DOCSLIB.ORG

Of Stall Characteristics

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
Of Stall Characteristics 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
Load more

Recommended publications
  • CANARD.WING LIFT INTERFERENCE RELATED to MANEUVERING AIRCRAFT at SUBSONIC SPEEDS by Blair B
    https://ntrs.nasa.gov/search.jsp?R=19740003706 2020-03-23T12:22:11+00:00Z NASA TECHNICAL NASA TM X-2897 MEMORANDUM CO CN| I X CANARD.WING LIFT INTERFERENCE RELATED TO MANEUVERING AIRCRAFT AT SUBSONIC SPEEDS by Blair B. Gloss and Linwood W. McKmney Langley Research Center Hampton, Va. 23665 NATIONAL AERONAUTICS AND SPACE ADMINISTRATION • WASHINGTON, D. C. • DECEMBER 1973 1.. Report No. 2. Government Accession No. 3. Recipient's Catalog No. NASA TM X-2897 4. Title and Subtitle 5. Report Date CANARD-WING LIFT INTERFERENCE RELATED TO December 1973 MANEUVERING AIRCRAFT AT SUBSONIC SPEEDS 6. Performing Organization Code 7. Author(s) 8. Performing Organization Report No. L-9096 Blair B. Gloss and Linwood W. McKinney 10. Work Unit No. 9. Performing Organization Name and Address • 760-67-01-01 NASA Langley Research Center 11. Contract or Grant No. Hampton, Va. 23665 13. Type of Report and Period Covered 12. Sponsoring Agency Name and Address Technical Memorandum National Aeronautics and Space Administration 14. Sponsoring Agency Code Washington , D . C . 20546 15. Supplementary Notes 16. Abstract An investigation was conducted at Mach numbers of 0.7 and 0.9 to determine the lift interference effect of canard location on wing planforms typical of maneuvering fighter con- figurations. The canard had an exposed area of 16.0 percent of the wing reference area and was located in the plane of the wing or in a position 18.5 percent of the wing mean geometric chord above the wing plane. In addition, the canard could be located at two longitudinal stations.
    [Show full text]
  • CHAPTER TWO - Static Aeroelasticity – Unswept Wing Structural Loads and Performance 21 2.1 Background
    Static aeroelasticity – structural loads and performance CHAPTER TWO - Static Aeroelasticity – Unswept wing structural loads and performance 21 2.1 Background ........................................................................................................................... 21 2.1.2 Scope and purpose ....................................................................................................................... 21 2.1.2 The structures enterprise and its relation to aeroelasticity ............................................................ 22 2.1.3 The evolution of aircraft wing structures-form follows function ................................................ 24 2.2 Analytical modeling............................................................................................................... 30 2.2.1 The typical section, the flying door and Rayleigh-Ritz idealizations ................................................ 31 2.2.2 – Functional diagrams and operators – modeling the aeroelastic feedback process ....................... 33 2.3 Matrix structural analysis – stiffness matrices and strain energy .......................................... 34 2.4 An example - Construction of a structural stiffness matrix – the shear center concept ........ 38 2.5 Subsonic aerodynamics - fundamentals ................................................................................ 40 2.5.1 Reference points – the center of pressure..................................................................................... 44 2.5.2 A different
    [Show full text]
  • Helicopter Dynamics Concerning Retreating Blade Stall on a Coaxial Helicopter
    Helicopter Dynamics Concerning Retreating Blade Stall on a Coaxial Helicopter A project presented to The Faculty of the Department of Aerospace Engineering San José State University In partial fulfillment of the requirements for the degree Master of Science in Aerospace Engineering by Aaron Ford May 2019 approved by Prof. Jeanine Hunter Faculty Advisor © 2019 Aaron Ford ALL RIGHTS RESERVED ABSTRACT Helicopter Dynamics Concerning Retreating Blade Stall on a Coaxial Helicopter by Aaron Ford A model of helicopter blade flapping dynamics is created to determine the occurrence of retreating blade stall on a coaxial helicopter with pusher-propeller in straight and level flight. Equations of motion are developed, and blade element theory is utilized to evaluate the appropriate aerodynamics. Modelling of the blade flapping behavior is verified against benchmark data and then used to determine the angle of attack distribution about the rotor disk for standard helicopter configurations utilizing both hinged and hingeless rotor blades. Modelling of the coaxial configuration with the pusher-prop in straight and level flight is then considered. An approach was taken that minimizes the angle of attack and generation of lift on the advancing side while minimizing them on the retreating side of the rotor disk. The resulting asymmetric lift distribution is compensated for by using both counter-rotating rotor disks to maximize lift on their respective advancing sides and reduce drag on their respective retreating sides. The result is an elimination of retreating blade stall in the coaxial and pusher-propeller configuration. Finally, an assessment of the lift capability of the configuration at both sea level and at “high and hot” conditions were made.
