motor cooling between heats

[PDM1]

Hi Monty, I run box12 every week and we run 3min on and 3 min off. Between heats I put my car on a strong fan and cool the motor and by the time the car goes back on the track it is cool. Many of the racers, (these guys went to the Div 1 nats) hook the car to a power supply between heats and run it at 3 volts. They say this cools the motor better than using a fan.

This doesn't make sense. Running a motor on 3 volts with a current draw of at least 3 to 4 amps means 9 to 12 watts of power, which means heat. Plus the motor still seems to be warm when done. I'm told that everybody did this at the Nats.

Enquiring minds want to know, what's the best way to cool between heats.

Thanks
Paul Mascenik

[Slik]

Not to post before Monty but, I think I know this one, maybe Monty a can clear it up (Sorry Monty).

We have a few wing racers where I race, Harter, Acello, Burger. Ive heard of the power supply thing in between heats, I heard they do it so the com does not get exposed to the air, and erode? The com keeps turning, there for keeping it very clean and fresh, thats a extreme way I believe. I cant see why this needs to be done...

[Bobhardt]

I cant believe that the board administrator jumped in on this before letting Monty have a crack at it. So much for setting a good example for the rest of the boys Slik:)

[raceready]

Paul,dont you beat these guys your talking about......Maybe they need to do what you do?Henry has your chassis looking nice,he showed it to me tonight

[Monty @ B.O.W.]

Paul,
Believe it or not, I don't do ANYTHING between heats to cool a motor. If its too hot after a heat, you've been geared wrong, bogged, or bound up - conditions you need to find and fix!
The practice you describe at the Nats is not done to cool the motors, but rather is an attempt to clean the comms and or remove crystallized deposits from the end of the brushes. Its something you might do if you've bogged the car, have that condition fixed, but don't want to change motors for some reason or another. I see it done more with Gr27 or 7 motors here in the West, where we don't try to overload our boxstock motors. I've had running arguements about gear ratios with certain East coast racers for years... we agree to disagree, but all I know is that we use fewer motors and don't worry as much between heats.
I've always believed that the motor gets to its normal operating temperature within a few laps. This temperature is an 'equilibrium point': a constant set by the power being dissipated vs. the cooling action of air passing through the motor. There's lots of ways to reduce normal operating temperature, from the aforementioned lower gearing, to tighter springs, looser body, narrower tires, less glue, lower timing, cleaner braid, etc. What you will definitely find if you can lower that operating temperature, is that your motors will maintain speed deeper into a heat, or maybe not slow down at all for a few heats. I personally believe its better to run 2.85 the whole heat than start at 2.80, finish at 2.98, and be looking to change already!