I have this plane and could use some help with it.  It has an O.S. 91 two stroke in it, which should pull it around great, but the vertical is disappointing.  It slows down very quickly on the 15x4 and 14x6 props I've tried, and always falls off to the left, regardless of rudder position.  The elevator has shown some interesting problems as well ... full elevator at recommended throws makes the right wing dip severly.  Only way I've found to correct the problem has been to reduce the elevator throws, but now, of course, there is no authority in the elevator ... surely not enough to try a hover, but the rudder isn't that great for something like that either.  Definitely NOT a 3D plane.  Anyway, I'd love some advice on getting rid of the wing dip to get some authority back into the elevator, if anyone has some ideas about that.  Also, thinking that a .91fx should give me unlimited vertical, I'm curious what is wrong there .... wrong prop selection?  This plane should not be too heavy ... it's a .75 size!   One thing ... I have noticed that there is a slight warp of the left wing at the tip, as measure with an incidence meter, of about 2 degrees.  The wing starts fine at the fuse, and the further you get towards the wing tip, the worse it gets.  I'm going to try to take that out with some covering magic, but I seriously doubt that is the cause of my problems.  Of that, I can let you know when I try it.