No YAW output at certain collective pitch Heliquad

ArduCopter Copter 3.6
1

Hello.
I’m building a heliquad and I’m using a Pixhawk cube with the latest ArduCopter software. I’m facing quite a weird problem with the YAW. The heliquads pitch mechanism differs slighly from one another and thus I’ve had to separately set the max/min/trim differently on all servos.

So. I’ve done a sort of maiden flight which went fairly well. The pitch/roll/collective pitch all seem to work well. The problem is that, at “hover” collective pitch the YAW hardly gives any output. The servos hardly move at all around the point where the heliquad is hovering. I’m having a built in slow left-yaw movement which I cannot parry and the autopilot cant correct it because it gives no YAW output at hover.

However, they do move quite a bit if I pull up the collective pitch to 100 % as well as below 40 % collective pitch.

Could my max/min/trim have something to do with this?

Any help would be greatly appreciated

2

This happens in my heliquads as well, but it doesnt affect flight. Are you having an issue with flight or is this a pre-flight, bench test? I see from a few other posts from you that you seem to be building a huge beast. I would love to see and I totally would understand if you are bench testing the bird beforehand and seeing this YAW output issue at mid-stick. My yaw output is just about null at knife’s edge but before and after zero pitch, its fine, but, mind you, it flies perfectly well so I believe this is by design. I would suggest getting familiar with the full parameters list and what they do, especially the collective pitch params.