    [Show full text]
  • Vertical Motion Simulator Experiment on Stall Recovery Guidance
    NASA/TP{2017{219733 Vertical Motion Simulator Experiment on Stall Recovery Guidance Stefan Schuet National Aeronautics and Space Administration Thomas Lombaerts Stinger Ghaffarian Technologies, Inc. Vahram Stepanyan Universities Space Research Association John Kaneshige, Kimberlee Shish, Peter Robinson National Aeronautics and Space Administration Gordon Hardy Retired Research Test Pilot Science Applications International Corporation October 2017 NASA STI Program. in Profile Since its founding, NASA has been dedicated • CONFERENCE PUBLICATION. to the advancement of aeronautics and space Collected papers from scientific and science. The NASA scientific and technical technical conferences, symposia, seminars, information (STI) program plays a key part or other meetings sponsored or in helping NASA maintain this important co-sponsored by NASA. role. • SPECIAL PUBLICATION. Scientific, The NASA STI Program operates under the technical, or historical information from auspices of the Agency Chief Information NASA programs, projects, and missions, Officer. It collects, organizes, provides for often concerned with subjects having archiving, and disseminates NASA's STI. substantial public interest. The NASA STI Program provides access to the NASA Aeronautics and Space Database • TECHNICAL TRANSLATION. English- and its public interface, the NASA Technical language translations of foreign scientific Report Server, thus providing one of the and technical material pertinent to largest collection of aeronautical and space NASA's mission. science STI in the world. Results are Specialized services also include organizing published in both non-NASA channels and and publishing research results, distributing by NASA in the NASA STI Report Series, specialized research announcements and which includes the following report types: feeds, providing information desk and • TECHNICAL PUBLICATION. Reports of personal search support, and enabling data completed research or a major significant exchange services.
    [Show full text]
  • Airplane Icing
    Federal Aviation Administration Airplane Icing Accidents That Shaped Our Safety Regulations Presented to: AE598 UW Aerospace Engineering Colloquium By: Don Stimson, Federal Aviation Administration Topics Icing Basics Certification Requirements Ice Protection Systems Some Icing Generalizations Notable Accidents/Resulting Safety Actions Readings – For More Information AE598 UW Aerospace Engineering Colloquium Federal Aviation 2 March 10, 2014 Administration Icing Basics How does icing occur? Cold object (airplane surface) Supercooled water drops Water drops in a liquid state below the freezing point Most often in stratiform and cumuliform clouds The airplane surface provides a place for the supercooled water drops to crystalize and form ice AE598 UW Aerospace Engineering Colloquium Federal Aviation 3 March 10, 2014 Administration Icing Basics Important Parameters Atmosphere Liquid Water Content and Size of Cloud Drop Size and Distribution Temperature Airplane Collection Efficiency Speed/Configuration/Temperature AE598 UW Aerospace Engineering Colloquium Federal Aviation 4 March 10, 2014 Administration Icing Basics Cloud Characteristics Liquid water content is generally a function of temperature and drop size The colder the cloud, the more ice crystals predominate rather than supercooled water Highest water content near 0º C; below -40º C there is negligible water content Larger drops tend to precipitate out, so liquid water content tends to be greater at smaller drop sizes The average liquid water content decreases with horizontal
    [Show full text]
  • CAP High Ground 18.03
    The High Ground A Newsletter From Wyoming Wing Standards/Evaluation 15 March, 2018 Hot Topics Pilot Proficiency Profiles… The New Reality! With the implementation of CAPR 70-1 Flight Management, the Air Force came out with new requirements for documentation of training sorties. The AF now requires us to document what is planned, and what we actually accomplished during that sortie, per the Pilot Prof iciency Profile. We are required to accomplish all of the REQUIRED items listed in the PPP Checklist. We have to document each item and upload/note supporting documentation, or document why we did not accomplish the required item. Please review the preamble of the Pilot Proficiency Profiles (first page) and the specific Profile which