[PDF via NewAtlas] Inspired by some of the experiments with “ring wings” in the early 20th Century, researchers iterated on various toroidal propeller geometries until arriving at one that ...

Most famous of these is probably the toroidal propeller that made waves a while ago, mostly in the field of flying drones, but commercial toroidal boat props exist too. Test results of the ...

The development of advanced turboprop geometries like counter rotating open turboprop configurations ... In order to reach that goal a detailed knowledge of the highly unsteady flow around and in the ...