I just put together a new H9 Twist. It flies great with the 46AX and 12.25x3.75.
The problem I have, is it has a vibration hum between 1/2 and 3/4 throttle.
How do I find where this is coming from?
I tried to find it on the ground, but it doesn't seem to do it when being held???

I love the way it flies, but the noise sounds really bad. I had one spectator ask me what the noise was[X(]

any ideas????

thanks