Army Aviation Digest - Apr 1960

8/12/2019 Army Aviation Digest - Apr 1960

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LIBRARY US FT HUCKE L

PRIL 196


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U uteJ giate4 A '* I

VI TION IGEST

E D I T O R I A L S TA F FC A P T J O S E P H H POOLE

FRED M MONTGOMERY

R I C H A R D K T I E R N E Y

D I A N A G W I L L I A M S

ASOCCol Delk M Oden, Armor

RTICLES

MAINTENANCE APPRECIATIONCapt James E. Miller, Inf

WHAT'S A MAC CHART? .Capt William R. Swift, Arty

WHY TANDEM?CWO Ben G Thomas, TC

HE LEARNED ABOUT FLYING FROM THIS .Lt Ted N eu, Armor

SURVIV AL ON MOVING ICE .

WATCH YOUR MPLt Ivan D Butgereit, Armor

LESSON IN SILK .M/Sgt Charles E. Buchanan

RUSH HOUR

SMARTY FEVER S LETTERS FROM EDDIE .Lt William L. Patrick

A P R I L 1 9 6

V O L U M E 6

N U M B E R 4

3

6

10

13

17

21

25

28

30

ISLAND HOPPING. Inside Back CoverCapt Theo C Watkins, TC

TWX

PUZZLER

CRASH SENSE

DEP RTMENTS

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U S. ARMY AVIATION SCHOOL

Maj Gen Ernest F. EasterbrookCommandant

Col Delk M OdenAssistant Commandant

SCHOOL STAFF

Col Robert H. SchulzDirector of Instruction

Lt Col Jack BlohmCO USA A VNS Regiment

Lt Col John W. OswaltCombat Development Office

Maj Mark F. FowserActing Secretary

DEPARTMENTS

Lt Col Ritchie GarrisonTactics

Lt Col James B. Gregorie, Jr.Advanced Fixed Wing

Lt Col Harry J . KernMaintenance

Lt Col Thomas J. SabistonPublications andNon Resident Instruction

Lt Col G Wilfred JaubertPrimary Fixed Wing

Maj Alvin F. BurchRotary Wing

The U. S. ARMY AVIATION DIGEST ian official publication of the Department ofthe Army published monthly under thesupervision of the Commandant, U. S. ArmyAviation School.

The mission of the U. S. ARMY AVIATION DIGEST is to provide information oan operational or funct ional nature concerning safety and a i rc raf t accident prevention,training, maintenance, operat ions, researchand development, aviation medicine andother related data.

Manuscripts, photographs, and other illustrations pertaining to the above subjects ointerest to personnel concerned with ArmyAviat ion are invited. Direct communicat ionis authorized to : Editor-in-Chief. U. SARMY AVIATION DIGEST, U. S. ArmyAviat ion School. For t Rucker, Alabama.

Unless otherwise indicated, material ithe U. S. ARMY AVIATION DIGEST maybe reprinted provided credit is given to theU. S. ARMY AVIATION DIGEST and tthe author.

l he printing of this publicat ion has beenapproved by the Director of the Bureau othe Budget , 22 December 1958.

Views expressed in this magazine are nonecessarily those of the Department of theArmy or of the U. S. Army Aviat ion School.Unless specified otherwise. all photograph.are U. S. Army.

Distribution:To be distr ibuted in accordance with

requirements stated in DA Form 12.


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A

So

cExcellent Opportunity for Army Aviators to Further Their Military Care erColonel Delk M. Oden, Armor

F YOUR NEXT assignmentwere one of the command or

aff positions in Army A via-on, would you be confident ofour ability to fulfill the dutiesf the jO b? DO yO U possess theverall and detailed knO wledgeo qualify as a technical expert

n Army Aviation? Let s lookt the duties of a field gradermy Aviator whO is . assigned

s the DivisiO n A viatiO n Staf fOfficer.

The D O is charged with allp e c i a l staff responsibilitiesertaining to Army A viatiO n

within the command. In the

ame O f the commander, hemay exercise O perational cO n-O I of all O rganic aviatiO n units

which have not been assignedr t a c he d to subO rdinatenits within the command.

The aviatiO n staff O fficer suties are similar a t division,orps, and army cO mmand lev-ls with the difference arisingrom his increased scope of

supervISIOn a t higher levels.These are a few O f his mO reimportant duties: advise thecommander and staff on techni-cal aspects concerning capabil-ities, limitations, and opera-tiO nal characteristics of Armyaircraft; establishment and im-prO vement of airfields; advis-ing the commander and staff ondoctrine, t c t i c s , and tech-niques; monitoring the emplO y-ment O f aviatiO n within thecO mmand, and integrating theaviatiO n effO rt for mO re effec-tive utilization; and supervis-ing aircraft accident investiga-

tiO n and repO rts.He is further responsible fO r

a cO ntinuO us estimate of thesituatiO n and fO rmulation ofplans fO r the emplO yment ofassigned aircraft. These plansbecO me the basis fO r his rec-O mmendations to the tacticalcommander. He alsO effects co-O rdinatiO n with O ther staff ele-ments within the cO mmand.

These duties and resPO nsibil-ities are many and varied andrequire extensive administra-tiO n and supervisiO n. TO as-

sure himself and the cO m-mander that the Division A via-tiO n Company is capable ofmeeting these tactical require-ments, he administers strictcontrO l O f the individual andunit training prO grams. Hestrives to develO P the individ-ual O fficer s skill to assure max-imum utilizatiO n. His knO wl-edge that the demands O f mili-tary flying and variO US inflightemergencies require judgmentand skill to prevent disastrO usresults is tested daily. He alsOknO ws that these qualities re -quire time and effO rt to develO P

Colonel Oden is Assistant Com-mandant of the U S. rmy Avia-tion School Fort Rucker Ala.He is dual rated and in strumentqualified.


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APRIL 1960

and maintain. To. this end, hemQlds the training pro.grams to.meet the capabilities and experience level o.f his unit. Hemust also ensure that the aviators within his comm .and co.m-

ply with their annual requirem e n t s - a large but wo.rthwhileheadache.

A co.nstant check and recheck o.f individual abilities arenecessary to elimina e weaklinks and strengthen the unit'so.verall capability. This pro.gram will be repetitious in nature and co.ver all types o.f maneuvers. Lo.catio.n Qf the unitwill play a big part in thisphase, fo.r terrain and climateare maj o.r determining factorso.f aircraft perfo.rmance o.r individual abilities to. acco.mplishthe missio.n.

To cQnscientio.usly perfo.rmthe duties of the aviatio.n staffo.fficer requires skill, kno.wledge, patience, and perseverance - descriptive qualities o.fall go.o.d Army o.fficers.

The resPo.nsibilities Qf beingan Army Aviator are cQnstantly increasing as the pro.gramexpands and the overall dQc-trine Qf the Army flexes to.CQpe with the latest thQught Qnfuture warfare. ASOC is nQtlimited to seniQr Qfficers. AnyArmy Aviator who. has CQm-pleted his branch scho.QI is eligible to apply fQr admissiQn.

An excellent QPpo.rtunity isaffQrded the cQn sc i en t io u sArmy A viatQr to stay abreastQf current and pro.jected dQc-trine, Qrganizatio.n and principles o.f emplQyment by attendance at this co.urse, CQn-ducted a t the U. S. Army AviatQr Center.

ASOC is an 8-week CQurse designed to. give the Army AviatQr necessary training fo.r filling aviatio.n co.mmand and staffPQsitiQns. The co.urse Qf instructio.n co.vers all phases Qf

Army Aviatio.n, including: theArmy A viatiQn Pro.gram, Qr-ganizations, staff o.rganizatio.nand functio.ns, materiel, tactical emplo.yment, and researchand develQpment. ThrQugho.ut

the CQurse an active guestspeaker pro.gram is cQnducted.Addresses are made by representatives fro.m the Department Qf the Army, USCONARC, ARADCOM, etc. ThesepresentatiQns by pr Qm i nen tspeakers add interest and enhance the co.urse of instructiQn. Graduates of the AviatiQn Staff Officers CQurse areawarded MOS 2518 which qualifies them to. fill the many aviatiQn s t a f f po.sitio.ns in theArmy.

TQday, there are appro.ximately 1,600 Army aircraft inthe Type Field Army, and Qver5,700 in the actual Army inventQry. Army-wide, there areo.ver 6,000 authQrized co.mmissio.ned and warrant o.fficer Army Aviators. Mo.re than 18,000Qther persQnnel are assignedto the pro.gram. Within theCONARC Type Field Army,there are 352 Army A viatio.nco.mmand and staff po.sitiQns,either in Army AviatiQn units,o.r in the aviatiQn special staffsectiQns of divisiQns, CQrps andArmy headquarters.

In additio.n, aviatiQn staff PQ-sitio.ns are fo.und in MAAG Qr-ganizatiQns, N atio.nal Guard adviSo.ry gro.ups, the Federal A viatio.n Agency, industry, Research and Develo.pment, test

agencies, CON ARC and Department o.f the Army staffs, aswell as in the variQus servicescho.Qls. These totals are co.m-parable to. o.r surpass the totalnumber Qf co.mmand and staffPo.sitiQns fo.und in SQme Qfthe cQmbat arms Qr servicebranches.

No. Qne questio.ns the needfQr co.urses to. prQvide special

training so. the o.fficer is tho.Qughly gro.unded in the dutiand respo.nsibilities peculiarhis particular branch. Certaily a requirement exists to. prvide advanced training fQr t

Army A viato.r in his rapidly expanding and co.mplex field. Thart o f emplQying vast numbero.f aircraft to sUPPo.rt a tacticao.peratio.n and o.f so.lving thetricate and perplexing prQblems incident to airspace utilzatio.n canno.t be 0 b t a i n ethrQugh any Qf the brancCQurses Qr a t the : Co.mmanand General Staff CQllege. TA viatiQn Staff Officers Co.ursfills this vo.id.

In the field, units have befQrmed and do.ctrine has bedevelo.ped, sQm.etimes witho.the benefit o f adequate experence. There has been cQnsideable crystal ball gazing, amuch tho.Ught has been put inthese units and o.rganizatiQnsMQre is needed. There is a deinite requirement fQr the Qcer with imaginatiQn and fQrsigh in the reQrganizatio.n aestablishment o.f do.ctrine fArmy A viatio.n.

CQmmanders m u s t realizethe magnitude which ArmA viatio.n has achieved and timpo.rtance o.f h a v i n g wetrained and well qualified aviatio.n staff persQnnel. If we ato keep pace with the tremendo.US expansiQn no.w underwaywe must pro.vide fully qualifiedaviatio.n staff o.fficers to. methe grQwing need.

The A viatiQn Staff OfficeCo.urse presents an excelleo.PPQrtunity fo.r the Army Avato.r to. further his militarycareer. Thro.ugh it, Army Avato.rs and Co.mmanders are beter prepared to meet the chalenge o.f the Army's new mbility.

