View source for Engineering:1.59-inch breech-loading Vickers Q.F. gun, Mk II

{{Infobox weapon
|is_artillery=yes
|is_UK=yes
|is_ranged=yes
|image=1.59-inch Crayford gun photograph.jpg
|caption=The gun displayed on a non-standard mounting in 1917
|name=1.59-inch breech-loading Vickers Q.F. Gun, Mk&nbsp;II
|origin= United Kingdom
|used_by= United Kingdom
|wars=[[Social:World War I|World War I]]
|designer=
|design_date=
|manufacturer=[[Company:Vickers|Vickers]]
|prod_date=
|type=Light [[Engineering:Field gun|field gun]] and aerial cannon
|date=
|service=1917
|caliber= 1.59 in (40 mm)
|part_length=
|carriage=
|breech=Simple block
|rate=50 rounds in 30 minutes from aircraft reported
|velocity=Incendiary: 800 ft/s (244 m/s)<br>AP: 1,000 ft/s (305 m/s)<br>HE: 780 ft/s (238 m/s)
|cartridge=Incendiary, AP, and HE [[Engineering:Cartridge (firearms)|cartridges]]
|cartridge_weight=1.2 lbs (0.54&nbsp;kg) (high-explosive shell)
|range=
|max_range=
|recoil=7 to 7.5 in (148 to 159 mm)
|elevation=
|traverse=
|weight=47 lb (21.3&nbsp;kg)<br/> 90 lb (41 kg) including [[Engineering:Weapon mount|mounting]] stock and yoke-[[Engineering:Pintle|pintle]]
|length=
|crew=1
|number=
}}

The '''1.59-inch breech-loading Vickers Q.F. gun, Mk II''' was a British light artillery piece designed during [[Social:World War I|World War I]]. Originally intended for use in [[Earth:Trench warfare|trench warfare]], it was instead tested for air-to-air and air-to-ground use by aircraft. Although it fired shells and had no capability to launch [[Engineering:Rocket|rocket]]s, it was widely but misleadingly known as the "'''Vickers-Crayford rocket gun'''."

==Design==

[[Company:Vickers|Vickers]] designed the gun early in World War I, intending it as a piece of light artillery for use by infantry in [[Engineering:Trench|trench]]es attacking [[Engineering:Machine gun|machine gun]] positions and pillboxes. To make it portable for infantry use, it was very small and light for a gun of its calibre.<ref name="Cannon" /> Its light construction dictated a low [[Physics:Muzzle velocity|muzzle velocity]], which resulted in it having a short range. It was too light to withstand the detonation of standard British explosive propellants, so its ammunition used [[Chemistry:Ballistite|ballistite]] packed in cambric bags instead.<ref name="Woodman"/> The gun fired a 1.2-pound (0.54&nbsp;kg) high-explosive shell at 800 feet (244 meters) per second; it also could fire an armour-piercing round at 1,000 feet (305 meters) per second. The gun{{'}}s 40x79R cartridge was a shortened version of the naval 40x158R anti-aircraft cartridge, with the shell case reduced from 158&nbsp;mm (6.22 inches) to 79&nbsp;mm (3.11 inches) in length.<ref name="Cannon">{{Citation|url=http://www.quarryhs.co.uk//cannon_pioneers.htm |title=The Cannon Pioneers: The Early Development and Use of Aircraft Cannon |quote=This article is a summary of information in 'Flying Guns – World War 1: Development of Aircraft Guns, Ammunition and Installations 1914-32' by Anthony G Williams and Emmanuel Gustin. |last=Williams |first=Anthony G.}}</ref><ref name=37mm40mm>{{Cite web |url=http://www.quarryhs.co.uk/37-40mm.htm |title=37mm and 40mm Guns in British Service |access-date=9 November 2014 |archive-date=3 February 2020 |archive-url=https://web.archive.org/web/20200203213225/http://quarryhs.co.uk/37-40mm.htm |url-status=dead }}</ref>

The gun was, for ease of use in trenches, single shot; the gunner had to extract the empty case of a fired cartridge manually and reload the gun after firing each round, which gave it a low rate of fire.<ref name=37mm40mm/> It had a simple block breech with percussion gear, and was mounted on a non-recoiling frame consisting of a hydraulic buffer, trunnion block, and rear guide tube. Hand grips were mounted on the guide tube.<ref name="Woodman">{{Cite web |url=http://www.quarryhs.co.uk/Woodman.htm |title=Author's amendment and updating list, 28 July 1993, for Woodman, Harry, ''Early Aircraft Armament: The Aeroplane and the Gun up to 1918''. |access-date=9 November 2014 |archive-date=30 December 2019 |archive-url=https://web.archive.org/web/20191230012543/http://quarryhs.co.uk/Woodman.htm |url-status=dead }}</ref> The gun had a large [[Engineering:Muzzle brake|muzzle brake]] to reduce [[Engineering:Recoil|recoil]].<ref name="Cannon" />

Vickers manufactured the gun at its plant in Crayford, England.

