This little Chinese twin only weighs 3.75 pounds, including the mufflers and ignition. But I agree, 50cc is the very bottom end of the range, and I would recommend the upper end of the range, given what I've seen on the 1/4 scale D-VII. It will fly on a G-26, but no power reserve and performance is marginal. With a G-38, though, it is a great performer.

If you go with a good 80cc single you should hit the mark. The Super 80 ZDZ would be an awesome engine., also give you the ability to spin a large prop.