Armstrong cannon
The term Armstrong cannons usually refers to breech loading guns with a breech block design named after their inventor, William Armstrong, 1st Baron Armstrong .
The term is used less often for a form of construction of gun barrels, also developed by Armstrong.
Colloquially, Armstrong cannon is also used in German-speaking countries to refer to the RML 17.72 inch gun that still exists in Malta .
construction
In 1854 Armstrong proposed to the Secretary of State for War a 3-pounder breech-loading cannon with a rifled barrel for testing purposes. The gun was later reamed to fire 5 pounder shells. The result convinced both in terms of range and accuracy. Armstrong developed the locking system further and used it in larger caliber cannons.
Weapons based on this design principle were introduced to the British Army in 1858 . Initially, only field artillery guns with a relatively small caliber were developed according to this principle. The bolt was used in 9-pounder mountain and light field guns with the caliber 2.5 inch (64 mm), the horse-drawn 9-pounder caliber 3 inch (76 mm) and the 12 pounder field guns caliber 3 inch.
Armstrong did not consider the locking system to be suitable for larger-caliber guns in principle, but developed appropriate weapons on the instructions of the responsible authorities: a 20 pounder (3.75 inch / 95 mm) as a field and ship gun, a 40 pounder (4.75 inch) inch / 121 mm) as a siege gun and a heavy 110-pounder cannon (7 inch / 180 mm). All of these calibers were used by the Royal Navy and - apart from the 20-pounder - were also used in New Zealand as field guns and coastal artillery.
The guns were manufactured at Elswick and Royal Arsenal .
Construction of the pipe
Armstrong used a soul pipe for his weapons , which was initially made from iron extracted by the puddle process . From 1863 steel with a carbon content of 0.05–0.15% was used, which was hardened in an oil bath. The core tube was surrounded by rings made of wrought iron , which held the tube together under tension. At the rear part of the tube, the closure piece, the side was trunnion attached to a ring trunnion ring mentioned were a glove. The trains were polygonal , the cross-section consisted of a 38-sided polygon.
The cast iron bullet , whose shape was based on a Minié bullet , was surrounded by a thin leather sleeve so that the overall diameter of the bullet was slightly larger than the bore of the barrel. The leather covering, in conjunction with the pulls, provided the bullet with a twist . This system was originally developed by Martin von Wahrendorff and Giovanni Cavalli in Sweden. The rifling of the bullet and the higher gas tightness brought about by the interaction of polygonal lines and leather patches ensured a greater range and accuracy compared to conventional muzzle-loaders.
Another element introduced by Armstrong was the narrowing of the pipe, which he called "grip". At the mouth of the shot chamber , the barrel had a slightly smaller diameter over a length of about 6 feet. This "grip" centered the bullet before it left the barrel, which contributed to better accuracy. At the same time the leather covering was stripped off.
On the grenade-side end of the propellant charge was an "oiler" ( lubricator ). It consisted of two thin metal sheets with tallow and linseed oil between them. The oiler was sealed to the pipe with a cardboard disc and beeswax. It was driven out of the barrel by the propellant charge after the grenade and reliably cleaned it of residues from the leather lining of the projectile.
The elements introduced by Armstrong - the structure with core barrel and reinforcing jacket rings - were also used in the later temporary transition to muzzle-loaders and, together with the polygonally drilled barrel, in some cases also in the more modern British rear-loading guns towards the end of the 19th century. When softer, yet stable materials were available for the shell of the grenade, the leather patches could be dispensed with. The reinforcement rings gave British guns their characteristic appearance of the time.
Construction of the lock
Constructively, it is a drop block lock . The block of solid material, as a vent-piece referred to, had on the front of a conical ring made of copper, the powder chamber ( powder chamber abdichtete). A screw screwed into the pipe from behind, screw breech , held the block and copper ring in place with a force- fit connection .