you are planning on flying. Unfortunately, we can’t “just wing it” anymore. (Sigh) This ain’t my idea, this is from “On High”. Pilot Proficiency Profiles To review, the Pilot Proficiency Profiles, dated 01 January 2018, have changes. Best to print out a copy and keep it handy while operating under any one of these Profiles. And the Profiles are now to be documented in the “Profile Used” in WMIRS as P#, i.e. Profile number 1 would be entered as “P1”. Note that each Profile has a header which dictates the PIC qualifications to operate under that Profile. Read these before you attempt to fly the Profile. Now the BIG CHANGE is in the details of each Profile, what we are expected to do, and what we have to document for each Pilot Proficiency Profile sortie. Each PPP has in its description “Routine” and “Required” Items.
    [Show full text]
  • Teng Tianhang 201606 MAS T
    Representative Post-Stall Modeling of T-tailed Regional Jets and Turboprops for Upset Recovery Training by Tianhang Teng A thesis submitted in conformity with the requirements for the degree of Master of Applied Science Graduate Department of Aerospace Science and Engineering University of Toronto c Copyright 2016 by Tianhang Teng Abstract Representative Post-Stall Modeling of T-tailed Regional Jets and Turboprops for Upset Recovery Training Tianhang Teng Master of Applied Science Graduate Department of Aerospace Science and Engineering University of Toronto 2016 Loss-of-control resulting from airplane upset is a leading cause of worldwide commer- cial aircraft accidents. In order to provide pilots with sufficient stall recovery training using ground simulators, flight models will need to be improved. In this thesis, a methodology for generating a generic representative post-stall aircraft model is developed. Current type specific post-stall models are too expensive to generate, and are not practical for routine training. The representative model offers a much cheaper way to train crew for upset conditions, at the same time providing sufficiently realistic cues seen in an upset condition. The methodology provides a foundation for generating full scale representative models using wind tunnel data and physics-based approaches. An example of applying the methodology to predict stall regime aircraft behavior is provided for one aerodynamic coefficient. ii Acknowledgements First, I would like to express my sincere gratitude to my thesis supervisor Professor Peter Grant for the continuous support of my MASc study and related research, for his patience, motivation, and immense knowledge. His guidance helped me throughout the entire research and writing portions of this thesis.
    [Show full text]
  • Stall Warnings in High Capacity Aircraft: the Australian Context 2008 to 2012
    Stall warnings in high capacityInsert document aircraft: title The Australian context Location2008 to 2012 | Date ATSB Transport Safety Report InvestigationResearch [InsertAviation Mode] Research Occurrence Report Investigation XX-YYYY-####AR-2012-172 Final – 1 November 2013 Publishing information Published by: Australian Transport Safety Bureau Postal address: PO Box 967, Civic Square ACT 2608 Office: 62 Northbourne Avenue Canberra, Australian Capital Territory 2601 Telephone: 1800 020 616, from overseas +61 2 6257 4150 (24 hours) Accident and incident notification: 1800 011 034 (24 hours) Facsimile: 02 6247 3117, from overseas +61 2 6247 3117 Email: [email protected] Internet: www.atsb.gov.au © Commonwealth of Australia 2013 Ownership of intellectual property rights in this publication Unless otherwise noted, copyright (and any other intellectual property rights, if any) in this publication is owned by the Commonwealth of Australia. Creative Commons licence With the exception of the Coat of Arms, ATSB logo, and photos and graphics in which a third party holds copyright, this publication is licensed under a Creative Commons Attribution 3.0 Australia licence. Creative Commons Attribution 3.0 Australia Licence is a standard form license agreement that allows you to copy, distribute, transmit and adapt this publication provided that you attribute the work. The ATSB’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Source: Australian Transport Safety Bureau Copyright in material obtained from other agencies, private individuals or organisations, belongs to those agencies, individuals or organisations. Where you want to use their material you will need to contact them directly.