QUo.tas are available. Applnow.


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Maintenanceppreciation

M OST OF US are familiarwith high school and col

lege courses in Music Appreciation and Art Appreciation inwhich the students study thegreat masterpieces in each fieldas a part of cultural growth.I recommend a new course forArmy Aviators: MaintenanceAppreciation. I s k myselfthese questions: Do we avia-tors appreciate good aircraftmaintenance? And do we knowmaintenance and our aircraftthe way we should ?"

Too many Army Aviatorsha ve no real appreciation ofgood maintenance and don'tknow all they should about theaircraft they fly. Take the stu-dent go i n g through flightschool. What appreciation does

he gain for aircraft mainte-nance? During the course ofinstruction, he call s for a mechanic if something is wrongwith the aircraft, and usuallyends up taking a spare. Hes e I d 0 m sees equipment repaired. Contract maintenanceand a large fleet of aircraft seeto that .

Our young student aviator is

Captain James E Miller Inf

exposed to numerous mainte-nance courses; but he usuallysits there in a dream with asense of security (often false),believing that after graduationhe will be sent to a large aviation unit , a t least company size.And these units always have anoverflow of trained mechanic sand supervisory personnel

But put th i s young aviator inmy fledgling shoes. When Igraduated from flight school , Ireceived orders to a unit in Germany. On arrival, I found abattalion aviation section, allalone on a small airfield, withan u t h o r i z t i o n for twoL-19A's, two Army Aviators(lieutenants) , and three mechanics. Add to this, a toppriority mission that required

aircraft to be ready to go on amoment's notice. My big shockcame when the aviation officergreeted me with, You're goingto be the maintenance officer "

Things weren't too bad fora while , for I had the guidanceof more experienced aviatorsand the work of some welltrained and seasoned mechan-ics. But less than two years

later, I was the only aviator inthe battalion and I had threemechanics - one had beenschool trained on reconnaissance helicopters and the othertwo came with a 670.0 MOS.

I t wasn't long until I realizedmy job wasn't limited to read-ing magazines, playing cribbage, and flying operationalflight s . The magazines gaveway to TMs; instead of shuf-fling cards, I began leafingthrough forms of all sorts; andfunctional test flights appearedon my schedule. I found myselfspending more and more timeout in the hangar with the mechanics, helping t h e m solveproblems and supervising theirwork. Due to their inexperi-ence , they made a lot of honest

mistakes; someone had to catchthem before something serioushappened.

Captain Miller is chief o f t he672 B ranc h of the D epartment ofMaintenance USAAVNS F ortRucker . H e is dual rated and in-strument qua lified with approxi-mate ly 1 500 ight hours.


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APRIL 1960

This experience opened myeyes to maintenance and thenecessity for an aviator toknow just what is going on.But even this has not kept mefrom occasionally lapsing intoan apathetic t t t u d e andthinking: Why know all thisbusiness abDut how sO'methingworks? If i t runs, okay; if not,get a replacement. And this,I'm afraid, is all t O'ften theattitude among Army Aviators.Weare content to sit back andlet our mechanics dO the wDrkand the NCOs do the supervising.

I t is this matter of supervi-sion with which all aviators

should be vitally concerned.Army Aviation has sO me fineNCOs whO have been with thegame for a long time and reallyknow their way arDund theArmy's aircraft. However, a tthe present time, a number ofNCOs are just getting startedin aviatiO'n. When these peoplerepO'rt to field units, they willnaturally be used in supervi-sory slots. They might verywell end up as the line chiefof some aviation section wherethere is no other NCO to helpthem. I t must be realized thatthese men have nO more ex-perience, in some cases less,than sO me of the unit mechan-

Is your appreciation of main-ten nce limited to this idea:IIWhy all the fuss about main-tenance? If it runs, okay. Ifnot, get a replacement ? Orare you familiar with the c p -bilities of the mechanics in theunit and the maintenance re-

quirements of the aircraft s-signed you? e professional inyour attitude toward s fe main-ten nce practices.

ics. TherefO're, it is up to theofficers to give them a hand andget them started. They are going to make mistakes; andthese errO'rs must be cDrrected.

One answer t this problem

of inexperience is a good unittraining prO'gram fDr aviatDrs,supervisors, and me c h a n i c salike. Sure they've all been tschool and have received sO mQf the finest instructiDn pDSsible, but there are always someIQQse ends to tie up and locaprQcedures to learn. This training dDesn't have to' be run Dn anelabDrate scale; the size Qf theunit will determine the degreeQf fDrmality. With a small avi-ation sectiQn, training mightbe in the form Qf a bull ses-sion, with aircraft maintenance the subject instead Qgirls.

The material fQr unit training is abundant. One of the biggest problems Qf an aviatiQnunit is keeping up with the 781series fQrms. EverYQne seemst have a different interpretatiQn Qf the basic technical bul-letin; hence hundreds Qf differ-ent IQcal procedures and SOPs.This is an excellent place tostar t yO ur unit training. Letthe Old Timers pass alongtheir knQwledge Qf local grQundrules and just what's to be doneO n the fQrms. Get the new menO ff to a good start and you'llbe able to keep form consist-ency. Few people knQw everything abO'ut forms and records;sO take the opportunity Qfferedby a unit training program tobrush up and set up a unifDrmprQgram.

Technical manuals provideanDther source for training.Unless a person wQrks aroundTMs day in and day Dut, he for-gets the general contents Qf themanuals. An occasional periodQf training is necessary to keep


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people up to date and to refresh memories. Also, don'tput your new men behind the

eight ball a t the start bykeeping the TM files a big secret. Have someone lead the

new arrival around and showhim what you've got and wherethings are kept. Let him spendsome time browsing throughthe books so that he'll havesome idea of their makeup. tmay save a lot of time later on.

Many opportunities and situations may be found to givethe mechanics and the aviatorsadditional training. Occasionsmay a r i s e when something

different will come up in theway of aircraft maintenance

WO ACCIDENT - F R E Eyears of operation have just

been completed by the A viation Branch, U. S. Army Chemical Corps School, Fort McClellan, Ala. This record is a tribute to the attention of personnel to safety regulations. Noground accidents involving menor aircraft have occurred sincecreation of the Aviation Brancha t Reilly Army Air Field inFeb'tuary 1958.

Simple safety practices anddevices are the answer. Forexample, color contrast is usedto assist flight personnel inidentifying members of groundcrews. As the landing strip issurrounded by grass and wooded areas, maintenance personnel wear white coveralls insteadof Army fatigues, which are designed to blend in with openterrain. The sharp contrast ismore readily visible from theair and has contributed toReilly Field's o u t s t n d i n gsafety record.

A member of the ground

within your unit. A simple organizational modification mightbe required or a field maintenance team might arrive tochange an engine or o someo t h e r higher echelon work.

These opportunities should beused to give the less experienced personnel that little bitof extra training that mayhelp them nd you out a t somela er time. '

I am certainly not advocatingtha every Army Aviator be aqualified, school trained maintenance officer. The normal flyingproficiency requirements andthe additional duties heapedupon the officers preclude this.

However, I am suggesting that

crew, contrasted in white coveralls directs a pilot in the taxiing of the fixed wing aircrafton the landing strip. As per-

MAINTENANCE APPRECIATION

all of us should become morefamiliar with the maintenancerequirements of the aircraft wefly, and, more important, withthe capabilities of our mechanics. An aviator should never

have to ask a m e c h n i cwhether or not a certain condition is safe. He should knowthe necessary tolerances andlimitations. This is a mark of aprofessional Army Aviator.

Good aircraft maintenance isthe key to successful operations; and the key to goodmaintenance is adequate supervision of our personnel. To supervise properly, we must gainan appreciation of good aircraftmaintenance.

sonnel leave operations forwork assignments, they are reminded (by the message in theinsert) to t ke time to be safe.

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WHAT S M CCHART?

MAINTENANCE ALLOCATION C H A RT is a

guideline that determines theechelon to work on your air-craft and/or certain components. This little chart is one ofthe most important parts ofyour technical m a n u a I file.Faithful compliance with theconcept behind the MAC chartwill make for more efficientorgan iza t i onal maintenance.Your tech supply will be asmoother running branch of theorganization because i t will be

handling 0 n I y those repairparts essential to the categoryof maintenance you are engaged in organizational.

Pages 1-2 of your MAC chartgive a quick concise rundownof the why where when whoand how. Let s go a little fur-ther and t ry to explain more indetail what these two pagesmean

.6

Captain William R Swift Arty

First, the MAC as prescribedin ARs 700-18 and 750-6 is atechnical manual which appliest h e established maintenancec o n c e p t to each aircraft.There s one for every type ofArmy aircraft. The MAC assigns maintenance functionsand repair operations to be performed by e a c h echelon ofmaintenance. I t is the basisfor the establishment of toolsets the selection of parts, special tools and equipment andthe information in supply cata-

logs.These charts are developedby the Transportation MaterielCommand and submitted to acommittee consisting of representatives of TMC USCONARC the Army MaintenanceBoard the r m y AviationB o a r d , the TransportationSchool and the TransportationC o r p s Combat Development

Group with the TMC representative as chairman. Committee meetings are requested asnecessary by TMC. The policiesgoverning the implementationof the maintenance allocationcharts by activities and the decision as to whether a mainte-nance function is to be assignedto organizational maintenancemust be concurred n by TMCUSCONARC and the ArmyMaintenance Board. Any disagreements must be resolved bythe Deputy Chief of Staff for

Logistics.Once i t has been decreed that

Captain Swift is Chief Opera-tions Branch Department oMaintenance USAA VNS FortRucker Ala. He is dual qualified and has logged approximately4000 hmtrs flight time.


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QrganizatiQnal maintenance willnot accomplish the functiQn,he decisiQn as to which echeOon will accQmplish it is madeby the TMC representative.

Second, the MAC standard-izes the echelQn Qf maintenanceat which a functiQn will be per-fQrmed. For example, the re -placement Qf engines and cylinder and pistQn assemblies hasbeen assigned tOo third echelQnmaintenance for all aircraft.Deviations frQm this standardare based Qn the particular air-craft and the functiQns involved.Paragraph 3a Qf each MAClists the standards fQr deter-mining the echelQns of mainte-nance for each function. Fac-tors t o be considered in deter-mining echelQns are these.

Distribution of Aircraft: Thecapability of the maintenancefacility a t a Nike site whichhas, say, Qne Shawnee is nothe same as the capability Oof aShawnee CQmpany with SQme 21aircraft assigned. The assign-ment Oof aircraft within commands must alsQ be cOonsidered.FQr example, a fleet Oof 100 air-craft might generate a require-ment t o Qverhaul 40 struts. Ifall 100 aircraft are stationedwithin Qne cOommand it mightbe economical to Qverhaul thestruts; hQwever, if the 100 air-craft are distributed aroundhe world, it WQuid prQbably be

far more feasible and economical to destroy thQse that eQuIdnot be repaired at fourth echelon.

