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-16 delivered in early 1916. Although highly maneuverable, the S-XVI possessed a comparatively poor performance due to insufficient power. A further small batch were completed in 1917, with the aircraft being used during the Russian Revolution and staying in service until 1923. At least one aircraft have been used by the Ukrainian People's Republic after 1917. Sikorsky S-16 The Sikorsky S-16, or RBVZ S-XVI (named after its manufacturer), was a Russian equi-span single-bay two-seat biplane designed by Igor Sikorsky in 1914-15. Conceived in response to demand for an escort fighter for the Ilya Muromets bombers, it was noteworthy in that it