Summary of Low-Speed Airfoil Data - UIUC Applied Aerodynamics

445 Pages·1998·12.45 MB·English

Summary of Low-Speed Airfoil Data
Christopher A. Lyon, Andy P. Broeren, Philippe Gigu`ere,
Ashok Gopalarathnam, and Michael S. Selig
Volume 3
Summary of Low-Speed Airfoil Data
Volume 3
About the Authors
Christopher A. Lyon received his B.S. in Aerospace Engineering from the University of
Notre Dame in the spring of 1995. Upon his arrival at UIUC the following fall, he joined the
LSATs team as project coordinator and began pursuing his M.S. degree. Fueled by a desire
to design high performance, yet exotic R/C aircraft, he has researched topics ranging from
boundary-layer trips to tailless aircraft. Additionally, he has been involved in R/C aircraft
for 14 years, and recently was a design team member and pilot of UIUC’s winning entry in
the 1996–97 AIAA Student Design/Build/Fly Competition.
Andy P. Broeren received his B.S. in Mechanical Engineering from the Milwaukee School
of Engineering in 1993. Several months after beginning his graduate study in mechanical
engineering at UIUC, he joined Michael Selig and Jim Guglielmo in their efforts to establish
the UIUC LSATs. Andy has completed his M.S. degree and is presently working toward a
Ph.D. with dissertation research in unsteady airfoil aerodynamics. He has participated for
several years in the Society of Automotive Engineers (SAE) Aero-Design competition and
most recently was team leader and design team member of UIUC’s winning entry in the
1996–97 AIAA Student Design/Build/Fly Competition.
Philippe Gigue`re has been involved with the UIUC LSATs since his arrival on campus
in September 1994. Since then, he has been working towards a Ph.D. degree with research
in horizontal-axis wind turbine blade design and optimization. Other research areas of
interest include: low-speed airfoil aerodynamics, wind-tunnel boundary corrections, and
optimization methods. Originally from Qu´ebec City, Canada, Philippe Gigu`ere performed
his previous studies at McGill University (Bachelor degree in Mechanical Engineering–
1992) and Universit´e Laval (Master of Science degree and Teaching Diploma–1994). He
participated in the SAE Aero-Design competition from 1991–94 and flies full-scale gliders.
Ashok Gopalarathnam received his Bachelor of Technology (1989) and Master of Science
(1993) in Aerospace Engineering from the Indian Institute of Technology, Madras. During
1991–94, he worked as a Scientist/Engineer at the National Aerospace Laboratories in India
as a member of the Hansa-2 design team (a two-seat all-composite light airplane which first
flew in 1993). Since 1995, he has been working towards his Ph.D. at UIUC and has been
involved with the UIUC LSATs. His research interests include low-speed aerodynamics,
aircraft design, and design methodologies. He flies both full-scale sailplanes and general
aviation airplanes and was a design team member of UIUC’s winning entry in the 1996–97
AIAA Student Design/Build/Fly Competition.
Dr. Michael S. Selig, an accomplished applied aerodynamicist and airfoil designer, is
an Assistant Professor of Aeronautical and Astronautical Engineering at the University of
Illinois at Urbana-Champaign. He received his B.S. from the University of Illinois in 1984,
his M.S.E. from Princeton University in 1988, and his Ph.D. from the Pennsylvania State
Universityin1992. Hiscurrentresearchareasincludelow-speedaerodynamics, airfoildesign,
wind energy, and flight simulation. He teaches courses in applied aerodynamics and aircraft
design. He has been active in R/C soaring for over 20 years.
Christopher A. Lyon
Andy P. Broeren
Philippe Gigu`ere
Ashok Gopalarathnam
Michael S. Selig
Department of Aeronautical and Astronautical Engineering
University of Illinois at Urbana-Champaign
Summary of Low-Speed Airfoil Data
Volume 3
SoarTech Publications
Virginia Beach, Virginia
SoarTech Publications
1504 N. Horseshoe Circle
Virginia Beach, Virginia 23451, USA
Copyright (cid:1)c 1997 by
Christopher A. Lyon, Andy P. Broeren, Philippe Gigu`ere, Ashok Gopalarathnam,
and Michael S. Selig
All rights reserved.
The cover photograph shows a close-up of surface oil flow visualization results for the
E374 (B) with a 0.030-in. thick zigzag trip located at x/c = 30% and Re = 200,000. As
air moves over the model, fluorescent oil applied to the surface of the model flows in the
direction of the local flow velocity. In the process, oil streaks are formed which allow the
direction and nature of the local flow (laminar, turbulent, separated) to be identified. For
similar flow visualization results, the reader is referred to Chapters 3 and 6.
First Printing, December 1997
Lyon, Christopher Alan
Summary of Low-Speed Airfoil Data – Volume 3 / by Christopher A. Lyon, Andy
P. Broeren, Philippe Gigu`ere, Ashok Gopalarathnam, and Michael S. Selig.
Includes bibliographical references.
