Compressed Air Trench Mortar

[bushfighter]

There is an interesting photograph here:

http://www.worldwar1.com/tripwire/smtw.htm

Harry

[Tom W.]

You're right; a very interesting photo:

[Ian Riley]

There is an interesting photograph here:

http://www.worldwar1...ipwire/smtw.htm

Harry

For those serious enough not to be distracted by the siren-like Ms Theda Bara and able to get to the foot of page 3 of the link ....

Is this the De Breviare mortar, a French gun running on acetylene and air apparently, that was being trialled in Second Army towrds the end of 1915

Ian

[nigelfe]

_{Austro-Hungary had an assortment of pneumatic mortars, there're pictures in Ortner's tome, including a 12cm being used by Turks. I think Germany may had had some as well.}

[egbert]

_{Austro-Hungary had an assortment of pneumatic mortars, there're pictures in Ortner's tome, including a 12cm being used by Turks. I think Germany may had had some as well.}

It is very difficult to read this

[bmac]

It is an Obusier Pneumatique de 86 mm Boileau-Debladis, a small number of which started to be manufactured in January 1916, Other similar mortars were the Obusier Pneumatique de 60 mm Mle 1915 et 1916 Brandt, the Obusier Pneumatique SM 1916 Dormoy-Chateau and the Obusier Pneumatique Hachette de 86 mm, manufactured between September and December 1915.

[Michael Haselgrove]

Thanks for the photo, bushfighter. Attached are several photos of an (inert) 86mm bomb as held by the soldier on the right of the photo.

Regards,

Michael H.

[centurion]

Some more pneumatic mortars from various countries

The 10.5 cm Luftminenwerfer M 15 (Pneumatic Trench Mortar) was a medium mortar used by the KuK. Developed by the German firm of Ehrhardt & Sehmer, it was a rigid-recoil, muzzle-loading mortar on a fixed base that used compressed air to propel the mortar bomb to the target. Each cylinder of compressed air lasted for fifteen shots. The great advantage was that it had no firing signature, unlike conventional mortars with their smoke and flash. For this reason they were to be used at night

A batch of 25 mortars, 250 cylinders of compressed air and 10,000 bombs complete with fuses was ordered on 31 July 1915 for combat evaluation, but the company proved to be unable to deliver the mortar bombs. Instead they had to be manufactured by the Army itself. A slightly improved model was offered by Ehrhardt & Sehmer at the end of March 1916, but it was rejected because of the lack of effectiveness of the ammunition, difficulty in procuring said ammunition and its poor range.

Ten trench mortar platoons, each with two weapons, were formed and deployed in February 1916, mainly to the Eastern Front.

The 12 cm Luftminenwerfer M 16 (Pneumatic trench mortar) was a medium mortar used by the KuK. It was developed by Austria Metal Works in Brno from an earlier, rejected, 8 cm project. It was a rigid-recoil, smooth-bore, breech-loading design that had to be levered around to aim at new targets. It was very simple in that the shell closed the top of the chamber and was retained by a "gripper" until the air pressure was deemed sufficient and the gripper was manually released, which fired the weapon. An additional barrel could be fitted to extend the range. A cylinder of compressed air was good for eleven shots.

After an evaluation on 23 November 1915 it was deemed superior to the German designs already in service (10.5 cm Luftminenwerfer M 15 and 15 cm Luftminenwerfer M 15 M. E.) in range and accuracy and a batch of 100 mortars and 50,000 bombs was ordered at the beginning of 1916. Some 280 were at the front by the end of 1916 and 930 by the end of 1917. In addition to Austria Metal Works it was produced by Brand & L'Huillier and the machine factory at Brno-Köningsfeld. Some improvements must have been made over the course of the production run because late-war documents refer to the original design as the M 16a (alte?), but what exactly was changed is unknown.

The 15 cm Luftminenwerfer M 15 M. E. (Pneumatic Trench Mortar Maschinenfabrik Esslingen) was a medium mortar used by Germany and the KuK . It was developed by the German firm Maschinenfabrik Esslingen in response to a German requirement. Its initial testing was observed by a KuK representative and his favourable report convinced them to order a batch of five for comparative testing. It was evaluated on 21 September 1915 and four weapons were sent off for combat trials at the end of October 1915, which were presumably favourable.

The barrel was mounted on a central pivot attached to a base plate, presumably with 360° of traverse. A single cylinder of compressed air was good for twelve shots.

