well i had it on another seaplane that was plan built and designed around a .25 but i went something closer to .40, then plane moved along very quick, it weight 5lb, the only reason i never flew it after general taxi tests is that it has a flaw in its old design and would dig its outer wing floats in once on plane. The World Models piper is 5.5lb at 71inches. Im not great with electrics and I remember choosing this set up for being close to a .40 size if this helps at all. Plus i think it has an 11x6 prop on it