Yakovlev Yak-55

Yak-55
Yak-55 performing low level airshow aerobatics. (Pilot Mark Hensman.)
Role Aerobatic aircraft
National origin Soviet Union
Manufacturer Yakovlev
First flight 28 May 1981




The Yakovlev Yak-55 is a single-seat aerobatic aircraft. Pilots flying the Yak-55 have won several world aerobatic championships.[1]

Development

The Soviet team in the 1976 World Aerobatic Championship, although dominating the championship, finishing first and second in the individual competition and also winning the team and women's competitions in their Yakovlev Yak-50s,[2] were impressed by the performance of competing foreign aircraft which could carry out the required manoeuvers in less space than the Yak-50. A team in the Yakovlev design bureau, led by Sergei Yakovlev, and with V.P. Kondratiev and D.K. Drach as chief engineers, therefore set out to design an all-new dedicated aerobatic aircraft, unrelated to the Yak-50, which would be able to match the tight, low-speed style of Western aircraft.[3][4]

The resulting design, the Yakovlev Yak-55, was a single-engined all-metal cantilever monoplane. The aircraft's wing is mounted midway up the fuselage and is of thick, symmetrical section to aid inverted flight. The pilot sits in an enclosed cockpit under a sliding teardrop canopy level with the trailing edge of the wing and with the seat below wing level. The powerplant is the same tractor configuration 360 horsepower (270 kW) Vedeneyev M14P engine driving a two-bladed V-530TA-D35 propeller, as used by the Yak-50, while the aircraft has a fixed undercarriage with titanium sprung main gear and tailwheel.[3][4]

The prototype Yak-55 first flew in May 1981 and was unveiled at the Moscow Tushino air show in August 1982, and was displayed (but did not compete) at the 1982 World Aerobatic Championships. By this time, fashions in aerobatic flying had changed, with the high energy aerobatics demonstrated by the Yak-50 back in fashion, leading to the Yak-55 being rejected by the Soviet team.[3] The Yak-55 was therefore redesigned with new wings with shorter span, reduced area and a thinner but still symmetrical aerofoil section, giving an increased rate of roll and speed.[4][5][nb 1] Series production finally began in 1985 at Arsenyev,[6] with 108 aircraft being delivered by 1991.[4]

In the late 1980s, work began on a revised version of the Yak-55, the Yak-55M, to meet demands from DOSAAF for an aircraft with further increased rates of roll, and to compete with new designs from the Sukhoi design bureau. The Yak-55M had a still smaller wing, which resulted in the required improvement in roll-rate. It first flew in May 1989, entering production in 1990.[7] 106 Yak-55Ms had been built by the end of 1993, with low rate production continuing.[8]

Operational use

The Soviet aerobatic team first used the aircraft in 1984 when they won the World Aerobatic Championship. That same year the Soviet woman's aerobatic team took first place flying the Yak-55, Kh. Makagonova winning individual gold.[1]

The aircraft has been relatively free of Service Bulletins and Airworthiness Directives and has proved exceedingly effective in competition at all levels. The obvious capabilities of the aircraft and its success in use, together with the relatively large numbers built (some 250) have meant that owners make relatively few modifications and that few are needed.

Variants

Yak-55
Prototype/initial production aerobatic aircraft. Long-span wings.
Yak-55
Revised production version with reduced wingspan and area.
Yak-55M
Further revised version, with revised wings.
Technoavia SP-55M
The SP-55M is a development of the Yak-55M by V.P. Kondratiev, one of the designers of the Yak-55 with a redesigned vertical tail, composite-covered control surfaces, a deeper aft fuselage.[9][10]
Yak-56
The Yak-56 was to be a two-seat trainer based on the Yak-55M, but with a low wing and retractable undercarriage. Power was to have come from a 300 hp VOKBM M-16 eight-cylinder x-8 engine driving an AV-16 three-bladed propeller. The prototype was expected to fly in 1992, but delays in producing the engine meant that Yakovlev decided to produce the Yak-54 instead.[11][12]

Operators

 Lithuania

Specifications (Yak-55M)

Data from Brassey's World Aircraft & Systems Directory 1999/2000 [13]

General characteristics

Performance

See also

Related development
Aircraft of comparable role, configuration and era

References

Wikimedia Commons has media related to Yakovlev Yak-55.
  1. ↑ Gunston blames the redesign on the need to deal with structural failures of the original wing.[4]
  1. 1 2 Gunston, 1997
  2. ↑ Smith Flight International 21 August 1976, pp. 437–439.
  3. 1 2 3 Gordon, Komissarov and Komissarov 2005, p. 290.
  4. 1 2 3 4 5 Gunston and Gordon 1997, p. 209.
  5. ↑ Gordon, Komissarov and Komissarov 2005, pp. 290–291.
  6. ↑ Gordon, Komissarov and Komissarov 2005, p. 291.
  7. ↑ Gordon, Komissarov and Komissarov 2005, pp. 291–292.
  8. ↑ Gunston and Gordon 1998, pp. 209–210.
  9. ↑ Gordon, Komissarov and Komissarov 2005, p.292.
  10. ↑ Jackson 2003, p. 424.
  11. ↑ Gunston and Gordon 2005, p. 210.
  12. ↑ Gordon, Komissarov and Komissarov 2005, pp. 294–295.
  13. ↑ Taylor 1999, pp. 486–487.
  14. ↑ 105 km/h (57 knots, 66 mph) inverted
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