1. Aerofoils (Airfoils). 2. Aerodynamics. 3. Airplanes—Models.
I. Model Aviation. II. Title
ISBN 0-9646747-3-4
Contents
Preface . . . . . . . . . . . . . . . . . . . . . . . . . . . iii
Acknowledgments . . . . . . . . . . . . . . . . . . . . . . . v
List of Figures . . . . . . . . . . . . . . . . . . . . . . . . ix
List of Tables . . . . . . . . . . . . . . . . . . . . . . . . xix
List of Symbols/Acronyms . . . . . . . . . . . . . . . . . . xxi
1 The Airfoils Tested . . . . . . . . . . . . . . . . . . . . . 1
2 Measurement Techniques . . . . . . . . . . . . . . . . . . . 3
2.1 Lift Balance . . . . . . . . . . . . . . . . . . . . . . 3
2.2 Moment Balance . . . . . . . . . . . . . . . . . . . . 4
2.3 Tunnel Speed Controller . . . . . . . . . . . . . . . . 5
2.4 Data Acquisition and Reduction . . . . . . . . . . . . . 5
3 Data Validation . . . . . . . . . . . . . . . . . . . . . . . 9
3.1 Drag Data . . . . . . . . . . . . . . . . . . . . . . . 9
3.2 Lift Data . . . . . . . . . . . . . . . . . . . . . . . 12
3.3 Moment Data . . . . . . . . . . . . . . . . . . . . . 14
3.4 Flow Features . . . . . . . . . . . . . . . . . . . . 14
3.5 Data Validation Summary . . . . . . . . . . . . . . . 17
4 Summary of Airfoil Data . . . . . . . . . . . . . . . . . . 19
4.1 Airfoils for Sailplanes . . . . . . . . . . . . . . . . 24
4.2 Airfoils for Powered Aircraft . . . . . . . . . . . . 30
4.2.1 Symmetric Airfoils . . . . . . . . . . . . . . . 31
4.2.2 Semi-Symmetric Airfoils . . . . . . . . . . . . . 33
4.2.3 Flat-Bottom Airfoils . . . . . . . . . . . . . . 36
4.3 Airfoils for Small Wind Turbines . . . . . . . . . . . 37
4.4 Airfoils for Special Interest . . . . . . . . . . . . . 43
5 Airfoil Profiles and Performance Plots . . . . . . . . . . 47
6 Boundary-Layer Trips . . . . . . . . . . . . . . . . . . . 331
6.1 Trip Locations and Conventions . . . . . . . . . . . . 332
6.2 Two-Dimensional Trips . . . . . . . . . . . . . . . . 333
6.2.1 Effect of Trip Width . . . . . . . . . . . . . . 336
6.2.2 Effect of Trip Location . . . . . . . . . . . . . 336
6.3 Three-Dimensional Trips . . . . . . . . . . . . . . . . 338
ii Summary of Low-Speed Airfoil Data
References . . . . . . . . . . . . . . . . . . . . . . . . . 343
Glossary . . . . . . . . . . . . . . . . . . . . . . . . . . 347
Appendix A Supplemental Inviscid Velocity Distributions . . . 351
Appendix B Tabulated Airfoil Coordinates . . . . . . . . . . 361
Appendix C Tabulated Polar Data . . . . . . . . . . . . . . 391
Appendix D Airfoil Data Distribution . . . . . . . . . . . . 413
Appendix E UIUC Low-Speed Airfoil Tests Manifesto . . . . . 415
Preface
Summary of Low-Speed Airfoil Data – Volume 3 is the third installment in a series
of books documenting the ongoing work of the University of Illinois at Urbana-
Champaign Low-Speed Airfoil Tests (UIUC LSATs). Being an out-growth of the
1
work documented in Airfoils at Low Speeds (SoarTech 8) performed by Michael
Selig, John Donovan, and David Fraser while at Princeton, the project’s purpose
remains the same — to develop and test airfoils for low-speed aircraft, in particular,
R/C model airplanes. Since the time that SoarTech 8 was published, however, much
of the results have found wider application on unmanned aerial vehicles (UAVs),
low-speed propellers, and wind turbines.
Despite a growing interest from people in areas outside R/C aircraft, this effort
has continued largely through the generous support of model-aviation enthusiasts.
Without their contributions, encouragement, and enthusiasm this work would not
have been possible or nearly as rewarding. A complete listing of the program
contributors is given in the Acknowledgments section.
The current UIUC LSATs team consists of Michael Selig (Asst. Prof.) as project
advisor, Chris Lyon (M.S.) as project coordinator, Andy Broeren (Ph.D.), Philippe
Gigu`ere (Ph.D.), and Ashok Gopalarathnam (Ph.D.). This group, together with the
help of Christopher J. Fisichella (Ph.D.), required two and a half months in mid-
March 1996 (Spring ‘96 installment) and one and a half months in early-April 1997
(Spring ’97 installment) to acquire the data presented in this book.
