Ilyushin Il-12
| Il-12 | |
|---|---|
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| Ilyushin Il-12 of CSA Czechoslovak Airlines on a scheduled service at Paris Orly Airport in 1957 | |
| Role | Transport aircraft |
| Manufacturer | Ilyushin |
| First flight | 15 August 1945 |
| Primary user | Aeroflot |
| Produced | 1946-1949 |
| Number built | 663 |
| Variants | Ilyushin Il-14 |
The Ilyushin Il-12 (NATO reporting name: Coach) was a Soviet twin-engine cargo aircraft, developed in the mid-1940s for small and medium-haul airline routes and as a military transport.
The Il-12 was developed as a private venture by the Ilyushin Design Bureau from autumn 1943 and was intended as a replacement for the Lisunov Li-2, a license-produced version of the Douglas DC-3. The new aircraft followed a classical layout for a twin-engine transport, with a metallic structure, monoplane wings, a conventional tail section. One major improvement over the Li-2 design was the tricycle landing gear, which allowed better visibility when taxiing and landing. Initially the Il-12 was designed for 29 passengers in a pressurized fuselage, with projected maximum range is assumed of 5,000 kilometers at a cruising speed 400 kph. The aircraft was to use four M-88B engines already proven in use on the Ilyushin Il-4.
However, during development, the M-88B engines had to be replaced by two ACh-31 diesel engines (each producing 1,500 hp). The plans for a pressurized fuselage were abandoned and the number of passengers reduced to 27. The Il-12 made its maiden flight on 15 August 1945. It was soon decided to re-engine the aircraft with Shvetsov ASh-82 radial engines with the revised aircraft flying on 9 January 1946.
The Il-12 was found to have problems with vibration during testing, having poor engine out characteristics and requiring a strut under the rear fuselage to prevent tipping during loading due to center-of-gravity problems. Further problems was the use of magnesium near the engines which in case of engine fire could cause an uncontrolled fire, damaging the wing structure. (This was later revealed by a crash of an Ilyushin Il-12 near Voronezh which killed all on board, following an engine fire. Subsequently, as a result of the accident investigation, the magnesium was replaced by aluminium alloys and the fire extinguishing system was redesigned.) However, once these problems were resolved, factory test pilots praised the quality of the new aircraft, which contributed to the decision to launch the Il-12 in series production.
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