Ski, your TS .52 sounds like a real screamer. Are those prop sizes a little small for this engine? I used to fly a TT .36 Pro on an 11x4 Zinger, which it turned very well on my .40 size fun fly. Don't you have noise issues where you fly? (Prop tip speed being a major factor.) I'm not questioning the engine, which is favorably reviewed here on RCU in conjunction with the Kangke 50 something or other.