Good size for a 26"?

I'm gonna guess ... 049 SureStart.
Change the prop to fit the mission.

If you can take a guess as to the area, or post a plan even a cellphone camera pic of a napkin with your plan, the gang here can crunch all the engineering with you. You gonna use a bunch of sheet balsa or a whole bunch of stick. You going for speed or relaxing simple loop/roll. Some will even help fit engines to the blue FFF planes

Or take the shortcut: We look at a similar plane and see what worked on it.