Wind Tunnel Evaluation of 6 feet Spanned Mini Aerial Vehicle (Kadet)

Transcription

1 Wind Tunnel Evaluation of 6 feet Spanned Mini Aerial Vehicle (Kadet) Kailash Kotwani, Hemendra Arya, K Sudhakar Center for Aerospace System and Design Engineering Department of Aerospace Engineering Indian Institute of Technology, Bombay January 2005

2 Introduction This report presents the results of wind tunnel tests conducted on 6 feet spanned MAV (kadet) being developed at CASDE, IIT Bombay. The objective of the tests was to generate basic aerodynamic data related to steady flight conditions and response to control surface settings. Wind tunnel tests were conducted in the 4.25 x 2.75 m Open Circuit Wind Tunnel of the Dept. of Aerospace Engineering, Indian Institute of Science, Bangalore. The details of the model, experimental setup etc are also presented in the report. Kadet Description The full scale model made out of balsa wood was used for testing in wind tunnel. It had hinge mounted aileron, elevator and rudder control surfaces. It had maximum weight of 4 kgs. Its configuration had high wing, single engine tractor and monoplane trainer vehicle with tricycle landing gear with stearable nose wheel. All three axes controls and throttle were operated by a four channels radio controlled command unit. The power plant included a OS Max 2 stroke cylinder, 7.5 cc glow plug engine which develops 1.59 bhp at rpm. The engine drives a tractor Master Airscrew propeller of 11x8 size, a 2 bladed fixed pitch which develops a maximum thrust of 1.6 kg at sea level. The airframe was constructed using balsa wood sheet for fuselage, horizontal tail, vertical tail and ailerons. The wing is formed by balsa wood, plywood, veneer and Monokote covered construction. The fuselage is essentially rectangular in cross section. Engine mounting is wooden frame. Typical geometric details are given in shown in Fig. 2, 3, 4 and 5. The wind tunnel model of Kadet was prepared by modifying the above mentioned airplane for accommodating strain gauge balance inside the fuselage. A rectangular box made out of 1/8 of mild steel was inserted in the fuselage to support the balance fixtures and to provide strength. The entire model was fixed on the model end of the balance while the sting end of the balance to an extension attachment which inturn to the wind tunnel sting. A view of the model mounted to the sting inside the test section of the wind tunnel is shown in Fig. 1. Experimental Setup Forces and moments acting on the model in the wind tunnel were measured by a six component strain gauge balance named as WT7. The ratings of the balance and axes system employed are given in Table 1 and Fig. 6. The balance was calibrated and the accuracy of the measurement system was found to be better than about 0.5% of the rated load. The output data from the balance was fed to the precision amplifiers (Ectron, USA) and the output of the amplifiers to computer based data acquisition and processing 2

3 system. The system consisted of analog to digital conversion facility, PC 486, printer etc. Outputs corresponding to wind speed, pitch and yaw settings of the sting were also connected to input channels of the data acquisition system. The software used was capable of enabling of acquisition of balance data, sting pitch and yaw, tunnel wind speed and then computing results. The results were obtained as nondimensional coefficients and plots both in wind axes and body axes. Wind tunnel tests were conducted at a steady wind speed of about 20 m/sec as this was the normal flight speed for the vehicle. After setting the model test configuration and allowing one hour for warming up of instrument wind-off data were acquired at different pitch angle settings 6 0 to at 2 0 intervals and yaw settings of 6 0 to +6 0 at 2 0 intervals. The wind tunnel was started and the wind speed adjusted to about 20m/sec. At this steady wind speed the data was again acquired for the same pitch and yaw angle settings as at wind-off. Using wind-on and wind-off data, the non-dimensional coefficients were computed. Results: The results obtained from the experiments conducted in all the configurations tested (Table 2) are presented in the form of tables (Table 3 to Table 32 ) and figures (Fig. 7 to 36 ). All forces and moments were measured with reference to the balance cnetre and then transferred to the quarter chord line which was 8.5 cm ahead of balance center. Note : Control surface deflections are considered positive if they produce a negative moment about their respective axis. 3

4 Details of Kadet Fuselage Overall length = cm Maximum width = 12 cm Wing Airfoil section = Given in Fig. 3 Span = cm Chord Length = 29.5 cm Dihedral Angle = 3 deg Area = m 2 Quarter chord line 8.5 cm ahead of balance center C L = Lift Coefficient C D = Drag Coefficient C Y = Side Force Coefficient C M = Pitching Moment Coefficient Cl-R = Rolling Moment Coefficient C N = Yawing Moment Coefficient Abbreviations 4

