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
Replies
Roll rate can be adjusted in mission planner, try a very low number like 1500 (degrees times 100). that should calm it down a bit, and remember the APM will increase the signal to the servo until it reaches the desired angle as defined by your stick input, so set the maximum servo travels in mission planner accordingly.
For the tail, it sounds like the gyro function is in reverse, I.e. if you disconnect the ESC and power up the heli on the table in front of you, arm the APM, then with the heli tail-in rotate it counterclockwise rapidly. The tail blades should angle to thrust in a clockwise direction (counter to your movement). I suspect you will find the blades will want to thrust counterclockwise... You'll need to change the rotor servo direction in mission planner (which will make your inputs incorrect at the radio), then reverse the radio to correct stick-to-tail relationship.
Remember, servo direction is set so that the swash leveling / yaw control is in the correct direction first, then you reverse your transmitter as necessary for proper stick relationship.
Check that when you tilt the copter fore and aft the swash plate tries to remain level, I.e. when you nose down the copter the swash plate raises in the front and lowers in the rear. Same thing for left and right roll.