The best e-lectric props I have found for sport flying are the APC they do make 20+ inch props check them out Most of my e-flight so far has been park foamies And I am know venturing ito a 4o0 size convertion The same zize e-prop compared to glow gives a lot more pull and increased rpms in september 2005 Model airplane News did a 1/4 scale Pitts bipe convertion they used APC prop Hope this Helps some