RC Article #1

AIRCRAFT DESCRIBED: FOKKER D VII

The V.11, as it was first known at the Fokker works at Schwerin, became, after slight modification, the prototype for the D VII and was presented for official evaluation in the first competition held for D type (i.e. single-seat fighters) machines held at Johnnisthal flying field early in 1918. The decision of the Front Line pilots, who were invited t test the machines, was unanimous in favour of the Fokker D VII and large contracts were awarded to Fokker. Orders were also given that Albatros Werke and their Austrian subsidiary O.A.W. (Oesterreichische Albatros Werke), should build the D VII under licence.

Both Albatros firms adopted their own, different, standards and although the machine all looked alike they were, in fact, different in detail and few components were completely interchangeable. In construction, the D VII was basically similar to the Dr I, the same formula of wooden cantilever wings with welded steel tube fuselage being adhered to. The wings differed from the Dr I in having two-spars instead of a single compound spar, but the same type plywood leading edge was retained. An unusual feature was the "one-piece" lower wing. To accommodate this, a 'cut-out" was arranged in the lower longerons to allow the spars to go right through the fuselage; the wing was bolted in and a metal panel fitted under it to fair off the bottom fuselage contour. Ribs were of this three-ply with narrow flanges tacked all round both sides of the perimeter thus forming a sandwich with the rib as the 'meat". A point to be noted is that the top surfaces of the wings were perfectly flat and did not possess the slightest degree of anhedral as has been shown in the past. Ailerons were of welded steel tube and the trailing edge was once again of wire. The fuselage was a straightforward braced box-girder, although forward of the cockpit the structure appeared somewhat complex where the engine bearers were incorporated. Metal panels covered the sides back to the lower wing leading edge, and back to the cockpit on the top decking. Decking aft of the cockpit was in the form of a plywood panel over which the fabric was stretched. Apart from the metal panels forward, the whole airframe was fabric covered. Variations in louvers, access doors and exhaust manifold occurred; on some D VIIs the nose was not "cut-down" on the starboard side but the exhaust was ducted down inside the fuselage with just a single outlet pipe projecting through the side. Both Hein and Axial airscrews were fitted and differed slightly in diameter (about ¾ in.) and profile.

The success of the D VII was attributable to the fact that it was a fairly easy, yet responsive, machine to fly, with an-apparent-ability to make a good pilot out of a mediocre one; also it retained extreme controllability at its ceiling. With these points went a propensity for being able to "hang on its prop" to shoot at an opponent, when other machines would have waffled, if not spun, out of a stall. Standard power unit of the D VII was the Mercedes D IIIa motor of about 170 h.p. It might be well to mention here that one often finds references to Mercedes engines of 160, 170, 180 and 200 h.p., but they were all practically the same basic D III 160 h.p. motor with different compression ratios to improve the ceiling. They were all rated at 160 h.p. for take off and it only being permitted to use the additional power at altitude. Later in the year the V.24 was introduced with the comparatively new 185 h.p. B.M.W. engine, and was known as the Fokker D VII F; it was a quite new model and these engines were not fitted retrospectively to old D VIIs.

The D VII was used for some years after the war by the Royal Dutch Air Services, and in the Dutch East Indies right up to the 1930's. Also, 142 were shipped to the U.S.A. after the Armistice, where some were flown with a variety of different engine installations.

COLOUR DETAILS:

D VIIs left the factories covered with the standard lozenge fabric which was pre-printed in various shades. Examination of several pieces of actual fabric leads to the conclusion that he main combination of colours was: sage green, salmon pink, yellow ochre, cobalt blue and violet, although the shades varied and the adjectives are only approximate. One well-preserved upper surface fabric examined contained two shades of the blue (ultramarine and prussian) and the Ochre was more a dark khaki shade; the other two colours of this combination being an almost true sage green and a quite bright violet. The pattern of the fabric was by no means regular, neither were all the lozenges exact hexagons. As a rough guide the size of the polygons may be taken as approximately 12 inches over their greatest length and 5 to 6 inches wide, but it must be emphasized that the sizes did vary. The rudder and a portion (sometimes all) of the fin were white: rib tapes were light blue. When a different undersurface fabric was used, the colours were largely the same as the upper surface, but of a lighter shade. Metal panels were either painted a plain dark green shade (olive), or in a patchwork of two or three shades roughly matching the fabric.

Staffel markings were added by the unit and usually confined to the tail, which was painted either a single colour or striped in varying proportions (diagpnally, laterally or lengthwise!). Pilot's identity, as a rule, was in the form of a coloured band(s) around the fuselage of the cockpit, but sometimes an initial, monogram or more intricate device was adopted. Rudolph Stark quotes Staftel 34 as having silver tails and the leader, von Griem, having two red bands round the fuselage.

TECHNICAL DATA:

Span 8.9 m. (29 ft. 3.5 in.).
Length 7.0 m (22 ft. 11 5/8 in.).
Height 2.75 m (9 ft. 2.25 in.).
Wing Area 20.5 m.sq.
Track 1.8 m (5 ft. 10 7/8 in.).
Weight empty 700 kg.
Weight loaded 850 kg.

Performance details are for aircraft tested June 1st, 1918.

                                170 h.p.        185 h.p.
Climb                        Mercedes         B.M.W.
1,000 m. (3,280 ft.)       3.80              2.50
2,000 m. (6,560 ft.)       6.80              5.25
3,000 m. (9,840 ft.)       12.0              8.50
4,000 m. (13,124 ft.)     18.5              11.70
5,000 m. (16,405 ft.)     31.5              16.00
6,000 m. (19,680 ft.)      N/A              21.25

Speed: 165 km. per hour at 2,000 m.

Armament: Twin fixed Spandau guns synchronized to fire through airscrew disc.