S

Steve Brown

Well Known Member
Cleaning the flap motor - question

What are you guys using?

I'm putting my airplane back together today and I may as well clear the motor first. I don't think its ever been cleaned in over 300 hrs.
 
I used tuner cleaner purchased from Radio Shack, figuring it is designed to clean electrical components and has some lubricating properties. I am not claiming to be an expert by any means but it seemed to work well.

BTW: 300 hours is about when mine went belly up from grease contamination. Good luck.
 
Good timing

I just cleaned my flap motor this morning. I had to make my first no flap landing yesterday in quite some time. Shoud probably practice some more but no big deal. It would sure be a lot worse to have them stuck down somewhere. This motor had maybe 300 landings on it since new.

Anyway I used mass airflow sensor cleaner because that's what I had laying around and it leaves no residue. Get a couple of small ty-raps to hold the brush springs back, some q-tips and small tweezers and you're all set. Be careful and don't pinch the o-ring between the motor and gearbox.

Paul Danclovic
Jamewtown NC
RV-8A N181SB
 
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Timely

Last week I was away from home with the flaps stuck down on my '9A. Fortunately the things came back up (healed themselves) after lunch. I've got about 450 hours on the unit in 5 years.

I tore into it today and the motor looks fine (at least until I took it apart). The drive shaft was covered in grease but not the motor since I mounted it motor up. After taking the motor off to inspect I discovered that the shaft is really pretty hard to turn. Not what I expected. I think that the shaft and drive nut is just sticking so that it can't pick up and reverse the travel. Seems to always stick up or down (mostly).

Just curious what others have seen here. I'm replacing the whole unit to get the airplane back in the air, but I wouldn't mind figuring this out for next time.
 
The flaps on my 6A have performed without flaw (150hrs), which I know some have not been able to say. I'd like to keep it that way. For annual maintenance, is there any generally performed lubrication or other maintenance for the flap motor assembly? I know excess grease has been an issue, but maybe a light coat of white grease on the shaft? Or should I leave a good thing alone until it has issues?

Looking for advice on those who have learned from experience:)
 
Flap motor inop

I note many (well, several) notes about having to deal (and re-deal) with our flaps motors. We too have had a recurring problem and the evidence is that it is a brush problem (a whack on the motor with the handle of a screwdriver 'fixed' it last time). So my question is which motor do you have? We have the Pittman and I have talked to their engineering guy. He claims they ship thousands of those motors monthly and there is just no known problem with them such as we seem to be experiencing. I'd like to be better able to give him a more accurate accounting of our 'problems', if any, so if you have had or are having problems with your Pittman flap motor, please let me know. You could email me directly: [email protected]. That way if necessary I could simply forward the accountings of problems to him directly.

Thanks,

David McConnell
 
About the 300 hour mark

Mine started getting intermittent after about 300 hours in service. After they quit working altogether in the up position I took it apart and cleaned the excess grease off with some electronic switch cleaner (don't remember the brand, probably from the aviation isle at Radio Shack) followed by some compressed air, very lightly sanded the commutator contacts with some #600 sandpaper, used the back edge of an Xacto knife point to rake the crud from between the commutator bars and then reassembled it with a small dab of dielectric grease on each end of the shaft. Worked better than new; quieter and smoother and no further problems in over 200 hours of additional use. I think the motors are sound and that some just got assembled at the factory with excessive grease on the main worm screw that tends to migrate into the electrics. (A lot of the grease had worked its way into the commutator/brush area.) Worked for me but YMMV.
 
I've mentioned this before but I think it's worth mentioning again. I've had zero problems with my flap motor and others that have done it this way have had similar results. I attribute this to making sure my flap "system" does not have any unnecessary drag in it. If the motor has to overcome excessive drag from delrin blocks being too tight, it will cause the motor to overheat which then causes the grease viscosity to lower and then the grease gets flung everywhere. I know if you ask Van's they are going to say "it's ok" but I disagree and made my flap system so it moved freely.
Just my 2c
 
Cleaned "in place"

Went down to the local NorthAmerican Aviation Paraphernalia Association (NAPA auto parts place) and got some electric motor/parts cleaning stuff (CRC brand) . $6 can. Sprayed both ends of motor, not even taking it apart. (or pulling it out of the plane) Has now worked for several flights after going totally inop for several.

Do read and heed the warnings on the can. Pretty nasty stuff you don't want on your paint or in your eyes or lungs.
 
I guess we just clean 'em.

After reading and re-reading the posts here, and after discussing our problem with the manufacture (Pittman), here are my conclusions. Pittman tells me (and I have no reason to disbelieve them) that they ship thousands of these motors monthly and our problem is no known problem in any other application. From that I hypothesize that our problem stems from the mating of the motor with the jackscrew and the jackscrew's habit of forcing grease up into the motor. I know that the first time we had the motor failure I cleaned a significant amount of grease from around the armature, and commutator and brushes. The two times since then that I have cleaned the motor the brushes and commutator were very dirty - I now assume that I was not aggressive enough in removing the guck (technical term) so this last time I soaked the brush carrier plate in MEK, used scotch bright on the commutator and a pick to clean out the gaps between the commutator segments. We shall see how that all works out.

Just a comment on the successful trouble-free flights. I think it takes about 10 seconds for the flaps to deploy fully. Assume half-hour flights, three hundred hours of flying means the flaps were fully deployed 600 times for about 6,000 seconds, or 100 minutes - a bit over an hour and a half. I don't think that is anywhere near the trouble-free operation we should expect from those motors, especially as an intermittent operation where heat should not be a factor.

Thanks to all who are helping with finding a permanent solution to this irksome problem.

David
 
I am going to take a good look at my future flap motor (not bought yet) and I am going to do some preventative maintenance to the motor before the device is finally fitted. Assuming a 100 minute operation cycle over three hundred hours flight time, these motors are failing very very early. I suspect that Silver Fox is correct in his assumption that the screw jack is causing crude to migrate to the commutator area of the motor.
 
This is a task I need to do again at condition inspection for preventive since they stuck momentarily yesterday. Seen this before. Use grease sparingly.
 
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