.gif)
21 cm K 12 (E)
Encyclopedia
The 21 cm Kanone 12 in Eisenbahnlafette (21 cm K 12 (E)) was a German railroad gun used in the Second World War.
continued theoretical research on a replacement for the Paris Gun
during the Weimar Republic
-era, but it was the Nazi government that finally authorized funding for experiments to solve some of its worst problems. The extremely high velocities used by the Paris Gun to attain the stratospheric heights necessary for extreme range caused enormous wear of the barrel. So much so that the shells had to be made in gradually increasing diameter to suit the rate of wear. Even then barrel life was merely 50 rounds. It is believed that the one Paris Gun destroyed by a premature detonation in the bore was caused by loading one of the serially-numbered shells out of order. Thus Krupp decided to use only 8 grooves in the barrel and to machine matching ribs or splines on the shells to obviate the need for a massive copper driving band
to start the shell spinning without shearing off, which had been one of the prime causes of the excessive barrel wear in the earlier weapon. Gas sealing would be handled by a copper band, mounted in the place normally occupied by the driving band, with an asbestos
and graphite
packing to form the initial seal. A number of test barrels, known as the 10.5 cm K 12 M, and shells were made in 1935 and were compared to a conventionally rifled barrel (the 10.5 cm K 12 MKu). The tests proved that Krupp's concept was correct.
The K 12 (E) was mounted on a simple box-girder carriage, which was carried on two subframes which were in turn mounted on double bogies. The barrel was mounted in a ring cradle with a hydropneumatic recoil system. Two more hydropneumatic systems were connected to the subframes, which allowed the entire carriage to recoil some 98 centimetres (38.6 in). For transport the gun itself was disconnected from its recoil system and drawn back some 1.5 metres (4.9 ft) to reduce the mounting's overall length and allow it to fit in the normal railroad loading gauge. The barrel's extreme length required external bracing to prevent it from bending under its own weight. Its trunnions were placed as far forward as possible to balance the barrel and minimize the force necessary to elevate it. This placed the breech perilously close to the ground and a hydraulic jacking system was built in each subframe to elevate the mount 1 metres (3.3 ft). Unfortunately it was impossible to load the weapon in this position and it had to be lowered between every shot.
The K 12 (E) could be fired from any curved section of track, a Vögele turntable, or from its special firing track. This prefabricated T-shaped track was carried on the gun train and deployed by a special crane wagon. Once the front bogies were at the crossover at the top of the T they were then jacked up and turned with the subframe 90° and then lowered onto the crosstroke of the T. The gun was then traversed by an electric motor to the bogies and it was clamped to the track once laid onto the target. It fired HE
shells weighing 107.5 kilograms (237 lb).
The first weapon was completed in 1938 and delivered to the Army Heer
in March 1939. It was successful, although the necessity to jack it up and down between shot wasn't well received by the Heer. Trying rectify this problem Krupp discovered that hydro-pneumatic balancing-presses could work at much greater weights and pressures than previously believed. They redesigned the mounting with the trunnions as far forward as possible and increased the recoil stroke to 150 centimetres (59.1 in). The new design was delivered during the summer of 1940 and called the K 12 N (E). The first gun was retrospectively called the K 12 V (E).
They spent the war assigned to Artillerie-Batterie 701 (E) along the Channel
coast. The British recovered shell fragments near Chatham
, Kent
, some 88 kilometres (54.7 mi) from the nearest point on the French coast.
Design & History
KruppKrupp
The Krupp family , a prominent 400-year-old German dynasty from Essen, have become famous for their steel production and for their manufacture of ammunition and armaments. The family business, known as Friedrich Krupp AG Hoesch-Krupp, was the largest company in Europe at the beginning of the 20th...
continued theoretical research on a replacement for the Paris Gun
Paris Gun
The Paris Gun was a German long-range siege gun used to bombard Paris during World War I. It was in service from March-August 1918. When it was first employed, Parisians believed they'd been bombed by a new type of high-altitude zeppelin, as neither the sound of an airplane nor a gun could be heard...
during the Weimar Republic
Weimar Republic
The Weimar Republic is the name given by historians to the parliamentary republic established in 1919 in Germany to replace the imperial form of government...
