Have you checked your gyro settings

try to adjust the gyro gain - either up, if its getting worse bring it down ...

I'd wind the gain up until the wagging was violent - twanging like an arrow - and then slowly reduce the gain 0.5% at a time until it stopped. The sweet spot!

This can be tedious - but it works

If it doesn't you have set-up issues, a moody gyro or servo, or unseen vibes.

have just noticed tail sevo making bit of noise so will change that and then adjust gyro from there , thanks everyone

Hey.

What tail servo and gyro are you using?
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You have to set it up mechanically before tweaking electronic. Make sure all servo arms are at 90° and that your tail rotor blades are vertical, then adjust the tail servo limits in your gyro. It should then keep your bird on a rail.

using savox 0257 servo and futaba gy401 gyro

Hey.

From memory the Futaba GY401 was one of those gyros which preferred to be csetup in rate mode first, before switching into heading hold mode.
You need to setup the tail with some tail pitch to counteract the torque of the main rotors, this is normally set by adjusting the tail pitch control rod so that the tail bell crank arm with the steel control ball is parallel to the tail output shaft. This should set just enough tail pitch to hold position, but will probably need adjusting out on the field, by flying the model in rate mode and adjusting the tail control rod length to make any trim changes. Do not use transmitter trims.
Turn on the model as normal in heading hold mode, then flick into rate mode and fly, be aware the tail may be out of trim and want to rotate/yaw slightly.
Now adjust the length of the tail control rod to maintain a reasonable hands off hover without the tail moving on its own accord.
Once done, toggle the gain switch 3 times and end with it in heading hold mode, as I'm pretty sure the GY401 as needs to have its neutral position re-learnt into its memory after the above setup.
With this done recheck your full tail travel limits and adjust the travel limit pot on the top face of the gyro so that there is no over driving/binding of the servo. If you have the lower this travel pot below 80%, you will need to fit a shorter servo arm on the servo. If on the otherhand you have to increase the travel pot to over 120% travel, then increase the arm length.

With gyro gain, if there is any wagging the gain is set too high, drop the gain within the transmitter ATV menu for gyro gain by 5% and try again, keep adjusting until there is no wag. If you start off with no wag, increase gain until you see it, then back off 5%.
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thanks alot for great advice coolice

You're very welcome buddy, glad to help.

Keep us posted on how you get on once you've made some changes.
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