Thanks for the reply,
I am not sure of the weight of the aircraft, that will be checked, but I was trying to take it off from a paved area. I only have one of the cox .049 black widow engines installed with an old r/c receiver and standard sized servos. The model kit is a Guillows Fokker Tri-wing 1/16 scale with a 20" wing span. It is supposed to be control line capable but I added all the r/c stuff inside and the model doesn't want to fly. Could changing the pitch of the engine assist? The control line directions had me pitching the engine downward by about 2 degrees with shims. If it needs to parallel with the cord of the aircraft I can do that simple enough. What type and size r/c receiver and servo do you use in your 1/2a models?