Sikorsky conceived the S-21 design in 1911, when no known aircraft could lift more than. The carrying capacity record belonged to the French pilot Ducis, who had flown with a load of. On hearing about the construction of the Russky Vityaz in early 1913, the experts and the mediaaround the world were predicting a complete failure. The first aerial test of the Russky Vityaz on 10 May 1913 was successful. At the time, many people in other parts of the world considered it to be a newspaper hoax, and did not believe it. Observers believed that an aircraft of such dimensions would never leave the ground.
Design
The Russky Vityaz was a four-engine multi-bay biplane with unequal-span wings. The dual-spar wings had a rectangular planform and a chord of. The distance between the wings was also. Its fuselage was a rectangular section girder, covered with plywoodsheets. The aircraft had a cabin with a dual control column, two passenger cabins and a storage room for spare parts. There was also an open deck forward of the pilot's cabin equipped with a searchlight and machine gun. The ailerons on the upper wings provided for the airplane's stability. The first quadruple-engined version of what was to become known as the Russky Vityaz, when it was known as the Bolshoi Baltisky, was powered by four engines installed in tandem pairs. The Russky Vityaz moved the twin pusher engines from the Bolshoi Baltisky's layout onto the leading edge of the lower wing as tractor configuration powerplants, outboard of the original inner tractor configuration engines.
Operational history
After the Russky Vityaz's first test flights between 10 and 27 May 1913, it was established that a passenger could even walk around the cabins without causing any problems to stability. The aircraft left the ground after a takeoff run. Sikorsky's aspirations for the Russky Vityaz proved to be short-lived. While parked on the runway on 23 June 1913, the aircraft was crushed by an engine that fell off a single-seat Morane aircraft during a landing. Sikorsky decided not to repair the seriously damaged Russky Vityaz and began working on his next brainchild — the Ilya Muromets.
