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Typenumber M.9./K.1.
Type of aircraft
Twin-engined fighter
Date first flight 1915
Crew 3
Enginetype 2 x Oberursel U O
2 * 80 hp
armament 2 x machine gun
Fokker M.9./K.1.

Fokker M.9

Fokker M.9 with transportfacility

First twin-engine plane

The Fokker M.9./K.1. (K= Kampfflugzeug) was a biplane with twin tail booms.
It was the results of the German military encouraging aircraft firms to fit a machine gun to the observer's cockpit of their two seat types. Such armament was purely defensive; what was need was an offensive fighter aircraft.

With this in mind, Anthony Fokker decided to build such an aircraft without official guidance or advice. He confidently expected to achieve quick results by using components of existing types.


Two M.7 fuselage structures, engineless but each with its individual standard tail group, were joined by a biplane structure.

Between these fueselages a nacelle was mounted centrally on the lower wing. In this the pilot sat, sandwiched between two 80 hp Oberursel rotaries, one driving a tractor airscrew, the other a pusher. Outboard of the fuselages the equal span wings had two bay bracing. Two gunners were to be carried, one in the front of each fuselage; no armament was ever fitted, however, and there was no provision for rearward defence.

First take-off

For the first take off, six men were posted along the intended run armed with fire extinguishers; others sat in two motor cars and on motorcycles with engines running, ready to rescue the pilot in the event of mishap. The take off run was rather long. On landing, Fokker complained that the fuselages moved when the wings were warped. He made another flight alone, and finally took up two passengers (military mechanics) in the gunners' positions in an attempt to correct the M.9's tail heaviness. These flights took place within the space of a few days and were quite short.


The combination of wing warping control and twin, unconnected tail booms resulted in some undesirable handling characteristics.

After this perfunctory testing of a radical new design Fokker gave up. The M.9 was put aside for dismantling, and its development was completely abandoned. Any aeronautical engineer could have forseen that the lack of any rear connection between the fuselages would poermit flexing and leand to unsatisfactory control. If Fokker had had more patience he might have made something of the M.9.