06/05/2005. Remarks by Johan Visschedijk: "Joining the Aviation Department of the Russo-Baltic wagon factory in mid-1912 Igor Sikorsky was about 24 years of age when he started to design this for its time large aircraft. First flown in December 1913, a total of 80 of these machines were eventually built in six main versions but differing in many details. The aircraft were being used for reconnaissance and strategic bombing, after WW I as trainer and transport."