A GENERIC STABILITY AND CONTROL TOOL FOR FLIGHT VEHICLE CONCEPTUAL DESIGN: AEROMECH SOFTWARE DEVELOMENT by GARY JOHN COLEMAN JR. Presented to the Faculty of the Graduate School of The University of Texas at Arlington in Partial Fulfillment of the Requirements for the Degree of MASTER OF SCIENCE IN AEROSPACE ENGINEERING THE UNIVERSITY OF TEXAS AT ARLINGTON May 2007 Copyright © by Gary John Coleman Jr. 2007 All Rights Reserved ACKNOWLEDGEMENTS This work could not have been possible without the support of several individuals whom I wish to acknowledge. I would like to express my appreciation to my advisor, Dr. Bernd Chudoba, for his support, encouragement, feed-back and even his constructive criticism. The high level of academic, professional and engineering standards he sets drive and challenges his students to grow and learn throughout their education. This Thesis is the implementation and application of methodology and mathematical frame work derived by Dr. Chudoba. With out this foundation the current research could not have been conducted. I would like to acknowledge the contribution of Kiran Pippalapalli of the AVD Lab to the present research. His initial work on the AeroMech software has been invaluable, and has provided an excellent starting point for my research. I would also like to thank him for his guidance, advice and friendship during my graduate studies. Dr. Edward Lan of the University of Kansas has been instrumental during this research in aiding with the use and application of his aerodynamic prediction tool VORSTAB. His insight into both the computation and physical aspects of aerodynamics have been of great value during this research Gerald C. Blausey (former Lockheed Martin flight dynamists) and Robert G. Hoey (former USAF flight test engineer) have contributed greatly to my understanding iii of stability and control and its application to both design and flight testing. Their experience, insight, and timely response to my questions are greatly appreciated, and have directly influenced this research. I would like acknowledge the contributions of Dr. Danielle Soban (Georgia Institute of Technology) and John Jeffery (J2 Aircraft Solutions Ltd.). Their timely feed-back and experience with the application of stability and control in design have been very helpful for this research. I would like express my appreciation to the AVD lab team members, Xiao Huang, Andy Huizenga, Amit Oza, Bryan Mixon, Kristen Roberts, Brad Mixon, and Nauman Mhaskar. Their friendship and assistance have made my graduate studies at the University of Oklahoma and the University of Texas at Arlington an enjoyable experience. I would like to thank my parents, for their support, direction and encouragement. I would also like to thank my younger brothers, Daniel, Dennis and Nick for their “constructive” criticism and feed-back during my Masters research. I hope I can return the favor someday. Finally, I would like to thank my fiancé Jessica, without her love, understanding and support this work could not have been possible. Her friendship and laughter constantly remind me of what is truly important. April 19, 2007 iv ABSTRACT A GENERIC STABILITY AND CONTROL TOOL FOR FLIGHT VEHICLE CONCEPTUAL DESIGN: AEROMECH SOFTWARE DEVELOMENT Publication No. ______ Gary John Coleman Jr., M.S. The University of Texas at Arlington, 2006 Supervising Professor: Dr. Bernd Chudoba During the conceptual design (CD) phase, various solution concepts must, and should, be explored to select the best flight vehicle size and configuration in order to meet the mission requirements. As the aerospace industry advances novel aerospace flight vehicle configurations promising larger operational performance and overall efficiency, demanding integrated flight vehicles like the flying wing configuration (FWC) or blending wing body (BWB) are under investigation. Some of these novel configurations rely on novel control effectors (CE) and complex flight control systems in order to obtain the desired performance objectives. Clearly, stability and control plays an important roll in the design of advanced flight vehicles. v Chudoba1 recognized that that the conceptual design of such vehicles requires a truly generic stability and control approach to enable consistent comparisons of novel aircraft configurations with conventional aircraft aircraft shapes. Consequently, AeroMech analyzes both symmetric and asymmetric flight vehicles in symmetric and asymmetric flight conditions. The methodology and software AeroMech contributes to (1) sizing primary control effectors to possess adequate physical control power throughout the flight envelope, the tool (2) provides trimmed aerodynamics for improved performance-optimal stability and control solutions, and (3) it analyses static