Sikorsky Aircraft and soon increased prize money to US$25,000. In 2010, Sikorsky Aircraft pledged to increase the prize sponsorship to US$250,000. The Canadian engineers Dr. Todd Reichert and Cameron Robertson developed the world's largest ever human powered helicopter with a team from the [[University of Toronto]]. The first flight of AeroVelo Atlas was achieved in August 2012, the 64-second, 3.3-m-flight that won the prize on June 13, 2013. Sikorsky designates nearly all of its models with S-numbers; numbers S-1 through S-27 were designed by [[Igor Sikorsky]] in the Russian Empire. Later models, especially helicopters, received multiple designations by the military services using
Sikorsky S-19 Sikorsky S-19 The Sikorsky S-19 was a Russian twin engine experimental prototype aircraft built late in 1916 by the Russian Baltic Railroad Car Works while Igor Sikorsky was chief engineer of the aircraft manufacturing division. The S-19 was a two bay sesquiplane powered by two Sunbeam Crusader water-cooled V-8 engines installed in push-pull configuration. Arranged as a twin-boom aircraft, it had a large rudder located in the center of the empenage. Two crewmembers occupied cockpits in the foreword most section of the booms in front of the lower wing and served as pilot and machine gunner. Flight testing revealed sluggish