of plug-type heat metem?in ~hich a sma~ segmentof the aircraft skin is heated or cooled to a differenttemperature than the surrounding skin, may introducelarge errors in the determination of the local heat-trans-fer coefficients. This analysis has been published asTechnical Note 2345.

An analytical method is presented in Technical Note9996 for ob~ining turbulent temperature recovery fac-tors for a thermally insulated surface in superscmhflow. The analysis, conducted at the Lewis Laboratory,indicated that the recovery factor decreased with in-creasing Mach number. For the range of Prandtl num-ber considered (0.65 to 0.75), the recovery factors at astream Mach number of 10 -were,on the average, about5 percent lower than the limiting values at zero Maohnumber.

A comparison has ben made of free-molecule-flowtheory with experimental measurements of drag andtemperature-rise characteristics of a transvene circularcylinder. The measured values of the cylinder center-point temperature confirmed the salient point of theheat-transfer analysis, which was the prediction that aninsulated cylimder would attain a temperature higherthan the stagnation temperature of the stream. Good

agreement vrasobtained between the theoretical and ex-perimental values for the clrng coefficient. The chttuhave been reported in ‘rechnical Note 2244.

Experiments have been made at the .4nles Laboratoryto determine the heat-transfer characteristics of cylin-ders over a wide range of densities encompassing thefree-molecule, slip and continuum flow regimes, cmdtheresults me presented in Technical Note 2438. Gooclcorrelation of the dntti was obtained over a range ofReynolds numbers from 0.02 to 100 and a rnnge of Machnumbers from 1.9 to 3.2. The Knudsen number (ratioof rnecmfree molecular pnth to cylinder dinmeter) var-ied from 0.02 to 10. Several importnnt conclusionswere d~a~n from the resuks of this investigation: Itwas found that fully developed free-nlolecule flow oc-currecl when the Knuclsen number was 2 or greater,For Knudsen numbers greater thun 0.2, the Wnpemturerecovery fnctor exmedeclunity even though free-molecu-lar flow was not fully developed.

In an investigation at the Lewis Laboratory, analyseswere made for fully developed huninar and turbulentflow in smooth circular tubes of fluids having a Prandtlnumber of 1.0. The analyses took into considerationthe variation of fluid properties. 17elocity and tenl-perature profiles, together with 10CS1hwlt-tranefer andfriction coefficients,were predicted. In order to checkthe analysis for turbulent flow, velocity and temperatureprofiles and corresponding local heat-transfer and fric-tion coefficientswere also experimentally determined forair in smooth tubes at high heat-transfer rates. Theanalyticul and experimented results were found to bein good agreement. Both indicated that for the tur-bulent flow of gases the rndial velocity and temper-ature profiles tended to become more uniform as the sur-face-to-fluid temperature ratio increased. At conshmtReynolds nunlber, the local heat-transfer and frictioncoefficientsdecreased with an increase in surface-to-fluidtemperature r~tio. The effects of temperature ratiocould be eliminated when the fluid properties, includingdensity in the Reynolds number, were evaluated at atemperature close to the avernge of the fluid and surfacetemperatures. The results of these cmalyses are pre-sented in Technical Notes 2242 and 2410.

Average heat-transfer and friction coefficients havealso been measured for the turbulent flow of air insmooth tubes. This investigation covered an over-allrange of Reynolds numbers up to 500,000, tube exitMach numbers up to 1.0, inlet-air temperatures from535° to 3050° R., average surface temperatures from535° to 1500° R., lengthdiameter ratios from 30 to 120,and heat fluxes to 150,000 BTU per hour per squarefoot. Three tube entrance configurations were studied.Most of the data are for heat addition to the air; someresults are for heat extraction from the air. Data have

REPORTXATIOXALADYIEORl”COMMITTEE FOR AERONAUTICS 11

tdsobe+mobtained for tubes of noncircuhu- cross section..-in effect of surface-to-fluid temperature ratio wasfound to exist v-hen the average coefficients were corre-lated with other pertinent varinbles by courentionatmethods. The effect was eliminated in the same nmn-ner as for the local coefficients. Correlation equationsfor heut transfer and filction mere obtained which nde-quately represent all the experimental data for smoothtubes.

An analytical investigation of the compressible flowprocesses occurring in the passages of high heat-fluxexchangers is continuing at the Lewis Ikboratory.Charts are presented in Technical Notes 21S6 and 2328for convenient determination of the compressible-flowpresmre drop sustained by monatomic and diatomicgases ~as+mmingconstant heat capacities durirqg theprocess) flowing at high subsonic speeds in constant-mreapassages under the simuhaneous influence of fric-tion and heat addition.

STABILITY -AND CONTROL

Static Stab&ty Inw3&igations

The use of end plates has been suggested as a pos-sible memnsof relieving some of the acl-ieree laterulstability and contrcd problems experienced with sweptwings. & investigation was therefore conducted in theLangley 300-mph 7-by 10-foot tunnel to determine theeffects of end plates of various sizes and shapes on thestability and control characteristics of se-rera~sweptwings. The results of this investigation, presented inTechnicrd Note 2229, indicate that at lovi lift coefficientsthe addition of end plates increased the slope of the liftcurye, reduced maximum lift-drag ratio, generaIIy de-creased maximum Iift coefficient, and increased longi-tudinal stabiIity. It -wasabm found that the variationof effective dihedral-with lift coefficientfor the wing-endplate combinations investigated was reduced by an in-crease in the size of the end plate.

A kno-wledgeof the character of the dovinvm.ehfieldsbehind wings is required for the rational design ofhorizontal tail surfaces as weII as for the analysis of thelongitudinal stabiIity characteristics of an airplane,One theoretical study of this problem has resulted inthe development of a metbd for calculating the down-wash field behind lifting surfaces at subsonic and super-sonic speeds. A description of the method, togetherwith an illustrative example of its use, is contained inTechnical Note 2344. In connection with anotherstudy, a series of charts and tables was prepared from-which the do-wmrash behind ho~hoe vortices in in-compressible flow can be obtained. The use of thesecharts and tables in connection with the calculation ofthe down-wash behind wings of arbitrary planform is

described in Technical X’ote 2353, which also contains .. .ilhetrative examples. Report 9S3 describes the use ofline vortex theory for the calcrdation of supersonicdo-ivnmsh and Technical &Tote2141 contains charts forthe estimation of dovinwash behind rectangular, trap-ezoidal, and triangular wings which -wereprepmed onthe basis of Iine rortex theory.

Studies of Dynamic %ability

At the Ames Laboratory the dynamic latertd etabilityclmracteristim of a dive-bomber type of airplane wereinvestigated in ~Uht to determine the cawssof a small .—ampIitude continuous motion referred to as “snaking.”The resdts of this inwstigatio~ reported in TecbmicalNote 2195, indicate that the ffoat@ characteristics ofthe rudder were affected by Mach number and had anappreciable effect on the snaking of the airplane. Rud-der modifications resulting in an increase in the restor-ing tendency of tie rudder proved successful in elimi-nating this undesirable lateral oaciIIation.

The e.f?ectsof control centering springs on the appnr-ent spiral stability characteristics of a typical high--wingpereonal-owmerairplane have been investigated inflight. Control centering was provided for both theailerons and rudder by means of preloaded springs.Results of the investigation, reported in Technical Note2-413,show that the airplane appeared to be spirallyunstable with controls free when the center@ springsviere diseng~med because of moments resulting fromout-of-trim control position. With centering springsengaged, however, the airplane quickly returned tostraight and level fight with the controb freed follow-irg an abrupt disturbance. The report also includes in”formation concerning the flfi~ qualities of the air-plane in rough air.

At the Langley Laboratory free-flight-tunnel studieswere made to determine the efects of mass distributionon the lovr-speed dynamic lateraI stability and controlcharacteristics of a free-flying model. In this investi- .-gation the longitudinal and lateral mass dissributiousof the model were wried, both independently and si-mrdtaneously, -whilethe reIative density factor was heldconstant. The results of the investigation, presented inTechnical Xrote2313, show that increases in the rolling “–-and yaviing moments of inertia reduced the control- __lability of the model by increasing the time required toreach a given angle of bank and caused the flying quali-ties to become less desirable. The study also showedthat, as moment-of-inertia increased, the oscillatorystability generally demeaeed and flight behavior be-came progree9i’vely kss satisfactory.

A study has been made of methods for the evaluationof dynamic stability parameters from flight-test data.The ability to e-raluatetheso parameters by this tech-

12 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

nique will make it possible to obtain information onthe variation of these factors in the critical transonicrange. The results of this study are reported in Tech-nical Note 2340 and mathematical aids for the analysispresented in this paper are reported in Technical Note2341.

A summary of available methods for estimating sub-sonic dynamic lateral stability and airplane rwponsecharacteristics and for estimating the aerodynamic sta-bility derivatives required in these calculations has beenmade. The ~ults of this summary are presented inTechnical Note 24o9. This paper presents methods forobtaining time histories of lateral motions, period andclampingcharacteristic, and the lateral stability bound-mies, and also providw references to related experi-mental data. A brief discussion of the evaluation oftransonic and supersonic stability parameters is in-cluded.

A matrix method has been derived to determine thelongitudinal stability codlicients and frequency re-sponse characteristics of aircraft from arbitrary ma-neuvers. This method is presented in Technical N’ote2870 and can be applied to time history measurementsof such quantities as an@e of attack, pitching velocity,load factor, elevator angl~ and hinge moment to obtainover-ail coefficients. ‘iTith simple additional compu-tations, it can also be used to determine frequency re-sponse characteristics and may be applied to other prob-lems expressed by linear differential equations.

A theoretical investigation was macle using LaPlocetransformations to determine the effect of nonlinearstability derivatives on airplane lateral stability char-acteristics, with particular emphasis placed on snaking.The nordinearities assumed corresponded to the condi-tion where values of the directional stability and damp-ing-in-yaw derivatives are zero for small angles of side-slip. Results of this study are presented in TechnicalNote 2283 and indicate that under certain conditionsthe assumed nonlinearities caused a motion which haddifferent rtit”wof damping for large and snmll ampli-tudes and little damping at the small amplitudes.

Another theoretical study was made to determine theeffects of fuel motion on airplane dynamics. Results ofthis study are presented in Technical Note 2280. Inthis report, the general equations of motion for an air-plane with spherical fuel tanks are presented. The mo-tion of the fuel is approximated by the motion of solidpendulums. The analysis applies to fuel tanks of anyshape if the fuel motion can be represented in terms ofundamped harmonic oscillators. The study shows thatfuel motion may have an appreciable effect on the dy-namic behavior of an airplane.

balyticd and experimental investigations have beenmfide to determine the effects of wing interference on

vertical tuil effectiveness at low speeds. ‘llese studieshave been reported in Technical Notes 2332 and 2175.Comparisons of the estimated and experimental resultsindicate thnt the inclusion of a factor to account forwing interference effects provides agreement betweenthe experimental nnclestimated wdues of the tuil con-tribution to the rolling derivatives.

The lift and pitching moment producecl by angle ofattack, steady sttitepitchingj and constant vertical ac-celeration for a series of thin sweptbrwkstreamwise-tipwings of arbitrary sweep and taper hnve been deter-mined through the use of linearized supersonic flowtheory, The method of analysis nnd the results fromthe angle of attack and steady statepitching studies mepresented in Technical Note 2294 for a rnnge of super-sonic Mach numbers that allow the wing leading edgeto be subsonic and the trailing edge to be either super-sonic or subsonic. The method of analysis and studiesof the liti. and pitching moment due to constant verticalacceleration are reported in Technical Note 9815 for arange of supersonic Mach numbers for which the winglending edge is subsonic and the trtiiling edge super-sonic. Design charts are presented in both of these m-reportsthat permit rapid estimates of wing lift andpitching moment for given values of aspect rtitio, tttpw

ratio, Mach number, and leading-edge sw~ep.

Automatic StabiIity Studies

The application of automatic controls to the operatiouof aircraft complicates the analysis of aircraft dynam-ics. In. order to gain a more thorough knowledge ofthe factors involved in the automatic contro~ and sta-bilization of airplanes and missiles, research has beenintensified on means of solting current unil anticipatedproblems in this field.

A survey hns been made of various techniques used inanalysis of the stability and performance of nuto-matidly controlled aircraft. This survey deals withmethods commonly applied to the linear, continuouscontrol type of system ordinarily used in aircraft, rmdhas been published as Technical Note 2275.

An investigation was carried out to ewduate thesuitability of proposed methods for analyzing servo-mechanism systems incorporating feedback. Thisstudy is clescribed in Technical Note 2373 and dealswith an extension of frequency response techniques forthe analysis of an rmtopilot-aircraft combination, Thispaper contains comparisons between experimental dat:~and results obtained by the use of the practicnl methodsof calculation which were developed.

An experimental investigation was conducted to de-termine the response chamcteristics of four nirplaneconfigmmtions employing an autopilot sensitive to yfLvr-ing mcelemt ion. The results of this study we pre

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REPORT NATIONAL ADVISORY COMMITTEE FOR AEROXA_CS 13

sented in Technical Note 9395 and show that predictionsbased on the assumed autopilot characteristics did notagree with experimental data because the assumptionsdid not satisfuctorily approximate the frequency re-sponse characteristic of the autopilot.

A theoretical method was derived for determining thecontrol gem-in-~ and time lags necessary for a speofieddamping of the lateral motions of an aircraft equippedwith an autopilot. The method was applied to a typicalairplane equipped with an autopilot which deflects therudder in proportion to ~awing angular acceleration.The results of this study, presented in Technical Note2307, indicate that the types of motion predicted forthis airplane-autopilot system by the deri~ed methodme in good a~eement -withthose obtained by a step-by-step method.

Research on Controls

Theoreticrd and experimental research on the effectsof numerous control design variables on the characta-istice of contrcds has been continued during the past~ear.

In one theoretical study, an analysis was made of theeffects of sweep, aspect ratio, taper ratio, and Machnumber on the characteristics of inboard trailing-edgeflaps at supersonic speeds. This study considere caseswhere the Mnch lines lie behind the lead~m and trail-ing edges of the flap. Design charts developed fromthe analysis and presented in Technical Note 5k205en-able a rapid estinmtion to be made of the character-istics due to deflection for control surfaces for whichthe Mach lines from the flap tips do not intersect on thecontrcd surface.

In another theoretical analysis, supersonic controlcharacteristics were determined through the use ofexisting conical-flow theory. Thie analysis npplies toa broad range of trailing-edge control contlggationshaving supersonic edges and covers such variables aswing aspect ratio, taper ratio, sweep and control loca-tion. The results of this study, presented in TechnicalNote 25221,are in the form of equations and charts fromwhich Iift: pitching-moment, rolling-moment, andhinge-moment coeficimts may be determined.

The stability and control characteristics of wings oftrapezoidal planform were investigated by means ofLinearizedsupersonic theory to determine the charncter-istica of rarious wing-flap combinations. Expr&onsfor the stability characteristics were derived by treat-ing tie conflation as a complete wing, and the con-trol characteristics -were determined by treating it asu rectangular wing -withhalf-delta tip flaps. The re-sults, reported in Technical Note 2336, were cmmparedwith corresponding results for several other wing-flapcombinations and it was found that, of the wings con-

sidered, a triangular wing with either halfdelta tipflaps or traihng-eclge cent.rolsexhibited the most favor-able characteristics

& part of the general NACA program to investigatethe applicability of various types of ]atemd control de-vices to -wingssuitable for h@h-speed flight, an experi-mental investigation was conducted in the Langley 300-mph 7-by 10-foot tunnel to determine the effect of aspectratio on the lateral control characteristics of a series ofuntapered? Wept, low-aspect-ratio wings equippedwith continuous type retractable spoiler aiIerons. Ones.-weptwing was included in the study for purposes ofcomparison, and, in addition to being equipped with thecontinuous type spofler, -was also inwsstigated whenequipped -with a stepped or segmented spoiler aileron.The results of the study, reported in Technical Note2347, indicate that for the unswept -i-ringscontinuousspoiler ai.Ieronsbecame progressively more effective inproducing ro~ as wing aspect ratio was increased. Thecontinuous spoiler aileron was lesseffective on the s-iieptwing than on a straight .-wingof comparable aspect ratio.On the s-weptwing it was found that the effectivenessofthe continuous spoiler generally increased as the spoilerwas moved progre~ively inboard, vrlde the oppositewas true for the stepped spoiler.

Au experimental investigation was conducted in theb“ley 3oo-mph 7- by 10-foot turn-d to determine thelaterul control characteristics of an untapered semispanwing having either 0° or 45° of sweep and equipped witha plain unsealed aileron. The span and spanmise loca-tion of the aileron were wmied in order to determine theoptimum configuration for roI1ing effectiveness. Theredts of this inwsti=wtion, reported in TechnicalX’otes 2199 and X16, indicate thxt for either the sweptor unswept wing, a given partial span aileron was mosteffectire in produci~w roll and in maintaining effective-ness over a large ang~eof atttickrm-ge when located onthe outboard portion of the wing. It -wasalso foundthat, although the rate of change of aileron hinge-moment coefficientwith angle of attack could not tdwaysbe stdisfactorily predicted for the swept wing, existingemptilcal methods for predicting the rate of chan~fyofrolling moment coetEcient and aileron hinge-momentcoefficient with aileron deflection provided satisfactoryn=greementwith the experimental results for both thestraight and swept wings.

In order to determine the effect of aspect ratio on thelow-speed lateral control characteristics of low-aspect-ratio winam,a series of four unswep~ untapered wingswith aspect ratios from 1 to 6 was investigated in theLangley 300-mph 7-by 10-foot tunnel. The wings wereequipped with plain sealed ailerons of various spansloeated at several span.wise stations. The results ofthis study are presented in Technical Note 9348 and

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14 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

show thut the variation of aileron effectiveness withaspect ratio could not be accurately predictad for alIailreon spans by any of the theoretical methods utilizedin this investigation.

Studies of Damping Derivativea

Theoretical and experimental studies have been ex-tended in the past year to develop methods for thereliaMe evalucttionof clamping derivatives in all speedranges.

One theoretical method, clescribedin Technical Note2197, was developed for calculating the pressure dis-tribution and damping in pitch at supersonic Machnumbers for thin swept wings having subsonic ei@s.The method consists of the calculation of a basic pres-sure distribution and the correction of this distributionto account for the effects of the subsonic trailing edgesand tips. These data are then used to determine theclamping-in-pitch characteristic.

Technical Note 2285 presents rm evaluation of thesupersonic damping in roll of cruciform delta wings bymeans of linearized theory. Both subsonic and super-sonic leading edges were considered. The effect ofincreasing the number of wing panels from four to anarbitmry number under the restriction of low-aspectratio was determined, and the damping for an infinitenumber of wing panels -wasevalunted without restric-tion as to mpect ratio or Mach number. A similar theo-retical study is reported in Technical Note 2270 inwhich the theory of slender wi~~s was used to deter-mine the characteristics in roll of slender cruciformwings. This analysis shows that, for the cruciformwing, the damping-in-roll is considerably greater thanthat of a phme wing having the same aspect ratio andthat the rolling effectiveness is less than that of n planewing.

Experimented studies of damping derivatives havebeen carried out in the rolling and curved flow facilitiesof the Langley stability tunnel. One investigation wasconducted to determine the effects of horizontal taillocation on the low-speed static longitudinal stabilityand damping in pitch of a model with 45° swept wingsand tail. The results,published in Technical Note 2381,indicate that at high angles of attack, lowering thehorizontal tail increased the static longitudinal stabilityand decreased the damping in pitch. A related inves-tigation is reported in Technical Note 2382. In thisstucly,horizontal tail size and tail length are variables.The study shows that the contribution of the horizontcdtail to static longitudinal stability was directly relatedto tail size and length, while damping in pitch -wasre-lated to tail size and the square of the tail length,

&other investigation was conducted in the Langleystability tunnel to determine the effect of vertical tail

area and tail length on the yawing stability of a modelwith a s-weptwing. Technical Note 2358 contains theresults of this study, which indicate that the effects ofwing-fuselage interference for the miclwing configura-tion studieclwere small ovar most of the cmgle-of-tittackrange, Large interference effects on the vertical tuileffectivenesswere apparently produced by both the wingancl fusehge at modemte and high angles of attack, butbecause these effects tended to cancel each other, thegross effects were small.

Investigation of Flying Qualities

The increasing operational speeds of current tmd pro- -posed aircraft have aggravated the problems invo~veclin defining and achieving flying qualities compat iblcwith safety, performance , and piloting requirements.Research to isolate the effects of numerous design pa-rameters on flying qualities has continued to receiveattention.

Two design facto~s which can significantly affect theflying qualiiies of an tiirplmnemu the wing airfoil sec-tion and the type of lateral-control device employed.To determine the effects of one of these design variableson the flying qualities of an airplane model, cm investi-gation was conducted in the Langley free-flight tunnelto detern~inethe effectsof round and sharp le:~ding-edgeairfoil sections on the dynamic lateral stability and con-trol characteristics. Two models viereused in the study,one representative of a current fighter airplane withrespect to inertia characteristics and the other repre-sentative of a possible future design in which mass isconcentrated rdong the fuselage. The results of the in-vestigation, reported in Technical Note 2219, indicatethat airfoil section has no apparent effect on the flyingqwdities of the model with high fuseh~geinertia. Thenormal inertia model when equippe.clwith the wing lMv-ing u rouncl-nose airfoil section exhibited adverse yaw-ing during aileron rolls which increased with decreasesin directional stability. This same model, however, ex-hibited no adverse yawing when fitted with the winghaving a sharp-nose airfoil, even at low vulues ofdirectional stability. This difference in flying chamc-terstics is attribnteclto the adverse yawing moment dueto rolling of the rouncl-nos8 wing, which on the othermoclelis apparently maskedby the high fuselage inertin,

Another investigation was conducted in the Lm@eyfree-flight tunnel to compare the dynamic lateml-con-trol characteristics of stepped plug ailerons with thoseof conventional plain flup tii]erons. The model employedin this study hacl a low-aspect-ratio swept wing equip-ped with full span flaps. The results of the investi-gation, published in Technical Note 2247, show thatwhen the lateral stability characteristics were satis-factory the controllability of the model was better with

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REPORTNATIONALADVLSOEYCOMMITTEE FOR AERONAUTICS .--15

pht.g ailerons alone than with conventional aileronsdone because the 10SSof rolling effectiveness due to theadverse yaw associated with the flap aileron vm.smoreobjectionable than the lag associated with the plug aikr-ons. For conditions of low dynamic lateral stability,the con-rentional ailerons alone provided better control-lability than either plug ailerons alone or a combinationof flap uilerons and rudder. Although the time lag ofthe plug ailerons was excw=ire according to existingfly~m qualities requirements, the pilot considered thecontrollability of the model to be satisfactory.

The improvement.of passenger comfort in airplanes,through a reclnction of accekratious caused by roughair: has become of greater interest as airplane opera-tional speeds have increassd. One method which hasbeen suggested for providing increased comfort in h.igh-speed airphmes is to have the wing flaps operated byan angle-of-tittack or acceleration-sensing device insuch n manner as to reduce accelerations due.to gusts.A theoretical study of such a system has been madeand is reported in Technical Note !2416. The resultsof the study show that flaps with characteristics sim-ilar to those of con~entional landing flaps me unsuit-:lhle for acceleration alletiat ion because of airplanepitching motions resulting from flap deflection. Theanalysis indicates that the flaps shouId produce zeropitching moment about the wing aerodynamic centerand downwash at the tail in the opposite direction fromthat normally expected in order to be satisfactory forthis application. Various means of achieving thesecharacteristics are suggested, and it is shown that flapspossessing these desirable characteristics wordd be ef-fective in reducing accelerations in rough air whencombined with an an@eof -attack or acceleration-sens-ing device.

In the previous study no attempt -wasmade to con-sider the practical probkms involved in the designof a mechanism for acceleration alleviation. To helpevaluate one of these problems, an experimental in-vestigation was made to determine the ability of a wtnemounted ahead of the nose of an airplane to gi~e anindication of the awwage angle of attack over the entireviing span during flight through rough air. The re-sults of this investigation are presented in TechnicalXote 2415 and show that the device gives a sufficient.lyaccurate indication of average ang~eof attack over thewing span to allow its use in an acceleration alleviationsystem.

spinning Investigations

The spin and recovery characteristics of airplaneswe dependent on many aerodynamic and structural de-sign parameters. In order to provide the designer withinformation on vihioh of these parameters may be ofprimary importance to the recoverv characteristics of

any particnIar aircraft cor&guration~ research on theproblems of spinuing hm continued in the Langley20-foot free-spinning tunnel.

One investigation was conducted to determine theeffects of mass and dimem=ionalradiations on the spinand reco~e~ characteristics of a model representativeof current four-pIace light airphmes. The results,which are reported in Technical h“ote 2352+ indicatethat satisftictory recovery characteristics could be ob-tained for all of the mass distributions studied pro-videcl that the proper sequence of control morementsfor recovery was foIlovred. It was also found that un-less the rudder can be made to float a=-inst the spin,reco-reryby releasing controls maybe difiicult to achieveunless the ele-iator floats below neutraL Other require-ments for spin recovery set forth in current regulationscgulcl probably be met for the model arrangements in-vestigated by restricting center-of-=mavity location andproviding a high value of tail damping.

Because a previous study had indicated that a horn-balancecl rudder might possess the desirable charac- ..__teristic of floating against the spin, an experimental in-vestigation -was undertaken to determine the floatingcharacteristics of full-length plain and horn-balancedrudders cluring rotary tests at spinning attitudes of amodel of n typical lo-w-wing light airplane. The effects ._of the horizontal tail and -wing on the rudder floati~a

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charticteristic~ were also determined. The results ofthis investigation, reported in Technical fi’ote 2359, in-dicate that for this codguration the rudder was in thewake of the stalled wing and oscillated violently forhigh spinning angles of attack. At lower angles of at-tack, or for the case in which the tail vim outside the-wakeof the stalled wing, the horn-balanced rudder hadmore desirable floatirg characteristics than a plainrnddert although neither would fulfill the floati~mde-flection requirements for control-free spin recovery.

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AIRCILWT PROPELLERS

In the field of propeller vibration. Technictil Xote230S has been published in centinuation of the investi-gatiou of first-order propeller ~ibration on a twin-engine. stmight-wing airplane in the Ames 40- bySO-foot tmmel. A procedure has been derelopecl forcomputing the flom field at the propeller phlne to asuflicieut degree of accuracy to permit satisfactory cal-culation of the propeller ribratory stresses. In theprocedure, nccount is tnken of the upmwl contribu-tions of the wing. fusdage: and nacelles and theirmutual interference effects. The anal@s shows thatthe nacelle caused an unezcpectedIylarge effect whic&if ignored, could readily cause disagreement betweenthe mn=-itucle of computed and measured vibratorystresees.

16 REPORTNATIONALADVISORYCOMkUTTEEFOR AERONAUTICS

In another propeller vibration investigation, theexisting analysis applicable to the prediction of first-order exciting forces for the straight-wing propellercase has been extended to inclucle the swept-wing pro-peller combination. With the aid of the straight-wingzmalysi~a typical swept-wing propeller-driven airplanOdesign has been studied to examine the magnitude ofthe once per revolution exciting forces which couldexist. It has been found that in addition to the usurdexciting forces, a new and relatively important one isadded where a swept wing is used; this results from therelative fore and aft movement of the propeller bladewith respect to the leading edge of tha wing which isswept with respect to the propeller plane of rotation.It was found further that the effects of Mach numberare such as to reduce the magnitude. of the once-per-revolution exciting forces.

sEAPIJmEsHydrodynamic studies have continued in the Lang-

ley tanks to provide basic and design data for thedevelopment of water-based airplanes.

One study reported in Technical Note 2297 investi-gated the use of high angles of dead rise on high-length-beam-ratio flying-boat hulls as a means for reducingwater loads encountered during rough-water operation.An increase in angle of dead rise from 20° to 40° in-creasedthe take-off stability and substantially improvedthe spray characteristics of a high-length-beam ratiohull. A expectwl decrease intake-oil performance wasevidenced by increases in take-off time and distance of25 and 30 percent, respective~y. The over-all rough-water landing behavior was improved; the maximumvertical and angular accelerations were reduced ap-proximately 55 and SOpercent, respectively. The re-duction in vertical acceleration was in good agreementwith that predicted by impact theory.

ROTARY WING AIRCRAFI’

Based on the resultsof flight investigations of severalsingle-rotor helicopters, preliminary qualitative re-quirements for satisfactory flying and handling quali-ties of helicopters have been establklmd. Progress indesigning helicopters to meet these requirements, how-ever, has been handicapped by the need for a methodpermitting sufficiently accurate prediction of the fly-ing qualities of a helicopter at the design stage. Tohelp fiIl this need, cmisting rotor theory, accurate forthe calculation of rotor performance and blade motion,has been extended (Technical Note 2809) to permit theprediction of those rotor characteristics that influencethe flying qualities. Variation of the longitudinal de-rivatives of rotor resultant force, rotor pitching mo-

ment, and rotor torque with operating parameters suchas rotor angle of attac@ collective pitch, forward speed,and rotational speed may be determined. The usualsimplifying assumption that the rotor resultant forcevector is perpendicular to the rotor tip path plane isshown by the resulte of this theory to lead in manycases to grossly incorrect longitudinal stability deriva-tives. The theory aIso indicates that the increase inrotor load factor with an incremental increase in angleof attack is approximately linear with increasing for-ward speed. This is in contrast to the airplane wherethe increase is as the square of the forward velocity.

Increases in tbe forward speed of helicopters are ex-pected to require increases in rotor tip speeds in orderto avoid excessive tip stalling on the retreating Made.At tip speeds within the transonic range the rotor wiIlsuffer some performance loss due to compressibility. Inorder to gain an insight into the mabmitudeof this com-pressibility-induced performance 10SSand to furnish acheck on theoretical methods of estimating the loss, twoconventional fuWscale rotors? one having linear twistand the other untwisted, have been tested to tip speedsup to 77o feet per second on the Lan.gley helicopter testtower. The resultsof this study, reported in TechnicalNote 227’7, show that both rotors suffered increasingcompressibility losses as the tip speed increased to themaximum epeed studied. Linear twist delnyed theonset of compressibility losses. For the blades investi-gated good agreement was obtained between the meas-ured and predicted drag-divergence Mach number.

As part of a general investigation of the aerod-y-namic characteristics of various multirotor con.6_gura-tions, an investigation to determine the static-thrustperformance of two full-scale coaxial helicopter rotorshas been conducted in the Langley full-scale tunnel.One coaxial rotor vws equippecl with blades tapered inboth planform and thickness and the other with bladestapered in thickness only. The result~ presented inTechnical Note 2318, show the hovering perforrmmce ofeach rotor in the coaxial configuration and with theripper rotor removed. The effect of application of yawcontrol on the hovering performance of the coaxial con-figurations is also presented. A comparison of mens-ured and predicted hovering performance is included.

