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Koolhoven F.K.55

Single-Seat, Single-Engine Prototype Fighter Aircraft

Koolhoven F.K.55

Single-Seat, Single-Engine Prototype Fighter Aircraft

OVERVIEW
SPECIFICATIONS
ARMAMENT
VARIANTS
HISTORY
MEDIA
OVERVIEW



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.
National Flag Graphic
ORIGIN: Netherlands
YEAR: 1938
STATUS: Cancelled
MANUFACTURER(S): Koolhoven - Netherlands
PRODUCTION: 1
OPERATORS: Netherlands (cancelled)
SPECIFICATIONS



Unless otherwise noted the presented statistics below pertain to the Koolhoven F.K.55 model. Common measurements, and their respective conversions, are shown when possible.
CREW: 1
LENGTH: 30.35 feet (9.25 meters)
WIDTH: 31.50 feet (9.6 meters)
HEIGHT: 8.53 feet (2.6 meters)
WEIGHT (EMPTY): 3,527 pounds (1,600 kilograms)
WEIGHT (MTOW): 4,850 pounds (2,200 kilograms)
ENGINE: 1 x Lorraine Petrel 12Hrs 12-cylinder Vee engine developing 860 horsepower.
SPEED (MAX): 317 miles-per-hour (510 kilometers-per-hour; 275 knots)
RANGE: 528 miles (850 kilometers; 459 nautical miles)
RATE-OF-CLIMB: 2,580 feet-per-minute (786 meters-per-minute)




ARMAMENT



PROPOSED:
1 x 20mm cannon firing through propeller hub
4 x 7.7mm (0.303) machine guns in wings
VARIANTS



Series Model Variants
• F.K.55 - Base Series Designation; single prototype completed in 1938.


HISTORY



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.
Prior to World War 2 (1939-1945) the Dutch held a respectable aero industry that produced a few notable types of local design. The Koolhoven F.K.55 was a prototype developed along the lines of a high-speed fighter and appeared during the latter half of the 1930s. The line ended with a sole example being built, its first flight held on June 30th, 1938, and the program terminated before the end of the year.

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.




MEDIA









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.

Image of collection of graph types

Relative Maximum Speed Rating
Hi: 400mph
Lo: 200mph
    This entry's maximum listed speed (317mph).

    Graph average of 300 miles-per-hour.
City-to-City Ranges
NYC
 
  LDN
LDN
 
  PAR
PAR
 
  BER
BER
 
  MSK
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  TKY
TKY
 
  SYD
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  LAX
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  NYC
Graph showcases the Koolhoven F.K.55's operational range (on internal fuel) when compared to distances between major cities.
Aviation Era
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Useful in showcasing the era cross-over of particular aircraft/aerospace designs.
Unit Production Comparison
Comm. Market HI*: 44,000 units
Military Market HI**: 36,183 units
1
1

  * Commercial Market High belongs to Cessna 172.

  ** Military Market High belongs to Ilyushin Il-2.


Supported Roles
A2A
Interception
UAV
Ground Attack
CAS
Training
ASW
Anti-Ship
AEW
MEDEVAC
EW
Maritime/Navy
SAR
Aerial Tanker
Utility/Transport
VIP
Passenger
Business
Recon
SPECOPS
X-Plane/Development
A2A=Air-to-Air; UAV=Unmanned; CAS=Close Support; ASW=Anti-Submarine; AEW=Airborne Early Warning; MEDEVAC=Medical Evac; EW=Electronic Warfare; SAR=Search-Rescue
In the Cockpit...