I recently got the World Models Extra 30 Sport (the red one) and I put a Thunder Tiger GP 42 thinking that even a 40 sized sport engine would be overkill (which I prefer) for this 30 sized sport plane. I WAS WRONG! This engine has very nice running characteristics but not nearly the power I was hoping for. And this plane seems to be a little on the heavy sider for a 30. So I was hopeing for some suggestions. I would like to stay at or below 15oz, with the muffler, to keep from haveing to use a lot of lead to ballance. It seems that you either have to go with a light 32-40 enigne that is low on the power range. I can't seem to find anything with power in the 1.4hp range that isn't over 16oz's. Please give me some educated suggestions from your personal experience so I can find the right engine for this nice flying plane. By the way, I am hoping for something that will give this 4.5 to 5lb. plane unlimited vertilce. Thanks for any input, Eric.