I was explaining to a friend that I read an article about these vanes that were positioned behind a turbine blade on a jet engine to try to straighten out the airflow which is supposed to help increase the thrust. I have seen the same sort of thing sold for hovercraft ducted fans. My friend wanted to know why they didn't use two propellers. One spinning clockwise and one spinning counter-clockwise. I remember seeing a Russian helicopter that was imported into Canada for the

purpose of selective harvesting of trees from hard to reach areas. The advantage of the dual counter rotating blades was that these helicopters had much shorter blades and twice the thrust. Plus they did not require a tail rotor and could operate in very windy conditions and face any direction regardless of wind direction. So, that got me thinking. <By now, you probably have noted that I do a lot of thinking> Has anyone ever seen such a setup on a light aircraft or hovercraft? It might actually be an interesting idea to try. I am not too sure how to design it but it would certainly be an interesting test.