Frequency of Occurrence ofa Maintenance Function: A

maintenance functiOon may berequired SQ infrequently a t alower echelOon that i t justifiesevacuating the aircraft to ahigher echelOon or requestingpersonnel frOom the higher echelOonto dQ the wQrk. If the main-tenance function is a frequentOone the lower echelon may beauthorized tOo do the work.

Complexity of the Maintenance Function: If a specialistis required, there must be suf-ficient wOork tOo justify his as-signment - in Qther words,enQllgh to keep him busy. Specialists are preferred becausethey can dQ the jQb quicker andmore efficiently, and they candevelop shortcuts and specialtechniques tOo assist them. Specialists are naturally the besttrOouble shQoters when and

where needed.Range, Type, and Size of

Parts Required: Even thoughthe HU-1A IroquQis engine canbe changed in 30 minutes withCQmmon hand tools, i t is as-signed to third echelon as theirresponsibility tOo alleviate theproblem of getting the new en

gine to the unit and the old oneback. TOQ engines generallyfail gradually and replacementcan be scheduled.

Equipment Required: Carbu-retor repair requiring a flowbench is a fifth echelon function because most fourth echelOon activities dQ not have a suf-ficient amount Qf this type OofwQrk to justify the cost of aflow bench. However, fourthechelon can have Oone if needed.

Maintenance Manhours Re-

WHAT S A MAC CHART?

quired: A rule of thumb saysrequirements are Qne day forQrganizational and three daysfor third echelon to cQmplete aprescribed functiQn.

Administrative C o s t s In -curred: An example is the re -pair or Qverhaul Qf parts re -moved fQr cause. The overhaulcost of an item is carefully compared with the cost Qf a newitem. SQmetimes i t is moreeconomical t discard an olditem and use a new one. Anitem coosting less than $100.00must justify overhaul by alarge volume Qr a IQW unit overhaul price.

M o b i i t y Requirements:Maintenance f u n c t i o n s as -signed an echelon must not, because Qf equipment or man-hours required, interfere withthe desired mobility.

MOS Capability Available:Specialists assigned in certainareas where the volume of workis justifiably high might Qverrule any requirement to placethe maintenance a t a lowerlevel.

Now, with this small bit Oof

explanation, take another longlook a t yQur maintenance allocation chart; believe in i t ; giveit an honest trial. You willprobably find that yQur mainte-nance prQblems are fewer andthat you have mOore aircraftavailable fQr flight. This isbrought about because there ismore time .for thOorOough organi-zational maintenance; t t etroubles can be corrected. before they become too big tOohandle.

7


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FOR

AVIATIO N

C C I P ~ N TRESEARCH

L-26C RAN OFF RUNWAY DURING LOW VISIBILITY TAKEOFF IN HEAVY SNOW. NOSEGEAR WASHED OUT AND FORWARD FUSE-LAGE TWISTED. PILOT SUFFERED STRAINEDBACK AND CONTUSIONS. COP I LOT RE-CEIVED BUMP ON KNEE .

H-23D STUDENT PILOT HEARD LOUD CLANKING NOISE AT APPROXIMATELY 2 400 FEETAIRCRAFT SWERVED TO RIGHT. STUDENTPILOT ENTERED AUTOROTATION AND AIRCRAFT TOUCHED DOWN WITH NO DAMAGE.MAIN TRANSMISSION CASE CRACKED ANDOIL LOST. SYSTEM FROZE AND ONE-INCHDRIVE SHAFT SHEARED CAUSING LOSS OFANTITORQUE CONTROL.

HU-1A TAIL ROTOR DENTED TWO INCHESFROM TIP. DAMAGE FOUND DURING DAILYINSPECTION. CAUSE UNDETERMINED.

HU-1A PILOT SMELLED SOMETHING BURNING DURING CLIMBING TURN AT 200 FEET.HE REACHED AND LOOKED UP TO LEFT TOTURN OFF HEATER. AIRCRAFT ASSUMEDNOSEDOWN ATTITUDE AND PILOT WAS UNABLE TO RECOVER BEFORE IMPACT. PILOTSUFFERED BROKEN LEG AND HAND LACERATIONS OF SCALP. AIRCRAFT DESTROYED.

H-34 ENGINE FAILED AND PILOT COMPLETED FORCED LANDING WITH NO DAMAGE. FUEL STARVATION CAUSED ENGINE

FAILURE. APPROXIMATELY 400 LBS. FUELREMAINING IN FORWARD TANK. SUSPECTICE ACCRETION I N FUEL SYSTEM. TEMPERATURE 11 o f

H-13G ENGINE FAILED SURGED DURINGAUTOROTATION FAILED AGAIN DURINGPOWER APPROACH ATTEMPT SURGED RAP-IDLY AT GROUND CONTACT. AIRCRAFTSPUN TO RIGHT TURNED OVER. PILOT SUF-FERED SLIGHT CUT ON RIGHT HAND . AIR -

CRAFT DESTROYED. CAUSE OF ENGINE FAILURE UNDETERMINED PENDING TEARDOWNINSPECTI ON .

H-19C ENGINE RPM DROPPED DURING CLIMBAFTER TAKEOFF. PILOT BEGAN AUTOROTATION HELD AI RSPEED AT 50 K FLARED AT35-50 FEET TO SLOW AI RSPEED AND BU I LROTOR RPM. ROTOR RPM FAILED TO BUILDAND TOUCHDOWN WAS MADE WITH SLIGHTFORWARD SPEED. NOSE GEAR DUG INTSOFT GROUND AND MAIN ROTOR BLADFLEXED DOWN SEVERING TAIL BOOMCAUSE OF ENGINE FAILURE UNDETERMINEDPENDING ANALYSIS.

H-13E SKIDS WERE FROZEN TO GROUNDWHEN SKIDS BROKE FREE AIRCRAFT WENTHIGH INTO AIR AND PILOT BOTTOMEDPITCH . AIRCRAFT STRUCK GROUND ANDBENT SKID . NO INJURIES.

L-23D PILOT WAS INSTRUCTED TO USE AREADJACENT TAXI STRIP TO REACH RUNWAYBECAUSE OF SLI PPERY SURFACE. NOSEGEAR COLLAPSED I N SOD RUT. PROPELLERSTRUCK GROUND CAUSED SUDDEN ENGI NSTOPPAGE TO BOTH ENG INES.

L-20A STRUCK TELEPHONE WI RES DURI NGCLIMB FROM SIMULATED FORCED LANDINGDAMAGE TO PROPELLER LANDING GEAAND SKIN.

H-13E STRUCK HIGH TENSION WIRES DURING TAKEOFF . MAJOR DAMAGE. NO INJURIES . WEATHER NOT A FACTOR.

TL-19D ENGINE FAILURE OCCURRED DURING IFR FLIGHT. PILOT BAILED OUT LANDED SAFELY. LOSS OF OIL CAUSED ENGINEFAILURE. OIL FILLER CAP NOT SECURED.

H-13G SETTLED INTO SMALL TREES DURINGTAKEOFF FROM CONFINED TACTICAL HELI


11/40

s J l1 ebru ry nd m rch' ' ' ' ' 1 i I I I i I I

PAD. PILOT EXPERIENCED LOSS OF POWERAND COULD NOT MAINTAIN RPM. MAJORDAMAGE . NO INJURIES . WEATHER NOT AFACTOR. NO KNOWN MATERIEL FAILURE .

H-13E PILOT HEARD LOUD NOISE IN FLIGHTEXPERIENCED SEVERE VIBRATION . AI RCRAFT WAS AUTOROTATED TO LANDINGSLI D 20 FEET AND ROLLED TO RIGHT CAUSING MAJOR DAMAGE . FAILURE OF CONNECTING ROD BOLT SUBSEQUENT CONNECTING ROD FAILURE; NUMBER SIX CYLINDER CAUSED VIBRATION . NO INJURIES .

H-19D MAIN ROTOR BLADE STRUCK TAILBOOM AS AIRCRAFT ROLLED OVER ROUGHTERRAIN DURING FORCED LANDING . PILOTINITIATED FORCED LANDING DUE TO CONTROL LOSS . SUSPECT ICING OF PILOT VALVEON LATERAL SERVO .

H-23D STRUCK TELEPHONE WIRES WHILECONTOUR FLYING . EXTENSIVE DAMAGE TOMAIN ROTOR TAIL ROTOR AND TRANSMISSION . PILOT SUFFERED FRACTURED ARMAND BROKEN RIBS .

H-13E STRUCK UNMARKED WIRES DURINGRECONNAISSANCE FLIGHT . MI NOR DAMAGE TO PITCH HORN SWASH PLATE ASSEMBLY AND ROTOR ASSEMBLY . NO INJURIES.VISIBILITY LIMITED DUE TO SMOKE ANDHAZE . PILOT FLYING INTO SUN .

L-23D LANDING GEAR COLLAPSED DURINGLANDING ROLL CAUSING MAJOR DAMAGE .NO INJURIES . CAUSE UNDETERMINED .

L-19A SKIDDED INTO PARKED H-21C WHILETAXIING OUT FOR TAKEOFF . MAJOR DAMAGE TO L - 19; MINOR DAMAGE TO H-21.NO INJURIES . WEATHER NOT A FACTOR .

H-13H PILOT HEARD LOUD POP AT 150 -FOOTALTITUDE AND EXPERIENCED VIBRATION.PILOT WENT INTO AUTOROTATION; STATED

THE AIRCRAFT DID NOT RESPOND TO COLLECTIVE PITCH . SKIDS BROKE OFF ONINITIAL GROUND CONTACT AND AIRCRAFTPITCHED FORWARD NOSING OVER . M A INROTOR BLADES CUT OFF TAIL BOOM. NOINJURIES. FAILURE OF LEADING EDGE OFMAl N ROTOR BLADES CAUSED BY EXTEN

SIVE OPERATIONS ON DUSTY TERRAIN.L-19E PROPELLER STRUCK 1 L DRUM WH ILETAXIING . INCIDENT DAMAGE . NO INJURIES .

HU-1A COPILOT DOOR BLEW OFF DURINGHOVER STRUCK GROUND AND BOUNCEDINTO LOWER LEFT PLEXIGLASS NOSE SECTION . INCIDENT DAMAGE. NO INJURIES .CAUSE UNDETERMINED .

H-34C CLAMSHELL DOORS CAME OPEN INFLIGHT AND BENT BACK AGAINST MAINGEAR . DOORS DAMAGED BEYOND REPAIR .NO OTHER DAMAGE . NO INJURIES. CLAMSHELL DOOR LATCH MALFUNCTIONED .

