AAE 451 AERODYNAMICS PDR 2 TEAM 4 Jared

AAE 451 AERODYNAMICS PDR 2 TEAM 4 Jared Hutter, Andrew Faust, Matt Bagg, Tony Bradford, Arun Padmanabhan, Gerald Lo, Kelvin Seah November 18, 2003

OVERVIEW n Concept Review n Aircraft CL and CM n Updated Wing Size n Aircraft Plots n Follow-Up Actions TEAM 4

TEAM 4 CONCEPT REVIEW Empennage Horizontal and Vertical Tails sized using modified Class 1 Approach (per D & C QDR 1) High Wing S = 47. 8 ft 2 b = 15. 5 ft, c = 3. 1 ft AR = 5 Twin Booms Avionics Pod 20 lb; can be positioned front or aft depending on requirements Twin Engine 1. 8 HP each 3 ft apart; 7. 3 ft from Wing MAC to HT MAC

TEAM 4 AIRCRAFT LIFT COEFFICIENT n Lift Coefficient CL = CL * + CL e* elevator + CL 0 Matlab script based on Roskam Vol VI Ch 8: CL = 5. 41(rad-1)* + 0. 4675(rad-1)* elevator + 0. 3086 Predator Codes from AAE 565 CL = 5. 473(rad-1)* + 0. 454(rad-1)* elevator + 0. 3113

TEAM 4 AIRCRAFT PITCHING MOMENT n Moment Coefficient CM = CM * + CM e* elevator + CM 0 Matlab Script based on Roskam CM = -2. 0496 (rad-1)* + (-0. 1771)(rad-1)* elevator + 0. 0425 Predator Codes CM = -2. 2682 (rad-1)* + (-1. 058)(rad-1)* elevator - 0. 2785

TEAM 4 AIRCRAFT CL AND CM n AAE 565 Predator code similar to Roskam n Roskam uses graphs in his book n Predator has the graphs hard coded into the program n Predator will be more accurate Update Constraint Diagram n Need Maximum CL for Constraint Diagram n Roskam Code solves for Maximum CL n . 06 difference between Roskam Code and Predator for CL

TEAM 4 MAXIMUM LIFT COEFFICIENT n n n Need section cl along wing span Increase Angle of Attack and find new section cls Repeat until the wing begins to Stall That is the stall angle Integrate section cl’s to find Maximum CL

TEAM 4 AIRCRAFT CL AND CM n Three Major Codes: Predator, CL max, and Constraint Diagram ¨ Predator: n n Input: Aircraft Geometry Output: CL and CM equations ¨ Maximum n n Input: Main Wing and Horizontal Tail Geometry Output: CL Max and Alpha at CL Max ¨ Constraint n n Lift Coefficient Diagram Input: Flight Conditions, CL at 0 Alpha, CL max, Engine Info Output: Wing Area and Required Power

TEAM 4 AIRCRAFT CL AND CM n n n Iterative loop can be used Used old constraint diagram values for initial guess Used Wing Area as the Control variable Predator Code Constraint Code Max CL Code

TEAM 4 AIRCRAFT CL AND CM n Lift Coefficient CL = CL * + CL e* elevator + CL 0 CL = 5. 931(rad-1)* + 0. 59(rad-1)* elevator + 0. 2809 n Moment Coefficient CM = CM * + CM e* elevator + CM 0 CM = -3. 6947(rad-1)* + (-1. 058)(rad-1)* elevator -. 3956 Reduce CM 0 for clean flight

TEAM 4 AIRCRAFT CL AND CM CM 0 main contribution is from the Incidence angle of Horizontal Tail (-2. 51 degrees) n Using the Iterative Loop, ran over a range of Horizontal Tail Incident angles n Found Incident Angle that reduced CM 0 the most n

TEAM 4 AIRCRAFT CL AND CM n Lift Coefficient CL = CL * + CL e* elevator + CL 0 CL = 6. 0339(rad-1)* + 0. 6201(rad-1)* elevator + 0. 4237 n Moment Coefficient CM = CM * + CM e* elevator + CM 0 CM = -4. 0421(rad-1)* + (-1. 058)(rad-1)* elevator + 0. 00 Incident Angle=. 23 degrees Does not seem right, may be caused by Downwash from the Main Wing

TEAM 4 AIRCRAFT PARAMETERS n n Wing Area= 34. 5 ft^2 Wing Span= 13. 1 ft Max CL= 1. 8034 @ 12. 88 Degree Angle of Attack CD=. 0339 @ 0 Angle of Attack

TEAM 4 TRIM DIAGRAM AT CRUISE CL=. 4327

TEAM 4 Drag Polar Based on Roskam Vol VI Ch 4

FOLLOW-UP ACTIONS TEAM 4 n Verify CD calculations n Triple Check CM 0 and Incident Angle of the Horizontal Tail n React to changes from D+C, Propulsion, and Structures

AAE 451 Questions?

TEAM 4 Appendix Lift Curve Slope CL = f(CL W, CL HT, w) HT = Ratio of dynamic pressure. Mostly caused by propeller wash and velocity Downwash, w = Caused by main wing’s vortex flow on tail. Changes effective angle of attack for the tail. Negative Positive

TEAM 4 AIRCRAFT PARAMETERS n Lift Curve Slope for Elevator Deflection CL e = f(elevator size, horizontal tail planform) n Zero Angle of Attack Lift Coefficient CL 0 = f(CL 0 W, CL 0 HT, incident angles) HT = Ratio of dynamic pressure. Mostly caused by propeller wash and velocity Incident angles are for both main wing and horizontal tail

TEAM 4 AIRCRAFT PARAMETERS n Moment Coefficient CM = CM * + CM e* elevator + CM 0 CM = -0. 0225(deg-1)* + (-0. 0027)(deg-1)* elevator + 0. 0280 n Moment Curve Slope CM = f(d. CM/d. CL, CL) d. CM/d. CL = f(CG, Aerodynamic Center of Aircraft)

TEAM 4 AIRCRAFT PARAMETERS n Zero Angle of Attack Moment Coefficient CM 0 = f(CM 0_W, CM 0_HT [both about the CG]) LIFT Aerodynamic Center WEIGHT