As a part of the investigation of multirotor config-urations a study was made of the air-flow patternsthrough small ecde single, coaxial, and tandem rotormodel% The balsa-dust technique of air-flow visuali-zation ivas employed. The photographic results, pre-sented in Technical Note 2220, provide a qualitativeinterpretation of the transient and steady-state flowIthrough the rotors.

A theoretical study of the rigid-body oscilltitions in ‘-hovering of helicopter rotor blades has been made by

REPORT NATIONAL ADWSORY COitlh~TTEE FOR AERONAUTICS 17

the Polytechnic Institute of Brooklyn under NACAsponsorship. The study, presented in Technical Note2226, includes a determination of the rigid-body fre-quency and damping characteristics of the coupled flap-ping and lagging oscillations of helicopter bIades onvdlich the lagging h@e axis is o&t from the flappinghinge axis and both hinges are inclined. The effect ofoffset of the flappirqghinge axis from the axis of rota-tion of the rotor is ak.o considered.

The anaIysis and numerical examples indicate thatsignificant increases in the damping of the laggingmotions! which ordinarily border on instability, cm beobtained by suitable inclinations of the hinge +particularly the lag@g axis, Otketting the flappingand lagging hinge axis alsa increases the natural hg-ging frequency.

UPPER ATMOSPHERE RESEARCH

in Technical Note 1200with the observed free periods ofmcillat ion of the atmosphere has codinued. Tech-nical Notes 2i209and 22314present the results of a con-tinued study of atmospheric tides by the Institute forAdvanced Study, under NACA sponsorship. The in-wstia@ions indicate that certain simplifying amunp-tions mude in the development of the basic ocean tide

equations iuvaIidat es these relations for application to

the study of atmospheric tides. A method for includ-

ing the previously neglected terms in the tidal equations

has been outline~ and two atmospheres of different tem-perature distribution htire been studied.

A review by the Subcommittee on the Upper .-tmos-phere of experimenhd information on the characteris-tics of the atmosphere from sea level to a height of 32kilometers has indicated that the standard atmospheretentatire]y proposed in Technical Note 1200 represents

The study of the compatibilityy of the tentative stand- to a satisfactory degree of accuracy the charac&isticsard atmospheric temperature distribution as set forth of the atmosphere within this height r~me.

POWER PLANTS FOR AIRCRAFT

With the ever-increasing trend for aircraft operationat higher altitudes and higher Mach numbers there hasarisen a multitude of complex power plant prob~ems.?3f&ient diffusers at high Mach munber, greater air ffovihandling ability of compressors, increased combustionefficiencies at high altitudes without blowo~lt or insta-bility, increased turbine inlet gas temperatures, reduc-tion of strategic material content, increased thrust aug-mentation with afterburners, and the orer-a.11enginecontrol and component matching require extensivepower plant rwearch. For the purpose of obtaining themost efficientoperation of each part of the power plant,these problems hare been approached thro~mh theoret-ical and experimental investigations. Power plants,such as the turboje~ the turbopropeIIer, the ram je~ therocket, and combinations of these engines utiliziigchernicrdand nuclear fuek are currently under in-resti-gation. As a result of this research improved subsanicand supersonic operation of the interceptor, the long-range bomber, and the guided missile can be expected.

NAC.A efforts in the aircraft-propulsion field havebeen assisted by the Committee on Power Plants forAircraft and iti seven subcommittees. The foI.Iowingdiscussion is lin~itedto unclassified research.

AIRCRAFT FUELS RESEARCH

power plants. Concurrently with research on futurefuels it has been necessary to maintain a high degree ofemphasis on current aircraft fuels in order to assuretheavailability of satisfactory fueIs in the event of anemergency. The greatest problem in the current air-craft-fuel prcgram is the formalization of a sound fuelspecification that will assuremaximum availability andsuperior performance.

$$mtheais and Amdpia

Bec~use many of the aircraft considered for the fu-ture are -rohnnel.mited with respect to fuel storage,hydrocarbon synthesis has been directed primarily to-ward fueIs that -wilIrelease high energy per unit vol-ume and consequently permit the attainment of desiredflight range. Fuels of this type are not readily availableeven in small quantities required for research studies.For this reason synthesis facilities of the NACA arein continuous operation isolating pure highdensityhydrocarbons to be used in engine-performance studies.

During the paaa year the synthesis and purificationof some of the high-density hydrocarbons have beenkscribecl in Teclmical Notes W30 and 2260. Nineteencompounds were isolated and those having satisfactoryphyaicrd and chemical properties will ultimately be

—

Intensive effort has been applied in the past yet-wto evaluated in typicaI turbojet<ornbustor performancethe field of aircraft-fuel research with consideration be- investigations. The synthesis projects are planned ining given to current aircraft fuels as well as fuek+of the an orclerly manner to permit the analysis of correla-fut me. .is might be expected, investigations conducted tions between rnolecular structurc and properties. Bysince the advent of jet propulsion have gradua]ly led this process considerable time and money is saved intoward the de-relopment of special fuels for future that an exmnination of the correlation till inclicate

18 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

-whichmolecular structureshave obvious disaclvantages,thus obviating costly and tedious synthesis.

In addition to high-density hydrocarbons, othercompounds have been synthesized for investigation aspowible fuel components to provide greater combustionstability over wide operating ranges and better ignitioncharacteristics. Hydrocarbons such as cyclopropanederivatives me being prepared for study of the effect ofmolecular structure on rates of flame propagation. Re-sults of the synthesis of ten cyclopropane hydrocarbonshave been reported in Technical Notes 2258, 9259, and2398. The ten hydrocarbons were obtained in highpurity for the first time md physical constants andinfrared spectra are given in the cited references. Syn-thesis procedures were developed, and physical proper-ties and heats of combustion were determined for fouralkylsilanw. This was the first experimental deter-mination of heats of combustion for thew compounds.

In the course of conducting synthesis projects, occa-sional results of general interest with regard to experi-mental technique are obtained. When this occu~ thedata are published for the information and use of vari-ous synthesis laboratories. A study of this nature hasrecently been reported in Technical 7Sote2342, In thispublication an evaluation of packed distillation columnsused by the NACA is described.

Aside from the determination of physical propertiesof synthesized materials, the NACA analytical labora-tories participate in studiesto improve methods of anal-ysis of fuels, Particular attention has been given to theanalytical procedure for cleterminationof aromatic andoleiinic hydrocarbons in wide-boiling petroleum f rac-tions. These hydrocarbon classes are known to be sig-nificant in relation to engine performance anclthereforethe quantities present in n given fuel stock must be ac-curately known, A procedure for the determination ofaromatics cmd olefins has been deveIoped which is ap-plicable to the determination of aromatics and olefinsin petroleum stocks with final boiling points below 600°F. Accuracies of 1 percent are attained with analysistimes of less than 8 hours.

FueIe Performance Evaluation

The problem of relating easily measured hydrocarbonfuel properties to el]gine performance has received con-siderable attention sincg the advent of jet propulsion.The object of this research is to permit the predictionof engine performance of fuels from fuel propertiesthat may be determined with relative ease. Combustionproperties of interest are spontaneous ignition tempera-ture, flame velocities, and inflammability limits.

Spontaneous ignition temperatures for 109 hydrocar-bons and commercial fuels have been determined by acrucible method. From these data trends in the varia-

tion of ignition temperature with molecuhm structurehave been established. The performance of ten of themfuels has been studied in n single tubular combust.w.

During the past year flame-velocity studies were madeof 37 pure hydrocarbons. The classes of conlpouncL~examined were alkanes, alkenw, alkynes, benzene, andcyclohemme. The results of this study indicated thatthe flame velocities of the normal alkanes were the stimeexcept for methane which had a velocity about 16 per-cent lower than the allmnesof higher molecular weight.The alkenes and the alkynes had velocities somewhuthigher than those of the alkanes,particuhwly in the IOWmolecular weight range. The results of this investiga-tion have been published in the Journal of the AmericanChemical Society (vol. 73, No. 1, January 1951).

The flame velocity investigation was later extendedto include the alkadienes. Ten compounds in this classwere studied and it was found that the flame velocitieswere higher than those of the alkanes and approxi-mately equal to the flame velocitie9 of the alkynes inves-tigated. Performance of certain fuels in these classesof compounds are being studied in a single tubular com-buster.

The flame-velocity data accumulated in the foregoinginvestigations have been used as the basis for correla-tions between molecular structure and flame velocity.One such correlation indicated that the maximum flamevelocity is a function of the concentrations of the vari-ous types of carbon-hydrogen bonds in the inflammablemixture. From this correlation the maximum flamevelocities were crdculated for 34 hydrocarbons. Theaverage difference between the calculated and observed.flame velocity is less than 2 percent. The results of thisanalysis were published in the Journal of the AmericanChemical Society (vo1. 7’3, No. 4, April 1951).

As another part of this research an investigation isbeing conducted to determine the inflammability limitsof pure hydrocarbon-air mixtures at different pressures.The limits were determined for 17 pure normalparaffis, branched paraffins,and mono-olefins. It wasfound that the lean inflammability limits were aboutthe same for all of the fuels, however, the rich limitsincreased markedly with increased molcculm weight.

The tendency of certain fuels to deposit carbon incombustors thereby lowering performmce and causingmechanical dficulties continues as one of the more im-portant problems for research. Brief investigationshave been made of several fuels which contain com-ponents allowable in the jet fuel specification but whichappear marginal from a carbon deposition standpoint.A study of these fuels with several current turbojetengines is intended to show how fuel specification andcombu.stor design may be compromised for lmst per-formance and maximum fuel availability.

-.

REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS 19

COMBUSTION RESEARCH

Because aircraft engines must produce enormouspower from a small package, it. is axiomatic that thecombustion problem is to release tremendous quantitiesof heat energy from the fuel in a small vohune and ina short space of time. NACA research on combustionis directed at obtaining an understanding of the basicphysics ancl chemistry behind the phenomena in-rol-redin combustion and demonstrating how these phenomenacan be put to use to meet all the requirements of flight.Basic studies are made on detaiIed problems of com-bustion such as evaporation, ignition, flame propaga-tion hits, flame velocity, flame quenching, with vari-abks such as composition, pressure? tempe~tu% ~e-

locity, and turbulence. Studies on applying these datainvolve (a) systematic studies of the &ect of operatingvariable and design variables on engine performancesuch as combustion eiiiciency, altitude operational lim-its. smoke and carbon formation, pressure drop and tem-perature profle, and (b) attempts to correlate basiccombustion laws with enbgineperformance.

Fundamentals of Combustion

To gain an insight into the problem of combustionstability at high altitudes, a study has been made of thechemical and physical factors affecting the inflamma-bility limits at different preasur=. The results of theinvestigation of chemical factors were discussed underthe fueIs reswrch pro~am. .ti imestigation was alsomade of the etlects of wails on inflammability Limits.The results indicated that the minimum pressure forflame propagation increased with diminishing tubediameter (greater relati-re -wall area). In connectionwith the inflammability Iimitaof fue~ an investigationwas conducted to determine the combustion efficienciesof hydrocarbon-air systemsat reduced pressures. Withquiescent fuel-air mixtures and with small difisionflames, combustion efficiencke cke to 100 percent wereobtained nt presssres much lower than those found inturbojet combustors at high altitude; in general, &-ciencies were high at presmes approaching the Iimit-ing values for inflammation.

SewraI projects are in progress to ascertain the basicmechanism of flnme propagation in order to gain in-sight into the actual combustion process that occurs inan enggne. The.ssstudies supplement the studies of the

effect of hydrocarbon structure on flame vekwity re-ported in the fuels program. In one phase of this work,the effect of initial mixture temperature on flame~elocit~ -mIsevaluated. The first of thesestudies (Tech-nicid Note 2170) evahmted the flame =uAcities andblow-off limits of propane-air flames. These studies

-werelater extended to include methane-air anclethylene-air flames (TecbnicaI If70te2374). As a resuIt of theMprojects, equations were developed to permit the eet.ima-tion of flame mlocity at -rarious initial mixture temper-atures in the range of 34° to 344° C.

In order to achieve a better understanding of thecauea of flame propagation, Several stufies have kenmade of the effect of free radicals on flame propabfption.Innsmuch as hydrogen difFusesmore readily than other

.

radicals in a flame, it has been suggested by past in-vestigators that the rate of flame propagation is relatedto the hydrogen-atom concentration in the flame zone.AU evaluation of this theory was made by adding lightwater and heavy water to mixtures of carbon monoxide ..and air and measuring the flame ~elocitiea. R was rea- ..—soned that hydrogen from heavy water would diffuse1sssrapidly than that from light mater; consequently, alower flame -rehcity would result. Measurementsof the .. .flame velocities substantiated this reasoning.

In an analysis of flame-velocity data for 35 purehydrocarbons, it was conchlded that the rnaximw fl~rne

~elocities were consistent with the active rmlical theoryof flame propagation. Only one pure hydrocarbon,ethylene, was found to be inconsistent with the theory.This analysis was published in the Journal of theAmerican Chemical Society (-rol. 73, No. 1, January1951).

In connection with frame-Telocity investigations, amethod for determiningg the distribution of huninous .—emitters in a Bunsen flame was found and is describedin Technical A’ote 2246. As an examp~eof the applica-tion of this method, an intensity distribution in a Bun-sen cone image resulting from the free radical Cz radia-tion was analyzed.

In order to correlate the fkun~propagation rehcit.iee –=of a burner with the lod turbukmcs intensity in the .=_flow, quantitative turbulence data are needed. Suchdata hare been obtained from an irmessigation, the ___results of which are presented in Technical N’ote .2361.Dtita vrer~ obtained for turbuhmt-~elocity-fluctuationcomponents and rnezm-~elocity distributions in a sub-sonic jet iawing from a pipe in which fully de~elopedtnrbulent flow vws established. It was found that at thejet exit the axial-fluctuation-velocity component wasabout 2’.5times as great-as the radial component at thepipe center line. Near the pipe -walllthe axiaI-fluctua-tion-relocity component was about three or four timesas great asthe radial component. The axial componentsof the turbulent fluctuation velocities diminished rap-idIy downstream of the pipe mall, whereas the radialcomponents were practically constant so that the axialand radial components npprcmcheda condition of equalmagfitude with increasi~v distance from the pipe exit

20 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

LUBRICATION AND WEAR

Fundamentals of Friction and Wear

The current trend in the selection of aircraft-power-phmt lubricants is to materials of low viscosity. Theprimary reason for this is to meet low temperatureoperating and starting requirements. It may be ex-pected that such usage will lead to difficulties becauseof the low load capacities obtained with the light oils.One means of compensating for the reduced load caprtc-ity is by the usc of EP (extreme pressure) additives.One of the objectives of lubrication and wear researchis to determine for surfaces lubricated with EP addi-tives whether a change in chemical reactivity couldappreciably affect the rate of production of a pro-tective fdm uncl thus appreci~bly affect the criticalsliding velocity at ,which surface -welding begins.Among the additives under study are benzyl chlorideC,H,CH,C1, p-dic.hlorobenzene C,H,Cl,, free sulfur S,benzyl disulficle (C,H.CH,) ,S,, and phenyl monosufide(C,H,),S, at sliding velocities from 75 to 7,OOOfeet perminute and initicd Hertz surface stressesup to 194,000p. s. i. (Technical Note 2144). Results indicate thathigher critical sliding vekwities may be obtained -withadditives whose active atoms have the greatest chemicalreactivity. The study showed that the factor of activ-ity of the individual active atoms w-asmore importantthan the number of such atoms available for reaction.

A further study of the eflect of additives on criticalsliding velocities involved the use of fatty acids (Tech-nical Note 2366). This investigation was conductedbecause it has been found that with an EP additivelubrication may be ineffective at high sliding velocitiesbecause a chemical reaction between the surfaces andthe additive to provide a lubricating film may not havetime to occur. Further, studies at low temperatureshave establishedthe point that with the fatty-acid xddi-tive, high contact temperatures or pressures are unnec-essary for the formation of an effective lubricati~o film.Studies have been completed of stearic acid as fin nddi-tive in cettine at sliding velocities up to 7,000 feet perminute on clean steel surfaces and surfaces coated withferric oxide Fe,O, (Technical Note 2366). The ex-periments indicate that the type of surface oxide andthe thickness of the oxide film are important in deter-mining the effectiveness of stearic acid as an additiwa

Most of the bearings employed in the turbine-typeaircraft power plants are roMng-contact bearings.Early service experience indicated that one of the prin-cipal sources of failure in bearings haa been lubricationfailures at the cage locating surface9 (retainer or sep-arator). These failures are due in main to the difficultyin obtaini~~ proper lubrication because of design con-

figurations and to %igh-temperature soaking” (above500° F.) of the turbine bearing after engine shut-clown.One meansof reducing the severity of the problem is toobtain a cage material having R leasertendency towardmetallic adhesion to steel under marginal conditions oflubrication than the currently used materials. SIidingfriction experiments have been made to obtain funda-mental comparative information on friction ancl wearproperties which are a general measure of adhesion(Technical Note 2384). The materials studied werebrawl bronze, beryllium copper, Monel, Nichrome V,24S-T aluminum, nodular iron, and gray cast iron atsliding velocities up to 18,000feet per minute. On thebasis of wear and resistance to welding only, the custirons were the most promising materials investigatedin that they showed the least wear and the least tendencyto surface failure when run dry. On the basis ofmechaniea~properties, the nodular iron is superior togray cast iron. Results obtained with bras%berylliumcopper, and aluminum indicate that these materials tirenot particularly suited for cages.

It has been observed that the running of piston rin~particularly nitrided cylinder barrels, induces the for-mation on the ring of a surface coating which haddifferent ancl, in some respects, superior propertiescompared with those of the bulk ring material. An in-vestigation has been completed, whose objective WM.todetermine to what extent these rubbing conditionscould have produced transfer of metal from the barrelto the ring (Technical Note 2271), The study con-cerneclitedf with metal transfer between nitrided stealof several hardnesaesand also between chromium platennclnitrided steel. The technique employed consistedof making one of two rubbing surfaces mdioact ive, car-rying out rcfriction test and then examining the othersurface for signs of radioactivity, The effects on nmte-rial transfer of, load, speed, clistante of truvel, repeatedtravel over the same path, hardness of the moving sur-face, anclthe type of chromium plate were investigated.In the case of all materials studied, there was an ob-servable tu-nountof transfer. The amount of transferwns roughly proportional to the distnnce traveled andwas independent of vihether this travel was repeated anumber of times over the same track or was continu-ously over fresh surface, In addition, the amount oftransfer for a given distance of truvel was constantover a range of low speeds, but started to decrease athigher speeds. This indicates that a possible pretreat-ment,to obtain a desirable surface layer might consistof running rings in a spec.itilcylincler having walls ofselectecl composition and controlled hardness to givesurface coatings highly improved characteristics in amiuimurnlength of time.

REPORT iSATIOX.4L ADVISORY COMMITTEE FOR AEROXAUTTCS 21

Fretting

Fretting is defined as the surface failure that m:iyoccur when closely fitting metaI surfilces unclergo slightreh~tive motion. Recent research condncted by theX.ICA indicates that fretting is the result of localizedor very concentrated friction phenomenn. Adhesion isbelieved to be the primm-y friction phenomenon in-volved in that it muses the removal of finely diviclecloxicliz~lblemetal. Other phenomem[. such M the rub-bing off of oxide films, -welding from frictional heut,and nbrasion. undoubtedly contribute to surface de-struction. The effectiveness of the intermetallic com-pound molybdenum disulfide (MoS,) as a frettinginhibitor ras studied: utilizing a steel ball, vibrated incontact with gks flats at 120 cycles per second, anamplitude of 0.001inch, and a normal load of 0.2 pound(Technics] Note 2180). A coating of dry molybdenumdisuIilde bonded to steel by rubbing a mixture of mo-lybdenum disrdfide and syrup in intimate contact withclean steel at elevated temperatures pro~ed the mostelfective. This conti~a delayed the onset of frettingto 28,000,000cycles in contrast to less than 30 cycles fora clean uncoated steel

Bearing Research

A clepencIablebearing to carry a radial load at ex-treme speeds and at high ambient temperatures is de-sired for use as the turbine-support bearing in aircraftgas turbines vihere the gravity lends are usually under1$)00 pouncls and the DN (diameter in millimetersmultiplied by rerolutiona per minute) values are ashigh as 1X 10’. To develop such a bearing it is neces-sary to know the operating characteristics and limita-tions of c.onventionmlrolling-contnct bearings at highspeeds and how these characteristics and limitationsmay be improved and extended by such means as im-proved lubrication methods and design moditlcations.A study has been completed utiIizing three types ofbearings to determine experimentally the operatingchar~cteristics of conventional cylintilcal roller bear-ings at high speeds at DhT values from 0.3X 10E to1.65X 10’ and static radial loads from ‘7 to 1,613pounds ,with circulatory oil feed (Technical Note212S). The operating temperatures of the bearingswere found to differ most appreciably in the lo-iv-loadhigh-speed rrmge where the roller-riding cage-typebearing exhibited signi&mtly lower operating tem-peratures than the om+ and two-piece inner-race-rid-ing cage+pe bearings. However, the operation ofthe roller-riding bearings -was considerably rougherthan that of the inner-race-rid@ bearings and theyshowed prohibitive cage and rcdler wet-m.

A continuation of the study outlined above vimundertaken to compam and to evaluate the effects of oil-

in]et location, jet angle, and jet velocity on outer- andinner-race bearing temperatures for single-jet lubrica-tion over a wide range of variables (Technical Note9216). The effect of oil flows of 0.6 to 12.9 pounds perminute and oil irdet velocities of 13 to 200 feet persecond -were studied utilizing a onepiece inner-race-ridhqg brass cage bearing o~er a load range of 113to 36Spounds and DN wdues of 0.3X 1(Pto 1.43X I@. For the ‘ “–conditions studied, the inner- and outer-race tempera-tures were found to be at a minimum when the oil vimclirected at the cage-locatingj surface perpendicularto the bearing face. A mathematical correlationbased on heat transfer considerations was obtainedsuch that for a gi~en operat~m condition a representa-ti-resingle straight line resulted regardless of whetherthe bear@o spee~ oil flow, or jet diameter was varied.

COMPRESSOR AND Tum3mERESEARCHCompressor Research

Both high-speed and long-rsmge aircraft utilizinggas-turbine power plants require light compact com-pressors with Iarge air-flow capacities and high pres-sure ratios and efficiencies. Compressor research, there-fore, is being directed toward solving aerodynamicproblems of compressing air ticiently in a compressorof minimum frontxd area, minimum len=@h,and mini-mum complexity, so that the unit will be mechanicdysturdy and easily manufactured. A rdiable enginehaving comparatively low initial cost can thus be ob-tained. Compressor research consists of theoreticalviork on compressor aerodynamics, ~~ide vane studies,cascade investigations, and single-stage and multista=~compressor investigations.

The theoretical approach to the aerodynamics of com-pressors has been concentrated on obtaining a workingknowledge of the flow phenomena aseeiated with thecompre~or and its operat~m conditions. As an ap-proach to the solution of the three-dimensional flowthrough compressors, a general through-flow theorycorresponding to axially symmetric flow has been de-veloped (Technical hrote2302). The theory is applica-ble to both direct and irwe~e problems and is derivedprimarily for use in machines having thin blades ofhigh SOfidi@.

In order to approximate t-he circumferential wria-tion of the flow conditions, which is neglected in thethrough-flow schtion, several different approaches havebeen used. Wlen the radial component of flow isnegligible, the flow follows along cylindrical surfacesand may be analyzed in terms of the equivalent two-dimensional cascade. The method developed for de-signing cascade blades (Technical Note 22$1) with pre-scribed velocity distribution for subsonic compressi-ble flow based on a linear pressure-volume relation has

--

22 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

been extendecl, rind expressions for estimating the tic-curacy of solutions have been developed.

For cases where the radial component of velocityis not negligible, a better approximfition to the actualflow is obtained by assumingthe flow ta take place alongthe surfaces of revolution, as obtained from the axiallysymmetric solution, and then determining the illowbetween the blades along these surfaces of revolution,Both the direct and inverse problem for subsonic flowhave been analyzed (Technical Note 9407).

A rapid but approximate blade-element-designmethod (Technical hTote2408) for compressible or in-compressible nonviscous flow in high-solidity statorsor rotors of axitil-, radia~-, or mixed-flow compressorshas been developed. The method is based on channel-type flow between blade elements on a specified surfaceof revolution that lies between the hub and shroud andis concentric with the axis of the compressor. Theblacleelementis designed for prescribed velocities alongthe blade-element profile.

The characteristic equations for the axially symmetricflow in supersonic impellers have been developed andused to investigate flows in several configurations inorder to ascertain the effect of variations of the bound-ary conditions on the internal flow and work input(Technical Note 2388).

A theoretical discussion of the application of bladeboundary-layer control to incrmse the efficiency and thestage pressure ratio and to improve off-design perform-ance of turbornachinesis given in Technical Note 2371,Also presented is a method based on potential flow of acompressible fluid for designing suction, or ejectionslotted, blades having a prescribed velocity distribu -tion along the blade and in the slot.

The boundary-layer profiles on the casing of an axial-flow comprwsor were measured behind the guide vanesand behind the rotor. Using these measurements andthree-dimensional boundary-layer momentum-integralequations which were developed (Technical Note 2310),a qualitative consideration of boundary-layer behavioron the walls of an axial-flow compressor was made.This consideration shows that the important parame-ters concerning the secondary flows in the boundarylayers are the turning of the flow and the product ofthe curvature of the streamline outside the boundarylayer by the boundary-layer thickness.

Turbine Research

the result of compromising the turbine aerodynamic-swith mechanical considerations to obtain reasonable

stresses. The turbine research is therefore being timedat improving the turbine perfornvmce. Turbine cool-ing is also commanding considerable attention as ameans of improving the compromise between the re-

quirements of str&.ss and aerodynamics. Turbine re-search consists of theoretical turbine aerodynamics inwhich the theories and tools developed for compressors

are readily applicable, caecade invest igation~ and

single-stage nnd multistage turbin~ resenrch.

In orcler to facilitate the determinatio~ of the bestdesi~w compromises in the design of turbines, a methodwas de-relopecl for the computtition nncl gruphical pres-

entation of a series of possible turbine desi~ls for nny

specific application. Design charts are ma& to aid in

the study .of the effects of turbine rndius ratio ancl di-ameter on important design parameters such us Machnumber, turning angle, and blade root stress, The

methocl for constructing these chnrts is presented inTechnical Note 2402.

Non-twisted-type rotor blades are desirable where

internal passages in the blades nre required fur t ur-

bine cooling. An analytical evaluaLion has been madeof the nero~ynamic characteristics of turbines with non-

tw-isted rotor blades by comparison with the correspond-ing characteristics of free-vortex turbines. The results

of this kvesti@ion, including working clmrts for aidin designing non-twisted-rotor-blncle turbines, are pre-

sented in Technical Note 2365.

Turbine Cooling

The research program for the application of coolingto gas turbines has two objectives. The first is the elim-ination of critical metals from the turbine rotor of gus-turbine engines so that alloy steels of higher strengthancl lower critical material content can be used w~lleextending the useful life of turbine blades. The secondobjective is to provide the means of operating gas tur-bines at higher gas temperatures to achieve the largepotential gains in thmst of the turbojet engin~ and theincrease in power and the lower specific fuel consump-tion inherent in the turbine-propeller engine. Pastanalyses and cascade investigations show that tho bhule-temperature reduction required to permit substitutionof noncritical metals can be achieved with accept~blecoolant flow.

Solutions for a system of ~eneralized equations forThe problems associated with the turbine component the lnrninarbounda~y layer vri-tiheat transf& have been

of the turbojet engine are similar to those of the com- deve~oped for the determination of 10CO1heat-transferpreswr when good performance is required for appli- coefficients. Numerical solutions have been obtainedcation to transonic and supersonic a.iroraft. The prob- for low Mach numbers over a wide range of coolant flow,lems in obtaining light, efficient, and dependable tur- temperatureratio, and pressuregradient with xllowancebine components f or driving compressors are in general for fluid property variations. Solutions to the equa-

REPORT NATIONfi ADVISORY COlOfIT’TEE FOR AJIROXAl?TKX 23

tiona for the high Ifach number range are no-w being ef-

fected through the use of automatic computing nm-

chines (Tectical A’ote 9407)..%ml.ytical methods for computing one-dimensional

spanwise or chordwiee temperature distributions in

liqui&cooled turbine blades or in eimpIifled shapes usedto approximate sections of liquid-cooled turbine bl&s

h:{ve been summarized (Technical Note 23S41).

B1ade Vibration and Flutter

An experimental spin rig was used to determine the

effect of root design on the damping of loosely mounted

blades. The conrentional ball-ttnd-dovetail roots -wereahown to have the same characteristics in that tighten-

ing occurred at relatively low values of centrifugalforce, thus elimintiti~~ the advantag= of the loose fit.

The fir-tree and the hinge designs, ho-wever, had differ-

ent characteristics, the fir-tree tightening at the rela-

ti~ely high centrHuggal loadings and the hinge root re-

maining loose throu@out the speed range investigated.Methods have been developed for computing the nat-

ural modes and frequencies of arbitrarily shapedtwisted cantilever beams. Use has been made of theconcept of station functions. b analysis is being madeby this method to compute the naturtd modes and fre-quencies of a group of different compressor and turbineblades. The computed values will be compared witheqerimentd ~alues in order to evaluate the analytica~method (Technical Note 9300).

ENGINE PERFOR71ANCE AND OPERATION

Performance and Operating Characteristics

The performance of turbojet, turbopropeller, andram-jet engges has been investigated over a ra~~e ofaltitudes and flight Mach numbers. In addition to ob-taining altitude performance characteristics, the ef-fects of Reynolde number, burner blow-out limits, alti-tude starting characteristics, and component perform-ance were studied. As a result of these investigations

basic design changes were recommended -which resultin improved power plant performance for future en-gines. Various principles of thrust augmentation have

been evaluated experimentally under a ~arie~ ofengine operating conditions.

