Centering problem
05-20-2009, 03:33 PM
#1
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Centering problem
I've been instructing at our field with the club trainer. One day the elevator will be trimmed fine, the next day elevator will be down about half its throw. I recentered it with the clevis at the elevator and flew. The next day the elevator was up about half its throw, retrimmed it at the clevis and worked fine.
I'm hoping someone has run into this before, could it be the servo with a false center, reciever or Tx?
Nobody else has flown the plane but me, it has a futaba 127DF reciever, hi-tech standard servo's and a futaba non computerized Tx. Otherwise the plane has been truoble free, so far I've noticed it out of trim on the bench during set up, has'nt happened in the air.
Thanks
I'm hoping someone has run into this before, could it be the servo with a false center, reciever or Tx?
Nobody else has flown the plane but me, it has a futaba 127DF reciever, hi-tech standard servo's and a futaba non computerized Tx. Otherwise the plane has been truoble free, so far I've noticed it out of trim on the bench during set up, has'nt happened in the air.
Thanks
05-20-2009, 04:11 PM
#3
My Feedback: (61)
RE: Centering problem
what type of pushrods?
have you tried another servo?
I would try - 1st, double check integrity of pushrods - look for slop, slipping threads on clevis / pushrod, etc.
2nd - new servo. Pots in servos get dirty with age, can cause bad centering, etc.
3rd. If pushrods are ok, and servos are ok, I'd suspect stick pots in transmitter.
Might also look at connections in radio setup in plane, make sure all servo connectors are tight, clean, and fully seated.
have you tried another servo?
I would try - 1st, double check integrity of pushrods - look for slop, slipping threads on clevis / pushrod, etc.
2nd - new servo. Pots in servos get dirty with age, can cause bad centering, etc.
3rd. If pushrods are ok, and servos are ok, I'd suspect stick pots in transmitter.
Might also look at connections in radio setup in plane, make sure all servo connectors are tight, clean, and fully seated.
05-20-2009, 04:22 PM
#4
Senior Member
RE: Centering problem
Check the arms on the servo. If you accidentaly put a different brand of servo arms on the servos, they could be slipping. Make sure that the arms are also tightened down properly. sounds like they are slipping under stress.
05-20-2009, 05:23 PM
#5
RE: Centering problem
mvallyman:
You need to isolate the problem first, since it could be anything.
I would start disconnecting the servo and verifying the movement of the arm under load (oppose it with your hand); it should be symmetrical and always the same amount (measure it).
Also move the wires between the Rx and the servo while testing it.
I would continue with the rest of the linkages, if the servo is proved innocent.
If that is not, then connect the servo to a different post of the Rx and re-test.
Hope you can solve the mystery.
You need to isolate the problem first, since it could be anything.
I would start disconnecting the servo and verifying the movement of the arm under load (oppose it with your hand); it should be symmetrical and always the same amount (measure it).
Also move the wires between the Rx and the servo while testing it.
I would continue with the rest of the linkages, if the servo is proved innocent.
If that is not, then connect the servo to a different post of the Rx and re-test.
Hope you can solve the mystery.
