Yakovlev Yak-12

The Yakovlev Yak-12 (Russian: Як-12, NATO reporting name: "Creek") is a light multirole aircraft used by the Soviet Air Force and Soviet civilian aviation from 1947 onwards.

Yak-12M

History

The Yak-12 was designed by Yakovlev's team to meet a requirement of the Soviet Air Force of 1944 for a new liaison and utility plane, to replace the obsolete Po-2 biplane. It was also meant to be used in civil aviation as a successor to Yakovlev's AIR-6 of 1934, built in a relatively small series. Yakovlev's first proposal was a 4-seater high-wing Yak-10 (first named Yak-14), built in January 1945. It won the competition with a low-wing Yak-13, based on the same fuselage, and a small number of Yak-10s were produced, powered with a Shvetsov M-11M radial engine (108 kW, 145 hp).

In 1947, the aircraft was rebuilt, fitted with a more powerful M-11FR radial engine (119 kW, 160 hp), a new wing and a fuselage with a revised shape. The new plane was designated Yak-12. 788 were produced of the basic variant, including military observation planes, some Yak-12S flying ambulances , Yak-12SKh agricultural aircraft and Yak-12GR floatplanes. A distinguishing feature of the basic Yak-12, just like Yak-10, were engine cylinders with individual cowlings. It was a plane of mixed construction.

A next generation of Yak-12s entered production in 1952, starting with the Yak-12R. It was fitted with a new Ivchenko AI-14R radial engine (194 kW, 260 hp), all hidden in the fuselage, and the plane construction became all-metal. After further construction strengthening and other minor changes, from 1955 the Yak-12M (for "modified") was produced. A visible difference was a lengthened tailfin. This variant became more universal, and could be fitted with twin controls for training, stretchers for an ambulance role or agricultural spraying device.

The last generation, produced from 1957, was the Yak-12A. It was an aerodynamically refined variant, with a slimmer fuselage. The engine cover had a smaller diameter. The rectangular-shaped wings were fitted with trapezoidal ends, and single struts replaced twin struts. Navigation equipment and controls were improved, and performance also increased. In the USSR, 3,801 of Yak-12s were built in all models (including 3,013 Yak-12R, M and A). An experimental Yak-12B biplane was also developed, but not produced.

The Yak-12M was licence built from 1956 in Poland as the WSK-4 Okecie, or Jak-12M. From 1959, the Yak-12A was built in Poland as the Jak-12A. 1,054 Jak-12Ms and 137 Jak-12As were built in Poland, most exported to the USSR. In 1958, further developement of the Yak-12 was carried out in Poland, designated as the PZL-101 Gawron.

The Yak-12 was also produced in China as Shenyang type 5.

Usage

Yak-12s first entered service in the Soviet Air Force as a liaison and artillery observation plane. Then, they were used also in the Soviet civilian aviation - mostly in the DOSAAF aero club for transport, pilot training, parachute training, and glider towing. They were also used as flying ambulances and agricultural planes.

Apart from the USSR, Yak-12s were used in Poland, Czechoslovakia, Yugoslavia - in civilian and military aviation, and in Hungarian civilian aviation. Licence built Shenyangs were used in China and other countries.

In the Polish Air Force, Yak-12s (transcribed in Poland as Jak-12) were used from 1951, as liaison, patrol and general utility planes. Most were withdrawn in the 1970s, the last in the 1980s. In the Polish civilian aviation they were used from 1952, in bigger numbers from 1956. They were used in aeroclubs and as flying ambulances.

Some Yak-12s (mostly Yak-12A) remain in use until today (2004) in the world's civilian aviation.

Description

Metal construction (Yak-12R, M, A) or mixed construction (Yak-12) braced high-wing utility plane, conventional in layout, metal and canvas covered. Wings fitted with flaps and slats. Four seat cabin (in early variant Yak-12 - 2 or 3 seat). Conventional fixed landing gear with tail wheel.

Single radial engine: 5-cylinder M-11FR (nominal power 104 kW/140 hp, take-off power 118 kW/160 hp) - Yak-12 basic variant; 9-cylinder AI-14R (nominal power 161 kW/220 hp, take-off power 191 kW/260 hp) - Yak-12R, M and A. Two-blade propeller. Two fuel tanks in wings, 225 l (55 US gal) each.

Specifications (Yak-12A)

General Characteristics

Crew: one, pilot
Capacity: 3 passengers
Length: 9.0 m (29 ft 6 in)
Wingspan: 12.6 m (41 ft 4 in)
Height: 3.12 m (10 ft 3 in)
Wing area: 22.6 m² (243 ft²)
Empty: 1,056 kg (2,323 lb)
Loaded: kg ( lb)
Maximum takeoff: 1,588 kg (3,494 lb)
Powerplant: 1x Ivchenko AI-14R air-cooled radial engine, 191 kW (260 hp)

Performance

Maximum speed: 215 km/h (134 mph)
Range: 1070 km (669 miles)
Service ceiling: 4,000 m (13,120 ft)
Rate of climb: 216 m/min (708 ft/min)
Wing loading: kg/m² ( lb/ft²)
Power/Mass: kW/kg ( hp/lb)