& anal@ was made to obtain an expression for the

opt bum jet-pressure ratio for any turbine-propellerengine. The results of this analysis, reported in Tech-nical Note 9178: are presented in the form of chartsfrom which the jet-pressure ratio for the division ofpower giving maximum tluw.ssmaybe obtained for en-gines either with or without intercooling, rehea~ re-generation, or any combination of these modifications.

halytical e-mluations of tierent methods of powerextraction from an axial-flow-type turbojet en=ginehave

been completed. These results ha~e been presented interms of generalized parameters that facilitate their ap-plication to different engines. The data cover therangg of power extractions available from the engineson a range conside~ ample for all auxiliary-powerrequirements. The power-extraction methods are com- .—

presaor-outlet air bked, shaft-power extraction, tur-bine-inlet or tail-pipe hot-gas bked, and the use of attlil-pipe heat exchanger on a turbojet en=tie as anauxiliary power (or energy} source. The W threeparts of this investigation are reported in TechnicalNotes 2166, ZW2, and 2304.

Engine Controls

A variety of engine control loops hare been ewdu-ated experimentally to determine effects of interactionand stability on engine operation. Several theoreticalstudies viere conducted to determine optimum controlarrangements for wmious engine types.

An analysis was made of the effect of independentvariations in the component ticiency characteristics,flight conditions, and engine size on the time constantand the turbine-irdet-temperature overshoot of a turbo-jet engine mith a centrifugal compressor and a turbinewith choked stator. The dynamic factors viere ca~cu-lated from the thermodynamic equations of engine- . —component performance. This invest.igtition is re-ported in Technical Note 2182.

The general form of transfer functions for a turbo-jet engine with taiIpipe burning vias developed and therdations among the ~ariables in these functions wemfound from the transfer functions and from enginethermodynamics (TecbnicaI Sob 2183). By means ofthese relations, the dynamic characteristics of the en-~ginecan be found from steady-state data and one tran-sient relatiom

As reported in Technical Note 237S, a rational an-alytic method for the design of automatic control sys-tems was dereloped that starts from certain arlitrarycriterions on the transient behavior of the system andderives those physically realizable characteristics ofthe coMroIIers that satisfy the origina~ criterions.

Accurate lcnovdedge of the dynamic response char-acteristic of turbine-propeller engines and the factorsthat aflect these characteristics are of great importancein the design of quick-acting: stable controls for this typeengine. h in~estigation of the dynamics of a turbine-propeller engine was made at sea le~el (Technical Note21S4) and in the altitude wind tunnel employing thefrequency-response technique for a range of altitudes. ..

Directhg research &ort toward the improvementof the turbine-propeller engine requires an appreciationof the relative importance of the various engine-com-ponent characteristics. b analysis is b-o made to

24 REPORT~ATIOXALADVISORYCOM&fITTEEFOR AERONAUTICS

determine the influence of interdependent character-istics, such as component size, e%iciency,and flow capac-ity, on the performance of the turbine-propeller engine.Results me evaluated on an airplane-performanm basisso as to reveal the ultimate effects of the variables underinvestigation.

Thrust Augmentation

A theoretical analysis of thrust augmentation ofturbine-propeller engines is in progress. Methods ofaugmentation considered me tail-pipe burning, com-pressor-inlet water injection, and a combination ofwater-injection and tail-pipe burning. Augmentedperformance with tail-pipe burning has been deter-mined for high subsonic and for supersonic speeds.Calculations are in progress on the augmented perform-ance with water injection over a range of flight condi-tions from take-off to transonic fllght at altitud~ andon the performance at high speeds with a combinationof water injection and tail-pipe burning.

An annlysis is being conducted for the prediction ofthe jet flows, pumping characteristics, and jet thrustobtainable from conical ejectors in order to determinethe rules for the design of such ejectors for maximumeffectiveness. A one-dimensional analysis of conical-air-ejector performance was made using an assumedprewure gradient along the conical secondary shroud.

ENGINE MATERIALS RESEARCH

High Temperature Materials

As a part of the search for materials having physicalproperties suitable for use at higher and higher oper-ating temperature% considerable effort is being ex-pended in trying to improve the physical properties ofthe current materials. Factors which influence the hightemperature strength of alloys are melting practice,forging, or casting procedures, and the heat treatmentsselected. To gain a better understanding how heattreatment affects the structures of alloys and the result-ing physical properties, studiw have been conducted ofthe fundamental factors which control the propertiesof austenitic alloys having exceptionally high creep andrupture strengths in the temperature range of 1,200° F.and 1,500° F. Such a study has been completed onInconel X (Technical Note 2385). Correlations of themechanical properties with structural analyses weremade. It appeared from the study that aging resultedin some improvement in rupture strength in the rangefrom 100-1,000 hours rupture time at 1,200° F. Thisimprovement was obtained apparently through increas-ing the resistance to creep prior to fracture. This isin contrast to results obtained with N-155 wherein theimprovement appeared to be through the formation ofa grain boundary phase.

As a part of the study of the conservation of strategicmaterials for aircraft engines, efforts are being &l-rected toward the evaluation of substitute mtiterialsof

-..

reduced alloy content. Among the materials studied -for sheet applications is AISI 31OB (Technicnl Note2162). One of the draw-backs of thk material has beenlow ductility in the temperature range from 1,200° F. ““to 1,400° F. The objective of this research was to de-termine whether service at 1,700° F. to 1,800° F. wouldcause increased brittleness at 1#00° F. to 1,400° F.with resultant cracking during hertting and cooling.Stress rupture testswere made in the 1,900° F. to 1,400°F. range with a few tests at 1,700° F. and 1,800° F.Among the variables considered were heat-to-heat re- —producibility, the relative effects of nnneding, m-idhotand cold working as initial treatments. It was foundthat the elongation at 1,300° F. was increased by priorheating from 1,700° F. to 2,000° F. In addition, itwas determined that the cold-rolled stock hwl thelowest ductility.

Inmmuch as several of the important high-tempera-.—

ture alloys utilize-both chromium and cobalt and be-cause a number of the physical properties of an alloyare controlled by diffusion processeswithin the alloy inthe solid state, an investigation was conducted to deter-mine the diffusion coefficients of chromium in thealpha cobalt-chromium solid solutions (Technical Note2218). The method employed consisted of pressure-welding cobalt and cobalt-chromium bars, annealingthese joined bars at constunt temperatures and deter-mining the distribution of chromium through the diffu-sion zones thus formed. It was found thnt the diffusioncoefficientsat 1,000° C., 1,150° C., 1,300° C., and 1,360°C. were relatively constant. It was further found ihtitchromium difiusivity from alpha cobalt-chromium al-loys into cobalt is greater than chromium diffusivityfrom liigh-chromiurn alpha alloys to low-chromiumalpha alloys for all concentration gradients studied.

Studies of the properties of molybdenum at high tem-peratures have been continued. The effects of s-waging,recrystallization, and ‘test-section” area on the strengthproperties of sintered wrought molybdenum were deter-mined at temperatures from 1,800° F. to 2,400° F.(Technical Note 2319). The amount of svvagingon thespecific bar sizes investigated had little effect on thetensile”strengths, but increasing amounts of swagingprogressively lowered the reorystdlization tempera-ture. Increasing the test-section area of a specimenhada negligible effect on the tensile strength. Wroughtmolybdenum had a 100-hour stress-rupture life of ap-proximately 19,300fi300 p.s. i. at 1,800° F.

Studies of ceramic coatings for the protection ofceramals and le~ strategic alloys from high ten~pera-ture oxidation and corrosion have led to the develop-

RIWORT NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS 25

ment of a ceramic coating with a high chromium metaIcontent. Evacuations of these coatings on a TiC baseceranml htive demonstrated the ability of the coatingto protect against oxidation as viell as its ability tovrithstwd small elongations and severe thermal shock(Technical Notes %3S29and 2386). It -wasfound that iugeneral the best protection was obtained in oxidationtests at.the higher temperatures. Studies of the effectsof firing time, firing temperature, ancl the number ofcoatings applied indicated thrd there is an optimum&ing time anclfiring temperature. For the coathqg stud-ied? t-woapplications pro~ed superior to one.

Studies of the effectiveness of ceramic coatings inpreventing high temperature corrosion by lead-bromidevapors indicate that the ceramic coatings appeared to beinert to the PbBrZ and successfully inhibited corro-sion of the alloys studied for a 6-hour testperiod (Tech-nical h~ote2380). The alloys S416, HS–21, Inconel,l!MID~ and .AIS1 347 ‘were tested (a) in an uncoatedcondition, (b) in a precm.idizedcondit.ion~and (c) in acoated condition when exposed to the lead-bromidefumes in an air atmosphere at ~350° F., 1,500° F., and1,650° F.

As a part of the general program for the ewdua-tion of cerwnaLs, investigations ha~e been completedof the bonding of TiC with Al, Be: Cb, Au, Fe, Pb, Mg?Mn, Pt, Ti, and Va (Technical Note S?18~). The testprocedure consisted of placing powdered metal in a cup-shapecldepression formed in a hot-pm- TiC testbar,inserting the specimen in a furnace at temperatures upto 3,650° F. Studies -weremad~ of the sectioned speci-mens to determine what kind of bonding, if any, tookplace. Of the eIements studied+ only nickel, cobalt,chromium? and silicon bonded ~th titanium carbide.There was some indication of a limited solubiIity oftitanium carbide in nickel and cobalt.

A continuation of the study outlined above tvas con-ducted, utilizing zirconium carbide and cohunbium todetermine the bonding mechaniem (Technical Note2198). The results. indicated that the mechanism isone in which cohunbinm atoms diffuse into the zirco-nium-carbide lattic~ displace zirconium ato~ andform zirconium metal and a completely soluble colum-bium carbide. This results in a homogeneoussolid solu-tion of the zirconium-carbide matrix and the columbiumcarbide. The size and the distribution of the metalphase -wascontrolkd by sintering time and temperature.In general, the specimen with a fine dispersion of metalhad the highest strength.

Stresses Research

The failure of turbine and compressor blades due tovibrations has led to an increased interest in the de-

2130K—5~

termination of the naturaI modes and frequencies. &-suming a compressor or turbine blade acts as a canti-lever beam, a method has been deveIoped for calculat-ing the coupled modes (Report 1005). The methodis based on the concept of Station Functions and per-mits the calculation of the modee and the frequenciesof nonuniform cantilever beams vibrating in tmsion$ -bending, and coupled bending-torsion motion. Resultsof the application of this method show that the effectof coupling betvigm bending and torsion is to reducethe first najmral frequency to a value below that whichit -wouldha~e if there were no coupling.

In the design of a turbine rotor it is desirable tobow the detailed stnxs and strain distributions in thestrain-hardening range and the amount of increase inload that can be sustained betvieen the onset of yieldingand failure. A simple method of solving the plane-stress problems with axial symmetry, employing thefinite strain concept in the strain-hardening range, andbased on the deformation theory of Hencky and Nadai,has been derived for the condition that the directionsand ratios of the principal stressesremain constant dur-ing loading (Technical h’ote 2217). The results indi-cated that the ratios of the principal stniss- remainessentially constant during loading and, therefore, thedeformation theory is applicable to this type of prob-lem. In general, it may be said that the deformationthat can be accepted by the member before failure de-pends primarily on the masimum octahedral shearstrain of the material.

In the design of high-stressed machine parts, a kno-ivl-edge of the stressand strain concentration due to a holeand also of the distributions of stressw and strains in thestrain-hardening range is desirable. & a continuationof the -work reported above, a linearized solution hasbeen obtained for the problem of plastic deformation ofn thin plate -witha cirmdar hole in the strain-hardeningrange (Technical hrote2301). This solution is based onthe deformation theory of plasticity for finite strains.The rewdts indicate that the data obtained by the line-arized method compare closely with those obtainedwithout linearization. In addition, it was found thatthe solution for an ideallj plastic material with the in-finitesimal strain concept gives good approximatedues of tiains but not of stresses.

A further study of the distribution of stresses andstrains in the strain-hardening range has led to a partlylinearized solution of the plastic deformation of a rotat-ing disk considering finite strains (Technical Note236’7). The results indicate that the variation of a pa-rameter, which is determined from the octahedral shearstrees-strain curve of the material, can be l~ed as a gen-

—

26 REPORTNATIONALADVISORYCO1l.hlITTEEFOR AEROXAWTICS

era] criterion of the applicability of the deformationtheory. In addition, it appeared that the rotatingspeed of a disk for a given maximum strain of the diskcan be determined directly from the true tensile stress-strain curve of the material.

A continuation of the investigation reportecl in Re-port 1005 has been completed to determine the effect oftwist on vibrations of cantilever beams (Technical Note2300). It is shown that for a beam with a ratio ofbending stiffnws in the two principal directions equalto 144, the effect of coupling due to twisting is to raisethe value of the first natural frequency by a very smallamount, to decrease steadily the second frequency, andto lower the third frequency considerably.

A significant question to be considered in the specfi-cation of chemical composition and mechanical andthermal treatment of a rotor cliskis the compromise be-tween ductility and tensile strength. An investigationwas conducted to detertine the strength-reducing ef-fects of several types of “irregularities, various ductili-ties, anclan optimum compromise bet-mm ductility andthe tensile strength in the presence of such defects(Technical Note 2397}. The strength of disks contain-ing irregularities increased with increasing tensilestrength independently of ductility at ductilities in ex-cess of 14.9 percent elongation. The best compromiselwtween ductility and tensile strength in rnateria~con-taining shrink porosity occurred at &8 percent elong-ation.

The application of X-ray diffraction techniques toa study of stress analysis indicates that the back reflec-tion techniques will yield a reasonable strain am”imacyunder favorable conditions Because the conventionalexperimental methods reduce the precision in determin-ing interatomic spacing and restrict the analysis tothosa materials which yield a reasonably sharp diffrac-tion pattern, a new technique and camera have been de-vised (Technical Note 2224). A calibration of thecamera, using a gold powder standard having a reportedatomic spacing of O.91OO8A,yielded an accuracy of

atomic spacing of approximately A 4 x 10-5A. A com-parison of the new technique with the results obtainedfrom the conventional equipment and techniques indi-cated that a more precise and dettiiledanalysis of atomicstrain could be obtained.

ROCKET RESEARCH

The major problems of rocket research are to se~ectfuel and oxidant combinations that give large thrustper unit weight flow and volume flow and still haveproperties that permit their handling and us% toprevent failure of the engine from high temperaturesattained, to achieve efficient combustion in the sn-dlestpoesible unit, and to evaluats the optimum applicationof rocket propulsion.

Rocket Propellants

Investigations of rocket-propellant performwwe areusually.preceded by theoretical analy= of thtiperform-ance of various fuel-oxidant combinations. Theseanalyses are used as a basis for selecting the propellantsworthy of experimental Evaluation. Conlpilation ofthe thermodynamic functions to be used in these analy-ses has been continued.

An analysis was made to show the relative importanceof specific impulse and propellant density on missileper-formance. The analysis compares propellant combina-tions having different specific impulses and densities bydetermining the leastgross weight of a missile to accom-plish a given mission.

Rocket Combustion

A basic study of the hydraulic characteristics of in-jection systemswas started as an aid in estubfishing therelation between injector method and combustion chm-acteristim. Initial studies of two impinging jets ofwater revealed that the spray disintegrates into groupsof drops which for the conditions existing in a rocketcorrespond to frequencies observed in combustion fluc-tuations, These results are reported in Technical Note2349.

AIRCXAI?T CONSTRUCTION

The NACA is continuing its efforts to enlarge thescope and the amount of its research on airframe con-struction problems. The need for such an increase ineffort has been previously pointid out and the mannerin which it ie to be accomp~ishedis under study.- Programs during the past year have included exten-sive laboratory and flight research and the continuedcollection of statistical data on gust loads encounteredin regular airline operation. All airframe constructionproblems have been complicated by the increasing alti-tude and speeds of flight and these two factors can be

.,

found at the root of most new structural design prob-lems.

As in the past, a considerable amount of the NACArssearch on structural materials and structureswas per-formed under contract at universities and other non-profit scientific organizations.

In accordance with the policy of hohling technicalconferences with representatives of the rrilitary serv-ices and the aircraft industry, a conference on aircraftloads ancl structures wtis he]cl at the Limgley Labora-tory in the spring of 1951.

REPORT NATIOX’AL ADVISORY C03~ FOR AERONAUIMCS 27

A cleecription of the Committee-s recent unckissitied type are more nearly plates than beams and can beresearch on airframe construction is given in the follo-w- andyzed by plate theory. However, solutions to theing pages and is divided in four sections: Aircraft partial-differential equations of plate theory are notloads, structures, vibration and flutter, and aircraft readily obtain@ especially for plates of arbitrary shapest.ructuralmaterials. and loading. A method is presented in Technical Note

AIRCR4FI’ STRUCI’UR.ES 2.369for obtair@ ordinary differential equations to re-place the partial-differential equations. This simpli-

Stress Distribution fied plate theory has been applied to spedc problemsinvol~o static cleflectionj v~bration, &d bu&ing ofExperimental inw.stigations have shown that the Cantderer ~lates

stresses and distortions arising at the ming-fusdage .

juncture of swept viings are appreciably dif-erent from One proposed method for increasing the storage space

those occurring in straight wings. Some theoretical inside a wing is to replace the ribs tith u number of

work sho-wh+gthe E&ectsof s-weep-back on the defkc- vertical posts connecting the compression and tegsion

tion of box beams under bending and torsion loadings co-remof the wing box beam. A theoretical study of an –

had been published, but there was a need for an amdysis ideaIized post-box configuration had indicated that the

givirg the stresses at the triangular root section of a compression cover of a box beam couId be stabilized by

swept box beam. Accordingly, a method presented in posts with an attendant weight saving. In order to .1.

Twhnictd 2iiote2232 was developed for anal@ng the check the validity of the theory developed, a beam was

triangdar portion of the box beam and for &abli&ing tested and the results reported in Technical Note 2414.The experimental buckling load vrasin good agreement .. .continuity bet-men this section and the carry-through

.wtio~ as well as the outboard portions of the box vvitb theory, but appreciable distortion of the beam

beam. The results obtained by this method were coru- cross section occurred before the buckling load was

pared -withpre-riousIy published test data. The agree- reached. It me concluded that a propsr combination

ment was found to be fair, with the principal discrep- of posts and ribs may make a design that wouId be —

ancy beii due to the fact that the method is breed on satisfactory with regard to both deformation and

a -rerysimple type of idedized structure which prevents strenggh.

the appearance of shear lag in the results. An exten- The skin on the upper surface of a wing is subjected

sion of the basic approach was therefore made in order to compression by the bending of the wing, and in most

that it might include the effects of shear lag. cases the addition of stiffening elements to the skin is

I&act solutions for the stresses and deformations in required to enable the compression load to be carried.

wings subjected to torsion we not easily obtaimed. Ore- Direct-reading design charts have been prepared for

gon State College has therefore developed an approxi- 75S-T6 ahminum aUoy flat compression panels having

mate method of solving for the angle of twist, longi- lorygitudinal extruded Z-section stiffeners. ~=etudinal stresses, and shear stresses in torsion boxes of

.-charts, which are presented in Technical Ifote 2-EM,

rectangular? eIliptical and airfoil cross seotions. The co-rer a tide range of propositions and make possiblethe &rect determination of panel dimensions requiredresults of these theoretical studies indicate trends for ._.

consideration in design. to carirya given intensity of loading with a giwn skinFor proper design of cut-outs that occur in st.ifiened- tfic~ws ~d eff~tive length of panel. They aIso make

shell structures, a detailed knovded=% of the redistri- possible the determination of the panel proportions hav-bution of streesesaround the cut-outs is necessary. h ing minimum weight and meeting the desi=~ conditions.approximate theory had been developed for the analysis A type of sandwich plate widely used in airplane con-of stresses in torsion boxes containing large cut-outs struction consists of a corrugated metal sheet rhetedwhich is adequate for the design of au ~mponent~ of betmeentwo metal face sheets. In order to apply exist-such structures except the cut=out cover. w ‘eo~ ~~ sandwich-plate theories to the analysis of the corru-vias extended in Technical Note 2290 to permit a moredetailed calculation of the stresses in the cover. Nu-

gated-core sandwich plate, a Imovdedge of certain ekstic

merical resuh were compared with experimental data constants which describe the distortions of the sandwich

and also with the resuIts of a sohkion made by a more plate under simple loadings is required. Formulas for ._

elaborate numerical procedure. The agreement was evaluating these elastic conssants for the corrugatad-

found to be satisfactory m all cases except those tith core type of sandwich have therefore been deri-ied and

very large cut-outs and flexible bulkheaik pressnted in Technical Note 2289. Suggestions haveFor analysis of thin solid wings of smalI aspect ratio, also been made as to the method of extending existing

such as might be used in supersonic airplanes and mis- sandwich-plate theory to make it strictly applicable tosil~ beam theory is no longer adequate. Wings of this the unsymmetrical type of corrugated-core sandwich.

28 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAU’HCS

Pressurized cabins of high-altitude airpkmes presentmany stress analysis problems unusual to the aircraftfield. Tlmw problems have been reviewed by StanfordUniversity and a report containing a summary of theavailable iuf ormation on these problems has beenprepared.

The ultimate load-carrying capacity of stiffened-shell structures which are subjected to combined loadsis a subjed on which little information is available, Inorder to investigate one phase of this problem, a sefiesof five large stiffened circular cylinders was tested tofailure under various combinations of torsion and com-prasion. An interaction curve for the strength ofstringers that fail by local crippling was determined,and data were obtained on stringer stressesfor stiffenedcylinders under combined loads. The test results anda method for estimating stiffener stressesare presentedin Technical Note 2188.

Stability

In 194’7 Shanley showed that it was possible for astraight column in the plastic stress range to start tobend at a load given by the Euler formula with thetangent modulus of elasticity substituted for Young’smodulus of elasticity. He also pointed out the exist-ence of a maximum column load which was greater thanthe tangent-modulus load. In order to determine theamount by which the maximum load could exceed thetangent-modulus buckling load, a study of column be-havior in the phstic stres range was undertaken, theresults of which are reported in Technical hTote2267.This study confirmed the existence of the tangent-modu-lus buckling load, and showed by a rigorous load-de-flection analysis the relation of the maximum load tothe stress-straincurve of the material.

A t.hin-wded fuse~age may buckle either by defor-mation of the entire column (column buckling) or bydeflection of its component webs and flanges (local buck-ling). Methods are available for the determinationof the buckling load for each mode of failure, and itis common practice to aemunethat a column will failat the lower of the two loads in a mode correspondingto this load. In reality, however, there is an interac-tion of these two modes of buckling so that the actualbuckling load is smaller than that which is ordinarilyused. An investigation has therefore been conductedby Cornell University for the purpose of determiningthe interaction effect between column and local buck-ling. The results of this study indicate that this effectis negligible for box sections and for common sizes of I,H, and channel sect.iousbut may be sig-nificmt for sec-tions possessing torsional, instability, such as T andangle shapes.

A method has been developed by the National Bureauof Standiirds for computing the compressive load for~ateral elastic instability of hat-section stringe~%andis presented in Technical Note 2272. Applying themethod to a range of shapes and lengths of hat-sectionstringers shows that such stringers are unlikely to failby lateral instability.

The use of swept wings and tail plan forms with ribsplaced parallel to the flight path results in sheet panelsthat am-parallelogram-shaped. Few data exist on thestability of such panels under the loadings that arisedue to wing and tail bending. Accordingly, in Tech-nical Note 2392 charta have been prepared givingtheoretical compresive-buckling-stress coefficients forcontinuous flat sheet divided by nondeflecting supportsinto paridlelogram-shaped punels. Over a wide rangeof panel aspect ratio, such panels are decidedly morestable than equivalent rectangular panels of the samearea. -

‘l%ernd Effects

The determination of the structural effects of nonuni-form temperature distributions, such as might be pro-duced by aerodynamic heating, is rapidIy becoming aproblem of interest to aircraft designers because non-uniform temperature distributions have important andcomplex effects on the stresses and distortions of thestructure. The calculation of the stresses due to non-uniform temperature distributions has been treated byseveral investigators, since the problem has long beenof concern to po-iver-plant designers; however, methods

that would be directly applicable to the thermoplasticanalysis of aircraft structures are not yet available.Two preliminary studies have therefore been completed

on this subject. The first, reported in Technical Note224o, considers the two effects of temperature changeson aircraft structures: The introduction of thermal

stresses and distortions as a result of restrained thermalexpansion, and the change in behavior of the structureresulting from the variation of elastic properties of

matarials with temperature. These effects have been

illustrated by sample analyses of the stress and distcm-tion distributions of simple box beams and by calcula-

tion of the stresses in a typical wing section, The ana-lytical methods of. the first study provide a relatively

simple means of approximating the eflects of tempera-

ture changes; however, they often yield inaccurate val-ues for the secondary stresses in complicated structures,and in such cases some numerical approach is desirable.

The second study, reported in Technical IVote 2241, ex-tends a previously published numerical method of stress

awlysis to include tie eflect.s of a nonuniform distribu-tion of temperature. An illustrative analysis using thismethod was made of a two-cell box beam under the

REPORT N-ATIONAL ADKLSORY

combined action of vertical loads and a nonuniformtemperature distribution.

Syracuse University has conducted an experimentalinvestigation of the temperature and stress gradientsresulting from the application of heat to the skin of anumber of skin and spar cap combinations. The 75S-T6 ahuninum alIoy specimens with a range of skinthiclmesses were heated at various ratw ta provide abetter understanding of heat flow through high-speedaircmft wings.

Fatigue

An investigation is being conducted on the fatiegestren=ti of full-smde airplane structures. The re-.mlts, to date, indicate a surprisingly small amount ofspread in the fatigue life e-ren though dl the fatiguecracks do not origgte at the same point. IiMectivestress-concentration factors hare been computed andcompared -with results from tests of small laboratoryspecimens. The importance of fatigue crack Iength on

crack growth is pointed out in these tests. In con-

nection -with this work the structural damping of atypical airphme w@ has been determinecl. Thesemeasurementswere carried out by the shock-excitationmetho~ with the resultant frequency of vibration beingthat of the wing fundamental bendi~mfrequency. Theresults are in a~eement with those of other experi-menters -who have measured structuml damping ofsmaller wing specimens. They indicate that the damp-ing increases with amplitude of vibration.

AIRCRAFI’ LOADS

Steady Flight Loads

A simplitled Iifting-surface theory has been appliedto the problem of evaluating span loading due to flapdeflection for arbitrary wing planforms (Technical Note997s) . A procedure was de-reloped from which theeffects of flap deflect-ionon span loading and associatedaerodp-unit c.haracteriaticscan easily be computed forany -wingthat is symmetrical about.the root chord andthat has a straight quarter-chord line Gver the w@geemispan. The effects of compressibility and spanwisevariation of section lift-curve slope are taken into ac-count b? the procedure. The load distribution and Iift

due to flap deflection were prepared in chart form for abroad range of wing planforms for the case of straight

tapered wings and a comparison between experimental

values of flap effectiveness and ~alues obtained from

these charts show good agreement between theory and

experiment

CO~TEE FOR AERONAUTICS 29

Maneuvering Loads

k airplanes increase in size and vieight, experi-mental data must be obtained to evaluate currentmaneuvering taiI-load design requirements and to t&stin extrapolation to the huger airplanes. The need fordata arises from the variations in the response of the “.airplane as size increases, and also because a pilot’smentaI attitude and his control actions will vary ac-cording to the size and type of airplane. In view ofthe gaps in existing data a joint project for fight test-ing the Lockheed Constitution (design gros vieight184,000 pounds) was conducted by the Navy Depart-ment: Bureau of Aeronautics: and the N.-CA.

These tests, reported in Technical Note 2490, indi-cated that the analytieal process of estimating themaneuvering tail loads for a large airplane need belittle different from that for small airplanes. TheffexiiiIity of the tail had a minor effect on the estimatedtail load and the resulting response of the airplane.Because of the relatiYely SIO-Wresponse of the airplane,the piIot was forced to anticipate the airplane rqonsein applying control forces; for this reason the pilotsoften unknowingly obtained undesirably high load f ac-

tors. The piIots -were unaware of the critical tail loadsarie@ from abrupt. restoration of the control to neu-tral during a pti-up or sideslip. PiIota aIso expreesedthe opinion that.the roLIingpull-out maneuver felt aim- __ilar to maneuvers required to reco-rer from disturb-ances to flight in rough air.

Gust Loads

The dynamic behavior of an airplane -wing duringflight through rough air was in~estigated by fight tests

on a twin-engine transport airplane. ResuIts from

flights made in clear-air t.urbuIence were compared

with results from slow pull-ups made in smooth airused as a “quasi-static reference condition (~echnical

Note 2424).

&an extension of previous investigations of the ef-

fect of sweep on gust loads, t&s -were made in the

Langley gust tunneI on a 60° swept-back-wing modelto determine the effect of a large angle of sweep ongust loads. The results indicate that a simp~ed

method of snal-@s, using a slope of the Iift c_~e de-

rived by the cosine law and strip theory to estimate the

penetration effect is applicable to the prediction of gussloa& on wings swept as much as 60°. These reeulta as

welI as a summary curve representing the reerdts of –—

investigations with wing models having from 45°

sweep-f orward to 60° sweep-back are presented in Tech-nicaI NTote 9204.

30 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

An instrumentto indicate atmospheric turbulence hasbeen constructed and subjected to laboratol~ rmd flighttests. The design of the instrument was bused on pre-vious hlings that the rapid fluctuations of the airspeed in ~mstyair constituted a measure of atmosphericturbulence. The instrmnent consists essentially of avented air-speed diaphragm in a sealedcase with the Iagcharacteristics of the vent chosen so that the diaphra=gnresponds to the rapid changes in dynamic pressure ingusty air but remains insensitive to gradual changes re-sulting from normal air-speed changes. The results offlight and ]aborrdory tests indicate that the principleof design was a practicable one, but further design re-finementwould be necessary if the instrumentwere to baused in routine airplane operations.

The effect of atmospheric turbulence on the loads en-countered by aircraft in operational flight has beenstudied for sometime by analyzing records secured withthe NACA V–G (airspeed-acceleration ) recorder. Theinstrument originally employed was troublesome to ad-just and was limited in frequency response. An im-proved recorder has been developed which employs aviscous-damped accelerometer. Improved frequencyresponseof the accelerometer has resulted and the nece+s-sit,y for adjusting damping in the fielclhas been elimi-nated. The motion of the air-speed element has beenmade approximately linear with air speed; in addition,the element has been temperature-compensatecl. Thenew NACA oil-damped V-G recorder and its perform-ance characteristics are described in Technical lSote2194, and the results of tests which demonstrate im-provements to the older desi=g tirepresented.

The NACA VGH recorder descrih”d in TechnicalNote 2265 is a flight instrument designed to collect gust-loads data on transport aircraft with the accuracy re-quirecl for research purposes. Air speed, normal ac-celeration, and akitude are recorded on photographicpaper as a function of time and in the usual applications100 hours of continuous recording time is poesible. Asmall acceleration-sensing unit used with the recordercan be mounted independently of the recorder. Al-though built principally for collecting statistical dataon gusts encountered in scheduled airline operations, theinstrument records data in a manner which permitsmany studies pertaining to airplane operations whichhave air speed, normal acceleration, and altitude asparameters.

