The Ilya Muromets (Sikorsky S-22) was designed and constructed by Igor Sikorsky at the Russo-Baltic Carriage Factory (RBVZ) in Riga 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.
Russia had a chance to become the birthplace of the first multi-passenger and multi-engine airliner.
The Ilya Muromets was first conceived and built as a luxurious aircraft. For the first time in aviation history, it had an insulated passenger saloon, comfortable wicker chairs, a bedroom, a lounge and even 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 which included a berth, small table and a cabinet. Lighting was provided by a wind-driven generator and heating was supplied by two long engine exhaust pipes which passed through the corners of the cabin. Despite many advancements, the flight instruments on the Ilya Muromets were primitive. They included four tachometers, one per engine, a compass, a crude altimeter and airspeed indicator, two glass V-shaped tubes and a ball for bank indication, and a series of horizontal bars situated vertically on the nose of the fuselage for measuring climbs and descents. Later, in the bomber variants, a drift indicator and elementary bomb sight was added to aid bombing.
On 10 December 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. 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.
With the beginning of World War I, Sikorsky was encouraged by the results of the proving flights to redesign the aircraft to become the "Military Ilia Mourometz, Type V, the world's first purpose-designed bomber. 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 engines were protected with 5 mm-thick armor. The military version was designed expressly for long-range flying in both bombing and reconnaissance roles.