They were discussing that MAN engine article way back in 2003 in this thread here:
http://www.rcuniverse.com/forum/m_65.../tm.htm#658084
this looks like a reprint of the magazine article too:
http://findarticles.com/p/articles/m...5/ai_n9251269/
Now I know what I did wrong in checking RPMs on my engines a while back. I have been using 11x7 Zinger wood props, and they are harder on a engine to turn than a wimpy little APC 11x6 prop. I normally use 11x6 props on my Fox 45 and 50 engines and 11x7 and 11x8 props on my .60 engines. I remember getting around 12,500 RPMs with a 11x6 Master Airscrew prop on one of my venerable Fox 45 engines recently. But my .60 engines were all running around 11,000 rpms with a 11x7 Zinger prop. But my old Fox Hawk .60 did turn around 12,000 rpms with the 11x7 prop but it has been very well broken in though. I tried a cheapie ASP .61 and it was impressive in that it turned the 11x7 prop at around 12,300 rpms with the stock muffler too. I was only using 5% nitro Omega fuel too.
anyway I guess I should have under propped the engines to get these higher RPMs out of the engines.
In my opinion it will be next to impossible to duplicate any performance numbers someone pusblishes as you don't have their exact propeller that they used. You want all the engines to use the same propeller, as each propeller is a a little different from the next one. The same engine test stand as vibrations from the engines can rob them of power, so you want all the engines to have the same engine test stand too. Then the engines all have to use the same fuel. Then they all need to use the same glow plug (as variations from plug to plug exist, but with new engines you can contaminate and or blow out a plug prematurely too. Finally you have to have the same environmental conditions too, weather, temperature, humidity, barometric pressure. Factors like altitude can affect the results as well.
I also suspect some manufacturers of fudging or lying about their results. One can shave or sand down a propeller to make it a little more thin or shaped differently. Thus one could get the engine to turn most any RPMs that you want it to.