Landing Loads

With the advent of thin winga for high-speed flight,the increased use of external stores, and the trend to-ward airplanes of larger size, a lmowledge of the be-havior of flexible wings during landing becomes in-creasingly important. An investigation of a model

consisting of a hull in combination with a flexible wingwas made in the Langley impact basin, rmdthe data arereported in Technical Note 2343. These data.substan-tiated a theoretical method for considering the effect ofstructural flexibility. on the applied hydrodynamicforce.

The development of retr@able lifting surfaces forimparting favorable hydrodynamic behal’ior to stream-lined hulls has shown a trend toward the use of com-paratively flat surfaces which blend with the bottomof a fuselage. Data on the impact loacls and energyabsorption of heavily loaded flat surfaces when landedat various trims and flight-path angles are reported inTechnical Note 2330,

The validity of the reduced-mass method of repre-senting wing-lift effects in free-fall drop tests of land-ing gears has been investigated and the results are re-po~ed in Technical Note 2400. The behavior of a en-dhnding gear in the reduced-mass drop tests was com-pared with results obtained in a drop test where winglift forces simulating airborne impact were mechani-cally applied to the test specimen during impact, andwith results obtained in free-fall drop tests with fullweight. Values of landing-gear load factor and ratioof shock-strut ener~gyto impact energy obtained fromreduced-mass drop tests were in fairly goocl agreementwith the results obtained from simulated airborne in~-pacts. The values of impact period and shock-struteffectiveness were generally lower in the reduced-massdrop teststhan in the sirmdatedairborne impacts, whilestrut stroke and mass travel were generally greutcr inthe reduced-maw drop tests than in the simulated air-borne impacts. The free-fall drop testswith full weightproduced exce&ve values of load factor, impact period,strut stroke, mass travel, and impact energy, but valuesof strut effectiveness were in fairly good agreementwith those obtained in the simulated airborne impacts.

VIBRATION AND FLUTI’ER

Increased effort is being expended upon flutter studiesfor transonic and supersonic speeds. Unusual configu-rations are also being investigated in order to keeppace with desia~ trends for these speeds.

Unsteady Lift Theories

Calculations have been made of the forces on aero-dynamic bodies in unsteady motion based upon theclaasical equations governing acoustic clisturl.mnces.These calculations have been greatly expedited by up-plying t~chniques which were developed in recent in-vestigations of steady atate supersonic theory. The “-build-up of lift and pitching moments on slender, tri-angular wings and -wing sections undergoing sinking

REPORT NATIONAIJ ADV150EY

and pitchirig motions were calculated for subsonic,.mnic: and supersonic speeds. These results have beenreported in Technical Notes 2256, 2387, and 2403.These transient responses protide the necessary in-formation for the prediction of responses to osdatorymotions of arbitrary frequency and are therefore appli-ctible to problems in airplane dynamics and flutter cal-cnlatious.

Iterative Solution of FIutter

Existing methods of flutter analysis include the rep-resenttitive-section methocl, generalized coordinatemethods? matrix methods? and operational methods.V7ielandt has suggested an iterative transformationprocedure which is well suited to the flutter problemand sindar characteristic--ralue problems. Becauseboth the original and the translated work of Wielandtare difficult to follow? an explanation of the iterative-transformation procedure is giwm in Technical Note2346 and the application of the procedure to ordinarynatural vibration problems and to flexure-torsion flutterproblems is shown in numerical examples. It. appearsfrom this -workthat the method is of practical usef&ness. Comparisons of computed resdts with experi-mental results ancl with results obtained vrith othermethods of analysis hare akw been nmde.

Effect of Coupling Betw-een Modes

In an analysis of flutter invoking coupled vibrations,questions arise concerning the accuracy of us~c un-coupled modes or coupled mode% as the latter greatlycomplicate the analysis. &I amdysis of the Raleightype basecl on coupled mochd functions, was made fora wing with simulated engines, or tip tanks, represent-ing a wing -with high mass coupling. The wing con-sidered was uniform: unwept, ancl high a.speotratio,and was mounted as a cantile~er. The resdts of thisanalysis mere compared viith those of cmanalysis basedon uncoupled modes as -weI1as with experimental re-sults. For the configurations studied, aameement.withexperimental data -was obtained for both methods .j?fanalysis; therefore, the more complicatcxT&ouphii-rq@@anal-ysismaybe unnece=ary (Technical h“ote 2375f7”

Single Degree of Freedom FIutter

Beside the usual types of flutter in-rol~ing coupledmodes, the theoretical existence of a single-degree-of-freedom flutter has been indicated and is of interest indynamic stability. Therefore it -wasdeemed advisableto study the effects of some parameters aflecting thissingle-degree-of-freedom oscilhttiom One such analyti-cal study concerned the tiect of Mach number andstructural damping on single-degree-of-freedom pitch-ing oscillations of a wing. Some experimental results

“--–--–– COMIW.TTEE FOR AERONAUTICS 31

-were compared with theory and good agreement was

found for certain ranges of an inertia parameter (Tech-

nical Note 2396).

Sound

PropelIer noise has been a problem even at subsonictip speeds; hence the proposed use of propellers operat-ing at supersonic tip speeds has caused some concernbecause of the em-erity of the associated noise problem.Very little information is available which would allowa prediction of noise leveIs. Therefore sound measure-ments have been made for a two-blade propeIIer -withatip Mach number of 1.30. Sound spectrums mere ob-tained at both subsonic and supersonic tip speeds, andthe measurecldata were compared with calculations bythe Gutin thecq.

AIRCRAFT’ STRUCX’UIL4L 31ATERL4LS

Fatigue of Metsls

The project on fati=~e cd BattelIe 31emoriaIInstitutementioned in previous annual reports has continued,and significant prog= has been made in fuldIIing thepurpose of the program, which is to provide informa-tion src6icient1ycomprehensive to permit its applicationto design and to the estimation of fatigue damage. Thematerials being ir.mestigatecl in this program are24&T3 and 75S-T6 ahuninum alloys and EL&E4130steel. I&ults previously reported on ccnnotchedspeci-mens are contained in Technical Note 2394. Fatiguedata on notched specimens over a range of stress con-centration factors of 1.5 to 5.o are the subject of severalother reports. Those on stress concentration factors of~J) ~d .Q me ~ T~~cal ~~ote2399, and &ose onstressconcentration factors of 5.0 are given in TechnicalNote 9390. Data have ahcobeen obtained on specimenshaving a stress concentration factor of 1.5. This rangeof stressconcentrations is considered to be that of mostimportance in aircraft from the fatigue ~ievrpoint.

In the investigation of the statistical nature of fa-tigue at Carnegie Institute of Technolo.gy during thep~~ear, the statistics of the fatigue fracture curvesand endurance Iimits were determined for S&El 1050steel, annealed .bmco iron, and SAE 4340 steel in thequenched and tempered and quenched and spheroidizedconditions. The effects of metallurgical factors such ascomposition: heat treatment, and cleanliness on fatiguebeharior were shown by a statistical ardysis of theexperimental results. From this work it has been con-cluded that inclusions play the dominant role in thefatigge behavior of these materials. In addition, someother aspects of the fati=me problem -were studied,among which -werethe dependence of statistical varia-tions in fatigue life on strws level in the fracture range,

--

.-

-.

.“

—

32 REPORT NATIONAL ADVISORY CO-~EE FOR AERONAUTICS . ..-.

the statistic of the location of crack initiation, size

eflect, ancl understressing effects.Axial fatigue &ta were conducted at the National

Burenu of Sttinclarcls on flat sheet specimens of bare ancl

alclad 24S-T3 aluminum alloy to detertine the effect

of frequency of loading ou the fatigue strengths of thesematerials. The results of this inveetigation are con-

tained in Technical Note 2231 and show that the fatiguestrengths of the materials were slightly lees when tested

at 12 cycles per minute than when tested at 1,000 cycles

per minute.Another aspect of the fatigue problem was investi-

gated at the Pennsylvania State College. The purpose

of this project was to determine the influence of biaxial

tensile stresseson the fatigue strength of 14S–T4 alumi-num alloy when subjected to various ratios of biaxialstresses. Thess biaxial fatigue stremes were producedby applying simultaneously a pulsating internal pres-sure and fluctuating axial tensile load to a thin-walledtubular specimen. Fatigue etrengt.hs and S-N dia-grams were obtained up to about 10,000,000 cycles forfour principal stress ratios. The test results do notagree -withany particular theory of failure but are suf-ficiently close to the maximum stress theory to permitits use in design.

Plasticity

In the 1950 annual report reference was made to aninvestigation at the Pennaylvania State College on theplastic biaxial strea+strain relations. The results ofbiaxial tensile stress tests on 75S-T6 material are pub-lished in Technical Not.a2425, and the results of similartests on 14S-T4 aluminum alloy were obtained duringthe past year. The main purpose of this investigationwas to determine the validity of the plasticity theotieeand the correctness of the various assumptions made inthese theories. To accomplish this purpose and to sup-plement the biaxial tensile test results the investigationwas extended to include tests in which specimens weresubjetted to biaxial tension and compression. In thesetestsboth constant and variable streesratios were used.Although the data obtained do not agree with any ofthe current plasticity theories, it was found that thebiaxial yield strength conforms most closely with thedistortion energy theory.

For mathematical simplicity most plasticity theoriesassume solids to be isotropic and plastically incom-pressible. These assumptions& the value of Poisson’sratio in the plastic range at 0.5. Physical considera-tions, however, make it apparent that the transitionfrom the elaetic to the plastic value of Poisson’s ratio isgradual. An inveetigatiou of the variation in Poisson’sratio in the yield region of the stress-strain curve wascompleted by New York University duri~o the past

year, It is in this region that the transition f mm theelastic to the plastic value is most pronounced. Thistransition was studied experimentally by a systematicsystem of tests on 14S–T6, 24S-T4? ancl75S-T6 alunli-mun alloys under simple tensileand compressive stressesalong three orthogonal axes. The data obtained onPoisson’e ratio in the yield region aswell as values of theplastic dilatation for stmin deviations up to 0.Gpercentare given in Technical Note 2561.

Creep

In the design of structures required to oporat~ at ele-vated tempemtures, kno-wleda~of the characteristics ofmaterials at thesetemperatures is eesentird. One of thephenomena associated with elevated temperatures isthat of creep, the time-dependent clistortion of metalsunder stress. It is felt that a better understanding ofcreep phenomena will allow the more eficient use ofmaterials in design. The experimental dtittiavuiluble,however, are in general not sufficiently detailed nor dothey cover a wide enough range in conditions to be effec-tive for use in design, and although emeral theories havebeen advanced to account for creep behavior, thesetheories are not complete enough to be of much help. Astudy of the fundamental mechanism of the creep ofmetxdshas been initiat@ therefore, at the Batt& Me-morial Institute. Before proceeding with the experi-mental work, Battelle conducted a survey of the exist-ing lmowledge in the field. This survey, released asTechnical Note 2516, treats the creep of both single-crystal and polycrystalline metals. The modes of de-formation in short-time, low-temperature tests are con-sidered, as well as the varioue theories which purport toexplain the behavior of metals during creep. Battelleis now obtaining experimental data on the creep of 2Sahuninum alloy over a wide temperature range andcomparing these data with available theories. Shouldthe data conform with none of these,eflorte will be madeto develop an appropriate theory to try to account forall the obserred phenomena.

Stress Corrosion

The Armour Research Foundation in its inveetigti-tion of stresscorrosion has developed equipment whichwill permit observation and recording of the relativepotentials of various regions near the surface of a me-tallic specimen during corrosion. By means of thisequipment.it is possible to locate the anodic and cathodicareas on a corroding surface nnd identify such areaswith the corresponding metallurgical feature. Tech-nical Note 2523 presents a d=ription of this equip-ment amd describes the techniques developed for the

interpret ation of the data obtained. The equipmentis now being USCC1to investigate the stress corrosion

REPORT NATIOA’AL ADVISORY COMMITTEE FOR AERONAUTICS 33-

mechanism of a high-purity binary alloy, aluminum—+@ercent copper.

Corrosion

The inrestigat ion of the corrosire properties ofmetalsjointly sponsored by the NAC.1, Bureau of &eo-nautice. and the Air Mat4riel Command has continuedat the National Bureau of Skmdards. The purpose ofthis immstigation is to determine the rate of corrosionof materiaIs used in aircraft when exposed to marineatmosphere and tidewater. During the past year data-wereobtained from exposure tests on galvanized steelstitched-ahnirmrn aIIoys. These are reported in Teeh-nical Note 9299. The effect of hot dimpIing on thecorrosion of ahuninum alloys 75S-T6 and alcIad76S-T6 was ewduated and reeds were also obtainedfrom corrosion tests of magnesium alloy ZK60.

Hydrogen lhnbrittIement

A fundamental study was conducted at the BatteIIeMemorial Institute on the mechanism by -whichhydro-gen enters metals, particularly aircraft steels, causinghydrogen embritt~ement during chemical or electro-chemical action. Several know-nmethods of controllingthe inlet and exit of hydrogen in steel were correlatedwith the known chemical beharior of atomic and moleo-ular h@rogen. By means of this correlation it wasfound possible to select suitable reagents which aig-nificantly decreased h-j-drogen permeability and em-brittlenlent of steel during cathodic pickIing operationsin dihlte suIfuric acid. The same data show that theW&ion of hydrogen in steel and the freedom of exitof h~drogen are important in determini~~ the extentof embrittlement and tdso that these phenomena arechemical in nature rather thnn mechanical.

.Adhesi\-es

In the manufacture of aircraft the bonding of sand-wich panels. consisting of aluminum aIIo.yebonded tovarious core materiaIsYand the bonding of ahnninumto itself by means of adhesives offers several importantadmmtages over other methods of faeteni~u: and thereis comGiderableinterest at the present time in such proc-esses. There is a need. however: for an adhesive ade-quate for use at.elevated temperatures. ‘Ilk led to theinveeti~~tion at Forest Products Laboratory on the ef-fects of temperature on the bond strength of joints fab-ricated with adhesives. The evaluation of the perform-ance of commercially available metal bonding adhesivesin the temperature range of —70° to 600° F. has beencompletecl. The e~aluation of the relative merits of themmeri~ilsis based upon the data obtained from tensile

tests of joints both .mhen tested immediately uponreaching the test temperature and after sereral days’exposure at the test temperature.

PIastics

The investigation of the 10S of strength of plasticglazing as a result of craz~~ has continued at the Na-tional Bureau of Standards. Since plastic glazing isused in the windows and canopies of airphmes, thisproperty is of coneiderable interest to the aircraft in-dustry. The meager information on the subject waswqanded during the past year by two reports from theNatiomd Bureau of Standarda. In one of these, Tech-nical hTote2444, the loss in strength of several gradesof Pc@nethyl methacrylate due to stress solvent craz-ing is discussed. In this i.mestigation tensile speci-mens were artificially crazed by applying benzene to —.the central portion of the specimen while it was understress. Among the factors studied were the sheet-to-eheet variability of crazing specimens and the relativeeffect of a few large crazing cracks compared with morenumerous finer cracks. Applying benzene to the speci-mens caused a less of strength of approximately 30 .percent in all of the materials.

An investigation was completed at the NationaI Bu-reau of Standards on the strength of hext-reeietantlaminates up to 375° c. The flesural properties ofsamples of glaas fabric huninates such as are uss inradomes were determined for several loading cycles at

elevated temperatures. The laminates teated werebonded tith various resh=, including unsaturated-

pol@er, acrylic, ficone, phenoIic, and mehiro.ine

types. Tests of a ticone resin laminate showed it to be

superior to tlm other laminates in retention of ffexu.ralproperties at temperatures of ‘250° ~. or higher (Tech-

nic~ Note 2266). At temperatures of 300° to 325” C.this laminate retained at least 60 percent of its initiaIffexural strength and oyer 50 percent of its initialmoihdus of elasscity.

MaterisIs Evacuation

The light weigh$ high-strength, corrosion-resistant,and favorable elevated-temperature properties of titan-ium ha~e aroused interest in the poseibiIity of usingthis material for aircraft- structural applications. Inorder to indicate the potentialities of this material? anev-duation of titanium including comparisons with se$-eral other aircraft materials has been made for typicalstructural applications. The procedure developed forthis purpose protidea a general method for determiningthe structu.nd eficiency of a material for a particularstructural application (Technical h’ote 2269);

34 REPORT NATIONAL ADYL5.ORYCOMMITTEE FOR AERONAUTICS

OPERAT~G PROBLEMSInvestigations have been continued of the n~eteorolog-

ical conditions adverse to the performance and safetyof flight, means of accurately measuring air speed andstatic pressure at transonic and supersonic speeds, prin-ciples of design of aircraft systs-ns for coping withnatural icing conditions, and methods of improvingaircraft safety. Research on atmospheric turbulence,aircraft ditching, and air speed measurementhave beenconducted by the Langley Aeronautical Laboratory,while studies of natural icing conditions, aircraft ice-protection systems, and aircraft crash ties have beenconducted by the Lewis Flight Propulsion Laboratory.The Ames Aeronautical Laboratory has also done lim-ited work in the field of aircraft icing. The work ofthe NACA laboratories has been supplemented by re-search conducted by several nniversitiee under con-tract to the NACA.

The practice of holding technical conferences withindustry and mifitary representatives was extanded tothe field of operating problems. A conference on someproblems of aircraft operation was held at the LewisFlight Propulsion Laboratory in the fall of 1950. TheCommittee on Operating Problems is responsible forthe guidance of the operating problems research pro-gram. It is aided in specialized aspects of this pro-gram by its subcommittees, the Subcommittee onMeteorological Problems, the Subcommittee on IcingProblems, and the Subcommittee on Aircraft FirePrevention.

AIRCRAFI’ OPERATION

Air Speed and Altitude Measurement

A systematic investigation of the static-pressureerrors ahead of wings and fuselage noses of two low-wing airplanes was conducted in flight (Technical Note2311). The variation of the etatic-pressue error withposition of the static-pressure tube, located at severalpoints from 0.25 to 2.0 chord lengths ahead of the wingtip and 0.5 to 1.5 fuselage diameters ahead of the nose,was determined over a speed range from the stall upto a maximum of 265 miles per hour. At low lift co-efficients?the error decreased with increasing lengthsahead of the wing or fuselage, with variation in errorover the lift-coefEcient range being approximately thesame for the 1~2-diameter fuselage-nose installationand the 1-chord wing-tip installation.

For present-day high-performance airplanes havingthe capabilities of marmvering to high angles of attackat supersonic speeds, the need has developed for rigidair-speed tubes which will measure total and staticpressurescorrectly under thtweconditions. As a meansof determining the optimum design of total-pressure

tubes, a series of wind-tunnel tests has been conductedto determine the etTectof inclination of the air streamon various types of total-pressure tubes over a widerange of angle of attack through th~ subsonic andsupersonic speed ranges. Preliminary testson 39 tubesat subsonic speeds are reported in Technical Note 2381.Subsequent tests of 20 of these tubes at supersonicspeeds nre reported in Technical Note 226L The re-sults of the tests showed that the tube -which remainedinsensitive o~er the greatest range of angle of attack, =both at subsonic and supersonic speeds, was a shieldedtotal-pressure tube dasi=~ectfor end mounting on a hori-zontal boom. The range of angle of attack over whichthis tube remained insensitive (to within 1 percent ofthe impact pressure) was &41.5° at subsonic speeds and&37° at supersonic speeds. From the results of thetestsof the other tubes, the effects of such desi=mfnctorsas external shape, internal shape, and configurationof total-pressure entry were evaluated, and the effectof Mach number on the performance of the varioustubes was determined. Studies were also conducted ofeffects of position and airphme coniigurrttion on themeasurement of air speed and Mach number in thetransonic speed range. The applicability of usingpressures on a cone as a measure of angle of attack attramonic speeds was also investigated.

Ditching

The investigation of the ditching characteristics ofcivil transport-type aircraft was completed with thestudies of the behavior of the Convair-Liner. The rec-ommended ditching procedures follow those for othertransport types, touchdown being made at fwirly highangle of attack with flaps clown and landing gear up.The behavior de.pendeupon the manner in which theflaps fail, the maximum deceleration being somewhatgreater if the.flaps rotnte to neutral rather than beingcarried away.

AERONAUTICAL METEOROLOGY

Prediction of Low.Level CIear-Air Turbulence

Preliminary investigation of the meteorological vari-ables associated with turbulence in clear air within theearth’s friction layer led to the development of a simpleempirical relation for estimating the intensity of theturbulence. The correlation of the observed gust ex-perience of an airplane -with various combinations ofmeteorological variables showed that a simple productform of the intensity of solar radiation and the averagewind shear layer below the first discontinuity in tenl-perature hpse rate gave very good results for condi-

REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS 35

tions similar to those of the tests. This rehition ac-counts for seasonal variations in turbulence intensitybut, because of its simplicity, cannot discriminate be-tween differences in turbulence intensity resulting fiornvariations in flight altitude or diurnal ~ariations inturbulence. The relationship has been established onlyfor the limited conditions of terrain and meteorologicalsituations during the fights in the vicinity of Wilming-ton, Ohio. Sign.Meant differences in these conditionswill alter the rehitive importance of the meteorologicalvariables considered.

Radar Detection of Thunderstorm Turbulence

Evaluation of the usesof airborne radar for detectionof turbuknt areas in thunderstorms tvttsconducted bythe Kaw with the assistanceof the Langley Laboratorystaff. The presentation of areas of light rainfall andheavy rainfall on the radar PPI scope allowed pre-liminary correlation of the gust experience of an air-plane with the indicated rainfall gradient. The Iimitedresults so far obtained indicated that possibilities ofreducing the number and severity of the gusts likelyto be encountered in a thunderstorm -weregood if theareas of high rainfaII rate gradient were avoided.

Suxface Wind Instruments

A wind-tunnel calibration of instruments for deter-mining wind -relocity and direction -wasconducted forthe Signal Cimps, United States Army. A threecupanemometer was calibrated for measuring wind veloci-ties up to 200 miks per hour. Tvio pressure-type com-bined wind-velocity and wind-direction indicato~~ werealas tested. One with four equally spaced orifices onthe perimeter of a circular dkk was tested up to 100miles per hour, and another consist@ of a pitot-statichead mounted on a pivoted -weathervane was tested upto 250 miles per hour.

AIRCRAFT ICING

Research is continuing at the Lewis FIight Propul-sion Laboratory and the &nes Aeronautical Labora-tory in an effort to estabkh the meteorcdogica.1condi-tions that make up the ici~u cloud so that ~his kriowl-edge may be appIied toward the efficient design of air-craft ice-protection systems.

Cb.racteristics of the Icing Cloud

The meteorological aspects of the icing cloud are be-

ing studied extensively in fight and laboratory inwstl-

gations to determine what values of meteorological fac-

~ors exist in the atmosphere and how these data canbest be utilizecl to desi~ efficient types of ice-protec-

tion systems for the various aircraft components. Ten-tative recommended values of meteorcdogical factorsto be considered in the design of aircraft ice-protectionsystems previously published (Technical h’ote 1855)have been supplemented with data collected by thehTACA and other agencies during the 194-849 and1949-50 winter seasons and have been analyzed to pre-sent a method for the selection of desibgncriteria, The -data are summarized to give frequency of occurrence of —icimg conditions according to liquid-water content and _.drop size and further to indicate that statistical rela-tions do exist between liquid-water content, mean ef -fecti~e droplet diameter, temperature, and pressure alti- ___tudes. A considerable amount of additional data isneeded before a purely statistictd amdysis can be at-tempted; home~er, this accomplishment can be madepossible only if the ei70rts to design suitable meteor-ological instruments are succeesfcd.

The Lewis Laboratory has de-relopedand reported-ona reliable pre~-type icing-rate meter that wiIl aut~maticalIy record icing rate, airspee~ altitude, and timein supercooled clouds. Evaluation testson research andcommercial aircraft indicate that the use of this instru-ment to collect a large amount of data for a statisticalanaIysis is practical. The operation of the instrumentis based on the creation of a differential pressure be-tween an ice-free total-pressure system and a tobal-pressure system in which small total-pressure holesvented to static pressure are allowed to phg with iceaccretion. At a &cd value of ice accretion, the differ-ential pressure operates an ekctrical heater that d~-icesthe totaI-pressure holes. The resulting cyclic process-iaries with the intensity of the icing and serw.s as ameasure of the icing rate. The simplicity of this oper-ating principle permits automatic operation upon en-countering m icing condition and relative freedom frommaintenance and operating problems. The completeunit -weighsonly 18 pounds. Visual indications of theicing intensity are made available to the piIot by pe-riodic flashing of a light on the instrument panel.

bother instrument pre~ionsly developed as a clouddetector has been further investigated to provide a sim-ple means for measuring liquid-water content in above- __and below-freezing clouds. The instrument consists ofa small cylindrical element so operated at high surfacetemperatures that the imp@pment of cloud dropletscreates a significant drop in surface temperature. Pre-liminary calibrations of this instrument have indicatedthat improvements are expected to make it a reliableinstrument for recording the important meteorologicalfactor of Iiquid-water content.

Liquid-water content, droplet size, and temperaturedata measured in predominantly stratiform clouds dur-ing the last two ic~~ seasons have been presented in

36 REPORT NATIONAL ADVISORY

Technical Note2306. Theaverage liquid--iwdercontentof a cloud layer, as measured by the multicylinder tech-nique, seldom exceeded two-thirds of that vvhlch couldbe released by adiabatic lifting. The horizontal andvertical extent of icing conditions and the relation ofthe existenceof supercooled clouds to cyclonic areas andprecipitation regions are indicateclo

The Lewis Laboratory is continuing to make progresstoward understanding of the fundamental processes in-volved in the formation of the icing cloud and in metho-ds for its prediction. Part of this study has been acontinuation of the investigation of spontaneous freez-ing temperatures of supercooled water droplets of thesize found in the atmosphere. A statistical explanationof the previously reported investigation of spontaneousfreezing temperature of water droplets (TechnicalNote 2142) has been published in Technical Note 2234.The statistical theory is based on the presence of anassumed crystallization nuclei distribution suspendedin the water and results indicate that small dropletsmay be supercooled to lower temperaturesthan the largedroplets, The probable distribution curves of spon-

COMMITTEE FOR AERONAUTICS

taneous freezing temperatures for water droplets of

various sizes are given and compared with the experi-mental results.

Propeller Ice Protection

The Ames Laboratory has completed antilytical andexperimental investigations of the effect of ice forma-tion on propeller performance (Tschnicul Note 2212).The experimental measurements were made duringflight in natural icing conditions, wherein the analysisconsisted of tininvestigation of changes in blade section —.aerodynamic characteristic caused by ice formationand the resulting propeller efficiency chtmges. The re-sults indicated that efllciency losses can generally beexpected to be lessthan 10 percent with maximum hssesas high as 20 percent to be expected only rarely. Theeffects of ice accretion on airfoil section chnructeristicsat subcritical speeds, the effect of kinetic heating on theradial extent of ice formation, and the influence of theefficiency 10s on the pilot’s adjustment of engine findpropeller controls are also discussed.

RESEARCHPUBLICATIONS

TECHNICAL REPORTS

No.951. Use of Source Distributions for Evaluating Theoretical

Aerodynamics of Thin Finite Wings at Supersonic~peedS. BY JOhn C. IOward.

952. Direct Method of Design and Stress halysis of Eot8tingDlaks with Temperature Gradient. By S. S. Manson.

955. AttalnabIe Circulation about Airfoils tn Cascade. BYArthur W. Goldstein and Artur Maser.

954. Two-Dimensional Compressible INOWin Centrifugal Com-pressors with Straight Blades. BY John D. Stanltz andGaylord O. 3!llIts.

936. Application of RadiaI-Equilibrium Canditiou to Ax[al-FlowCompressor and Turbine Design. By Chung-Hua W’uand Lincoln WoLfenatein.

956. Linearized CompresslbIe-E’low Theory for Sonic FlightSpeeds. By Max. A. Heaslet, Harvard Lomax, andJohn IL 8preiter.

957. The Clllculatlon of Downwash Behind Supersonic Wings\\tithan Application to Triangular plan ~Or’ms. ByHarvard Lomax, Lama Nuder, and Max, A. HeasIet.

95S, Lamlnar Mixing of a Compressible Fluid. By Dean R.Ohnpman.

959. On*Dimenslonal Flows of an Imperfect Diatomic Gas.By A. J. Egger& Jr,

960. Determination of Plate Compressive Strengths at Ele-vated Temperatures. By George J. Helrnerl and Wil-Iiam M. Roberts.

961. The Application of Green’s !Cheorern to the Solution ofBoundary-Value Problems in Linearized SupersonicWing Theory, BY Max A, Heaslet and Harvard Lomax.

962. The Aerodynamic Forces on Slender Plane- and Crm3-form-Wh.vg and Body Comblnaticme. By John R.Spreiter.

Xo.963. Investigation with an Interferometer of the Turbulent

Mixingof a Free SupersonicJet. By Paul B. ~ood-erum,(leorgeP. wood, andMauriceJ, Bremort.

964.The Effectsof Variationsin BeYnol&Numberbetween3.OXIv and 25.OX10’ upon the AerodynamicCharac-tellstksof a Numberof NACi46-SerksAirfoilSectIons.By LaurenceK. Loftln,Jr., and ViWllam J. BursnalL

065. The LougitndinaI Stability of Elastic Swept Wlng5 atSupersonic Speed. BY C. W. FrIck and R. S. Chubb.

966. Flutter of a Uniform Wing with an Arbitrarily PlacedMass According to a Differential-llquatlon Analysis anda Comparison with Elxpcwiment. BY Hurry L. Runyanand Charles E. WrMdrLS.

967, EIastic and Plastic Buckling of Simply Snppnrted SoIid-Core Sandwfch Plates in Campreseion. By Paul Seldeand Elbridge Z. StovrelL

96S. Investigation at Lmv Speeds of the Effect of Aspect Ratioand Sweep on Rolling Stability Derivatives of UntaperedWings. By Alex Goodman and Lewis R. Fisher.

069. Some Theoretical Low-Speed Spnn Loading Characteristicsof Swept Wings in Roll and Sideelip. By JOhII D. Bird.

970. Theoretical Lift and Dampingin Roll at SupersonicSpeeds of Thin Sweptback Tapered Wings with Stream-wise TIPs, Subsonic Leadtng Edges, and SupersonicTrailing Edges. By Frank S. Malvestuto, Jr., Kennethhfargolis, and Herbert S, Ribner.

