Yakovlev Yak-11

Yak-11
Yak-11
	Let C-11
General information
Type	Training aircraft
Manufacturer	Yakovlev, Let
Primary user	Soviet Air Force
Number built	4,566
History
Introduction date	1946
First flight	10 November 1945
Retired	1962

The Yakovlev Yak-11 (Russian: Яковлев Як-11; NATO reporting name: "Moose") is a trainer aircraft used by the Soviet Air Force and other Soviet-influenced air forces from 1947 until 1962.

Design and development

The Yakovlev design bureau began work on an advanced trainer based on the Yak-3 fighter in mid-1944, although the trainer was of low priority owing to the ongoing Second World War.^[1] The first prototype of the new trainer, designated Yak-UTI or Yak-3UTI flew in late 1945. It was based on the radial-powered Yak-3U, but with the new Shvetsov ASh-21 seven-cylinder radial replacing the ASh-82 of the Yak-3U.^[2]^{[nb 1]} It used the same all-metal wings as the Yak-3U, with a fuselage of mixed metal and wood construction. The pilot and observer sat in tandem under a long canopy with separate sliding hoods. A single synchronised UBS 12.7 mm machine gun and wing racks for two 100 kg (220 lb) bombs comprised the aircraft's armament.^[3]

Let C-11

An improved prototype flew in 1946, with revised cockpits and a modified engine installation with the engine mounted on shock absorbing mounts.^[2] This aircraft passed state testing in October 1946, with production beginning at factories in Saratov and Leningrad in 1947.^[4]

Production Yak-11s were heavier than the prototypes, with later batches fitted with non-retractable tailwheels and revised propellers. A 7.62 mm ShKAS machine gun was sometimes fitted instead of the UBS, while some were fitted with rear-view periscopes above the windscreen.^[4] Soviet production totalled 3,859 aircraft between 1947 and 1955, with a further 707 licence-built by Let in Czechoslovakia as the C-11.^[5]

Yak-11U

In 1951, Yakovlev revised the design of the Yak-11, adding a retractable tricycle landing gear, with two variants proposed, the Yak-11U basic trainer and Yak-11T proficiency trainer, which carried equipment similar to contemporary jet fighters. The new aircraft had reduced fuel capacity and was unsuitable for operations on rough or snow-covered runways, and so was rejected for Soviet service, although a few units were built in Czechoslovakia as the C-11U.^[6]

Operational history

Egyptian Air Force Yak-11

The Yak-11 entered service in 1947, serving as a standard advanced trainer with the Soviet Air Forces and DOSAAF.^[7] Both the Yak-11 and C-11 were used in all Warsaw Pact countries and were exported to eighteen countries, including many African, Middle Eastern and Asian countries.^[4]

Egyptians used the aircraft extensively during their intervention in the Yemeni Civil war. Egyptian aircraft were modified with Sakr 78mm unguided rockets and two .303in guns in the wings. and were used in the ground attack role.

North Korean Yak-11s were used in combat in the Korean War, with one Yak-11 being the first North Korean aircraft shot down by US forces when it was destroyed by a North American F-82 Twin Mustang over Kimpo Airfield on 27 June 1950.^[8] East Germany used the Yak-11 to intercept American reconnaissance balloons.^[7]

Surviving aircraft

Heavily modified Yak-11 used for air racing

Due to its Yak-3 lineage, the Yak-11 has recently seen widespread popularity among warbird enthusiasts. Highly modified versions of the Yak-11 are often seen at air races. About 120 Yak-11s remain airworthy.

Operators

Yak-11 operators

Fighter/trainer aircraft Yakovlev Yak-11 (National People's Army)

Preserved Yak-11 of the Polish Air Force

Yakovlev Yak-11 disguised in wartime fighter camouflage

Afghanistan

Afghan Air Force − Received 12 in 1955.^[9] Operated an unknown number as late as 1981^[10]

Albania

Albanian Air Force − Received 6 in 1953^[9]

Algeria

Algerian Air Force − 12 ex-Egyptian aircraft delivered in 1964, possibly modernized in Czechoslovakia before delivery^[9]

Angola

National Air Force of Angola^{[citation needed]}

Austria

Austrian Air Force^[11] − 4 donated by the Soviet Union in 1955^[9]

Bulgaria

Bulgarian Air Force − 30 C-11 received in 1954^[9]

China

People's Liberation Army Air Force − 50 delivered in 1950^[9]

Czechoslovakia

Czechoslovak Air Force − 120, produced under license^[9]

East Germany

East German Air Force^[12]

Egypt

Egyptian Air Force^[13]

Iraq

Iraqi Air Force^[14]

Hungary

Hungarian Air Force^[15]

Mali

Malian Air Force − 4, non-operational by 2011^[16]

Mongolia

Mongolian People's Air Force^[17]

North Korea

North Korean Air Force^[18]

Poland

Polish Air Force − Received 40 in 1953^[9]

Romania

Romanian Air Force − Received 20 between 1952 and 1953^[9]

Somalia

Somali Air Corps − 20, non-operational by 1991^[19]

Soviet Union

Syria

Syrian Air Force^[20]

Vietnam

Vietnam People's Air Force^{[citation needed]}

Yemen

North Yemen Air Force − 30 donated by the Soviet Union between 1957 and 1958^[9]

Specifications (Yak-11)

