ORIGINAL: GaryHarris
Glow has more power to weight ratio since its burning Methanol and Nitromethane. Obviously it cost's more to run than gasoline. I don't think gas engines have an advantage until you start getting into large planes.
I dunno..
With the newer 15cc and 20cc engines even smaller planes benefit from going gas, especially when you consider that Gas is so much cheaper than nitro, and the gas engines effectively have their own pumps...
You don't have to worry about muffler pressure, changes in HS needle settings to deal with nose high conditions, etc... once the engine is tuned, you pretty much forget about the needle valves on the carb.
The power to weight on these small engines is pretty impressive, rivaling glow due to the light CNC aluminum machining.
You can also by them ready for beam mounting so they will drop into most glow ARFs.
Performance has been great on my .60 and 1.20 sized planes rivaling oversized glow engines with few drawbacks.
The downside is that you have to worry about charging the ignition battery...