Hi All!

Is there any "formula" to use when selecting an engine for your plane. Should you use a certain size based on weight, or wing span, etc......

I have a Cessna Skymaster (Royal Kit) that I need to purchased engines for - I have read the other post on this plane but all seem to have different sizes that they are running.

Any help would be greatly appreciated.

Calvin

It is usually a good idea to fit the largest size recommended by the manufacturer.

I don't have the plans for this plane, but I think that the manufacturer did recommend up to a .61 2 stroke - what 4 stroke would be equivalent?

An 80-ish something or other would do nicely

The Saito 72 is an excellent motor. The 82 has a reputation as a real vibrator. We used to figure that a 4 stroke had 60% of the power of the same displacement 2 stroke. It was even in contest rules that way. But that isn't nearly as true as it was in 1980, and maybe not true at all. As you're shopping, be sure to compare the weights of the different motors. Six or eight extra ounces in the nose is a pain to make up for. And scale planes sure benefit from being light.