97L Theoretical Stability Derivatives of TMn SweptbackWings Tapered to a Point with Sweptback or Swept-forward Traillng Edges for a Liml ted Range of Super-sonic Speeds. BY Frank S. Malvestuto, Jr., aud Ken-neth Margolis.

972 The IMfeet of Torsional Flexibility on the RcJllng Clnw-acteristics at Supersonic Speeds of Tapered UnsweptWings. By Warren A. Tucker and Robert L. Nelson.

REPORT NATIONAL ADVISORY COM&UTTEE FOR AERONAUTICS 37

s+>.973. Flight Investigation of the Effec%of Tarious VertfcaI-Taii

Modidcations on the D1rectionai Stabflfty and OontrolCharacteristics of& PropeLier-Dri~en Ffghter Airplane.By HaroId L Johnson.

974. The SupersonicM-mow Compressor.By ArthurKan-txowftz.

975.SmaiiBendfngand Stretchingof sandwich-TyPeShe&.By EricRefssner.

976.LfnearTheory of Boundary Effects in Open ‘iVfndTnnneIstith Finite Jet Lengths. By S. ~atzoff, OIMordS.Qardner,Leo Diwsmlrnckjand Ikr&un ~. Eiaeustadt.

~. FrequencyResponseof Lfnear Systemsfrom TransientData. By lfeivfnE. LaverneandAaronS. Bolraenbom.

97S.lfethod of Des&abMCascadeBlades wfth PresmibedVelocftyDfstrfbutionsin CompressiblePotentialFlows.By @orge R. Costello.

979.On Stabflityof Free ~ar BoundaryLayerbetweenParallelStreams. By 3fartfnLessen.

9.S0.General~gebrale MethodAppliedto ControlAnaiyslsofCompl~ EngineTypes. BYAaron S. BoksenbomandRkhard Hood.

9S1.Theoretiml AnaIyafs of Various Thrust-AugmentationCycles for Turbojet Engfnes. By Bruce T. Lundfn.

9S!2.Icing-Protection Requirements for Recfprocatlug-EngfneInduction Systems. By WiUard D. C!oles, Vern G. RoI-li% and Donaid R. lfulholland.

9S3. Line-Vortex Theory for ClaIcuIation of Supersonic Down-vmsh. By HaroId 311rels and Rudolph C. Haefeif.

9S4. Method for Determhing the Frequency-Response Char-acterhtfcs of an Element or System from the SystemTramqient Output Response to a Known Input FunctiomBy Howard if. Curfman, Jr. and Robert A. Gardfner.

9S3. A Radar Methxl of Oa,iibratfng Afrspeed Instaiiatfons onAfrplanes in Maneuvers at H&h Altitudes and at Tran-aonic and Supersonic Speeds. By John A. ZaIoTcfir.

9S6. The Re~ersibiIity Theorem for Thin Airfoils in Subsonicand Supersonic FioTv. By Olfnton E. Brown.

9S7. Equiilbrium Operating Performance of AxiaI-Fiow Turbo-jet Engines by Means of Idsalfzed Analysts. By JohnC. Sanders and Edward C. Chapfn.

9.SS. Cmnprtrative Drag Measurements at Transordc Speeds ofRectangular and Sweptback N.ACA 65-009 AfrfofLsMounted on a Freely Fallfng Body. By Charles ‘iv.Mathews and Jim Rogera Thompson.

9S9. Crftkai S-ss of Rfng-Stiffened Cyltnders fn Torston.By Manuel Stefn, J. L-yell Sanders, Jr., and HaroldCrate.

930. An Analysis of Supersonic Aerodynamic Heating withContinuous Fnel Injection. By E. B. Khnker and HBeese IveY.

991. The Application of the Statistical Theory of Hreme Vai-ues to GuM-Load Problems. By Harry Press.

992. Theoretical Compsrfson of Several Methods of ThrustAugrnentatton for Turbojet Engines. By Elldon W. HaiIand D. Cifnton Wficox.

993. An Introduction to the Physh?aI Aspects of HelicopterStablifty. By Alfred Gessow and Kenneth B. &ner.

9%?. &aiysIs of Spanwfse Temperature Dfstriimtion fn ThreeTYPI= of Air-CooIed l“nrb~e BIad& BY John N. B.Lfvfngood and W. Byron Brown.

965. BIockage Corrections for Thr@+DimeneionaI-Flow CIoaed-Tlmjat JT[nd Twels. Mth e~~efderaffon of the Eff@of Compressibility. By John G. Herrfot.

>-0.936. Free-Space Oscillating Pr=res near the Tips of Rotat-

fng Propellers. By HarveyH. Hubbardand ArtlmrA..-

Regier.997. Summary of Information Relarfng to Gust Loads on Air-

planes. By Phflip DoneIy.99S. Further Experiments on the Fiow and Heat Transfer fn a

Heated TurbuIent Air Jet, By” Stanley Corrsfn andMshlnder S. Uberof.

999. Imrestigatfon of the .X-AC-A443) (03)-03 ~d XAC~ 4-(3) (OS)-045 Twc-Blade PropeUem at Forward Mach _Numbers to 0.72tf to Deterrnfne the Effects of Compres-sfbfifty and Soiidlty on Performance. By John StacQEugene C. Draley, James B. DeIano, and kids Feldman.

1000. Calcuiation of the Aerodynamic Loading of Swept andCnswept Flesible Wings of ArbltralT StfKness. ByBhanldln W. Diederfch.

1001. Fundamental lilffects of Agfng on Creep Properties ofSolutfon-Treated Low-Carbon N–153 ~OF. By D. N. __Frey, J. W. Freeman, and & ELWhfte.

10022 On the Theory of Oscillating Afrfofis of Finfte Span fnSubsonic Compreasible Flow. By Eric Reissner.

1005. Anaiytkal Determination vf Coupled Bending-Torsion lY-brations of Cantiie~er Beams by 31eam of Station Func-tions. By Alexander Mendelson and Selwyn Gendier.

TECHNICAL NOTES‘

;%2. Apprcminmte Aerodynamic Intluencw Coefllcients for TWngsof Arbitrary Plan Eorm fn Subsonic Flow. By Frank-lin M’. Dlederich

2111. A Study of Water Pressure Dfatributions during LandfrIgswtth Special Reference to a Prlamatic ModeI Haring aHeavy Beam Loading and 30= Angle of Dead Rfse. ByRobert F. Smiley.

211T. Des@ and Appifcations of Hot-Vi%e tiemometers forSteady-State Measurements at Transonic and Suwr-son[c A-irspeeds. By Herman H. LawelL

21.20. Development and Preliminary Iwwatigatfon of a Methodof Obtafnfng Hypersonic Aerodynamic Data by FirfngModels through Hfghiy Cooled Gases. By Harold V.SonIe and Alexander P. SaboL

2123. Iimestigation of Tnrtmient Flow in a Two-DfmensionaIChanneI. By John Laufer.

2124. Spectrums and Dfffnsion fn a Round Turbulent Jet. ByStanley Cormfn and Mabinder S. Uberof.

2122. Improvements fn Heat Transfer for htf-Icing of Gas-Heated Airfofis wfth Internal Fins and Partltfons.By Vernon H. Gray.

212& Investigation of 75-3.UIIimeter-Bore CyUndrIcai RollerBearings at H&h Speeds. I—InftiaI Studfes. By E,Fred Macks and Zolton N. Nemeth.

2122. Method of Calculating the Latertil Motioms of .AfrcraftBased on the LapIace Transform. By Harry E. Murrayand Frederick C. C+rat.

2130. Caiculatfon of TraRsonfc Flows Past Thin AirfofIa by anIntegral Method. By Wilifam Perl.

2131. Bonndary-Layer Transition on a Coded 20° Cone at MachNumbers of L5 and 2.0. ~ ~c~rd s~e~.

2131 The Oa&datfon of lfodes and Freqn~cies of a M*WStructure from Those of the Unmodified Structure. ByEdwin T. Krusmvakf and Johu C. HoubolL

.-.1The missing nnmbers In the eerfse of TechrdeaI Notes were reIeased

beforeor after the period coveredby this report.

—

38 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

No.2133. Inveatlgation of Separation of the Turbulent Boundary

Layer. By C4,B. Schubauerand P. S. Klebanoff.2134. Comparlsonof Model and FuI1-Scale Spin Te9t Results for

(30AirpIaneDesigns. By Theodore Berman.2136. The Calculation of Downwash Behind Wings of Arbitrary

Plan Form at Supersonic Speeds. BY John CLMartin.2136. Theory of Helicopter Damping in Pitch or Roil and a

Comparison with Fiight Measurements. By Kenneth Il.Amer.

21S7. An Analysis of Base Pressure at Supersonic Veioclties andComparison with E~periment. By Derm R. Chapman.

219S. Analytical and ExpmimeutaI Investigation of AdiabaticTurbulent Flow in Smooth Tubes. By Robert G.Deissler.

21S9. Effect of Variation in Rivet Diameter and Pitch on theAverage Strew at Maximum Load for 24S-T9 and 75S-T6 Aiuminum-Alloy, Flat, Z-Stiffened Panels that Faiiby LocrIl Instability. By Norris F. Dow and WilliamA. Hi&man.

2140. l’heureticai Antisymmetric Span Loading for Wings ofArbitrary Plnn Form at Subsonic Speeds. By JohnDeYoung.

2141. Charts for Estimating Downwash Behind Rectangular,Trapezoidal, rmd Triangular Wings at SupersonicSpeeds. 13y Rudolph U. Haefel.i, Harold Mirels, andJohn L Cummings

2142. Photomicrographic Investigation of Spontaneous FreexingTemperatures of Supercooled Water Droplets. BYRobert CLDomch and Paul T. Hacker.

2143. Analysis of the Effects of Boundary-Layer Control on thePower-Off Land[ng Performance Characteristics of aLiaison Type of Airplane. By Elmer A. Horton, Lau-rence K. Lotiln, Jr., and Stanley F. Raciax.

2144. Effect of Chemical Reactivity of Lubricant Additives onFriction nnd Surface Welding at High Sliding VelocitiesBy Edmond E. Bisson, Max A. Swikert, and Robert L.Johnson.

2145. Lift-Cancellat Ion Teclmique in Linearized Supersonic-Wing Theory. By Harold Mirels.

2146. On the Effect of Subsonic Trailing Edges on Damping inRoli and Pitch of Thin Sweptback Wings in a SupersonicStream. By Herbert S. Ribner.

2147. Some Conicai and Quasi-Conical Flows in LinearizedSupersonic-Wing Theory. BY Herbert S. Ribner.

214S. Lamlnar-Boundary-Layer Heat-Transfer Characteristicsof a Body of Revolution with a Prewmre Glradient atSupersonic Speeds. By W’iliiam R. Wiml.mow and Rich-ard Scherrer.

2148. Investigation of Boundary-Layer Control to Improve theLift and Drag Characteristics of the NACA 6545 Air-foil Section with Double Slotted and Plain Flaps. ByElmer A. Horton, Stinley F. Racisz, and Nicholas J.Psradiao.

2150. Flight Investigation of the Effect of Transient Wing Re-sponse on Measured Accelerations of a Modern Tran&port Airplane in Roqgh Air. By C. C. Shutliebarger andHarry C. MickIeboro.

2151. Estimation of the Damping in RoII of Supersonic-Leading-Edge Wing-Body Combinations. BY Waven A- Tuckerand Robert O. Piland.

2152. Shear Stress Distribution AIong Glue Line Between Skinand Cap-Strip of an Aircraft Wing. By C. B. Norrisand L. A.Ringelstetter.

No.215& The Stability of the Oampreaaion Cover of Box Beams

Stiffened by Posts. By PauI Seide and Paul F. Barrett.2154. An AnaiyNe of the Autorotative Performance of a FIPlicop-

ter Powered by Rotor-Tip Jet Units. By Alfred Gewow.2155. Calculated Elngine Performance and Airplane Range for

Variety of Tnrbine-Propelier Engines. BY Tibor F.~agey and Cecil G, Martin.

2156. Theoretical CaIcuiations of the Lateral Force and YawingMoment Due to Rolling at Superwnic Speeds for Sw@pt-back Tapered Wings with Streamwise Tips. SupersonicLeading Edges. By Sidney M. Harmon and John O.Martin.

2157. Static and Impact Strengths of Riveted and S@-WeidedBeams of Alclad 14S-T6, Alciad 75S-T6, ml VariousTempers of A1clad 24S Aluminum AI1oY. By IL E.Gr@shaber.

2158. A General Integral Form of the Boundary-Layer Equationfor Incompressible Flow with an Applk?at ion to theCalculation of the Separation Point of Turbulent Lhmnd-ary Layers. By Neal l’etervin and Chia Ciliao Liu.

2159. On the Particular Integrals of the Praudtl-BusemannIteration Kquatlons for the Fimv of n CompressibleFluid. By Carl Kapian.

2160. Measurements of Section Characteristics of n 450 Swe!JtWing Spanning a Rectangular Low-Speed Wind Tunnelas Affected by the Tunnel Wails. By Robert E. Dannen-berg.

2161. TabLes of l’herrnodymmlc Fnnct ions for Analysis of Air-

2162.

2163.

2164.

2165.

2166.

2167.

2168.

2169.

2170.

2171,

craft-Propulsion Systems. By Veari N. Hull! and San-ford Gordon.

Invest Igat ion of Propert lea of AISI-Type 31OBA11oYSheetat High Temperatures. BY E. E. Reynoida, J. W. i?ree-man, and A, E. White.

CriticaI Stress of Plate Columns. BY John C. Houbolt andEibridge Z. Stowell.

Axial-kfomentum Theory fw’ Propellers ln CompressibleFlow. By Arthur W. Vogeley.

Method of AnaUw!s for Compressible INOWthrough MixedFiow Centrifugal Impeliers of Arbitrary Design. ByJoseph T. Hamrick, Ambrose Ginsburg, and Walter M.Osborn.

iMfect of Heat and Power Extraction on Turbojet-EnginePerformance. II—Effect of Compressor-Outiet AirBleed for Specific Modes of Engine Operation. By I{’rankE. Rom and StanIey L. Koutz.

Sonic-E’low-Orifice Temperature Probe for High-12as-Tem-peratureMeasurements. By Perry L. Biackshear, Jr.

Experimental Investigation of the Effect of Verticai-TaiiSize and Length and of Fuselage Shape and. Length onthe Stdic Laterai Stabiiity Characteristics of a Modelwith 45° %veptback Wing and Tall Surfaces. BY M. if.Quei.loandW’alterD. lvolhart.

~ind-TunnelInvestigationat Low Speedof a 4ti0swePt-back UntaDeredSemisPanWing of AspectRatio 1.59Equippedwith Vm~ous2&Percent-ChordF1ah Flaps.By HaroldS. JohnsonandJohnR. Hagermrtn.

Effectof InitialMixtureTenweratureon Flame Speedsand Blow-Off Limits of Propane-Air FIrimes. By Gor-don L. Dugger.

Investigation of a Two-Step Nozzle in the Langley 11-Inch Hypersonic TunneL By Oharlea H. McLelian,Thomas W. Williams, and Mitchei H. Bertram.

REPORT NATIOA’.fi ADVISORY COl~TTEE FOR AEEOXAU’TTCS ..39

No.2172. Lw,v-Speed Investigation of the Stalling of a Thfn, Faired,

DoubIe-Wedge Ahfoll with Nose FLap. By Leonard WRose and JCI~ ~ ~~.

2173. Density F1eIds around a Sphere at Mach >“umbers 1.30and 1.02. By PauI B. Goodermn and George P. We-d

~IT-I. ComPmISon of me ~rhnentaI Pressure Distributioncm an NACA 0012 Proiile at High Speeds with thatCakmIated by the Relaxation Method. By James L.ArMck.

!iI?if. Effect of an Unssept Wing on the Contribution of Un-svrept-TaiI Contlgurationa to the Low-Speed Statfc-and RoIIing-Stability Derivatives of a bIldwing Air-pIane Model. By Willfam Letko and Donald R. RIIey.

2170. An Analysis of the A-ormal Accelerations and Airspeedsof a Fow.Eu@ne Airplane T~ in Po#xvar Commer-ckd Transport Operations orI Trans-PacU3c and Carib-bean-South American Routes. By Thomas L. CoIemanand PmI W. J. Schumacher.

2177. Low-Speed Characteristics of Fonr CambereQ l&Percent-Thlck NACA Atrfoil Sections. By George B. 31c+%I-Iough and VWIiam M. Hatre.

217.S. Method for Determining Optimmn DPrislon of Power be-tween Jet and Propeller for M.admum Thrw=t Power ofa Turbine-PropelIer Engine. By Arthur M. Trout andE1don W. HaIl.

2179. Turning-Angle Design Rules for Constant Thickness Cir-ctdar-Are InIet Guide Vanes in Axtal Anrndar FIovr.By Seymour LiebIein.

21S9. Effectiveness of 3101ybdenum DIsmlfide as a Fretting-Cor-rosion Inhibitor. By Douglas Godfrey and Edmond E.BIsson.

2ML The Aerodynamic Forces and Moments on a 1,/10-Scale31cdel of a Ffghter Airplane in Sp!nning Attitudes asMeasured on a Rotary BaIance In the Langley .%FootFrea-Spinning TunneL By RaIph TV.Ston~ Jr., SangerM. Burk, Jr., and WilI1am Blhrle, Jr.

23S2. AnaIysls of Effect of Variations in Primsr~ ‘FartabIes onTime Constant and Turbine-Inlet-Temperature Over-shoot of Turbojet Engine. By Marcus F. Heidmann.

21S3. Analysis for ControI Application of Dynamic Character-istics of Turbojet EIngine with Tail-Pipe Burnfng. ByIJelvln S. E’eder and Richard Hood.

21S4. Investigation of L?requency-Response CharacterfsH@ ofEngine Speed for a T-@cal ‘l?urbim+prope]ler Engine.By Burt IL Taylor III, and Frank L. Oppenheimer.

21.S5. Analytical Determinate on of CoupIed Bending-Torsion Vi-brations of C%ntfle~er Beams by Means of StationFunctions. By Alexander iUendelson and SelwynGendIer.

21S0. Method for Determining Pressure Drop of Air Flowingthrough Constant-Area Passages for Arbitra~ Heat-Input Distributions. @ Benjamin PInke~ Robert N.h-oyea, and Michael F. ValerIno.

21S7. Bonding Investigations of Titanium Carbide with VariousEIements. By Waiter J. Eu.gel.

21SS. Experimental Irriestfgatlon of StWened CMcuIar CylindersSubjected to Combhed Torsion and Compre&=ion. ByJames P. Peterson.

21s3. The Development and Performance of Two Small TunnelsCapable of Intermittent Operation at Mach Numbersbetween 0.4 and 4.0. By Walter F. LWisey and WilNamL. Chew.

2100. The Use of an ~ncalibrsted Cone for Determination ofFlow AngIes and Mach Mrnbers at S@ersonIc Speeds.By 310rton Cooper and Robert A. Webster.

No.Z191. TheoreffcaI Investigation and Application of Tranaonic

SimMmity Law for Two-DbnensIonal FIo’iv. By W.l?erI and 31fIton XL Klein.

21922 A Surrey of the Flow at the PIane of the PrOpelIer of aTwin-Engine Airplane. By John C. Roberts and PaulF. Yaggy.

2193. Effect of Heat-CapacityLag on a Yariety of Turbine-NozzleFLoviprocesses. By RobertB. spooner.

2194 me N~CAOn-DampedV-G Recorder. By Mel Taback!H95.A FlightInvestigationandAnal@a of thehter~-OSCll- ._._

lation Characteristicsof an Airplane. By CarI J. . _.Stough and William M. KamTman.

2190. Ef@ct of Heat-CapacityLagon theFlowthroughObl@eShocklYrtw?s-Br E Reeselr~ andCharlesW. Cline.

219T.PressureD1strlbutionand DampingIn stead!ipitch atSupersonicMachNumbersof mat Swe@-Back~ingsHayingA1lEdgesSubsotdc.BYHaroldJ. l~alkeratillam B. Ballantine.

219%Slnterlng31echanismbetweenZirconiumCarbide andColumbium BYH.J. Hamjlrinand~. G.IMraan.

2109.~tid-Tunnel Investigationat Low Speedof the Lateraltintrd Characteristicsof an unswept~ntaperedSemi-span wing of &~p@ Ratio 3.13Equ[ppedwith Yari-ous 2&Percent<~ordPlain ~erons. BY Harold S.JohnsontincIJohnR. Hagerman.

2_X0.A StUG of Secon&OrderSup+rsonlc-FlowTlwm~. BYltilton D. VanDFke.

2201.llessurementof the 3fomentsof Inertiaof an Airplaneby a SimplifiedMethod. By HowardL. Turner.

22~. Effectof HeatandPowerlilxtractlonon Turbojet-EnginePerformance. 111-&E@tfcal Determinationof Ef-fectsof Shaft-PowerExtraction. By StanleyL. ~outzfReeceV. Hensley,andFrankE. Rem.

-22. Boundary-LaYerMmsurementaLn3.= by I&hch Super-sonicChanneL By PauI F. Britdch.

2204. Gust-Tunnel Inm?stigatton of a Wing Model with Semi-chord Line Swept Back OOO. By HaroId B. Pierce.

-22. Theoretical Supersonic Characteristics of Inboard Trall-lng-Edge FIaps Having hbitrary Sweep and Taper.31ach Lines behind FIap Leadfng and TraU.ing Edges.By JnEan H. Kainer and Jack E. Marte.

220s. GraPMcal Methti for Obtakdng FIOW FhXld in TWO-Dhnensfonal Snpersordc Stream to WMch Heat 1sAdded.BF I. Imlng PhkeI and John S. Seratlni.

2207. Analmds of TnrbuIent Ehw+C!onwction Bonndary Layeron Fiat Plate. By E. R. G. 13Wert and Thomas W.Jackson.

222S. AnaI@s of Shear Strength of Honeycomb Corea for Sand-wich Constructions. By Fred IYerfen and Oharles B.Norris.

2209. Free Oscillations of an Atmosphere in VThIch Tempera-ture Increases LinearIy with Hefght. By 0. L Pekeris.

2210. Impact-Pressure Interpretation in a Rarefied Gas at Super-sonic Speeds. By E. D. Kane and G. J. MaaLach.

2211. An Approximate Method of Calculating l?ressures in theTlp Regfon of a RecUmgular Wing of CLrcuIar-ArcSection at Supersotdc Speeds. By EL R. Csarnecki andJames X. 3fnelIer.

22L2. The Effect of Ice Formations on PropelIer Performance.By Carr B. Nee~ Jr., and Loren G. Bright.

2213. Aerod.mamfc Co@icients for an Oscillating AirfolI withHinged Flap, with Tables for a Mach Number of 0.7.By M. J. Turner and S. Rabinowitz.

40 REPORT NATIONAL ADVISORY COMMTTEE FOR AERONAUTICS

No.2214. Formulas and Tables of Coe8idents for Numerical Dif-

ferentiation with Function Values Given at UnequallySpaced Polnta and Ap@caffon to solution of PartlalDitTerential Equations. By Chung-Hua Wu.

2215. Compressibility C+mrectlon for Turrdng Angles of Axial-Flow Inlet Guide Vanes. By Seymour Lbldeln andDonald M. Stmdercock.

2216. Investigation of 76-Millimeter-Bore Cylindrical RollerBearings at High Speeds. H-Lubrl@tlon Studi*Effect of Ofl-Irdet Lucation, Angle, and Velodty forSingle-Jet Lnbrlcation. By E. Fred Macks and ZoltonN. Nemeth.

2217. Analysis of PlaneStrw Problems with Axial Symmetryin Strain-Haxdening Range. By M. H. Lee Wu.

2218, Diffusionof Chromiumin a Cobalt-OhromlumSolidSolu-tlons. By John W. Weetan.

Z216.TheDynamicLateralControlCharacterlstlcsof AirplaneModelsHavingUnsweptWlngewithRound-andSharp-Leading-EdgeSectiom, By James L. Haseell andCharlesV. Bennett.

2220.A Balsa-Dustl?echnlquefor Air-FlowVisuaWatlonandIts ADplkationto Flow throughModelHeltcoNerRo-torsin StaticThrust. By MarIonK. Taylor.

2221.Ecmat~onsandChartafor theRapidEstimationof HinKe-htomentandEffectivenessParametersfor Traillng-EdgeControlsHaving Leadingand TrailingEd@e SweptAtwadof theMachLines. By Kennit~L. Goin.

2222,A ?4ethodfor the Determinationof the SPanwiseLoadD1strlbutlonof a Flexible Swept Wing at SubsonicSpeeds. By Richard B. Skoog and Harvey H, Brown.

2223. Investigation of the Flow through a Single-Stage Two-Dlmensional Nozzle in the Langley n-Inch HypersonicTunnel. By CharIes H. McLellan, Thomas W. Williams,and Ivan E. Beckwith.

2224. Multiple-Film Back-Reflection Camera for Atamlc StrainStudies. By Anthony B. Marmo.

2225. Bending and Buckling of Rectangular Sandwich Plates.By N. J. Hoff.

2226. Theoretical Analysls of Osclllatlons in Hovering of Heli-copter Blades with Inclined and Offset ~aPPIW ~dLaggtng Hinge ~es. By M. Morduchow and l’. G.Hinchey.

2227. Relation between Intlsmmables and Ignition Som!ces inAircraft Environments. By Wilfred E. SCU1l.

2228. EtTects of ModitlcationE to the Leading-liklge Region onthe Stalling Characteristics of the NAUA 63A12 AirfoilSection. BY John & Kelly.

2229, The IMfect of End Plates on Swept Wings at Low Speed.By John M. Rlebe and James M. Watson.

2290. Synthesis and Purlflcatlon of Alkyldiphenylmethane Hy-drocarbons. 1—2-Methyldiphenylmethane, S-Methyl-diphenylmethane 2-Ethyldlphenylmethane, 4-Ethyldi-phenylmethane and 41sopropyldiphenylmethanc& ByJohn H. Lamneck, Jr., and Paul H. Wise.

2231. Comparison of Fatkue Strengths of Bare and AlcIad24S-T8 Aluminum-Alloy Sheet Specimens Tested at 12and 1,000 Cycles Per Minute. By Frank C. Smith, Wil-liam C. Brneggcnnan, and Richard H. Harwell.

2232. Stress and DistortIon Analysis of a Swept Box Beam Hav-ing Bulkheads Perpendicular to the Spars. BY IMchardR. Heldenfels, George W. Zender, and Charles Libove.

2238. Some Effects on NonIlnear Vartation in the Directional-Stabil!ty and Damping-in-Yawing Derivatives on theLateral Stability of an Airplane. BYLeonard Sternfleld.

No.2234. Statistical Explanation of Spontaneous Freezing of Water

Droplets. By Joseph Levine.2295. The Boundary-Layer and Stalling Characteristlca of the

NACA 64AO1OAirfoil Section. BY Robert F. Petersom2236. fllu~rsonic Flow around Circular Cones at Angles of At-

tack. By Antonio Ferri.2237. Correlations of Heat-Transfer Datu and of Friction Data

for Interrupted Plane Fine Staggered in Suc@6iveRows. BY S. V. Manson.

2298. EtTects on Longitudinal Stability and Control Character-istics of a B-29 MrpIane of Variations in Stick-Force andControl-Rate Characteristics Obtained through ~se of aBooster in the Elevator-Control System. By Uharles W.Mathews, Donald B. Talmage, and James B. Whitten.

222i9. Theoretical Investigation of Transonic Sirrdlarity for Bod-ies of Revolution. By W. Perl and Milton M. KlelR

2240. The Effect of Nonuniform Temperature Distributions onthe Stresses and Distortions of Stiffened-Shell Struc-tures. BY Richard R. Heldenfels.

%241.A Numerical Method for the Stress AnaIysis of Stfffcned-Shell Structures under Nonuniform Temperature Dis-tributions. By Rk!hard It. Heldenfeis.

2242. Analytical InvesUgatIon of Turbulent Flow tn SmoothTuk+s with Heat Transfer with Variable Fluid Prop-erties for Prandtl Number of 1. By Robert G. Deissler.

2243. Effect of Cell Shape on Compressive Strength of HexagonalHoneycomb Structures. By L. A, Rtngelstetter, A. W,VOSS,and C. B. NorrLs.

2244. A Comparison of Theory and Experlmcnt for High-SpeedIlee-ilIolwule Flow, By Jackson R. Stabler, G1en Good-win, and Marcus O. Creager.

2245. Calculation of Compressible Potential Flow Past SlenderBodies of Revolution by an Integral Method. By MiltonM. Klein and W. Perl.

2246. Method for I)eterrnlnlng Distribution of Luminous Emit-ters in Cone of Lamlnar Bunsen FIame, By Thomas 1’,Clark.

2247. A Comparison of the Lateral Controllability with Flap andPlug Ailerons on a Sweptback-Wing Model Having I?ull-Span Flaps. By Powell M. Lovell, Jr.

2248. Analys!s of the IkTects of DesQn Pressure Ratio per Stageand OtT-Deeign Ernciency on the Operating Range ofMultistage Axlrd-Flow Compressors. By Melvyn Savageand Willard R. Westphal,

2249. The Spanwise Distribution of Lift for Minimum InducedDrag of Wings Having a Given Lift and a Given BendingMoment. By Robert T. Jones.

2200. An Wlysis of the Applicability of the Hypersonic Similar-ity Law to the Study of Flow about Bodies of Revolutionat Zero Angle of Attack. By Dorris M. Ebret, VernonJ. Rossow, and Victor L Stevens.

2251. EMects of Mach Number up to 0.34 and Reynolds NumberUp to 8xl@ on the Maximum LIf t Coefficient of a Wingof NACA 66-Series Airfoil Sections. By G. CheaterFurlong and James El. Fitzpatrick,

2252, Formulas for Source, Doubleti and Vortex Dletributione InSupersonic Wing Theory. By Harvard Lomax, Max. A,Heaslet, and FrankIyn B. FuIler.

2258. On a Source-Sink Method for the Solntlon of the Prandtl-Busemann lterstion Equations in Two-DlmeneionalCompressible Ffow. By Keith C Harder and E, B.Klunker.

~~34. Rege~eratt)r-Deslgll St udy and Its Applies thm to Turi.)ine-Propeller Engines. By S. V, Manaon,

REPORT NATIONAL ADKtSORY COMMITTEE FOR AERONAUTICS 41

No.2235.

2256.

~i=

225s.

22(IQ.

222.

2oJ=j~.

2263.

2264.

.mJ5.

22i0.

Two-Dimensional Compressible Flow in Centrifugal Com-pressors w[th Logarithndc-Spiral B1adee. By GaylordO. IZllia and John D. Stanita.

