Flying disc or "frisbee" like device I made a while back. The idea is to convert the spin to lift so it functions like a cross between a flying wing and a helicopter. While it was designed to be used with the flat side facing down, in practice it seems to fly much better with the flat side up (not sure why). But try it both ways and see for yourself.

It can be scaled to the desired size and should be printed with a layer height such that the airfoil is smooth.