Modeling Flight: The Role of Dynamically Scaled Free-Flight Models in Supportof NASA's Aerospace Programs

2010·6 MB·English

by  Joseph Chambers

MODELING
FLIGHT
The Role of Dynamically Scaled
Free-Flight Models in Support
of NASA’s Aerospace Programs
Joseph Chambers
MODELING
�
FLIGHT
The Role of Dynamically Scaled
Free-Flight Models in Support
of NASA’s Aerospace Programs
Joseph R. Chambers
Library of Congress Cataloging-in-Publication Data
Chambers, Joseph R.
Modeling flight : the role of dynamically scaled free-flight models in support of
NASA’s aerospace programs / by Joseph R. Chambers.

p. cm.

“NASA SP 2009-575.”

Includes bibliographical references and index.
1. Airplanes--Models--United States--Testing. 2. Wind tunnel models--United
States--Testing. 3. Aeronautics--Research--United States--Methodology. 4. United
States. National Aeronautics and Space Administration. I. Title.

TL567.M6C48 2010

629.101’1--dc22

2009048942
TABLE OF CONTENTS
Acknowledgements....................................................................................................................vii

Introduction...................................................................................................................................1

Background...................................................................................................................................7

Objectives................................................................................................................................ 7

Role.of.Free-Flight.Testing.......................................................................................................8

Principles.of.Dynamic.Scaling..................................................................................................9

Rigid-Body.Dynamic.Models..................................................................................................11

Incompressible.Flow...............................................................................................................11

Compressible.Flow.................................................................................................................14

Limitations.and.Interpretation.of.Results................................................................................15

Historical.Development.by.the.NACA.and.NASA....................................................................17

Spin.Research.Facilities.........................................................................................................18

The.Langley.20-Foot.Spin.Tunnel..........................................................................................19

Wind.Tunnel.Free-Flight.Research.Facilities..........................................................................22

The.Langley.12-Foot.Free-Flight.Tunnel................................................................................24.

The.Langley.Full-Scale.Tunnel...............................................................................................26.

The.Ames.Hypervelocity.Free-Fight.Facilities........................................................................29

The.Ames.40-.by.80-Foot.Tunnel...........................................................................................32

Outdoor.Free-Flight.Facilities.and.Ranges.............................................................................33

Langley.Unpowered.Drop.Models..........................................................................................33

TABLE OF CONTENTS iii
Dryden.Unpowered.Drop.Models........................................................................................... 37

Langley.Powered.Free-Flight.Models..................................................................................... 39

Langley.Control.Line.Facility.................................................................................................. 40

Ames.Powered.Free-Flight.Models........................................................................................ 41

Dryden.Powered.Free-Flight.Models...................................................................................... 41

Wallops.Rocket-Boosted.Models............................................................................................ 42

Selected.Applications................................................................................................................ 43.

Dynamic.Stability.and.Control.................................................................................................. 47.

Low-Speed.Research.............................................................................................................. 47

High-Speed.Research:.Rocket-Propelled.Models................................................................... 50

Supersonic.Tests.at.Ames....................................................................................................... 52

Unconventional.Configurations............................................................................................... 52

The.Early.Days........................................................................................................................ 53

V/STOL.Configurations........................................................................................................... 58

Parawing.Configurations......................................................................................................... 65

Variable.Geometry................................................................................................................... 68

Space.Capsules...................................................................................................................... 73

Reentry.Vehicles.and.Lifting.Bodies........................................................................................ 75

Supersonic.Transports............................................................................................................ 79

Vehicle/Store.Separation......................................................................................................... 80

Advanced.Civil.Aircraft............................................................................................................ 83

Wake.Vortex.Hazard............................................................................................................... 84

iv MODELING FLIGHT
Towed.Vehicles.......................................................................................................................85

Concept.Demonstrators..........................................................................................................86

Summary................................................................................................................................88

Flight.at.High.Angles.of.Attack.................................................................................................89

Fighters...................................................................................................................................94

Summary...............................................................................................................................102

Spinning.and.Spin.Recovery...................................................................................................103

Background..........................................................................................................................103

Military.Configurations..........................................................................................................105

General-Aviation.Configurations...........................................................................................116

Skewed.Wing.Configuration.................................................................................................117

Summary...............................................................................................................................117

Spin.Entry.and.Poststall.Motions...........................................................................................119

Spin.Entry.............................................................................................................................119

Military.Configurations..........................................................................................................120

General-Aviation.Configurations...........................................................................................131

Jet.Transport.Upset.Recovery..............................................................................................135

Tumbling...............................................................................................................................136

Other.Studies........................................................................................................................137

Summary...............................................................................................................................138

