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Fokker D.XXIII

Twin-Engine, Single-Seat Fighter Prototype Aircraft

Just one D.XXIII flying prototype was completed by Fokker prior to the German invasion of May 1940.
Authored By: Staff Writer | Edited: 5/15/2018
National Flag Graphic


Year: 1939
Status: Cancelled
Manufacturer(s): Fokker - Netherlands
Production: 1
Capabilities: Fighter; X-Plane;
Crew: 1
Length: 33.46 ft (10.2 m)
Width: 37.73 ft (11.5 m)
Height: 12.47 ft (3.8 m)
Weight (Empty): 4,806 lb (2,180 kg)
Weight (MTOW): 6,504 lb (2,950 kg)
Power: 2 x Walter Sagitta I-SR air-cooled radial piston engines developing 530 horsepower each and driving three-bladed propeller units.
Speed: 326 mph (525 kph; 283 kts)
Ceiling: 29,528 feet (9,000 m; 5.59 miles)
Range: 522 miles (840 km; 454 nm)
Operators: Netherlands (cancelled)
One of the inherent issues of flying single-engined, propeller-driven fighter-type aircraft of the 1930s was the natural "pull" of the airframe to one side or the other due to torque (caused by the spinning motion of the propeller blades). The pilot was typically forced to manually compensate for this and only the addition of a second engine to help offset this pulling action was found as the best solution. In The Netherlands, just prior to World War 2 (1939-1945), Marius Beeling was at work on a new type of single-seat, twin-engine fighter design which attempted to remedy this issue in a different way - by having both engines seated in tandem along the fuselage, one arranged to "pull" the aircraft through the skies and the other arranged to "push" it.

The resulting aircraft was the Fokker D.XXIII which flew for the first time in prototype form on May 30th, 1939. Its general shape involved a center-set fuselage "pod" containing both engines as well as the cockpit and avionics. To this was added a wing mainplane fitted under the fuselage and extending out straight with rounded wingtips. From each wing leading edge originated tail booms which extended to the rear of the aircraft. These appendages were then joined by a shared horizontal stabilizer and this horizontal plane was straddled at either end by small-area, rounded vertical fins. A rather modern tricycle undercarriage, fully retractable, was fitted for ground running.

As tested, the aircraft was powered through 2 x Walter Sagitta I-SR 12-cylinder air-cooled piston engines developing 530 horsepower each and driving three-bladed propeller units fore and aft of the fuselage. Listed specs included a maximum speed of 326 miles per hour, a range out to 522 miles and a service ceiling of 30,000 feet.

Proposed armament became 2 x 13.2mm heavy machine guns and 2 x 7.9mm medium machine guns.

Of seemingly sound design, good overall performance and generally well-armed for its time, the D.XXIII was a promising single-seat fighter heading into the wartime period.

To move the test phase along the prototype was completed with thick wooden wing mainplanes whereas the production-quality fighter was to feature all-metal construction. Tested indicated overheating issues with the rear-mounted air-cooled engine which was natural given its placement within the fuselage (and lack of direct air flow). Only about four hours of testing were had on this Dutch fighter prototype before the German invasion of May 1940 ended all hope for its contribution in the defense of The Netherlands. The program was not resurrected during the war nor in the post-war period leaving the D.XXIII as nothing more than a footnote in World War 2 aviation.


2 x 13.2mm heavy machine guns
2 x 7.9mm medium machine guns

Graphical image of an aircraft medium machine gun
Graphical image of an aircraft heavy machine gun

Variants / Models

• D.XXIII - Base Series Designation; single prototype completed.
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