I have a TREX450 with a Spectrum DX7 transmitter and Spectrum AR7000 receiver.

Servo's are digital are Robbe FS61BB, and Align GP780 gyro.As a traditional heli without APM it flies fine with smooth servo movements and stable tail.

The APM has been set up as advised on the website. I have replaced the flybar propellor with a flybar-less version and have disconnected the gyro.

Connecting the APM to Mission Planner, programming the APM,arming the unit etc works fine and also the adjustments of all the stick movements in radio calibration are as required. Movement of the heli results in the correct response from the servo's and in Mission Planner the movement of all three axes are as they should be.

I have the following two problems:

- the servo response to movement of the stick on the transmitter for rudder, pitch and elevation is normal and equally smooth as without the APM, but the response to the roll is very nervous, fast and with large movement

- when I try to start flying the rudder is not keeping the heli in position and once the propellor gains speed the heli will rotate around it's axis.

Can anyone advise me wat to do.

Huib