The document summarizes flight tests performed on a Cherokee II sailplane to determine its actual flight performance characteristics and compare them to expected values. Key objectives included determining the glide polar, lift-to-drag ratio, aerodynamic coefficients, and stability derivatives. Instruments were calibrated and test flights were conducted to collect data on airspeed, altitude, attitude, and control surface positions at different speeds. Data analysis was then performed to calculate the glide polar, lift-to-drag ratio values, and coefficients of lift, drag, and pitching moment as functions of airspeed and control surface deflections.

1. Flight Test Evaluation of Cherokee II Sailplane Tony Condon Aere 492 December 11, 2008

2. Cherokee II Sailplane Gottingen 549 Airfoil 40 ft wingspan 125 ft 2 wing area 14.4 ft 2 tail area 2.5:1 taper ratio 600 lb weight 6.66 G ultimate load

4. Objectives Determine Glide Polar Determine actual performance Compare to expected performance Find Aerodynamic Characteristics Find Stability Derivatives

5. Calibrate Instruments Airspeed and Altimeter WWII Vintage Constructed Manometer to calibrate Airspeed Used test set to calibrate Altimeter

6. Calibrate Instruments

7. Calibrate Instruments

8. Test Flight

9. Calculate Polar Determine Altitude change on each run Time between start and finish Calculate descent rate Plot descent rate vs speed Calculate L/D ratio at each speed

10. Calculate Polar

11. Calculate L/D

12. Compare

13. Polar Comparison

14. L/D Comparison

15. Find Aerodynamic Characteristics

16. Process C L All variables known, find C L vs V Know δ e vs V Calculate C L α and C L δ Take C L,0 from Lockheed code Find C L vs. α

17. Calculate C L α and C L δ Use pitch attitude and flight path angle change to find change in alpha Use stick position measurements to find change in elevator angle

18. C L δ vs Speed

19. C L vs α

20. C L vs α

21. Process C D Know everything for Weight based C D Use Minimum Sinking condition to find C D,0 , e

22. Process C D

23. C D vs α

24. Process C m δ C m = 0, trim condition Know C m,0 and C m α from Lockheed code Know α and δ e for each speed Find C m δ

25. C m δ vs Speed

26. Future Work Better camera setup Digital Level More accurate stick position Automated processing More glider types!

27. Questions?