DIY RC outrunner cooling fans

[spinningmagnets]

Now that there has been a greater variety of motors made available for non-hub E-bikes, the use of RC outrunners on E-bikes seems to be declining (80-85 / 80-100's). With the sales of the 80mm diameter Turnigy's down, fewer suppliers are stocking them. However...RC outrunner use in stand-up scooters and powerboards is increasing, and shows no sign of slowing down. Those applications are a place where the higher expense of a tiny RC ESC may be worth it (compared to a much larger 6-FET).

Also, there's no reason these can't be 3D printed, but I'll leave that to the younger members to sort out, bearing in mind that the popular motors for these jobs are the 50mm and the 63mm. I'm starting this thread to make the DIY fan methods easier to find in the future.

This original series of posts is from master hot-rodder Thud, but it is buried in the middle of the "rewinding" thread. For the new ES posters who join every day, and don't know who he is...A few years ago there was a gas-powered bicycle race in Arizona that was going to allow electric bikes to participate, so some old guy from Michigan decided to:

Weld up a custom race frame with 20-inch wheels
Design and build a custom robust 2-speed transmission for it
Find a motor that is a good size, then rewind it to a more optimum Kv and Wye termination
Figure out how to add hall sensors to it
make a fan for it so it would run cooler in the race, and then...

He published all this information with pics to make the info available to everyone (http://endless-sphere.com/forums/viewtopic.php?f=28&t=13731). This pic series shows him making a wooden prototype, then using that to create a silicone mould, then using that mould to pop out cast plastic fans very easily and cheaply.

"Re-wind of a turnigy 80/100 (Now-tutorial w/Video)"
http://www.endless-sphere.com/forums/viewtopic.php?f=30&t=20618&start=250#p590501

Here is an example of the optional fan for the high-end Astro motors, which was cut by an expensive CNC process. This centrifugal shape is a well-proven design.

 

[spinningmagnets]

For those who may have doubts, because..."I suppose it helps, but...is it better enough to be worth the trouble?"

Here is a data log that shows under heavy use, an 80-100 ran 20C cooler (68F). This is from a simple part that is cheap, light, and will not wear out or require any fiddling with (unlike water-misting, or a water-cooling jacket with pump, or an electric-powered fan...)

http://endless-sphere.com/forums/viewtopic.php?f=30&t=44287&start=15#p675803

I also plan to try this on the disc brake side of a hub motor. ES member bluefang has done this to a scooter hub that has been adapted to be a non-hub. Intake holes on the perimeter to flow across the stator coils, and exhaust holes near the axle on the disc brake side

 

[Ratking]

I've been thinking a lot about a fan on the 80-100 as well, the best solution would be a combined fan and end bell/cap (does this word make any sense?)
Should not be any problem with a quality CNC machine either. I don't have any space for an extra fan bolted to the end of my motors, but an integrated one would work just fine.

 

[spinningmagnets]

Yes, a fan of this shape could be mounted to either end of the motor, as long as it was attached to the spinning part....