1. Patrick Dempsey Bridget Fitzpatrick Heather Garber Keith Hout Jong Soo Mok Propulsion Preliminary Design Review #2 October 17, 2000

2. Motor Evaluation -Minimum required values to complete the mission Power = 125W Thrust at climb = 3.36 lbf Thrust at turn = 2.80 lbf -Run motor test code using the motor constants supplied by the manufacturer.

3. Motor code -Values input into the code For Motor Vin = voltage * cell # Motor constants – Kt, Kv, Rm, Io Inet = Iin-Io Pin= Vin*Iin Tout=Kt*Inet Pout=Inet*(Vin-Iin*Rm) RPM= Kv*(Vin-Iin*Rm)

4. Motor Code Eta=Pout/Pin Istall = Vin/Rm Imax= sqrt(Io^2*Istall) Etamax= ((Imax-Io)/Imax)^2 For Gearbox: given values-gear ratio (m), Eta g RPM g =RPM/m Pout g = Pout/Eta g For Speed Controller: given value-Resistance(R) Pd = Iin^2*R

5. Motor code Pin sp =Pout B =Pin+Pd Pout sp =Pin Eta sp = Pout sp / Pin sp -Choose the best motor based on Power output and Efficiency. -Select optimal condition

9. Astro Cobalt 25 at 19.2 Volts

10. Aveox 1415/1.5 at 19.2 Volts

11. Aveox 1415/2 at 19.2 Volts

12. Maxcim N32-13D at 19.2 Volts

13. Maxcim N32-13Y at 19.2 Volts

14. Motor Selection Motor : Maxcim N32-13Y Voltage : 19.2 V Current : 16 A Efficiency : 90.408% RPM : 25946.24 Pout : 277.7344W Tout: 14.3792 in-oz

15. Gearbox and Speed Controller Selection Gearbox -Efficiency : 95% -Gear Ratio : 3.7 -Pout g : 263.8477A Speed Controller -Efficiency :99.29% -Resistance : 0.009 Ohms -Pout sp :307.2 W -Pin sp : 309.504W

16. Propeller Analysis Tool : modified Gold script Method : Run at various diameters and pitches Match Power and Thrust Get value for J = V/nD, Cp, and Ct Calculate Power from Battery P B = Pr/(Eta s *Eta m *Eta g *Eta p ) Calculate Energy required for Battery E = P B *t

17. Propeller Analysis P B from Motor Code >= P B from Calculation E est = P B *2min. + 3/4*P B *10min. <= E

18. Propeller Selection and Power Matching Results from modified Gold Script

19. Advance Ratio Versus Efficiency

20. Advance Ratio Versus Cp and Ct

21. Propeller Selection and Power Matching Propeller : 14” Diameter and 10” Pitch P B Calculation(Gold) = 278.77 W P B from Code (Motor Code) = 309. 504W Endurance time =12 min. E= 3345.12 W-min. E est = 2648.315 W-min.

22. Questions?