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Roll Trim Problems

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Roll Trim Problems

Old 07-29-2003, 02:46 PM
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crotts
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Default Roll Trim Problems

Sorry if this might not be the proper board for this question, but I'm at my wits end (which isn't very far), so I thought I'd turn to you guys for some advice. here's the deal:

I'm flying a Dragon Lady 40 which I just finished about two months ago. It has dual aileron servos mounted in the wing. After the first couple of shake-out flights, the plane flew great. The trims never needed adjustment and it track straight and true.

Then, one day, it wants to roll right in a bad way. I moved the trims left (almost all the way) and it seemed to correct OK, but after a couple more laps, it rolling left like crazy. After trying to chase the trims back and forth and almost crashing in the process, I got it down in one piece.

I had a much more experienced builder and flyer take a look. He thought it might be some slop in the aileron linkage due to my poor z-bends. So, back to the shop. Got all that taken care of with clevices on both ends and made sure the hinges were all good. Double-checked the rudder linkage and hinges too.

Back to the field and it's still doing the exact same thing.

The only other thing I can see that's different, is that my battery was a bit loose and was able to shift a half inch or so. I have resecured that but haven't had a chance to test that.

So, my question (finally) is: is that much movement in the battery likely to cause such results? And if not, does anyone have any other ideas?

Thanks in advance for your help.

Neal
Old 07-30-2003, 12:17 AM
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Parkerm
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Default Roll Trim Problems

I would suspect a servo that won't hold center to start with.
Old 07-30-2003, 12:21 AM
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Ed_Moorman
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Default Roll Trim

It could be something else in your radio, but it sounds like it could be one of your aileron servos has poor centering. It may just be a low end servo has started drifting or the pot has gone bad.

I test fly a lot of planes and poor centering servos are common. Some servos are more prone to this than others. Disconnect the aileron and tape a 6 inch long balsa stick to the servo arm. Tape a piece of paper to the wing under the servo. Move the aileron stick one way, release and mark where the end of the stick centers. Do this the other way and compare the 2 marks. If they are off much, replace the servo or put it on throttle. Check all your servos and it is best to put your most accurate servos on ailerons.
Old 07-30-2003, 09:32 AM
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crotts
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Default Roll Trim Problems

Great advice. Thanks. I'll try it.

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