There is a new .049 out there now. The Profi .8cc is in the hands of a number of people at this time. If you think you have seen a high performance .049 then take a deep breath. The latest version has raised the RPM bar almost 3000 from the first. Enough people have had a chance to do some testing and almost everyone has found well over 1000 more rpm than the very best example of the two popular 1/2A combat engines. This thing is a bit of a surprise when you first start running it. And it is turning FF propellers as well, no need for 4.25" props anymore. One common prop people have is the APC 5.5x2.5 FF prop. 15% Nitro is getting 31,700rpm and with 40% we can get 34,000. The Horsepower peak now seems to be in the area of 32K-33K and is requiring more load or larger diameter props. Our combat airplane is a little bit crazy on 42' lines! Check it out a www.flycontrolline.com
Judith/Profi America

That sounds pretty sweet! Will have to try one out