O.Thetford, P.Gray German Aircraft of the First World War (Putnam)

Putnam

Fokker V 9
  Built in the autumn of 1917, the V 9 again used many of the triplane subassemblies. The lower wing featured the single compound spar as in the Dr 1; the upper wing had two spars. No less than two pyramids of three struts supported the centre-section on either side, making a round dozen struts altogether. Engine was at first 80 h.p. Oberursel U O, but later the 110 h.p. U II was fitted. Span, 7.7 m. (25 ft. 3 1/8 in.). Length, 5.9 m. (19 ft. 4 3/8 in.). Area, 17.1 sq.m. (184.68 sq.ft.). Loaded weight, 580 kg. (1,276 lb.).


Fokker V 33
  In the summer of 1918 Platz made a partial redesign of the V 9, with a twin-spar lower wing fitted and with unbalanced, high-aspect-ratio ailerons fitted to the upper wing. The rudder at last made a departure from the previous rounded-comma pattern which, either with or without fin, had characterised all Fokker aircraft. The V 33 was a handy little machine which Anthony Fokker himself used as a personal aircraft. He took it back to Holland with him after the war, where it was flown from Schipo as late as 1922. Engine was 110 h.p. Oberursel U II.