The Book and Its Organization
Readers familiar with the format of previous volumes should find Volume 3 easy to
navigate. As before, Chapter 1 illustrates the airfoils tested and briefly addresses
the flap and boundary-layer trip configurations used. Chapter 2 documents changes
made to the testing facility since Volume 2, and Chapter 3 provides a comparison
between UIUC LSATs data and data obtained by NASA Langley in the Low-
Turbulence Pressure Tunnel (LTPT). Chapter 4 discusses the airfoils tested, and
Chapter 5 contains the corresponding performance plots, including the new pitching-
moment data. Included in Chapter 6, and also new to the Summary of Low-Speed
Airfoil Data series, is an extensive discussion of boundary-layer trip performance.
Following Chapter 6 is a glossary of terms the LSATs team feels are important.
Finally, Appendix A includes inviscid velocity distributions for many of the airfoils
presented in Volume 2, Appendices B and C list tabulated airfoil coordinates and
drag polars respectively, Appendix D discusses how the data presented in this book
can be obtained on diskette and any restrictions regarding its use, and Appendix E
contains the UIUC LSATs Manifesto outlining the scope and purpose of this work.
iv Summary of Low-Speed Airfoil Data
Acknowledgments
Without the support and enthusiasm provided by many people, the UIUC LSATs
would be a shadow of its present self. To each of these people we are indebted.
In particular, we are especially grateful to the organizations, clubs, businesses,
individuals, and t-shirt patrons who provided monetary support for equipment and
graduate student salaries. Listed below are those who provided this support on which
we so dearly depend. (Shown in parentheses is the fraction of total support received
from each category.)
Organizations (7%): British Association of Radio Control Soarers (BARCS)
andAcademyofModelAeronautics(withspecialappreciationtoJerryRouillard).
2
Businesses (42%): B Streamlines (Bill & Bunny Kulhman), Design and
Manufacturing Ltd. (Jack Spitz and Ernest Trent, Jr.), Dynamic Modeling
(Don Edberg), Griffith University, Landing Products (Fred Burgdorf), Muncie
Pawn Brokers (Bill Greene), R.C. Hanger (Johnny Berlin), Sailplane Modeler
(Wil Byers), R/C Soaring Digest (Jerry & Judy Slates), SoarTech Publications
(H.A. Stokely), Top Flight (Don Anderson), and Traplet Publications Limited
(Dave Jones).
Model Clubs (4%): Baltimore Area Soaring Society, Clent Soaring Association
(England), Portland Area Sailplane Society, Round Valley Radio Control Club,
Tidewater Model Soaring Society, and Tri-County Aero Club.
Individuals (41%): Anonymous, Mike D. Adkins, David K. Anderson, Arnold
Angelici, Jim Armstrong*, Thomas Atwood, Bruce Baker*, Gary S. Baldwin*,
Charles Baltzer, Keith Beggin*, Robert Bender*, Bernard Biales, C. Blake*, Eric
L. Blanke, Paul Bly*, Charles L. Botzko*, Arthur Boysen*, Andy Broeren, Joyce
C. Broeren*, Chris Burns*, Myron Cagen*, Bruce Carmichael, Bill Cavanaugh,
Robert A. Champine*, Erich Chase*, Ben Clerx*, John L. Cranmer, Jr.*, Michael
J. Cresanta, Michael D. Denton*, Alfred J. DeRenzis*, Michael W. Derr*, Thom
Earle*, Waldron E. Ehrlich*, Stephen J. Fauble*, William S. Friedlander, Dave
Garwood*, Laurent Gasser, B.I. Gaston*, Rolf Girsberger, William M. Green*,
Charles Griswold, John Haren*, James B. Halbert*, Chuck Hallum*, Bob Harold,
Don Harris*, Raymond E. Hatton, Brian L. Henry*, George B. Herider*,
Bruce Herider*, Takashi Hoshizaki, Lester Hulett, Alfred C. Inman, John
S. Jensen*, Giraud Julien, Gen Katayama*, Daniel Kong*, John F. Krohn*,
Michael Lachowski*, Ben Lawless*, Lydia Lazurenko, Nhan T. Le*, Laurent
Lebrun*, Dr. Robert M. Livin, Charles R. Lohre, Phillip Lontz, Eric H. Loos*,
Steve Lucke, Fred Mallett, Lubos Mitas*, Andy Mitas*, Edward Mitchell*,
O.G. Morris, Gilbert C. Morris, Steve Neu*, Nick Neve*, John D. Newell, MD,
Kevin Noland, Ted Off, Paul H. Ortman, Scott Pack*, Jean Pailet, Phil Pearson,