Bill....thanks for the correction on Monoline. I can't even imagine trying to do a square using that system although I don't think they were even thought of back then

The advantage of a single blade prop is that you can have a large enough disc area to generate the thrust while keeping the load down on the engine so it can reach the revs needed for maximum HP. In that video he's definitely using 2 lines because Monoline is banned for FAI speed. In fact, they're not even allowed to use "groupers" which were used to keep both lines close together to reduce their drag. The fuel he'll be using is a simple 80/20 with all castor (that's why it's called FAI fuel ). The handle locks into a pylon so that the radius is constant and to prevent any whipping. Timing starts (I think) one lap after the handle is placed in the pylon because they have to whip like crazy at first to get the engine to unload enough to come on the pipe.