H-21 C I NADVERTENTL Y FLEW I NTO FOG .PILOT LOST CONTROL DURING 180 0 TURNAND AIRCRAFT BEGAN STEEP ANGLE OFDESCENT. DURI NG RECOVERY ENG IN EOVERSPEED RESULTED IN PARTIAL ENGINEFAILURE . AIRCRAFT FORCED LANDED INOPEN FIELD WITHOUT OTHER KNOWNDAMAGE .

H-13G SETTLED I NTO TREES WHEN ROTORRPM WAS LOST . MAJOR DAMAGE TO MAINROTOR BLADES . NO INJURIES . WEATHERNOT A FACTOR .

L-19A PILOT DESCENDED FROM 5 000 FEETTO 500 FEET FOR LOW-LEVEL OBSERVATION PASS OVER GROUND TROOPS . ENGINEFAILED TO RESPOND AFTER DESCENT ANDMAJOR DAMAGE RESULTED FROM FORCEDLANDING . THERE WERE NO INJURIES . SUSPECT CARBURETOR ICING.

9


12/40

I N THE UNITED STATESthere are 60 manufacturersO f helicO pters. Only twO O fthese m a n u f c t u r e r s havechosen to produce the tandemcO nfiguration. Why have thesetwO chosen the tandem config

uration while the majority ofthe helicopter manufacturershave chosen to produce the single rotO r configuration?

If yO U are a submissive typeperson, you would probably saythat the single rotor helicoptermust be far better than O thertypes, otherwise such a majority O f manufacturers would notprO duce this type. However, ifyO U are an inquisitive type, youmight say that these twO companies must have a reasO n forprO ducing a different type cO n-figuration and maybe they havesO mething.

Apparently the Army mustthink the tandem cO nfiguratiO nhas possibi lities b e c a u s e i tplans t replace the H-21, H-34,and H-37 transport helicO pterswith the 2-3 tO n Chinook whichis a tandem rotO r heli copter .

10

CWO Ben G Thomas TC

It must be kept in mind tha twe are speaking O f configurations and principles, not O f specific helicopters. Present - dayconfiguratiO ns show the singlerotor helicopters to be lighterin weight with less wasted

space than the tandem configurations. This is due to themanufacturer s design, and future designs are utilizing allavailable space w i t h i n thestructure. In other words thenew designs are smaller O n theoutside, yet larger on the inside.

The utilization of this bulkywasted space in tandem designshould put it O n a more equalcompetitive basis with the sin

gle rotor helicopter in liftingcapability and forward speeds.While single rotO r helicoptershave been able to pick up heavier paylO ads than a comparabletandem rotor helicopter, thetwo will gross out at about thesame weight.

The same will hold true infO rward speeds. The more compact designs will naturally have

less drag-producing surface exPO sed to the relative wind, enabling the tandem helicopter toobtain much higher forwardspeeds with less PO wer. Thisalso is an economic factor intha t i t gives a much longer

radius of c t i o n when lesspower is required fO r cruise.The newer tandem helicopterwill have an approximate 350nautical mile rescue radius witha capability of a 15 person pickup. Tandem configurations arenot the only ones making thesestrides, but they are makinggreater progress to get on amore cO mpetitive basis with thesingle rotor configurations inthese aspects.

One O f the big problems inhelicopter stability is cO mpensating for the great amount of

C liro Thomas S ass7gned as aninstruct01 in the 674 Branch ofthe D epar tm en t of Maintenance.CSAAVNS Fort uc k er H e isrotary -wing ra t ed


13/40

torque that is the result ofturning the large rotor bladesnecessary for flight. The tandem configuration compensatesfor this torque by having twoequal sized rotors counterrotating thus utilizing all availablepower for flight by eliminatinga power consuming antitorquedevice. However the overlapping rotors require approximately 4 percent increase inhovering

powerover

the nonoverlap rotors. This increase inhovering p o w e r requirementfor the overlap rotors is compensated for by the reductionin structural weight and a reduction of drag in forwardflight. Hence the overlap tandem has the advantage of compactness and l o w e r weightwithout performance penalties.

The single rotor configuration must use a power consuming antitorque device. The onlyreason for the tail rotors on thecommon single rotor helicopteris to maintain directional control; i t does not produce anylift or forward thrust. Extensive testing has shown the tailrotor to absorb approximately8 percent of available power inhovering where the power requirement is high and 3 per-

cent under crUIsIng conditionswhere the power requirement ismuch less. However the tailconstruction to support this antitorque device is much lighterand less complex in structurethan the tandem configuration.

Another critical problem inthe helicopter field is center ofgravity travel. In this field thetandem configuration seems toexcel. Its large permissible displacement of the c e n t e r ofgravity permits wide latitude inthe placement of payload within the passenger-cargo compartment. The two longitudinally displaced rotors give theaircraft superior longitudinalstability and control permit-

WHY TANDEM?

Two equal sized counter-rotating rotors in tandemconf igura t ion compen-sates for torque elimi-nates power - consumingantitorque devices without weight or performancepenalties

ting indiscriminate personnels e t i n g and regrouping inflight.

Along this same line an airframe connecting two longitudinally disposed rotors allowsmaximum space for accommodation of payload with minimum drag - producing frontalarea. This permits the tandemconfiguration to carry large internal bulky loads without sacrifice of forward speed or maneuverability of the aircraft.

Some single rotor helicopters while still not having thiswide center of gravity displacement compensate for this limitation by the use of the offsethinge which allows the attitude


14/40


15/40

e

Learned

boutFlyingFrom

his

Lie u te nan t T e d N,eu, rm o r

You want to see me, Captain ?

Yeah, Lieutenant Fuzz, I

sure do Let's walk o.ut to theline a minute; I want to showyou something.

See those wrinkles on thewing there, Lieutenant?

Yes sir.Know what they are?No.t exactly, sir, but I think

they indicate some sort o fstructural damage - and may-be tro.uble fo.r o le Number 1,

since I was pro.bably the last tofly this airplane. But I don'tknow how they got there. Isure didn't do any violent maneuvers.

Let's go back to the officeand talk about it.

Lieutenant, you've succeeded in doing so.mething that isn ' tparticularly easy to accomplish.You've o.verstressed a Beaverand caused structural damage.As a matter of fact, I'd say youcame pretty close to augering

in. Since I 'm the safety officer,the maintenance officer re -ported i t to me. Of course, i tconstitutes an accident andwe'll have to have an i n y e ~ t i g

Lieutenant N eu s duq l ra t edand instrument quali fied . A grad-uate o f t he Universit y of South -ern a li fornia rm y viationSa fety Course L t N eu is t heFl ig h t Sa fet y Offi cer o f th e A r morCen t er viati on Command Fo rtK nox ]{entucky .

8


16/40

APRIL 1960

tiQn, but I'd like to. get someidea hQW it occurred before weconvene the board.

You were the last one to flythe airplane, I believe. Yougot back last night from a tripto Camp Swampy, didn't yQU T'

"Yes sir, but I couldn't havecaused the damage. I didn't doany aerobatic maneuvers a t all.This was just a straight administrative passenger haul. I toQk5 passengers and baggage dQwnto Camp Swampy MQnday andbrought them back yesterday.That's all there was to it.

There has to be a little mQreto. i t than that, because thatBeaver didn't wrinkle itself.Now how about weather? DidY U get into any turbulence?

Negative. We went dDwnearly Monday mDrning, and i twas real slick till around 1000.Then i t began getting just alittle bumpy, hut nDthing tomentiQn. I t was quite gustywhen we left Swampy yester-day, but certainly nDthing toget excited abQut. We alwayshave it this time Qf year. But

as fDr any real weather, no. Wewere strictly VFR all the waydown and back.

"Did anyone fly your airplanewhile yQU were a t Swampy?

No sir. I parked i t acrossfrom Swampy Operations andi t stayed there till we left yesterday afternoon. There musthave been something wrongwith the wing before this;thQugh to tell the truth, I neversaw those wrinkles during pre-flight."

That 's possible, of course.N QW hQW about the trip backyesterday; did you just takeoff and fly straight back?

N . sir, not quite. We to koff a little after 1500. YQUknow my passengers had gonedown to Swampy to coordinatefQr Operation Footblister this

14

fall. Well, just after I took QffColonel Crunchie asked if wecould make a recon of the ma -neuver area so. he could getsome idea of the terrain. Wesure did make a recon We flewaround between 45 minutes andan hour, and I had to changemy flight plan. Put us wayafter dark getting in. Theywanted to see every crQssrQadsand creek in the maneuverarea.

Did you do. any sort of maneuvers during the recon, andby this I don't mean aerobatics,but any real steep turns Qrdives ?"

Nothing particularly excessive, sir. I did make some steepturns to. give them a good viewof Qne thing and another.

N ow we're -beginning to getto it, Fuzz. I want yQU to. tellme exactly what you did fromthe t ime the colonel asked youto recon the area till you againstarted on your course."

"Well, I'm not trying to hideanything from you, sir. As Isaid, we took off from SwampyAAF about 1500, and abQut thetime I got to. 2,500 feet ColonelCrunchie asked if we couldmake a ' IQW reCDn of the - area.He was sitting in the right seat,incidentally. I went into a shallow dive toward a rQad junctionhe PQinted out. He said hewanted a gDQd 10Qk a t that par-ticular area. I banked prettysteep to give him a gQQd look aswe got down to. about 500 feetand then leveled out and flewdown the road.

We stayed about 500-600feet f r the rest Qf the time,flying all Qver the area, whileColonel Crunchie and his groupmade notes on their maps. Imade several fairly steep turnsduring the recon, but nothingunusual. After about 45 Qr 50minutes they had seen enough,

so I started to climb out on myheading. I came all the wayhome at 5,500 feet untilstarted letting down near hereThat's all there was to it, andI sure dDn't know how I couldhave done any damage to. thaa.irplane."

There a.re a couple Qf pointthere I'd like to. check. You sayyQU were about 2,500 feet whenthe cQIQnel asked yQU to. makea low-level recon and that yowent into , a shallow dive. DidyQur airspeed build up at aduring the dive?

I t built up a little I think.I pulled Qff PQwer to around 2inches and trimmed it nose-lowI'd say to around 125 knQts.

Now hQW abQut angle Qbank? HQW steeply did youbank?

"Well, pretty steeply. Maybe70 to 75 degrees."

And hQW about your attitude? Were you level Qr stidescending a t that bank?

If I remember right, sir, was still descending whenrQlled into the turn; then whenI reached 500 feet I began toroll Qut parallel to a road andlevel Qff a t the same time. I didget quite a tug in the seat of mypants, come to. think o.f it, bui t couldn't have been enough thurt the airplane. I've rackedthe DIe Beaver up that t ighIQts of times.

"Well, I think maybe it waenough to. hurt the airplaneHow about fuel? Did you have

the tiptanks full?Yes sir. The tr ip back i

normally around 5 hours, so.filled tiptanks so. we wQuldn'thave to stop.

