Fokker's Synchronizer
This initiated a concentrated phase of consideration of the interrupter gear concept. The Dutch aircraft designer Anthony Fokker was heavily involved in this process but the story of his conception, development and installation of a synchronisation device in a period of 48 hours (first found in an authorised biography of Fokker written in 1929) has been shown to be not factual. The available evidence points to a synchronisation device having been in development by Fokker's team including engineer Heinrich Lübbe, and probably based on Schneider's patent, for perhaps six months prior to the capture of Garros' machine.
In 1916 LVG and Schneider sued Fokker for patent infringement — the battle continued until 1933 and though the courts repeatedly found in Schneider's favour, Fokker refused to acknowledge the rulings, all the way to the time of the Third Reich in 1933.
The only known date that is certain in the development of Fokker's pioneering Stangensteuerung system is on May 16, 1915, when an officer of the Bavarian armed forces, working with Idflieg, alerted his province of Germany that "firing trials of an interesting nature, from a light monoplane, were to take place on the 19th of 20th of May". The trials were meant to take place at the famous Döberitz proving ground near Berlin, but no record of any sort remains to definitively state what happened there.
Fokker's team adapted their system to work with the new Parabellum MG14 machine gun fitted to a Fokker A.III unarmed single-seat monoplane (a military version of the Fokker M.5K) usually flown for almost the entire first year of hostilities in World War I by Leutnant Otto Parschau, marked with the IdFlieg number A.16/15. This aircraft, with factory serial number (or Werknummer) 216, for the Fokker E.I — was demonstrated on 19–20 May 1915 and shipped to the Western Front on 30 May 1915. The five M.5K/MG production prototypes, with Fokker factory serial numbers 191 through 194, and s/n 198, received the IdFlieg military serial numbers E.1/15 through E.5/15, followed Parschau's A.16/15 aircraft into military trials very shortly thereafter, with Leutnant Parschau himself receiving E.1/15 as the replacement for his then worn-out No. 216 aircraft, which was returned to the Fokker factory for further trials with the lMG 08 "Spandau" air-cooled machine gun.
The new gear used a cam attached to the propeller shaft that pressed on a long rod running to the trigger of the guns. The cam was set such that when the propeller was horizontal it pushed on the rod, and the rod in turn pressed the trigger to fire a bullet. The trigger operated by the pilot pulled the rod into position over the cam, essentially allowing the engine's own rotation to fire the gun.
The first victory using a synchronized gun-equipped fighter, based on late 20th century research of surviving German and French early World War I aviation records, is strongly believed to have occurred on 1 July 1915 when Leutnant Kurt Wintgens of Feldflieger Abteilung 6b, flying the Fokker M.5K/MG aircraft that bore IdFlieg's serial number 'E.5/15', forced down a French Morane-Saulnier Type L east of Lunéville. However the plane landed in French territory and the victory could not be confirmed, as with Wintgens' second engagement only three days later, against a second Morane Parasol. The first "confirmed" victory, in the official German records of that time, would finally go to Wintgens on July 15, 1915, after he was re-assigned to Feldflieger Abteilung 48 near Mühlhausen im Elsaß by downing a third Morane Parasol.
Sole possession of a working gun synchronizer enabled Germany to dominate the Western Front skies in a period known as the Fokker Scourge. Initially lacking a synchronizer, the Royal Flying Corps relied on pusher aircraft such as the Vickers F.B.5 Gunbus and the Airco D.H.2 in which the propeller was behind the pilot, and therefore out of the way of forward firing guns. Germany was protective of the synchronizer system, instructing pilots not to venture over enemy territory in case they were forced down and the secret revealed, but the basic principles involved were already common knowledge, and by the middle of 1916 several Allied synchronizer gears were already available in quantity.
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