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Concerning the methanol/nitro burning engines your statement, "Compare that to the glow engine guys and the alky burner boys have basically one mfg of 3 blade props and that company advises matchups from the 70s ....", is not altogether accurate; APC along with M.A.S. provide offerings and the recommended mathups are tried and true. The 2-blade to 3-blade conversion as previously stated does work but as noted is a starting point from which to experiment from if so inclined. Speaking for myself, the cool factor and mystery behind running more than a standard 2-blade is the lure. Also, given the availablity of small 3-blade spinners allows increased safety to those with an elec starter[8D].