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.
Design and development
Juhani Heinonen, an aeronautical engineer who had previously worked for the
Valmet
Valmet Oyj is a Finnish company and a developer and supplier of technologies, automation systems and services for the pulp (paper), pulp, paper and energy industry, energy industries.
Valmet has over 200 years of history as an industrial oper ...
aircraft factory at
Tampere
Tampere ( , , ; sv, Tammerfors, ) is a city in the Pirkanmaa region, located in the western part of Finland. Tampere is the most populous inland city in the Nordic countries. It has a population of 244,029; the urban area has a population o ...
, and then for
Finnair
Finnair ( fi, Finnair Oyj, sv, Finnair Abp) is the flag carrier and largest airline of Finland, with its headquarters in Vantaa on the grounds of Helsinki Airport, its hub. Finnair and its subsidiaries dominate both domestic and internationa ...
, designed a single-seat, single engined aerobatic sport aircraft, the Heinonen HK-1. It was a
low winged monoplane
A monoplane is a fixed-wing aircraft configuration with a single mainplane, in contrast to a biplane or other types of multiplanes, which have multiple planes.
A monoplane has inherently the highest efficiency and lowest drag of any wing confi ...
of all-wooden construction, powered by a
Walter Mikron
The Walter Mikron is a four-cylinder, air-cooled, inverted straight engine for aircraft.
Development
Developed in Czechoslovakia in the early 1930s, the engine saw limited use in late 1930s and early 1950s. In the 1980s an initial batch of eng ...
air-cooled inline engine rated at driving a two-bladed propeller.
Split flaps were fitted to the wings, while the aircraft had a fixed
tailwheel undercarriage
Conventional landing gear, or tailwheel-type landing gear, is an aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air. It counters the force of gravity by using either static lift or by using the dynami ...
, with a steerable tailwheel but no brakes. The pilot sat under a sliding
perspex
Poly(methyl methacrylate) (PMMA) belongs to a group of materials called engineering plastics. It is a transparent thermoplastic. PMMA is also known as acrylic, acrylic glass, as well as by the trade names and brands Crylux, Plexiglas, Acrylite ...
canopy.
[Best-Devereux ''Flight'' 17 January 1958, p. 85.] 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
Leidschenveen-Ypenburg () is a Vinex-location and district of The Hague, located in the southeast. It is geographically connected to the main body of the city by only a narrow corridor. It consists of four quarters: Hoornwijk and Ypenburg on the ...
airshows. On 10 July 1957, Heinonen flew the HK-1, fitted with an additional ventral fuel tank,
non-stop between
Madrid
Madrid ( , ) is the capital and most populous city of Spain. The city has almost 3.4 million inhabitants and a metropolitan area population of approximately 6.7 million. It is the second-largest city in the European Union (EU), and ...
, Spain and
Turku
Turku ( ; ; sv, Åbo, ) is a city and former capital on the southwest coast of Finland at the mouth of the Aura River, in the region of Finland Proper (''Varsinais-Suomi'') and the former Turku and Pori Province (''Turun ja Porin lääni''; ...
in Finland, covering a distance of in 17 hours 1 minute, setting a class world distance record for aircraft of less than take-off weight.
[Taylor 1962, p. 30.] For this flight, Heinonen was awarded a
Louis Blériot medal by the ''
Fédération Aéronautique Internationale
The (; FAI; en, World Air Sports Federation) is the world governing body for air sports, and also stewards definitions regarding human spaceflight. It was founded on 14 October 1905, and is headquartered in Lausanne, Switzerland. It maintai ...
''. This record was not broken until 2 July 1975.
The aircraft is now preserved at the
Finnish Aviation Museum
The Finnish Aviation Museum ( fi, Suomen ilmailumuseo, sv, Finlands flygmuseum) is a museum specialising in aircraft, located near Helsinki Airport in Veromies, Vantaa, Finland.
History
The Aviation Museum Society ( fi, Ilmailumuseoyhdistys ry) ...
near Helsinki Airport.
Specifications
See also
Notes
References
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{{refend
1950s Finnish sport aircraft
Low-wing aircraft
Single-engined tractor aircraft
Aircraft first flown in 1954
Conventional landing gear