Associated.Test.Techniques.................................................................................................. 139

Aerodynamic.Data................................................................................................................139

TABLE OF CONTENTS v
Static.Tests........................................................................................................................... 140

Forced-Oscillation.Tests....................................................................................................... 141

Free-to-Roll.Tests................................................................................................................. 142

Rotary-Balance.Tests........................................................................................................... 144

Free-to-Pitch.Tests............................................................................................................... 145

Future.Perspectives................................................................................................................ 147

References............................................................................................................................... 151

About.the.Author..................................................................................................................... 169

Index..........................................................................................................................................171

vi MODELING FLIGHT
ACKNOWLEDGEMENTS
I sincerely thank the dozens of current and retired employees of the National Aeronautics and Space
Administration (NASA) and its predecessor, the National Advisory Committee for Aeronautics (NACA)
who shared their invaluable corporate memory and personal files in the preparation of this monograph. The
challenge of attempting to chronicle and document over 80 years of research and development activities
was extremely daunting and would have been impossible were it not for the assistance and encouragement
of these individuals. Their direct participation in this project has ensured the preservation and archival
documentation of some of the most remarkable test activities ever conducted at the NASA Langley Research
Center, the NASA Ames Research Center, the NASA Dryden Flight Research Center, and the NASA
Wallops Flight Facility. Special thanks go to the following individuals, who contributed material for this pub-
lication: Long P. Yip, Norman L. Crabill, Mark A. Croom, John Sain, Donald B. Owens, Kevin Cunningham,
Sue B. Grafton, Dan D. Vicroy, and Joseph L. Johnson, Jr.
Special thanks goes to Anthony M. Springer of NASA Headquarters for providing the encouragement and
mechanism for this undertaking and to Lynn Bondurant and Dorothy Watkins of Paragon TEC for coordinat-
ing the preparation and administration of the effort. Sue B. Grafton and Frederick J. Lallman provided
access to many historical documents and photographs at Langley, and Lana L. Albaugh, Edward M.
Schilling, and Jack Boyd contributed at Ames. Thanks also to Garland Gouger and the staff of the Langley
technical library for assistance in accessing documents. Photo archivist Alicia Bagby also provided access
to photographs in the Langley collection. Graphics specialist Gerald Lee Pollard of Langley made available
his outstanding talent and materials.
Thanks also to Mike Fremaux, Ray Whipple (retired), and Don Riley (retired) of Langley; Chuck Cornelison
of Ames; Christian Gelzer of Dryden; Greg Finley of NASA Headquarters for their superb editing efforts and
suggestions; and Janine Wise of NASA Headquarters provided professional layout and organization.
ACKNOWLEDGEMENTS vii
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INTRODUCTION
T
he state of the art in aeronautical engineering has been continually accelerated by the development
of advanced analysis and design tools. Used in the early design stages for aircraft and spacecraft, these
methods have provided a fundamental understanding of physical phenomena and enabled designers to
predict and analyze critical characteristics of new vehicles, including the capability to control or modify
unsatisfactory behavior. For example, the relatively recent emergence and routine use of extremely power-
ful digital computer hardware and software has had a major impact on design capabilities and procedures.
Sophisticated new airflow measurement and visualization systems permit the analyst to conduct micro- and
macro-studies of properties within flow fields on and off the surfaces of models in advanced wind tunnels.
Trade studies of the most efficient geometrical shapes for aircraft can be conducted with blazing speed
within a broad scope of integrated technical disciplines, and the use of sophisticated piloted simulators in
the vehicle development process permits the most important segment of operations—the human pilot—to
make early assessments of the acceptability of the vehicle for its intended mission. Knowledgeable applica-
tions of these tools of the trade dramatically reduce risk and redesign, and increase the marketability and
safety of new aerospace vehicles.
Arguably, one of the more viable and valuable design tools since the advent of flight has been testing of
subscale models. As used herein, the term “model” refers to a physical article used in experimental analy-
ses of a larger full-scale vehicle. The reader is probably aware that many other forms of mathematical and
computer-based models are also used in aerospace design; however, such topics are beyond the intended
scope of this document. Model aircraft have always been a source of fascination, inspiration, and recreation
for humans since the earliest days of flight. Within the scientific community, Leonardo da Vinci, George
Cayley, and the Wright brothers are examples of early aviation pioneers who frequently used models during
their scientific efforts to understand and develop flying machines. Progress in the technology associated
with model testing in worldwide applications has firmly established model aircraft as a key element in new
aerospace research and development programs. Models are now routinely used in many applications and
roles, including aerodynamic data gathering in wind tunnel investigations for the analysis of full-scale
INTRODUCTION 1