How much baggage?"One small bag each. I'll tell

you, it's quite a jQb to. get sibig men plus baggage in a Beaver and still close the doors."

No. doubt. Well, Lieutenant,


17/40

your load combined with tho.semaneuvers was enough to putwrinkles n that wing, in allprobability. Let's s e e t h e weight and balance fo.rm forthis airplane and see ho.W muchweight yQU took Qff with. Doyou ever make out a weight andbalance form before you takeoff ?

No. sir, I haven't yet. Idon't have much time in theBeaver. Anyway, the IP toldme when he checked me outthat if yo.U could close the doorsit'd fly.

"That figures. Well, I'm gonna show you right no.w whythat 's a dangerous .piece of poop

to teach. Right here's the basicweight of this Beaver: 3,250lbs. That's the airplane as shestands, ready to load for a mission. I t dQesn't include gas, oil,or pilot. So. we add pilot and oiland that makes anQther 247lbs. We count 200 lbs. per person, since with a parachute it'llaverage out pretty well. Nowwe can start thinking about theload, which includes fuel, cargoand/ or passengers.

"Here's hQW you did it - Qrshould have. Gimme your pencil. You had 95 gallons of gasinternally and 43 gallQns in thetiptanks. That's 138 gallo.ns a t6 lbs per gallon, or 828 Ibs. offuel. Your Beaver then weighed3,250 lbs. basic plus 247 Ibs.pilot and oil, plus 828 Ibs. fuel,or 4,325 Ibs. Then you crammedin 5 people a t 200 Ibs., or 1,000Ibs. How much baggage?"

"Each Qf us had a small bag,about 20 Ibs. apiece, I'd say."Okay, there's another 120

lbs. So now we have 4,325 plus1,000 plus 120. That's 5,445lbs., right?"

Looks like it, sir.""What's the maximum gross

weight on the Beaver?"5,100 Ibs.

"Then yQU were around 345

lbs. Qver grQSS a t takeoff.Still, Captain, I don't see

what difference that makes.The airplane is stressed for3.5 g."

"That's just the PQint. Many

pilots don't realize that whenan aircraft is 'stressed' for somany g, i t means so many g a ta certain weight Now the Beaver was originally designed for3.5 g a t 5,400 lbs., which wasmaximum gross overload. Whatdoes this mean? Well, i t meansthat the wing spars, tail spars,fuselage - all the s t r u c t u r e -were designed so that a t 5,400lbs. gross weight the structurewould not yield a t 3.5 g. Inother words, it eQuId pull 3.5g at 5,400 Ibs. with no. damage.

"Let's take the wing fo.r example. I t c r r i e s the tQtalweight of the airplane in flight.That wing structure is designedfor 3.5 g t 5,400 Ibs. That is, itwill not yield a t 5,400 Ibs. multiplied by a load factor of 3.5. Thewing must be able to support,let's see . . . 18,900 lbs. I tdoesn't make any difference tothe wing whether you're pulling out of a dive at 5,400 lbs.and pull 3.5 g or whether youtake off - if yQU had the power, with a total gross weightof 18,900 Ibs. and fly perfectlystraight and level. All i t canfeel is load - so many pounds.

"N ow, we know the wing isgood for 18,900 Ibs. SUPPQseyou were not fully loaded andthe airplane weighed 5,000 Ibs.

The wing is still good for 18,-900 Ibs. Then you could havea load factor, or g, of 18,900divided by 5,000; that 's about3.9 g. To the wing or aircraftstructure it would be all thesame, see? As you decrease theweight you can increase thenumber of g you can pull.

All g is a lQad factQr-whatthe apparent weight of the air-

HE LEARNED ABOUT FLYING

plane is to the structure. If youbank and maintain altitude, fQrexample, you increase the apparent weight of the airplanebecause the vertical componentof the total lift must equal theweight Qf the aircraft. Here,let me draw a little sketch. Youremember from Principles ofFlight in school that the weightalways acts straight down andthe l if t always acts perpendicular to the wing span. Are youstill with me?"

Yes sir."Okay, w h e n yQU b n k

through some angle the l if tswings Qver to remain perpendicular to' the wing and i t

swings over an amount equalto the angle Qf bank, call i tangle a. Then the vertical component of the tQtal l if t muststill equal weight, or the airplane wQn't maintain I e v e Iflight, right? The horizontalcomponent of total lift will bebalanced by centrifugal fQrceacting in the QPPQsite direction,also, but we're nQt concernedwith that. SO I'll call the vertical cQmponent of lift, weight,too, and cQmplete the little triangle by drawing in this dottedline frQm the lift line perpendicular to the vertical component of the lift line, or weight.

So I have a right triangle,and I know from trigQnometrythat the cosine of an angleequals the adjacent leg dividedby the hYPQtenuse. In this case,the cQsine of the bank angleequals the weight Qf the aircraft divided by the total liftgenerated by the wing. Or,writing i t dQwn CQS (a)Now we define the load factor,or g, as l if t divided by weight,which figures, because the liftis what the wing feels, and i t 'sin PQunds, no.t g. That is, =g. I inverted the r ight side ofthis little equation, sO I've gotto invert the other side, and I

15


18/40

APRIL 1960

end up with this: c = W , oros a1

Cos a = g.You see, the load factor, or

g, is one divided by the cosineof the bank angle. Up to abDut45 you don't pull many g in a

level turn.FDr

example, thecDsine of 30 is about .866, sothe IDad factor for a 30 bankis Dne divided by .866 Dr 1.16 g.At 45 , the co.s,ine's .707 andyou pull 1.4 g. At 60 , you pull2 g and if yo.U were a littlesteeper than 70 0 , say 72 Dr 73 you pulled right around 3.3 or3 4 g.

Provided your airplane hadnever been overstressed before,and y o u r passengers didn't

mind, this wDuldn't have beentoo bad, because i t was a Io.adof 5,430 times 3.3 or 17,919 lbs.on the wing, knocking off somefor gas used up. Y DU wouldn'thave pulled this magnitude un-til you reached a constant al-titude turn attitude, either. Buthere's the joker: you also beganto pull up and roll out a t thesame time you were rackedover in the steep bank.

Now a rolling pull out isabout the hairiest maneuveryou can do as far as stressingthe airplane is concerned. Whenyou pull out, you put additionaldDwnward forces on the Io.Wwing. In this case the rightwing, because there has to bean unbalanced upward force onthe wing to start the roll Dut.This is logical, too, because in aroll out the aileron deflects

dDwnward on the low wing, in-creasing the lift Dn that wing.At the same time the lift wasreduced on the high wing dueto the upward deflection f theaileron. These last two forcesare too. complicated for me tocompute, but they are signifi-cant. When you add them tothe 17,919 lbs. total load youalready had due to bank, theyput the low wing in an over-loaded cDndition because i t wascarrying more than its half ofthe tDtallo.ad due to downwardaileron deflection.

On tDP of all this, it 's alwayspDssible that you hit a gustjust a t this critical time. That

would have increased your loadf c t 0 r even more. Result?Structural damage. Had YDUbeen a t a Io.wer gro.SS weight,YDU might have gDtten awaywith it, but that all depends onhow much IDwer and how greatthe o.VerlDad D n the IDW wingwas.

But sir, I thought o.ur air-planes all had a safety factorbuilt in. If that 's so, then Istill sho.uldn't have hurt thestructure.

YDu don't understand whata safety facto 'r is. All aircraft,by FAA regulatio.ns, must havea t least a safety factor of 1.5.But that means Dnly that youcan load the structure up to1.5 times its design IDad onceand it wDn't CDme unglued. I tdoesn't mean there won't bedamage or that i t wo.n't break

I YOU NOW

the second time. If the Beaverwing is built to take 18,900 lbs.withDut causing any permanentdeformatiDn f the structure,then it can take 1.5 times thatI 0 a d Dr 28,350 lbs. withDUtbreaking once I t could breakthe second time though.

If it weren't for this, we'dbe policing up the wreckage outin the boondocks right n D W. Butif you exceed the 18,900 Ibs.IDad Dn the wing or 3.7 g athe 5,100 lb. maximum grossweight, you can get structuraldamage. You have just provedthat when you exceed the design load factor a t an overloadweight you get structural dam-age. I t can be done; thosewrinkles pro.ve it. The wing'llhave to be replaced and the resto.f the structure checked fordamage. Do you understandwhat I've tried to tell you?

Yes sir, I think so. I wishI'd known this yesterday.

I wish you had too. But justto make sure everyDne elsekno.ws it, I want YDU to startpreparing a class on this for therest o.f the pilots. I'll get icleared through the training officer. Understand?

Yes sir.All right, get out of here

and reflect on your sins awhile.We'll have to have a statementfor the investigation, too. Anyquestions ?"

Yes sir. May I have mypencil back, sir?

That a headwind 100/0 of landing speed will reduce landing distance 190/0 and the reverse itrue for a tail wind?

That 200/0 increase in weight is. eQ ual tQ 440/ ) i n ~ r e s ein landing distance?

16


19/40

ECENTLY 29 CIVILIANand military sc ien t i s t s

were evacuated f r o m theirlaboratory ice floe as i t slQw-

ly crumbled into the sea about400 miles northwest of BarrowAlaska. The rescue Qf men and

scientific equipment went offsmoothly despite some anxiQusmQments w h e n the breakupquickened and h u g e cracksinched toward the main camp-site.

Fortunately rescue t e m swere constantly standing byand no Qne was left to fight forsurvival on a cake of ice float-ing in a treacherous Arctic sea.

This possibility is ever pres-ent for Army Aviators on dutyin Arctic and Antarctic zones.Knowledge of prQper survivaltechniques may spell the differ-ence betwe en life and death forthe crashed aviator who findshimself on an ice floe.

Just about the mQst miser-able predicament imaginablefor an aviator is to be dQwn onmoving ice in the Arctic Ocean

7


20/40

APRIL 1960

or Bering Sea. However all isnot hopeless. Enough possibilities exist to justify reasonablehope for survival. With a minimum of equipment an averageconstitution, and a strong willto live the unfortunate has afair chance. But we must notfool ourselves. Land survivalis relatively easy. On movingice there is little to work with.

Except for the coastal fringeand large or small bays andnarrow straits between islandsall Arctic ice moves with thecurrents. During October andNovember the ice moves south;in May and June the packmoves north again. Betweenthese months, i t may movenorth for two days and thensouth for four days. I t is notunusual for the currents tochange three times in 24 hours.

Many current movements arelocal. In the middle of the Bering Sea the ice seems to movein an eddying motion. Furthernorth, the ice all seems to movetowards the Bering Straits, oraway from them in a fan-likeshape.

