Hello; I have one of each size of the surpass series at least. The ones I use the most are the 4 26's I have. I used a 48 for years on a midwest Suhkoi, and a 70 on my seamaster. And the 91 on an ultimate and an estra 300. I've gone over to Saito too, and now use them exclusively, from 30 to 150. Power to weight ratio allows me to fly lighter planes, also the Saito s are quieter.