I am guessing it is for a nitro motor. (I do believe MA makes props for electrics as well)
Any of the standard size, 40 size trainer will do. By standard size I am talking about 60"ish wing span. The larger 40 size trainers with 70" plus wingspan are happier with a slightly larger engine .46 or so.
You my friend would want a 40 size engine for that prop like OS 40LA maybe. Even a .35 or so if you get a smaller trainer.
I do have to say this is the first time I have seen someone wanting to build an airplane around a propeller
Good luck