Motorized unicycle from the 50s (video)

My dad pointed me to this video, thought it was really neat. It’s drag racing footage from the 50s, and at about the 3:45 mark there is a guy standing on what appears to be a gas-powered unicycle maneuvering through obstacles.

Has anyone seen one of these before? I feel like more information is needed!

could this work?

Seems to me that one would need a gyroscope and some sort of (primitive?) computer to keep him upright. What’s the trick?

maybe he’s so high up because there IS a big huge gyroscope under him : P maybe a few of them xP