==Operational history==

The concept of using the 1.59-inch breech-loading Vickers Q.F. gun, Mk II in the trenches was superseded by that of the trench mortar, which was simpler, cheaper, easily portable, and more effective.<ref name="Woodman" />
[[File:1.59-inch Crayford gun ammunition diagrams 1917.jpg|thumb|left|Incendiary (left) and armour-piercing (right) rounds for the 1.59-inch breech-loading Vickers Q.F. gun, Mk II ]]
With the gun no longer wanted in the trenches, it was decided to adapt it for use on aircraft as an air-to-air weapon against [[Physics:Airship|airship]]s and [[Philosophy:Observation balloon|observation balloon]]s and for use against ground targets such as trains, ammunition dumps, and [[Engineering:Tank|tank]]s. When mounted aboard aircraft, the gun could fire incendiary, armour-piercing, and high-explosive cartridges. The incendiary shell in flight emitted very hot flames from two openings in its base, which made it look as if the gun had fired a rocket; this led to the gun{{'}}s misleading but widely used name of "Vickers-Crayford rocket gun".<ref name="Woodman" />

The gun was approved for aircraft use in 1917. For operational testing, it was fitted to [[Engineering:Royal Aircraft Factory F.E.2|F.E.2b]] aircraft of Nos. 100 and 102 squadrons, Royal Flying Corps, in April 1917. The squadrons tested it on night operations and reported mixed results. No. 102 Squadron{{'}}s captain, T. J. C. Martin, an F.E.2b pilot, reported that his observer stopped a train after firing about 30 rounds at it, and that it took his observer 30 minutes to fire 50 aimed rounds; he submitted an enthusiastic report on the gun and its potential. No. 100 Squadron, however, reported problems with the gun: Its report stated, "Sometimes the shell does not leave the [[Engineering:Gun barrel|barrel]] for some time after the [[Engineering:Firing pin|striker]] has been released;"<ref name="Woodman" />
in one incident, a gunner who thought the gun had misfired was about to open the breech to remove what he thought was a hung round when the shell went off in a shower of sparks. This led the squadron to require gunners to wait five minutes before removing a misfire. The gun also suffered from weak [[Engineering:Trigger (firearms)|trigger]] springs and some of its shells had defective primers.<ref name="Woodman" />

The British hoped that the gun would prove useful in attacking German airships over the United Kingdom, mounted on British fighters so as to be able to fire upward into an airship flying above the fighter. Plans to mount the gun on the [[Engineering:Parnall Scout|Parnall Scout]] fighter apparently did not come to fruition.<ref name="Cannon" /> At the request of the War Office, Vickers built a single [[Engineering:Prototype|prototype]] of the [[Engineering:Vickers F.B.25|Vickers F.B.25]] two-seat night fighter to employ the gun, but the F.B.25 failed official tests and crashed in May 1917 on the way to Martlesham Heath. The Royal Aircraft Factory N.E.1 night fighter was also constructed to the same specification to carry the gun; though it flew well, it lacked the performance for use as a night-fighter.<ref name="Woodman" />
[[File:Vickers F.B.25.jpg|thumb|right|200px|The lone Vickers F.B.25 night fighter prototype, mounting a 1.59-inch breech-loading Vickers Q.F. gun, Mk II in its forward cockpit]]
After the failure of both the F.B.25 and N.E.1 to win production orders, interest in operational employment of the 1.59-inch breech-loading Vickers Q.F. gun, Mk II appears to have waned; moreover, the introduction of an incendiary round for use in machine guns had made aerial use of the gun less desirable.<ref>[http://www.flightglobal.com/pdfarchive/view/1919/1919%20-%200764.html ''Flight'' p. 764] 12 June 1919</ref> The gun was withdrawn from use entirely, apparently after the end of World War I, except for use by specially trained personnel.<ref name="Woodman" />

==See also==
*[[Engineering:COW 37 mm gun|COW 37 mm gun]]

==Notes==
{{Reflist}}

==References==
*[http://www.quarryhs.co.uk/Woodman.htm Author{{'}}s amendment and updating list, 28 July 1993] {{Webarchive|url=https://web.archive.org/web/20191230012543/http://quarryhs.co.uk/Woodman.htm |date=30 December 2019 }}, for Woodman, Harry, ''Early Aircraft Armament: The Aeroplane and the Gun up to 1918'', since published as Williams, Anthony G. and Emmanuel Gustin, ''Flying Guns World War I: Development of Aircraft Guns, Ammunition and Installations 1914-32'', Marlborough, Wiltshire, United Kingdom: Crowood Press, 2003, {{ISBN|1-84037-396-2}}.
*[http://www.quarryhs.co.uk/37-40mm.htm 37mm and 40mm Guns in British Service] {{Webarchive|url=https://web.archive.org/web/20200203213225/http://quarryhs.co.uk/37-40mm.htm |date=3 February 2020 }}
*[http://www.quarryhs.co.uk/cannon_pioneers.htm The Cannon Pioneers: The Early Development and Use of Aircraft Cannon] {{Webarchive|url=https://web.archive.org/web/20170929050054/http://www.quarryhs.co.uk/cannon_pioneers.htm |date=29 September 2017 }}


[[Category:Field artillery]]

{{Sourceattribution|1.59-inch breech-loading Vickers Q.F. gun, Mk II}}