Journey in Aeronautical Research A Career at NASA Langley Research Center by W. Hewitt Phillips NASA History Office Office of Policy and Plans NASA Headquarters Washington DC 20546 Monographs in Aerospace History Number 12 November 1998 The use of trademarks or names of manufacturers in this monograph is for accurate reporting and .does not constitute an official endorsement, either expressed or implied, of such pro- ducts or manufacturers by the National Aeronautics and Space Administration. William Hewitt Phillips, January 1945, age 26, then head of the Stability and Control Branch, Flight Research Division. Table of Contents List of Figures ix CHAPTER1 Introduction I CHAPTER2 Early Life Through the College Years 3 Parents and Early Years 3 College Years 11 CHAPTER 3 Setting for the Research Work at Langley 17 History 17 Description of Surroundings 17 First Assignments in Flight Research 19 CHAPTER 4 Flying Qualities 21 Flying Qualities Tests 22 Stall Tests 26 Brewster XSBA- l Airplane 27 Short-Period Longitudinal Oscillations 28 Spiral Instability 29 Snaking Oscillations 30 Rudder Deflection Required for Trim 31 Progress in Flying Qualities Research 32 Static Longitudinal and Directional Stability 33 CHAPTER 5 Analytical Studies 37 Graphical Solution of the Quartic Equation 40 Solution of a Nonlinear Problem 41 Computation of Lateral Oscillation Characteristics 44 Monographs in Aerospace History Number 12--Journey in Aeronautical Research v CHAPTER6 Problems Encountered as a Result of Wartime Developments 47 The Quest for Reduced Control Forces 48 Flettner Tabs, Servo Tabs, Spring Tabs, and Whirlerons 50 Research on Closely Balanced Controls 53 A Control Surface Hinge-Moment Balancing Mechanism 56 A Spoiler Operated Servo Control 57 The Introduction of Swept Wings 58 CHAPTER7 Effects of World War H on Research Activities 61 Effect of the War on Living and Working Conditions 61 Some Effects of the War on Research Activities 62 CHAPTER 8 New Ideas--The Fruits of Research 67 The First Piloted Simulator Used for Research at Langley 67 Roll Coupling 69 A Method for Determining the Moments and Products of Inertia of Full-Scale Airplanes 74 Towed Bodies 75 CHAPTER9 Unsteady Lift 77 Spring-Tab Flutter 78 Effect of Unsteady Lift on Snaking Oscillat_ ons 81 CHAPTER 10 An Automatic Aileron Trim Device fc=r Personal Airplanes 85 Development and Tests of the Trim Device 85 CHAPTER 11 New Areas of Research 91 The Wing-Flow Technique 91 Power Controls and Pilot-Induced Oscillations 97 Human Response Characteristics 101 Landing Studies 102 CHAPTER 12 Measurement of Turbulence in the Atmosphere 105 Analytical Studies of the Accuracy of Turbu ence Data from Flight Records 106 Measurements of the Spectrum of Atmospheric Turbulence Over a Large Range of Wavelengths 109 vi Monographs in Aerospace Hi ¢tory Number 12--Journey in Aeronautical Research CHAPTER 13 Gust Alleviation 113 Background and Analysis of Gust Alleviation 115 Design and Test of a Gust-Alleviated Airplane 121 Analytical Studies of Additional Problems 128 Future Possibilities of Gust Alleviation 129 Review of Work by Ren6 Hirsch 130 Later Studies by Other Investigators 132 CHAPTER 14 Lateral Response to Random Turbulence 133 Modeling the Turbulence 133 Calculation of Response 134 CHAPTER 15 Accident Investigations 137 BAC-I 11 Crash Near Omaha, Nebraska, on August 6, 1966 137 Crash of Convair B-58 Bomber 140 Accidents of the Republic F-105 Thunderchief Airplane 144 Analytical Study of the F-84 Following Accident in High-Speed Flyby 145 Accidents of the Beech Bonanza Involving In-Flight Structural Failures 146 CHAPTER 16 NACA Flight Research on the Vought F8U-1 Airplane 151 Results of the Last NACA Flying Qualities Investigation 152 CHAPTER 17 A Couple of Bloopers! 155 Improving on the Wright Brothers 155 Relearning the Laws of Angular Momentum 158 CHAPTER18 Administration of the Langley Research Center 159 Organization of the Center 159 NACA Reports 160 Approval and Support of Research 162 The Committee Organization of the NACA 163 Formal NACA Conferences 164 Preparation of NACA and NASA Talks 165 Meetings of Professional Societies 165 Meetings with Visitors 166 Monographs in Aerospace History Number 12--Journey in Aeronautical Research vii CHAPTER 19 Dawn of the Space Age 167 References 169 APPENDIX I Early Autobiography 175 APPENDIX II Bibliography of Reports by William Hewitt Phillips 181 NACA or NASA Reports 181 Papers Other Than NACA or NASA Report_ 184 Unpublished Papers in NASA Langley Research Center Library 186 APPENDIX III Solution of a High School Geometry Problem 187 APPENDIX IV Solution of Quartic Equation in Terms of Two Parameters by Use of Charts 191 Index 195 About the Author 201 viii Monographs in Aerospace Hi,:tory Number 12--Journey in Aeronautical Research List of Figures Figure 2.1 Scenes from childhood. 