NASA Aeronautics Book Series - Flying Beyond the Stall: The X-31

429 Pages·2015·10.77 MB·English

by  Douglas A. Joyce

.
Douglas A. Joyce
Library of Congress Cataloging-in-Publication Data
Joyce, Douglas A.
Flying beyond the stall : the X-31 and the advent of supermaneuverability /
by Douglas A. Joyce.
pages cm
Includes bibliographical references and index.
1. Stability of airplanes--Research--United States. 2. X-31 (Jet fighter plane)
3. Research aircraft--United States. 4. Stalling (Aerodynamics) I. Title.
TL574.S7J69 2014
629.132’360724--dc23
2014022571
During the production of this book, the Dryden facility was renamed the
Armstrong Flight Research Center. All references to the Dryden facility have
been preserved for historical accuracy.
Copyright © 2014 by the National Aeronautics and Space Administration.
The opinions expressed in this volume are those of the authors and do not
necessarily reflect the official positions of the United States Government or of
the National Aeronautics and Space Administration.
ISBN 978-1-62683-019-6
90000
9 781626 830196
This publication is available as a free download at
http://www.nasa.gov/ebooks.
Author Dedication v
Foreword: The World’s First International X-Airplane vii
Prologue: The Participants xi
Chapter 1: Origins and Design Development .......................................................1
In the Beginning…: The Quest for Supermaneuverability ........................3
Defining a Supermaneuverable Airplane: The Path to EFM ......................5
Design and Development of the X-31 .................................................13
Fabrication to Eve of First Flight ..........................................................20
Chapter 2: Into the Air: Initial Flight Testing ......................................................33
Preflight Preparations Through Initial Flight Exploration ........................34
Assessing the X-31’s Basic Flying Qualities .........................................38
Whither X-31? Program Relocation to Dryden .....................................43
Program Expansion: Probing the Post-Stall Environment ......................48
Chapter 3: Expanding the X-31’s Research Program .......................................63
The Pinball Simulations ......................................................................64
From Pinball to TUFT ..........................................................................77
PST Aloft: Proving the X-31 “1-v-1” ....................................................84
PST in the Dogfight Arena: Concluding Observations ...........................98
Chapter 4: The X-31 Follow-On Program ........................................................105
Of HUDs and Helmets ......................................................................105
X-31 Handling Qualities and Close-In Combat ...................................109
Tracking Tasks in the High-Alpha Arena ...........................................115
Continuously “Predicting” Aerodynamics ...........................................118
The X-31 and JAST’s Quest for “Quasi-Tailless” Flight .......................118
The X-31 “Goes to Sea” ...................................................................123
The X-31 as a Quasi-Tailless Ground Attacker ...................................130
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Flying Beyond the Stall
Chapter 5: Desert Disaster, Triumph in Paris, and a New VECTOR .................139
A Matter of Pitot Icing… ..................................................................140
On to Paris ......................................................................................146
The X-31 Flies at Le Bourget ............................................................158
VECTOR for the Future .....................................................................162
Chapter 6: Program Management and Direction ............................................175
The International Partnership ............................................................175
Contractor, Government, and ITO Responsibilities ..............................178
Costs, Cost Analysis, and Program Funding .......................................184
Chapter 7: The X-31 in Retrospect ..................................................................189
In Sum… ........................................................................................189
Lessons Learned ............................................................................193
Epilogue ...........................................................................................................217
Appendices:
Appendix 1: Disseminating X-31 Research Results and Lessons ........221
Appendix 2: X-31 Flight Log .............................................................239
Appendix 3: X-31 Dimensions, Weights, and Performance
Specifications ..................................................................................293
Appendix 4: X-31 Chronology ...........................................................297
Appendix 5: X-31 Pilots and Their Sorties .........................................305
Appendix 6: Acronyms and Abbreviations ..........................................307
Appendix 7: X-31 Lessons Learned: An Expanded View .....................317
Acknowledgments 363
Selected Bibliography 366
About the Author 375
Index 377
iv
Author Dedication
To Phyllis Joyce
The wind under my wings in life
And the thrust vector for this book.
v
X-31 Initial test pilots at Plant 42: (left to right) Fred Knox, Dietrich Seeck, Ken Dyson, and
Karl Lang. (Rockwell)
vi
FOREWORD
The World’s First
International X-Airplane
On Wednesday, October 11, 1990, a small blue-and-white jet took to the air
from Air Force Plant 42 at Palmdale, CA. For the next 38 minutes, it cruised
at 10,000 feet over California’s Antelope Valley, reaching a top speed of 340
miles per hour (mph) before Rockwell International test pilot Norman K.
“Ken” Dyson returned it gently to Earth.
By the standards of the Antelope Valley—known to locals as “Aerospace
Valley” (AV)—it was a seemingly innocuous flight. Over the four previous
decades, AV had witnessed the birth of supersonic flight. Palmdale, one of its
two major communities, was the roost of the Mach 3+ SR-71 Blackbird and its
