Koolhoven
| Company type | Naamloze vennootschap (public company) |
|---|---|
| Industry | Aircraft manufacturing |
| Predecessor | N.V. Nationale Vliegtuig Industrie (N.V.I.) |
| Founded | 1926 |
| Founder | Frederick "Frits" Koolhoven |
| Defunct | 1956 |
| Fate | Factory destroyed during WWII; company liquidated |
| Headquarters | Rotterdam , Netherlands |
Area served | Netherlands, Europe |
Key people | Frederick "Frits" Koolhoven (chief designer and founder) |
| Products | Aircraft (FK-41, FK-50, FK-58, FK-51, FK-52, and others) |
Number of employees | 1,200 (1938) |
 | This article needs additional citations for verification. (June 2008) |
N.V. Koolhoven was an aircraft producer headquartered in Rotterdam, Netherlands. Established in 1926 and operating until its destruction during the Blitzkrieg in May 1940, it stood as the second most prominent Dutch aircraft manufacturer after Fokker. Despite many of its designs being innovative yet commercially unsuccessful, the company achieved several notable successes, including the FK-58 single-seat monoplane fighter, the FK-50 twin-engine passenger aircraft, and the FK-41, which was produced under license in England by Desoutter.
History
In 1920, aircraft designer Frederick "Frits" Koolhoven returned to his homeland, the Netherlands, after working in England.[1] The post-World War I period had been challenging for him; the British Aerial Transport Company, where he served as chief designer, collapsed, and other manufacturers were struggling to survive and unable to hire new talent. Upon returning to the Netherlands, Koolhoven found that although the national airline KLM was eager to acquire aircraft, the market was overwhelmingly dominated by Fokker. With limited options available, he resumed work in automobile engineering at the Spyker car factory.
In 1921, circumstances improved when a consortium of entrepreneurs founded N.V. Nationale Vliegtuig Industrie ("National Aircraft Industry, Incorporated") and appointed Koolhoven as their chief designer. However, the environment was still not favorable for a second Dutch aircraft company; like BAT before it, N.V.I. developed advanced designs that attracted international attention but failed to secure significant orders. The enterprise lasted only four years.
When N.V.I. dissolved, Koolhoven had gained enough business acumen to persuade some shareholders that the venture could succeed if he assumed full control. Several shareholders agreed, and even as N.V.I. was winding down, its assets were swiftly transferred to a new entity: N.V. Koolhoven vliegtuigen (Koolhoven Aircraft Inc.).
During its initial five years from 1925 to 1930, the company survived by producing custom-built airplanes on demand while gradually expanding into private aviation and attempting to penetrate military markets. Success came in 1930 with the FK-41 high-wing touring monoplane. Although N.V. Koolhoven manufactured only seven FK-41 units itself, this model was licensed for production in England as the Desoutter Mk.I, later upgraded to Mk.II.
By 1933, demand from military clients increased significantly; Koolhoven began producing trainers and reconnaissance aircraft for the Dutch air force along with other nations. As tensions escalated toward war by 1938, orders surged from European air forces competing for every aircraft produced. Even France procured Koolhoven FK-58 fighters due to its own industry’s inability to meet requirements of the Armée de l'Air.
By 1938, Koolhoven’s Waalhaven facility spanned 8,000 square meters and employed approximately 1,200 workers. Although still overshadowed by Fokker, Koolhoven had firmly secured its position as the Netherlands’ second-largest aircraft manufacturer.
The company’s operations came to an abrupt end on 10 May 1940 during the German invasion of the Netherlands. As part of efforts to cripple the Dutch Air Force, Luftwaffe bombers launched a devastating attack on Waalhaven airfield and adjacent facilities early that morning. The assault obliterated the Koolhoven factory within hours along with all drawings, prototypes, and documentation related to its projects. Presently, surviving images of Koolhoven aircraft are limited to newspaper photos and private snapshots.
Frederick Koolhoven passed away from a stroke on 1 July 1946. Although lacking manufacturing capabilities thereafter, his company persisted as a holding entity. Over the following decade various attempts were made to revive production; however, aside from constructing two prototype sailplanes no further developments occurred before N.V. Koolhoven Aeroplanes ceased operations and was liquidated in 1956.
Aircraft
In addition to the 1911 Heidevogel, Koolhoven was responsible for designing 59 aircraft models, sequentially numbered FK-1 through FK-59. Approximately half of these were conceptual designs that never reached production. The initial designs, FK-1 to FK-28, were developed in England for Armstrong Whitworth and BAT, while FK-29 to FK-34 were created for N.V.I.. The remaining projects, FK-35 to FK-59, were produced under Koolhoven's own enterprise. Thus, the FK-35 is considered the first genuine Koolhoven aircraft. However, when establishing N.V. Koolhoven, Frits Koolhoven brought along the design of the FK-30 "Toerist," a light sportsplane initially intended for NVI but never constructed. Consequently, several "Toerist" models manufactured by the new Koolhoven company represent its earliest aircraft, if not chronologically by production date, then at least by their sequence number.
