That’s an awesome story. Do you have a photo?
The tractor is still at my parent's place, covered with junk. Unfortunately, I don't have a photo to upload right now... We both had an interest in flying so we made huge kites out of plastic sheeting and dimensional lumber to tow behind it. Our idea was to make something big enough to tow us aloft. Fortunately we were never very successful with that. But I did eventually buy a hang glider that we could tow behind a boat. My brother has been a captain at a major airline for decades. And I live on a small airport with my wife and wiener dog.
Thinking back I think that it was the kickback that made the crank so dangerous. I don't think we had the timing quite right when we first got it going and our technique wasn't the best. The thing wacked my brother on the forearm so hard that he had to get x-rays to make sure it wasn't broken.