LONGITUDINAL AERODYNAMIC CHARACTERISTICS OF AN AIRCRAFT MODEL WITH AND WITHOUT WINGLET

7/28/2019 LONGITUDINAL AERODYNAMIC CHARACTERISTICS OF AN AIRCRAFT MODEL WITH AND WITHOUT WINGLET

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UNIVERSITI PUTRA MALAYSIA

LONGITUDINAL AERODYNAMIC CHARACTERISTICS OF AN

AIRCRAFT MODEL WITH AND WITHOUT WINGLET

MD. ALTAB HOSSAIN.

FK 2005 19


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LONGITUDINAL AERODYNAMIC CHARACTERISTICS OF AN AIRCRAFTMODEL WITH AND WITHOUT WINGLET

BYMD. ALTAB HOSSAIN

Thesis Submitted to the School of Graduate Studies, Universiti Putra Malaysia,in Fulfilment of the Requirements for the Degree of Master of Science.October2005


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DEDICATION

Dedicate this thesis

To his teachers;

To his parents Md. Golbar Hossain and Mrs. Aleya KhatoonAnd

To the memory of his Late Grandfather who had devoted his love and guiding of thefamily


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Abstract of thesis presented to Senate of the Universiti Putra Malaysia in fulfilm entof the requirements for the d egree of Master of Scien ce

LONGITUDINAL AEROD YNAM IC CHARACTERISTICS OF AN A IRCRAFTMODEL WITH AND W ITHOUT WINGLET

MD. ALTAB HOSSAINOctober 2005

Chairman: Associate Professor Prithvi Raj Arora, PhDFaculty: Engineering

The measurement of aerodynamic forces and mom ents acting on an aircraft model isimportant for the development of wind tunnel measurement technology. T he primarypurpose of wind tunnel measurements over the model for the forces and moments isto predict the performance of the full-scale vehicle. Force measurement techniquesin wind tunnel testing are necessary for determining a variety of aerodynamicperformance parameters. Fo r three-dimensional aircraft models, forces and m om entsare usually measured directly using a balance system. The balance mechanicallyseparates the total aerodynamic load on a model into its six aerodynamiccomponents. Tw o fundamental types of balances, external and internal balances, a reused today. External balances carry the loads outside the tunnel before they aremeasured and internal balances wh ich fit in the model and are arranged to send dataout through electrical wires.


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In this research work, six-component external balance is commissioned and thecalibration has been thoroughly checked and the detailed procedure of measurementof aerodynamic forces is recommended. A set of winglet has been designed for theexisting aircraft model at the Aerodynamics laboratory of the AerospaceEngineering Department, UPM. Further the aerodynamic forces are measured on theaircraft model having a rectangular wing with and without winglet attached to themodel. Tests have been carried out on the aircraft model with and without winglet atthe Reynolds numbers 170,000, 210,000 and 250,000. Th e experimental resultsshow that lift curve slope increases by 1-6% with the addition of certain wingletconfigurations and at the same time the drag decreases by 20-28% as compared tothose for the aircraft model without winglet for the maximum Reynolds numberconsidered in the present study.


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Abstrak tesis yang dikemukakan kepada Senat Universiti Putra Malaysiasebagai memenuhi sebahagian keperluan untuk ijazah Master Sains

PENYELIDIKAN TERHA DAP C IRI-CIRI AERODINAMIK PADA ARAHMENDATAR K E ATAS M ODEL PESAWAT BER "WINGLET" DANTANPA "WINGLET"Oleh

MD. ALTAB HOSSAINOktober 2005

Pengerusi: Profesor Madya Prithvi Ra j Arora, PhDFakulti: Kejuruteraan

Pengukuran daya dan momen aerodinamik yang bertindak ke atas sesebuah modelpesawat adalah penting dalam pembangunan teknologi pergukuran untuk bagiterowong angin. Tujuan utama pengukuran daya dan momen tersebut terhadapmodel ialah untuk meramal prestasi saiz sebenar kenderaan yang diuji. Teknikpengukuran adalah perlu dalam menentukan pelbagai parameter prestasiaerodinamik. Untuk model sebuah pesawat tiga-dimensi daya dan momen diukurterns menggunakan debuah sistem imbangan. Sistem, imbangan mernisahkan dayapaduan keatas models kepada enam komponen aerodinamik. Dua jenis azastimbangan yang digunakan setakat ini iaitu timbangan luar dan timbangan dalam.Timbangan dalam menahan beban diluar terowong sebelum diukur dan timbangandalam yang mana terpasang di dalam model dan diatur untuk mengirim data melaluiwayar elecktrik.


