Yak-23 (NATO designation “Flora”) was the last of Alexander Yakovlev’s single-engined fighters.
At the end of WWII and shortly afterwards Russians hectically looked for ways to catch up with the world’s latest jet designs. Engines captured from Germans or purchased from the British were copied, re-designated and mounted on prototypes.
Yak-15 was based on the airframe of the Yakovlev’s aerodynamically most perfected piston-engined fighter – the Yak-3. The new design retained its predecessor’s wings, rear fuselage, and tail unit. It was powered by a copy of the German axial-flow Junkers Jumo 004B turbojet engine, designated RD-10. The tail wheel was replaced by a metal roll, whilst the bottom of the fuselage was protected from the exhaust nozzle by a metal screen. After successful tests Yak-15 was accepted for series production, whereas engineers worked on its future successors.
Yak-17, developed from the Yak-15, featured tricycle landing gear arrangement, new wings and empennage. Although mass-produced, it was treated as a stop-gap solution and soon phased out in favour of Yak-23.
The production of the new type commenced in 1948 and in 1950 first aircraft were delivered to the Polish Air Force. Compared to piston-engine aircraft, Yak-23 was a revolutionary design. It was much faster and more manoeuvrable than its predecessors, and despite its barrel-like shapes, dictated by its RD-500 engine (a Soviet copy of the British Rolls-Royce Derwent turbojet engine), it was aerodynamically refined and elegant-looking. As a matter of fact, this elegance came at a cost which proved to be the design’s paramount flaw. Yak-23’s engine was mounted at an angle and when throttled up, it made the aircraft rear up, which was totally unacceptable in combat, when precision of manoeuvre was indispensable. There were, however, some advantages which partially counterbalanced this flaw. Apart from its excellent manoeuvrability, Yak-23 featured high thrust-to-weight ratio, which gave him the unmatched climb rate of 47 metres per second, far better than in later MiG-15s.
The type was also equipped, for the first time in Soviet aircraft, with an ejection seat, fired by means of an explosive cartridge. The two-spar trapezoidal wing with 3,5° dihedral was manufactured as one piece. The aircraft’s wingtips were equipped with shackles for mounting auxiliary fuel tanks or 60 kg bombs.
The front section of the fuselage was removable for easier access to the powerplant, the middle section housed cockpit, and the aft part – fuselage fuel cells and radio equipment. Yak-23 was at that time the lightest fighter in its class, and duly considered one of the best straight-wing design of its times. It was exported to several former Eastern-block countries and flown in combat by volunteers during the Vietnam War. The type was scheduled to licensed production in Poland and Czechoslovakia, but the advent of the swept-wing era made those plans obsolete…