Fokker’s Flying Razor

By January 1918, the last year of World War I, the French and British had introduced large numbers of new fighter designs that were superior to the German fighters both qualitatively and quantitatively.

The previously described Fokker D.VII, with its 160 horsepower Mercedes D.III inline engine, was just entering full scale production and was superior to any Allied fighter, but the supplies of the Mercedes were limited and it was clear another modern fighter was quickly needed.

To find the fighter, the German high command held a competition in April 1918 to choose another design with a readily available engine for side-by-side production with the D.VII.

Fokker submitted what superficially resembled a rotary-engined version of the D.VII with a parasol wing, but the new fighter was smaller and about half the weight of the D.VII. The wing was unique — thick and totally plywood covered with a deep airfoil, deeper than any previously used in a Fokker aircraft. The wing, like the upper wing of the D.VII, provided a high lift/low stall speed combination that allowed the fighter to maneuver very effectively at low speed and high altitude.
Fokker submitted two versions of the fighter for the competition. One, the V.26, which was used by the low-powered but readily available 110 horsepower Oberursel UR.II rotary engine (the Oberursel engine factory was owned by Fokker) while the other, the V.28, used either the 145 horsepower Oberursel UR.III rotary or 160 horsepower Goebel Goe.III rotary, both much more powerful but in short supply.

Though its engine had low power and its design was radically different from the other more conventional biplanes in the competition, the V.26’s low drag single wing and light weight meant it was quite fast, had an exceptional rate of climb (it was able to reach 6,000 meters in 16 minutes) and was also highly maneuverable.
Perhaps most importantly, it was much easier to build than any other World War I aircraft, and 400 were immediately ordered into production as the Fokker E.V (Eindecker, single wing).

It was hoped the production aircraft would be powered by either the UR.III or Goe.III, but neither engine was available in any quantity and the production examples all mounted the UR.II.

The first production examples of the E.V aircraft were shipped to Jasta 6 in late July and delivered sooner to Jasta 1, Jasta 19, Jasta 24 and Jasta 36.

Initially, the E.V showed excellent performance and was well received, allegedly being dubbed the “Flying Razor” by the Allies because of its small frontal area. Lt. Emil Rolff scored the first kill in an E.V on Aug. 17, 1918, but two days later he was killed when his E.V’s wing disintegrated in flight. Two more E.Vs crashed in the next two weeks because of the same problem, and on Aug. 24, the design was grounded and production was stopped for an investigation of the wing failures.

The wing failures were never fully explained. Fokker later said they were caused by the Army technical bureau, which had forced him to modify the original design by over-strengthening the rear main spar to the level of a biplane, thus moving the wing’s center of flex too far back, causing the wing to twist and fail.
The problem was solved by reverting to his original design and reducing the stiffness of the aft wing spar, thus moving the center of flex forward and eliminating the twisting.

Other accounts say the source of the wing failures was in the construction. In some cases, excess material on the spars was trimmed away, leaving them dangerously weak, and the wing certainly leaked. This led to rain water being trapped inside the wings and rotting the plywood. The new wings had strengthened spars and internal varnishing for waterproofing.

Tests showed that, when properly constructed, the E.V wing had a considerable margin of safety and production resumed in October 1918 with improved quality control measures. At that point, all fighters were receiving the “D” appellation, so the E.V became the D.VIII.

The first new examples of the D.VIII started arriving at Jasta 11 in late October, a few weeks before the end of the war. Eighty-five were eventually delivered, one of which was credited with the last air kill of the war.

Two-hundred-eighty-nine E.Vs/D.VIIIs were built, but most were waiting for the new wings when the armistice was signed. Some served in the post-war era Polish air force and others were sent to Holland, Italy, Japan, the U.S. and England for testing.

The rest were scrapped in accordance with conditions set forth in the armistice.
One D.VIII was tested at McCook Field (now Wright Patterson Air Force Base) by the engineering division of the U.S. Army Air Service. The test pilot, Lt. Leigh Wade, noted “(The D.VII) takes off very quickly, climbs very rapidly and is very maneuverable. It is very easy to fly, and the controls are sensitive. It is tail heavy but so light on the controls that it is not tiresome to fly. The visibility is very good (and) the airplane lands very slowly.”

His only criticism was that the engine controls were poorly located — quite a tribute to the performance of an aircraft that used half the horsepower of Allied fighters of the same period.

(For questions or comments, contact Dr. Michel at marshall.michel@ramstein.af.mil.)