[Hellbringer]

I saw a youtube video where a gentleman made a spindle out a motor from an RC Helicopter so i did a little research and if my math is right wow i just want to make sure i am not going crazy.

This motor

Turnigy HeliDrive SK3 Competition Series - 4249-1600kv (500 size heli)

Voltage: 25V max
Amps: 75A max

So 25 * 75 = 1875 * 0.88 for efficiency = 1650 Watts (their specs list it as 1660 Watts)

1650 / 745 <- watts per horsepower = 2.2 HP

^^ did i do all that right??

[wizard]

Never tried an RC motor but is see a few problems. 1. How do you keep it cool. 2. RC is generally an intermittent usage as the batteries only last a few minutes. I'm not really sure the motors are designed to run continuous duty. 3. You need a very high current power supply plus a motor controller.

In any event I think somebody tried to go this route before on these forums. So maybe a search is in order.

[Bl@ckrat]

The motor can run all day long, the problem is end play on the bearings ....

[Hellbringer]

1. How do you keep it cool.

Yes that is a concern when it has the ability to pull 75A but i would guess that it would pull less then 10A at any given time so i think a heatsink and a fan (which you can also buy from these motors) would do the trick.

3. You need a very high current power supply plus a motor controller.

Yes, this is the downfall, a 25V 75A power supply would be about $300 at that point just buy a water cooled spindle and VFD from keling. The only place i can see this being used is on a smaill machine that cannot handle the weight of a bigger spindle but you need the higher horsepower.

the problem is end play on the bearings

The one that i saw on youtube the gentleman took the lower portion of an existing motor and adapted the helicopter motor to it so he was using the bearings from the old motor to deal with the shaft play.

[mactec54]

Hellbringer

There are others using them with no problems, but for the cost, for everything, you could get a Chinese spindle all set to go, for the same money or less depending on how much Hp you want

You can not use the bearings of the motor to do the work of the spindle, the spindle bearing are separate

[louieatienza]

There's a company called LogiCNC that makes a dongle that allows you to control such motors via Mach3.... but you would use this motor to power a spindle like a Sherline or Taig...