Which tail servo for gasser?

[boomstriker]

Hi, I have recently bought a second hand P Gasser. I have fitted it with the GY401 and 9254 servo combo, but I can't seem to get the tail to hold in the hover, it wants to swing either way when I increase or decrease power/pitch. I'm well versed to using and setting up this combo on nitro machines, but with this machine I just feel that the tails going to let go at any time and I don't feel confident with it. I have read that the 9254 may not have enough torque to cope with the power from the Z231engine, so which tail servo do most pilots use on this machine? It initially came with a CSM 420 and JR8700 but their seemed to be a lot of fore and aft play in the JR servo, which I thought was causing the tail to drift, so I decided to change it for the futaba gear. Any ideas on this would be much appreciated.

Cheers, Kev........

[RAV50]

Assuming that all is well with the gyro and the servo, such a drift is usually caused by the gyro sensing vibrations and reacting to it. This is far more prevalent in the higher vibration environment of the gasser.

a) Make sure the gyro is mounted in a manner that will best isolate it from any vibration. Use proper gyro tape. Apply one layer to the bottom of the gyro, then a plate of something (e.g. an aluminum square the size of the bottom of the gyro like that supplied with the GY-611), then another layer of the gyro tape which will be attached to the radio tray.

b) be sure the engine/ fan / clutch is dial indicated for the minimum run-out and that is aligned properly to the clutch bell. This will insure minimal high frequency vibrations that can result from run-out and misalignment.

c) make sure the needles are set for smooth operation - the low end needle is for hover and the high end needle for full power.

[jackheli]

I had the same exact issue with the 401 on my gasser. It got so bad the tail would go on a violent large swing wag.

I replaced the gyro with a CSM 560 and the issue went away.

I would suggest that you mount the the gyro to a plate with medium double-sided tape, and then mount the plate to the heli with thick tape. Make the plate preferably from a heavy metal.

Just as an inside, the set screws inside the tail box ended up failing shortly after, maybe because of the gyro's tail abuse. I would suggest you double check that all screws are secured and locked inside the tail case.

[DebianDog]

... and get the motor running smooth as possible