Top speed 215 km/h First flight August 1954 | Length 5.35 m Designer Juhani Heinonen | |
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The Heinonen HK-1 Keltiäinen is a Finnish single-seat, single-engined sport aircraft of the 1950s. Only a single example was built, which was used by its designer to set a class distance record in 1957 that stood for 18 years before being beaten.
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Design and development
Juhani Heinonen, an aeronautical engineer who had previously worked for the Valmet aircraft factory at Tampere, and then for Finnair, designed a single-seat, single engined aerobatic sport aircraft, the Heinonen HK-1. It was a low winged monoplane of all-wooden construction, powered by a Walter Mikron air-cooled inline engine rated at 48 kilowatts (65 hp) driving a two-bladed propeller. Split flaps were fitted to the wings, while the aircraft had a fixed tailwheel undercarriage, with a steerable tailwheel but no brakes. The pilot sat under a sliding perspex canopy. A prototype was built at the glider school at Jämi, first flying in August 1954.
Operational history
The HK-1 was displayed at the 1955 and 1957 Ypenburg airshows. On 10 July 1957, Heinonen flew the HK-1, fitted with an additional ventral fuel tank, non-stop between Madrid, Spain and Turku in Finland, covering a distance of 2,844 kilometres (1,767 mi) in 17 hours 1 minute, setting a class world distance record for aircraft of less than 500 kilograms (1,100 lb) take-off weight. For this flight, Heinonen was awarded a Louis Blériot medal by the Fédération Aéronautique Internationale. This record was not broken until 2 July 1975.
The aircraft is now preserved at the Finnish Aviation Museum near Helsinki Airport.
Specifications
Data from Jane's All The World's Aircraft 1956–57
General characteristics
Performance