Post by clipper453 on Sept 27, 2008 6:30:09 GMT 1
I bench tested 5 different size propellers tonight using my Amp/Watt Meter and my digital scale, and I thought I would share the results. This was done using a CommonSenseRC E5-M-18 (1500kV) brushless motor, a Z-20 (20A) ESC, and a 3-cell Lipo battery, all of which were installed on my Super Cub.
It should be noted that the speed controller is rated at 20 Amps max, but my motor is only rated at 16 Amps max, which I didn't realize until after looking at the specs: www.commonsenserc.com/product_info.php?products_id=299
Until now, I've been running the recommended prop, which is 7x4SF. My testing showed that at full throttle, I achieved 15.9 oz of thrust, drawing 14.0 Amps. (According to the motor specs, it should provide 24 oz of thrust at 14.5 Amps.) Keep in mind that my setup has some inherent losses built into it, such as the cowling aerodynamics, rolling resistance of the wheels, etc.
Based on the results of my tests, I think I'm going to try flying with the 8x4E prop, which provides 20 oz of thrust, drawing 16.8 Amps at max throttle. At 50% throttle (where I normally fly at once attaining altitude), it provides 9.7 oz of thrust, drawing only 6.6 Amps. In comparison, the 7x4SF prop at 50% throttle provides 8 oz of thrust, drawing 6.2 amps.
- Matt
It should be noted that the speed controller is rated at 20 Amps max, but my motor is only rated at 16 Amps max, which I didn't realize until after looking at the specs: www.commonsenserc.com/product_info.php?products_id=299
Until now, I've been running the recommended prop, which is 7x4SF. My testing showed that at full throttle, I achieved 15.9 oz of thrust, drawing 14.0 Amps. (According to the motor specs, it should provide 24 oz of thrust at 14.5 Amps.) Keep in mind that my setup has some inherent losses built into it, such as the cowling aerodynamics, rolling resistance of the wheels, etc.
Based on the results of my tests, I think I'm going to try flying with the 8x4E prop, which provides 20 oz of thrust, drawing 16.8 Amps at max throttle. At 50% throttle (where I normally fly at once attaining altitude), it provides 9.7 oz of thrust, drawing only 6.6 Amps. In comparison, the 7x4SF prop at 50% throttle provides 8 oz of thrust, drawing 6.2 amps.
- Matt
