M20K 252 Cowl Flap Motor

[RussG]

Does anyone by chance happen to know the specific dimensions to the screws that hold the motor onto the gear side of the actuator.  Mine decided to separate after vibrating 3 of them away. Thanks for any help. 

[Will.iam]

I remove the cowl flap arms from the cowl flap then i switch the cowl flap switch to closed and let the electric motor move them up out of the way. When i re install the lower cowl i then switch the cowl flap switch to to open and let the motor lower the connector arms back down. Then just reattach the arms to the cowl flap. Keep me from banging the arms on the cowl as i install it. 

[Guest]

3 hours ago, RussG said:

Does anyone by chance happen to know the specific dimensions to the screws that hold the motor onto the gear side of the actuator.  Mine decided to separate after vibrating 3 of them away. Thanks for any help. 

If you have a micrometer, measure the thread diameter then search “SAE screw thread size chart” to figure it out.  I’d guess #4-40 which is also the size that holds the motor to the airframe.

Clarence

[carusoam]

And probably a touch of blue thread lock to go with that?

PP guess, regarding screws vibrating out...

Best regards,

-a-

[Don Bishop]

This thread save me a ton of money and effort.  

My cowl flaps stopped working.  Thinking about the oil and where the filter is, having oil contaminate the motor made sense.  With the power to the plane off, I simply sprayed contact cleaner onto, into, and around the motor.  Sure enough, the runoff had oil in it.  I noticed that the silicon that protects the connections to the micro switches had degraded, so I sprayed more contact cleaner into that area and more oil came out.  I let the contact cleaner dry and applied power.  Voila!  Motor was back in business!  I applied high heat silicon to the connections to seal them back up and put the cowling back on.  Everything is working perfectly.

[Will.iam]

1 minute ago, Don Bishop said:

This thread save me a ton of money and effort.  

My cowl flaps stopped working.  Thinking about the oil and where the filter is, having oil contaminate the motor made sense.  With the power to the plane off, I simply sprayed contact cleaner onto, into, and around the motor.  Sure enough, the runoff had oil in it.  I noticed that the silicon that protects the connections to the micro switches had degraded, so I sprayed more contact cleaner into that area and more oil came out.  I let the contact cleaner dry and applied power.  Voila!  Motor was back in business!  I applied high heat silicon to the connections to seal them back up and put the cowling back on.  Everything is working perfectly.

What brand of high heat silicon spray did you use?

[carusoam]

Great pirep/follow-up Don!

Best regards,

-a-

[smwash02]

On 3/7/2021 at 4:14 PM, M20Doc said:

If you have a micrometer, measure the thread diameter then search “SAE screw thread size chart” to figure it out.  I’d guess #4-40 which is also the size that holds the motor to the airframe.

Clarence

@RussG, you've probably figured it out by now, but square top with the shaft to the gearbox are #4-40 and the gearbox to the motor are #2-56. The ones from the mount to the square top are #4-40 100 degree tapered.

Edited May 2, 2021 by smwash02

[RussG]

Thank-you. Mechanic was able to get it all squared away and working again.  Thanks again. 

[Jay Aranha]

On 11/2/2014 at 8:09 PM, Encore Driver said:

I've read this thread with interest since I have a question about my cowl flap motor. The motor works but does not hold position. It slowly bleeds off to about half open unless I select full closed or full open. I have to reset it about every 10 minutes in flight to keep the oil temp where I want it. Is this normal for this system or should I have it rebuilt?

Steve

@Encore Driver, I have the same problem on a new “rebuilt” motor from globe so hoping it’s a setup/adjustment issue. Mine creeps open about 1/3 on its own unless I leave it in the closed position so the motor holds it against the closed switch. 

[Ragsf15e]

On 10/27/2022 at 2:35 PM, Jay Aranha said:

@Encore Driver, I have the same problem on a new “rebuilt” motor from globe so hoping it’s a setup/adjustment issue. Mine creeps open about 1/3 on its own unless I leave it in the closed position so the motor holds it against the closed switch. 

Did you get this figured out?  I also have the newer cowl flap motor and have the same issue (slowly creeping open in flight).  Would love to know how others solved it.

[Z W]

17 hours ago, Ragsf15e said:

Did you get this figured out?  I also have the newer cowl flap motor and have the same issue (slowly creeping open in flight).  Would love to know how others solved it.

Before you let them pull the cowl flap motor and send it for rebuild, I would remove the upper and lower cowl, get a helper, and have them run the motor from open to closed several times while you watch the mechanism. It's a simple enough system and it sounds to me like something is dirty, binding, or mis-adjusted. You could also try to pull the mechanism open gently by hand to see if the motor is slipping internally. 

I have the 252 style cowl flap motor and it was sticking closed in flight. It would eventually open but only after the switch was left in the open position for approximately 60 seconds. Could not duplicate the problem on the ground.

A&P replaced the cowl flap motor after I gave him the info for Globe from this thread. When the new one came back, it did not fix the problem. What did fix it was thoroughly cleaning and re-lubricating the arms and cable that open and close the cowl flap. I did this by spraying it out with WD-40 to clean, then Tri-flow to lubricate, while someone else in the plane opened and closed the motor several times. Quite a bit of dirt and gunk came out. The flap now opens and closes smoothly and more quickly than it ever has.