Gregory's Server
I knew it wasn't a Mustang, totally different sound. Seems it was a T-34 Mentor, a WWII Beechcraft trainer. I've seen most of the historic stuff, I think, and I'd never heard of one, but I guess they favored the Navy. It looks like a mini T-6 Texan. It was his private aircraft.
Early '40's construction. I'd put an initial guess at a cable control or elevator problem.