Scholars' Mine Masters Theses Student Theses and Dissertations 1974 Experimental determination of improved aerodynamic characteristics utilizing biplane wing configurations Elmer Carl Olson Follow this and additional works at: https://scholarsmine.mst.edu/masters_theses Part of the Aerospace Engineering Commons Department: Recommended Citation Olson, Elmer Carl, "Experimental determination of improved aerodynamic characteristics utilizing biplane wing configurations" (1974). Masters Theses. 3426. https://scholarsmine.mst.edu/masters_theses/3426 This thesis is brought to you by Scholars' Mine, a service of the Missouri S&T Library and Learning Resources. This work is protected by U. S. Copyright Law. Unauthorized use including reproduction for redistribution requires the permission of the copyright holder. For more information, please contact [email protected]. EXPERIMENTAL DETERMI NATI ON OF IMPROVED AEROBYNAMIC CHARACTERI STICS UTI LI ZING BI PLANE ~<VING CONFIGURATIONS BY ELMER CARL OLSON , 1 949- A 'I'HESIS Presented t o the Facult y o f the Graduat e School o f t he UNIVERS I TY 0 F MISSOURI - ROLLA In Part ial Fu lfillment o f the Requi r ements f o r the Degree MASTER OF SCIENCE I N AE ROSPACE ENGINEERING 1974 T 2981 14 0 pages Ap prove d b y c.l 24081.7 ii ABSTRACT Improving the aerodynamic characteristics of an airplane wi th respect to a higher lift coefficient, a lower drag coefficient and a higher lift over drag ratio as a function of angle of attack will make it more efficient, thus conserving energy or improving performance. Investigations were carried out to determine if the aerodynamic characteristics of biplane wing systems could be made more efficient, for low subsonic speeds, than a monoplane of comparable area and aspect ratio . A variable position three-dimensional biplane wing system, and a fuselage that could be fitted with a monoplane wing or the variable position biplane wing system were tested in the University of Missouri-Rolla subsonic wind tunnel at a Reynolds number of 8.7 x 105 per foot. Lift, drag, and pitching moment characteristics of each configuration were investigated to determine the effect of changing the position of the biplane wings relative to each other and how the characteristics compared to those of the monoplane. All the biplane wings tested were shown to have a significant decrease in drag coefficient over the monoplane at a cruise condition. The maximum lift over drag ratios of the biplane wings tested were shown to be significantly higher than that of the monoplane. General trends of drag coefficient and maximum lift over drag ratio and how they vary with the relative position of the biplane wings to one another are presented and compared with the ~haractgr~atics of the monoplane . iii PREFACE The author wishes to express his appreciation to his advisor Bruce P. Selberg, Associate Professor of Aerospace Engineering, and Ronald H. Howell, Professor of Mechanical Engineering for their assistance and guidance in this investigation. Thanks are also due to Mr . Paul Bailey and Mr. Robert Rice for their assistance in taking data, and to the staff of the Department of Mechanical and Aerospace Engineering, particularly to Professor Robert Oetting, for . their assistance in making the UMR subsonic wind tunnel operational. To my father , Elmer E . Olson , and my mother, Mardell A. Olson, I owe the instilling in me of a love for flying and aviation and for making my education possible. And especially to my wife, Beverly, for her help in preparing this manuscript and for her encouragement and understanding during the course of this study . iv TABLE OF CONTENTS Page ABSTRACT. ii PREFACE . iii LIST OF ILLUSTRATIONS . v LIST OF TABLES •... viii I . INTRODUCTION . 1 II. LITERATURE REVIEW . 4 III. DESCRIPTION OF RESEARCH. 6 IV. MODEL DESCRIPTION, INSTRUMENTATION AND TEST PROCEDURE. 7 V. RESULTS AND DISCUSSION . 13 VI. CONCLUSIONS . 28 BIBLIOGRAPHY. 29 VITA. 31 APPENDICES A. ~VIND TUNNEI, DESCRIPTION. 32 B . MODEL DESCRIPTION AND EXPERIMENTAL PROCEDURE 39 C. COMPUTER PROGRAM USED TO REDUCE DATA FOR THE WINGS ONLY PHASE OF TESTING. 60 D. COMPUTER PROGRAM USED TO REDUCE DATA FOR THE FUSELAGE PHASE OF TESTING . •.. 65 E . COMPUTER PROGRAM USED TO COMPUTE THE MOMENT COEFFICIENT FOR THE FUSELAGE PHASE OF TESTING .. 70 F. REDUCED DATA FROM THE WINGS ONLY PHASE OF TESTING. 72 G. REDUCED DATA FROM THE FUSELAGE AND WINGS TOGETHER PHASE OF TESTING . 103 H. MODEL DIMENSIONS . • • . 131 v LIST OF ILLUSTRATIONS Figure Page 1 Fuselage with monoplane . •.. 8 2 Fuselage with biplane wing system . 9 3 Biplane wing system mounted on force balance. 10 4 Summary of aerodynamic characteristics of three-dimensional biplane systems with gap = 1.125, stagger = 1.0 and various decalage angles . 