DESIGN OF A HYBRID ROCKET / INFLATABLE WING UAV By CORY SUDDUTH Bachelor of Science in Mechanical and Aerospace Engineering Oklahoma State University Stillwater, OK 2012 Submitted to the Faculty of the Graduate College of the Oklahoma State University in partial fulfillment of the requirements for the Degree of MASTER OF SCIENCE December, 2012 DESIGN OF A HYBRID ROCKET / INFLATABLE WING UAV Thesis Approved: Dr. Jamey Jacob Thesis Adviser Dr. Andy Arena Dr. Joe Conner ii Name: CORY SUDDUTH Date of Degree: DECEMBER, 2012 Title of Study: DESIGN OF A HYBRID ROCKET / INFLATABLE WING UAV Major Field: MECHANICAL AND AEROSPACE ENGINEERING This paper discusses the design challenges and development of a UAV that transitions from a rocket, which allows the aircraft to reach a target altitude rapidly, and then deploys an inflatable wing from an enclosed shell in midflight to allow for loitering and surveillance. The wing deployment and transition is tested in static and dynamic environments, while the performance and stability of both the aircraft mode and rocket mode are examined analytically. An in-depth discussion of key components, including the design, analysis and testing, is also included. Designing an UAV that transitions from a high velocity rocket, to a slow velocity UAV provides many difficult and unique design challenges. For example, the incorporation of deployable wing technology into a full UAV system results in many design constraints. In this particular design inflatable wings are used to generate lift during aircraft mode, and the stabilizing fins for the main wing also acted as the fins for the vehicle during its rocket phase. This required the balancing of the two different vehicle configurations to ensure that the aircraft would be able to fly stably in both modes, and transition between them without catastrophic failure. Significant research, and testing went into the finding the best method of storing the inflatable wing, as well as finding the required inflation rate to minimize unsteady aerodynamic affects. Design work was also invested in the development of an inflation system, as it had to be highly reliable, and yet very light weight for use in this small UAV. This paper discusses how these design challenges were overcome, the development and testing of individual sub-components and how they are incorporated into the overall vehicle. The analysis that went into this UAV, as well as methods used to optimize the design in order to minimize weight and maximize the aircraft performance and loitering time is also discussed. iii TABLE OF CONTENTS CHAPTER PAGE I. INTRODUCTION .................................................................................................................. 1 1.1 MOTIVATION AND SCOPE ...................................................................................... 1 1.2 GOALS AND OBJECTIVES ....................................................................................... 2 II. REVIEW OF LITERATURE ................................................................................................ 6 2.1 DEPLOYABLE RIGID WING AIRCRAFT ................................................................ 6 2.2 INFLATABLE-WINGED AIRCRAFT ...................................................................... 10 2.2.1 NASA I2000 ...................................................................................................... 11 2.2.2 ILC DOVER FASM/QUICKLOOK .................................................................. 16 2.3 PREVIOUS OSU RESEARCH ................................................................................... 18 2.4 PYRO-VALVES ......................................................................................................... 20 III. INFLATABLE WING STUDIES ...................................................................................... 26 3.1 BACKGROUND INFORMATION ............................................................................ 26 3.2 THERORETICAL AERODYNAMIC PERFORMANCE ......................................... 28 3.3 WING LOADING AND LEAK RATE TESTS ......................................................... 34 3.4 INITIAL DEPLOYMENT TESTS.............................................................................. 38 IV. INFLATION SYSTEM DEVELOPMENT ....................................................................... 47 4.1 INFLATION METHODS ........................................................................................... 47 4.2 PROOF OF CONCEPT ............................................................................................... 50 4.3 WING VOLUME TESTING ...................................................................................... 54 4.4 DESIGN OPTIMIZATION AND CONSTRUCTION ............................................... 59 4.5 INFLATION SYSTEM TESTING ............................................................................. 66 iv CHAPTER PAGE V. AIRCRAFT DESIGN AND CONSTRUCTION ................................................................ 70 5.1 CONCEPTUAL DESIGN ........................................................................................... 70 5.2 AIRCRAFT CONFIGURATIONS AND SELECTION ............................................. 73 5.3 DESIGN OPTIMIZATION AND IN-DEPTH ANALYSIS ....................................... 77 5.4 CONSTRUCTION ...................................................................................................... 90 VI. AIRCRAFT EXPERIMENTS ......................................................................................... 105 6.1 WING DEPLOYMENT TEST.................................................................................. 105 6.2 AIRCRAFT FLIGHT TEST – FIRST LAUNCH ..................................................... 106 6.3 AIRCRAFT FLIGHT TEST – FULL SYSTEM ...................................................... 113 VII. CONCLUSIONS AND FUTURE WORK ..................................................................... 121 7.1 CONCLUSIONS ....................................................................................................... 121 7.2 FUTURE WORK ...................................................................................................... 122 v CHAPTER PAGE VIII. APPENDICES .............................................................................................................. 128 A. UNDERGRADUATE SPACECRAFT DESIGN PROJECTS .................................. 128 B. WING LOADING TEST DATA ................................................................................ 131 C. CO2 CARTRIDGE SIZING TABLE ......................................................................... 132 D. WING VOLUME TESTING DATA ......................................................................... 133 E. PYRO-VALVE INFLATION SYSTEM PREPARATION ........................................ 135 F. AN THREAD SIZE COMPARISON ......................................................................... 140 G. EARLY AIRCRAFT STABILITY CALCULATIONS ............................................. 141 H. AIRCRAFT OPTIMIZATION PROGRAM .............................................................. 143 H.1 USER INTERFACE .......................................................................................... 143 H.2 PUSHER CONFIGURATION RESULTS ........................................................ 146 H.3 TRACTOR CONFIGURATION RESULTS ..................................................... 147 H.4 EDF CONFIGURATION RESULTS ................................................................ 148 H.5 PROGRAM CODE - CLEAR ............................................................................ 149 H.6 PROGRAM CODE – PUSHER CONFIG ......................................................... 150 H.7 PROGRAM CODE – TRACTOR CONFIG...................................................... 157 H.8 PROGRAM CODE – EDF CONFIG ................................................................. 164 I. COMPONENT DRAG ANALYSIS ............................................................................ 171 I.1 USER INTERFACE ............................................................................................ 171 I.2 PROGRAM CODE – DRAG ANALYSIS ......................................................... 172 J. AIRCRAFT ANALYSIS ............................................................................................. 175 J.1 WING AIRFOIL DATA CORRECTED FOR 3D EFFECTS ............................ 175 J.2 TAIL AIRFOIL DATA ....................................................................................... 176 J.3 PROPULSION ANALYSIS DATA ................................................................... 177 J.4 AIRCRAFT STABILITY AND CONTROL SURFACES ................................. 179 J.5 CONTROL SURFACE SERVO SIZING ........................................................... 181 K. AIRCRAFT FLIGHT TEST – FIRST LAUNCH RESULTS .................................... 182 L. AIRCRAFT FLIGHT TEST – FULL SYSTEM RESULTS ...................................... 184 IX. REFERENCES ................................................................................................................ 185 vi LIST OF TABLES TABLE PAGE 3.1.1 ILC DOVER INFLATABLE WING SPECIFICATINS ............................................. 27 3.2.1 CFD RESULTS INCLUDING NACA 4318 AIRFOIL .............................................. 31 3.2.2 AIRFOIL DATA COMPARISON, RE=500,000 ........................................................ 32 3.4.1 DYNAMIC INFLATION TEST RESULTS ..............................................................