RE: Anyone using one bladed props?
You can generally go up in 'relative' diameter to make up for the missing blade area from the other side, but it's an undertaking of machining to do it right and it's a bit of liability to make sure you don't fling something. I've made my own in the smaller 5" range of props and it was a bit of tinkering and a lot of balancing to get it to run well. Supercool's are pretty cool in that the blade 'keys' into the counterbalance so it can't shift. It's also mass balanced pretty well. I have no machining talents so I do it the cave-man way and just make it work.
The real advantage of a single blade, at least on smaller props, is that you can increase the chord length of the prop thus increasing the reynolds numbers and in the end increasing efficiency of the blade. The small props operate in pretty low reynolds numbers unless you spin the heck out of them. Increasing the chord length on a 2-blade will do the same but the load on the motor goes way up. So, transferring the surface area to one blade and then making it balanced makes it one efficient blade instead of two so-so blades (technical term). There are other theories on vortices and prop wash but I think it's the chord length that gives you the boost in efficiency.
Originally I made mine from my standard 2-blader with a blade cut off but it didn't make any real gains. In fact, it had worse acceleration. That's when I realized I needed to go to a bigger prop and then trim down diameter to increase the area. It worked OK but I never really did enough scientific testing or pylon raced it against the clock.
I don't know if I'd recommend it on a Jett .50 unless you are certain you know what you're doing. If anything flies off in testing or in the air it could be disastrous.