Weight is a good question... Lots of math and research is needed.
first, something is telling me the aircraft doesn't really meet the 254lb ultrlight weight standard. But I need to spend some time doing that math. There's also room to shorten the nose a little if I go way overweight with the engine.
Yeah, I'm 210lbs, which is 30lbs lighter than the test pilot at 28hp. And it's a goal to be under 180 come spring. We'll see if I can manage that.
My real reason for a light powerplant, and fuel efficient powerplant is to have the best performing plane I can have. Working with model airplanes has taught me very well that less weight is almost always superior to more power.
Many of this plan have flown, but nobody has published test numbers for it. Which is a little bothersome. I'd love to know it's sink rates at what airspeeds. I'd also like to know what the plane really weighs. And I'd like to know what "underpowered" means when flown on 28hp. with that motor, and me, in the plane, we'd be talking a plane that's a full 10% lighter than the test pilot and the recommended motor.