Igor Ivanovich Sikorsky studied Paris 1907, returning to Kiev with Anzani engine used in unsuccessful coaxial helicopter. Followed with better and more powerful helicopter, almost flew. Turned to aeroplanes; BIS-1 (Bylinkin, Iordan, Sikorsky) used 15-hp and then 25-hp Anzanis (ex-helicopter), rebuilt as BIS-2, flown by Sikorsky 11 June 1910. Modified into Sikorsky’s own S-3 (November 1910), S-4 (December 1910) being larger version built for A. A. Gomberg who had 50-hp Anzani engine. S-5 (April 1911) had 50-hp Argus. With S-6 (100-hp Argus) Sikorsky took 3 passengers, and S-6A (March 1912) flew at 66 mph (106.2 km/h) with 4 passengers, later taking 1st prize at St Petersburg military competition. As result Sikorsky appointed designer at new aviation department of RBVZ (Russo-Baltic Wagon Works), designing world's biggest aeroplane, Grand, 2 x 100-hp Argus, flown 2 March 1913. Later fitted with 2 extra engines as pushers and finally with 4 tractor engines, renamed Russki Vityaz. Led to unique series of 4-engined reconnaissance and bomber aircraft all called IM (from Ilya Mourometz), 80 being built 1913-18 in 6 main versions with 7 types of engine. At Revolution Sikorsky left with what he could carry, spent a year in Paris, where he would have produced aircraft but for Armistice, then to USA.