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Dalam kajian ini, enam komponen imbangan luaran diuji dan tentu ukur diperiksadan prosedur terperinci mengenai pengukuran daya-daya aerodinarnik dicadangkan.Satu set "winglet" telah direka untuk model pesawat sedia ada di makmalAerodinamik Jabatan Kejuruteraan Aeroangkasa, UPM. Seterusnya, daya-dayaaerodinamik terhadap model pesawat yang mempunyai sayap empat segi tepatdengan "winglet" dan tanpa "winglet" telah dianalise. Ujian telah dijalanka ke atasmodel pesawat dingan "winglet" dan tanpa "winglet" pada nombor "Reynolds"170000, 2 1000 0 dan 250000. Keputusan eksperimen menunjukkan bahawakecerunan lengkuk daya angkat meningkat 1-6% dengan menggunakan konfigurasi"winglet" tertentu dan dalam masa yang sama daya seret berkurangan sebangak 20-28% debgan membandingkan keputusan model pesawat tanpa "winglet" untuknobm or "Reynolds" m aksim um yang dipertimbangkan dalam kajian ini.


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ACKNOWLEDGEMENTS

First of all my thanks and gratitude to Allah for the completion of this researchsuccessfully. I would like to express my heart-felt thanks and sincere gratitude to mysupervisor Associate Professor Dr. Prithvi Raj Arora and the members of the-supervisory committee, Dr. Prasetyo Edi, Dr. Abdul Aziz Jaafar and AssociateProfessor Dr. Thamir Sabir Younis. Their doors were always open for me to get help

and suggestions whenever needed. It is beyond doubt that without their assistanceand kind support, it was impossible for me to complete this research work.

I am grateful to Dr. Ahmad Samsuri Mokhtar, Head of the Aerospace Department,Faculty of Engineering for his encouragement and support to complete this researchwork. My appreciation also goes to all of my teachers especially to Prof. Ir. Dr.ShahNor Basri, Associate Professor Mohd. Ramly Mohd. Ajir, Dr. El-Sadiq Mahdi,Dr. Moharnmad Salim, Lt. Kol. (B) Mohs. Tarmizi Ahmad, and En. MoharnmadNizam Filipski Abdullah for their support and co-operation.

I acknowledge the Ministry of Science, Technology and Environment (MOSTE),Malaysia and to the Universiti Putra Malaysia (UPM) for the research grants to carryout the research work. I am also thankful to Mr. Rofiee Mat, Mr. Daeng, Mr. AhmadSaifol Abu Samah, Mr. Irfan, Mr. Thariq, Mr.Azmin, Mr. Catur, Mr. Suresh Jakob,Mr. Fuaad Hasan, and Mr. Noorfaizal for their all kinds of technical advices andkind help.

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I feel proud to express that all of my family members including my parents,grandmother, brothers, uncles and aunts gave me help, guidance and inspirationthrough out this work. Their sacrifice and love made this thesis a great success in mycarrier.

Last but not the least, my appreciation and thanks to all around my surroundingsespecially to Dr. Zahangir Alam and Mrs. Zahangir, Dr. Md. Liakot Ali, Dr. Md.Abul Hossen Mollah, Dr. Md. Aminul Haque, Mr. Ataur Rahman, Mr. Ahsan Ali,

Mr. Anayet Karim and Mrs. Anayet, Mr. Jakir Hossen, Mr. A.K.M. Parvez Iqbal,Mr. Mannan Sarkar, my cousin Dr. Joynul Abedin, my friends Md. ShafiquzzamanSiddiquee, Hena, Md. Sohel Mustafiz, Mrs. Shamima Kabir, Md. Ibrahim Mehedi,Saadat, Obayed and all my country people in UPM, for their help and co-operationduring my struggle in the MSc. pursuit.

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I certify that an Examination Committee met on 19" Oktober 2005 to conduct thefinal examination of Md. Altab Hossain on his Master of Science thesis entitled"Longitudinal Aerodynamic Characteristics of an Aircraft Model with and withoutWinglet" in accordance with Universiti Pertanian Malaysia (Higher Degree) Act1980 and Universiti Pertanian Malaysia (Higher Degree) Regulations 1981. TheCommittee recommends that the candidate be awarded the relevant degree.Members of the Examination Committee are as follows:

Mohd. Ramly M ohd. Ajir, PhDAssociate ProfessorFaculty of EngineeringUniversiti Putra Malaysia(Chairman)ShahNor Basri, PhDProfessorFaculty of EngineeringUniversiti Putra Malaysia(Internal Examiner)Ahmad Samsu ri M okhtar, PhDLecturerFaculty of EngineeringUniversiti Putra Malaysia(Internal Examiner)Waqar Asrar, PhDProfessorKulliyyah of EngineeringInternational Islamic University Malaysia(External Examiner)

