O.Thetford, P.Gray German Aircraft of the First World War (Putnam)
Fokker V 17
There is no record of types V 14 to V 16, and the V 17 was the first monoplane of the V series. It appeared in December 1917. Again the majority of components were from the Dr I. The cantilever wing was fabric covered and featured a single compound spar as in the Dr I wings, but its mid-wing location gave extremely poor downward-forward visibility from the cockpit. Engine was 110 h.p. Oberursel U II.
Fokker V 20
Rumoured to have been designed and constructed in 5 1/2 days during the first D types Competition, the V 20 can be said to have been little more than a hybrid between the V 17 and V 18 types. Engine was 160 h.p. Mercedes D III.
Fokker V 23
Development in the V 17, V 20 series, the V 23 differed little visibly. The wing was now of dual-spar construction and ply-covered, the ailerons were wholly inset; in fact, except for its location, the wing was much the same as that used on the later D VIII. This aircraft took part in the second D types Competition. Engine, 160 h.p. Mercedes D III. Loaded weight, 848 kg. (1,866 lb.), at which it climbed 1,000 m. (3,280 ft.) in 3 min. and to 5,000 m. (16,400 ft.) in 29.8 min.
Fokker V 25
Yet another version of the monoplane format with the wing now in the low-wing position. The wing was of twin-spar construction with ply-covering as on V 23; a vertical fin was added to the tail and a headrest aft of the cockpit. Fitted with 110 h.p. Oberursel U II engine, the machine took part in the second D types Competition. At a loaded weight of 564 kg. (1,285 lb.) it climbed 1,000 m. (3,280 ft.) in 1.7 min. and 5,000 m. (16,400 ft.) in 28.7 min.
W.Green, G.Swanborough The Complete Book of Fighters
FOKKER V 17 Germany
The first single-seat fighter monoplane to be designed by Reinhold Platz, the V 17 was ordered on 28 December 1917, and was demonstrated during the following month at Adlershof in the first D-type competition. Powered by a 110 hp Oberursel Ur II nine-cylinder rotary engine and armed with two synchronised 7,92-mm LMG 08/15 machine guns, the V 17 employed plywood skinning for both wings and fuselage. The wing, mounted in high-mid position, was manufactured in one piece and built up on two wooden box spars, and the rectangular-section fuselage was of welded steel-tube construction. Demonstrated at Adlershof by Anthony Fokker, the V17 failed to attract the interest of the Idflieg.
Time to 3,280 ft (1 000 m), 3.25 min.
Empty weight, 840 lb (381 kg).
Loaded weight, 1,237 lb (461 kg).
Length, 18 ft 11 1.8 in (5,77m).
FOKKER V 20 Germany
The V 20 single-seat fighter monoplane was claimed to have been designed and built within the course of six-and-a-half days. Its development was prompted by the demonstration of the V 17 at Adlershof during the first D-type competition, Anthony Fokker believing that a more powerful aircraft of essentially similar design stood a good chance of attracting a production contract. Accordingly, Reinhold Platz designed the V 20 around the 160 hp Mercedes D III six-cylinder water-cooled engine. Although of similar configuration to the V 17 and of the same structural concept, apart from utilising fabric skinning aft of the rear spar, the V 20 had no design commonality with the earlier monoplane prototype. It reach Adlershof before conclusion of the D-type competition, but evidently did not achieve the success for which Fokker had hoped as no further development was undertaken.
FOKKER V 23 Germany
Despite the lack of success attending the V17 and V 20 single-seat fighter monoplanes during the first D-type competition, Reinhold Platz - who, by this time, had established quite extraordinary design prolificity - was reluctant to relinquish the cantilever monoplane concept. Considering this to be aerodynamically ideal, he created further prototypes of this configuration for participation in the second D-type competition held in May-June 1918. The first of these was the V 23 powered by the 160 hp Mercedes D in engine and featuring a mid-mounted, plywood-covered, tapered two-spar wooden wing with inset ailerons which were also ply skinned. The fuselage was a rectangular welded steel-tube structure and the standard armament of paired and synchronised LMG 08/15 guns was intended. The V 23 was demonstrated at Adlershof during the contest, but was criticised for the view that was offered from the cockpit which was considered inadequate for combat. It was consequently rejected by the Idflieg without type testing, Fokker discontinuing development.
Max speed, 124 mph (200 km/h) at 6,560 ft (2 000 m).
Time to 3,280 ft (1000 m), 3.0 min.
Empty weight, 1,484 lb (673 kg).
Loaded weight, 1,880 lb (853 kg).
Span, 28 ft 8 in (8,73 m).
Length, 19 ft 0 1/3 in (5,80 m).
Height, 8 ft 8 in (2,65 m).
Wing area, 119.7 sqft (11,12 m2).
FOKKER V 25 Germany
Built in parallel with the V 23 for participation in the second D-type competition, the V 25 employed a similar structure but was of low- rather than mid-wing configuration, and was powered by a 110 hp Oberursel Ur II nine-cylinder rotary engine. Appreciably smaller and lighter than the mid-wing monoplane prototype, the V 25 offered superior manoeuvrability and better initial climb, but owing to its low-powered engine had little chance of success and its development, like that of the V 23, was abandoned after the competition.
Max speed, 124 mph (200 km/h) at sea level.
Time to 3,280 ft (1 000m), 1.7min.
Empty weight, 847 lb (384 kg).
Loaded weight, 1,243 lb (564 kg).
Span, 28 ft 7 3/4 in (8,73 m).
Length, 19 ft 5 1/2 in (5,93 m).
Height, 8 ft 7 1/2 in (2,63 m).
Wing area, 119.7 sq ft (11,12 m2).