    [Show full text]
  • SM11188 Standard Modification Page : 1 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson
    Mod No. SM11188 Standard Modification Page : 1 of 6 Issue 1 Compiled : S Brown Approved : F Donaldson TITLE : Main Wing Trailing Edge Flow Straighteners AIRCRAFT TYPE : Vari-Eze Mod Type: Retro-fit 1. Introduction The Rutan Aircraft Factory approved the (later to be mandatory) installation of leading edge vortilons on all Vari-Ezes in the October 1984 edition of the Canard Pusher ( CP 42 pages 5/6) to improve the swept main wing stall margins, increase visibility over the nose on final approach and enable reduced approach speeds without the risk of low speed wing rock or deep stall. The vortilons generate vortices over the main wing at high angles of attack that reduce lift-losing span-wise flow. There is negligible speed or drag penalty Flow straighteners positioned on the trailing edge of the swept main wing further reduce span wise flow at high angles of attack. It has been demonstrated that the addition of trailing edge flow straighteners enable the wing to produce more lift at a given angle of attack enabling lower approach speeds with no loss of view over the nose. The result is a reduced sink rate for a given airspeed and an increased margin between main wing and canard stall speeds. 2. Parts List Qty Part No. Description Source 2 SM11188-1 Outboard Fence Manufacture 2 SM11188-2 Middle Fence Manufacture 2 SM11188-3 Inboard Fence Manufacture White RTV Silicone Hardware store Flocked Cotton / BID / Aircraft Spruce Epoxy Resin List of related drawings / photos Drawing No. Title / Description Issue SM11188-D1 Drawing of Flow Straighteners dimensions SM11188-D2 Drawing of installation on main wing and fitting detail SM11188-D3 Photograph of Gary Hertzler’s fences installation on N99VE 3.
    [Show full text]
  • REPORT No. 201
    REPORT No. 201 THE EFFECTS OF -SHIELDING THE THIS OF AIRFOILS By ELLIOTT G. IWD Langley Memorial Aeronautical Laboratory 3-M REPORT No. 201 THE EFFECTS OF SHIELDING THE TIPS OF AIRFOILS By ELLIOTT G. REID SUMMARY Tests have recently been made at Langley Memorial Aeronautical Laboratory to ascertain whet her the aerodynamic characteristics of an airfoil might be subst antiall-j -impro~ed by imposing certain limitations upon the airflow about its tips. AU of the moditied forms were slightly inferior to the plain airfoil at small lift coefikients; however, by mounting thin plates, in planes perpendicular to the span, at the W@ tips, the characteristics were impro~ed throughout the range above three-tenths of the masimum lift coefficient. With this form of limitation the detrimental effect was slight; at the higher lift .—— coefEcients there resulted a eorsiderable reduction of induced drag and, consequently, of pow-er required for sustentation. The s16pe of the curve of lift ~erws angle of attack was increased. OUTLINE OF TESTS These tests wwe directed to-ward the disco~ery of some economical means of increasing the “ effecti~e aspect ratio” of an airfol As it. is recognized that the induced drag of an airfoiI is inversely proportional to its aspect ratio and that elimination of the transverse velocity, components of the air.tlow about a wing reproduces, in effecfi, the conditions which wouId exist with Mnite aspect ratio, it was planned to investigate the effects of elimination of a portion of the transverse flow by. fln.ite barriers at. the tips and ‘also by the production of an aer~- dcynamic counterforee, in lieu of the com- straints:-by the localization of severe washout at the tzps.
