It has been done, you can buy Chinese made very light 2 stroke engines packaged with a generator. Used for large hexes and octocopters. Incredibly noisy and the lightweight design of the engine means it has a very short time in hours operating before rebuild.
These are a known thing from like three or four different vendors in the community of people who build medium to large sized ardupilot/arducopter based things.
These are a known thing from like three or four different vendors in the community of people who build medium to large sized ardupilot/arducopter based things.