ORIGINAL: ChuckW
Zenoah and Fuji are both outstanding. Desert Aircraft is another good one. I am really impressed with the DLE's too and plan on using one on a current project. Even some of the ''no-name'', low cost Chinese engines run very well for the money.
I would not be concerned about fighting to make a gas engine run. If somebody was struggling that bad with one then there was either something wrong with it, it was set up improperly or he did not know what he was doing. Gas engines are almost always easy to start, run great and don't require a lot of fiddling once the carb is adjusted.
For that 3D plane, take alook at the DLE-30. If you want something larger, there are plenty of 40-43cc engines out there. That Fuji-43EI is a little pricey but it is one of the most reliable, best running gas engines I have seen.
Hmmm. most gas engines start on two flips of the prop or less. I flip mine once with the choke on, and then once with the choke off. Keep in mind that most now have EI systems that require an additional switch and 4.8 battery. Or you can find and older US or quadra that use the magneto ignition. You should also use an opitcal kill switch for a gaser, though some install a servo on the choke, This gives you the ability to shut the engine down in flight in case something goes wrong with the engine, but you can still dead stick the plane in for a landing. Most fields require some method of killing the engine from the radio for gasers.