large propellers

Hi. I need a heavy lifter that can lift 10lb with a decent TWR for a few minutes, and I want to make it as cheap as possible within those constraints. I'm aware that cheap is relative and this will probably end up >1k on the low end. The entire purpose of this thing is to fly straight up, drop...

After watching countless hours of videos and listening to others complain that the noise is too much for the neighbors, I would really like to know what the ramifications are of putting a huge prop on a small plane. I am talking a prop with a diameter that is 40-50% the length of the wing...