I bought the Keiv 3 blade from Ted at B&B in Md. and have it on my Rans S7. I like the prop a lot, smooth no vibrations like I had on the 2 blade Sensenich ground adjustable composite prop. I had a drumming effect on the wind screen at 5200 on my rotax 100hp. I think I will try the Whirlwind on my Kitfox SS7 also due to the situation with the blade replacement.