RE: 150MPH 4 cycle airplane/engine combo?
You may want to talk with the "other" rcguy and see how he does it. He seems to be going a 1000mph in a 65 inch Voodoo. But Razor is right. There are manywho fly that WM 40 Size P-5 or Dago with a YS110. I have a saito 100 in mine. Its about a 110mph plane. If you can get a 4 stroke combination to go that fast, it might be a one flight deal. After landing the engine may sound like a coin change machine