School of Graduate ~b d i e sUniversiti Putra Malaysia


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This thesis submitted to the Senate of Universiti Putra Malaysia and has beenaccepted as fulfilment of the requirement for the degree of Master of Science. Themembers of the Supervisory Committee are as follows:

Prithvi Raj Arora, PhDAssociate ProfessorFaculty of EngineeringUniversiti Putra Malaysia(Chairman)Abdul Aziz Jaafar, PhD -LecturerFaculty of EngineeringUniversiti Putra Malaysia(Member)PrasetyoEdi, PhDLecturerFaculty of EngineeringUniversiti Pu tra Malaysia(Member)Thamir Sabir Younis, PhDAssociate ProfessorFaculty of EngineeringUniversiti Putra Malaysia(Member)

AINI IDERIS, PhDProfessor/DeanSchool of Graduate StudiesUniversiti Putra MalaysiaDate: 8 DEC 2005


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DECLARATION

I hereby declare that the thesis is based on my original work except for quotationsand citations, which have b een duly acknowledged. I also declare that it h as not beenpreviously or concurrently submitted for any other degree at UPM or otherinstitutions.

MD. ALTAB HOSSAINDate: ig l lf105


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TABLE OF CONTENTS

PagesDEDICATIONABSTRACTABSTRAKACKNOWLEDGEMENTSAPPROVALDECLARATIONLIST OF TABLESLIST OF FIGURESLIST OF ABBREVATIONSLIST OF SYMBOLSCHAPTER

INTRODUCTION1.1 Background1.2 Problem Statement1.3 Objectives of the Study1.4 Organization of the ThesisLITERATURE REVIEW2.1 Background2.2 Induced drag and winglets

2.2.1 Coefficient of Induced Drag2.2.2 Reduction of Induced DragApplication of Winglets2.3.1 Winglet for Sailplane2.3.2 Winglet for Roadable Aircraft2.3.3 Winglet for Hydrodynamic Surfaces2.3.4 Winglet for Wind Turbines2.3.5 Winglet for Flat Plate ModelWing Tip Devices2.4.1 Hoerner Tips2.4.2 Wing Endplates2.4.3 The Winglet

2.5 Wing tip modifications for performance improvement2.5.1 Background2.5.2 Conventional or Blended Winglet2.5.3 Spiroid Technology2.5.4 Wing with Multiple Winglets

2.6 Summary of the Literature Review2.7 Conclusions of the Literature Review

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METHODOLOGY3.1 Synopsis3.2 Model Details

3.2.1 Wing Details3.2.2 Winglet Design3.2.3 Drawing of the Winglet3.2.4 Description of Six-Component External Balance

3.3 Calibration of External Balance3.3.1 Procedure of Calibration

3.4 Wind Tunnel Testing3.4.1 Description of Wind Tunnel3.4.2 Basic Components of Low Subsonic Wind Tunnel

3.4.2.1 Test Section3.4.2.2 Contraction Cone3.4.2.3 Settling Chamber and Screens3.4.2.4 Diffuser3.4.2.5 Driving Unit3.4.2.6 Specification of the Wind Tunnel

3.4.3 Test Section Flow Calibration3.4.3.1 Free Stream Velocity Calibration3.4.3.2 Flow Uniformity

3.4.4 Starting Procedure3.4.5 Testing Procedure3.4.6 Specimen Calculation3.4.7 Testing of the Aircraft Model with Elliptical and Circular

Winglet3.4.8 Verification of Wind Tunnel Measurement

3.4.8.1 Specimen Calculation3.5 Project Structure Flow ChartRESULTS AND DISCUSSIONS4.1 Results and Discussions

4.1.1 Coefficient of Lift4.1.2 Coefficient of Drag4.1.3 Coefficient of Pitching Moment4.1.4 LiftLDrag Ratio

4.2 Effect of Winglet Geometry4.2.1 Coefficient of Lift4.2.2 Coefficient of Drag4.2.3 LiftLDrag Ratio

CONCLUSIONS AND RECO MMENDATIONS5.1 Conclusions5.2 Recommendations for Future Research Works

REFERENCESAPPENDICESRIODATA OF THE AUTHOR

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LISTOF TABLES

Table3.1: Load locations at different steps3.2: Equivalent forces and moments for different load conditions3.3: Sensor readings corresponding to different load conditions-3.4: Inverse of coefficient matrix (Calibration Matrix)3.5: Calibration matrix supplied with six component external balance