The Koolhoven foundation's website catalogs 26 designs starting with the F.K.30 and continuing from F.K.35 through F.K.59. It also notes that models F.K.37, 38, 39, and 59 were never constructed and provides only images of wooden scale models for F.K.35 and F.K.36. According to Jane's Encyclopedia of Aviation, only the designs F.K.40, 41, 42, 43, 46, 48, 49, 51, 52, 53, and 58 are listed, with mention of an F.K.50-b bomber project not referenced on the foundation’s site.
Among these designs, the most notable include the high-wing monoplane F.K.41, which was produced under license as the Desoutter Mk.II, and the twin-engine transport monoplane F.K.50, two units of which were operated by the Swiss company Template:Interlanguage link multi. In military aviation, the most successful models were the biplane reconnaissance aircraft Koolhoven F.K.51, extensively utilized by the Dutch air force from the mid-1930s until World War II; the biplane scout and fighter Koolhoven F.K.52 employed by the Finnish Air Force; and the single-seat monoplane fighter Koolhoven F.K.58, which was ordered by France and saw action in the Armée de l'Air during the Battle of France.
Below is a comprehensive list summarizing Koolhoven’s aircraft and projects:
- Koolhoven Heidevogel – Early experimental aircraft, one unit built in 1911
- Koolhoven F.K.30 "Toerist" – Light high-wing sports monoplane introduced in 1927
- Koolhoven F.K.35 – Seaplane scout and fighter available as low-wing monoplane or biplane, 1926
- Koolhoven F.K.36 – Enlarged biplane variant of the F.K.35, 1926
- Koolhoven F.K.37 – Design proposal for a three-engine airliner for KLM (not constructed)
- Koolhoven F.K.39 – Various two-seat monoplane fighter design studies (not built)
- Koolhoven F.K.40 – Four or five passenger airliner introduced in 1928
- Koolhoven F.K.41 – High-wing cabin monoplane "sport coupe", licensed production by Desoutter in England
- Koolhoven F.K.42 – High-wing private plane with open cockpit, 1929
- Koolhoven F.K.43 – Three-passenger cabin sportsplane/air taxi similar to the F.K.41, 1930
- Koolhoven F.K.44 "Koolmees" (Great Tit) – Private aircraft resembling the F.K.41/F.K.43 series
- Koolhoven F.K.45 – Biplane designed for aerobatics, 1931
- Koolhoven F.K.46 – Biplane trainer introduced in 1930
- Koolhoven F.K.47 – Biplane serving as private plane/trainer, 1933
- Koolhoven F.K.48 – Six-passenger twin-engine airliner operated by KLM, 1934
- Koolhoven F.K.49 – Twin-engine photo reconnaissance and cartography aircraft developed for Dutch air force in 1935
- Koolhoven F.K.49A – Multi-role aircraft introduced in 1937
- Koolhoven F.K.50 – Eight-passenger twin-engine airliner, enhanced version of the F.K.48 used by Alpair, 1935
- Koolhoven F.K.51 – Military biplane trainer with open cockpit seating, introduced in 1935
- Koolhoven F.K.52 – Two-seat biplane scout/fighter featuring enclosed cabin, 1936
- Koolhoven F.K.53 "Junior" – Low/mid-wing light touring aircraft from 1936
- Koolhoven F.K.54 – High-wing monoplane cabin "Executive plane" with retractable landing gear, 1937
- Koolhoven F.K.55 – Experimental high-performance fighter equipped with contra-rotating propellers, 1936
- Koolhoven F.K.56 – Low-wing two-seat advanced trainer and scout introduced in 1937
- Koolhoven F.K.57 – Twin-engine low-wing executive aircraft from 1938
- Koolhoven F.K.58 – Modern high-performance monoplane fighter developed in 1938
- F.K.59 – Multi-purpose evolution of the F.K.52; construction status unknown; last design by Koolhoven in 1940
- NVI F.K.29 – Two-passenger single-engine biplane; one unit built in 1923
- NVI F.K.31 – Two-seat reconnaissance-fighter; seventeen units built in 1923
- NVI F.K.32 – Two-seat training biplane from 1925
- NVI F.K.33 – Ten-passenger tri-motor airliner; one built for KLM in 1925
- NVI F.K.34 – Three-seat reconnaissance seaplane introduced in 1925
References
- Koolhoven, Dutch aircraft manufacturer overshadowed by Fokker, Theo Wesselink and Thijs Postma, Unieboek B.V., Bussum NL
- Jane's Encyclopedia of Aviation, multiple authors, Portland House, New York, 1980
External links
- Koolhoven Aircraft (Archived version: https://web.archive.org/web/20131016031946/http://members.ziggo.nl/henrikaper/koolhoven/worlds-first-airliner/)
- Alex den Ouden - Historical Technology and Mechanical Engineering (in Dutch)
- ↑ Wragg, David W. (1973). A Dictionary of Aviation (first ed.). Osprey. p. 173. ISBN 9780850451634.