I thought about the 4.2 too, even cutting it down to 3" and leaving it 4" pitch. The plane is light enough to get a good launch on a 3" thrust and it just might come up on pipe in a dive. Don't know unless you try. I know they say no electric props on glow but they have some small speed props made for 31k motors and I can't see where a 020 is realy going to rip it limb from limb. The electric motors have instant tourque which I think would be much harder on the prop.