5 Fig. 1: Kadet Model in Wind Tunnel 5

6 Drawings (All Dimensions are in cm) Fig 2: Horizontal and Vertical Tail 6

7 Fig. 3: Kadet Wing and Airfoil Fig. 4: Fuselage Side View and Top View 7

8 Table 1: Rating of the Balance (WT7) Component Axial Force Side Force Normal Force Rolling moment Pitching moment Yawing moment Rating 25 Kgs 25 Kgs 50 Kgs 200 Kgcm 500 Kgcm 250 Kgcm Fig. 6: Axes System 8

9 Table 2: Contents Sr N Configuration Table No. Page No. Figure No. Page No. Alpha Sweep, Beta Constant 1 IIT_MAV basic\run 8\ IIT_MAV basic\beta +10\run 14\ IIT_MAV basic\beta +5\run 15\ IIT_MAV basic\beta -5\run 16\ IIT_MAV basic\beta - 10\run 17\ Alpha constant, Beta Sweep 6 IIT_MAV basic\aoa - 5\run 18\ IIT_MAV basic\aoa 0\run 19\ IIT_MAV basic\aoa +5\run 20\ IIT_MAV basic\aoa +10\run 21\ IIT_MAV basic\aoa +15\run 22\ Elevator deflection, Alpha sweep, Beta constant 11 iit_mav basic\el +5\run 7/ iit_mav basic\el= -5\run 9\ IIT_MAV basic\el= - 10\run 10s\ IIT_MAV basic\el= -15\run 11\ IIT_MAV basic\el= -20\run 12\ IIT_MAV basic\el= -25\run 13\

10 Aileron deflection Alpha sweep, Beta constant 17 IIT_MAV basic\al L+15, R- 15\run 29\ IIT_MAV basic\al L+10, R-10\run 30\ IIT_MAV basic\al L+5, R- 5\run 31\ IIT_MAV basic\al L-5, R+5\run 32\ IIT_MAV basic\al L-10, R+10\run 33\ IIT_MAV basic\al L-15, R+15\run 34\ Rudder Deflection Alpha sweep, Beta - constant 23 IIT_MAV basic\rudder - 15\run 23\ IIT_MAV basic\rudder - 10\run 24\ IIT_MAV basic\rudder - 5\run 25\ IIT_MAV basic\rudder +5\run 26\ IIT_MAV basic\rudder +10\run 27\ IIT_MAV basic\rudder +15\run 28\ Tare test 29 IIT_MAV basic/less wing/tare test/run 3/ IIT_MAV basic\less wing, LG\run 4/

11 Fig 7 11

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47 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\run 8/ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 3 47

48 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\beta +10\run 14\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 4 48

49 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\beta +5\run 15\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 5 49

50 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\beta -5\run 16\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 6 50

51 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\beta -10\run 17\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 7 51

52 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\aoa -5\run 18\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 8 52

53 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\aoa 0\run 19\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 9 53

54 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\aoa +5\run 20\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 10 54

55 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\aoa +10\run 21\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 11 55

56 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\aoa +15\run 22\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 12 56

57 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el +5\run 7\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 13 57

58 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el= -5\run 9\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 14 58

59 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el= -10\run 10s\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 15 59

60 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el= -15\run 11\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 16 60

61 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el= -20\run 12\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 17 61

62 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\el= -25\run 13\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 18 62

63 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\al L+15,R-15\run 29\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 19 63

64 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\al L+10,R-10\run 30\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 20 64

65 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\al L+5,R-5\run 31\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 21 65

66 AERODYNAMIC CHARACTERISTICS - KADET, CASDE IITB CONFIGURATION = : iit_mav basic\al L-5,R+5\run 32\ REFERENCE AREA (Sq.MT) = : REFERENCE SPAN (MTS) = : REFERENCE CHORD(MTS) = : DISTANCE OF MOMENT REF. POINT FROM FUSELAGE NOSE FROM FUSELAGE NOSE (MTS) : FROM FUSELAGE REFERENCE LINE (MTS) : FROM BALANCE CENTRE (MTS) : BODY AXES AOA BETA VELOCITY Dyn.Prs CZ CX CY CM CL-R CN WIND AXES AOA BETA VELOCITY Dyn.Prs CL CD CY CM CL-R CN Table 22 66