Thrust test of 720mm coreless motor with 65mm prop powered by supercapcitor

Motor resistance: 0.8 ohm
Initial peak supercap voltage: 2.83V
Max thrust 12.7g

65mm ACW prop didnt have a hole all the way to reverse it on motor shaft. So a hole was drilled with 0.8mm drill bit in a pin vise. Hole was small for the 1mm shaft of 720 motor so it was enlarged by using the same 0.8mm bit as a file (pushing the bit and out of the hole while pressing it to the sides of the hole).

The ACW prop was reversed and fit on a CW motor which was spun in a CW direction (seeing down from top). This throws the air upwards which pushes the assembly with clay downwards on the scale, thus increasing the force/weight.


2 other tests gave similar results with one test giving 13g which was probably for 2.85V. Thrust decayed to 3g in 25-30 sec in these tests. For my XSticksy C plane, designed by my friend John Haren, the glide ratio is approx 4:1. So for AUW of about 12g it needs 3g thrust to fly level. That means thrust for climb is available for 25-30sec. With my small and not-so-good flying field, this will probably increase chances of flying away and might need less than 2.83V initial charge voltage.

Higher charge voltage will give higher thrust and duration but will probably shorten supercapacitor life. But it would be great to explore full potential in large flying field.

Thanks to Asanga Gunatilake for poating hia video of theust test from where I got the idea of using modelling clay as a simple setup tp do thrust tests.