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
Igor Sikorsky several former Russian military officers. Among Sikorsky's chief supporters was composer Sergei Rachmaninoff, who introduced himself by writing a check for US$5,000 (approximately $61,000 in 2007). Although his prototype was damaged in its first test flight, Sikorsky persuaded his reluctant backers to invest another $2,500. With the additional funds, he produced the S-29, one of the first twin-engine aircraft in America, with a capacity for 14 passengers and a speed of 115 mph. The performance of the S-29, slow compared to military aircraft of 1918, proved to be a "make or break" moment for Sikorsky's funding. In 1928, Sikorsky became