I have a Phoenix 46 Sukhoi (55" wingspan ~ about 6-7 lbs). I currently have an OS-46FX on it, but am unhappy with the power. The thing is a slug. Great engine, just want more verticle, more power...and have been thinking about buying the ST-75 to get it. It's about 10oz heavier than the OS. the OS has 1.62 at 16000 and the ST-75 has 2.18 at 15600 and the ST-61 ABC has 1.85 at 16500 rpm and weights about the same as the 75. Curious of your responses to this engine/plane match up. Is the ST-75 just too much? Will the ST-61 give me what I want? Opinions please.