subsonic stablemate, the U-2. Edwards, less than 25 miles away, was home to
both the Air Force Flight Test Center and the National Aeronautics and Space
Administration (NASA) Ames-Dryden Flight Research Facility (now the NASA
Armstrong Flight Research Center), where exotic high-performance military
and research aircraft routinely flew over its vast, baked dry lakes—Rosamond
and Rogers. In 1977, the Space Shuttle was first flown freely through its skies,
and in 1981, the Shuttle Columbia returned from orbit to land at Edwards,
heralding the era of the reusable, refurbishable spacecraft.
To those unfamiliar with aircraft, at first glance, the little airplane looked
like any other fighter overflying the Mojave Desert. But appearances were
deceiving, for this was the X-31, then the latest of the U.S. X-planes, the leg-
endary research tools of the supersonic era that had pushed back the frontiers
of flight beginning with the Bell XS-1. Each of the X-planes had their own
uniqueness and X-31 was no different in that regard—in fact, it was unique in
many ways. Perhaps the most distinguishing characteristic of the X-31 program
was that it was the only multinational program of the X series of research vehi-
cles. It was the product of German-American interest. The X-31 was intended
to fulfill four goals: demonstrate controlled flight and high agility beyond the
stall, using thrust vectoring that was integrated with electronic flight controls;
investigate the benefits of enhanced maneuverability for future military aircraft
via close-in air combat maneuvering tests; develop design requirements and
vii
Flying Beyond the Stall
a database for future aircraft applications; and validate low-cost international
prototyping. To fulfill those purposes, Rockwell and German manufacturer
Messerschmitt-Bölkow-Blohm (MBB) designed, developed, and built two of
the shapely X-31 aircraft using a variety of new and off-the-shelf components
blended with creative and insightful engineering and design.
Over the next 14 years, through its final Vectoring ESTOL (extreme short
takeoff and landings) Control Tailless Operation Research (VECTOR) flight
(on April 29, 2004), the X-31 accomplished all this and more. As the program
drew to a close, it received several major awards, notably the American Institute
of Aeronautics and Astronautics (AIAA) Aircraft Design Award (September
1994). In July 1995, with the program then thought to be concluded, the
Smithsonian Institution presented the X-31 International Test Organization
with the prestigious National Air and Space Museum Trophy for Current
Achievement, an honor established to recognize extraordinary service in air
and space science and technology. In making the award, Smithsonian Provost
Robert S. Hoffmann stated the following:
The X-31 International Test Organization is being awarded the
1995 Trophy for Current Achievement for an unprecedented
record of engineering and flight exploration accomplishments
in the past year. You have culminated a highly successful experi-
mental program with a series of momentous “firsts” in aviation
history, demonstrating the significant value of post-stall agility in
close-in air combat, developing and demonstrating revolutionary
helmet-mounted visual and aural pilot aids for situational aware-
ness under WVR [within visual range] combat conditions, and
conducting an epoch-making series of flights in which the X-31
employed its thrust vectoring to demonstrate the feasibility of
tailless flight at supersonic speeds.1
It should also be noted that, consistent with its heritage, it was awarded
the 1995 German Society for Aeronautics and Astronautics (DGLR) Willy
Messerschmitt Award for collaboration in international aeronautical research
and development (R&D).
But the X-31 was far from done, and though “retired,” it returned to the air
nearly 6 years later, in February 2001—itself a remarkable and unprecedented
milestone. When it did so, it was in skies far removed from the harsh, hot bleak-
ness of the Mojave. Flying from verdant Patuxent River Naval Air Station, on
the shores of Maryland’s picturesque Chesapeake Bay, it served as an R&D asset
to test new naval operational concepts enabled by thrust vectoring. There, it
simulated extreme short takeoff and landings for operations on aircraft carriers,
viii
Foreword
approaching to land at hitherto unachievable angles of attack (reduced speed
and energy) with precise control to flare and touchdown. Altogether, the two
X-31 aircraft (the first of which had crashed in January 1995; fortunately, the
pilot ejected successfully, though he did sustain relatively serious injuries on
landing in his parachute) completed over 660 flights, making the program
extraordinarily productive for the amount of money and effort the United
States and Germany had invested in it. More than this, as previously stated,
the X-31 represented a unique international flight-testing and flight-research
partnership; it was the first—and, to this time, only—X-series airplane with
such international involvement. It served, in the words of one summary report,
“as a benchmark for future international cooperation and achievement” in
aeronautics.2 Recognizing its significance, the International Council of the
Aeronautical Sciences (ICAS) awarded the American and German X-31 teams
its Theodore von Kármán Award for international cooperation in aeronautics,
hailing their “over 20 years of successful trans-Atlantic R&D [research and
development] teamwork producing the first-ever international X-plane and
significant breakthroughs in thrust-vectoring control.”3
This book is the story of the X-31 program, ranging from the visionary
Wolfgang Herbst, a remarkable pioneer of extreme maneuverability who tragi-
cally died before his concept realized its fullest potential, to the realities and
discoveries of flight research in the skies over NASA Dryden and Patuxent
River. It is to the men and women of the X-31 International Test Organization,
and all those on both sides of the Atlantic—in the multitude of contractors,
research centers, and governmental departments—who conceived, designed,
supported, funded, maintained, flew, and employed the X-31 for its various
research purposes, that the author dedicates this book with the greatest respect
and admiration.
ix