Fokker D.XXIII – A Promising Twin-Engine Fighter Prototype

In late 1937, work began on the D.XXIII, a single-seat, twin-engine fighter by the Dutch company ‘Fokker’.

The unique design of the plane was a result of trying to overcome an issue that plagued single-engine planes of the time – as the propeller spins, the torque created pulls the plane to one side, which the pilot is then forced to fight against.

The designer Marius Beeling proposed to remedy this by mounting two engines to a planes fuselage, one at the front to pull the aircraft, and one at the back to push the aircraft.


Design of the D.XXIII

The result of Marius Beeling’s work was the Fokker D.XXIII. It featured a central fuselage which contained the cockpit and both engines. It had a twin boom design which were connected by a rear horizontal stabiliser.

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The D.XXIII was powered by two Walter Sagitta air-cooled V-12 engines which each produced 530 horsepower.

The D.XXIII on show in Paris in 1939.
The D.XXIII on show in Paris in 1939.

The D.XXIII had a length of 10.2 meters, or 33 feet 6 inches. Its wingspan measured 11.5 meters, equivalent to 37 feet 9 inches. In terms of height, the aircraft stood at 3.8 meters, or 12 feet 6 inches tall. Furthermore, it had a maximum takeoff weight of 2,950 kilograms, which translates to 6,504 pounds.

Although not fitted to the prototype, the finished fighter was proposed to have two 13.2 mm machine guns, and two 7.9 mm machine guns.

First Flight

The prototype took flight on 30 May, 1939. Testing indicated cooling problems on the rear engine due to a lack of direct airflow. Suggestions were made to fit Daimler-Benz or Rolls-Royce engines to overcome this.

The prototype Fokker D.XXIII on the runway in 1939.
The prototype Fokker D.XXIII on the runway in 1939.

The placement of the rear engine also caused worry if the pilot needed to bail out, that he might not be able to clear the propeller. Modifications were made to the prototype to overcome this, but for the production aircraft, there were proposals for an ejection seat.

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The performance statistics of the aircraft are estimated to have a top speed of 326 mph, a range of 520 miles and a service ceiling of 30,000 feet.

The D.XXIII prototype in flight, 1939.
The D.XXIII prototype in flight, 1939.

Fate of the D.XXIII

The D.XXIII was flown for roughly around four hours and although the testing of the aircraft looked promising, the project had to be ceased after Germany invaded in May, 1940.

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What happened to the prototype is unclear, but there are records showing it was damaged during a test flight just one month before the invasion by German forces.