I LOVE my new BF 109 Funfighter, especially on a 4-cell battery. But … the motor and ESC are getting way too hot to suit me. I swapped out the stock 20A ESC for an E-flite 30A ESC, but it really didn’t seem to help.
I think at least some of the problem is the complete lack of airflow around the motor and electronics. I looked closely and there is only the smallest opening in the front of the cowling, large enough for the motor shaft to exit but smaller than the prop spinner in front of it. There are no more vents anywhere, the only holes being the very bottom of the fuselage for the servo wires to pass through.
I’m going to take a two-fisted approach to the problem. First, I’m swapping in a giant HobbyKing SS 40/50 amp ESC with a nice heat sink on top. Upon realizing that my planned 50A ESC didn’t have an onboard BEC, I decided to replace the stock 20A ESC with a 40A Detrum ESC.
Next, I’m going to cut some openings in the front part of the plane, and enlarged the exit hole some additional exit holes toward the rear to try and increase the convective cooling inside.
I’ve also created a small side vent, made from a length of plastic tubing, to hopefully ram more air into the the case.
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- Side vent emerges just behind the battery, across from the ESC.
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- Side vent seen from the top
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- Side vent close-up
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- Side vent finished – glued in place.
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- Plastic tubing cut to shape.
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- Plastic tubing run through the fuselage
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- I significantly enlarged the exit vent on the bottom of the plane.
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- Larger exit vent.
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- I cut a vent on the cowling, above the prop spinner.
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- A big, honkin’ 40A ESC. It barely fits.
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- The motor is completely enclosed with almost no air flow.
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- There are no openings in front of the motor to allow air to enter.
update 6/7/12: I’ve realized the the ESC I was planning on using has no onboard BEC. I have no BECs onhand so it’s either buy a BEC or buy a new ESC. For now, I’m going to see if the increased cooling from the new vents helps any.