Its the full flying rudder. It moves around a bit, even with the best linkage and if you fly it too fast, its very noticeable.

The tips removed do make the plane roll and knife edge better.

If you want a more positive flying plane with equal or better 3D capiblity, look into the Hype 3D.

I luved the Flip until I got a Hype. The Hype just flys better, as you described, a pattern plane has a certain feel with very positive respones and most 3D planes don't. They do some hard core stuff, however don't fly very well.

Hype 3D