Is the the engine you are looking at?
http://www3.towerhobbies.com/cgi-bin...1&I=LXRAW2&P=3
If yes, it is probably something you'd consider for some 1.20 size models.
It weighs 3.2 pounds (around 51 ounces) including muffler
It needs a 16x8 or 16x10 prop


Weight will be the killer for smaller planes. The majority of glow engines in the .61 to 1.00 range weigh 20 to 25 ounces.

The Zenoah G20 (41 ounces including muffler and ignition) is supposed to be a good match for the round cowl, 60 size, Hangar 9 warbirds because they have a short nose and tend to need extra weight up front. Horizon says it spins an APC 15x6 at 9500 rpm.

There is a Saito 1.25 (20cc) four stroke gas engine that weighs 30.1 ounces with muffler and ignition.