George, thanks for the reply and as to what are we flying now? Latest is a barndoor from Ray Stone with a big mig 061 ( this is a great model and thanks to Ray for helping me learn to fuel balloons!), plastic fantastic w/ ame 049 (fuel from muffler pressure with the larger norvel clunk tank and homemade mount), osborne platter w/ black widow, deweybird w/black widow, and a collection of balsa, corfoam, and coreplastic "flying wings" that i play around designing with tee dees, medallions, babe bees and golden bees. Yesterday we flew an 18 inch plastic core wing with a kb greenhead 09 and my little 14 year old flyin buddy had his hands full! My biggest problem with the plastic and foam core airplanes is always fuel foaming from vibration, seems the high power engines (ame) and anything larger than an 061 won't run good on balloon or regular tanks and bladders might be a little much for us right now. Also guessing at the balance point, most of the time they are a little tailheavy so i make brass prop nuts to counter. Our goal is to practice with these practically indestructable plastic wings to be able to fly inverted by July 4th so we can fly the "good models" to show off at a family get together. This is a great website and thanks for any thoughts. Ray