Two types of ice abound inthe B e r i n g Sea and ArcticOcean: the main ice pack thatnever completely thaws outand the new ice formed eachwinter. In the fall of the year,the ice pack m v e s downthrough the Bering Sea andspans out all the way fromSiberia to Alaska extendingdown usually as far as Nunivakand the Pribilof Islands.

When the weather gets verycold the open water betweenthe spread - out freezes thethickness of the new ice depending on the amount of openwater. The movement of thecurrent forces the ice up intosmaller or I a r g e r pressureridges. The ridges are largerwhen the surrounding ice is

8

heavier or when close to shoresince in those cases there ismore resistance. Consequentlyin the center of the Bering Seathere are small ridges and lotsof smooth ice. Along shore andaround the islands the ridgesare much larger and more compact.

The ice usually moves up to4 miles an hour, although incertain localities such as theBering Straits, it might moveas fast a t 7 mph. Once it wasmeasured between the two Diomede islands and was found tobe moving north a t 9 mph. Menhave been known to drift 100miles n 24 hours, but againmen camped on a large isolatedfloe have moved less than 5miles in that period of time. tis not unusual for hunters totake off against the ice andtravel out 15 miles and be eventually carried home.

When traveling on movingice keep in mind that you arein an unfortunate situation. Nomore lonely situation is imaginable. One is tempted todespair and make no effort tosurvive. Nothing around seemsto be of any help. Ice extendsas far as the eye can see. Noshelter seems available. Thereare no edible grasses, no birdsno trees, no animals movingaround that can possibly becaught, very often no sun nothing that can be used for makinga fire no one to consult no oneto rely on ; in fact, nothing

Yet men have been known tosurvive on moving ice for aslong as 5 weeks. t is not unusual to be out 2-5 days as amatter of routine that causesno concern. In the past 10years, 40 men have been outfor periods ranging from 3-10days and all survived with fewill results. They made use ofthe equipment they carried.

These men were Eskimos butany white man can do the samething provided he uses commonsense has great patience andthe necessary stamina. A service man is conceded to havecommon sense; he can develop

patience willingly or unwillingly as circumstances dictate,and the stamina is taken forgranted.

SURVIV L SUGGESTIONS

A shelter can be made ofsnow; or if snow is not available use slabs of thin ice. Makei t as small as convenient soless area will have to be heated.

Use the lee side of a pressureridge that seems old and solidpreferably a little in from theedge of the ice. Don't be elaborate about it as it will not beused for a long period unlessyou are on an isolated floe. Thisshelter can be made with thehands alone if necessary. Sealblubber can be ignited to furnish heat. An initial hot flameis necessary so v r y o n eshould carry heat tablets andmatches. Light the tablets onthe raw side of the blubber withthe hairy side on the ice. Oncethe blubber catches fire and its h 0 u I d if four tablets areburned at once you have a goodfire. A square foot of blubberwill burn for several hours.

Blubber fires need no shelter; in fact, the stronger thewind the better the fire. Tinderof any description burned with

the heat tablets will help butonce the blubber catches firesave your heat tablets. Thesmoke from this fire is dirty,black and heavy but not nauseating. Its flame is v e r ybright and can be seen fromseveral miles away. The smokewill penetrate your clothes andblacken your skin but no onewill be around to object any-


21/40

way. I f yQU are Qn a large iSQ-lated flQe, build the fire nearthe Qpening Qf the shelter, Qutside, Qf CQurse. A IQt Qf theheat will enter the shelter. Theburned blubber cinders are edible; in fact, carbQn frQm sealQillamps was the original Eski-mO' chewing gum.

I f unfO'rtunate enQugh to' bestranded o.n mQving ice, the fQl-IQwing procedure is advised. I fyQU knQw yQur directiO'n, prQceed towards the nearest land.If the ice is gQQd fo.r traveling,i t is advisable to' leave thenlane, unless yQur CQurse wasfQIIQwed and yQU expect to bep-icked up Qr sPQtted. The ice

might be drifting away fro.mRafety. Besides, ice flQes farfrQm land o.ften break up. Thechances Qf an aircraft beingseen Qn the ice are less than Qnland.

The decisiQn t stay with orabandQn the aircraft is up to'the individual. If i t is O'n alarge, SQlid, reasQnably isO'latedflQe, perhaps it is better to' re -main with it. If it is dQwnamQng the pressure ridges QnmQving ice, it 's better to leaveit, because it wQn't be abQvethe ice very IQng anyway. Manyparts Qf the aircraft equipmentcan be used, such as extra clo.thing, small life raft , and any-thing else that can be carriedwithQut too much effQrt. Aspear to' test the ice shQuld beimprQvised, but it need no.t beelabO'rate. Much will depend Qnwhether Qr nQt distress signalswere sent Qut. I f they were andyQU are sure yQU are Io.cated, re -main in the vicinity. I f nQt, i tis better to' mo.ve and keeptraveling until yO'U CQme to' theshQre ice, Qr until yO'U find a flQeyQU think will last SQme time.

If yQU are gQing to' walk tQ-ward knQwn land Qr So.lid ice,either with Qr against the ice,

Qbserve the fQIIO'wing precau-tiQns. The Qnly danger is cross-ing frO'm Qne flQe to anQther.When Qbliged to' jump, dO nQttake Qff frQm the edge Qf apiece O'f ice, but ra ther a cQupleQf feet from the edge. This lessens the chance O'f the ice turn-ing o.ver. When the ice is clQsely packed, yQU can walk asthO'ugh it were all SQlid, usingQbvious CQmmO'n sense. YQU caneasily nO'te if the tQuchingedges Qr, in mQst cases, Qverlapping edges are SQlid enO'ugh.

When large, heavy ice flQestouch each O'ther, an added pre-cautiQn is necessary. Usually,the ice between the flQes has

been grQund intO' a PQwder, andcan bear no. weight; but, mQV-in . with the PQwdered stuff,will be larger chunks that willhQld yQU up. This situatiQn iseven mQre prevalent wheremQving ice tQuches the SO'lidshQre ice.

When crQssing p r s s u r eridges, be careful to. step Qnthe ice Qnly. Bridges Qf snQWcan be formed between thepeaks Qf ice, and these are nO'talways solid. One can fall 20feet dQwn. The powdered icemay be as much as 20 feet wide,but by moving against the iceyQU will usually find a place to'crQSs. During the winter andspring mQnths, the flO'atice Isalways SQlid enQugh to' hQld afreight train. Until DecemberQne must be careful, as the pat-ches Qf new ice may nQt be mQrethan three inches thick. In midwinter and spring, a gQQd wayto' test new ice alQng the edgesQf SQlid ice is by Qbserving the

frQst flQwers."On the lee side Qf SQlid ice

and especially alQng the Qff-shQre line, smQQth new ice willfO'rm, starting a t and extendingaway frQm the SQlid ice. I twill cQntinue to' fQrm and ex-

SURVIVAL ON MOVING ICE

tend until the current changes.Then the heavier ice cQmingagainst i t will push it up intoridges. These frost flQwers"will begin t fQrm when the iceis one day Qld. They look likesmall fern plants and come upscattered like grQwing CQrn. IfyQU have nO Qther means, suchas ice spear Qr knife, to' test it,the ice is safe to crawl Qverwhen yQU can make a distinctfQQtprint. In general, sea ice 4inches thick will hold just abQutany man.

YO'ur fQod supply will beseals, and fQr that yQU need arifle. There are always sealswhere there is mQving ice. They

CQme up to' breathe in thepatches Qf Qpen water, withtheir heads abQve water fQrperhaps 30 secQnds. They arenever Qn the ice until May andJune, and then Qnly occasiQnally. Usually. they dO not sinkwhen shQt. The head, neck, andshQulders are the Qnly parts visible and a head o.r neck shotwill always kill them. WhetherQr nQt they sink when shQt denends Qn the amQunt of blubber. The number that sink isabQut Qne in five.

Durinl February and March,the male seal has a disagreeableQdO'r, but this dQesn't affect thetaste Qf the meat to.Q much.MQst parts Qf the seal can beused. The skin can be used to'make mQccasins if necessary.The blubber can be used fQrfire, and the flesh eaten. FrQzenseal meat, especially frQzenliver, is palatable and easilyswallo.wed. When a seal is shQt,a grapple hQQk and line are usually necessary to' bring i t in.If these are missing, Qne canmo.ve arQund to. the ice wherethe animal will eventually drift.Seals are mQre plentiful a t day-break and evening, but they areliable t pop up at any time Qf

19


22/40

APRIL 1960

the day a t any place.The following items are sug

gested as minimum necessaryequipment for survival:

1. firearm of some description;

2. an abundance of heattablets;

3. waterproof m t c h e s ormatches in waterproofcontainer;

4 small grapple hook andline;

5 necessary stamina n dcommon sense.

Moving ice can be frighten-ing. Blocks the size of a largeroom can be upended. I t makesa grinding and squeaking noise.Several miles of i t might bepiled up like some bombed-outcity and be moving along a t 4mph.

Here are a few examples ofmen who have survived on moving ice. Recently one man sur-vi ved 11 days on moving iceduring very adverse weather.Several years ago a King Is -land boy was out 6 days whenthe temperature was 22 0 _ 42 0below with a strong wind. Hetraveled when the weather wasbetter and holed up when toocold and windy.

Five men were out for 32days. They lived on seals alone.The ice traveled a long time inthe opposite direction f r o mhome but they simply campeduntil the currents became morefavorable.

In the late 1930s a white manwas 4 days and nights on theice. He was on a large isolatedfloe and remained there until

it drifted close enough to othermoving ice and eventually gotto an island in the B e r i n gStrait. He k e p t reasonablywarm by alternately joggingaround on his ice floe in as fewclothes as possible and sleepingfully dressed in an ice shelter.When lost his equipment consisted of the hunting clothes hewas wearing 30-30 rifle 8shells one pair of gloves a canof tobacco and some cigarettepapers and matches. He saysthe only thing that botheredhim particularly was the silence.

One U. S. corps soldier yearsago drifted around for 18 daysthen eventually made the solidice. And the Army requiredhim to make up the lost time

Part of the training equipment used t Ft Carson to te ch cold weather survival to Army personnel

20


23/40

WATCH

Y UR

mp

Lieutenant Ivan D. Butgereit rmor

HAT IS manifold pressure? Where does i t comefrom? What does . i t do? Cani t damage an engine? Does ithave any effect on fuel economy? Is there a relation between manifold pressure andpower? The answers to thesequestions -should be known byall Army Aviation personnelregardless of the type aircraftthat they are flying or performing maintenance on.

Manifold p r s s u r e is thepressure in the intake manifold. Let us illustrate howmanifold pressure is formed bylooking at a diagram of onecylinder of a nonsuperchargedengine.

