I think something that is going to be close to what you are asking is in the thread in the "At The Handle " section, about the guy that has a Vector that weighs over 60 ounces. At 500 and some odd square inches, I don't think you can put enough horse power in it to get it to fly a pattern. More horse power means a bigger engine which means more nose weight which means more tail weight to balance. I have built and flown heavy airplanes and got reasonable performance from them, but there is a limit. I think the obsession over trying to get an uber-light model, or the "zero ounce stunt model" is one side of the pendulum arc, and "too heavy" is the other side. Every wing and airfoil has it's optimum wing loading and speed for generating the best lift, The math wizards can give you a formula, I'm sure. I have had two models that were 72 ounces or more. One powered by a ST.51 (a SIG Magnum) and the other a Cardinal powered by a ST.60. I got my first 500 point score with the Magnum, and won my first expert level contest with it. The cardinal was just a test bed mule to learn how to run ST. 60's It was bigger and most likely had more drag. Just going by memory, I think the Magnum flew better hands down at that weight. It was a bit smaller, more aerodynamically clean, and just better proportioned. I don't think the ST.51 put out more power than the ST.60, the Magnum just used the power available better. But if the weight of that Magnum started to push 80 ounces, pulling up into that first wing over would be interesting!
Type at you later,
Dan McEntee