General characteristics

Crew: two, student and instructor
Length: 8.20 m (26 ft 10.5 in)
Wingspan: 9.4 m (30 ft 10 in)
Height: 3.28 m (10 ft 5 in)
Wing area: 15.40 m² (166 sq ft)
Empty weight: 1,900 kg (4,189 lb)
Max takeoff weight: 2,440 kg (5,379 lb)
Powerplant: 1 × Shvetsov ASh-21 air-cooled radial piston engine, 521 kW (700 hp)

Performance

Maximum speed: 460 km/h (289 mph, 248 kn)
Cruise speed: 370 km/h (230 mph, 200 kn)
Range: 1,250 km (795 mi, 691 nmi)
Service ceiling: 7,100 m (23,295 ft)
Rate of climb: 8.1 m/s (1,600 ft/min)
Wing loading: 161 kg/m² (32.9 lb/sq ft)
Power/mass: 0.17 kW/kg (0.10 hp/lb)

Armament

1x nose-mounted machine gun, either 12.7 mm UBS or 7.62 mm ShKAS
up to 200 kg (440 lb) of bombs on two underwing racks

Notes

^ The single-row ASh-21 was essentially half of the two-row, 14-cylinder ASh-82.^[1]

Citations

^ ^a ^b Gunston 1995, p. 469.
^ ^a ^b Gordon Komissarov and Komissarov 2005, p. 249.
^ Gunston and Gordon 1997, p. 97.
^ ^a ^b ^c Gunston and Gordon 1997, p. 99.
^ Gordon Komissarov and Komissarov 2005, pp. 250–251.
^ Gordon Komissarov and Komissarov 2005, p. 251.
^ ^a ^b Gordon Komissarov and Komissarov 2005, p. 250.
^ Thompson 2001, pp. 160–161.
^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Arms transfer database". Stockholm International Peace Research Institute. Retrieved 16 May 2024.
^ Paxton 2016, p. 66.
^ Wragg 2011, p. 63.
^ Wragg 2011, p. 133.
^ Cooper 2017, p. 12.
^ Wragg 2011, p. 158.
^ Wragg 2011, p. 145.
^ Wragg 2011, p. 191.
^ Wragg 2011, p. 196.
^ Wragg 2011, p. 176.
^ Wragg 2011, p. 256.
^ Wragg 2011, p. 273.

References

Cooper, Tom (2017). Hot Skies Over Yemen, Volume 1: Aerial Warfare Over the South Arabian Peninsula, 1962-1994. Solihull, UK: Helion & Company Publishing. ISBN 978-1-912174-23-2.
Gordon, Yefim, Dmitry Komissarov and Sergey Komissarov. OKB Yakovlev: A History of the Design Bureau and its Aircraft. Hinkley, UK: Midland Publishing, 2005. ISBN 1-85780-203-9.
Gunston, Bill. The Osprey Encyclopedia of Russian Aircraft 1975–1995. London, UK: Osprey, 1995. ISBN 1-85532-405-9.
Gunston, Bill and Yefim Gordon. Yakovlev Aircraft since 1924. London, UK: Putnam Aeronautical Books, 1997. ISBN 1-55750-978-6.
Paxton, John, ed. (2016). The Statesman's Year-Book 1981-82. Springer. ISBN 978-0-230-27110-4.
Thompson, Warren. "Twin Mustang in Korea". International Air Power Review. Volume 3, Winter 2001/2002. Norwalk, Connecticut, USA:AIRtime Publishing. ISBN 1-880588-36-6. ISSN 1473-9917. pp. 156–167.
Wragg, David (2011). The World Air Power Guide. Casemate Publishers. ISBN 978-1-84468-784-8.

[3] The single-row ASh-21 was essentially half of the two-row, 14-cylinder ASh-82.^[1]

[GunRus_p469-1] Gunston 1995, p. 469.

[OKBYak_p249-2] Gordon Komissarov and Komissarov 2005, p. 249.

[GunYak_p97-4] Gunston and Gordon 1997, p. 97.

[GunYak_p99-5] Gunston and Gordon 1997, p. 99.

[OKBYak_p250-1-6] Gordon Komissarov and Komissarov 2005, pp. 250–251.

[OKBYak_p251-7] Gordon Komissarov and Komissarov 2005, p. 251.

[OKBYak_p250-8] Gordon Komissarov and Komissarov 2005, p. 250.

[IAPRtwin_p160-1-9] Thompson 2001, pp. 160–161.

[SIPRI-10] ^ ^a ^b ^c ^d ^e ^f ^g ^h ⁱ ^j "Arms transfer database". Stockholm International Peace Research Institute. Retrieved 16 May 2024.

[FOOTNOTEPaxton201666-11] Paxton 2016, p. 66.

[FOOTNOTEWragg201163-12] Wragg 2011, p. 63.

[FOOTNOTEWragg2011133-13] Wragg 2011, p. 133.

[FOOTNOTECooper201712-14] Cooper 2017, p. 12.

[FOOTNOTEWragg2011158-15] Wragg 2011, p. 158.

[FOOTNOTEWragg2011145-16] Wragg 2011, p. 145.

[FOOTNOTEWragg2011191-17] Wragg 2011, p. 191.

[FOOTNOTEWragg2011196-18] Wragg 2011, p. 196.

[FOOTNOTEWragg2011176-19] Wragg 2011, p. 176.

[FOOTNOTEWragg2011256-20] Wragg 2011, p. 256.

[FOOTNOTEWragg2011273-21] Wragg 2011, p. 273.

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