Viktor Schauberger (1885-1958) was an Austrian engineer who studied the forces of water and water vortexes which led to a number of discoveries and ideas about energy that has today earned him a status similar to Nicola Tesla's in the world of "alternative science" and you can check a great site about him here.
Schauberger is often mentioned in connection to UFO and conspiracy theories and this comes from the fact that in the 1940'she worked under German military control on the devellopment of a flying machine called the Repulsine, which was based on his principles of creating energy from vortexes.
Schauberger was reluctant to work for the Nazi regime, which at one time placed his research under the direct control of the SS and dispatched him to the Mauthausen concentration camp where he was ordered to continue his work with the aid of forced labourers.
After WWII he was invited to the USA by a group of industrialists, but after spending some time working on projects in Arizona, he mysteriously signed a letter giving up any further research, handed over all his prototypes and notes and returned to Austria where he died four days later.
In 2006 the French engineer Jean-Louis Naudin built a working model based on the ideas of the Repulsine, you can see it fly here:
Podcast Coanda effect flying saucer by Jean-Louis Naudin
Panzer Jagdtiger in color
Not my people
Not my war