Flap Circuit Pops
 

Hi Everyone -

In flight, my flap 10 amp circuit pops on anything past 1/3. Works fine on the ground. So I do most of my landings at 1/3.

Any ideas? Circuit was replaced. Motor tired? Anyone rebuild them?

Thanks,

Bryan

My 2 cents:

There is a much greater load on the flap motor in-flight than on the ground.

Could be:
1. Weak 10 amp circuit breaker
2. Weak motor drawing too many amps
3. Flaps out of alignment or needing lubrication
4. Sticky push-pull control cable
5. A short in the wiring somewhere, including the selector switch

Try to duplicate the issue on the ground by having someone place some resistance on the flaps when lowering. Nothing crazy, but enough force to somewhat simulate airflow.

If you are able to duplicate it, the problem is likely 1, 2, 3 or 4.

If you are not able to duplicate it on the ground, then I would suspect a loose wire that airflow is somehow causing a short, problem #5.

Do the flaps move at all beyond 10 degrees while in flight, or does the breaker pop exactly at the moment you select the next flap level?

You can put a meter on either side of the breaker and read the amps as you run the flap motor. You will have to remove the breaker cover to do so. If the amps are close to 10 while on the ground, they are for sure over 10 while in the air.

Here is a thread you should look at: http://www.337skymaster.com/messages...landing+always

Thanks MSHAC


Well today we did what you suggested and was able to replicate the pop by putting some resistance on the flaps. Indeed popped anything past 1/3.

Breaker has been replaced. I'm now leaning toward the motor. My airplane is a 1969 337D 337-1161. I think the motor is C301001-0504 or C301001-0902.

Do you think they still make this motor new. I can't seem to find it.

Thanks!

Still may not be the motor. You really should check the amps while operating the flaps. If you've already changed the CB, you know how to get access for the test.

Before I bought a new motor I would disconnect the motor and operate the flaps manually to be certain there is no binding.

Flap motor assembly is shown below.

Attachment 2937

Also a link to a photo: https://baspartsales.com/c301002-020...assy-volts-28/

MSHAC -

It was the motor. Installed a "new to me" one, flew and everything worked great.

It now takes 6 seconds to extend and retract vs 10, sounds much better and no circuit pop!

It was a 30min swap!

The rotor had too much play and was grounding (contacting) the case on one side.

Thanks for your help and conversation.

Bryan

Very happy you got it fixed! I'm pleased I could be of some service to you.

Cheers! :D