10 cm tower howitzer THM9

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The 10 cm tower howitzer TH M9 , consisting of an armored dome and cannon, was part of the more modern Austro-Hungarian fortifications during the First World War . All armored domes were manufactured by the Škoda works in Pilsen .

Intact tower howitzer TH M9 (The weather protection hood over the pipe muzzle and the observation opening is missing. It was attached to the transverse bar.)
Simplified view of a howitzer tank dome (here TH M9) with a depression mount (tube in negative elevation)
Simplified view of a howitzer tank dome (here TH M9) with a depression mount (tube in positive elevation)

draft

For the main armament of the new fortifications on the border with Italy and in Bosnia-Herzegovina , the original draft of the Colonel of Genius Otto Ellison von Nidlef provided for a separation of the gun carriage and turret shell , contrary to the usual application . This meant that the gun and turret were not rigidly connected to one another. Since the howitzer was designed as a minimal charter cannon , the entire turret did not have to be set in motion every time in the small side straightening area. Furthermore, it was feared that when it was fired, vibrations could arise that could possibly be transmitted to the gun via the tower bell and damage it. Another advantage was the possibility of expanding the gun with mount if required and using it elsewhere. The domes were made of very tough chrome-nickel steel (so-called P-2 steel) with a tensile strength of 45 kg / mm². The production costs for the dome and carriage amounted to 90,000 crowns .

dome

First of all, the prototype of a cannon dome with the designation M6 was made. This had a wall thickness of 160 to 200 mm, the pipe length was 1.475 m (L13). The dome weighed 15.8 t and was 20 cm shallower than the later model M9. However, this limited the negative elevation range to −8 °, which turned out to be unacceptable. In 1908 this dome was blown up on the artillery firing range in Felixdorf with a load of 25 kg of ecrasite . The dome was externally intact except for a 16 mm deep indentation, but inside, as with the impact of a squeeze-head grenade , metal blasting off had caused damage to the mechanics of the gun (this prototype, which had only twelve lateral straightening teeth, was later added to the factory as a medium gun Gschwent built in).

It was then decided to use different dimensions for the series production. The dome was given a crown thickness of 25 cm and a higher vault. The elevation angle could be improved to −15 ° by making an additional change to the pipe feeder. The maximum reference height was + 43 °, which made it possible to place shrapnel directly above the apron of the fortifications with the weakest load . The inner diameter of the armored dome was 2.68 m, the weight was 18.7 t. The dome was placed on a two-part armor made of 25 cm thick cast steel with a weight of 16.5 t. The armor was embedded in the concrete ceiling of the plant to a depth of 1 m. Access to the tower was via a staircase from below from a postern . This transition represented a weak point that was protected with an additional tank. Inside the dome was a revolving platform that sat at the bottom of the gun well. If the tower was to be rotated, it was raised by one millimeter by means of two lifting devices over four rubber buffers (the load was now on the platform), swiveled into the specified position and lowered again. The ring bead on the upper edge of the armored armor had 24 horizontal bores on its underside, each offset by 15 °. In these, the turret was locked in the firing position with the help of a locking bolt, which meant that the turret dome could not be twisted and wedged in the event of a side grenade impact. The Feinrichtung was then carried out via the gun itself, which could be readjusted by +/- 11.25 ° by the Minimalschartenlafette. The rotation in the segments took at least 15 seconds. To prevent the dome from being thrown off, six claws grabbed under the armor and secured it in this position. The tower could be raised up to 10 millimeters to remove jams. Firing with the tower dome raised was possible.

In the peacetime, a sheet metal cover was used as weather protection, which was placed over the entire dome. When preparing for combat readiness , only the openings in the dome were covered by a sheet metal hood. This was hung on a transverse bar above the openings.

gun

The gun was a further development of the M99 field howitzer . The caliber was 104 mm, the barrel length 176.5 cm (L / 17). The tube itself was made of cast bronze with progressive twist, a right-hand flat wedge lock with sleeve cover and a hydraulic return brake. It was mounted in a forward pivot mount that was attached to the pivoting platform. The carriage had two lifting devices, a gear arch leveling machine with worm gear and a relief device. The lateral direction took place via a worm drive. At a muzzle velocity of 370 m / s, a maximum range of 7.3 km could be achieved with both the M9 shrapnel grenade and the M11 high explosive grenade. The target was set using a sighting telescope with an independent attachment, which was very modern for the time. The rate of fire was a maximum of ten rounds per minute. It was installed in a depression mount.

ammunition

The most commonly used ammunition was the M9 shrapnel grenade with a weight of 16.2 kg and a filling of 758 11.7 mm lead bullets. The M11 ecrasite grenade was also used. All ammunition of the M99 light field howitzer could also be fired. The fired shell casings were refilled in the manipulation room of the fortress itself and loaded with 1st to 8th charges. To ward off infantry attacks, it was possible to keep the fire fuses of the shrapnel grenades up to 5 m.

Conclusion

Ejected tank turret from the Lusern plant , on the left the armored car , above the free-standing turret howitzer

Although the armored domes themselves could not be penetrated by the Italian 30.5 cm coastal mortars, the armor and coverings proved to be too weak. The gun wells were literally shot clear several times, whereupon the entire gun turrets overturned. The armored armor was also penetrated several times, which in individual cases led to the armored domes being thrown out. The range of the howitzers was not sufficient at all plants to return fire from the Italian armored plants Forte Monte Verena and Forte Campolongo, which were equipped with 15 cm long-barreled guns . To make matters worse, they were up to 500 m higher. The howitzers and their mounts were therefore moved to field positions where they served well.

The weak points of the armor were recognized as early as 1913 during attempts to fire with the M11 (30.5 cm) mortar, albeit too late. A successor model (TH M14) was then designed for the 10 cm and 15 cm tower howitzers with a 2.30 m deep and 30 cm thick armored armor. The armor of the dome was reinforced to 30 cm. The weight of the dome increased to 22.5 t, that of the armored car to 51 t. Intended for installation in the Valmorbia plant , work on it was stopped due to the outbreak of war.

See also

Individual evidence

  1. Toughness was given priority over higher hardness.
  2. ↑ Due to their design, the Italian mortars 30.5 cm were not able to shoot with the optimum barrel elevation. As a result, the maximum impact force was not achieved
  3. In the Gschwent plant, a 30.5 cm shell hit a tower dome at a shallow angle about 20 cm above the support joint as a dud. The projectile penetrated 19 cm deep into the armored steel and got stuck without causing damage inside.

literature

  • Rolf Hentzschel: Fortress war in the high mountains. Athesia, Bozen 2008, ISBN 978-88-8266-516-6 .
  • Erwin Anton Grestenberger: Imperial and Royal fortifications in Tyrol and Carinthia 1860–1918. Verlag Österreich ua, Vienna 2000, ISBN 978-3-7046-1558-9 .

Web links

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