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Only one example of the Dutch Koolhoven F.K.55 fighter was ever completed before the program was cancelled in full prior to World War 2.
Detailing the development and operational history of the Koolhoven F.K.55 Single-Seat, Single-Engine Prototype Fighter Aircraft. Entry last updated on 5/10/2018. Authored by Staff Writer. Content ©www.MilitaryFactory.com
Its design, begun in 1937, was one of a sleek all-modern fighter with the cockpit set forward of the wing mainplanes and the mainplanes shifted just ahead of midships (and shoulder-mounted). Wingtips were rounded and the appendages straight in appearance. The tail unit was conventional with a single fin and a pair of horizontal planes. Construction was mixed, composed of metal and wood. A "tail dragger" undercarriage was featured. The engine of choice became a Lorraine 12Hrs "Petrel" V-12 of 860 horsepower driving a pair of two-bladed propeller assemblies at the nose in contra-rotating fashion. Due to the placement of the cockpit, well forward in the fuselage, the engine was installed aft of the pilot (as in the famous Bell P-39 "AiraCobra" fighter detailed elsewhere on this site).
The completed aircraft was made ready for its first flight in the early part of 1938 and has all of the appearance required of a high-performance aircraft. A fixed undercarriage greeted this monumental moment for the design with the intention that a retractable system be instituted later in development. However, in practice, the design proved lacking in the power necessary for the role - the 860 horsepower produced for the engine was just take-off power. Underpowered and costly to revise, this aircraft endeavor was eventually abandoned by Koolhoven and fell to the pages of military aviation history. Engineers pushed for the installation of a Lorraine "Sterna" supercharged engine of 1,200 horsepower to no avail.
As designed, the F.K.55 sported an maximum speed of 317 miles per hour, a cruising speed nearing 280 miles per hour, a range out to 530 miles and a rate-of-climb of 2,580 feet-per-minute (all figures estimated by Koolhoven). Its proposed armament scheme was to fit a 20mm cannon firing through the propeller hub and 4 x .303 machines guns, two installed in each wing. The P-39 fielded similar armament though a more potent 37mm autocannon in the nose. Its performance was much better as well: a maximum speed of 375 mph was seen in the Q-models. Like the F.K.55, it first flew in 1938 and went on to have a strong war record in the subsequent global conflict.
Any available statistics for the Koolhoven F.K.55 Single-Seat, Single-Engine Prototype Fighter Aircraft are showcased in the areas immediately below. Categories include basic specifications covering country-of-origin, operational status, manufacture(s) and total quantitative production. Other qualities showcased are related to structural values (namely dimensions), installed power and standard day performance figures, installed or proposed armament and mission equipment (if any), global users (from A-to-Z) and series model variants (if any).
Our Data Modules allow for quick visual reference when comparing a single entry against contemporary designs. Areas covered include general ratings, speed assessments, and relative ranges based on distances between major cities.
Relative Maximum Speed Rating
This entry's maximum listed speed (317mph).
Graph average of 300 miles-per-hour.
Graph showcases the Koolhoven F.K.55's operational range (on internal fuel) when compared to distances between major cities.