View Full Version : Retro Hawk motor heat sink/comm cooler?

02-13-2016, 08:01 AM
Hi Guys,
Does anyone have any experience with using one of those clip on heat sinks and/or commutator coolers ( like the ones from Trinity/Epic "Evil Bucks Racer") on a Hawk Retro motor? Looks like they are IRRA legal.

I don't see them used much really, which probably answers my question right there.

Just curious if the reason they aren't used much is because these devices are simply not all that effective, or the heat build up on the Retro Hawks doesn't effect the performance enough to warrant the additional weight on the car and rotational mass on the end bell side arm?

Any advice or experience anyone has is much appreciated.


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02-13-2016, 02:31 PM
My opinion may not be shared by others who have tried them. The comm coolers add flywheel mass to a motor which needs more braking action and the clip ons add more top heavy mass to impede handling. It is not MUCH mass, but keeping the mass low and as little as possible seems to work better. If you have a hot running motor, you probably have too much friction, mass or trying to get too much speed out of the gearing - too tall a ration.

A different application may give different results.

02-13-2016, 07:10 PM
I tried one a few times. It didn't seem to make any difference so I stopped using it.

Its better to cut that end bell side armature shaft as short as possible.
Its less mass that the motor has to spin. But don;t tell anyone..:)

02-13-2016, 10:50 PM
Thanks for your input guys. Seems like the pros don't outweigh the cons.

Looks like i will just have to improve my driving to gain back that next 0.1 sec. ;)

Thanks again.

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02-14-2016, 11:16 AM
Cutting the brush end of the shaft makes it illegal to race in Sanctioned events since that is an identifier for the 'retro' hawk motor. The shaft weight is too minimal to matter on them.

02-14-2016, 11:23 AM
Yes Sir, I plan to strictly adhere to IRRA. Part of the challenge/fun is to do the best you can within the rules. There are so many variables (within the rules) that can be tweaked in these retro classes.... It's fascinating and addicting!

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