The tail of the Great Planes Super Sportster 90-120 kit may not be "reliable" when you use a gasoline-powered, high-vibration engine. The model was designed for 90-120 size glow two-stroke glow engines. Usually, the .90-size two-stroke engine is plenty of power, and a 1.20-size four-stroke engine works nicely, too. If you go to a gasoline engine, not only are you adding higher levels of high-amplitude vibration, but you are adding a LOT OF WEIGHT. The model was flat-out not intended to support that much weight from the firewall. The O.S. Max 1.08FSR was an ideal engine.

The ARF version is different, and up to a 32cc gasoline engine can be used.