Fokker Eindecker fighters
The Fokker Eindecker fighters were a series of German World War I monoplane single-seat fighter aircraft designed by Dutch engineer Anthony Fokker. Developed in April 1915, the first Eindecker was the first purpose-built German fighter aircraft and the first aircraft to be fitted with a synchronization gear, enabling the pilot to fire a machine gun through the arc of the propeller without striking the blades. The Eindecker gave the German Army's Air Service (then the Fliegertruppen des deutschen Kaiserreiches) a degree of air superiority from July 1915 until early 1916. This period, during which Allied aviators regarded their poorly armed aircraft as "Fokker Fodder", became known as the "Fokker Scourge".
Design and development
The Eindecker was based on Fokker's unarmed Fokker M.5K scout which in turn was based on the design of the French Morane-Saulnier H shoulder-wing monoplane, although it differed in using chrome-molybdenum steel tubing for the fuselage structure instead of wood. It was fitted with an early version of the Fokker gun synchronizer which controlled a single Parabellum MG 14 machine gun. Anthony Fokker personally demonstrated the system on 23 May 1915, having towed the prototype aircraft behind his touring car to a military airfield near Berlin.Image:Otto Parschau's A-16-15 Eindecker.jpg|thumb|right|A close-up photo of Otto Parschau's first Fokker monoplane, armed with a synchronized Parabellum MG14 machine gun in May 1915, which essentially became the "prototype" Fokker Eindecker.
''Leutnant'' Parschau and the ''Green Machine'' (A.16/15)
The history of the first Eindecker aircraft, which was used for Fokker's initial synchronizer trials, is closely associated with Leutnant Otto Parschau, who was allotted this aircraft, then a Fokker A-series unarmed scout with the serial number A.16/15, at the beginning of World War I. This aircraft had been bought in 1913 by Oberleutnant Waldemar von Buttlar, and requisitioned by the Fliegertruppe along with his commissioning as an officer in the Prussian Army at the outbreak of hostilities, and had been painted a shade of green, the color of von Buttlar's previous Jäger regiment. Parschau had served with the same surreptitiously named Brieftauben-Abteilung Ostende, in Belgium as Oberleutnant von Buttlar in November 1914, where the two German officers could have first made contact. Parschau eventually spent most of the first year of the war with this aircraft, flying it on both the Eastern and Western fronts. At some stage he had the words "Lt. Parschau" painted on the right upper side of the fuselage behind the cockpit. This aircraft had its main fuel tank located behind the cockpit.Near the end of May 1915, while it was based at Douai with Feldflieger Abteilung 62, the Fokker factory fitted Parschau's aircraft with the first trial version of the Fokker Stangensteuerung synchronizer and a Parabellum MG14 light machine gun, leaving the wing panels in the stock A.III airframe's shoulder-winged location while armed and in Parschau's use in May and June 1915. Parschau made several attempts at aerial combat during June 1915, but at this stage the gear proved very unreliable, the Parabellum gun repeatedly jamming. As no photos exist verifying any change in wing-panel anchorage location for Parschau's A.16/15 aircraft before its return to the Fokker factory a second time to serve as the "prototype" Eindecker airframe, the belief that it had been modified to have the standard mid-fuselage location used on the later production E.I airframes before its second return to the Fokker factory has not yet been proven, as it was lowered some time after the Fokker factory had received it back to be retained there, following Parschau's final use of it. The mid-fuselage wing mount modification was not fitted to the initial batch of five M.5K/MG production prototypes as originally built, with Otto Parschau's second Eindecker, the first M.5K/MG built bearing IdFlieg serial E.1/15 uniquely getting it sometime later, while in service. Production E.Is, and all further Fokker Eindeckers, were also fitted with the definitive version of the Stangensteuerung gear, with a large cam wheel replacing the early drive taken from the oil pump drive shaft.
