I have not put a tack on my DLE30cc but by my ear it sounds like at least 7800-8000 RPM I am running a 18x10-6 the same prop I had on my G38 Zenoah! It spools up faster tha the G38, but the G38 had a heavy flywheel that takes power to spin up fast. It is getting smoother after runnning cycle no 5. Not real smooth at 3000 RPM but at high RPM it smooths out again. Best not to run em at the rough RPM at all. The tilting deal should not be a issue. People should start up this size of airplane/engine combo on the ground, and not be moving or carrying them when running. I like the engine so far. The 4 bolt hub is a pain when drilling for use. Best regards Capt,n-