1. Propulsion PDR 1 Team #3 Presented by: Greg Davidson Etan Karni
Colleen Rainbolt

2. Propulsion Selection Process
Obtained Fall ’02 propulsion design code to select optimum motor from database
Motor database (brushed only) created from Motocalc data
72 motors in database
Obtained Gold.m code for propeller analysis
Integrated Gold.m into Fall ’02 code

3. Motor Analysis—Prop ‘02 Code execution steps Modifications
Aircraft operating point
Optimal prop size
Motor operating point
Gear ratio
Battery analysis
Modifications
Propeller analysis using Gold.m
Automatic evaluation of complete motor database

4. Propeller Analysis—Gold.m
Uses Blade-Element theory to analyze an arbitrary propeller
Propeller analysis based on Clark-Y airfoil

5. Propeller Trade Study: =0.6

6. Propeller Trade Study: =0.8

7. Propeller Trade Study: =1.0

8. Propeller Trade Study Results
Pitch
Ratio
Propeller Diameter
Propeller
RPM
Power Required
0.6
11.4 in.
3760
28.0 W
0.8
9.3 in.
4610
29.9 W
1.0
8.1 in.
5280
31.8 W

9. Selected Propeller Properties
Diameter
11.4 in.
Pitch
6.8 in.
RPM
3760 RPM
Chord
0.6 in.
Reynolds Number
~100,000

10. Optimum Electric Motors
Top 5 motors from database
Graupner Speed V
Mabuchi RS-550
Mabuchi RS-380
Multiplex Permax 7.2V
Multiplex Permax 6.0V
Graupner motor selected on the basis of cost and availability

11. Graupner Speed 400 Rated horsepower .055 hp Motor efficiency 72%
Motor constants
Kv = 2332 RPM/V
Kt = 0.58 In-oz/amp
R = Ohms
Io = 0.5 Amps
Rated number of cells
6 NiCad or 2 Lithium
Rated voltage
7.2 V
Price
$9.50 (Hobby Lobby)

12. Selected Gearbox Gear Ratio 4.09 : 1 Efficiency 85% Price
$11.90 (Hobby Lobby)

13. Future Considerations
Confirm validity of this propulsion system choice
Closely matches what is already in the sizing/constraints code
Modify weights code to include fixed propulsion system weight
Perform more in-depth analysis of propeller on and off design point

14. Questions?