The Ilya Muromets (Sikorsky S-22) was designed and constructed by
Igor Sikorsky at the
Russo-Baltic Carriage Factory (RBVZ) in
Saint Petersburg in 1913. It was based on his earlier S-21
Russky Vityaz, which started out as the twin-engined
Le Grand, then as the twin tandem-engined
Bolshoi Baltisky before placing all four of the ''Baltisky's'' engines in a
tractor configuration along the lower wing's leading edge to create the Russky Vityaz — which had played an important role in the development of Russian aviation and the multi-engine aircraft industries of the world. The Ilya Muromets was first conceived and built as a luxurious aircraft. It was the first aircraft to have an insulated passenger
saloon, containing wicker chairs, a bedroom, a lounge, as well as the first airborne toilet. The aircraft also had heating and
electrical lighting. The S-22 cockpit had sufficient space allowing several persons to observe the pilot. Openings on both sides of the fuselage permitted mechanics to climb out onto the lower wings to service the engines during flight. A hatch on the left side provided an entry to the main cabin, behind the cockpit. The main cabin featured two large windows on each side. Further back was a private cabin that included a berth, a small table, and a cabinet. Lighting was provided by a wind-driven generator and heating was supplied by two long engine exhaust pipes that passed through the corners of the cabin. Later, in the bomber variants, a drift indicator and elementary bombsight were added to aid bombing. In 1913 the Ilya Muromets No. 107 flew for the first time, and on 11 February 1914, the second prototype (factory airframe 128) took off for its first demonstration flight with 16 passengers aboard, marking a record for number of passengers carried. From 30 June to 12 July 1914, it set a world record by making a trip from
Saint Petersburg to
Kiev, a distance of some 1200 km, and back. The first leg took 14 hours and 38 minutes, with one landing for fuel at
Orsha, and the return one, with a fuel stop at
Novosokolniki, took even less time, about 13 hours. According to Sikorsky, "The flight proved conclusively the value of large multi-motored airplanes. The Army placed an order for ten four-engined airplanes of the
Ilia Mourometz type and the factory personnel was overjoyed by this final approval of the results of two years of hard work." The acclaim received by Sikorsky included
Tsar Nicholas II presenting him with the
Order of St. Vladimir, Fourth Degree, arranging for an exemption from the wartime draft to allow him to continue his design work, and a promise of a grant worth 100,000 rubles from the State Duma. During an Imperial military review at
Krasnoye Selo in July, Nicholas II decorated and christened the Ilya Muromets Type B Military Prototype, No. 128, the "Kievsky." During testing, the Ilya Muromets were fitted with both skis and pontoons in anticipation of new variants being produced. If it had not been for World War I, the Ilya Muromets would probably have started passenger flights that same year. The new heavy bomber was slightly smaller and lighter than the Type A. Internal racks carried up to 800 kg of bombs, and positions for up to nine machine guns were added for self-defense in various locations, including the extreme tail. The Muromets (in its S-25 Geh-2 variant, March 1916) was the first aircraft in history to incorporate a
tail gunner position. The engines were protected with 5 mm-thick armor. The military version was designed expressly for long-range flying in both bombing and reconnaissance roles. == Operational history ==