Engineering:Harakka

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Harakka
H-56 Harakka II (Helsinki Museum 2001-09-15).JPG
Harakka II glider at Suomen Ilmailumuseo (Finnish Aviation Museum), 2001
Role Primary glider
National origin Finland
First flight February 1945

The Harakka ("European magpie") was a primary glider produced for pilot training in Finland in the 1940s. Its design was typical of this class of aircraft, a "keel" with a pilot's seat suspended beneath a high, strut-braced monoplane wing, and carrying a conventional empennage at the end of an open framework.[1] First flown in February 1945, the type was built from plans by Finnish gliding clubs and soon replaced earlier primary gliders such as the Grunau 9,[2] becoming a standard piece of equipment in the clubs.[1][3]

In 1946, Raimo Häkkinen and Juhani Heinonen from Polyteknikkojen Ilmailukerho redesigned the Harakka to strengthen it.[4] This improved version became known as the Harakka II or PIK-7.[4][5][6] In 1948, a single example of a more radically redesigned version designated Harakka III flew.[7] This had the framework that supported the tail replaced by a single boom.[7]

Examples of the Harakka I and Harakka II are preserved at the Suomen ilmailumuseo[8] and the Karhulan ilmailukerho Aviation Museum,[1][6] with the sole Harakka III also preserved at the latter museum.[7]


Variants

  • Harakka I - initial version
  • Harakka II - strengthened version (several dozen built)[4]
  • Harakka III - version with redesigned tail (1 built)[7]


Specifications (Harakka II)

Data from "Harakka II (H-57)"

General characteristics

  • Crew: One pilot
  • Length: 5.72 m (18 ft 9 in)
  • Wingspan: 10.60 m (34 ft 9 in)
  • Height: 1.30 m (4 ft 3 in)
  • Wing area: 15 m2 (161 sq ft)
  • Empty weight: 92 kg (200 lb)
  • Gross weight: 200 kg (440 lb)

Performance

  • Maximum speed: 117 km/h (73 mph, 63 kn)
  • Maximum glide ratio: 10.5:1
  • Rate of sink: 1.2 m/s (236 ft/min)

Notes

  1. 1.0 1.1 1.2 "Harakka I (H-12)"
  2. "Grunau 9 ja PIK-7 Harakka, kerhon 1940-50-lukujen alkeiskoulukoneet"
  3. Hardy 1982, p.74
  4. 4.0 4.1 4.2 "PIK-sarjan lentokoneet"
  5. Taylor 1989, p.726
  6. 6.0 6.1 "Harakka II (H-57)"
  7. 7.0 7.1 7.2 7.3 "Harakka III/PIK-7 (H-34)"
  8. "Aircraft on display" [sic]

References