Freya Tail problem when increasing RPM

[mf_read]

Happy New Year!

I have a Freya with a OS70 installed and recently fried my engine which I have had to replace. I have had the fan balanced which was OK.

The problem I get is when I raise the collectve/RPM the helicopter tail wags. Also when I doing downwind turns the tail wags during the turns. This happens in heading hold and normal mode. I have reduced the gains in the gyro and this appears to make no difference.

I have not crashed the helicopter, but have done no "preventitive maintenance" as such.

The electronics I am using are G7000T Gyro with 8700g Tail servo.

Jr 649s RX with DS 8511 on Collective and DS8301 everywhere else.

My gyro sensing is set to AUTO with the settings 75% 60% and 50% set.

The ATV on the gear channel +10 and -50 for tail lock mode. this appears to be the default starting point. I am using a JR PCM 9x TX.


I am not sure what to start changing, the helicopter has not always behaved like this, Is it possible for the Gyro to be faulty or is this a mechanical fault/issue.


Any help would be appreciated.

Mike.

[rob_jones]

After setting up a G500T/8700G in a Sceadu 50, I learned that it was very sensitive to gain settings. 1% too high and it would wag like crazy. Perhaps the new/rebuilt engine is putting out more power than the old and turning the head and tail faster? That would have the effect of increasing the gyro gain.

I suggest lowering the gain by about 20% and raise it 5% at a time until the wag comes back. Then back off 1% at a time until it's gone. It's time consuming, I know. But that's the only way I know of to fix it.

[mf_read]

Thanks for the post, I'm pretty sure I have reduced the gain considerably before with no apparent difference noticed. I will check again.

Also I have downloaded a different manual from the JR/MacGregor website for the 7000t which describes setting it up slightly differently than the printed instructions I got with it!

Thanks for your advice, I will try it when the weather is a little warmer here! and post back with any resolution.

Mike.