Loading and firing went as follows:
- the locking screw was unscrewed from its seat in the tube until the locking block was freely movable
- the breech block was pulled up until the tube was free
- The projectile and propellant charge (at that time in the form of cartridge pouches ) were inserted into the barrel from behind through the seat of the screw plug
- the ignition charge was inserted into the vertical mounting hole of the breech block
- the breech block was lowered into the tube
- the locking screw has been tightened
- the detonator was inserted into the primer charge
- the gunner ignited the igniter, which in turn ignited the ignition charge, which in turn ignited the propellant charge through the L-shaped ignition channel in the breech block
The construction of the breech block was complicated and consisted of several moving parts. The synchronization of these parts during the loading process required either special mechanical constructions or - if these were not available - the special care of the gun operator when loading and firing. The problem of the gas tightness of the closure was also not solved satisfactorily. Finally, the tube was weakened by the recess for the locking block at a highly stressed point - the powder chamber.
Nevertheless, the British used such guns successfully in the Second Opium War . The translator Robert Swinhoe reported after the attack on Pehtang:
"Numbers of dead Chinese lay about the guns, some most fearfully lacerated. The wall afforded very little protection to the Tartar gunners, and it was astonishing how they managed to stand so long against the destructive fire that our Armstrongs poured on them; but I observed, in more instances than one, that the unfortunate creatures had been tied to the guns by the legs. "
Return to muzzle-loaders
In 1863 an Ordnance Select Committee examined the suitability of breech loaders of the Armstrong system ( RBL - Rifle Breech Loading ) and muzzle loaders ( ML - Muzzle Loading ), but the production of Armstrong breech loaders was stopped as early as 1864 by a government decision. The committee stated in its final report:
"The many-grooved system of rifling with its lead-coated projectiles and complicated breech-loading arrangements is far inferior for the general purpose of war to the muzzle-loading system and has the disadvantage of being more expensive in both original cost and ammunition. Muzzle-loading guns are far superior to breech-loaders in simplicity of construction and efficiency in this respect for active service; they can be loaded and worked with perfect ease and abundant rapidity. "
Although the Armstrong breech loader was safer than the muzzle loader (in some cases the cast pipe tore open), the overall benefits were seen with the muzzle loader. The higher costs for weapons and ammunition for cannons manufactured according to the Armstrong system played a major role in this assessment. Both the Royal Navy and the British Army went back to muzzle-loaders in a row. Armstrong constructed a 40-pounder and a 64-pounder with an improved breech (horizontally running block and no breech screw), but the decision had already been made.
A serious disadvantage, however, turned out to be the low penetration capacity of the muzzle loaders. These cannons were designed as smooth barrel cannons, as loading the grenade from the front was not possible with a rifled barrel. Armstrong then developed special projectiles with wart-shaped elevations that slid in the fields of the cannon and thus made it possible to load from the front. However, the very gas-tight polygonal pipe had to be dispensed with, the pipes had conventional fields and trains. These cannons were listed as RBL - Rifle Breech Loading . The polygonal bore was only used again when the rear loader was again used.
literature
- Treatise on Ammunition 1877 , Naval & Military Press, 2003. ISBN 978-1-84342-532-8
- Alexander Lyman Holley, A Treatise on Ordnance and Armor , D. Van Nostrand, New York, 1865
Web links
Individual evidence
- ↑ after Holley, Treatise on Ordnance and Armor , 1865, pages 863-870, the patent awarded to Armstrong is in dispute, since Daniel Treadwell had already patented a corresponding construction and Armstrong copied this construction exactly
- ^ Treatise on Ammunition 1877, pp. 166-167
- ^ Robert Swinhoe, Narrative of the North China Campaign of 1860 (London: Smith, Elder & Co, 1861) p. 105.
- ^ WL Ruffell: The Gun - Rifled Ordnance: Whitworth . In: The Gun . Archived from the original on February 13, 2008. Retrieved February 6, 2008.