well, Fly, I really never have owned an OS engine unless my Graupner/OS/Wankel .30 is made by OS. And that story about the Cessna, seems like the fault was in chosing too small engines rather than the brands fault. Fox. .74s are strong for their size. I don't have any OS engines because no other brand has given me cause to buy an OS. The Fox .15 I mentioned above is my 97th engine. I recently found a HB 120 twin I had forgotten about.