Fokker E.IV

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The Fokker E.IV was the final variant of the Fokker Eindecker fighter aircraft that was operated by Germany during the First World War. Given the Fokker designation of M.15, the E.IV was essentially a lengthened Fokker E.III powered by the 160 hp Oberursel U.III 14-cylinder radial engine. The boost in power over the 100 hp engine of the E.III was intended to enable the Eindecker to carry two or three machine guns, thereby increasing its firepower and providing redundancy if one gun jammed — a common occurrence at the time. However, the E.IV was a troubled design that never achieved the success of its predecessor and was soon out-classed by French and British fighters.

The prototype E.IV was accepted for testing by the German Inspektion der Fliegertruppen in September 1915. It was fitted with three forward-firing Spandau lMG 08 machine guns, mounted to fire upwards at 15°. Anthony Fokker demonstrated the E.IV at Essen but the complicated triple-synchronisation gear failed and the propeller was damaged. The third gun was removed and a simpler double-synchronisation system used which became the standard armament for production E.IVs and indeed for all subsequent German D-type biplane fighters. The angling of the guns was also abandoned, reverting to a 0° alignment.

The modified prototype underwent combat evaluation on the Western Front by Oberleutnant Otto Parschau in October 1915, making it the first twin-gun fighter in service. Leading German ace Oswald Boelcke evaluated the E.IV at Fokker's Schwerin factory in November. The pilots discovered that cramming a more powerful engine (the Oberursel U.III-a clone of the French Gnôme Double Lambda 160 hp 14 cylinder two-row rotary engine) into the Eindecker configuration did not produce a better aircraft — one pilot described it as "practically a flying engine". The inertial and gyroscopic forces of the spinning mass made the E.IV less manoeuvrable than the E.III and any loss of efficiency from the notoriously unreliable engine made the aircraft virtually uncontrollable, requiring the engine to be switched off. Turning under such conditions was exceedingly difficult because the E.IV still used wing warping instead of ailerons.

Only 49 E.IVs were built out of a total Eindecker production of 416 aircraft. Over half of the E.IVs entered service in June 1916 and the last were delivered in December 1916 by which time they were obsolete. All E.IVs served with the German Army except for one which was supplied to the Kaiserliche Marine.

1 Specifications
2 Related content

[edit] Specifications

[edit] General Characteristics

Crew: one
Length: 24 ft 7 in ( m)
Wingspan: 32 ft 9½ in ( m)
Height: 9 ft 1 in ( m)
Wing area: 172.2 ft² ( m²)
Empty: 1,027½ lb ( kg)
Loaded: 1,596 lb ( kg)
Maximum takeoff: lb ( kg)
Powerplant: 1x Oberursel U.III 14-cylinder two-row air-cooled radial engine, 160 hp ( kW)