HobbyZone Super Cub Prop Tests

Prop selection is to a large degree based on what you expect out of your Super Cub – some data to help out

I set up the Super Cub's receiver and motor on my Home Brew Motor/Prop Tester to test out a number of different propellers using the SuperCub's stock 480 brushed motor. The tests were conducted using the standard 7 cell battery @ 8.4 volts and then with a laboratory power supply.

The props used were to give a range of results, ranging from a 9×4.7 to 11×8 to compare results to the stock Super Cub 10×8 prop.

 

Props

Super Cub Propeller Test Results

Stock brushed 480 motor, 8.4 volt 1000 mah NiMH batteries

 

Propeller

RPM

Amps

Volts

Watts

Thrust in Grams

Grams/Watt

Grams Thrust/RPM (000)

Stock 10×8

4222

9.47

7.85

74.3

402

5.41

95.2

GWS SF 9×4.7

5231

6.18

8.70

53.8

334

6.21

63.9

GWS SF 10×4.7

4972

8.14

8.19

66.7

434

6.51

87.3

GWS HD 10×6

5431

6.86

8.46

58.0

384

6.62

70.7

GWS SF 10×8

4333

9.27

7.87

73.0

404

5.53

93.2

GWS SF 11×8

3800

10.37

7.79

80.8

448

5.54

118.0

After this test, I then used a laboratory power supply to hold the voltage constant at 7.90 volts and let the amps float – the results below:

 

Propeller

RPM

Amps

Volts

Watts

Thrust in Grams

Grams/Watt

Grams Thrust/RPM (000)

Stock 10×8

4196

9.27

7.90

73.2

402

5.49

95.8

GWS SF 10×4.7

4727

7.43

7.90

58.7

402

6.84

85.0

GW HDS 10×6

5121

6.11

7.90

48.3

338

7.00

66.0

GWS SF 10×8

4247

9.04

7.92

71.6

390

5.45

91.8

GWS SF 11×8

3728

10.40

7.74

80.5

440

5.47

118.0

The power supply would only go to 7.74 volts for the 11×8 SF.

The closest alternative to the stock 10×8 is the GWS SF 10×8; however, the blades are not as rigid as the stock 10×8 and in flight under high stress circumstances may not perform up to the stock prop; I've used the GWS SF 10×8 and not noticed substantially different performance.

The most efficient prop is the GWS HD 10×6 – this will give increased flight times due to its lower power requirements.
I think this one is the best alternative to the stock 10×8 – even though the thrust is a bit lower, it is more robust than the SF props and most likely holds its shape better under stress. It also fits directly over the nut on the 480's shaft – the other SF props require a lock washer to hold them in place.

The GWS SF 10×4.7 is puts up some good numbers on the bench; however, I used this and did find that it does not perform as well as the numbers indicate – for example, I found loops a bit of a struggle from level flight. I think this prop flexes under stress and as a result it's losing pitch, resulting in less power.

If you want more power, then the GWS 11×8 is a nice upgrade. I've used this one also and it does give more power but it will cut into flight times as it needs more power.

Last, I tested the 9×4.7 to show the performance difference – I would not recommend flying this one.

CONCLUSIONS

Prop selection is to a large degree based on what you expect out of your Super Cub – if you want longer flight times and good performance, the GWS HD 10×6 looks like good all-around choice. The GWS 11×8 SF is a "power" choice and the GWS HD 10×4.7 could be an interesting one to try out.

Users with the 9.6 volt / Lipo as power sources will show better numbers due to higher power, although without reading amps/volts with a wattmeter, I'd hesistate to guess by how much.

Finally, it's interesting to note that with 400 grams of thrust – 14.1 ounces – the Super Cub's spec thrust to weight ratio is 0.52, about what you'd expect for a trainer.

I would very much appreciate emails from others with experiences with these and other props.

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