NASACONTRACTOR REPORT A DESIGNSUMMARY OF STALLCHARACTERISTICS OF STRAIGHT WING AIRCRAFT by M. A. McVeigb md E. Kisielowski Prepared by DYNASCIENCESCORPORATION SCIENTIFICSYSTEMS DIVISION Blue Bell, Pa. for Langley Research Center NATIONALAERONAUTICS AND SPACE ADMINISTRATION WASHINGTON, D. C. JUNE 1971 -__- TECH LIBRARY KAFB, NM "" ~~ ~ ~~___ ~___. "" . ~ -~ ~ 00607b3 1. Report No. 2. GovernmentAccession No. 3. Recipient. rormluy I.u. NASA CR-1646 - -~ ~~ ~~~ -~ 4. Title andsubtitle ~ I 5. ReportDate A DESIGN SUMMARY OF STALL CHARAC!iTBISTICS OF STRAIGHT WING AIRCRAFT June lg7' 6. Performing Organization Code ~ ~~ .~ ~ .. ~ . ~-- -~ 7. Author(s) 8. Performing Organization Report No. M. A. McVeigh and E. Kisielowski DCR-705 ~ ..~"" ~ ". .. 10. Work Unit No. 9. Performing Organization Name and Address 126-13-10-06-23 DynasciencesCorporation I 11. Contract or Grant No. Scientific SystemsDivision I BlueBell, Pennsylvania NASl-8389 13. Type of Reportand Period Covered ~ ~~ 12. SponsoringAgency Name and Address Contractor Report NATIOW AERONAUTICS AND SPACEADMINISTRATION 14. SponsoringAgency Code WASHINGTON, D. C. 20546 "" " - ~______~ .. .- - . .. ~~ .~ 1-I 15. SupplementaryNotes ""___ ._. ." . - ~. 16. Abstract A method of wing design using lifting line theory described in NACA Reports 865 and 1090 has beencomputerized and used tostudy the parameters which affect wing stall characteristics. The results of thestudy and the computerprogramaredescribed. The effects of airfoil section variations,Reynolds number, aspect ratio, wing twist ad taper ratio are presented in design chart form. - _i .- ~. - - ~ - 17. KeyWords (Suggested by Author(s) ) 18. Distribution Statement Subsonic Wing Design Unclassified - Unlimited Strip Theory Computer Program ~.-. 19. Security Classif. (of this report) Unclassified I . Unclassified 226 ". " ~- For sale by the NationalTechnical Information Service, Springfield, Virginia 22151 -. - SUMMARY Presented in this report is a comprehensivereview of the existing tech.nica1 literature and a design summary of stall ch.aracteristics applicable to light straigh.t wing aircraft. These characteristics are obtained with th.e aid of a digital computerprogram which. utilizes the most up to date analytical methodsemploying lifting line theoryand the available exper- imental test datafor wing sectioncharacteristics. The computer results are presented in th.e formof stall ch.arts suitable for preliminarydesign purposes. Based on th.e extensiveparametric studycovering a total of 331 different aircraft configurations, it canbe concluded that in modern airplane design satisfactory stalling characteristics can be readily built in with no apprecia- bleloss in airplane performance or handling qualities. A proper combination ofwing taper, twist andtype of airfoil sections with. minorpost-design fixes, if required, can in most cases provide satisfactory wing stall characteristics. iii I - FOREWORD This reportpresents a design summary of stall ch.aracter- istics ofstraigh.t wing aircraft. Th.e workwas performed by th.e Scientific SystemsDivision (SSD) of the DynasciencesCorDoration, Blue Bell,Pennsylvania, for the NationalAeronautics and Snace Administration (NASA), LangleyResearch Center, Hampton, Virginia,under contract number NAS 1-8389during the periodfrom July 1968 through SeDtember 1969. Th.e NASA technicalrepresentatives were Mr. Robert T. Taylor and Mr. William J. Alford, Jr. The contributions of the NASA technicalpersonnel to this work are gratefully acknowledged. Acknowledgement is also extended to NASA computerpersonnel, especially Mrs. Belinda Adams, for their supportin this program. Messrs. James C. Sivells and :Hartley A. Soul; were mecia1 technical consultants on this Drojectand Mr. Ron Anton was computer consultant. V l- CONTENTS Page SUMMARY.................................... iii FOREWORD ................................... V LIST OF ILLUSTRATIONS...................... viii LIST OFTABLES. ............................ xi LISTOF SYMBOLS. ........................... xiii SECTION 1 INTRODUCTION. .............................. 1 SECTION 2 BASICCONSIDERATIONS OF AIRPLANE STAUING....... ............................ 4 SECTION 3 THEORETICAL ANALYSI S. ...................... 21 SECTION 4 COMPUTER PROGRAM... ........................ 42 SECTION 5 PARAMETRIC INVESTIGATION.... ............... 75 131 SECTION 6 SCALE MODEL WIND TUNNEL TESTING. ........... SECTION 7 DESIGN PROCEDURES. ......................... 136 SECTION 8 CONCLUSIONS AND RECOMMENDATIONS.. .......... 142 SECTION 9 REFERENCES.. ............................... 144 APPENDIXINTERNALA LISTING OF THE COMPUTER PROGRAM...... .............................. 149 vii II I ILLUSTRATIONS Figure Page 1 RepresentativeLift Curve(Reproduced from Reference 13) ..................................... 