mine hasn't flown yet, I tried once but I was running an 8x8 and was only getting about 14,000 rpm or 15,000 maybe. It wasn't enough at our altitude, didn't go well, kinda wallowed in the air and then hit the ground nose first. It broke the end of the enginemount off so I had to repair that. But, now I have a pipe and header on it, it's powered with a West50 VI so I should have about 19,000 rpm with the 8x8 next time, that should make a huge difference