    [Show full text]
  • May 1983 Issue of Soaring Magazine
    Cambridge Introduces The New M KIV NA V Used by winners at the: 15M French Nationals U.S. 15M Nationals U.S. Open Nationals British Open Nationals Cambridge is pleased to announce the Check These Features: MKIV NAV, the latest addition to the successful M KIV System. Digital Final Glide Computer with • "During Glide" update capability The MKIV NAV, by utilizing the latest Micro­ • Wind Computation capability computer and LCD technology, combines in • Distance-to-go Readout a single package a Speed Director, a • Altitude required Readout 4-Function Audio, a digital Averager, and an • Thermalling during final glide capability advanced, digital Final Glide Computer. Speed Director with The MKIV NAV is designed to operate with the MKIV Variometer. It will also function • Own LCD "bar-graph" display with a Standard Cambridge Variometer. • No effect on Variometer • No CRUISE/CLIMB switching The MKIV NAV is the single largest invest­ ment made by Cambridge in state-of-the-art Digital 20 second Averager with own Readout technology and represents our commitment Relative Variometer option to keeping the U.S. in the forefront of soar­ ing instrumentation. 4·Function Audio Altitude Compensation Cambridge Aero Instruments, Inc. Microcomputer and Custom LCD technology 300 Sweetwater Ave. Bedford, MA 01730 Single, compact package, fits 80mm (31/8") Tel. (617) 275·0889; TWX# 710·326·7588 opening Mastercharge and Visa accepted BUSINESS. MEMBER G !TORGLIDING The JOURNAL of the SOARING SOCIETYof AMERICA Volume 47 • Number 5 • May 1983 6 THE 1983 SSA INTERNATIONAL The Soaring Society of America is a nonprofit SOARING CONVENTION organization of enthusiasts who seek to foster and promote all phases of gliding and soaring on a national and international basis.
    [Show full text]
  • Design of a Transonic Wing with an Adaptive Morphing Trailing Edge Via Aerostructural Optimization
    Design of a Transonic Wing with an Adaptive Morphing Trailing Edge via Aerostructural Optimization David A. Burdettea, Joaquim R. R. A. Martinsa,∗ a University of Michigan, Department of Aerospace Engineering Abstract Novel aircraft configurations and technologies like adaptive morphing trailing edges offer the potential to improve the fuel efficiency of commercial transport aircraft. To accurately quantify the benefits of morphing wing technology for commercial transport aircraft, high-fidelity design optimization that considers both aerodynamic and structural design with a large number of design vari- ables is required. To address this need, we use high-fidelity aerostructural that enables the detailed optimization of wing shape and sizing using hundreds of de- sign variables. We perform a number of multipoint aerostructural optimizations to demonstrate the performance benefits offered by morphing technology and identify how those benefits are enabled. In a comparison of optimizations con- sidering seven flight conditions, the addition of a morphing trailing edge device along the aft 40% of the wing can reduce cruise fuel burn by more than 5%. A large portion of fuel burn reduction due to morphing trailing edges results from a significant reduction in structural weight, enabled by adaptive maneuver load alleviation. We also show that a smaller morphing device along the aft 30% of the wing produces nearly as much fuel burn reduction as the larger morphing device, and that morphing technology is particularly effective for high aspect ratio wings. Keywords: Morphing, Adaptive compliant trailing edge, Wing design, Aerostructural optimization, Common Research Model ∗Corresponding author Preprint submitted to Elsevier August 8, 2018 1. Introduction Increased awareness of environmental concerns and fluctuations in fuel prices in recent years have led the aircraft manufacturing industry to push for improved aircraft fuel efficiency.
    [Show full text]