4 Figure 2.2 My father's steam-powered torpedo boat destroyer after restoration. 5 Figure 2.3 Our summer cottage at Long Beach, Gloucester, Massachusetts. 6 Figure 2.4 Scenes in Belmont, Massachusetts. 7 Figure 2.5 My nonflying scale model airplanes. 8 Figure 2.6 Vultee YA-19 attack bomber with Pratt and Whitney R-2800 engine installed. 13 Figure 2.7 Mechanics in the Installation Department of Pratt and Whitney in front of YA-19 airplane. 14 Figure 2.8 Model glider equipped with phugoid damper. 15 Figure 3.1 Airplanes being tested at the NACA Flight Research Hangar in 1944. 20 Figure 4.1 Pictures of me with two of the airplanes tested in my first years at the NACA. 23 Figure 4.2 Vought-Sikorsky XF4U-1 airplane. 24 Monographs in Aerospace History Number 12--Journey in Aeronautical Research ix Figure 4.3 Curtiss P-40 airplane. 24 Figure 4.4 Hawker Hurricane airplane. 25 Figure 4.5 Supermarine SpiOqre airplane. 25 Figure 4.6 North American BT-9B airplane. 27 Figure 4.7 Lockheed 14H transport airplane, a later model of one of the original 16 airplanes on which Gilruth's flying qualities requirements were based. 29 Figure 4.8 Grumman XTBF-3 airplane, a torpedo bomber used in the war in the Pacific. 33 Figure 4.9 Portion of tail area that must be considered ineffective to obtain agreement between calculated and measured variation of rudder angle with sideslip angle (low-wing airplanes). 34 Figure 5.1 Time histories of aileron snaking oscillations as calculated by my theory. 43 Figure 6.1 Types of control surface aerodynamic balance. 49 Figure 6.2 Diagramatic sketches of aerodynamically operated servo controls. 51 Figure 6.3 All-movable horizontal tail installed on Curtiss XP-42 airplane. 54 Figure 6.4 Comparison of stick forces in rapid l,ull ups with Curtiss P-40 airplane and Curtiss XJ_-42 airplane. 55 Figure 6.5 Diagram of operation of vane-type s,,rvo control. 58 Figure 6.6 Photograph of test model of vane-type servo control. 59 Figure 6.7 Bell L-39 airplane incorporating experimental swept wing to study low-speed effects of wing sweep. 60 x Monographs in Aerospace Hi¢tory Number 12--Journey in Aeronautical Research Figure 7.1 Republic P-47D-30. 64 Figure 7.2 Mitsubishi O0 airplane, popularly known as the Japanese Zero. 64 Figure 8.1 Yaw chair used for studying ability of human pilots to control lateral oscillations. 68 Figure 8.2 Drop model of the XS-1 airplane. 7! Figure 8.3 Flight data from drop test of XS-1 model. 71 Figure 8.4 Devices made to illustrate the effect on stability during rolling motion of the equality or inequality of stiffness about the pitch and yaw axes. 73 Figure 8.5 Test airplane as set up for determining moment of inertia and tilt of the principal longitudinal axis of inertia. 75 Figure 9.1 Diagram showing optimal location of mass-balance weight to prevent flutter of spring tab. 79 Figure 9.2 Schematic diagram of installation of tab balance weight ahead of flap hinge line. 79 Figure 9.3 Drawing of balance weight installation in B-34 vertical tail. 80 Figure 9.4 Photograph of balance weight installation in B-34 vertical tail. 81 Figure 9.5 Amplitude and phase angle of the circulatory lift of elliptical wings. 83 Figure 9.6 Damping of oscillations of a weathervane computed by finite-span, quasi-static, and two-dimensional theories. 84 Figure 10.1 Schematic diagram of automatic aileron trim control device. 87 Monographs in Aerospace History Number 12--Journey in Aeronautical Research rd Figure 11.1 Wing-flow model and test apparatus mounted on P-51 wing. 92 Figure 11.2 Drawing of semispan model of rectangular wing with full-span flap used in wing-flow test_. 93 Figure 11.3 Typical data from wing-flow test. 94 Figure 11.4 Wing-flow model of Vought F7U-1 Cutlass. 96 Figure 11.5 Full-scale Vought F7U-1 Cutlass. 97 Figure 11.6 Simple simulator used to demonstrate to pilots the possibility of pilot-induced oscillations caused by characteristics of the power control system. 99 Figure 11.7 Normal acceleration during formation flights of F4U- 4B airplane and F9F-3 airplane with alternate positions as lead airplane and following airplane; F4U-4B with and without power controls. 100 Figure 12.1 Error in harmonic amplitude due to finite length of record for various phase angles of harmonic. 107 Figure 12.2 Plot of amplitude versus phase angle for waves with various ratios of wavelength to record length. 108 Figure 12.3 Photograph of F9F-3 airplane show, ng special instrumentation for turbulence meas.trements. 109 Figure 12.4 Power spectrum of gust vertical velocity for wavelengths of lO feet to 60,O00 feet 110 Figure 13.1 Waterman's airplane incorporating _eings attached to fuselage with skewed hinges.