The Allies AAA Guns of the Great War

By Raul Colon
October 23rd 2008
Email:rcolonfrias@yahoo.com

Pierce-Arrow Anti-Aircraft Armoured Car

The concept of an Anti Aircraft Artillery guns was not even to the imagination of field commanders in the early part of the Twenty Century. Aviation was a new field of battle at that time; a much misunderstood one too. But, as with any new human-developed field, there were countermeasures being developed almost at the same time that the first few planes took to the air. As with the case with many war-related innovations, Germany took the lead in this new area. Between 1908 and 09, Germany demonstrated that an effective AAA system could be achieved with the available weapon systems. The first rudimentary “Balloon Guns”, as they were then referred to; were developed by either the Krupp Corporation or the Rheinmetall Group. These pieces were basically a field gun modified to fire at a higher angle mounted on a truck. At the same time, Germany began to encircle its biggest cities with field artillery pieces turned through 360 degrees. These pieces were placed on static angles mounts which enabled them to fire at a higher angle. At the time of the start of the Great War, there were so few airplanes available to either side that the development of AAA systems were relegated to the bottom of every nation’s military budget. In those days, weapons budgetary assignments usually went to the Army and Navy. In the case of an Army for example, those funds were used to develop advanced armoured vehicles, more powerful field and machine guns as well as heavy mortars mainly designed for siege operations.

In August 1914, the British Expeditionary Force (BEF) had only a handful of rudimentary AAA guns on towed mounts. The French were even less prepared with only two modified De Dion Bouton cars fitted with high angled field guns. The main British AAA gun of the war was the 13th Pounder. The system was a combination of a 13th pounder light field gun mounted on Thornycroft J-type automobile which was one of the most strange-looking vehicles of the entire war. The J-types were fitted with stabilizers and screw jacks in order to prevent the guns’ recoil from overturning the vehicle. Usually, the British would deploy two of these systems accompanied by two other vehicles for the crew, range finding equipment and ammunition. The first of these 13 Pounders began to appear on the Western Front during the summer of 1915. Meanwhile, the French began to use their famous 75 mm field gun in an anti aircraft role, mostly because the gun’s high firing rate. The 75 mm AAA concept was a very simple one. The guns were mounted on top of a De Dion automobile fitted with several stabilizers for recoil absorption.

British 13th Pounder Gun French 75 mm AAA Gun

Shell Weight 13lb 15.8lb
Gun Weight 2150lb 8800lb
Elevation +80 degrees +70 degrees
Vertical Range 13100’ 15500’
Muzzle Velocity 1700’/second 1740’/second

The French 75 mm gun was extensively used on all fronts by the Allies. In fact, when the first daylight bombings of London commenced in the summer of 1915, the British acquired some of these weapons in an effort to bolster their capital city’s air defences.

The main problem facing AAA operators was the targeting of, a moving three dimensional object. At the beginning, the gun was fired directly at the aircraft but by the time the shell arrived at the right altitude, the target would had moved on. Gunners began to mitigate this problem by mounting complex sights on all of their weapons. Unfortunately for the gunners, this only duplicated the batteries’s efforts. It was then found simple enough to fit one, centralized sight positioned in the middle of a battery of guns. Once the crew had managed the data related to the height, range and speed of an incoming object; this was passed on to individual targeting gunners who would calibrate its guns towards the target.

By June 1916 Britain had 271 anti-aircraft guns and 258 searchlights in position to defend possible German targets. The Air Ministry believed that they required at least 487 anti-aircraft guns to provide the country with a reasonable defence against German bombing missions. However, even by 1918, Britain only had 349 anti-aircraft guns and although they occasionally brought down German aircraft they were widely viewed as being inadequate.

It is almost impossible to achieve a reliable figure of the number of downed aircraft by those rudimentary AAA system, but is fair to say the number was a very low one. However, conclusive evidence has shown that AAA-generated fire did alter German reconnaissance patters in the later stages of the war.