Oct 042011
 
Stiller Helicopter Project of 1928

On January 1, 1928, brothers I. and J. Stiller, both of whom were engineers living in Radom, Poland, filed a patent in Warsaw for a peculiar helicopter design featuring two small propellers fitted on the upper end of swiveling shafts arranged in parallel. These propellers were driven by an internal combustion engine located between the shafts. […]