Trex 450 trying to roll on take off in stabilise

ArduCopter Traditional Helicopter
1

Hi guys

Im having issues trying to get my trex 450 off the ground. as soon as I give it just enough pitch to come off the skids it wants to roll hard to the right or if I try to counteract it it will just roll hard left. as i have a large trainer on the bottom of it (the only thing that has stopped it being destroyed) it keeps contact with the ground until the heli is up to 45+ degrees from level (which happens straight away) at which point i put it down as quickly as i can. it doesnt seem to be oscillating more just wants to roll in 1 direction quickly. The blades are ballanced and i have checked the head is setup properly so @ 0 pitch i am getting 0 pitch all the way around. all the servos are going in the correct direction and collective is the correct direction as well. Prior to having the APM i was using a microbeast FBL unit and it was working fine then.

i have gone through the setup and looked at others settings and mine seem to be what others are using so im not sure what is causing this. I checked my vibration and it was ± 10 but i have installed a vibration isolation mount for the APM and now on the ground the vibration is around ± 2.4 but it didn’t make any difference to the rolling issue. i am running the APM 2.6 with 3.1.5 firmware

any input you guys have on this issue would be greatly appreciated

Ash

[attachment=4]heli setup page.jpg[/attachment]
[attachment=3]tuning screen.jpg[/attachment]
[attachment=2]on ground vibration.jpg[/attachment]
[attachment=1]flight vibration graph.jpg[/attachment]
[attachment=0]trex 450.rar[/attachment]

2

Can you send the data logs?

Does the swash move in the correct direction with both stick input, and when you move the frame? If you push left stick, the swash should move left. But if you roll the body left, the swash should move right to counteract the roll.

The vibrations are very high. This could cause the problem, but it’s not normally as severe as you’re describing. One problem is that the training gear can actually make the vibrations much much worse. Can you see them actually shaking when you lift up?

3

Hi Rob

I checked the swashplate and correct movement from stick inputs but opposite when i roll the heli :blush: . i swapped the servo positions in the heli setup page and it fixed the problem. now it hovers for about a second and quickly gets oscillations on the roll axis. would you be able to have a quick look at my tuning values to see if they are where they should be? (they seemed to be close to what others were using). for the time i did get it to hover the vibrations were better - X axis = ± 1 Y axis = ± 2.2. the trainer doesnt seem to be vibrating badly from what i can see but im sure its not helping but from what i have read it should be able to fly in stabilize mode with these vib values.

[attachment=0]2014-06-12 09-58-44.log[/attachment]

4

I have updated my tuning values and it flies good now in stabilize. i will work on my vibration levels to try to get them under ± 2 before trying alt hold and loiter. thanks for your help Rob

[attachment=1]updated tuning screen.jpg[/attachment]

[attachment=0]flight vibration 2.jpg[/attachment]