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FlyingMonkey

Flaps Issue

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Flying yesterday, I had some strange behavior from my flaps.  The following only happened in flight, going from 0° to 15°, or from 15° to 30°:

1)  The flaps would deflect downward, and the flaps would make the normal whirring noise. 

2) The flaps would stop about 2/3 of the way through their travel, and the whirring would stop.

3) About 2-3 seconds later there would be another short whirring and the flaps would reach their full travel and stop.

I checked the display, and it would continue flashing until the flaps finally stopped at their full normal deflection. 

The flaps cycled normally on the ground, and had no trouble retracting normally.  Because of this, I'm thinking the motor might be failing and having trouble generating enough force to more the flaps all the way against the air stream, so it's pausing and then trying again.  It could also be a loose wire between the controller or power source and the motor.  I'm hoping it's not the flap controller board, but I don't think that's it because the flaps seemed to work normally other than the pause mentioned above.

When I took the wings off for inspection and sight tube replacement about 6-8 weeks ago, I greased the flap mechanism and it seemed to be working freely.  I have had no trouble at all with the flaps system during the 590hr of operation, until this past flight.  It was unusually cold yesterday (for Georgia), about 26°F, but I'm not sure how that could be a cause of the problem.

Suggestions, ideas?

 

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Most likely from the cold. When the flaps stop like that and the display flashes, it is because the control boards senses that the current is to high. It is set that way to prevent damage to the motor or mechanism. You can also see this if you are to fast when trying to deploy the flaps. There is an adjustment on the flap board that could be tweaked a little to allow a little more current, but I would wait to see if the problem goes away when it warms back up.

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more likely when first cold.  more likely when charging / battery issues.   fixes itself first x,000 times I'm sure at some point its a concern.

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Thanks guys.  I won't worry too much unless it persists.  Until the cold goes away I'll just give the flaps plenty of time to cycle and delay deployment to lower speeds.

I will report back if it continues when it warms up.

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Anticept   

Also use a lower viscous grease. Something that has a high operating temp range while still being designed for jack screws and gears.

 

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36 minutes ago, Anticept said:

Also use a lower viscous grease. Something that has a high operating temp range while still being designed for jack screws and gears.

 

I use the Mobil 1 red synthetic grease, I think that is the same stuff Roger uses.  Being a synthetic it should have a pretty wide temp range.

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Runtoeat   

Andy, I think it's a combination of the cold combined with  possible battery condition/charge combined with Mobil 1 grease. My flaps would do the same as yours before I installed the diode which raised my voltage.  With better voltage, I no longer get the blinking display that was combined with stops and starts of my flaps.   I have found that Mobil 1 grease will set up to become a hard mass in my front strut if left for a few months.  I no longer use the Mobil 1 but use AeroShell #6 or # 7 grease based on my mechanic's recommendation.  For control surface bearings and flap mechanisim lubrication, I use the lubricant that Roger recommends which is Inox.  This stuff is not petroleum based but is lanolin based and is really good, especially for low temps.  My garage door screw drive opener stopped working during low temps last winter.  Low temp Lubriplate completely locked up the drive.  I used Inox to chase out the low temp Lubriplate and the drive now functions quietly and extremely well during below zero temps.  I have not tried using the AeroShell on my flap mechanism but even though this grease seems to be fluid, it might have too much viscosity for this during extreme low temps?

https://www.shell.com/business-customers/aviation/aeroshell/aeroshell-greases/about.html

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CT4ME   

Cold weax has definitely affected my flap operation, not that it gets cold here much.  But when it gets down below 40, my flaps definitely growl and move slower.  I'm guessing the extra air pressure needed to add more flaps, just makes it worse.

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Dick, thanks I will try your recommendations.

Tim, thanks for the confirmation.

I might not have sufficient lubrication, I will check that first and add Inox.

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Anticept   

http://aircraftspruce.com/catalog/eppages/exxongreaseshc-100.php?clickkey=72641

This became my general purpose grease. It's designed for wheel bearings but also is allowed for general purpose use, including jack screws and slides

I would not use it anywhere that super high pressure is required, such as places that call out for molybdenum grease. No place exists on most light aircraft.

I found it to perform far better than aeroshell 5 through 7. I do not know how it compares to 22 yet as I have not used it, but I do have a tube I wil be using soon.

I used it in the nose gear assembly and recieved far fewer complaints even as time went on.

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11 hours ago, Anticept said:

http://m.aircraftspruce.com/catalog/eppages/exxongreaseshc-100.php?clickkey=72641

This became my general purpose grease. It's designed for wheel bearings but also is allowed for general purpose use, including jack screws and slides

I would not use it anywhere that super high pressure is required, such as places that call out for molybdenum grease. No place exists on most light aircraft.

I found it to perform far better than aeroshell 5 through 7. I do not know how it compares to 22 yet as I have not used it, but I do have a tube I wil be using soon.

I used it in the nose gear assembly and recieved far fewer complaints even as time went on.

It should be good, for $82 for a can!!!

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