90SP knocking
I have a question from my flying mentor. Today at the field he was making a flight with his Corsair which has a 90SP in it, after several minutes of flight his engine dead sticked and he managed to get the plane down fine. Later when he went to fly it again it had a loud knock at idle. When the motor reved up the knock went away. He did not fly fearing he did some internal damage to the engine. The day was cool so I don't think the motor over heated on the first flight. Any thoughts?