Flipsky 200A FSESC + 500kv motor / 5:1 gear - ERPM?

EFOIL.builders Electronics (ESC, remote, batteries)
#1

Hope someone more clever than me can figure this out.

My setup is this:
SSS 56104 500kv motor + 5:1 Neugart PLE40 gear
Flipsky 200A FSESC
Flying Rodeo propeller
12S LiPo

Correct me if I am wrong please, but the calculated the max. erpm for my setup is:
12S x 4.2V x 500kv x 6poles = 151.200 erpm (Max. battery cell voltage 4.2V)
12S x 3.9V x 500kv x 6poles = 140.000 erpm (Battery voltage 3.9V under load)

But the max. erpm in the VESC is 100.000 erpm, it cannot but set higher… So am I missing the upper 40.000 to 50.000 erpm or will propeller never reach that many RPM in the water?

100.000 erpm / 6 (poles) / 5 (gear) = 3.300 rpm for propeller
140.000 erpm / 6 (poles) / 5 (gear) = 4.600 rpm for propeller

Link to Metr Pro log from yesterday:

1 Like
#2

Formula correct but used with pair of pole so , 6 poles have 3 pairs , use 3

500kv geared is still ok , past 700kv no if 100k erpm is the limit

On paper max driven rpm : 33k for 56mm and 50k for most 40mm

#3

Do you use watercooling ?

#4

Ohh, so the poles is calculated by pairs. That makes a huge difference. Then it makes sense that I am hitten around 50k erpm at the moment, Max. erpm is that around 70-75k. Thank you Alex.

#5

Yes, with Cheap AliExpress 12V pump.

#6

You say you fitted a correct FR propeller? On a Sss 56104 with gearbox? What shaft diameter did you mount at the output of the gearbox ?
Thanks

#7

I have a 8mm axle, with a coupling between gear and axle. Then i have a 8-12mm hollow shim/tube to fit the FR prop on the axle and M8 thread at the end of the axle, To secure the prop against the pin and thrust bearing. Works perfectly, very little noise and rattle at full rpm in Air.

#8

Thank you is it possible to have more detailed info ( pictures ), because I have the same propulsion assembly as you and would be very interested to mount a FR propeler
Thanks

#9

image image
image
Does this make sense?

#10

Yes thank you, the spacer is a 3D printing ?

#11

Yes, in super strong polymax PLA

#12

Very interesting guldsteen, nice work!
Can you tell what your distance is from end of shaft (threaded side) to shaft pin. And from shaft pin to white face of your motorpod? And lastly, the “thickness” of the FR prop (I think the length of your white shim/tube)?

Ur help is much appreciated. With that info I could check if the setup fits on my system.
I have also an SSS56104 engine with 5:1 gearbox. Only think is that I have a 360KV, so not sure if she spins fast enough.