Editing Yakovlev Yak-11 (section)

==Design and development==
The [[Yakovlev|Yakovlev design bureau]] began work on an advanced trainer based on the [[Yakovlev Yak-3|Yak-3]] fighter in mid-1944, although the trainer was of low priority owing to the ongoing [[Second World War]].<ref name="GunRus p469">Gunston 1995, p. 469.</ref> The first prototype of the new trainer, designated Yak-UTI or Yak-3UTI flew in late 1945. It was based on the [[radial engine|radial]]-powered Yak-3U, but with the new [[Shvetsov ASh-21]] seven-cylinder radial replacing the [[Shvetsov ASh-82|ASh-82]] of the Yak-3U.<ref name="OKBYak p249">Gordon Komissarov and Komissarov 2005, p. 249.</ref>{{#tag:ref|The single-row ASh-21 was essentially half of the two-row, 14-cylinder ASh-82.<ref name="GunRus p469"/>|group=nb}} 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 [[synchronization gear|synchronised]] [[Berezin UB|UBS]] 12.7&nbsp;mm machine gun and wing racks for two 100&nbsp;kg (220&nbsp;lb) bombs comprised the aircraft's armament.<ref name="GunYak p97">Gunston and Gordon 1997, p. 97.</ref>

[[File:LET C-11 ‘1706’ (33733903654).jpg|left|thumb|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.<ref name="OKBYak p249"/> This aircraft passed state testing in October 1946, with production beginning at factories in [[Saratov]] and [[Leningrad]] in 1947.<ref name="GunYak p99">Gunston and Gordon 1997, p. 99.</ref>

Production Yak-11s were heavier than the prototypes, with later batches fitted with non-retractable tailwheels and revised propellers. A 7.62&nbsp;mm [[ShKAS machine gun]] was sometimes fitted instead of the UBS, while some were fitted with rear-view periscopes above the windscreen.<ref name="GunYak p99"/> Soviet production totalled 3,859 aircraft between 1947 and 1955, with a further  707 licence-built by [[Let Kunovice|Let]] in [[Czechoslovakia]] as the C-11.<ref name="OKBYak p250-1">Gordon Komissarov and Komissarov 2005, pp. 250–251.</ref>

=== 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.<ref name="OKBYak p251">Gordon Komissarov and Komissarov 2005, p. 251.</ref>