equations that are unit‐agnostic will allow the reader to use either English or SI consistent units as desired. Thus, the assumption throughout this text (unless otherwise specified) is that equations are based on standard, consistent units.
To the reader – thank you for picking up this book. We are passionate about flight testing and are eager to share our deep interest in this domain with you. We hope that this book will be rewarding, enriching, and fascinating.
James W. GregoryColumbus, OhioTianshu LiuKalamazoo, Michigan
September 6, 2020
Acknowledgements
The authors are grateful for a wide array of colleagues, collaborators, and students who have shaped our thinking and provided input and feedback on this book.
JG would like to thank Profs. Stacy Weislogel and Gerald M. Gregorek, who as pioneers of educational flight testing in the 1970s were inspirations for this work. Prof. Hubert C. “Skip” Smith was also generous with ideas and resources along the way. The flight education department and colleagues in Aviation at The Ohio State University have been extremely helpful in providing tactical support over the years – D. Gelter, D. Hammon, B. Mann, S. Morgan, S. Pruchnicki, C. Roby, B. Strzempkowski, and S. Young. Special thanks go to Profs. Jeffrey Bons and Cliff Whitfield, who helped review significant portions of a near‐final version of the manuscript. (Any remaining errors or inaccuracies are solely the responsibility of the authors). Portions of this book were written in 2014–15 while JG was on sabbatical at the Technion in Israel; the support of Ohio State University and the Fulbright foundation is gratefully acknowledged.
JG also wishes to extend special thanks to Dr. Matt McCrink, who assisted with many of the flight tests presented in this book and coauthored the final chapter on UAV flight testing. He has been an instrumental sounding board and key partner throughout this project.
TL would like to thank M. Schulte, M. Mandziuk, S. Yurk, M. Grashik, S. Woodiga, P. Wewengkang, D. M. Salazar, and WMU's College of Aviation.
Numerous colleagues, including M. Abdulrahim, J. Baughn, K. Colvin, C. Cotting, K. Garman, B. Gray, C. Hall, J. Jacob, J. Kidd, K. Kolsti, J. Langelaan, B. Martos, N. Sarigul‐Klijn, R. Smith, J.P. Stewart, A. Suplisson, A. Tucker, J. Valasek, C. Walker, O. Yakimenko, and M. Yukish, helped influence the presentation of ideas in this book. The Flight Test Education Workshop, hosted by the USAF Test Pilot School, was a particularly helpful resource for materials and connections. A. Bertagnolli of Continental Aerospace Technologies (Continental Motors) and J. J. Frigge of Hartzell Propeller generously provided data and resources for the text. C. Daniloff, K. King, R. Heidersbach, H. Henley, K. King, N. Lachendro, H. Rice, H. Sakaue, B. Stirm, and R. Winiecki gracefully allowed their images or likenesses to be published in this book.
JG and TL also wish to thank their doctoral advisor, Prof. J. P. Sullivan of Purdue University, for his encouragement for us to pursue and finish this project.
Finally, JG and TL especially thank their families for their patience and support over the many years it took to complete this project.
About the Companion Website
The companion website for this book is at
https://www.wiley.com/go/flighttesting
Scan this QR code to visit the companion website.
1
Introduction
Flight testing is seemingly the stuff of legends, with tales of derring‐do and bravery, spearheaded by great pilots such as Yeager, Armstrong, Glenn, and others. But what exactly is flight testing all about? What is being tested, and why? What's the difference between a test pilot and a flight test engineer? Is flight testing an inherently dangerous or risky activity?
With this book, we hope to show that flight testing is both exciting and accessible – we hope to make flight testing understandable and achievable by the typical undergraduate aerospace engineering student. The basic principles of flight testing can be explored in any aircraft, all the while remaining safely well within the standard operating envelope of an aircraft. This book will introduce students to the principles that experienced flight test engineers work with as they evaluate new aircraft systems.
Flight testing is all about determining or verifying the performance and handling qualities of an aircraft. These flight characteristics may be predicted in the design and development stages of a new aircraft program, but we never really know the exact capabilities until the full system is flown and tested. Most aircraft flight testing programs are focused on airworthiness certification, which is the rigorous demonstration of all facets of the flight vehicle's performance and handling characteristics in order to ensure safety of flight.
We also wish to highlight that most flight testing should not incur the levels of risk and danger that we associate with the great test pilots of the 20th century. Their bravery was indeed laudable, since they ventured into flight that no human had done before, such as breaking the “sound barrier” or being the first person to walk on the Moon. But, if done correctly, flight testing should be a methodical process where risks are managed at an acceptable level, where human life and property are not exposed to undue risk. Even more hazardous flight testing such as flutter boundary determination or spin recovery should be done in a methodical, well‐controlled manner that mitigates risk. In fact, most flight testing, at least to an experienced professional, can be almost mundane (Corda 2017).
Nor is flight testing an individualistic activity where an intrepid pilot relies solely on their superlative piloting skills to push the aircraft to its limits, as suggested by the caricature in Figure 1.1. Quite the contrary, flight testing is a team effort with many individuals carefully contributing to the overall success of a flight testing program (see Figure 1.2). There is, of course, a pilot involved whose job it is to fly the aircraft as precisely and accurately as possible to put the aircraft through the necessary maneuvers to extract the needed performance or handling data. If an aircraft can carry more than just the pilot, then there is almost always a flight test engineer on board. The flight test engineer is responsible for preparing the plan for the flight test and for acquiring the data in flight while the pilot puts the aircraft through the required maneuvers. Beyond the role of the flight test engineer, there are many others involved – including those who monitor systems and downlinked data on the ground, data analysts who post‐process and interpret the data after the test is complete, and program managers who set the strategic direction for the program and make budgetary decisions.
Figure 1.1 The caricature view of flight test is of an individualistic, cowboy‐like, rugged test pilot who single‐handedly defies danger. Here, Joe Walker playfully boards the Bell X‐1A in a moment of levity.
