If your LT-40 really weighs over 7 pounds, you are going to find out two things really quickly: 1) the front nose gear will bend at the first bad landing. 2) the rear gear will spread out (and stay that way) at the first bad landing. I love the LT-40 powered by an OS FP .40 - had plenty of power for training. Built one years ago, but Sig landing gear is notorious for bending as the metal is soft. If you teach takeoffs last, you could get away with conventional gear and less weight (just a thought).