Ok this may sound insane but I was wondering if you could run a tiny prop on a nitro car engine? Just daydreaming about mounting one on a stryker instead of using electric . Those .21 size engines run screaming high rpm so why not run say a 6-4 apc and see what happens? I realize those engines have no bottom end power but if the prop is small enough wouldn't it work?

Sounds like a good way to get hurt. Putting a 6 x 4 prop on a 21 does not sound like a good idea to me. Just my thoughts, Dave

The cranks on them, for the most part are to short to mount a prop. They are setup to mount a clutch.

I had an old O.S. SE .21 car motor with a full sized crank on a plane. I had to take most of the heat sink off. I ran it with a 8.5X6 prop and it ran right at 21,000 RPM with 30% fuel and tuned pipe. It was a good combo with the Aritronics Jetfire 20.

Running a 6 inch prop would not be a good idea. It would go way beyond the limits of the prop. You could easily shatter the prop and stuff lying every where.

Dru.

Maybe an old Cox glow engine or a little Norvel would be cool but not the bigger car engine.

well maybe a carbon pylon prop would work..