3.6: Percentage of Error

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3.7: Wind tunnel external balance software velocity (mls) for correspondingHz 463.8: Digital manometer reading (Dynamic pressure) for correspondingHz 473.9: Digital manometer reading (Velocity) for correspondingHz3.10: Manometer tube reading (Dynamic pressure) for correspondingHz3.1 1: Manometer tube reading (Velocity) for correspondingHz3.12: Wind tunnel external balance software velocity and Digital manometer

velocity for corresponding Hz3.13: Dynamic pressure reading (Pa) at different locations of YZ-plane3.14: Dynamic pressure variations from the mean (%) at different locations of

YZ-plane 543.15: Free stream velocity and corresponding Reynolds and Mach number3.16: Winglet Configurations3.17: Drag force for corresponding free stream velocity3.18: Free stream velocity and corresponding Reynolds and Mach number3.19: Calculated drag coefficients and Reynolds number3.20: Experimental drag coefficients data and Reynolds number4.1: Aerodynamic forces acting on the aircraft model without winglet

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4.2: Aerodynamic forces acting on the aircraft model with elliptical winglet ofconfiguration 1

4.3: Aerodynamic forces acting on the aircraft model with elliptical winglet ofconfiguration 2 73

4.4: Aerodynamic forces acting on the aircraft model with circular winglet ofconfiguration 1 74

4.5: Aerodynamic forces acting on the aircraft model with circular winglet ofconfiguration 2

4.6: Lift coefficient, Drag coefficient, and Pitching moment coefficient data for theaircraft model without winglet 76

4.7: Lift coefficient, Drag coefficient, and Pitching moment coefficient data for theaircraft model with elliptical winglet of configuration 1 774.8: Lift coefficient, Drag coefficient, and Pitching moment coefficient data for the

aircraft model with elliptical winglet of configuration 2 784.9: Lift coefficient, Drag coefficient, and Pitching moment coefficient data for the

aircraft model with circular winglet of configuration 1 794.10: Lift coefficient, Drag coefficient, and Pitching moment coefficient data for the

aircraft model with circular winglet of configuration 2 804.11 Lift coefficients experimental data4.12: Drag coefficients experimental data4.13: Pitching moment coefficients experimental data4.14: LiftDrag Ratio experimental data4.15: Lift curve slope (per radian) for all the configurations
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LIST OF FIGURES

Figures Pages

Airplane Configuration with WingletsKC-135 Winglet Flight Tests at Dryden Flight Research CentreFormation of Wingtip VorticesInduced Drag on the AerofoilTypical Winglet ApplicationView of the Pegasus in flightHoerner Tips and Round Tips before TestingConventional and Blended WingletGeometric Characteristics of the Wing PlanfonnNACA 65 & ?8 AerofoilFull Model Balance Assembly under Test Section

3.4 TOP view of Calibration Rig3.5 Open Loop Low Speed Wind Tunnel (OLWT- 1000)3.6: Free stream velocity curves.3.7: Free stream velocity curves for calibration3.8: Schematic view of wind tunnel test section3.9: Dynamic pressure variations from the mean (%) in the test section3.10: Drag Coefficients for sphere as a function of the Reynolds number4.1 Lift Coefficients for the Aircraft Model4.2 Drag Coefficients for the Aircraft Model4.3 Pitching Moment Coefficients for the Aircraft Model

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ABBREVIATIONS

AFFDLBBJCNCDOCLaRCNACANASAOLWTPSURPM

Air Force Flight Dynamics LaboratoryBoeing Business JetComputer Numerically ControlledDirect Operating CostLangely Research CenterNational Advisory Committee for AeronauticsNational Aeronautics and Space AdministrationOpen Loop Wind TunnelPennsylvania State UniversityRevolutions Per Minute

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LIST OF SYMBOLS

Wing spanChord lengthAngle-of-attackDrag forceInduced dragLift forcePitching momentNewtonNewton meterAir densityPlan surface or reference areaAspect RatioEfficiency factorConstantViscosity of airAmbient temperatureKelvinFree stream velocityReynolds numberMach NumberSpeed of SoundGas constant

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Dynamic pressureDrag coefficientCoefficient of Induced dragLift coefficientPitching moment coefficientLiftJDragLoad No. 1Load No. 2Load No. 3Load No. 4Load No. 5Load No. 6Signal MatrixCoefficient MatrixLoad Matrix


