Saw something like this happen a few years ago. Guy was flying a Stearman, suddenly calls "no control".

Plane starts circling downwind, couple more guys take of in a car in pursuit, and manage to track it until it runs out of fuel.

Plane comes down in a field (good) but manages to find the only tree in it (bad). Damage was as I recall minimal though.

The cause - a faulty battery switch which, I believe, is a strong contender for culprit in your case.

Terry