Three-Dimmteion& Lhateady-Lfft Problems in High-SpeedFlight-Basic Concepts. By Harw@i Lom~ Max. AHeaaIet, and lhmklyn B. FnlIer.

Temperature Distribution In Internality Heated Wails ofHeat Exchangers Composed of Noncircular FIow Paa-sagea. By EL R. G. Eckert and George M. Iaw.

Synthesis of Cyclopropane Hydrocarbons from blethyl-c@opropyI Ketone. I—2-C!yclopropylpropene and 2-C@opropylpropane. By Vernon A. Shbey and P. H.mm?.

Synthesis of CycIopropane Hydrocarbons horn MethyI-cycIopropyl Ketone. 11-2-@elopropyl-l-Penten% m-uand tran8 2-CIyclopropyl-2-Pentene and 2-CycIopropyLpentane. By Vernon A. SIabey and P. H. VW&

Synthesis and Pnrtdcat!on of Some ADrylblpIwnyIs andAIkylblcyclohe@e. By Irrfng A. Goodman and PauIH. Wise.

lWnd-TunneI Inwattgation of a Number of TotaI-Prea-sure Tubes at H&h Anglea of Attack Supersonicspeeds.By WIIlam Gracey, Donald E. CoIetti, andWaiter R Ruw?IL

RoUing and Yawing Uoments for Swept-Back Wings fnS1deallp at Superaonlc Speeds. BY Seymonr Larnpert.

The Use of a Lnmhmacent Lacquer for the Wand Indi-cation of Boundary-Layer Tramstion. By Jackson R.Staider and Ellf.a G. SIack.

Airfoil ProtMa for llinlmum Pressure Drag at SupersonicVelociffea-General AnaErsfs with Application to LJne-ariaed Supersonic F1ow. By Dean R. Chapman.

NAOA VGH Recorder, By ~-ormanR. Richardson.Strengthof Heat-RC8LStSntLamlnstesup to 375”C. By

B. M AsitrodandXarthaL Sherman.IneIastIcColumnBehatior. By John H. Dnberg and

ThomasW. WiIder,HI.Tea~of Tw&BIadePropellersin theLangIeyS-EhotH1gh-

SpaedTunnelto DeterminetheEEecton PropellerPer-formanceof a ?&Wflcatfonof rnboardPitchDlstribu-tiom By JamesB. DeIanoandlJelrinM. CarmeL

A Strnctnral-EmcfencyEwdnationof TItanfumat NormalandEllevatedTemperatures.By GeorgeJ.HehnerlandPanlF. Barrett.

TheoretfcaIDemptngtnRoHand EoIUng Effact&mnw ofSIender Crnclf&n Wings. By Gaynor J. Adams.

fin. ~rther Studyof ~e~ ~~fer Wtieen s~~ SW.faces. ByJ. T. BurwellandC.D. Strang.

2272.~teti EUMCInstaMIity of Hat-SectionStrhtgersnnderCompressiveLoad. BYStanleyGo@nan.

!2H8.SimtlarityLaws for Transotic Flow about Wings ofFiniteSpan. By JohnR ~re~ter.

fir~. EXttion of the Theoryof OsciIIatingAfrfoRaof ~teSpanin SubsonicCom~rewibleFIow. ByErfcRefsener.

=5. A Surveyof StsbiIttyAnaIYslsTechniquesfor Automati-callyControlledAlrcraf~ By ArthurL. JonesandBen-@aln R Briggs.

22i6. Staticandli’atigueStrengthsof Hfgh-StrertgthMnminum-~0~ BoltedJObt& ByE.C!.Hartmann,MarshallHolt,and L D. Eaton.

227’7. IMecte of Compressibility on the Performance of TWOli’rdl-Scale HeIfcopter Rotors By PauI J. Carpenter.

No.227S. TheoretfcaI Symmetric Span Loading Dne to Flap Defect-

ion for Wings of Artitrary PIan Form at SubsonicSpeeda. By John DeYoung.

2279. Three-Dimensional C?ompresslbIe Lamlnar Bomdary-Layer FIow. By FrankUn K. 3foor&

2260. A ‘l%eoreffml AnaIyaLsof the ~ of Fuel Motion onAIrplane Dynamics. By Albert A. SchY.

22S1. DetaUed Computational Procedure for D@gn of CascadeBlades with Prescribed Velocity Distrlbutiona in Com-preaaible PotentfaI FIOWS. By George R Coatello, Rob-ert L. Cnrmninga, and John T. SinnettG Jr.

22S2. h improved Approximate Method for Calculating LfiDistributions Due to Twfst By James C. SiwdIs.

22S3. Method for CaIcuIatlng Lift Distributions for UnsweptWings with Flaps or Ailerons by Use of NonUnear Sec-tion Lift Data. By James C. SIvelIa -d Gertrude C.Wllst!rick.

226-L LU’GPltchfng MomenL and Span Load C!Mracterbtfce ofViYngsat Low Speed as =ect~ by T’ariaKon8 of Sweepand Aspect Ratio. By Edward J. Hopkins.

22S3. Damping fn Roll of Crnclform and Some I&dated Delta‘iVings at Supersonic Speeds. By Herbert S. Ribner.

22S6. PreUrninary InwXLgation of a New Type of SnperaonicIrdek By Antonfo Ferrf and LouLs M. NUCC1.

22s7. An Investigation of Pure Bending in the PIaatIc Range .–When Loads Are Not ParaUeI to a PrlnciPal Plane. BYHarry A. Vi-ilIiama.

226S. Estfrnation ofLow-SpeedLiftand Hh@-lfoment Param-eters for FuU-Span TraiIIng-Edge F1apa on LMtingSurfaces with and wkhout Smepback. By Jules B.Dods, Jr.

22S9. EIaatic constants for Corrngated40re Sandwich Plates.By Charlea Libove and Ralph E. HubluL

2290. A Method for Cak!nIat-tng Stresses in Torsion-Box Coverswith Cutouts. By R~ChSrd Roaecrans.

2291. Induence of ‘iTall BonndarY Layer npon the Performanceof an Axial-F’low Fan Rotor. By Emanuel Boxer.

22!32.Experiment.al Investigation of the HITecte of Support Ln- -.terference on the Drag of BMWS of Re~oIntlon at aMach Xumber of L& By Edward W. Perkins.

2293. The Physical Properties of Active Nitrogen in Low-DensityFlow. By James 3L Benson.

2294. Lfft and pitching Derlvaffvaa of Thin Sweptback TaperedWtngs wfth Streamwtse Tips and %baonlc LeadingEdges at Supersonic Speeds. By Frank S. Maheatuto,Jr., and Dorothy 3L Howrer.

2295. Chordwfae and Compremibiltty Corrections to SIender-Tt”tig Theory. By Harnird Lomax and Iaaa S1uder.

2296. Turbnlent Boundary-Layer Temperature Recovery Factorsfn Two-DimenaionaI Supersonic Flow. By MauriceTricker and Stephen H. MaaIen.

2297. ~ect of an Increase in Angle of Dead Rise on the Hydro-dynamicCharacteristicsof a Hi@-Ungth-Beam-RatioHulL By WaiterE. Whftsker,J’r. andPaulW. Br~cejJr.

229S.A Xoticaffon to Thin-AfrfoIl-SectionTheory,~ppllcableto ArbitraryAtrfoflSections,to Accountfor theE&actsof Thklmeason theLfft Distribution.By David Gra-ham.

2299.ExposureTesta of Galvan&&Steel-St.ftchedAIumhmruAlloys. By FredW Relnhart.

2300.Analyticaland HxperfmentalInw@&atfon of Effect ofTwiet on Vibrations of cantilever Beams. By AlexanderMendelson and SeIwyn GendIer.

42 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

No.2301. LlnefLrlzed Solution and General Phstic Behavior of Thin

Piate with Circular Hole in Strain-Hardening Range.By M. H. Lee’iVu.

2302. AGeneral Through-lHow Theory of Fluid Flowwlth Subso~ic or Su~ersonic Velocity in Turhmachines of Arbi-trary Hub and Casing Shapes. By Clmng-Hna Wu.

2903. Correspondence Flows for Wings in Linearized PotentialFields at Subsonic and Superaonlc Speeds. By SidneyM. Harmon,

2S04. Effect of Heat and Power Extraction on Turbojet-EnginePerformance. IV-Analytical Determination of Effectsof Hot-Gas Bleed. By Stanley L. Koutz.

2S05, An Aualytical and Experimental Investigation of the SkinFriction of the Turbulent Boundary Layer on a FlatPlate at Supersonic Speeds. By Morr!s W’. Rnbesin,Randall C!.Maydew, and Steven A. Varga.

2306, Meteorological Analysis of Icing Conditions Encounteredin Low-Altitucle Stratiform CloudS. By Dwight B.KIine and Joseph A. Walker.

2307. A Theoretical Method of Determining the Control Gear-ing and Time Lag Necessary for a SpecMed Dampingof an Aircraft Equipped with a Constant-Time-Lag Au-topilot. By Ordway B. Gates, Jr., and Albert A, Schy.

230& Vibratory Stresses in Propellers Operating in the FlowField of a Wing-Nacelle-Fnselage Combination. ByVernon L. RogaRo, John C. Roberts, and Merritt R.Oldaker.

2309. Charts for Estimation of Longitudinal-Stability Deriva-tives for a Helicopter Rotor in Forward FIight. ByKenneth B. Amer and i?. B. Qustafson.

2910, Generalization of Boundary-Layer Momentum-IntegralEquations to Three-Dimensional Flows Including Thoseof Rotating S~tem. By Artur Mager.

2311. Flight Investigation of the Variation of Static-PressureError of a Static-Pressure Tube with Distance Aheadof a Wing and a 17uaelage. By William G?racey and El-wood l?. Scheithauer.

2812. BeaMng Strengths of Some Aluminum-Alloy Permanent-MoId Castings. By E. M. Finley.

2313. The Eff&?ts of Mass Distribution on the Low-Speed Dy-namic Lateral Stability and Control Characterlstlmof a Model with a 45° Sweptback Wing, BY DonaldE. Hewes.

2314. Effect of Quadratic !l!erms in Differential Wuations ofAtmospheric Oscillations. By C. L. Pekeris.

2315. Supersonic Lift and Pitching Moment of Thin Swe@-back Tapered Wings Produced by Constant Vertical Ac-celeration. Subsonic Leading Edges and SupersonicTrailing Edges. BY Frank S. Malveztuto, Jr., and Doro-thy M. Hoover.

2316. Wind-Tunnel Investigation at Low Speed of Lateral Con-trol Characteristics of an Untapered 46° SweptbackSemispan Wing of Aspect Ratio 1.59 Equipped withVarious 2&Pereent-Chord Plain Ailerons. By Harold S.Johnson and John R. Hagerman.

2317. A~plications of Von K&rmdrt’s Integral Method in Super-sonic Wing Theory. By Chieh-Ohien Chang.

2318. Full-Seals-Tunnel Investigation of the Static-Thrust Per-formance of a Coaxial Helicopter Rotor. By Robert D.Harrlngton.

=19. Some Properties of High-Purity Sintered Wrought Molyb.denum MetaI at Temperatures up to 2,400° F. By R. A.Lcmg, K. O. Dike, and H. R. Bear.

NO.2320.EITects of Some SolutIouTreatmentsFollmvedl.wtinAg-

ing Treatmenton the Life of SmtillCastGas-TurbineBladesof a Oobalt-Chromium-Btise.klIoy. 1—EffwtofSolution-TreatingTemperature.By 0. YakerandC.A.Hotian.

2321.Anal@s of TemperatureDistributionin L1@d4001edTurbfneBlades. By John N. B. LIvingoodand W.ByronBrown.

2322.Creepof Lead at Vrtrlous Temperature.% By Peter W.Neurath and J. S. Koehler.

!2824. Fatigue StrengtlM of Aircraft Materials. Axial-LoadFatigue Tests on Unnotehed Sheet Specimens of 24S-T3and 75S-T6 Aluminum Alloys and of SAE 4130 Steel,By H. J. Grover, S, M. Bishop, and L. R. Jackson.

2325. Development of Magnesinm-Cerium ForgW Alloys forElevated-Tcmperrdure Service. By K. Grube, R. Kaiser,L. W. Eastwood, C. M. Schwartz, and H. C. Cross.

2326. Two-Dimensional Subsonic (jompre~ib~e FioTs ~~~t Arbi.trary Bodies by the Variational Method. By Chl-TehWang.

2327. Fatigue Testing Machine for Applying a Sequence of Loadsof Two Amplitudes. By Frank C. Smith, Darnley M.Howard, Ira Smith, and Richard HarwelL

2328. Methud for Determining Pressure Drop of MonatomicGases Flowlng in Turbulent Motion through ConstauLArea Passages with Simultaneous Frlctlon and HeatAddition. By M. F. Talerino and R. B. Doyle.

2329. Htgh-Temperrdure Protwtion of a Titanium-Ctirbicle Cer-amal with a Ceramic-Metal Coating Having a TiigitChromlnm Oontent. By Dwight G. Moore, Stunley G.Benner, and William N. Harrison.

2330. Water-Landing Investigation of a Model Having HeavyBeam Loadings and 0° Angle of Dead Rise. By A.Ethelda McArver.

2331. Wind-TunneI In~estlgation of a Number of Total-PressureTubes at High Anglea of Attack. Subsonic Speeds. ByWilliam Gracey, Willlam Letko, and Walter R Russell.

2382. Analysis of the Effects of Wing Interference on the TailContributions to the Rolling Derivatives. By WiiliamH. Michael, Jr.

2333. Transient Aerodynamic Behavior of an Airfoil Due toDifferent Arbitrary Modes of Nonstationary Motionsin a Supersonic Flow. By Chieh-Clien Chang,

2834, On Reflection of Shock Waves from Boundary Layers.By H, W. Liepmann, A. Roshko, and S. Dhawan.

2335. A Plan-Form Parameter for Correlating Certain Aerod-ynamicOharacteristice of Swept ‘il’ings. 13Y Franklin W.D1ederich.

2336. Some Theoretical Characteristics of Trapezddal Wingsin Supersonic Flow and a C!ompnrisou of Smwrnl Wlng-Flap Comllnations. By Robert 0, PiIand.

2337. Approximate Calculation of Turbulent Boundary-LayerDevelopment in Oompreesible Flow. By MauriceTucker.

2398. Experimental Investigation of Locnllzcd Regions of IQm-inar-Boundary-Layer Separation. By W1lIiam J.Bursnail and Laurence K. LoftIn, Jr.

2W9. Transonlc Flow Past a Wedge Profile vrlth Detached BowWave-General Analytical Method and Final CkdculatedResults. By Walter G. Vlncenti and Cleo B. Wagoner.

2340. A -Surveyof ~iethodafor DeterminingStabI1lty Param-eters of an Airplanefrom D~namIcFlight hleasure-menta. BYHarryGreenber&

REPORT NATIONAL ADVISORY COMM31TEE FOE AERONAUTICS 43 .–

h-o.2341. A Least Sqnare+s Cume Fitting Method with Applications

to the Calculation of Stability Coefdcients from Tran-sient-Response Dat& By Mamim ShInbroL

2342. Evaluation of Packed DistlUation Columns. I—Atmos-pheric Pressure. By ThaIne W’. Reynolds and GeorgeH. Sngimura.

2343. Comparison of Theoretical and Experimental Responseof a Singl&310de EIastic System tn Hydrodynamic Im-pact. By Robert W. Miller and Kenneth S?.Merten.

2344. Method for Calculating Dowmwash Field Due to LiftingSurfaces at Subsordc and Supersonic Spe@S. By Sid-ney M. Harmon.

2343.The Effectof an ArbltramSurface-TemperatureYmla-tlonalonga I’latPIateontheConvectiveHeatTransferin an IncompressibleTurbtdentBoundaryLarer. ByirorrisW. Rubesin.

2346.An IterativeTransformationProcedurefor XumericalSo-httion of FIutter and Similar Clharmteristlc-ValneProblems.BY~~ron L. Gosmrd.

2347.Effectof Asst Ratioand Swse@ackon tie Low-SpeedLateral Control Characteristk-sof untapered Low-&zzt-Ratio Wings Equippedwith RetractableMl-erons. BYJackFtschelandJohnR. Hagerman.

234S.Effectof AspectRatioon the Low-SpeedLateralControlCharacter[stksof UnsweptUntaperedLow-&wX-RatioWings. BYRodgerL. Naesethand William~.O’Hare.

23.+!).FluctuationsIn a Sway Formedby Two Im@n@ngJets.BYllarcus I’. Eekbnannand Jack 0. Hum@rer.

2350.On the Second-OrderTnnnel-Wall-C!onstrSctIonCorrwt~onsInTwo-DhnensionslCampreesibleFIow. By E. B.KtunkerandKeithC.Harder.

!?WL~n ExperimentalInvestigationof the E&ct of SurfaceHeatingon Boundary-LayerTransitionon a FlatPlatein Supel%onicFlow. BYRobertW. Higginsand Con.stantineC.Pappas.

2S52.Spin-TunnelIn~es&ation of the Effects of 31assandD1mensionslVarlatlonson theSpinningCharacteristicsof a Law-WingSingle-VerticaI-TaSlE1odelTypkal ofPersonal-OwnerAirplanes. BY Walter J. KEnarandIack H. ‘iWlsom

ZW3.ChartsandTablesfor U= in Calculationsof Downwashof Wings of ArbitraryPIan Form. By Ii’ranklinW.Diederich.

2334 A NumericalApproachto the InstabW&ProblemofMonocoqueC@lnders. By Bruno A. Boley, JosephlIempner,andJ. Wwers.

2356.Achrornatiaationof DebmScherrerLines. BYHansI!lls-steinand WanleySiegeL

2356.Two-DimensionalTranaordcmow Past Airfoils. BYYmg-HuaI~uo.

2367.iUethodfor @knWion of Ram-JetPerformance.BYJohnB. Henryand J. BuelBennett.

Z!5S.Effect of Yertkal-T&dl& and Lengthon the Yaw@StabilityOharactetlsticsof a ltodelHatig a 45°Swe@-back Wing. By ‘i’i’flIiatnLetlco.

2S59.l?loatingCharacteristicsof a P1afnanda Horn-BalancedRudder at Sph.m!ngAttttudesas DeterminedfromRotaryTestson a 310deIof a TypicaILaw-WingPer-sonal-OwnerACrplane.By WlllfsmBlhrle,Jr.

2360.Effect of TaiI Surfaceson the BaseDrag of a Body ofRevolutionatlJachNumbersof L5and2.0. ByJ. Rich-ard Spahrand RobertR. Dickey.

No.2361. TnrbrdeneIntenslty Measurements in a Jet of Ah’ Issuing - .=

from a Long Tube. By Barney H. LIttIe, Jr., and Staf- ._ford w. ‘i’ilIbur.

2362. Torsfonsl Strength of Sttffened D-Tubes. By E. S. ..- ,_Karanaugh and IV. D. Drinkwater.

2363. On the AppIfcation of 3fathieu Functions in the Theoryof Subsonic Compressible FIOW Past OscllItiting Alr-fofIs. By Eric Reiasner.

2364. On Two-Dimensional Flow after a Curved StationaryShock (with Special Reference to the Problem of D*tacked Shock Wares). By S. S. Shw

2365. Analytical Ewduatlon of Aerod~amic Characterist@? of ‘“Tnrblnes with Nontwlsted Rotor BIades. By V7illiamR. SIirka and David H. Siiwn.

2366. Friction at High SIMing Teloclties of Oxide Films on-Steel Surfaces Bcmndary-Lubricated with Stearlc-AcidSolutiome. By Robert L. Johnso& Marshall B. Peterson,and Max & Sw&erL

236i. General Plastic Behavior and Approximate SoIuttona ofRotating Disk in Strsin-Hardenbg R-. BY ~. H. .Lee TVu.

2369. Torsion and Tranmerse Bending of CantUerer Plates.By Eric Reissner and Manuel Stein.

2370. Matrfx Method of Determining the Lm@tudinal-StabHityC@efficienLsand Frequency Response of an Aircraft fromTransient FLfght Data. By James J. Donegan and ..__Henry A. Pearson.

237L Possible Application of Blade Bonndsry-Layer Controlto Improvement of Design and Off-Design Performanceof Axial-Flow Tnrbomtwhhws. By John T!. Sinnette,Jr., and George R. CosteIlo.

2372. Rectangular-Wind-Tmmel Blocking Corrections ~sing theVeIocit y-Ratio Method. By Rudolph W. HenseL

23i3. Practicalllethodsof CtdculatfonInro~redin the Experi-mentalStudyof an~ntopiIotandtheAntopuot-MrcrafrC!ombInatIon. By Lonls H. Smausand Elwood CStewart.

2374.Effect of InMal MixtnreTemperatureon FIarueSpeedof llethane-Air,Propane-Airand Ethylene-AirMx-

- tares. By GordonL. Dngger. -.

2375.OntheUseof CoupledlloclalFunclionsin mutterArialy.sis. BY DonaldS. WooIstonand HnrryL. RttnYan.

2376.Methodfor AnalyzingIndeterminateStructuresStressed —aboveProportionalWt. BYF. R Ste~bacher,C?.N.Gaylord,and W. K. Rey.

2377.Effect of Fuel Immersfon on Laminated Plastics. ByW. A. Crouse, Margte Oarickhoff and Margaret A. 17tsher.

237S. Automatic Control Systems SatfsfyLng Certain GeneralOrherions on Transient Behatior. By Aaron !3 Bok-aenbom and Richard Hood. — —

Z3i9. ti In~estigation of the Effects of Jet-Outlet tit-off &@e —on Thrust Direction and Body Pitchfng Moment. ByJames R. BIackaby.

23S0. Effectiwmess of Ceramic Ooatl.pgs in Reducing Corrosionof Five Heat-Resistant Alloys by Lead-Bromide Vapors.By Dwtght CLMoore and Mary W. Mason.

2381. Effect of HorizantaI-TaiI Location on Low Speed StaticLangitudlnaI StabLIfty and Dmuping b Pitch of aModeI Having 45” Sweptback TWng and TalI Surfaces.By Jacob H. Liechtenstein.

!28S3.EfTect of Horfzantal-Tafl Size and Tafl Length on Low-SP@X StaticLOWMUWMIIStabilityand Datnp!ng inPitch of a Model Ha~g 46° Sweptback Wing and TailSurfaces. By Jacob H. LichtensteLn.

44 REPORT NATIONAL ADVISORY COMMITTEE FOE AERONAUTICS -s

No.23S3. On a Solution of the Nonlinear Differential Elquation for

Transonic Flow Past a Wav+Shaped Wall. By CarlKaplan.

23S4. Preliminary Invest.lgatlon of Wear and Friction Proper-ties under Sliding Ckmditlons of Materials Suttable forCages of Rolling-C%ntact Bear@s, By Robert L. John-son, Max A. Swlkert, and Edmond E. Bisson.

23&. Fundamental Aging Effeds Influencing High-TemperatureProperties of Solutlon-Treated Inconel X. By D. N.Frey, J. W. Freeman, and A. E. white.

2368. Studies of Eiigh-Ter@erature Protection .of a TItanhnn-Uarblde Ceramal by Chromhun-Type Ceramic-MetalCoatings, By Dwight Cl. IUoore, Stanley G. Benner andWllliam N. Harrison.

23S7. Three-Dimensional Unsteady Lift Problems in High-Speed Flight-The Trlengular Wing. By HarvardLomax, Max, A. Heaslet, and Franklyn B. Fnller.

23S6. Axlsymmetric Supersonic Flow in Rotating ImpeIlere.By Arthur W. Goldstein.

23S9. Fatigue Strengths of Aircraft Materials. Axial-LaadFatigue Tests on Notched Sheet Specimens of 24S+9and 75S-T6 Aluminum Alloys and, of SAH 4130 SteeIwith Stress-Concentration Ii’actom of 2.0 and 4.0. ByH. J. Grover, S, hf. BIehoP, and L. R. Jackson.

2390. Fattgue Strengths of Aircraft Materials. Axial-IoadFatigue Tests on Notched Sheet Specimens of 24S-T3and 75S-T6 Alurolnuro AUOYSand of SAM 4130 Steelwith Strees-Concentration Factor of 5.0. By H. J.Grover, S. M. Bishop, and L. R. Jackson.

2393. Flow through Cascades in Tandem. By WilIfam E.Spraglin.

2397. Influence of Tensfle Strength and Ductility on Strengths ofRotating Disks in Presence of Material and FabricationDefects of, Seveml Typt?s. By Arthur G. HolnuA JosephE. Jenkins, and Andrew J. Repko.

23!3S.Synthesis of Cyclopropane Hydrocarbons from Methylcy-clopropyl Ketone. 111-2-Cyclopropyl-l-Butene, cfs andtram 2-Cyclopropyl-2-Butene, and 2-Cyclopropylbutane.By Vernon A. Slabey and Paul H. Wise.

2399. Applicability of the Hypersonic Similarity Rule to Pres-sure Dfatributions which Include the Effects of Rotationfor Bodies of Revolution at Zero Angie of Attack. ByVernon J. Roseow.

2402. Construction and USCof Charts in Design Studies of GasTurbines. By Sumner A1pert and Rose M. Litrenta,

2403. The Indiclal Ltft and Pitching Moment for a Shdting orPitching Two-Dimensional Wing Flying at Subeonlc orSupersonic Speeds. By Harvard Lomax, Max. A Heas-let, and Loma Sluder,

2405. Investigation of NACA 64,2-432 and 64,6-440 Airfotl Sec-tions with Boundmy-Layer Uontrol and an AnalyticalStudy of ‘l?hefr Possible Applications. By Ehner A.Horton, Strmley F. Itacisa, and Nicholas J. Parsdiso.

2407. Method of Analysis for Compressible Flow Past ArbitraryTurbomachine Blades on General Surface of Revolution.By Chung-Hua Wu and Curtis A. Brown.

240S. Approxhuate Design Method for Hfgh-Solidity BladeElements in Compressors and Turbines. By John D.Stanitz,

2409. summary of Methods for Calculating Dynarotc LateralStabillty and Response and for Estimating Lateral Sta-bility Derivatives. By John P. Campbell and Marion O.McKinney.

No.2410.Analytical Investigationof Fully Developed Laminar Flow

h Tubes with Heat Transfer with Fluld PropertiesVariable Along the Radius. BY Robert G. Deleeler.

2419. Flight Investigation of the Effect of Control CenteringSprings on the Apparent Spiral Stability of a Persunal-Owner Airplane By John P. Campbell, Paul .+. Hunter,Donald E. Hewes, and James B. Whltten.

2414. An Experimental Determination of the Critical BendingMoment of a Box Beam Stiffened by Peats. By Paul F.Barrett and Paul Seide.

2416, ~-eoretical “S&d~ of Some Methods” for Incensing theSmoothness of Fllght through Rough Air. By WilliamH. Phillips and Christopher C. Kraft, Jr.

241& Flow Separation Ahead of Blunt Bodies at SupersonicSpeeds. By W. E. MoeckeI.

2423. Theoretical Aerodynamic Characteristics of Bodies in aFree-Molecrde-Flow Field. By Jackson R. Staider andVernon J. Zurick.

242-4. Flfght Investigation of the Effect of Transient Wing Re-sponse on Wing Strains of a Twin-Fmgtne TrrmsportAirplane in Rough Air. By Harry C. Micklelwro andC. C. Shudlebarger.

2425. Plastic Stress-Strain Relations for KS-TO AluminumAIloy Subjected to BiaxiaI Tensile Stresses. BY JosephMarIn, B. H. Ulricl& and W. P. Hughee.

2431. Skin Friction of Incompressible !l?urtmlent Boundary LaY-ere Under Adverse Pressure Gradients. By Fnblo R.Goldechmled.

2435. Direct-IWading Design Charts for 756-TO AlumInum-Alloy Flat ComprWeion Panels Having LengItudlnai Ex-truded Z&Section Stiffeners. BY William A. Hickmanand N-orris F. Dow.

24W3.Heat Transfer to Bodies in a High-Speed Raretled-GaeStrewn. By Jackson R. Stadier, G1eH Gomlmin, tindMarcue O. Creager.

2441. Optical Methods InvoIvlng Light Scatterhg for MeasnrlngSise and Concentration of Condensation Particles inSupercooled Hypwaonic Flow. BY Enoch J. Durbln.

2443. The Similarity Law for Hypersonic Flow about S1enderThree-Dimensional Shapes. By Frank M. Hsnmker,Stanford E. Neice, and A. J. Eggers, Jr.

2444. IM%ct of StnX?s-Solvent Crszlng on Tensile Strength of

Polymethyl Methacrylate. By B. M. A~ilrod andMartha A. Sherman.

2490. Flight Investigation of Some Factors Affecting the Criti-cal Tail Loads on Large Airplanes. By Harvey H.Brown.

2502. Examples of Three Representative TYpes of Airfoil-Sec-tion Stall at Law Speed. By George B, McCulloughand Donald E. Gault.

2516. A Survey of Creep in Metals. BY A. D. Schwope andL. R. Jackson.

2623. Rotogenerative Detection of Corraslon Current& BYJoseph B. WA.ndrew, William H. Coiner, and HowardT. FrancIs.

2561. A Study of Poisson’s Ratio in the Yield Region. BYGeorgeGerard and Sorrel Wlldhorn.

REPORT NATIONAL ADVISORY COMMITTEE FOE AF.ROXA~CS ~x

TECHNICAL MEMoR-Al$immlS ‘

Citations to German reports in this list will use the folIowfngabbreviations where applicable:ZWB-ZentraIe f iir WissensclmftlichesBerichtswesen der Luft-

fahrtforschung des Generalluftzeugmeistem (German CentralPublication Odice for Aeronautical Reports).

FB-Forschungsbericht (Research Report).UM-Untersuchnngen und Mitteihmgen (Reports smd Memo-

randa ) .Iio.

1241. Basic Differential Equations in General Theory of ElasticShells. By T. S. VIasm. From Prikladnaia htatematikai ?JekhaniIm, VO1.8, 194+ pp. 109-140.

I.%& ~vdrodynamic Properties of Planing SurfaCeS and -gBoats. By N. & Sokolov. From !CSentral’u’ii AerO-gidrodinamichesi.rii Institut, Tsagi [CAHI Report] No.149, 1932, pp. 1-39.

124S. Investigations of Lateral Stability of a UIKie Bomb UsingAutomatic ControI Hwiing No Time Lag. By EL W.Spender. From ZWB, FB 1819, May 1943.

1250. Subsonic Gas FIow Past a Wing Protlle. BY S. A. CM!+tianovich and L W Yurlev. From PrikIadnaya Mate-matika i Wkhanika, VOL 11, No. 1, 1947, Pp. 10&l18.

