Fokker D.IX / PW-6
After the Armistice in 1918, Anthony Fokker returned to Holland and began to develop a new series of fighter designs originating from the D.VII of First World War. The first to appear, in prototype form only, was the D.IX, powered by a 300-hp Wright-Hispano engine and was armed with two machine guns, flown for the first time in 1921, maximum speed was 220 kph. The prototype had a streamlined fuel tank built around the wheel axle, (like the C.I), but this tank was later removed upon delivery as PW-6 to the US Army Air Services. The sole prototype of the DI X was purchased for evaluation by the US Army Air Service and shipped to the USA in 1922, being assigned the designation PW-6. As evaluated by the USAAS, the aerofoil-section fuel tank was deleted, but the PW-6 was not considered to offer a sufficient advance over the D VII to warrant further development.
Of typical Fokker construction in employing a welded steel-tube fuselage and wooden wings each having two box spars, the D IX featured an aerofoil-shaped fuel tank between the main wheels as first tested by the V 36. Only one was built.
The D.IX was used as the design basis for the D.XI.
Max take-off weight: 1253 kg / 2762 lb
Empty weight: 874 kg / 1927 lb
Wingspan: 8.99 m / 29 ft 6 in
Length: 7.09 m / 23 ft 3 in
Height: 2.74 m / 8 ft 12 in
Wing area: 22 sq.m / 236.81 sq ft
Max. speed: 223 km/h / 139 mph
Cruise speed: 188 km/h / 117 mph
Range: 471 km / 293 miles