I had a Magnum 52 4Stroke on a Hanger 9 Cub with an 80" wingspan. I always felt that it was underpowered and didn't think the Magnum 4S developed as much power as an OS or Saito 4stroke engine.

I would stick to a 2 stroke myself. If really want to save fuel get a 20-25 sized plane. If you are like me when I learned to fly I went through a bunch of fuel just because I went flying 2-3 times a week.

Look at a Magnum 52 two strokefor less than a hundred bucks. I paid about $85 for the one I have. Its still new in the box and waiting on me to build a plane for it. I have a Krafty 60 kit just waiting to be built.

I look on Ebay for model stuff. I have bought two NIB engines off there for really low prices. AnOS FP25 and a TT 40 both for$40 each. An OS FP60 just sold for $55 IIRC a week ago. It was also new in the box. Lots of people are selling their glow fuel planes and motors and going all electric so motors aren't as valueable as they once were. That works for me. I have no interest in electric motors.

And don't turn your nose up at the plain bearing engines with thier air bleed carbs. They work just fine and are super easy to adjust. I sort of prefer them when can get a deal on them. And they sell cheap.