and dynamic stability in all axes (open and closed loop) for ensure flight vehicle safety and compliance with certification regulations throughout the flight envelope. The development of this methodology and software has been following three fundamental steps: (1) derivation of the AeroMech methodology and mathematic frame- work, (2) development of the stand-alone AeroMech prototype software for validation purposes, and (3) integration of AeroMech into the multi-disciplinary design tool AVDS-PrADO for multi-disciplinary flight vehicle synthesis. With the first step accomplished by Chudoba1, the second step initiated by Pippalapalli6, the present work describes the completed development of the stand-alone AeroMech prototype software and its validation using the Northrop YB-49 flying wing as the primary case study demonstrating physical correctness of the algorithm but in particular the software’s potential to enable true control-configured vehicle (CCV) design during the early conceptual design phase. vi TABLE OF CONTENTS ACKNOWLEDGEMENTS.............................................................................................iii ABSTRACT ..................................................................................................................... v TABLE OF CONTENTS ...............................................................................................vii LIST OF ILLUSTRATIONS........................................................................................... xi LIST OF TABLES.......................................................................................................... xv NOTATION.................................................................................................................xviii Chapter 1. INTRODUCTION AND OBJECTIVES.............................................................. 1 1.1 Introduction..................................................................................................... 1 1.2 Background, Research Approach and Objectives .......................................... 8 1.2.1 Research Objectives....................................................................... 10 2. STABILITY AND CONTROL IN CONCEPTUAL DESIGN.......................... 12 2.1 Review of Stability and Control Techniques in Conceptual Design ............ 12 2.1.1 Assessment of the Classical Approach.......................................... 15 2.1.2 Assessment of the State-of-the-Art................................................ 22 2.2 Summary of Results and Prototype System Requirements .......................... 26 3. AEROMECH METHODOLOGY AND THEORY........................................... 28 3.1 Methodology Overview................................................................................ 28 3.2 Input and Control Allocation........................................................................ 32 vii 3.3 Aerodynamic Prediction ............................................................................... 35 3.4 Stability and Control Analysis...................................................................... 40 3.4.1 Steady State 6-DOF Trim Equations of Motion............................ 41 3.4.1.1 Steady-State Straight-Line Flight (SSLF) ........................... 45 3.4.1.2 Steady-State Pull-Up/Push-Over (SSPUPO)....................... 48 3.4.1.3 Steady-State Roll Performance (SSRP)............................... 49 3.4.1.4 Steady-State Turning Flight (SSTF).................................... 52 3.4.1.5 Quasi-Steady-State Take-Off Rotation (QSTORM) ........... 54 3.4.2 Trimmed Aerodynamics ................................................................ 57 3.4.3 Dynamic Stability and Control Analysis ....................................... 60 3.4.3.1 Small Perturbation Equations of Motion............................. 60 3.4.3.2 Dynamic Open and Closed Loop Analysis ......................... 65 3.5 Output Definition.......................................................................................... 70 4. AEROMECH PROTOTYPE SYSTEM DEVELOPMENT .............................. 71 4.1 AeroMech Development Background and Process ...................................... 71 4.1.1 AeroMech Background.................................................................. 71 4.1.2 AeroMech Prototype Software Development Process .................. 74 4.2 Evolution of the AeroMech Prototype Stand-alone Software ...................... 79 4.3 Future Work and Recommendations .......................................................... 104 5. APPLICATION OF AEROMECH IN CONCEPTUAL DESIGN .................. 106 5.1 Stability and Control ‘Road Map’ to Conceptual Design........................... 106 5.2 Validation Case Study: Northrop YB-49 Flying Wing .............................