Hi,

First… don’t look at the wing span… look at the wing area. And, look to see what the flying weight should be. That should decide what motor you will run. If your model is around 1300 sq in, and over 11 Lbs (just a guess for 80”)… then you will want to go with a GOOD 25cc engine (Toro or an Echo) or bigger. And tim220225’s suggestion is right for the props.

Now for you question on small engines…

Yes… most small (less than 23cc) engines have been known to be low output for their weight. But, I have stumbled on to a few 19.8cc Mitsubishi engines from John Deere weedeaters, and they are absolutely great for their size. They are much lighter than the 23cc engines that are out there, and they can swing a 16x6 at 7600 RPM. (no mods) And, the flywheel is very small and light. (not worth converting to electronic)

Here are a couple pics of one stuffed into a Hanger9 Frenzy 100 (61” span) Just as an FYI… the flying weight is 8Lbs, 7oz.