3gx wobble

[Rowey]

My trex 500 efl pro seems to have acquired a nasty wobble during fastforward flight (15mph head wind)
could anyone advise on possible settings that may require altering, I have had this heli a year but never had to adjust 3gx settings. mechanically everything seems to be ok
ta
jon

[adrianMS]

There's a few variables with the 3GX-Version & gain. I've had wobbles due to both of these reasons. "Porpoising" in FFF on the V2 software & elevator gain too high on the V4 (V3 was good except on take off & landing-very "tippy"
Are your batts still upto the job? poor head speed can cause problems on any heli with stiff head dampers.

[tourerjim]

My trex 500 efl pro seems to have acquired a nasty wobble during fastforward flight (15mph head wind)
could anyone advise on possible settings that may require altering, I have had this heli a year but never had to adjust 3gx settings. mechanically everything seems to be ok
ta
jon

I had same problem & new it had to be mechanical as I hadn't altered anything, turned out to be motor bearing pinion end.

[coolice]

Hey buddy.

As the model has been flying ok I'd look at things that can wear over time and change the behaviour, such as the head dampers getting worn and allowing the feathering spindle to move in flight. Are they the older rubber type or the newer POM harder material type.

As mentioned are your batteries loosing their edge, the head speeds is changing and causing the wobble.
.

[Rowey]

Thanks for the advice.
The only thing that has changed is that I have tightened the rotor head onto the main shaft as I had a little slop, it now fits very snug . Do you think this could cause the wobble?

[coolice]

Thanks for the advice.
The only thing that has changed is that I have tightened the rotor head onto the main shaft as I had a little slop, it now fits very snug . Do you think this could cause the wobble?

Evening Mate.

You're welcome, glad to offer some help.

Could be linked. You've not mentioned what firmware your 3GX is running, is it V2.1, V3 or the latest V4? Also where are your pots set to on the 3GX, what settings are you running and head speed?
.

[Rowey]

Evening Mate.

You're welcome, glad to offer some help.

Could be linked. You've not mentioned what firmware your 3GX is running, is it V2.1, V3 or the latest V4? Also where are your pots set to on the 3GX, what settings are you running and head speed?
.

Thanks again
the dampers are the stock black rubber type . 3gx pots are both just past center (60%?) and the firmware is 3.1, running
iu 1 80% iu2 90%

[adrianMS]

Try upping head speed to 100% iu2 & try again or borrow a new batt to compare against your packs. After that check gain pots. If still no joy its got to be mechanical. Start with new dampers & check blade grip bearings/thrust bearings while you've got the head apart. I've just done all of this on my 450 while hunting down a wobble on the cyclic, turned out the gain was too high (been flying indoors all winter no problem. 1st time outdoors-shaking like a sh*tting dog!)

[Rowey]

Try upping head speed to 100% iu2 & try again or borrow a new batt to compare against your packs. After that check gain pots. If still no joy its got to be mechanical. Start with new dampers & check blade grip bearings/thrust bearings while you've got the head apart. I've just done all of this on my 450 while hunting down a wobble on the cyclic, turned out the gain was too high (been flying indoors all winter no problem. 1st time outdoors-shaking like a sh*tting dog!)

Will change the dampers today and hopefully get out and give it a good fly round, I will also up the head speed , what kinda bothers me is that it has been fine so hopefully it's just the dampers

[Rowey]

The wobble is still there even with new dampers, it improves with increased head speed but is still evident. A couple of things I have noticed is the swash has a fair bit of slop and one of the servos is notchy

[adrianMS]

Every Align swash I've ever had has been pretty dam sloppy from day 1.
Any dodgy landings recently? Most mg servos need a good whack to go notchy. From past experience instead of being regular shape they tend to have a curved shape rather like a breaking wave.

[tourerjim]

500 servo's are known for bit of slope but not a notchy feel, the head speed is fine but i would double check the motor as im on my second set of bearings.

[Rowey]

500 servo's are known for bit of slope but not a notchy feel, the head speed is fine but i would double check the motor as im on my second set of bearings.

At the risk of sounding a bit thick but what is the best way to check the motor bearings?

[tourerjim]

At the risk of sounding a bit thick but what is the best way to check the motor bearings?

You will need to take the motor out hold the body then grip the pinion to check the side play of the pinion.