If the cylinder diagrammedfig. 1) were operating, each

time the piston moved down in

the cylinder on intake stroke, alow pressure would be created.Assuming that the intake valveis open, t h i s low press urewould also be found in the intake manifold. Why? Becausethe butterfly valve in the carburetor will allow only a givenvolume of fuel-air mixture toenter the manifold. If the butterfly valve is opened to themaximum, the pressure in theintake manifold will t ry toequalize with atmospheric pressure. (With engine running,manifold p r s s u r wouldn treach atmospheric pressure because of the friction lossescaused by the fuel-air mixtureas it passes through the inducti@n system.) The throttle controls . the position of the butterfly valve. In turn the butterfly

Figure 1

INTAKE VALVE EXHAUST VALVE

M NIFOLD PR SSUR o PISTONI==========t

25

~MANIFOLDPR SSUR

valve controls the amount offuel and ir which can enterthe intake manifold. With thethrottle open slightly, the butterfly valve will only be opena small amount, and the enginewill run a t a slow speed with alow manifold pressure. As , thethrottle is opened, the butterfly valve opens, manifold pressure increases and the enginedevelops more power.

On supercharged engines, themanifold pressure works in exactly the same manner exceptthat the fuel-air mixture iscompressed and the manifoldpressure can ex ceed atmospheric pressure. An engine issupercharged to increase manifold pressure a b ov e atmospheric pressure to provide highpower output for takeoff andto sus ,tain high power output a thigh altitudes where atmos

pheric pressure is low. The following diagram fig. 2) showsthe relation of horsepower tomanifold pressure for a certainengine.

Lieu t enan t B utge r eit is an in -structor in t h e P owe r p la n tB ranc h D epar tmen t of Ma in t e-nance US V NS . H e :S xed-wi ng q ua li ed .

2


24/40

1100

900

a ::w

0D.. 700wena ::

0:x:

500

300

/

//

11//

/

20 25 30 35 40 45 50

MANIFOLD PRESSURE IN OF Hg )

Figure

Power is increased by increasing manifold pressure intwo ways.

1. t increases the weight ofthe fuel-air mixture deliveredto each cylinder on each intakestroke of the engine. At a constant temperature, the pressureof the fuel-air mixture will determine the weight of the fuelair mixture that can be contained in a given volume ofspace.

2. I t increases compressionpressure. The greater the pressure of the fuel-air mixture atthe beginning of the compression stroke, the greater willbe the compression pressure(pressure of the mixture a t theend of compression stroke). Ahigher mean effective pressureand consequently a greater en-

gine output will be caused byhigher compression pressures.

To illustrate the increase ofthe compression pressure (fig.3): In cylinder A with an intake pressure of 36 inches ofmercury, the compression pressure is 270 inches of mercury,as shown in AI In cylinder Bwith the same compressionratio with an intake pressureof 45 inches of mercury, thecompression pressure is 405inches of mercury as shown inB 1 As has already been noted,the higher the intake pressure,the higher the compressionpressure.

t w 0 u I d appear that the

manifold pressure could be increased indefinitely to obtainmore power, but it must be emphasized that this is not true.Excessive manifold p r e s s u r eadversely affects the operationof the engine and ultimatelydamages it permanently.

Manifold pressure is indicated by a manifold pressuregauge. A pressure sensitivemechanism located in the manifold pressure gauge is con-

o nected to the induction systemby a pressure line. The movement of the diaphragm in thepressure sensitive mechanismis increased by a multiplyingdevice and transmitted to thepointer of the gauge. The manifold pressure gauge is usuallycalibrated in inches of mercury.On a supercharged engine the

Figure 3

270 in. Hg405 in . Hg

36 in .Hg o 45 in Hg o

o u o uu u

A BB

22

pressure line goes from thegauge to a point in the supercharger that is subject to theexact supercharger dischargepressure. On non superchargedengines the line will go directlyto the intake manifold.

Have you ever wondered whythere is no manifold pressuregauge on an L-19A or E? Wedon t need one on a nonsupercharged engine using a fixedpitch propeller because we canread the rpm from the tachometer and thereby get an adequate indication of the powerbeing developed by the engine.I t is necessary to have a manifold pressure gauge on any air

craft which has a constantspeed propeller, since the pilotcould not tell how much powerthe engine is developing without it. This is true because anincrease or decrease of thethrottle only changes the bladeangle of the propeller and notthe rpm (within the limits ofthe propeller governor).

How is manifold pressurechanged? Obviously, if thethrottle is opened while the engine is running, the manifoldpressure will rise. As higheraltitudes with l o w r atmospheric pressure are reached,the manifold pressure will decrease (assuming a constantthrottle setting). We can alsochange the manifold pressureby changing the rpm of the engine. The resulting increase ordecrease in rpm will change themanifold pressure because the

mixture flow in the cylinders ofthe engine will be altered. Thisis the reason for the change inmanifold pressure when theconstant speed propeller is exercised while maintaining aconstant throttle setting.

Manifold pressure is one ofthe causes of detonation. Detonation is abnormal combustion,which has a very adverse ef-


25/40

fect on the engine. 0 t h e rcauses of detonation are: fuelwith too Iowa resistance to detonation; h i g h cylinder headtemperature; using too lean amixture.

While i t is possible to provideessentially the s m e horsepower using several power settings manifold pressure andrpm) when operating with aconstant s p e e d propeller, apower setting with a low manifold pressure and high rpm offers an advantage in detonation prevention. Excessive engine speeds waste power inovercoming friction losses, produce abnormally rapid enginewear, and are uneconomical infuel consumption.

The relationship b e t wee nmanifold pressure and powercan be understood if i t is remembered that the horsepowerdeveloped by any engine is afunction of torque and rpm.The following table from FAAManual 107 shows the horsepower required to turn a fixedpitch propeller a t a given rpm.

rop rpm Required hp1,000 801,500 2702,000 6402,500 1,2503,000 2,160This table applies to only one

particular propeller. L a r g e rpropellers will require m r ehorsepower for any given rpm;smaller propellers will requireless. But the relation betweenrpm and horsepower will in allcases be given by the formula:

hp = K x r p m 3

K is a constant whose valuedepends on such factors as airdensity, and the number, size,shape, and blade angle of thepropeller.

As the rpm becomes higher,the additional horsepower required to produce a given in-

ossible effe t of high compression pressure

crement in speed say 500 rpm)increases very rapidly. Only190 additional horsepower arerequired to raise the rpm of thepropeller in the example from1,000 to 1,500; but 910 extrahorsepower are needed to raisethe rpm from 2,500 to 3,000.

Since speed is the only meansof regulating the torque, andhence the power absorbed by afixed - pitch propeller, if thepower output of the engine ischanged, the engine will accelerate or decelerate until an rpm

is reached a t which the powerdelivered is . equal to the powerabsorbed. In the case of theconstant speed propeller a giventorque may be absorbed a t aninfinite number of rpm bychanging the b I a d e angle).Since power is a function ofboth torque and rpm, a particular horsepower may be developed at an unlimited number

of torque-rpm combinations.Keeping the foregoing facts

in mind, let us examine theprocess by which the torqueabsorbed by the propeller isproduced and delivered by theengine. The process is the familiar one of applying a forceat right angles to an arm. Thecomplications n this instanceare that the amount of theforce and the length of the armare continually changing. Theforce is a varying pressure -the pressure exerted on the pis

ton by the gases expanding inthe cylinder. This force reachesi ts maximum shortly after thebeginning of the power strokeand acquires a negative value,in effect during the compression stroke. In spite of the factthat an engine actually deliversits torque unevenly, the frequency and duration of thepower impulses, together with

3


26/40

AP;RIL 1960

the mQmentum Qf the mQvingparts, make i t PQssible to CQnsider torque and with it PQwerand rpm as being continuallyproduced.

TherefQre, any factor whichaffects the average pressureacting Qn the piston will changethe tQrque. If the mixtures t r e n g t h temperature, andtype O f fuel remain unchanged,the pressure develQped in thecylinder will d e p e n d O n themass Qf the charge that can befO rced intO it. This in turnwill depend Qn the manifQldpressure. Thus tQrque turnsQut to be a functiO n O f manifO ldpress ure and varies directly

with i t thrQughO ut almQst theentire O perating range Qf theengine.

Horsepower in effect thenbecQmes a function Qf manifoldpressure and rpm. As the thrQttIe is increased Qn aircraft witha fixed-pitch prQpeller, the rpmincreases. The engine then develGps . its greatest power whenmanifO ld is a t the highest figure, since this will correspondwith maximum rpm. On engines with CQnstant speed prQpellers, the engine runs a t acGnstant Gr set rpm; and whenthe thrGttle is Qpened manifoldpressure, tO rque, and hQrsePO wer all increase. The additiQnal power is absGrbed by theprGpeller, as i t will change toa higher blade angle. In fact,pGwer may be increased with-Qut a change in rpm until maxi-mum manifQld p r e s s u r e isreached, or until cylinder pres-sures becQme excessive O r detQnatiGn begins.

In t h e 0 r y , the maximumPQwer shQuld be develQped a tmaximum permissible manifO ldpressure and rpm. In practice,the characteristics Qf super-charging and vGlumetric efficiency vary with engine speed.A change in engine speed will

24

usually be fQllGwed by a changein manifQld pressure, if thethrQttle is left unchanged. FQrthe same r e a s 0 n maximumpower a t cO nstant manifQldpressure is nQt necessarily Qb-

. tained a t highest speeds. Fur-thermGre, because Qf variatiQnsin prQpeller efficiency w i t hchanges in blade angle and rpm,maximum prGpeller t h r u s thO rSepO Wer does nQt necessarily cQincide with maximum engine hQrsepQwer.

t is desirable to run an engine a t the IQwest pGssible rpmcO nsistent with prQpeller andengine efficiency. FrictiQn isthus reduced; Qil and fuel CQn

sumptiQn are alsO reduced. Theengine running a t a low rpmwill have high cylinder pres-sure which will prQduce themQst PQwer O r force to drivethe p i s t 0 n dQwn Qn PQwerstrQke. Naturally this is assum-ing that cylinder pressures arenQt excessive. TO get awayfrO m excessive cylinder pres-sures the pilQt may gO to ahigher rpm and IQwer manifO ldpressure. This will result inmO re frictiQn to be GvercO meby burning mQre fuel. Higherrpm alsO leads to higher reciprGcating loads and the enginewears Gut faster. PrQper O peratiGn therefQre lies sQmewherebetween these twO extremes.

As manifQld pressure is increased, cylinder pressure increases, thereby putting IQad Qnthe internal parts Qf the engine.There has to be a limit tothe stresses imposed O n theseparts. Likewise, excessive rpmcannQt be allQwed because Qfthe danger Qf setting up excessive centrifugal and reciprQcating fQrces. I t is alsO pGssiblethat detGnatiQn may be the deciding factor in establishing asafe limit fQr either manifoldpressure Gr rpm with a certain

grade Qf fuel. Other limitingfactors CGuld be cylinder andQil temperature, and Qil andfuel pressure. Hence, the familiar red lines Gn the instru-ment panel. OperatiQn withinthe limits assures dependability, as amply demQnstrated bythe tests required by the military prQcuring Qr regulatingagency. When Qperating O Utside these limits, the pilQt isrelying Qn unprQved margins Qfsafety.

