Yakovlev Yak-23

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The Yakovlev Yak-23 (in Russian Як-23, NATO designation Flora) was a jet fighter developed in the USSR in the 1940s, used in early 1950s.

Yak-23 in Muzeum Orla Bialego in Poland

[edit] History

The Yak-23 was developed as a simple lightweight jet fighter, on Yakovlev's own initiative. It was a development of earlier Yak-15 and Yak-17 fighters, retaining their non-conventional layout with a jet engine in the fuselage nose and exhaust under the cockpit, but the construction was all new. Wings were derived from Yak-19. The Yak-23 used a Soviet copy of the British Rolls-Royce Derwent V turbojet engine, produced as the Klimov RD-500. It first flew on July 8, 1947. After successful flights, it underwent state trials in 1948 and was accepted for series production. It was evaluated as highly maneuverable, with a good acceleration and take-off and climb capabilities thanks to high thrust-to-weight ratio. Faults were poor directional stability at speeds around Mach 0.86 and lack of cockpit pressurization. Despite being one of the best straight-wing jet fighters, it was inferior to new swept-wing designs.

The first aircraft were produced in a factory in Tbilisi in October 1949. In late 1949 they entered Soviet air force service, and were also ordered for export in 1949-50. The Yak-23 was quickly replaced in the Soviet service with more complicated swept-wing MiG-15, which offered superior performance. In total, only 310 Yak-23 aircraft were built before production ended in 1950. Apart from the fighter, the Yak-23UTI two-seat trainer was developed, with an instructor's cockpit extended towards nose. Sources differ, whether it was produced at all, in a small series at best.

Small numbers of Yak-23 were exported to Czechoslovakia (20 from 1949, named S-101), Bulgaria (from 1949), Poland (about 100, from 1950), Romania (40, from 1951), probably Hungary and Albania. Poland and Czechoslovakia acquired licence of Yak-23, but didn't start production in favour of the MiG-15. Yak-23s were withdrawn by the late 1950s. They were not used in combat (there are reports of US pilots encountering Yak-23s during the Korean War, but their presence in North Korea is not confirmed).

[edit] U.S. testing

A single Yak-23 was acquired by US intelligence, probably via Yugoslavia, in November, 1953. The aircraft arrived disassembled, and was shipped to the Air Force Test and Evaluation Center at Wright Field near Dayton, Ohio. It was reassembled and made operational for several flight tests, during which time it was disguised with U.S. markings. Efforts were made to keep the aircraft's identity secret, and it was only flown in the early morning. On one occasion it was passed on the runway by a formation of F-86's, whose pilots inquired as to the plane's identity. A story was conceived that the aircraft was a Bell X-5, who's design was similar. At the completion of design and flight evaluations the aircraft was again disassembled and shipped quietly back to Yugoslavia in its original paint scheme.

[edit] Records

On September 21, 1956, the Polish pilot Andrzej Abłamowicz set two FAI world records on Yak-23 with civilian markings SP-GLK, in its weight class, climbing at 3000 m in 119 seconds and at 6000 m in 197 seconds. This plane was withdrawn in 1961, being possibly the last Yak-23 used in the world.