IX&. FIight Performance of a Jet Power Plant. IH-OperatingCharncterLstfcs of a Jet Power PIant as a FrmCtion ofAltitude. By F. Vi’einig From ZVVB,FB lr~fi, NOV.1, 1943.

i260. Exact Solutions of Equations of Gas Dynamim. By L A.KiebeL From Prildndnaya Matematika i Mekhardca,vol. 11, 1947, pp. 193+98.

lfl%l. On the Theory of the Pro~agation of Detonation in GtM-eous Systems. By Y. B. z.eldo~kh. From 5urnaI 13x-pmimeutdnoi 1 Teoretfcheskol Ffaikti, Vol. 10, IWO, PP.542-568.

I-~9. ~fi~pn~e and Heat s~atifl~t~on. By E ~~chtig.

From Zeitschrift fitr Angewandte 31athematik und Me-chani& Vol. 15, No. 6, December 1935, PP. 313-338.

122. Contribution to the ProbIem of Buckling of OrthotropicPlate% with Special Reference to Plywood. By WilhelmThielemann. Prom Foraclmngsgemeinschaft Halle No.160,Ct9, Feb. 1945.

KHM.Isentropic Phnse Changes in Dissociating Gnses and thek.b?thod of Sound Dispersion for the Inw@igation ofH,]mogeneo~ Gas Reactions with Very High Speed. ByGerhard Damk6hler. From Zeftmhrift fflr IilIetr@chemie, VOL4S, No. z 1942, pp. 62-82.

1269. Isentropic Phase Changes fn DLslating Gascs and the2Jethod of Sound Dispersion for the Inresttgation ofHomogeneous Gas Reactions with Tery High Speed. ByGerhard DmukWIer. From ~ltachrift fGr M1ekt.M-chemie, ToL 48, No. 3, 1942, pp. 116-131.

12il. Effect of Intense Sound Wares on a Stationary Gas Flame.By H. Hahnemann and L. Elhret. From Z+?itschrift filrTechnische Physlk, No. 1O-U 1943, pp. 228-242.

1272. Critical Velocities of UN.racentrLfuges. By V. L SokoIov.From mmrnal l?ekhnlcheskol Fiziki (U. S. S. R.), VOL16. No. % 1946, PP. 463468.

1273. Resonauce Sound Absorber with Yielding lValL By S.X. Rzherkin. From Zhnrnal Teckhnicheskoi FizikiIU. S. S. R.), vol. 16, NO.~ l!)~, p~. 3S1-394.

1226. Sideslip in a Viious Cornprewdble Gas. By V. V. Stm-mins~v. From Doklady, Akademii Nauk (U. S. S. B.),~rOt.64, No. 9, 1946, PP. 76f&772.

~The mfseing numbers fn the serfea of Technfeal Memorendnme“werereleased before or after the ~eriod coveredby thfa report.

Ho.1278. General Solutlon of PrandtI’s Boundary-Layer Equatiom

By W. Mangier. From LiIfenthaI-Gesellschaft fiir Luft-fahrtforschung, Bericht Iti, @t. lWl, pp. 3-7. ‘

M!8L Unstable CapiiIary TVayes on Surface of Separation of TwoWscons Fluids. By V. A. Borodin and Y. F. DMya.ldn.From Priklmlnaya Mmematika i Mekhanika, VOL 13,No. 3, 1949, pp. 26i-2i6.

12.82. Theory of Flame PmpagatIon. By Y. B. Zeldovich. From5urnal Fizicheskoi Kldroii (U. S. S. R.), Vol. 2% 1948,pp. 2i49.

1283. Resistance of a Delta Wing in a Supersonic Flow. BYE. &Karpovich and F. I. Frmdd. From Prikladnaya Mat&matika i M&hanika VOL U, NO. & 1%7, PP. d%+%.

12.86. Method of Successive ~pprosimations for the Solution ofCertain Problems in Aero@mnics. By M. E. Shrets.From Prikladnaya MMematika i Mekhanika, VOL13, No.3, 1949, pp. 257-266.

12.97. Dependence of the Elastic Strain Coefficient of Copper onthe Pre-Trea-ent. By W. Kuntse. From Zeitachriftfiir J.tetallkide, VOL20, No. ~ 1922, pp. 145-1S0.

1288- The DiEhsion of a Hot Air Jet in Air in Motion. By W.SaabIewski. From LufKMmtforsehungsnnstaIt Her-msnn G&ing (EL V.), Braunsc!hvreig, Sept. 1W6.

1289. The Development of a HoIlovi Blade for Exhaust CAMTurbines. By H. Kuhhnarm. From ZWB, UM 788, Dec.liM3.

1291. On StabiIky and Turbulence of Fluid FIows. By WernerHeisenberg. From AunaIen der Physik, Tel. ‘7+ No. 15,1924 pp. 577-627.

1292. Laws of Flow in Rough Pipes. BY J. Nikuradse. FromVDI-170rschungsheft 361, Supplement to ‘T?orschung aufdem Geblete des Ingenieurwesensfl Series B, VOL 4,JuI~-Augusst 1933.

12$4 Exhaust Turbine and Jet PropnIsion Systems. BY K.Leistand El. ~LknscMI& From ZWB, ES 1069, May15, 1.939.

12%. Gas FloTv with Sbaight Transition Line. By L. V. Ovi-sinnnikov. From PrLldadnaya Matematika i Mekbanika,VOL~, 1949, pp. 537-542.

1296. On the Theory of Combustion of InitiaUy Unmised Gnses.By Y. B. ZeIdovich. From Zhurnal TekhnicheskoiFhrtkl. T’01.19, NO. 10, ~, pp. 119%1210.

U297. State and Development of Flutter Calculation. By &Teichmann. From Idlienthal-Gesellschaft fiir hrft-fnhrtforschnng, 13ericht 135, UMl, UP. 11-20.

1228. On tie Problems of Gas Flow Over an Infinite CascadeUsing Chaplygin’s Approximation. By G. .%.Bugaenko.From PriWadnaya Matematika f Mekhanika, VOL 13,No. ~, 1949, PP. 44%%6.

1299. Additional Measurements of the Drag of Surface Irregn-Iarities in Turbulent Boundary Layers. BY W. Tii-mann. From ZWB, lAi 6619, Dec. -W,19A

1305. On Ionization and Lumin-nce in Flames. By E. S3nger,P. Goer~ and I. Bredt. From original manuscript re-ceived June 17, 1949.

1810. Correction ‘Factors for Wind TunneIs of E1liptlc Sectionwith Partly Open and Partly Closed Test Section. BYF. RiegeLs. From LuftfahrKorschung, VOL 16, No. 1,1939, pp. 26-30.

lS12. Oalctition of the Bending Stresses in Helicopter RotorBlades. By P. de GuLllenchmiciL From Soc@t4 Na-tionaIe de Constructions Aarommtiquee du Oentre, RaPport He3-O.M+ Dec 23, 1949.

—-

.—

46 REPORT NATIONAL ADVISORY COMMiTTEE FOR AERONAUTICS

OTHER TECHNICAL PAPERS BY STAFFMEMBERS

Ault, G. MervLn, and Dentsch, G. C.: Review of NACA Researchon Materials for Gas Turbtne Blades. SAElQuarL Trans., vol.4, no. 8, July 1950, pp. 898-409; discussion, II. 409.

Becker, John V.: Results of Recent Hypersonic and UnsteadyFlow Research at the Langley Aeronautical Laboratory.Jour. Appl. Physics, vol. 21, no. 7, July 1050, pp. 619-628.

Carpenter, Paul J.: Hovering and ~w-Speed Performance andControl Characteristics of an Aerodynamk%ervocontrolledHelicopter Rotor System as Determined on the Langley Heli-copter Tower. Paper 50-SA+O, A. S. M. E., 1950.

Cohen, CL,and Kuczynsld, U. C.: Coetlicient of Self-DifCusion of(%ppm. Jour. APPL Phys., vol. 21, no. 12, Dec. 1950, PP.1888-40.

Dedrick, J. H., and Ku~skl, G, C.: 131ectrieal ConductivityMethod for Measuring Self-DifPuslon of Metals. Jour. Appl.Phys., VOL21, no. 12, Dec. 1950, pp. 1224-1225.

Deissler, Robert G.: Investigation of Turbulent I?1ow and HeatTransfer in Smooth Tubes, IncIudfng the Effects of VartableFluid Properties. Trans. A. S. hf. E., vol. 78, no. ~ Feb. 1951,pp. 101-107.

Dryden, Hugh L.: A Guide to Recent Papers on the TurbulentMotion of Fluids. AppL Mech. Rev., YO1.4, no. 2, Feb. 1951,pp. 7475.

Dugger, Gordon L.: The Effect of Inltlal Mixture Temperature onBurning Velocity. J’our. Am. Chem. Sot., vol. 7S, no. 5, MaylWl, p. 2898.

Dugger, Gordon L.: Flame Propagation. I. The Effect of InitialTemperature on Flame Velocities of Propane-.4ir Mixtures,Jour. Am. Chem. Sot., vol. 72, no. 11, Nov. 1950, pp. 5271-5274,

Frick, C. W., and Chubb, IL S.: The Longttudlnal Stability ofEllastfc Swept Wings at Supwxwnic Speed. Jour. Aero. Sci.,VOL17, no. 11, Nov. 1950, pp. 691-704.

Gerstein, Melvin; Levine, Oscar; and Wong, Edgar L.: FlamePropagation. IL The Determlnatlon of Fundamental BurningVelocities of Hydrocarbons by a RevLsed Tube Method. Jour.Am, Chem, Sot., Yol. 7S, no. 1, JSR. 1951, pp. 418-422.

Geasow, ALfred, and Amer, Kenneth B.: An Explanation of SomeImportant StabllHy Parameters That Influence HelicopterFlying QuaIities. Aero. Eng. Rev., Yol, 9, no. 8, Aug. 1950, pp.28-85.

Goodman, Irving A., and Wise, Paul H.: Dic@ic Hydrocarbons,I—2-AlkylbiphenyIs. Jour. Am. Chem. Sot., VOL72, no. 7, July20, 1950, pp. 8076-8079.

Goodman, Irving A., and Wise, Paul H.: Dlcyclic Hydrocarbons.11—2-Alkylbicyclohexyls, Jour. Am. Chem, Sot., VOL7S, no.2, Feb. 1951, pp. 850-851.

Guetafson, I’, B.: Deidrable Longitudinal Flying Qualities forHelicopters and Means to Achieve Them. Aero. Eng. Rev., VOL10, no. 6, June 1951, pp. 27-8S.

Hibbard, R, R,, and Pinkel, B.: Flame Propagation. IV. Corre-lation of Maxkmun Fundamental Flame Velocity with Hydro-carbon Structure. Jour. Am. Chem. Sot., VOL78, no. 4, Apr.IfEl, pP. 1622-1625.

HLmmel, Seymour C., and Krebs, Richard P.: The Effect ofChanges in Altitude on the Controlled Behavior of a Gas-Tur-bine Engine. Preprint S20, Inst. Aero. ScL, 1951.

HouboIt, John C.: A Recmrrent Matrix Solution for the DynamicResponse of Elastic Nrcraft. Jour. Aero. Set., vol. 17, no. 9,SepL 1950, pp. 540-550, 594.

Ivey, H. Reese: Hypersonic-Flow AnaIo~. Preprint 26S, Inst.Aero. Sci., 1950.

Jones, Robert T.: The Minimum Drag of Thtn ‘iWngs in Friction-leee FXOW. Jour. Aero. SCL,VOI.18, no. 2, Feb. 1951, pp. 7&81.

Kuczynaki, CAC., and Alexander, B. H.: Metallographic Studyof Diffusion Interfaces. Jour. AI@. Phys., vol. 22, m. S,Mar. 1951, pp. 844-849.

Lampert, Seymour: Conical Flow Methods Applied to UrdformlyLoaded Wings in Subsonic Flow, Jour. Aero, S&, vol. 18,no. 2, Feb. 1951, pp. 107-114, 188.

Landauer, Rolf: Oonductlvity of Cold-Worked Metals. Phys.Rev., vol. 82, no. 4, May 15, 1951, pp. 520-521.

Landauer, Rolf: Maximum Rate of Wave Function AmplitudeChange. Phys. Rev., vol. 82, no. 4, May 15, 1951, p. 549.

Landauer, Rolf: Reflections in One-Dimensional WaveMechanics. Phys. Rev., VOL82, no, 1, Apr. 1, 19!51,pp. S0-8S.

McLellan, Charles H,: Exploratory Wind-Tunnel Investigationof Wings and Bodies at M=6.9. Preprint 822, Inst. Aero.SCL, 1951.

Martin, J, C.: Retarded Potentials of Supersonic Flow. Quart.AppL Math., VOLVIII, no. 4, Jan. 1951, pp. 858-S64.

Nagey, Tibor F.: Four Turboprop Conflguratkms. . . . HowThey C.%mpare. SAE Jour., vol. 59, no. 8, M&m.1031, PP. 22-23.

Nelce, Stanford E., and IIhret, Dorrls M.: Similarity Laws forS1ender Bodies of Revolution in Hypereontc Flows. Preprint821, Inst. Aero. SCL, 1951.

Rodert, Lewis A.: progress in Fire Prevention Following Crash.Preprint 265, Inst. Aero. SCL, 1950.

Rogallo, Francis MeIvin: Lateral ControI of PerYunaI Aircraftat High Lift Ceef3iclente. Aero. Eng. Rev., vol. % no. S, Aug.1950, pp. 18-22.

RogaIlo, Francis M.; Lowry, John &; and FLscheI, Jack:Lateral-ControI Devices Suitable for tTse with Full-Spnn Ftape.Jour. Aero. Sri., VOL17, no. 10, Oct. 19S0, PD.6204S8, 652.

Runyan, H. L.; Cunningham, H. J.”; and ‘il’atkins, C. El.: Theo-retical Investigation of Several Types of. Slngle-Degree-of-Freedom Flutter. Preprint S25, Inst. Aero. ScL, 1031.

Schwed, P.: Surface Dlffuslon in Sinterlng of Spheres onPlanes. Jour. Metals, vol. 191, no. 8, Mar. 1051, pp. 245-24&

Siraonj Dorothy Martin: A Comparison of Quenching Distanceand Inflammability Limit Data for Propane Ah’ Flames. Jour.AppL Phys., vol. 22, no, 1, Jan. 1951, p. 10S.

Simon, Dorothy Martin: Flame Propagation. 111. !l?beoretfcatConsideration of the Burntug Velocities of Hydrocarbon&Jour. Am, Ohem. Sot., YOL78, no. 1, Jan. 1051, Pp. 422+%

Spakowski, A, E.; Evans, Albert; and Hibbard, R. R.: Determi-nation of Aromatics and Olefins in Wide Boiling PetroleumFractions. Analytical Chem., vol. 22, no. 11, Nov. 19W, pp.1416-1422,

Spreiter, John R., and Sacks, Alvin H.: The Rolltng Up of theTrailing Vortex Sheet and Its Effect on the Downwaeh behindWings. Jour. Aero. SCL, VO1.18, no. 1, Jan. 1051, Dp. 21-S%72.

Stanitz, John D.: Analysls of the Exhaust Process in Four-Stroke Reciprocating Engines. Trans. A. S. M. E., vol. 78,no. S, Apr. 1951, pp. 819-829.

Stevens, Victor I.: Hypersonic Research Facilitke at the AmesAeronautical Laboratory. Jour. AppL Physim, vol. 21, no. 11,Nov. 1950, pp. l15&l155.

Wu, Chung H.: A General Theory of Three-Dimensional I?1owwith Subsonic and Supersonic VeIoctty in Turbomachines Hav-ing Arbitrary Hub and Casing Shapes. Paper 5&A-79,A. S. M. E., 1950,

Wu, Chung-Hua, and Brown, Curtis A.: A Theory of the Directand Inverse Problems of Compressible Flow Puet Cascade ofArbitrary AirfoW Preprtnt S26, Inst. Aero. Sci., 1051.

Yntema, Robert T.: An Impulse-Momentum Bfethocl for Calculat.ing Landing Gear Impact Conditions in Unsymmetrical Land-tngs. Preprint 824, Inst. Aero. Sci., 1951.”

Part II—COMMITTEE ORGAiVZZATION AhTl) MEMBERSHIP—

The act of Congress approved March 3, 1915, e&ab-lishing the National Advisory Committee for Aero-nautics, m amended (U. S. Code! Supplement IV, title50, sec. 151), provides that the Committee .shaUconsistof 17 members appointed by the President, and shallinclude “two representatives of the Department of theAir Force; two representatives of the Department ofthe Navy, from the officein charge of nawil aeronauti=;two representatives of the Citil Aeronautics Author-ity; one repre.smtatke of the Smithsonian Institution;one representati~e of the United States ‘iVeather Bu-rew: one representative of the National Bm-eau ofStandards; the Chairman of the Research and Develop-ment Board of the h’ational MiLitary Establishment;and not more than seven other members selected frompersons acquainted with the needs of aeronautical sci-ence?either civil or miIitary, or skied in aeronauticalengineering or its allied scienc~” These latter sevenmembers serve for terms of 5 years. The representa-tives of the Government or=~nizations serve for indefi-nite perioik. All members serve as such without com-pensdion.

Hon. Donald ~. X-pop, Chairman of the Civil Aero-nautics Board: was appointed by President- Truman amember of the National Advisory Committee for &ro-mmtics under date of April 24, 1951, succeedi~u Hon.Delos R. Rentzel, who resigned from the Committeebecause of his appointment as Under Secretary of Com-merce for Transportation.

In accordance -with law, Hon. Walter G. ~tmanwas appointed a member of the Committee August 9,1951, following his appointment tts Chairman of theResearch and Development. Board. Professor Tilit-man succeeded Hon. ‘iVillimn ~ebster: who resignedfrom the Committee in July, concurrently with hisresi~atiou as Chairman of the RD13.

Becnuse of his retirement from the United StatesAir Force, the membership of Maj. Gem Gordon P.SaviIIe on the Committee was terminated July 31,1951.Genernl Snville was serving as Deputy Chief of St+Development, in the Air Force. Amother terminationof membership resulted from the resignation of Dr.Edviard U. Condon as Director of the National Bureauof Sttmdardsyeffectire September 30, 1951. Successorsto General Saril.le and Dr. Condon on the Committeehave not been appointed.

In accordance with the regulations governing theorganization of the Committee as approved by thePreeiclent. the Chairman anclVice Chairman nre electecl

annually, as are aIso the Chairman and Vice Chairmanof the Executive Committee.

On October 12, 1951, Dr. Jerome C. Hunsaker wasreekcted Chairman of the h~AC!Aand of the ExeoutiveCommittee, and Dr. Alexander TVetmoreand Dr. Fran-cis V. ReicheIderfer -werereelected Vice Chairman ofthe NACA and ?’ice Chairman of the Executive Com-mittee, respectively.

COMMITTEE ON AERODYN~CS

Dr. Theodore P. Wright, Cornell University, Chairman.@apt. Walter S. Dieh4 U. S. N. (Ret.), Vice OhafrmamDr. Albert E. Lombard, Jr,, Odice, Directorate of Research and

Developmen& U. S. & Force.COLJack L Gibbs, I?. S. A. F., Air Mat&iel Command.Mr. F. & Londen, Bnreau of Aeronautics, Department of the

A-ary.Capt. M. R. KeUey, U. S. N. (Ret.), Bureau of Ordnance.Brig. C?=. Leslie E. Shnon, U. S. A., Chief, Ordnance Research

and Development Di*ion.Mr. Harold D. Hoekstra, CiPII Aeronautics Administration.Dr. Hugh L. Dryden (SX oftlcio).Mr. FI(J@ L. ‘lTmmpson. XACA Langle~ Aeronautical Labora-

tory.Mr. RusseIl (3. Roldneon, NACA bee Aeronautical Labora-

tory.Prof. Jesse W. Beams, UniveraI@ of Wr@da.Mr. Edward J. Horkey, Xorth AmerScan A~fatio& Inc.Mr. CIm-ence L. Johnson, Lockheed Aircraft Corp.Mr. John G. Lee, United AW?raft Corp.Mr. Grover Loening.Dr. Clark B. ~ CaUfornia ~titute of Technology.Dr. W. BaiIey OsvnU& Dough Aircraft Co., Inc.Mr. George S. Schairer, Boeing Airplane Co.Prof. E. S. Tr@or, 31aseachusetts Institute of TeclmoIogy.Mr. Robert J. Woods. Bell Aircraft Corp.

Mr. MIIton B. &nes, Jrq secretary

S&committee on Fluid Mechanics

Dr. C1nrli B. Mtllikaq CalLfornta Institute of Technology, Ohair-man.

Dr. Frank L. Wattendorf. DCS/~e~elopment, Hq.r U. S. AirForce.

Mr. L. S. Wasserma& Wrf@t Air Derelopment Center.Capt. W. S. Diehl, U. S. N. (Ret.).Dr. E. ?3romberg, Otlice of NaraI Research, Department of the

Nllw.Dr. Raymond J. Seeger, ISawil Ordnance Laboratory.Mr. Joseph Sternberg, BaUietfc Research MbOratories, Aber-

deen Proving Ground.Dr. (1. B. Schubauer, National Bureau of Standards.Dr. Carl Kaplan, NAOA Langley Aeronautical Lalwratory.Mr. John Stack, NAC!ALangley Aeronautical Laboratory.Mr. Robert T. Jones, XACA Ames Aeronautical Laboratory..Mr. IVrtlter G. Wncentf, XACA Ames Aeronautical Laboratory.

——.

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47

48 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Dr. John C. Evvard, NACA Lewfa Flight Propulsion Laboratory.Dr. William BolIay, North .huerkan Aviation, Inc.Dr. Francis H. Clauser, The Johns Hopkins University.Prof. Howard W. Emmons, Harvard University.Dr. Hans W. Liepmann, C!allfornfa Institute of Technology.Dr. C. C, Lin, Massachusetts Institute of Technology.Dr. William R. Sears, Cornell University.

Mr. E. O. Pearson, Jr., Secretary

Subcommittee on High-Speed Aerodynamics

Mr. John G. Lee, United Aircraft Corp., Chairman.CO1.Robert M. Wray, U. S. A. F,, Wright Afr Development Center.Mr. H. L. Anderson, Wright Afr Development Center.Oommander Sydney S. Sherby, U. S. N., Bureau of Aeronautics.Dr. George L Nine, Naval Ordnance Laboratory.Mr. U. L Poor, III, Ballfstic Research Laboratories, Aberdeen

Proving Ground.Mr. Robert R. Gflruth, NACA Langley Aeronautical Laboratory.Mr. John Stack, NACA Langley Aeronautical Laboratory.Mr. H. Julian Allen, NAC?AAmes Aeronautical Laboratory.Mr, Abe SiIverstefn, NACA Lewis Flight propulsion Laboratory.Mr. Irving L. Aehkenas, Northrop Afrcraft, Inc. JMr. Benedict Cohn, Boeing Airplane Co.Mr. David S. Lewis, Jr., McDonnelI Aircraft Corp.Mr. Harold Luakfn, Douglas Aircraft Co., Inc.Prof. John R. Markham, Massachusetts Institute of Technology.Mr. C. E. Pappas, Republic Aviation Corp.Dr. Allen E. PucketL Hughes Aircraft Co.Mr. William C. School&ld, United Aircraft Corp.Mr. H. A. Storm% Jr., North American Avfatfon, Inc. ,

Mr. R. H. IVidmer, Consolidated Vultee Aircraft Corp.

Mr. Edward C. Polhamus, Secretary

Subcommittee on Stability and Control

Capt. Walter S. Diehl, U. S. N. (Ret,), Chairman.Mr. Melvin Shorr, Wright Afr Development Center.Mr. GeraldG. Kayten,Bnreauof Aeronautics,Departmentof

tie Navy.Mr.PhfllppeW. Newton,IJ.S. ArmyOrdanceCorm.Mr.JohnA.Carran,CIV1lAeronauticsAdmfnfstration.Mr.ThomasA. Harris,~AOALangleyAeronauticalLaboratory.Mr.HarryJ. Goett,NACAAmesAeronautfcalLaboratory.Mr.GeorgeS.Graff,McDonnellAircraftCkJrp.Mr.HerbertHarr@ Jr.,SperryGyroscopeCo.,Inc.Mr.StuartA. Krfeger,~orthro~Aircraft, Inc.Mr.W. F. MmMen,Jr.,CorneIlResearchFoundation,Inc.Mr.DaleD. Myers,NorthAmericanAviation,Inc.Prof.CourtlandD. Perklm,PrincetonUnfversltY.Prof.RobertC. Seamans,Jr.,MassaclmsettsInstituteof Tech-

nology.Mr.RalphH, Shick,ConsolidatedVulteeAfrcraftCorp.Mr.CharlesTllgner,Jr.,GrummanAircraftEn@neerIngCorp.Prof. Fred E. VVeic~AgrIctituralanrlMechanicalCollegeof

Texas.Mr.JackD. Brewer,Secretary

Subcommittee on Internal Flow

Mr. Philip A. Colmm Lockheed Aircraft Corp., Chairman.Mr. Joseph Flatt, Wright Afr Development Center.Capt. Walter Haaser, U. S. A. F., Wright Air DoveIopment

Center.Commander R. L. Dnncan, U. S. N., Otllce of Navnl Research.

Mr. Palmer R. Wood,Bureauof Aeronautics,DepartmentoftheNavy.

Mr.C. L. Zakhartchenko,NationalBureauof Standarcls.Mr. John V. Becker,NACALangleyAeronauticalLaboratory.Mr.E. A. Moeaman,NACAAmesAeronauticalLaboratory’.Mr.DeMarquisD. Wyatt,NACALewfsFllgbtPropulsionLab-

oratory.Mr.J. S.Alford,GeneralElectricCo.Mr.LeoA. Geyer,GrummanAircraftEtngfneerlngCorp.Mr.HenryH. Hoadley,UrdtedAfrcraftCorp.Dr. WilIiamJ. O’Donnell,RepublicAviationCorp.Mr.OttoP. Prachar,GeneralMotorsCorp.Mr.AscherH. Shapiro,MassachusettsInstftuteof !Wchnology.Mr.MauriceA. Sulkin,NorthAmericanAviation,Inc.

Mr.EdwardC. Polhamus,Secretary.

Subcommittee on Propellers for Aircraft

Mr. Thomas B. Rhinee, Hamflton Standard Division, United Air-craft Corp., Chulrman.

Mr. Anthony F. Dernbach, Wright Air Development Center.Mr. Danfel A. Dickey, Wright Air Development Center.Mr. Ivan H. Driggs, Bureau of Aeronautics, Department of the

Navy.Mr. John C. Morse, Civil Aeronautics AdminietratiomMr. Eugene C. DraIey, NACA Langley Aeronautical Laboratory.Mr. Robert M. Crane, NACA Ames Aeronautical Laboratory.Mr. George W. Brady, Curtfae Wright Corp.Mr. Frank W. Crddwell, United Aircraft Corp.Mr. Wilfred W. Davies, United Afr Lines, Inc.Mr. Ralph R. I.aMotte, General Motors Corp.Mr. E. B. Mmke, Jr., Consolklated Vultee Aircraft Corp.Mr. Robert B. Smith, Douglas Afrcraft Co.. Inc.

Mr. Ralph W. May, Secretary.

Subcommittee on Seaplanes

Mr. Grover Loening, Chairman.Mr. JoseplI A. Ellis, Wright Afr Development Oenter.Mr. J. H. Herald, Wright Alr Development Center.Mr. Charles J. Daniels, Bureau of Aeronaut lcs, Department of

the Navy.Mr. Ii’.W. S. Lock% Jr., Bureau of Aeronauti~ Department of

the Navy.Mr. Charlfe C. Garrison, 0t3fce of Naval Research, Department

of the Navy.Commander W. C. Fortune, U. S. N., Davh.1 Tftylor Model Basin.Commander John A. Ferguson, U. S. N., Naval Air Test Center,

Pat uxent.Capt. Donald B. MacD1armId, U. S. C. G., U. S. Coast Guard Alr

StatIon, San Diego.Mr. John B. Parkinson, NACA Langley Aeronautical Labora-

tory.Mr. Robert B. Cotton, All American Airways, Inc.Dr. K. S. M. Davidson, Stevens Institute of Technology.Mr. J. D. Pierson, the Glenn L. Martin Co.Mr. Willlam R. Ryan, Edo Corp.Mr. E. G. Stout, Consolidated Vultee Aircraft Corp.Mr. Henry B. Suydam, Grnmman Aircraft Engineering Corp.

Mr. Ralph W. May, Secretary.

Subcommittee on Helicopters

Mr. Richard H. Prewitt, Prewltt Aircraft Co., Chairman,Mr. Bernard Lfndenbaum, Wright Air Development Center.

REPORT NATIONAL ADVISORY CO~TTEE FOR AERONAUTICS a

lua~t.pad s~mmons,Jr., U. S. A. F., Wr&ht fir DevelopmentCenter. o

Mr. Raymond A. Young, Bureau of Aeronautfc& Department ofthe h-m-y.

Commander Frank A. Erickson, U. S. C. G.r U. S. Naval Air Sta-tion, Patusent.

Lt. COLJack L Marineu F. A., Army F1eld Forces.Mr. Burdell L. Springer, Cfvll Aeronautics Admlrdatration.Mr. R. I%Maloyr Civil Aeronautics Administration,Mr. Richard C. DingeIde@ NACA Langiey Aeronautical Labo-

ratory.Mr. F. B. Gnstafson, NACA Langley Aeronautical Laboratory.Mr. M[chael E. GlnhareK, Sikorsky Alrc- United Aircraft

Corp.Mr. Bartram Keiley, BeIi Aircraft Corp.Mr. Rene H. Miller, Massachuset@” Institute of Technology.Mr. Robert R. Osbo~ McDonnell Aircraft Corp.Mr. F. N. PIase&~ Phweckl Helk?opter Corp.Mr. N. M. Stefano, Hnghea Aircraft Co. .

?&. LesI[e E. Schneiter, Secretary.

