Admiral Sir Reginald Bacon’s



The pictures show the model 15" Howitzer part of the collection of the Society of Model and Experimental Engineers. It was made by Admiral Sir Reginald Bacon, President of the society, in 1922. He presented it to
the society during his time as president. There is an article about the weapon and the building of the model published in the Model Engineer September 7 1922.

The full size weapon was designed under his direction at a time when he was managing director of Coventry Ordnance Works. It was a response to a perceived need for a heavier weapon following a successful German attack on the Liege forts. At the time the largest Howitzer available to the British forces was 9.2" calibre. The design brief was for a weapon that could be moved rapidly and capable of being mounted and dismounted by man power and 125hp tractors for transport. 

The design incorporated some ingenious design features:

Each sub assembly was limited to 6 tons. To achieve this, the gun had to
be split into three components. The barrel, a jacket and the breech bush. The barrel was made from a steel tube. bored and rifled, wire wound with an external tubes over the winding. This outer tube was tapered and fitted into a jacket with a matching taper to give the required strength. This did not lock on firing as the natural elasticity of the metal was not exceeded allowing the jacket to provide additional strength during the act of firing but relaxing after the projectile Ieft the barrel.
Because of the force of the discharge the recoil required the gun to be mounted on a solid platform. Concrete was out of the question due to time and cost restraints. Instead an ingenious platform was designed to resist the horizontal and vertical forces at firing. A steel platform 20ft square in sections that could be handled by four men was designed. To prevent horizontal movement ‘spuds’ were welded under these sections. To provide stiffness the sections were joined by 13 I-beams transversely across the plates followed by six I-beams longitudinally. On these were mounted two cast steel castings to carry the gun.
The gun fired a High Explosive projectile weighing 1450lbs with a muzzle velocity of 1,117Ft/s a range of 10795 yards. The weapon was not a success and apart from the 12 in the original batch no more were made. These were not accepted by the Army but instead Churchill acquired them for the Royal Marine Artillery division of the Naval Brigade.
In the 90 years that the model has belonged to the Society it suffered some depredations and was badly in need of restoration. This was undertaken by the SMEE committee. Researching details of the gun's construction and design was unsuccessful. The Imperial War Museum and The Royal Arsenal Museum were unable to assist.

For details of how it worked some pictures available on the internet and a short film clip also from the internet were used to work out the way the gun was operated. It required the production of a new capstan for the elevation mechanism and a smaller one for the Breech lock. Details for these items were based on the pictures. The loading tray and crane had been badly twisted and at some time in the past they had been covered in a thick grey paint.

The principle of the loading system was surmised to be: the barrel was depressed to the horizontal; the breech is unlocked and swung clear; the loading tray was swung down to rest on the interrupted threads the breech locks into, a brass pad under the tray was discovered and presumed for this purpose; a round was picked up in a cradle by the crane and swung over the tray before being lowered into position; the projectile, weighing almost half a ton, was then rammed into the breech by a team of gunners hauling a wire rope and chain combination rigged to force it into the breech. This conjecture is supported by the pictures. The gunners operating the gun used side mounted platforms to reach the breech etc. These had been badly damaged over the years but have now been repaired and replaced.

To complete the work on the model various sizes chain were sourced to scale for the loading crane, and the chain hoist repaired. New legs were made for the tray in order for it to sit correctly for loading and new chains were made to limit its swing when not in use. As many of the original fastenings as possible were reused, with modem machine made items being used where the originals were missing or beyond use. The thick paint was removed and the items sprayed with a paint specially mixed for the job. Unfortunately, the firing mechanism is missing from the breech. As there is no design information available no attempt has been made to replace it. The platform has been repaired as necessary then cleaned.