The Fokker D.-Flugzeugwerke. Germany produced around 3,300 D.VII aircraft in the summer and autumn of 1918.v In service, the D.VII quickly proved itself to be a formidable aircraft. Fokker's chief designer, Reinhold Platz, had been working on a series of experimental planes, the V-series, since 1916. These planes were characterised by the use of cantilever wings, they gave greater lift and more docile stalling behaviour than conventional thin wings. In January 1918, Idflieg held a fighter competition at Adlershof. Fokker submitted the V.II along with several other prototypes. The V.II was flown but found to be tricky, unpleasant, and directionally unstable in a dive. In response to these complaints, Reinhold Platz lengthened the rear fuselage by one structural bay, and added a triangular fixed vertical fin in front of the rudder. When the modified V.II was flown, it was praised it as the best aircraft of the competition. Fokker immediately received a provisional order for 400 production aircraft. Aircraft availability was limited at first, but soon there were 407 on charge and larger numbers became available by the next month when D.VIIs achieved 565 victories. When the war ended in November, 775 D.VII aircraft were in service.