Special !%bco-ttee on the L’pper Atmosphere

Dr. Harry TVexler, U. S. Weather Bureau, C’_hairman.CO1.Benjamin G. Holzman, U. S. L IT., Offtcer Deputy Chtef of

Sta& for Mat&iel, Department of the Air Forc&Dr. Sverre Petteresen, Air Weather Service, U. S. Air Force.Capt. Waiter S. Dle~ C!.S. N. (Ret.).Dr. Homer E IfeweIl, Jr.r Naval Research Laboratory.Dr. 0. R. Wulf, Caltfortda Institute of Technology.Dr. W. G. Brombacher, National Bureau of Standards.Mr. Vi’iillam J. O’Suiiivan, NACA Langley Aeronauttcai Labo-

ratory.Dr. Carl W. Gartiein, CorneIl University.Dr. B. Gntenberg, California Institute of TecimoIogy.Dr. Harvey Hail, OfEce of h-aval &search, Department of the

Navy.Prof. Bernhard Haurwi@ New York University.Dr. Jowph KapIan, University of California.Dr. TV.W. Keiiogg, The Rand Corp.Dr. Zdenek KopaI, Mazwwhnsetta Instttnte of Technology.Dr. C. L. PekerIs, the Instltnte for Advanced Study.Dr. J. A. Van AIIe& The Johns Hopkins Unhrsfty.Dr. Harry W. W’ells, Carnegie Institution of M%shmgton.Dr. Fred L. ‘Whipple, Harvard Urd~ersity.

Mr. I&e EL Schnelter, Secretary.

COMIWITEK ON POWER PLANTS FOR AIR~

Mr. Ronald M. Hazeu AIUson Division, General Motors Oorp.,Chairman.

Prof. E. S. Taylor, Massachusetts Institute of Technology,Vice Chairman.

COL Norman C. Appold, U. S. A. F., Clbie~ Power PiantLaboratory.

Cal. Paul F. N“ay,U. S. A. F., Chief, Propulsion Branch, AircraftDhision.

Capt. ?3.M. C!ondra, Jr., U. S. N., Bnreau of Aeronautics.Mr. Stephen Rolle, Civil Aeronauth?s AdmlnIatraffon.Dr. Hugh L. Dryden (SX odicfo).Mr. Abe SIIrerstei& NAOA Lewis Flight Propulslon Laboratory.Mr. Frank W. Davis, Canaoiidated Vrdtee Afrcraft Corp.Dr. LOUISG. D- CaUfornfa Institute of Technology.Mr. ‘i’i’illiamM. Holaday, Socony Vacnum Oli Coy Inc.Mr. R. P. Kroon, Westinghouse Electric Corp.Mr. V7i111amC. Lawrence, Amerfcan Airllnes, Inc.

Mr. Wllton G. Lnndquiat, Wrtght Aeronaut&al Cam, D1viskmof Curt isa-lVrfght Corp.

Mr. wright L ParkLns, Pratt and Whitney Aircraft DIvlslon,Crdted Aircrtit Carp.

Mr. Gearge S. Schafrer, Boeing Airplane Co.Mr. Raymond W. Young, Reaction Motors, hm.

Mr. T’iliifam H. TWodward, Secretary.

.%hcommittee on Aircraft Fuels

Dr. J. Bennett Hlil, Sun Oli Co., Chairman.Lt. COL .J. H. Lee, U. S. L F. Propulsion Branch, ALrcraft

Dhkion.M4. ~ W. SIEWesoLU. S. A. F., WrightAir Derelopmeut

Oenter.Comdr.Robel~F. Wa~or@ u. S.N. Burenuof Aeronautics.Mr.RaIphS. White,CIVRAeronauticsMrnfnistraffon.Dr.L.C. Gibbons,NACALewisFl@t PropulsionLaboratory.Dr.D. P.Bmnard,Standard O!l Co. of Indiana.Mr. A. J. Blackmood, Standard OIi DewIopment Co.Mr. J. L. Coole~, California Research Corp.Mr. S. D. Heron, Ethyl Corp.Mr. W. 3L HoIaday, Socony-Vacuum Oii Co., Inc.Mr. C. R. JOIIIISOLSheII OU 00.Mr. Melvfn H. Young, Wrfght Aeronautical Corp., Divtsion of

Curtiss-’iVright Corp.Dr. W. E. Kuhn, The Texas Co. —.-—Mr. O. E. Rodgers, Aviation Gas Turbine Dhtslon, Westinghouse

Etectric Corp.Mr. KarIe & Ryder, Pratt and V7hNney Aircraft D1vieiou

United Aircraft Corp.Mr. HaroId M. Trhuble, Phillips Pt?trolenra Co. —.

Mr. Henry E. Aiquist, Secretary.

.%beonunittee on Cornhustion

Dr. Bernard Lewis, Bureau of MLnes, C!hafrman,Dr. D. G. Smnaras, Wright & Development Center.Mr. Garrett L. Wander, Wright Air Development Force.Mr. N. N. Tilley, Bureau of Aeronautics, Deparbnent of the

h’avy.Mr. Edward H. Seymour, OtEce of Navai Research, Department

of the Navy.Dr. Ernest F. Fioc?+ A-ational Bureart of Standards.Dr. Waiter T. Oiscq NACA Iavie ??lfght Propnision Laboratory.Mr. Edmund D. Brown, Pratt and Whitney Aircraft Division,

United Mrcrnft Corp.Dr. Alfred G. Cattaneo, Sheii Dereiopment Co.Prof. Newman A- Hall, CnMersity of Minnesota.Dr. John P. Long’iveR, Standard OiI Development CO.Mr. A J. Nera& General Ekctric Co.Dr. Robert N. Pease, Prtnceton lhiveralty.MY.Edwin P. Wal@ Westinghouse Electric Corp.Prof. G1enn C. Vi’fUIams,Massachnaetts Institute of Technology.I)r. Kurt Ti’ohl, University of Delaware

Mr. Henry E. Alquist, Secretary.

%hcornmittee on Lukication and Wear

Mr. ELM. PhiiLim, General Ek!CtI’iCb., OWdrIUan.Mr. J. Josteiier, ‘Wright Air Development Center.Mr. Robert C. Sheard, Wright AIr DereIopment Center.Mr. Charles C. SingIeterry, Bunmn of Aeronautics, Department

of the Navy.Dr. V$lliiarn Zisman, h-avaI Research Laboratory, Department of

the Navy.

50 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Mr. Edmond E. Bisson, NACIALewis E’light Propulsion ~bora- Subcommittee on Heat-Resisting Materialstory.

Mr. Richard W. Blair, Wright Aeronautical Corp., Division ofMr. &’thur W, F. Green, General Motors Corp., Chairman.

Curtlss-Wright Corp.Mr. J. B. Johnson, Wright Air Development Center.Mr. Nathan El. Promisel. Bureau of Aeronautics, Department of

Dr. John T. Burwell, Jr., Horizons, Inc. the Navy.Dr. Merrell R. Fenake, Pennsylvania State College.Mr. Daniel Gurney, Marlin-Rockwell Corp.

Mr. Benjarotn Pinkel, NACA Lewts Fii@t Propulsiontory.

Dr, Robert G, Larsen, ShelI Development C%.Mr. C. J. McDowall, AIlison Division, General Motors Corp.

Mr. W. L. Badger, GemeraJ Electric Co.

Mr. Joseph PalsuIich, Olevelaud Graphtte Bronze Co.Mr. Howard C. Cross, Battelle Memorial Institute.

Mr. Earle A, Ryder, Pratt and Whitney Aircraft Division, UnitedMr. P. G. DeHuff, Jr., W’esttnghouee Electric Corp.Mr. Russell Franks, Union Carbide & Carbon ~rp.

Labora-

Aircraft Corp.Mr. 0. H. Stockdale, Westinghouse Electric Corp.

Mr. Herbert J. French, International Nickel CO.Prof. Nicholas J. Grant, Massachusetts Institute of Technology.

Dr. Haakon Styr!, SKF Industries, Inc.Mr. Arthur F. Underwood, General Motors Corp.Mr. W. Andrew Wright, Sun Oil CO.

Mr. William H. Woodward, Secretary.

Subcommittee on Engine Performance and Operation

Mr. Arnold H. Redding, Westinghouse EIectric Corp., Chairman.Mr. Opie Chenoweth, Wright Air Development Center.Mr. (3. G. Sorgen, Bureau of Aeronautics, Department of the

Navy.?&’. Bruce T. Lundin, NACA Lewts Flight Propulsion Lal)ora-

tory.Dr. John L. Barnes, North American Aviation, Inc.Profl Gordon S, Brown, Mqeeachueetts Institute of Technology,Mr. Dimttrius Gerdan, Allison Division, General Motors Cap.Mr. John Karrmik, Grumman Ah-craft Engineering Corp.Dr. Roy E. Marquard& Marquardt Aircraft ClotDr. WiUtam J. O’Donnell, Republic Aviation CWp.Mr. Erold F. Pierce, Wrtght Aeronautical Corp., Division of

Curtlss-Wright Corp.Mr. Perry W. Pratt, Pratt and Whitney Aircraft Divlslo%

United Aircraft Corp.Mr. El. E. Stoeckly, General Electrlc Co.Mr. Imn Storey, Jr., Lockheed Aircraft Corp.Mr. Lee R. Woodworth, The Rand Corp.

Mr. Richard S. Ceearo, Secretary.

Subcommitteeon Compressors and ‘lhrbiies

Prof. Howard W. Emmons, Harvard University’, Chairman.Mr. Ernest C. Simpson, Wright A1r Develo~ent Center.Mr. Robert W. Pinnee, Bureau of Aeronautics, Department of

the Navy.Commander R. L. Duncan, U, S. N., Oilke of Naval Research,

Department of the Navy.Mr. John R. Erwin, NACA Langlcy Aeronautical Laboratory.Mr. Robert O. BullocQ NACA Lewis Fiight Pro~ulsion Labora-

tory.Mr.KennethCampbell,Wright Aeronautical Corp., Divtaion of

Curties-Wright Oorp.Mr. Walter Doll, Pratt and Whitney Aircraft Division, United

Aircraft Corp.Mr. Jack 0, Fetters, AIliaon Divhdon, General Motors Oorp.Mr. R. S. Hall, General Electric UO.Dr. Frank ?3. Marble, Calfforrda Institute of Technology.Mr. Charles A. Meyer, Westinghouse Electric Corp.Prof. George F. Wislicenus, The Johns Hopktns University.

31r. Guy N. Unman, Secretary.

Mr. Alvin J. Herzig, Oli”r.uaxMolybdenum Co. of Mtchlgan.Dr. L. H. Milligan, Norton CO.Dr. Gunther Mohling, Allegheny Ludlum Steel Corp.Mr. RudoIf H. Thieleman~ Pratt and Whitney Aircraft Division,

United Aircraft Corp.

Mr. William H. ‘iVoodward, Secretary.

‘Special Subcommittee on Rocket Engines

Dr. Maurice J. Zucrow, Purdue University, Chairman,Mr. C. W. Schnare, Wright Air Development Center.Commander K. C. Childer& Jr., U. S. N., Bureau of Aeronautics,

Department of the Navy.Capt. Levering Smith, U. S. N., Naval Ordnance Test Station,

Inyokern,Mr. Joseph L, Gray, Otlice of the Chief of Ordnnnce, Depart-

ment of the Army.Mr. Paul R. Hill, N’ACALangley Aeronautical Laboratory.Mr. John L. Sloop, NACA Lewis F1lght Propulsion Laboratory.Mr. Richard B. Canright, California Institute of Technology.Mr. R. Bruce Foster, Bell Aircraft Corp.Mr. Stanley L. Gendler, The Rand Corp.Dr. George E. Moor% General Electric Co.Mr. Thomas D. Myers, North American Aviation, Inc.Mr. Jack H. Sheets, Curtiss-Wright Corp.Dr. Robert J. Thompson, J’r., M. W. Kellogg Co.Dr. Paul F. ‘ivinternitz, Reaction Motors, Inc.Mr. David A. Young, Aero.let Engineering Corp.

Mr. Henry E. AlquisG Secretary.

COMMITTEE ON AIRCRAFT CONSTRUCTION

Dr. Arthur E. Raymond, Douglas Aircraf t “Co,,Inc., Chairman..Mr. R. L. Templin, A1uminum Co, of America, Vice Chairman.Mr. E, H. Schwallz, Wright Air Development Center.Capt. Robert S. Hatcher, U. S, N., Bureau of Aeronautics, De-

partment of the Navy.Mr. Albert A, Vollmecke, CIvil Aeronautics Administration.Dr. Hugh L. Dryden (ex ornc~o).Dr. Henry J. E. Reid, NACA Langley Aeronautical Laboratory.Mr. Carlton Bioletti, NACA Ames Aeronautical Laboratory.Prof. Raymond L. Bispllnghoff, Massachusetts Inst [tnte of Tech-

nology.Prof. Emerson W. Conlon, University of Michigan,Dr. C, C. Furnas, ClmnelI Aeronautical Laboratory, Inc.Dr. Alexander A. Kartveli, It@public Aviation Corp.Mr. W. C. Mentzer, United Alr Lines, Inc.Mr. George Snyder, Boeing Alrpiane Co.Mr. Luther P. Spalding, North American Aviation, Inc.Mr. CharIes R. S’trang, Douglas Aircraft Co., Inc.

Mr. Franklyn IV. PhilUps, Secretary.

REPORT NATIONAL ADVISORY COMEUTTEE FOR AERONAUTICS 51

Subcommittee on Aircraft Structures

Mr. C!lmrles R. Strang, DougLas Ah’craft Co., Inc., Chairman.Mr. J. W. Frme~ Wright Air De~eIopment Center.Mr, Joseph Kelley, Jr., Wright Air Development Center.Canrnander L S. Ohambers, U. S. X., Bureau of Aeronautics,

Department of the Navy.Nr. RaIph L Creel, Bureau of Aeronautics, Bureau of AeM-

nautlcs, Department of the Navy.Mr. VW1iam T. Shtder, Civil Aeronautics AdrainiatratiomMr. Samuel Levy, Nattonal Bureau of Standards.Dr. Eugene E. Lundqufss. NA2A Langley AeronriuticaI Labora-

tory.Prof. W. H. GaIe. Massachusetts Institute of Technology.Mr. Ira G. Hedricl& Grnmrnan ~rcrsft Engineering Corp.Dr. A-icholas J. Hoff, PoIytechnlc Institute of Brooklyn.Mr. Jerome F. ilIcBrearty, Lockheed Aircraft Corp.Mr. Francla MeVay, RepnbIic Aviation Corp.Mr. John H. Meyer, McDonnell Aircraft Corp.Prof. Ernest E. Sechler, Cdlfornia Institute of Technology.Mr. R. L. TempMn, Aluminum Cm of herica.

Mr. 31eltin G. Rosche, Secretary.

Subcommittee on Aircrnft Loads

Mr. George Snyder, Boetng MrpIane Co., Chairman.Mr. Joseph H. Harrh@o& Wright Afr Development Center.Mr. Edward J. Lnnney, Wrfght. Air De~eIopment Center.Commander Donald J. Ehudy, U. S. N., Bureau of Aeronautics,

Department of the X-avy.Mr. John P. Wamser, Bureau of Aeronautics. Department of the

Navy.Mr. BnrdelI L. Springer, Cirfl Aeronautics Admlnistrat!on.Mr. Philip Done&, XACA Langley Aeronautical hborator~.Mr. Manley J. Hoodr NACA Ames Aeronautical Laboratory.Mr. Albert Epsteiq Republic Aviation Corp.Mr. F. D. Jewett, The Glenn L. Martin Co.Mr. Jerome F. McBremty, Lockheed ,&rxsft Corp.Mr. Alfred L SibiIa, Chance Vought Aircra@ untted

Corp.2Jr. K. E. Van Every, Douglas Atrcraft Co., Inc.

Mr. R. Fabian Goranson, SecretaIT.

Subcommittee on Vibration and Flutter

Aircraft

Prof. Raymond L BLspIingboff, Massachusetts Institute of Tech-nology, Chairman.

Mr. Howard A. Magrath, Wright Afr Development Center.Mr. L. S. Wasserman, Wright Air Development Center.Capt. ‘Waiter S. Dlehl, U. S. N. (Ret.).Mr. James E. Walsh, Bureauof Aeronautics,Departmentof the

Nav.Mr.RobertRosenbaum,CfvflAeronauticsAdminWratlon.Mr.I. E. Garrlck.NAC4LangleyAeronauticalLaboratory.Mr. AlbertErickson,NACAAmesAeronauticalLaboratory.Mr. Samuel S. Manson, NACA Lewis Flight Propulsion Labora-

CowDr. J’iT1liamE. Co= Northrop Aircraft, Inc.Dr. J. M. FrnnJrlan& Chance Yonght Aircra~ United AircraftCiorp.Mr. Martin GoIan& XUdwsst Research In$&ute.Mr. E B. Khmaman, Boeing Atrplane Co.Mr. Raymond A. Pepping, McDonnelI .Mrcmft C@P.

Mr. Har~ey H. Brown, Secretary.

Subcommitteeon .Aireraft Structural Materialn

Mr. Edgar H. Dix, Jr., .Mnmtnum Co. of Amerim Chairman.Mr. J. B. Johnso& Wrfght ASr Development Center.Mr. James E SnlIi~an, Bureau of Aeronautic& Department of

the Navy.Dr. Gordon M. Kline, Nattonal Bureau of Standards.Mr. James E. Dougher@, Jr., Civil Aeronautics Administration.Mr. Frank B. BoIte, North American Avfatio& IrIc.Prof. Mtmvcll C4ensamer, Colmnbia Unt-wwaity.lfr. O. W. ikudenslsger, Goodyear *raft COW.Dr. J. C. McDonald, The Dow Chemical Uo.Dr. Robert F. Whl, Carnegie Institute of Technology.m. PauI P. Xtozdey,Lackheed Aircraft Corp.Mr. Dati G. Reid, Chance Vought Aircraft Division, Urdted

Aircraft Corp.Mr. D. H. Ruhnke, RepnbIfc Steel Corp.

Mr. OharIes V. Krebs, secretary.

COMMITTEE OX 0PER41XNG PROBLE.MS

Mr. wfllism Ltttlewoo& AIuerlcan Airlfnes, Inc., CbaMnan.Mr. Charles Frees@ Eastern ti Lfnee, Inc., Vice Chairman.Col. Baskin R. Lawrence, Jr., U. S. A E’., Wright Atr Develop-

ment Center.Cd. J. Francis Taylor, Jr., U. S. A. F., Wright Air Development

Center.Commander A. L. Maccnbbin, U. S. X., Bureau of Aeronautics,

Department of the Navy.314. Gen. ViUItam H. Tunner, U. S. L, HcI., MUitary ASr Trans-

port Service.Dr. F. Vi’.ReicheIderfer, Chief, U. S. Weather Bureau.Mr. George W. Haldernm& Civil Aeronautics Administration.Mr. Donald M. Stuart, Civtl Aeronautics Admfnfatraffon.Dr. Hugh L. Dr@en (ex ot3cfo).Mr. Melvin N. Gongh, NACA Lsngley Aeronautical Laboratory.Mr. Eugene J. Ma.nganiello, NACA Lewis Fi@t PropnlAon

Laboratory.Mr. P. R. Bassett, SWrry Gyroscom Co., Inc., DPdslon of the

Sperry Corp.Mr. M. G. BearG American AIrlfnes, ~c.Mr. John G. Borger, Pan American World Airways, Inc.Mr. Warren T. Dicktnson, Douglas Aircraft Co., Inc.Mr. Roh?rt E. Johnson, Wright Aeronautical Corp., DMsion of

Cnrriss-’Tright COW.Mr. Jerome Lederer.Dr. ROSSA. McE’arIandt Harvard School of Public Health.Mr. W. C. 3fentzer, United -Mr Line9, Inc.

Dr. T. L. K. SnmlL Secretary.

Subcommittee on Meteorological ProbIernc

Dr. F. W. Rekhelderfer, U. S. Weather Bureau, ChairmrmBrig. Gem W. O. Senter, U. S. A. F., Air ‘Weather Service.Maj. Frederic. 0. E. Oder, U. S.& F., Air Force Cambridge Re-

search Center.C@. R. O. Minter, U. S. N. Naval Serological Sermce.Dr. Ross Gunn, U. S. Weather Bureau.Mr. DeIbert M. LMIe, U. S. Weather Bureau.Dr. Harry IVcder, U. S. Weather Bureau.Mr. Robert W. Craig, Citi Aeronautics&lmlnistration.Mr.GeorgeM.French,CMl AeronanttcsBoar&Mr.~~ Press,KACALangler&-rommtl@tLaboratow.Mr.L IrringPinkel,2WCALewfsFlight PropuIstonLaboratory.Dr. HoraceR. Byers,Frdmrsityof Chicago.Mr.Marttn B. OahiL Northwest Alrlhs, Inc.

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52 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Mr. Ailan 0, Clark, Pan Ameriean World Airways, Inc.Mr. Joseph J. Qeorg~Eastern Air Lines, Inc.Prof. H. U. Houghton, Massachusetts Institute of Technology.Dean Athelstan F. Spilhaus, University of Minnesota.Mr. Frank O. IVhlte, Air Transport Association of America.Dr. El. J. Workman, New Mexico Institute of Mining end Tech-

nology.Mr. Donald B. Talmage, Secretary.

Subcommittee on Icing ProbIems

Mr. Arthur A. Brown, Pratt and Whitney Aircraft, United Air-craft Corp.

Mr. James ill. DeRemer, Development, U. S. Air Force.Mr. Duane M. Patterson, Wright Air Development Center,Mr. Edward C, Y. Inn, Air Force Cambridge Research Center.Mr. Parker M. Bartlett, Bureau of Aeronauti~ Department of

the Navy.Mr. Harcourt C. Sontag, Bureau of Aeronaut iw, Department of

the Navy.Mr. B. C. Haynes, U. S. Weather Bureau.Mr. Stephen RoIle, Civil Aeronautics Administration.Mr. I. Irving Pinkel, NACA Lewis Fllght Propulsion Laboratory.Mr. DonO. Benson, Northwest Airlines, Inc.Mr. F. L. Boeke, N’orth American Aviation, Inc.Dr. WalIace E. Howell, Mount Washington Observatory.Mr. Victor Hudemq Consolidated Vultee Aircraft Oorp.Mr. David A. North, American Airlines, Inc.Mr. W. W. Reaser, Douglas Aircraft Ch., Inc.Dr. Vincent J. Schaefer, General Electric Co.

Mr. Boyd C. Myers, II, Secretary.

Mr. Frederick A. Wright, Wright Air Development Center.Maj. Charles H. McOonnell, U. S. A. l?., Technical Inspection and

Flight Safety Research.Mr. Arthur V. Stamm, Bureau of Aeronautics, Department of

the Navy.Mr. David L, Posner, Civil Aeronautics Administration.

Mr. Harvey L. Hansberry, Civil Aeronautics Administration.Mr. Hugh B. Freeman, CiviI Aeronautics Board.Mr. A. C. Hutton, National Bureau of Standards.

Mr. Lewis A. Rodert, NACA Lewis Flight Propulsion Labora-tory.

Mr. E. M. Barber, The Texas Co.Mr. Allen W. Dallas, Air Transport Association of America.Mr. Harold E. Hoiwn, American AirIines, Inc.Mr. C. R. Johnson, Shell Oil Co.Mr. Gaylord W. Newton, ARO, Inc.Mr. Ivar L. Shogran, Douglas Aircraft Co., Inc.Mr. Wiliiam I. StiegIitz, Republic Aviation Corp.Mr. CIem G. Trimbach, Corneil Aeronautical Lnborators, Inc.

Mr. Richard S. Cesaro, Secretary.

INDUSTRY CONSULTING COMMITTEE

Mr. Dwane L. Wallace, Cessna Aircraft Co., Chairman,Mr. William N. Allen, Boeing Afrphme Co., Vice Chairman.Dr. Lynn L. BolIinger, HeIlo Aircraft Corp.Mr. Ralph S. Damon, Tzans World Airlines, Inc.Mr. Robert El. Gross, Locidmed Aircrafk Corp.Mr. Roy T. HurIey, Curtiss-Wright Corp.

Subcommittee on Aircraft Fire PreventionMr. C. W. LaPlerrq General Electric Co.

Mr. Raymond D. Kelly, United Air Lin~ Inc., ChatrmamMr. Mundy I. Peale, Republic Aviation Corp.

Capt. Howard A. Klein, U. S. A. F., Wright Air DevelopmentMr. Earl F. Sikk, Slick Airways, Inc.

Center. Dr. T, L. K. Smnll, Secretary,

Part HI-FINANCIAL REPORT

Approprfatkms for the @Ml Uem’ 1961.—Funds and contractautiority in the foIlowing amounts were appropriated for theCommittee for the fiscal year 1951 in the GeneraI AppropriationAct, 195L approved September 6, 1950, and the Second Supple-mental Appropriation Acq 1931, approved January 6, l%il:

8ah’ie9 and uses_-—.-_—-_.__ —__ $45,750, OWConstruction and equipment of laboratory facHities:

Fnnds to continue tbancing of fiscal year 1949program:

Langley AeronautlcaI Labora-tory ----- $6,000,000

Lewis FLight Propulsion Iab-orato~---.-—-----.—---- ~ 000,000

10,000,000Funds to continue tlnancing of tiscal

year 1950 program:Langley Aeronautical Labora-

tory ---——--— ----------Piiotlesw Aircraft Research

station---- ————-Lewls Flight Propukion Lab-

oratory-__-_-_____——

$2, 77L 988

47s, o12

L750,0005,000,000

Funds to start financing of tiscaIyear 1931 program:

Langley Aeronautical Labora-tory—-—--—--—---—--- $200,000

Ames Aeronautical Labora-tory— _____ 300, COO

Lewis Flight Propulsion Lab-tory-___-___-—_—— ~ 81& 000

~ 318,000

Total appropriated funds, tiscd year1931 ----___—— $63, C%.s,Ooo

Oontract authority for remaining obligations neces-sary to compIete flsc-d year 1931 program:

Langley Aeronautical Laboratory ----------- $2,300,000ties Aeronautical Laboratory__——------ s, 700,000

TotaI contract authority, flscal year IiMl-- $11,000,000

Obligations incurred against the flscd year 1951 appropriatedfunds and contract authority are Ilsted below, together withthe unobligated balances remaining on August 81, 1931. Thei3.gnres shown for salaries and expenses include the costs forpersonaI aemlces, tra-ie~ transportation, communication, rItiWysemi- printing and reproductio~ contractnai sertices, SUPplies and equipment.

Salaries and expenses:h“AOA Headquarters___ $L 081, 8i2Langley Aeronautical Laboratory _________ 17, (BL 974Pilotless Aircraft Research Station ----------- s03, !304

SaIaries and ~nses-OontinuedHi@-SPeed Flight Research Statto~_______ $919.281.hnes Aeronautical Laboratory—————— 7,535,818Wastern Coordination Of&e______—-—____ @ 485Lewis FIight Pro@skm Lalxmatory __________ 16,416,186Wright-Patterson Coordination OtEce_________ 10,424Research contra~ncational institntions_— 779,649Services performed by Nationrd Bureau of

Standards and Forest products Laboratory— 209,501Unobligated bahnce_____________ _ 343, &

Total appropriated funds, salaries and ~-penses — —— — 45,750, Oocl

Construction and equipment of laboratory facilities:Funds to continue fhancing of flscd year 1W9

program:LangIey Aeronautical Labora-

tory --------------——---— $5, 63& 400Lewis Flight ProprMon Lab-

oratory _-——__ 8,939,508Unobligated balance____— 1* 092

10,000,000Funds to continue financing of fiscal year 1933

program:Langley Aeronautimi Labora-

tory —-_——_——_ $2,753,533Piloffess Aircraft Research Sta-

tion -_ —________________ 478,663Lewis Flight Propulsion Lab-

oratory _—______ --- L 70s, 099Unobligated balance_____— W 483

5,000,000Funds to start tlnancimg of ftscsl year 1951 pro-

m:Lan@ey Aeronautical Labora-

tory ——————----- $M38,222Ames Aeronautical Laboratory_ 800,000Lewis Fl@ht Propulsion Lab-

Oratory——_ —— ~ 676,706Unobligated balance__--—_ ‘ 19982

2, 81& 000

Total appropriated funds, fiscal year1951 -----———-—-- _$63,06s, ooo

Contract authority for remaining obligation nec-essary to compIete tlscd year 1951 program:

LangIey Aeronautical Laboratory–_-————_ $1, 49i, ‘AlAmes Aeronautical Laboratory _____ 9, In, -786Unobligated balance_---__-__ —__— x6, 32A 470

TotaI contract authority, tial year M55-- $11,000,000

i These unobligated balances remain avauable for obligation in the&al year 1962.

..—

—

—

53

54 REPORT NATIONAL ADVISORY COMMITTEE FOR AERONAUTICS

Appropriation for the Unitarg Win& Tunnel Plan Act.—Funds in the amount of $75,000,000 were appropriated in theDeficiency Appropriation Act, 1950, ap~roved June 29, 1956,for the constmction of wind tunnels authorlsal in the UnitaryWind Tunnel Plan Act of 1949 (Public Law 415, slat Cong.,approved October 27, 1949). These funds are available untilexpended. Allotments and obligations as of June 30, 1951, areas follows:

Obligationm ot June 80,

Ai&tmrnt# 1961

Langley Aeronautical Laboratory---- $1%917,000 $6,440, S60Ames Aeronautical Laboratory ------ 27,227,000 9,904,94-4Lewis Flight Propulsion Laboratory_ 32 S56, 000 9, 90S, 955

Total--__--—--—_ —–—$75, 000,000$26,261,759

Appropriation for the I%KXTl gear 1952.—The major allot-ments of the funds appropriated for the Commlttec for thefiscal year 1952 in the Independent Otflcea Appropriation Act,1952 approved August 31, 1951, are given below:

Salaries and Es~naes ------------------ $49,250, OtMConstruction and equipment of labora-

tory facilities:Funds to complete financing of

fiscal year 1049 program:Langley AeronanticaI Labora-

tory _________ ——-— $372,800

Lewis FUght Propulsion Lab-oratory. ---—_—_____ 550,000

922,800

ObligationConatructlon and equipment of labora- w oj June 80,

tory faciliti-onthmed Allotments 1961Funda to complete tlnancIng of

&al year 1950 program:Langley Aeronautical Labora-

tolT -— ________________ $3,403,524Lewis l?llght Propulsion Lab-

oratory ------------------- 1,600, 000’$4,003, W24

Funds to conttnue fhanclng offiscal year 1951 program:

.Langley Aeronautical Labora-tory --------------------- $1,293,676

Ames Aeronautical Labora-‘“tory --------------------- 4,500,000

5,766, Clit!Fun& to completely finance fiscal

year 1962 program:Langley Aeronautical Labora-

tory_ --_----______-—__Pllotleas Aircraft Ramarch

Station ------------------High-Speed Flight Research

SWtion----— ------------Ames Aeronautical Labora-

tory-----__---_ -_---__ —--Lewis Flight Propulsion Lab-

tory -------------------

$730,000

00,000

4, Ocm,m

1,4s0, 000

350,0006,650,006

Total appropriated funds,flacal year 19D2-----------_--- $~, ~, ~