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-28 Sikorsky S-28 The Sikorsky S-28 was a proposed four engine biplane bomber aircraft designed by Igor Sikorsky to be built in France during World War I. Sikorsky moved to France in March 1918 and soon met with officers of the "Armée de l'Air" who asked him to design an aircraft capable of carrying a new 1,000 kg (2,200 lb) bomb. Although the aircraft was initially designed to be powered by two Liberty L-12 engines, the technical section of the "Armée de l'Air" suggested using four Hispano-Suiza 8 engines instead. By early August 1918 Sikorsky's plans were completed and the project