14 5 Maximum efficiency trend of CD at CL = 0.175 with respect to decalage angle for biplane configurations tested. 15 6 Maximum efficiency trend of CD at CL = 0.175 with respect to stagger for biplane configurations tested. 16 7 Maximum efficiency trend of L/D with respect to decalage angle for biplane configurations tested. 18 8 Maximum efficiency trend of L/D with respect to stagger for biplane configurations tested . 19 9 Aerodynamic characteristics of a monoplane and fuselage system . 20 10 Aerodynamic characteristics of a biplane wing and fuselage system with Ga = 1.0, St = 0 . 875, and De 11 Aerodynamic characteristics of a biplane wing and fuselage system with Ga = 1.0, St = 0.875, and De -5° • 22 12 Aerodynamic characteristics of a biplane wing and fuselage system with Ga = 0.875, St = 1.0, and De vi LIST 0~ ILLUSTRATIONS (cont.) Figure Page 13 Moment Coefficient comparison between a monoplane and a biplane with Ga = 1.0, St = 0.875, and De= -5° 26 14 Schematic of UMR subsonic wind tunnel . 34 15 Strain Gage sting balance 35 16 Test section showing parallogram linkage .. 36 17 Balance mount in fuselage . 37 18 Fuselage and biplane wings mounted in test section .. 41 19 Fuselage and monopl ane wing mounted in test section . 42 20 " N" struts disassembled . 43 21 "N" struts mounted on model • 44 22 Balance pod used to mount wings on. 46 23 Steel framework inside fuselage . 47 24 Upper wing mount used on fuselage . 49 25 Velocity distribution in a vertical transverse plane of test section - Part l .. 52 26 Velocity distribution in a vertical transverse plane of test section - Part 2 ... 53 27 Velocity distribution in a vertical longitudinal plane of test section - Part l . 54 28 Velocity distribution in a vertical longitudinal plane of test section - Part 2 . .. 55 29 Aerodynamic characteristics of a biplane wing system with Ga = 1.0, St = 1.125, and De = - 6° .. 73 vii LIST OF ILLUSTRATIONS (cont . ) Figure Page 30 Aerodynamic characteristics of a biplane wing system with Ga = 1 . 0, St = 1.0, and De = - 4° .... 74 31 Aerodynamic characteristics of a biplane wing system with Ga = 1.0, St = 1 . 12S , and De = -4° . 7S 32 Aerodynamic characteristics of a biplane wing system 0 wi th Ga = 1.0 , St = 1 . 12S, and De = - S • 76 33 Aerodynami c characteristics of a biplane wing and fuselage system with Ga = 0.87S , St = 1.12S, and De 34 Aerodynamic characteristics of a bipl ane wing and fuselage system with Ga = 0 . 87S, St = 1 . 125, and De =-6° 1 05 3S Aerodynamic characteristics of a biplane wing and 0 fuselage system with Ga = 0 . 87S, St = 1.0, and De = -S • 106 36 Aerodynamic characteristics of a bipl ane wing and fuselage system with Ga = 0.87S, St = 0.875 , and De LIST "0:F TABLES Table Page I Summary of Aerodynamic Characteristics for Three Biplane Wing Systems and Their Comparison with the Monoplane . 24 II Velocity Distribution in the Vertical Transverse Plane of Test Section 50 III Velocity Distribution in the Vertical Longitudinal Plane of Test Section 51 l I. INTRODUCTION The recent oil embargo against the United States by the Arab nations has given greater emphasis to the fact that the United States and the nations of the world in general are using up their oil reserves at an alarming rate. Conservation steps have been taken to reduce the amount of fuel used by the transportation segment of the economy. Examples are the 55 mile per hour national speed limit and regulations that allow a right turn on a red light after coming to a full stop. One of the fuel conserving transportation methods that is generally overlooked is general aviation light aircraft. From an amount of fuel used per passenger mile standpoint, the present light aircraft are as efficient, or in some cases more efficient, than the commercial airlines. For example, a Cessna Skyhawk (a single engine, fixed gear, four-place airplane) gets 17.0 miles per gallon, which makes 68.0 passenger miles per gallon. A Cessna Turbo-Centurion (a single engine, retractable gear, six-place airplane) gets 13.43 miles per gallon, which gives 80.58 passenger miles per gallon. This compares with a Boeing 707, 300B series, carrying l57 passengers and getting 0.26 miles per gallon, yielding 41.0 passenger miles per gallon. A McDonnell Douglas DC-lO carrying 255 passengers at 0.22 miles per gallon yields 56.10 passenger miles per gallon. From these few examples, it can easily be seen that the light airplane, at its reduced speed, is a more efficient method of transportation from an energy 2 consumption standpoint. Comparisons can also be made between the light aircraft and the automobile . A flight from Rolla, Missouri to Independence, Missouri is 155 miles, and the same trip by car is 220 miles by the best route. Comparing a Cessna Turbo-Centurion to a typical automobile, it can be shown that the airplane will use 11 .