Yakovlev Yak - 11 The Yakovlev Yak - 11 ( NATO reporting name : " Moose " , ) was a trainer aircraft used by the Soviet Air Force and other Soviet - influenced air forces from 1947 until 1962 . History . The Yakovlev design bureau began work on an advanced trainer based on the successful Yak - 3 fighter in mid 1944 , although the trainer was of low priority owing to the ongoing Second World War . 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 . It used the same all - metal wings as the Yak - 3U , with a fuselage of mixed metal and wood construction . 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 . An improved prototype flew in 1946 , with revised cockpits and a modified engine installation with the engine mounted on shock absorbing mounts . This aircraft successfully passed state testing in October 1946 , with production beginning at factories in Saratov and Leningrad in 1947 . Production Yak - 11s were heavier than the prototypes , with later batches fitted with non - retractable tail wheels 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 . In total , Soviet production amounted to 3 , 859 aircraft between 1947 and 1955 . with a further 707 licence - built by Let in Czechoslovakia as the C - 11 . The Yak - 11 set five world - class records . 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 similar equipment 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 examples were built in Czechoslovakia as the C - 11U . Operational history . The Yak - 11 entered service in 1947 , serving as a standard advanced trainer with the Soviet Air Forces and DOSAAF . Both 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 . 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 shot down by a North American F - 82 Twin Mustang over Kimpo Airfield on 27 June 1950 . East Germany used the Yak - 11 to intercept American reconnaissance balloons . Survivors . Due to its Yak - 3 lineage , the Yak - 11 has recently seen widespread popularity among warbird enthusiasts . Souped - up versions of the Yak - 11 can be frequently seen at air race s . About 120 Yak - 11s remain in airworthy condition . Description . Mixed construction ( metal and wood ) trainer plane . 7 - cylinder radial engine with two - blade fixed propeller . Conventional retractable landing gear with fixed tailwheel .