In 1949, the Soviet Union developed an experimental piston-engined trainer known as the Yakovlev Yak-20.
However, this aircraft did not enter production.
The Yakovlev OKB designed the Yak-20 in 1949 as an affordable trainer and sport aircraft for aviation clubs.
The aircraft was intended to be a modern and useful pilot trainer and aerobatic sport aircraft that was considerably cheaper to build and operate than the contemporary Yak-18.
The Yak-20 had a welded steel tube fuselage, skinned with aluminum alloy sheet and fabric, and aluminum alloy wings, skinned in metal back to the single spar, and fabric aft of the spar.
The cockpit had dual stick controls, with the pilot sitting on the left, a central push-pull throttle, and simple gyro instruments.
The engine was the newly developed Ivchenko AI-10 five-cylinder radial, which was small and extremely light, rated at 80 hp, driving a V-515 controllable-pitch counterweight propeller.
Fuel was carried in two 35-litre (7.7-gallon) tanks in the wing roots, ahead of the single spar.
The Yak-20 was structurally similar to the Yak-18 but was designed to be the cheapest modern aircraft that could serve as a useful pilot trainer and aerobatic sport aircraft.
The Yak-20 was initially designed to possess complete aerobatic capabilities and exceptional spin resistance.
The two prototypes underwent testing by pilots Anokhin and Georgii Shiyanov, as well as DOSAAF pilots and a series of renowned aerobatic sport pilots who were invited to fly it.
All expressed their enthusiasm for the aircraft to be put into production.
However, during the State Acceptance trials, the Yak-20 was deemed too small and underpowered by the evaluation team.
They recommended a redesign to match the performance of the Yak-18.
The second prototype, Yak-20-2, addressed some of the criticisms but became heavier and lost the performance edge of the first prototype.
As Yak-18 production was already in full swing, the production of Yak-20 was considered unnecessary.
The final blow came when the production of the small Ivchenko AI-10 engine was cancelled. Variants Yak-20-1 First Prototype. Yak-20-2 Second Prototype Specifications Yak-20-1 Crew 2 Length 7.06 m (23 ft 2 in) Wingspan 9.56 m (31 ft 4 in) Wing area 15 m2 (160 sq ft) Empty weight 470 kg (1,036 lb) Gross weight 700 kg (1,543 lb) Fuel capacity 70 L (18 US gal; 15 imp gal) fuel; 10 kg (22 lb) oil Powerplant 1 × Ivchenko AI-10 5-cylinder air-cooled radial piston engine, 60 kW (80 hp) Propellers 2-bladed V-515 variable-pitch counterweight-type propeller Performance Maximum speed 160 km/h (99 mph, 86 kn) Cruise speed 142 km/h (88 mph, 77 kn) Landing speed 60 km/h (37 mph; 32 kn) Take-off run 70 m (230 ft) Landing run 80 m (260 ft) Range 400 km (250 mi, 220 nmi) Service ceiling 3,000 m (9,800 ft) Time to altitude 1,000 m (3,300 ft) in 9.8 minutes Power/mass 0.085 kW/kg (0.052 hp/lb) Sources Yakovlev Aircraft Since 1924 – Bill Gunston & Yefim Gordon. OKB Yakovlev, A History of the Design Bureau and Its Aircraft—Yefim Gordon, Dmitriy Komissarov & Sergey Komissarov. Soviet Aircrafts Illustrated-A.S.Yakovlev. The History of Soviet Aircraft from 1918-Vaclav Nemecek. Soviet AF Fighter Colours 1941-45-Erik Pilaeskii. Soviet Combat Aircraft of the Second World War, Vol 1, Single Engined Fighters-Yefim Gordon and Dmitri Khazanov. Early Soviet Jet Fighters, The 1940s and early 50s-Yefim Gordon.
