I agree that a .10 would be a much better choice, and that an .049 would probably be marginal.

There are many other considerations and design changes that you will have to do, since the plane wasn't really designed to be powered by an engine, but a rubber band, instead. I imagine the firewall (if there even is one) will probably have to be beefed-up, as well as some of the fuselage structure to which the firewall attaches.

And then the balance issue, where I imagine you would have to mount all of the radio gear as far rearward as possible.

The kit may not even come with operable control surfaces. In that case, some serious design changes would be required.

I'm not sure how available fuelproof dope, etc. is anymore - something else to consider.

I'm just guessing on most of this, because I haven't built that type of kit in over 45 years, and I recall very little. I have thought of doing a project like this, as there are some very cool kits out there that could become incredibly cool small r/c models. But I realized all of the challenges, and didn't want to just jump into it.

I imagine quite a few people have attempted a project like this, so hopefully they will eventually chime in and give their experiences.

I love seeing the hobby of building r/c planes staying alive. This aspect of the sport is dwindling away and dying, but some of us are trying to keep it alive. In other words....you go, girl!!!