way more popular. I've never seen SS props for RC. (never looked for them). Actually what is the alloy most common? I think Octura is around: Cu (90%) Berillium (7%) and Titanium (like 3%). These are pleanty strong and are likely lighter than SS. I've had the pleasure of running an aluminum prop. 3 hrs of prep and it was on the boat for 6 seconds. Hit some floating mulch and it bent like a pinwheel. [&o]. Just remember that if your working with the CuBeTi alloy wear a mask if you are producing dust as it is a Cancer source.