need help with GY611 issue :(

[newbie]

Hi freaks :)

i need your help one more time.

My GY611/251 is drifting in AVCS mode only in a hover(slowly counter clockwise) on a JR AS 90.
No drifting at all in RATE mode in a hover ?!

One month ago no problem,the tail was rock solid in each mode,i perfectly adjusted everything as per the manual,only my limits are not equal(133/143) but heli was great in all flight mode.
I did the same on my friend's trex ,same gyro,and everything's ok so what's wrong with this gyro now ?

Is anybody can help me please?

thanks

regards

[BarracudaHockey]

Limits are pretty high, I'd first go out one hole on the servo arm and lower the limits before you fool with anything else.

Also make sure the sensor mounting is correct, that the wire doesn't have tension on it, and that you dont have a strap thats tight and transmitting frame vibration to the sensor.

[Wyn]

To check whether it's vibration related; Put the gyro in AVCS mode with the engine off, then use the rudder stick to get the pitch slider approximately centered when you let go of the stick. Don't move the heli and watch the pitch slider and servo. If they don't move for a minute or so, it's likely a vibration related problem. If it starts to drift on it's own, then the sensor has problems.

Most of the time, it's vibes. As Baracuda mentioned, wiring and attachements can cause problems, as well as engine bearings, etc.

[newbie]

Hi ,

Houston we have a problem :(
so i checked my pitch slider and i discovered something very strange !!
stick full down pitch slider ok don't move by it's own :)
Mid stick pitch slider is moving rapidly letf and right then stop moving and again and move completely anti clockwise,that's why heli drift in a hover.
full stick no problem at all :)

i have an electrical issue ok,but what's going on? one month ago everything was ok and now it's a nightmare !!

my set-up is:
3x 9452
1x 9254
Align reg/lipo
2x volt step down
GY611/251
319 dp rx 72Mhz

thanks guys for help

regards
lionel

[Wyn]

Check the TX programming -- I'd bet the farm there is an errant mix enabled. ;) You didn't say what model TX, but look at all the mixes, especially the built in mixes like "revo". If you're using a radio that can have mixes enabled in different flight conditions, check all the conditions.

[newbie]

Hi, Wyn
thanks for the help :)
so,my Tx is the Futaba FF9S but all the built in mixes that i know are in "INH" position or "NULL"
Is there some hidden ones? no revo mix for sure.
Any advise

thanks
regards

lionel

[Wyn]

No experience with the FF9, but some type of throttle to rudder (T/R), or pitch to rudder (P/R) is most likely.

[BarracudaHockey]

REVO is inhibited by default on the 9c Super (FF9S)

Here's a simple test. Move the throttle stick up and back making sure to use just one finger and not move the rudder axis. If the tail blades change pitch you have a mix enabled.

[newbie]

Hi,

ok checked everything again this afternoon.
-limit set 100/110 90° everywhere
-no mixes at all
-zeal tape/metal plate/futaba gyro tape under sensor
-wiring and attachment are ok (wiring are all in good shape,wire doesn't have tension on it)
-Rx inside quick uk crash box(box stuck on servo tray with zeal tape)
-Amp inside foam for test on the crash box

so,pitch slider doesn't move on it own now,but there is always a rapid movement both side(few °) of the tail blades when i reach the middle stick position only ?!(high and low position are ok)
It's more like a Rf noise(can't really explain it with my bad english :( the tail only move fast both side rapidly,maybe my tx have a problem(contact cleaner may help) or my Rx or Rx's plugs or rudder servo etc...
i'm gonna try another Rx(149DP) un plug all the servo except the rudder one i'll see what happen,and Saturday i'm gonna try another Tx with my friend it's gonna be a "trail and error day".

thanks again for help Sir

regards
lionel

[Wyn]

What you are describing sounds like something is wrong with the left gimbal.

Here's a couple "process of elimination" tests:

1) Move the tail control, from the left stick to the right stick by changing the leads at the RX. Pick a fresh default radio program (without any mixes) and set the gyro gain channel same as before, but plug the rudder lead into the aileron channel. Now use the right stick (instead of the left) with the same test as before. If the problem is gone, double check by plugging the rudder signal back into the usual channel and see if the problem returns back to the left stick.

2) Eliminate the gyro and servo. Plug some other servo (a spare would be ideal) into the rudder channel on the RX. Now move the collective/throttle and rudder, then see what happens.

[newbie]

YYYYYYYYYYEEEEEEEEESSSSSSSSSSS !!!!!! :)

problem solved today,left gimbal is the problem !!
gonna check inside the radio if i can see something?!

i'm happy it's not my brand new GY 611 or servos and so on ;)

thanks a lot Wyn and all the freaks on the forum ;)

regards

lionel