Hi there,

I am happy with my OS FS70 Surpass II, which delivers 10,000 to 10,500 RPM on 15% nitro (Wildcat) on an APC 13x6. Problem is, it is in the heavy side. Power is amazing, thou, and I am now a 4s fan since this engine (my first 4s). I have now also a FS91 Surpass II and a new alpha series .81 (yes, you probably saw my post swearing I wouldn't expend that amount of money in this engine, I know....). Anyway...

My queestion:
I am now in the process of getting a new YS FZ63S, which also claims to turn te same prop at around 10,500, although with 20% nitro fuel. And I read here that the Alpha 56 also delivers around 10,000 RPM with the APC 13x6 with much less nitro. Both YS and Alpha are ligther than my trusty Surpass, so there is a good reason to get any of them, because even at the same power they would use less of that power moving the engine itself, right?

But I wonder, why too many of you consider the YS the "non plus ultra" of the pack if it delivers what seems to be the same power? Or is it? Does it means that the same RPM with the same prop IS NOT NECCESARILLY the same power? I will get one of those anyway, but honestly I wonder if I will note the difference...

Thanks a lot and regards.

Martin