That is a weird looking prop. I guess it works, but why would you want one?
According to the info I picked up that day, the '37 Cubs (and many other lighter single pilot sport aircraft of that era) were powered by the 40HP Continental engine. Many two-place Cub pilots were wishing for shorter takeoff rolls and a better rate of climb. This "Everel Propeller" was the answer. The claim was a 25% increase in top speed, 30% increase in rate of climb and a 50% reduction in takeoff roll. The folks in Lock Haven did a side-by-side demonstration with a normally propellered J-2. The one-bladed version did appear to perform better in all areas mentioned. Made me a believer.