I t is a knQwn fact that take-Qff r e q u i r e s the maximumamQunt Qf PQwer. TakeQff, hQwever, is a cGnditiQn with definitetime limits. TO Qbtain takeQff

PQwer fQr cQntinuQus QperatiQnWQuld require a larger engine.AllQwances in the form Qf limitatiO ns fGr the high power Gutput during takeoff fQr shQrtperiQds Qf time are made pri-marily to increase the efficiencyGf the aircraft. SQme aircraftengines can actually be runcQntinuGusly w i t h manifQldpressure and rpm abO ve the redline limits. When this Qccurs,

the periQd Qf reliable engine QPeratiQn is reduced.The limitations O f the air-

craft engine are very real. Themaximum manifO ld pressureand rpm limitatiGns are paintedQn the instruments. Except fQremergencies, live by them andthey will help yQU Gr the nextQccupants Qf that aircraft stayalive. If there is any dGubtabQut Qther limitatiGns, fQrinstance maximum continuQuspower, consult the -1 fQr theaircraft that you are flying.

REFERENCES:

AIRCRAFT POWER PLANTS,Northrop Aeronautical Institute, pp106-108, 117.

FAA Manual 107, pp 24-27, 30-34.TF1 4131 Power and Octane.USAF TO 06-5-4, pp 38, 77, 84-90.


27/40

L SSON

CAPTAIN F R E H A RTglanced casually a t the skyas he left base operations withhis copilot, Lieutenant K e nHarris. Quite as casually, his

mind's eye took in the surro.unding scene. Azure bo wlof sky overhead, flecked withcottony puffs of clo.uds. Sundrenched asphalt apron, do.ttedwith white - rimmed tie - downrings. Everything endo.rsed thecarbo.n copy of the weatherclearance in his hand. Shouldbe a fine flight to Randall AirForce Base.

M/ Sgt Charles E uchanan

P a r k e d a short distanceaway, silver no.se aslant a t thesky, was the Go.oney in whichthey were to make the trip.Squatting alongside the plane,

with a well-used B-4 bag andan o.live drab overnight kitbetween them, were their two

hitch-hiker passengers. Hartglanced a t his manifest: a Lieutenant Richard M Sloan andM/Sgt Terry Lewis.

Both passengers c a m e totheir feet and saluted smartlya t the approach of the pilots.Hart returned their salute and

SILK

mentally no.ted their appearance. The sergeant was of ar a t h e r stalwart build, withlarge, blue - veined hands, anda s i g h t y furro.wed face .

Hash marks and overseas barsgleamed o n his left sleeve. TheLieutenant, shorter, and inclined to be slender, was in his

Th1 s article is reprinted fromThe MATS Flyer. M / Sgt Buch-anan was assigned to the 1709thT echnical Training S q u a d ro nPalm Beach AFB Fla. when thisarticle was written.

25


28/40

APRIL 1960

late twenties. A double row ofribbons denoted that he hadbeen around the service quitea few years.

Captain Hart slid his ownB-4 bag into the plane, andpulled himself up the steps,

holding his fresh uniform ona hanger in his left hand. Hehooked it onto a nearby strapand turned to help his copilotup the steps. On the floor, justinside the door, was a pile ofparachutes. For a single instant he hesitated with thethought of briefing his passengers on the use of a chute, butchuckled to himself a t the obvious uselessness of such astep. The sergeant was an oldtimer - probably with manyhours in the blue throughoutthe world, and the lieutenantwas no novice, either.

He leaned against gravity,trudging up the steep, inclinedfloor of the '47, and made hisway to the cockpit, turning toedge into the seat past the aislepedestal. His copilot closed thedoor and then followed him tothe adjoining seat. After he

had gotten the safe signalfrom the crew chief standingwith the fire bottle outside,Harris reached up and fingeredthe starting switch. There wasa familiar hum of the starter,and he heard a whir, a cough,and then a roar of both enginesin turn. The plane trembledslightly and incessantly as theinstrument pointers felt for

operating conditions.Harris picked up the mike,

asked for takeoff instructionsfrom the tower, and signaledfor the crew chief to pull thechocks. Hart p a I m e d boththrottles forward and felt theplane jounce ahead slowly inresponse. They edged past acrew of three perched on an

aero stand b e s i d e an uncowled C-45, on past two grimy-

26

coveralled mechanics on an approaching yellow tug, and slowly swung onto the assigned runway. Captain Hart smiled reminiscently as he watched a B-25lumber into the air off the farend of the runway.

They pivoted into place andran the checklist. EverythingO K He worked controls backand forward, sharp right andleft. A call to the tower gavethem full possession of the runway.

He leaned slightly to lock thetail wheel, throttled forwardand felt the tautness of thecontrols as wind and plane engaged in the takeoff embrace.The reeling belt of runwayplunged suddenly away and thewhite specked blue of the skysaturated the V of the windshield. With a left 90 and aright 45, he felt slowly for altitude, and picked up his heading. A couple of deft fingermovements turned it over tthe auto-pilot.

Both pilots settled back tothe pattern of extended flight,so identical to many before it,

routinely checking instrumentsand idly watching the landscape crawl by below.

A tedious hour passed. Another thirty minutes. The moments seemed geared to thesluggishly m v i n g landscapestretched below. Then suddenly the fire detector for the leftengine glowed red. Hart darteda quick glance toward the indicated engine, and his heartbounced into , his throat at thesight of wavering petals of yellow flame licking out of thecowling. We're on fire on No.1, Ken, he shouted.

Quickly he feathered theprop, cut the switch and fuel tothe left engine, then reacheddown, opened the fire extinquisher cover, an d . flipped theselector to left. He pulled

savagely on the cable release.The yellow serpents of firemerely wavered slightly butcontinued to spill out of thecowling.

It 's no good, he yelled.We'll have to leave her. Hit

the alarm bell.Hart squirmed out of his

seat, following the stern-facedcopilot. As they mil de theirway out of the cockpit, he washorrified to find his passengersstill seated.

What you waiting for? heblurted, We're on fire. Got toleave it.

The sergeant's apologetic expression as he stood up wouldhave been ludicrous in anothersituation. I don't know how tput a chute on, sir. And i t waslike the dread voice of doomwhen he heard the lieutenantecho, I don't either.

Fred Hart felt a block of icejell in his mid-section. Over hisshoulder he could see that theleft wing was a seething massof flames. Heavy black smokewas boiling out of the cockpit,and snaking back to where they

were. The acrid fumes were beginning to claw a t his parchedthroat.

I t seemed incredible, and yethere were two grown men, anofficer and non - commissionedofficer, obviously holding responsible positions in the AirForce, who did not know how toput on chutes. Younger men,he would have surely briefed.

How much time hem um b l ed desperately to thesmoke - wavering top of thep I n e , and then resolutionnudged by desperation filledhim. Ken, you help the lieutenant, and I'll help the sergeant.

D s h i n g to the rear, hedragged the chutes back to thecenter, and together, feverishly, both pilots worked to un-


29/40

hrough his extended legs he could s th ground rushingtoward him

tangle the harness of chutes,slide them onto their passengers, and tighten the straps.

Now go, he yelled.a n i c wrestled with their

self - control as they b o t hgrabbed their own, shoulderedinto

them ,and tightened

thestraps. The cabin was full ofboiling black smoke as theysprinted for the door. Behindthem, the c c k p i t was anorange 0 v e n of shimmeringflames. I t was a miracle thatthe pitching, lumbering planewas still in flight. He saw hiscopilot go out the door and hurtle backward and downwardand, squaring his shoulders, heIunged into space.

Outside, the wind tore a thim, but he felt motionlesslypasted between the earth andsky. He seemed barely out thedoor when there were violenteruptions of flame, and theplane, trailing smoke, hingedits left wing upward and begana crazy spiral toward the earth.

Thank God, H a r t felt,rather than said. Dimly, as he

fell, he was aware of threemushrooms of silk which indicated the others were safe. Hepulled savagely at his ripcordwith both hands and felt thechute's r eassu r in g whippingand billow. The opening joltpained him slightly, but i t wasunnoticed in the rush of reliefthrough his bosom.

Through his extended leg s,he could see the earth rushingup toward him. Twisting in hisharness, he watched the planestrike the ground, flash orangeand yellow flame, and thenthrow up boiling ovals of blacksmoke. He was mutely thankful that there was no humanhabitation below.

His stomach contorted violently as he thought how closethey had come to being in thatblazing holocaust. And thendeep within him he heard thevoice of his sub-conscious, thatinsolent, tactless companion ofsolitary vigils and dark moments.

Well, mister, it taunted,that was close. Matter of fact,

you and all those people entrusted to you are jus t plainlucky to be alive. It's no creditto you that fate chose to grantyou t h o s e precious seconds.That was a sad performance ofduty. Don't you know it's apilot's duty to brief his passengers?

But they I 0 0 k like oldtimers, Fred protested, I always brief the kids, but how'dI know people - like tha t didn'tknow a simple thing like how toput on a chute.

Didn't it ever occur to you,mister, that there are hundredsof jobs in the Air Force thatdon't require a minute of flight.Probably that sergeant is inFood Service, and most likelythe lieutenant is a desk jockey.

Anyway, the plane was inperfect shape. I t pre-flightedright on the money.

That's a lame excuse. Tomake an internal combustionengine in the first place, youharness the ingredients of hell.And even the best servicedplane sometimes loses the in

fernal battle, for reasons thatno man can say. Who knows ifthat flaming pile down therewas human error or physicalcaprice. The parachute wasmade in acknowledgement tothe Big Variable, and no pilothas a right to accept anyone'ssafety in his hands withoutmaking sure they have an advantage of unquestioned knowledge of its life - saving techniques.

The brown and green carpetof the earth thrus t up swiftlyand rammed against his feet,sending pain through his legsas he tumbled. But i t was agood, solid, reassuring feeling,and Captain Fred Hart knewthat he would n e v e r againthrottle an aircraft into the

blue without heeding thiscrucial lesson-in-silk.

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W EATHER, r u s t y shortfield technique, low time intype or model, flying skill satrophied through months ofdesk-bound duty - these holdno terror for the aviator whois straining to attain annualminimums. Compuls ions of

flight pay and career seem tourge the last hour rush in theface of many hazards. Annualflight minimums, designed t om a i n t a i n flying prof iciency ,s o m e t i m e s boomerang in todemonstrations of the need forproficiency.

One Army Aviator con s idered himself very lucky to beassigned a three-hour

Army Aviation Digest - Apr 1960

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Transcript of Army Aviation Digest - Apr 1960