what engine are you going to use on it?

the H9 makes a 27% now with I believe a 80" wingspan

the old discontiued 1/4 cap 232 was a very nice plane

For the 73 in Cap, a 3W 24 would be good. It has 3 horspower and can have 4 with a tuned muffler, and the Saito 180 has 2.8. You could put the 3W 42 on it, but it would be heavy.

or a F.P.E. 2.4 which i believe is rated at 4 hp


for the 80" cap a BME 50 would be awsome for it but then again you already have the engine