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CHAPTER 1INTRODUCTION

Background

One of the primary barriers limiting the performance of aircraft is the drag that the-aircraft produces. This drag stems from the vortices shed by an aircraft's wings,which causes the local relative wind downw ard (an effect known as dow nwash) and

generate a component of the local lift force in the direction of the free stream. Thestrength of this induced drag is proportional to the spacing and radii of thesevortices. By designing win gs, which force the vortices farther apart and at the sam etime create vortices with larger core radii, it may significantly reduce th e amoun t ofdrag the aircraft induces. Airplanes which experience less drag require less powerand therefore less fuel to f ly an arbitrary distance, thus making flight, commercial,more efficient and less costly. One promising drag reduction device is the winglet.For a number of years many investigations have been carried out to prove thepossible benefits of modifying wing tip flow. Tip devices have become a populartechnique to increase the aerodynamic performances of lifting wings. The ideabehind all the devices described is to diffuse the strong vortices released at the tipand optimise the span wise lift distribution, while maintaining the additionalmoments on the wing within certain limits (Filippone, 2004). Winglets haveincreasingly becom e a popular method of altering the trailing tip vortex system froman aircraft wing and thus improve the aircraft performance. A winglet is a deviceused to improve the efficiency of aircraft by lowering the lift-induced drag causedby wingtip vortices. A winglet provides an innovative method of achieving the


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vortex arrangement described above. The concept involves constructing wingswhose tips are small extension in the form of a smaller aerofoil section placed at anyangle, as shown in Figure 1. .

Figure 1.1 Airplane Configuration with Winglets (Boeing Commercial Airplanes,Washington).

Because the vortices shed by the wing are strongest at the tips of the wing, theaddition of wing tip surfaces can reduce and diffuse the strength of these vortices,thus reducing the overall vortex drag of the aircraft (Asselin, 1997). Two pairs ofwinglets are used with the aircraft model existing in Aerodynamics Laboratory ofAerospace Engineering Department, Universiti Putra Malaysia. The longitudinalaerodynamic characteristics of aircraft model with two-winglet configuration havebeen the subject of this research work.


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Problem Statement

Th e airfoil is the heart o f an airplane it affects th e cruise speed, takeoff and lan dingdistances, stall speed, handling qualities (specially near the stall), and overallaerodynamic efficiency during all phases of flight. When wing is generating lift, ithas a reduced pressure on the upper surface and an increased pressure on the lower-surface. For a wing of finite span, the air on the upper surface flows inward and airbelow the under-surface flows outward. For this reason there is a continual spilling

of the air round the wing tip from the bottom surface of the wing to the uppersurface. These tw o aifflows meet at the trailing edge and c ause w ing-tip vortices. Ifthere is a wing of infinite aspect ratio, the air flows over the wing surface withoutany inward or outward deflection, and therefore no wing-tip vortices, no induceddrag. But such a thing is impossible in practical flight, and for this reason theeffective aspect ratio is increased as large as is practicable by using winglet. Theextension of wingspan permit the lowering of drag but this comes at a cost ofincreasing the strength of the wing and hence its weight. This establishes the needfor the winglet. Winglets work by increasing the aspect ratio of a wing withoutadding greatly to the structural stress and hence necessary w eight of its structure.

Th e small extension at the wing tip is called winglet and is placed at any angle to theexisting wing surface so that the rotating vortex flow at the wing tip creates a liftforce o n the winglet that has a forward com ponent. This forward component of thelift force reduces the total wing drag. The idea behind the winglet is to produce aflow field that interacts with that of the main wing to reduce the amount of span


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wise flow. That is, the span wise induced velocities from the winglet oppose andthereby cancel those generated by the main wing.The purpose of this investigation is to study the behaviour of an added winglet ofvaried geometries to a NACA 65-3-218 rectangular wing as a part of an existingaircraft model.

1.3 Objectives of the studyThe main objectives of this research work are1. To comp are the calibration matrix with calibration matrix provided with the six-

component external balance as supplied by the m anufacturer.2. To design and fabricate a set of winglet for the existing aircraft model at the

Aerodynamics Laboratory of the Aerospace Engineering Department, UPM.3. To measure the lift and drag forces and pitching moment of the aircraft model

having a rectangular wing with and without winglet attached to the model byusing six-component external balance at the Aerodynamics Laboratory of theAerospace Engineering Department, UP M .

4. To com pare the experimental lift force, drag force and pitching moment for themodified wing of an existing aircraft model with an elliptical and a circularwinglets of given aspect ratio with the results obtained through the unmodifiedaircraft mod el.

1.4 Organisation of the ThesisThe dissertation is divided into five chapters. In chapter one, the requirements ofwinglet in the A erospace industry for the aircraft model are discussed. This chapter

LONGITUDINAL AERODYNAMIC CHARACTERISTICS OF AN AIRCRAFT MODEL WITH AND WITHOUT WINGLET

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