Tail drift with GY401 & 9257

[Russ]

I'm experiencing a slight anti clockwise tail drift with the Futaba Gy401 & 9257 installed in a Trex 500. Mechanically the setup looks good and runs smooth. I've also been through all the steps in the manual and upping the gain makes no difference.

I was wondering if this could be a vibration problem? Currently I have the gyro mounted on the small platform behind the main shaft and I'm going to try moving it further back of this tray, but first need to get hold of some new mounting pads.

Any recommendations for a specific type of mounting pad - are the standard futaba ones pretty good?

Russ

[Guy]

The standard pads are pretty good, that probably wont be the problem.

Have you tried setting the tail up with the gyro in rate mode. Move the tail blades round in the grips til the tips are almost touching and in rate they should line up.  If not adjust the srveo along the boom until they do.

Then try a hover in rate mode and adjust the gain (or the rudder endpoints depending on how its setup) to get it pretty solid, then set the heading hold mode to a similar value and tweak it from there.

[Russ]

Yep I've trimmed the tail in rate mode and reset the neutral position, but still the slight drift no matter what the gain in heading - hold.

I've considered temperature - I leave the heli to stand for 10 mins to reach ambient.
Gyro vibration - I'm going to try a double thickness of pad and move the gyro back.
Electrical noise - ? I know the Spartans use a sandwiched metal plate in the mounting pad.
Servo holding power - Currently at 4.8V using align step down. May remove the step down and set the BEC to 5.5V.

[Guy]

It doesnt always make sense but crash-alots stock answer to most gyro niggles is re-binding, rather annoyingly he's usually right.

Try a thicker pad, that wont hurt, and moving it away from the main shaft might well help, but I've never heard of anyone suffering issues with elecrical noise before on this setup and its a very common combination.

I wouldnt have thought its going to be the servo power, once its in a hover there's not a lot of torque going through the heli so it doesnt require a great deal to hold it, usually if thats the case you will lose the tail on fast climbouts but it will still hold once you level out.

[Russ]

Thanks Guy. I'll try re-binding when I move the gyro.

Will let you know how I get on.