Hi,
I'm experiencing a problem with my Axe.
When I'm hovering, the heli tends to either drop or rise without throttle/collective input. Sometimes it's a slow change and sometimes it's sudden [X(]! Sometimes it's a little change (a couple inches) and sometimes it's almost 1.5' - 2'. Gets the heart pumping when it does that!
At first, I thought it was because of rotor wash. I was hovering inside in the basement. But happens outside in the yard and in the garage where there's plenty of room. I also thought it was my piloting skills, but I know I'm not moving that left stick. I can hover my HBFP almost motionless for minutes at a time. I can keep the Axe still left/right and front/back, it just changes altitude.
I read about stock servo slop and checked mine. Sure enough, there was some slop. So, I took out the stock servos and replaced them with HS-55's. Still I get the rise/drop thing going on.

Is is what is called a "sticky collective"?
What can I do to fix this (besides keep practicing!)?

Any help would be appreciated!

Also, I plan on getting a DX7. I want to get the AR6100 receiver correct? I would like to use it in the Axe and I eventually in a TRex when the time comes...

Thanks!
-Vince