The Model II incorporated minor improvements suggested by both the Austrians and German pioneer troops and was evaluated at the end of 1915. It was deemed satisfactory and another hundred were ordered. However, they were soon made obsolete by the better performance of the 12 cm Luftminenwerfer M 16 and shelved before the production run was finished.

The 20 cm Luftminenwerfer M 16 (Pneumatic trench mortar) was a heavy mortar used by the KuK. It was developed by Austria Metal Works in Brno from their earlier 12 cm Luftminenwerfer M 16. It was a rigid-recoil, smooth-bore, muzzle-loading design that had to be levered around to aim at new targets. It was very simple in that the shell closed the top of the chamber and was retained by a "gripper" until the air pressure was deemed sufficient and the gripper was manually released, which fired the weapon. The barrel was fixed at 45° elevation and range was adjusted by varying the air pressure, but an additional barrel could be fitted to extend the range. A single cylinder of compressed air was only good for four to six shots. It was loaded onto a two-wheel cart for transport.

20 were ordered at the end of May 1916 after trials in the spring. Another 80 were ordered in November 1916. In service it wasn't as successful as its smaller brother due to its greater weight and much greater requirement for compressed air. It was superseded by the 26 cm Minenwerfer M 17.

The Brandt pneumatic mortar was a British design used by the French The Brandt pneumatic mortar grenade was launched by a small trench weapon developed in 1915 for infantry support.

The launcher tube was 130cm long and was of 60 mm calibre, linked to a system of tanks, pistons and mobile breech (total weight 22 kg). mounted on 3-legged cradle, weighting 16 kg .. Initially developed as a pneumatic launcher of hand grenades, this mortar eventually received specific projectiles, with small wings screwed at the bottom of the cone. Additionally, each regiment was given a mixture of three 37 mm trench guns (with one going to each battalion), along with several trench mortars (notably, the Brandt pneumatic).

Constantinesco water and oil mortars George Constantinesco believed that, given the right circumstances, liquids could be compressed. In a set of experiments he demonstrated that it was not only possible to compress a liquid under very high pressure, but also to store the resultant energy and release it when required. Using this principle, he constructed silent,smokeless and flashless guns, including mortars and a cannon. The mortar worked by the expansion of water compressed to 2,000 atmospheres (about 30,000 psi.) by a hand pump. At this pressure the water would have been compressed to 70% of its original volume. The cannon was capable of throwing a 90 kg bomb over a distance of 1,400 metres with the energy derived from the expansion of highly compressed oil. Prototypes were built and proven workable.These experiments Constantinesco thought were sufficient to prove that liquids were compressible and also indicated the ballistic possibilities, comparable with explosive propellants for military use, but officialdom was yet to be convinced. By 1915 Constantinesco had taken out a whole range of British Patents on various aspects of wave transmission, including heat generation and flashless guns and submitted them to the War Office for consideration as to their use in the war effort. However they were viewed with considerable scepticism and suspicion, especially when it was suggested that wave power could be used to heat trenches on the Western Front, and as for the guns, their function relied on the compressibility of liquids, which was commonly thought to be impossible. As the whole concept of wave transmission relied largely on the compressibility of liquids, the validity of which had not yet percolated through to the Authorities, all the inventions were turned down out of hand as the "ravings of a mad Romanian!'' Constantinesco then turned his attention to using pneumatics for the synchronisation of aircraft mounted machine guns.

[Ian Riley]

Anybody able to give me clue as to the calibre of the De Breviare mortar (previous Post #3) with a patent at http://worldwide.espacenet.com/publicationDetails/biblio?CC=GB&NR=100408and references in the records of the Second Army Trench Mortar School at Berthen

• 27 May 1915: DE BREVIARE Trench Mortar arrived from 3^rd CORPS for experiments
  
• 22 November 1915: De Breviare Gun arrived
  
• 24 November 1915: Dummy rounds fired from De Breviare gun. 6^th Corps commander and other officers present
  
• 3 December 1915: Trials with De BREVIARE before experimental committee and a large number of staff officers.
  

Whilst I am here can anyone help me the abbreviation DA Fuze. Thjey are having trouble with fuzes on the 1.5" (OK I know its 1.5....) and the 2" mortars and through the second half of 1915 are trialling the "DA Fuze". Divisional Artillery? Director of Artillery? .... light bulb has just flickered in the head and I think I am going to answer my own question ... Delayed Action?

Ian

[nigelfe]

^{"Direct Action"}

[Ian Riley]

Thank you