ORIGINAL: 2slow2matter
If you have a high pitch prop, that could likely be your problem.
also, you could mix in some spoilerons if you want (upward deflection). This acts to kill the lift. It won't really slow the model much, but it will definitely force it to the ground. I wouldn't recommend it, though. Plus, spoilerons are never a good idea because you are (in effect) going to force (or at least influence) the outboard part of the wing to stall first.
As slight amount of spoileron actually works like wash-out and
prevents a tip stall in barn door ailerons. Not in full-length ailerons, though. That's wht the outboard ailerons flip up with the C.R.O.W. and Butterfly settings in gliders and uber-aerobic models.
http://www.fly-imaa.org/imaa/hfartic...t/v1-4-10.html