Fokker-Leimberger: Difference between revisions

| name = Fokker-Leimberger

| image =

| caption = photo of the Fokker-Leimberger

| origin = {{flagcountry|[[German Empire}}]]

| type = Multi-barelled [[Machine gun]]

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| part_length = <!-- GeneralRanged weapon specifications -->

The Fokker-Leimberger used a rotary split-breech design known as the "nutcracker". In this design a temporary [[Chamber (firearms)|chamber]] is formed by joining the two cavities of touching, counter-rotating [[sprocket]]s.<ref name="Williams2005"/> The simplicity of the design was appealing, particularly because it contained no major parts using a [[reciprocating motion]], like the [[breechblock]] used in many other automatic weapons. Ignoring the various [[Strength of materials|material stresses]], the maximum rate of fire was thus theoretically limited only by the time needed to complete the burning of the propellant from each cartridge (although, practically, barrel heating is a far more serious constraint).<ref name="flight"/> Anthony Williams commented on this design that: "Fokker claimed that 7,200 rpm was achieved, but knowing Fokker, there is some reason to assume that that may have been slightly exaggerated. Problems occurred, of course, with cases bursting on the seam between the two cylinders."<ref name="Williams2005"/> Another "Fokker Split Breech Rotary Machine Gun, ca. 1930" was donated by [[Val Forgett]] to [[Kentucky Military Treasures]] in 1977; according to the museum record it "proved unsuccessful because of its inability to seal breech cylinders".<ref name="moments">{{cite web|title="Fokker Split Breech Rotary Machine Gun, ca. 1930"| url=http://www.lrc.ky.gov/record/Moments10RS/web/KMT%20legislative%20moment%2040.pdf|publisher = lrc.ky.gov / Kentucky Historical Society|quote="This test model of a rotary machine gun built for Dutch designer Anthony Fokker proved unsuccessful because of its inability to seal breech cylinders. Although an incomplete specimen, it is the only known extant example of the Fokker Split Breech Rotary Machine Gun. [...] Due to the unsatisfactory test results of this prototype, the project was abandoned. Other prototypes were destroyed. Donated by [[Val Forgett]], 1977.08.01|access-date=2013-07-23|archive-date=2010-03-17|archive-url=https://web.archive.org/web/20100317004533/http://www.lrc.ky.gov/record/Moments10RS/web/KMT%20legislative%20moment%2040.pdf|url-status=dead}}</ref><ref>{{cite web|url=http://kyhistory.pastperfect-online.com/35577cgi/mweb.exe?request%3Drecord%26id%3DB54DA4F4-8851-4F4D-ADC2-453181649430%26type%3D101 |title=Gun, Machine |access-date=2013-07-24 |url-status=dead |archive-url=https://web.archive.org/web/20140407093738/http://kyhistory.pastperfect-online.com/35577cgi/mweb.exe?request=record&id=B54DA4F4-8851-4F4D-ADC2-453181649430&type=101 |archive-date=2014-04-07 }}</ref> The British also experimented with this type of breech for aircraft guns in the 1950s, but abandoned it.<ref name="WilliamsGustin2004">{{cite book|author1=Anthony G. Williams|author2=Emmanuel Gustin|title=Flying Guns of the Modern Era|year=2005|publisher=Crowood|isbn=978-1-86126-655-2|page=55}}</ref> This type of breech has only been used successfully in low-pressure applications, such as the [[Mk 18 Mod 0 grenade launcher]].<ref name="Williams2005">Anthony G Williams (8 November 2005), [http://www.quarry.nildram.co.uk/Split%20Breech.htm SPLIT BREECH GUNS: THE NUTCRACKER AND THE 40MM MK 18] {{webarchive |url=https://web.archive.org/web/20070614202850/http://www.quarry.nildram.co.uk/Split%20Breech.htm |date=June 14, 2007 }}</ref>

The Fokker-Leimberger used percussion ignition with the firing pins mounted on a [[swashplate]]. No [[Extractor (firearms)|extractor]] was employed; the spent cases were simply left on the outgoing belt. The gun would have had to be pre-rotated in flight in order to ensure that when the trigger was pulled it would have fired at its maximum speed at once. SimilarlyAs to thein Gatling designs, the use of multiple barrels enabled air cooling of each barrel in the time between successive shots that were fired from the same barrel.<ref name="flight"/>

The development program that lead to the Fokker-Leimberger prototype was apparently initiated by the [[Idflieg]] through a circular sent to German firearms manufacturers on 16 August 1916. This document, authoredwhich was written by majorMajor Wilhelm Siegert, requested lightweight designs with a high rate of fire for use in German aircraft. It also suggested that external power sources be used for the automatic firing, like the aircraft engine itself or electrical power. The circular was answered by designs from various German companies. Besides Fokker, [[Siemens]], [[Autogen]] and [[Gabriel Szakats|Szakats]]-[[Gothaer Waggonfabrik|Gotha]] also submitted proposals. None of these entered mass production before the war ended, although the Siemens prototype was used on the Western front and claimed one aerial victory.<ref name="flight"/>

As with his other machine-gun-related designs, Fokker collaborated with [[Heinrich Lübbe|Heinrich W. Lübbe]] and with another engineer named Leimberger for this project. Initially they developed a simple adaptation of the [[Maxim gun|Maxim action]] (itself widely used in Germany inas the [[MG 08]]), driven by a crank from the engine. Their more ambitious project however employed the yet unproven split-breech action, in a 12-barrel design.<ref name="flight"/> The idea for this type of breech was not entirely new, having been patented in the US as early as 1861 (USPTO #32,316).<ref name="Williams2005"/> (Other US patents from the early 1920s indicate there was renewed experimentation with this design in the US as well.<ref>http{{Cite web|url=https://wwwpatents.google.com/patentspatent/US1328230|title = Machine-gun}}</ref><ref>http{{Cite web|url=https://wwwpatents.google.com/patentspatent/US1399119|title = Machine-gun}}</ref>)

* [[{{annotated link|Centrifugal gun]]}} (actively considered for aircraft armament by the US during WWI)

* [[{{annotated link|Fokker's synchronizer]]}}

[[Category:87.92×57mm mmMauser machine guns]]

[[Category:Trial and research firearms of Germany]]