-era, but it was the Nazi government that finally authorized funding for experiments to solve some of its worst problems. The extremely high velocities used by the Paris Gun to attain the stratospheric heights necessary for extreme range caused enormous wear of the barrel. So much so that the shells had to be made in gradually increasing diameter to suit the rate of wear. Even then barrel life was merely 50 rounds. It is believed that the one Paris Gun destroyed by a premature detonation in the bore was caused by loading one of the serially-numbered shells out of order. Thus Krupp decided to use only 8 grooves in the barrel and to machine matching ribs or splines on the shells to obviate the need for a massive copper driving band
Driving band
The driving band or rotating band is part of an artillery shell, a band of soft metal near the middle of the shell, typically made of gilding metal, copper or lead...
to start the shell spinning without shearing off, which had been one of the prime causes of the excessive barrel wear in the earlier weapon. Gas sealing would be handled by a copper band, mounted in the place normally occupied by the driving band, with an asbestos
Asbestos
Asbestos is a set of six naturally occurring silicate minerals used commercially for their desirable physical properties. They all have in common their eponymous, asbestiform habit: long, thin fibrous crystals...
and graphite
Graphite
The mineral graphite is one of the allotropes of carbon. It was named by Abraham Gottlob Werner in 1789 from the Ancient Greek γράφω , "to draw/write", for its use in pencils, where it is commonly called lead . Unlike diamond , graphite is an electrical conductor, a semimetal...
packing to form the initial seal. A number of test barrels, known as the 10.5 cm K 12 M, and shells were made in 1935 and were compared to a conventionally rifled barrel (the 10.5 cm K 12 MKu). The tests proved that Krupp's concept was correct.
The K 12 (E) was mounted on a simple box-girder carriage, which was carried on two subframes which were in turn mounted on double bogies. The barrel was mounted in a ring cradle with a hydropneumatic recoil system. Two more hydropneumatic systems were connected to the subframes, which allowed the entire carriage to recoil some 98 centimetres (38.6 in). For transport the gun itself was disconnected from its recoil system and drawn back some 1.5 metres (4.9 ft) to reduce the mounting's overall length and allow it to fit in the normal railroad loading gauge. The barrel's extreme length required external bracing to prevent it from bending under its own weight. Its trunnions were placed as far forward as possible to balance the barrel and minimize the force necessary to elevate it. This placed the breech perilously close to the ground and a hydraulic jacking system was built in each subframe to elevate the mount 1 metres (3.3 ft). Unfortunately it was impossible to load the weapon in this position and it had to be lowered between every shot.
The K 12 (E) could be fired from any curved section of track, a Vögele turntable, or from its special firing track. This prefabricated T-shaped track was carried on the gun train and deployed by a special crane wagon. Once the front bogies were at the crossover at the top of the T they were then jacked up and turned with the subframe 90° and then lowered onto the crosstroke of the T. The gun was then traversed by an electric motor to the bogies and it was clamped to the track once laid onto the target. It fired HE
Explosive material
An explosive material, also called an explosive, is a reactive substance that contains a great amount of potential energy that can produce an explosion if released suddenly, usually accompanied by the production of light, heat, sound, and pressure...
shells weighing 107.5 kilograms (237 lb).
The first weapon was completed in 1938 and delivered to the Army Heer
Heer (1935-1945)
The Heer was the Army land forces component of the German armed forces from 1935 to 1945, the latter also included the Navy and the Air Force...
in March 1939. It was successful, although the necessity to jack it up and down between shot wasn't well received by the Heer. Trying rectify this problem Krupp discovered that hydro-pneumatic balancing-presses could work at much greater weights and pressures than previously believed. They redesigned the mounting with the trunnions as far forward as possible and increased the recoil stroke to 150 centimetres (59.1 in). The new design was delivered during the summer of 1940 and called the K 12 N (E). The first gun was retrospectively called the K 12 V (E).
They spent the war assigned to Artillerie-Batterie 701 (E) along the Channel
English Channel
The English Channel , often referred to simply as the Channel, is an arm of the Atlantic Ocean that separates southern England from northern France, and joins the North Sea to the Atlantic. It is about long and varies in width from at its widest to in the Strait of Dover...
coast. The British recovered shell fragments near Chatham
Chatham, Medway
Chatham is one of the Medway towns located within the Medway unitary authority, in North Kent, in South East England.Although the dockyard has long been closed and is now being redeveloped into a business and residential community as well as a museum featuring the famous submarine, HMS Ocelot,...
, Kent
Kent
Kent is a county in southeast England, and is one of the home counties. It borders East Sussex, Surrey and Greater London and has a defined boundary with Essex in the middle of the Thames Estuary. The ceremonial county boundaries of Kent include the shire county of Kent and the unitary borough of...
, some 88 kilometres (54.7 mi) from the nearest point on the French coast.