BLW, I find hard to believe that someone get 10 spare (quite expensive) engines to any contest, even if sponsored...

But anyway, the intention of the post was more likely to compare real power, in terms of RPM with same prop. I know there are lots of other issues to consider, like engine cost, fuel cost, reliability, tunning complexity, costs of parts, etc.

To be honest, in my case the fuel cost is what worries me more. But my point was, if (from I read in several posts) those three engines could turn and APC 13x6 at or around 10K, then why bother? The answers I got showed me that this is not quite true, and that the 56 Alpha could be at 10K, the 70 Surpass II delivers 10,500 (that I know for a fact) and that YS63 could turn the same prop at more thatn 11 + K, which means it has more power.

I for sure will get the YS, and I will probably get an alpha 56. Then I will see by my own test, considering my very basic tunning skills, which I hope will not spoil the final observations.

Then, with the final results, anyone could choice whatever he likes in terms of spare parts, or aquisition costs, or fuel costs, or as in my case, true weight.

Thanks and regards

Martin