I already have an Irvine 39H (new) for my Rap 30 (under construction). The guy in the Model shop swears by his.

However, I have always used OS and know them well.

I thought I'd get the Irvine 39 as opposed to the O.S. 32 for that extra little bit of power when I want it, but I'm hoping the engine will run well and be reliable.

Have I made the right decision? Any comments on Irvine engines? Should I take it back and exchange for the O.S. before I run it?

By the way, when he showed me both engines in the shop, I noticed that neither of them were ringed - does this matter in a Heli? You may have got the feeling by now that I have returned here after a long break from the hobby, and there's a few things I've forgotten

Luke