Sheet metal parts finish on the Eindeckers
One distinctive feature of the appearance of all the sheet metal panelling on the Eindeckers was a special form of "dragged" engine turning performed on all their surfaces, both exposed and internal parts. This distinctive appearance on the sheet metal components of the Eindecker fuselage was also used on the earliest Fokker biplane fighters, like the Fokker D.I but had ceased to be used by the Fokker factory on its designs by the end of 1916.Fuel system details and flight characteristics
All the E.I to E.IV Eindeckers used a gravity fuel tank which had to be constantly filled by hand-pumping from the main fuel tank, which, starting with the Fokker E.II, was mounted behind the pilot; this had to be done up to eight times an hour. Both the rudder and elevator were aerodynamically balanced; there were no fixed tail surfaces. This combination rendered the Eindecker very responsive to pitch and yaw. For an inexperienced pilot, the extreme sensitivity of the elevators made level flight difficult; German ace Leutnant Kurt Wintgens, who along with Leutnant Parschau was the primary Fliegertruppe pilot responsible for bringing the first armed Fokker monoplanes into active service during the spring and summer of 1915, once stated "lightning is a straight line compared with the barogram of the first solo". However roll response was poor.Engine installations and associated changes
The main difference between the E.I and E.II was the engine, the former having the seven-cylinder 60 kW Oberursel U.0 rotary engine and the latter with the nine-cylinder 75 kW Oberursel U I. The larger diameter of the E.II's nine-cylinder rotary necessitated raising the upper nose paneling to match the larger-diameter cowl the U.I needed, which also caused the outer edges of the upper nose paneling to overhang the fuselage's upper longerons, making it necessary to extend the cowl. Production of the types, built in parallel, depended on engine availability. Many E.IIs were either completed as E.IIIs or upgraded to E.III standard when returned for repair.[Image:Fokker Eindecker takeoff profile view.jpg|thumb|left|Profile view of an Eindecker at takeoff.]
The definitive version of the Eindecker was the Fokker E.III, which used a slightly narrower-chord wing than earlier versions. Boelcke's Feldflieger Abteilung 62 began operating the E.III towards the end of 1915. A few E.IIIs were experimentally armed with two 7.92 mm calibre lMG 08 "Spandau" machine guns, while most E.IIIs and the production E.I through E.III Eindecker models used only one of the same model. The final variant was the Fokker E.IV which received a 119 kW Oberursel U.III, 14 cylinder twin-row rotary engine and was fitted with twin machine guns as standard, after repeated failure of an experimental triple-gun installation, which was initially intended be standard for the E.IV.
Total production for the entire Fokker E.I through E.IV series was 416 aircraft.
Operational history
The first Eindecker victory, though unconfirmed, was achieved by Leutnant Wintgens in the late afternoon of 1 July 1915 when, while flying one of the five M.5K/MG production prototype/"service test" aircraft, numbered 'E.5/15' near Lunéville, he forced down a French Morane-Saulnier L two seat "parasol" monoplane. By this time the first E.Is were arriving as supplementary equipment, one per unit as "attached" aircraft, for the ordinary Feldflieger Abteilung - initially to provide escort protection for their usual quantity of six two-seat reconnaissance biplanes per unit.Three days after his unconfirmed"victory, Wintgens downed another "Morane Parasol" with the same aircraft, and a fortnight after his initial engagement, on 15 July 1915, he became the first Eindecker pilot to be credited with an official victory.
The two most famous Eindecker pilots, both of Feldflieger Abteilung 62, were Oswald Boelcke and Max Immelmann, - who received his first production E.I Eindecker Eleven pilots scored five or more victories in the Eindecker. Boelcke, Immelmann, Parschau, Hans Berr, and Wintgens each passed eight victories while flying the Eindecker, and so received Germany's highest military decoration, the Pour le Mérite or "Blue Max".
The arrival in early 1916 of the French Nieuport 11 and the British Airco DH.2 brought the dominance of the Eindecker to an end, and with it, the "Fokker Scourge". Wintgens flew the E.IV version of the Eindecker long enough to have been confronted by the much more advanced SPAD S.VII fighter of French flying ace Alfred Heurteaux on 25 September 1916, which resulted in Heurteaux fatally bringing down Wintgens, as Huerteaux's victory number eight.
Variants
;Fokker M.5;Fokker M.5K
;Fokker M.5L
;Fokker M.5K/MG
;Fokker A.II
;Fokker A.III
;Fokker E.I
;Fokker E.II
;Fokker E.III
;Fokker E.IV
''Note: The Reinhold Platz-designed Fokker E.V bore no direct relation to the earlier Eindeckers, being a parasol aircraft, only built in small numbers before Germany decided to focus their production on the Fokker D.VIII.''