I am still using the original prop that came in the box. I haven't yet tried them, but I did obtain several of the Cox recommended APC props to use in the event the original didn't work out. I bought them as a result of the hysteria created by a couple of early users of the plane who had nothing but complaints about its capabilities and lack of power. It was later discovered that they had assembled the kit, fueled it up and flew it (and in attempting maneuvering flight, crashed it) without even running the engine for the slightest break in period prior to flight, contrary to the Cox instructions.

What engine does any of us own that does not require at least a nominal break in period prior to testing its full capabilities? I have yet to own any, if they exist!