RC cooling fan, mini reveerse prop .... anyone tried this?

[LI-ghtcycle]

I had an idea given to me at the local hobby shop today, and maybe it's already been said, but what if you had say a friction drive such as a Kepler, and on the prop shaft, you had a small propeller that faced the motor to be used for cooling purposes.

I imagine it couldn't hurt?

 

[amberwolf]

Assuming the motor is spinning in the same direction as in it's typical RC use, you wouldn't want to reverse the prop, though--typically an RC motor used in almost any aircraft application is a puller not a pusher, so the airflow is already in the right direction--from the shaft towards the rest of the motor.

If the motor runs in the other direction, then you'd need to reverse the prop blade angle.

 

[LI-ghtcycle]

Ok, I didn't mean have a counter rotating prop, just something that would cool the motor, anyone tried this?

 

[spinningmagnets]

Centrifugal fans work well whenever its possible to use one. A vented front disc brake is an example. Perhaps find a vacuum cleaner fan? Vac fans come in many different sizes.

The basic principle is that the blades fling the air outwards from the center. You might have to add a plate to enshroud the fan blades (depending on style found) if you get a fan that is the perfect size.

Just an option to think about...

 

[TylerDurden]

IIRC, Bubba ("dontsendbubbamail") made one on his first RC build.

http://endless-sphere.com/forums/viewtopic.php?f=6&t=5317&hilit=fan&start=90

 

[amberwolf]

The basic principle is that the blades fling the air outwards from the center. You might have to add a plate to enshroud the fan blades (depending on style found) if you get a fan that is the perfect size.

The vacuum-cleaner fans work pretty well; it was one option I tested on the treadmill motor back during the first CrazyBike2 motor experiments. Ultimately I went with the alternator fan instead because mounting it was less problematic (requiring only a garden-hose washer to friction-clamp it to the pulley on the shaft, with the other normal washers/etc behind it. The VCs I've had apart that far usually have two blade assemblies, and they are VERY light, so you could have a spare in case the first gets damaged somehow.

 

[spinningmagnets]

I recall Bubba mentioning he was unhappy with the performance of the fan he tried. Its an axial, like a prop (thanks for the pic link) so, it remains to be seen if a centrifugal will be any better or not. I am a few months away from trying that. I will try to pick up a pistol thermometer and scale the "hill of death" with-and-without a centrifugal fan.

 

[LI-ghtcycle]

It makes sense to have some sort of shroud, I'm thinking cylindrical just a 1/4 inch larger around than the motor covering the fan blade with both ends open to maximize air flow, maybe even a venturi at the intake on the far side of the fan opposite the motor.

 

[mr.electric]

I think modern plug-in drills have centrifugal fans. The drill case surrounds the impeller to allow air to get sucked through the motor properly.

 

[LI-ghtcycle]

Yes!!! You are correct, that makes a lot of sense! I believe I have one that I can use thanks for the idea!

 

[dontsendbubbamail]

I recall Bubba mentioning he was unhappy with the performance of the fan he tried. Its an axial, like a prop (thanks for the pic link) so, it remains to be seen if a centrifugal will be any better or not. I am a few months away from trying that. I will try to pick up a pistol thermometer and scale the "hill of death" with-and-without a centrifugal fan.

You are correct in that I was never very happy with any of the fan designs I tried. I also tried putting the motor in a tube to pull air around the motor and a centrifugal fan, but didn't seem to get significant improvements in cooling. In the past, some folks have reported excellent results when they add a fan. I just have not been able to achieve similar results.

Bubba

 

[LI-ghtcycle]

Thank you for this information, I will instead pursue a "jacket" that cools the body of the outrunner (stationary side) with water. I might also trade-in my Phoenix ICE 100 for a similar rated ESC with a water jacket.

 

[bandaro]

so out of curiosity for my own build, what methods were found to work best? what didnt work? i was thinking of cutting a pc fan down to glue inside the end of my turnigy to suck air through the motor and out the back, thoughts on this?

also, i was warned about shit getting into the motor so all fans will have to blow air out the back of the motor right? or is stuff going into the motor not an issue?

 

[LI-ghtcycle]

Oh, hello, I think I found something here ... it's a fan specifically designed to cool outrnners being used in heli's!

http://www.pulsosystem.com/motor/cooler.html

Now if I can just get one for my 63 - 74! 8)

 

[ev_nred]

woudnt a cpu fan work? and if so would that hlep make sure you dont blow a esc? sorry if i am hijacking the thered

 

[LI-ghtcycle]

No, not at all, I welcome any and all ideas!

I would prefer a fan that is simply attached to the outrunner motor's shaft rather than a separate fan. I could use any number of small electric fans, but I don't think there are any that would really suit my needs, and would just add more things to break down.