Well, going to gas in a smaller model will likely cost you a weight penalty. But, many newer gas engines are lighter than ever and provide as much power or more than a glow engine of similar weight.

In general, the weight penalty disappears at 50cc. In a smaller model like yours, consider the weight of the engine verses power in pounds of thrust for comparison.

You will probably want a 30cc gas engine or bigger, depending on weight. Remember, you want the plane to balance properly without adding weight to the tail or the nose. Look at the largest recommended engine and use that as a weight limit. When you make comparisons, remember to add the weight of mufflers, ignition battery, ignition and anything else that may be needed.

Gas is by far cheaper and easier than glow, but in your model's size range you may have to settle on a slightly heavier engine.

Good Luck!!