10 2 Th.e Low-Speed StallingCharacteristics ofAirfoil Sections Correlated With. Reynolds Number and theUpper-Surface Ordinates of theAirfoil Sections at the 0.0125-Chord Station.. ..................... 12 Wing Leading Edge Mofifications for Controlling Wing Stall ....................................... 20 Definition ofParameters for Transformation of Wing-Body Combinat ion. ............................ 26 Typical Load Distributions for Obtaining Factors forAltering Two-Dimensional Data.............. ... 37 Illustration of Meth.od for Correcting Two- DimensionalSection Data ......................... 39 Extrapolations of Lift CurveSlopes at Low Reynolds Number .................................. 51 Variation of SectionLift-Curve Slope with Thick- ness-ChordRatio at ConstantReynolds Number NACA 644 Sections ................................ 54 9 Corrected LiftCurves for NACA 64-421 Airfoil at Low Reynolds Numbers .......................... 55 10 Methodof Tabulation of Section Ch.aracteristics . 57 11 Sch.ematic Representation of SectionData Storage in the Computer .................................. 59 12 Nomenclature for DevelopingInterpolation Formulae 61 13 ComputerProgram Block Diagram ................... 62 1.4 SchematicRepresentation of the Computer Input Cards ............................................ 63 15 Experimentaland Calculated Characteristics for a Wing of AspectRatio 8.04 ...................... 68 viii li- - J Figure Page 16 Experimental and Calculated Characteristics for a Wing of Aspect Ratio10.05 ............... 70 17 Experimental and Calculated Characteristics for a Wingof Aspect Ratio 12.06 ............... 72 18 Experimental and Calculated Characteristics for Wingwith. 60% Flap; Aspect Ratio 9.02; Taper Ratio 0.4; Washout 2O .......................... 74 19 Typical Lift Distributions Along Wing Span..... 81 20 Variation of Clmax with Reynolds Number and Thickness-Chord Ratio .......................... 83 21 Variation of CLmax with Reynolds Number and Taper Ratio ........................................... 86 22 Effect of Aspect Ratio on Stall Margin Distribution ................................... 88 23 Effect of Aspect Ratio on Wing Stall Pattern....91 24 Effect of Aspect Ratio and Taper Ratio'Lmax. on . 94 25 Increment of Induced-Drag Coefficient Due to Washout, 230 Series Airfoil Section............ 98 26 Effect of Root Thickness-Chord Ratio on Stall Margin Distribution ............................ 101 27 Effect of Root Thickness-Chord Ratio on Wing Stall Boundaries ...............................104 28 Effect of Root Th,ickness-Chord RatioCLmax on . , . 107 29 Effect of Tip Thickness-Chord Ratio on Stall Margin Distribution ............................ 111 30 Effect of Tip Thickness-Chord Ratio on'Lmax ... 114 31 Effect of Reynolds Number on Stall Margin Distribution ................................... 117 32 Effect of Reynolds Number on Wing Stall Pattern ........................................ 120 ix Figure Page 33Effect of Reynolds Number on Chax............... 123 34 Effect of Wing Camber on Stall Margin Distribution. .................................... 127 35 Effect ofFuselage ............................... 128 36 Effectof the Spanofa 20% Chord SplitFlap on the Wing Stalling Characteristics. ............ 130 37 Variationof WingMaximum LiftCoefficient with. Stall Speed ................................. 138 X TABLES Tables Page I Airfoil Section Data Available for Use with the Computer Program ............................ 56 I1 Typical Computer Output.. ....................... 65 I11 Summary of Configurations Studied ............... 76 xi SYMBOLS A non-dimensionalfuselage semil5eigh.t A' fuselage semih.eight, f t . Ai wing aspect ratio, An coefficientsin trigonometric series a non-dimensionalaverage distance of point on wingfrom fuselage cross-section focI-1 al averagedistance of point onwing from fuselage cross-sectionfocii, ft. sectionlift-curve slope, per degree non-dimensionalfuselage semiwidth fuselage semiwidth, ft. wingspan, ft. flapspan, ft. total wing drag coefficient,- D qs wing profile drag coefficient, qs Di wing induced drag coefficient,-Di qs wing lift coefficient, -L CL qs M wing pitching moment coefficient, total section drag coefficient section induced drag coefficient section profile drag coefficient section lift coefficient, -I qc design lift coefficient two-dimensional, uncorrected value of lift coefficient maximum section lift coefficient maximum two-dimensional section lift coefficient section lift coefficient at end of flap section lift coefficient forth.at part of lift distribution involving no discontinuity in angle of attack section lift coefficient for partof c12 lift distribution due to discontinuity in angle of attack section