De Fokker D.XII

The Netherlands

The history of this type begins with the D.XI that was designed for America. The order for this was received in August 1922. The aircraft had to be equipped with a Curtiss D-12 engine. Only after much experimentation a suitable aircraft was created. Then it was decided to actually build the three PW-7s (Pursuit Watercooled) ordered by America. That was at the end of May 1923. The type deviated from the D.XI production and was designated as D.XII. In August 1923 the first aircraft was ready. But with a Curtiss D-12 engine that did not yet run perfectly. And tested with different propellers. The wing arrangement and the tail were also still being tinkered with. The Army Air Service had little confidence in it because of all the delays. They had also already given Curtiss a production order for the PW-8. That is why they first sent a pilot to the Netherlands for a test. As a result, the shipment of the first two D.XIIs did not take place until mid-December 1923.

Due to the preference of the Army Air Service, the second aircraft had wings covered with cloth. These were less stiff than the plywood-covered wings that Fokker wanted. This also meant that instead of the V-style between the upper and lower wing, an N-style was needed for the second aircraft. For the third aircraft, the choice of the wing covering was left to the Air Service. This choice was only made after the first two aircraft had been tested. As a result, the third aircraft did not ship to America until the end of 1924. By then, a production order had also been placed for the Boeing PW-9. For Fokker, the chances of that happening were gone.

America

The supplied propellers on the first PW-7, which was given McCook Field number P326, were inadequate. A Curtiss propeller was fitted instead. Good results were achieved with this by the end of January 1924. However, the lack of strength calculations raised doubts about the aircraft. These were further increased when flutter of the upper wing was found during 'service tests' at Selfridge Field. This was solved by removing the balance section of the ailerons. On 30 June 1924, the aircraft rolled over during a landing in a cornfield near Mt Clemens. The fuselage suffered considerable damage. The aircraft was eventually written off in October 1924.

The second aircraft, AS 68581, was given McCook Field number P327. After fitting the engine it first flew in February 1924. Damage to the tail skid soon occurred. It was then decided to test the aircraft statically for strength. Finally it was scrapped in February 1925.

The third aircraft with registration AS 68582 was ready in early 1924. However, at the request of the Air Service, further changes were required. This resulted in waiting until September for changes. Finally, the aircraft with the D-12 engine (which Fokker had borrowed) was shipped at the end of 1924. In America, the aircraft was given McCook Field number P378 and became XPW-7. It became known after testing by Lt Doolittle. However, when it was written off in early 1928, the total flight time was only

246 hours.

The type was the basis for the successful D.XI for Fokker. But due to the many delays the chance of further orders in America was lost.

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