Thanks all of you for the answers.

Liquid TR: 11,400 RPM is definitely more than my 70 Surpass II could do, so I guess the YS 63 has more power after all.

However, I saw a 91 Surpass turning an APC 15x6 close to 10,000 at 10% nitro. Mine is not break.in yet, so I couldn't tried by myself. I don't expect the YS 63 turns a 15x6, as I don't expect it either turn a 14x6 at a decent RPM. My Surpass 70 does a good job with an APC 14x6 at 10% also.

I will get the YS63 in a couple of weeks, and I will try every conbination with the props I have in hand.

Thanks and regards

Martin