The first development of Anti-Aircraft Artillery
The Great War was the first in which heavier-than-air aircraft played an important role. While the central role of the air forces was reconnaissance for the purposes of assisting the artillery, tactical and strategic bombing, together with ground support and strafing, grew in importance as components of the air approach of all sides. Shooting down enemy aircraft (or at least frightening them off) naturally followed as an important aspect of defence. Firing at a moving airborne target is most difficult, but the basics of weaponry, gunnery and command all developed fast during the war. This section of the Long, Long Trail explains how.
No army organisation existed prior to August 1914 for anti-aircraft purposes, although the Admiralty had established a development programme that had led to the design of 3-inch and 4-inch high angle QF (quick firing) guns for the Royal Navy. On the outbreak of war, the Admiralty assumed responsibility for anti-aircraft defence of London and established an AA Corps of the Royal Naval Volunteer Reserve. The War Office was made responsible for defence of important locations such as munitions factories, and set up a small staff organisation to consider how to proceed.
1914: RNVR AA and the defence of London
The RNVR units set up guns on the tops of key buildings in Whitehall and at the Thames docks, as well as near facilities at Woolwich (Arsenal), Waltham (Ordnance Factory) and Chattenden on the Medway. In all 30 guns were sited. 12 acetylene-lit searchlights provided night illumination against the threatened Zeppelin raiders. Ordnance stores were combed for any other useful guns, and some 58 of various ancient types were installed to cover naval installations at – for example – Dover, Harwich, Liverpool and the Tyne and Humber.
1914: the army develops AA Sections
The new War Office staff proposed to raise a number of AA Sections, which would officially be Companies of the Royal Garrison Artillery. The target was to raise one Section for each of the Divisions that were going to France. In the event, this was not fully achieved until 1916. Some men were posted from all three branches of the Royal Artillery, but they were too few and new recruits would be needed to properly establish these units. In addition, they would need motorised transport to be provided by the Army Service Corps. Six Sections were formed by November 1914, each consisting of (in theory, two but in practice one) 1-pounder (1.46 inch) Vickers Pom-Pom guns, each under a Captain. The first units arrived in France in September 1914. They soon discovered that the 1-pounders, not having been designed for the application, were of limited value in an anti-aircraft role.
1914: first AA success in France
On 23 September 1914, Lieutenant O. Hogg and his gun team of No. 2 AA Section, then with III Corps, shot down an enemy aircraft after firing 75 rounds at it.
1915: the search for better guns and equipment
The 1-pounder Vickers Pom-Pom guns proved of limited value, and work soon began on experiments to adapt the existing 13- and 18-pounder field guns for AA use. One version, the Mark 3 QF 13-pounder, went into service in 1915 and although it was far from perfect remained in service throughout the war. It was mounted on a lorry chassis. A later version used the 18-pounder but with a lining inside the barrel that allowed it to fire the smaller 13-pounder shells. This became the standard AA gun in France, and was known as the 13-pounder 9-cwt (hundredweight). Both types fired a shrapnel shell with a time fuze; the larger gun could fire to 19000 feet. In addition, the French 75mm was also adapted for AA use and some 40 went into service. A number were also added to the RNVR London defences.
1915: expansion and reorganisation
As it was becoming ever more apparent that air observation, bombing and fighting was an important aspect of this war, the demand for AA increased. GHQ in France ordered that not only should there be one Section per Division, but another 15 to cover the lines of communication. In July 1915, two Searchlight Sections (organised by the Royal Engineers) were stationed in Saint-Omer. By August 1915, there were in all 13 Sections in France. In October 1915, all existing guns were grouped into four-gun Batteries denoted by letters of the alphabet, and in the following month a specialist air gunnery officer was attached to the staff of the Major-General Royal Artillery at each Army HQ. At home, air defences were added to cover the vital manufacturing centres of Birmingham, Coventry and Sheffield.
1916: expansion continues; another reorganisation
By May 1916, 50th Field Searchlight Company RE and 5 more AA Sections had arrived in France. On the night of 20/21 June 1916, enemy aircraft successfully attacked and bombed the large British ammunition depot at Audruicq. By July, 70 of the total 113 AA guns in the field were of the 13-pounder 9-cwt type. Night bombing of the camps and roads behind the lines became a feature of the Somme campaign. In November 1916, the existing Battery organisation was abolished and 3 or 4 Sections were allotted to each Corps. Each Army HQ now had an AA Group HQ staff. At the front, individual AA regions were defined, each having an AA Defence Commander who would oversee a number of Sections plus various searchlight and machine gun crews: this was called an AA Group. Each of the five British Armies had a Group, and one large one – 19 Sections – covered the Lines of Communication. The first of a new type of gun, the 3-inch 20-cwt arrived. By the end of the year there were 91 AA Sections of the RGA in France, of which two were Canadian. 10 were equipped with the 3-inch gun. In addition there were by now 22 Searchlight Sections of the RE. An AA Experimental Section was established at home, to accelerate development of range finders and other equipment.
1916: what comprised an AA Section?
The Section consisted of 43 men in total: 2 officers, two gun detachments of 12 men each (of which 1 in each was a Driver of the ASC), 2 telephonists, 1 linesman, 4 height finders, 4 Wilson-Dalby Detector Operators, 2 Height and Fuze Indicator men, 1 Order Board Setter, 1 Lookout man (Air sentry), 1 orderly and 1 cook. All RGA unless indicated.
1916: total British AA strength
By the last quarter of 1916, there were in all 183 Sections consisting of 367 guns in England. In France, there were 74 Sections, made up of 147 guns. There were also 3 Sections in Egypt, 6 in Salonika and 1 in Mesopotamia.
The preparations for the Battle of Cambrai in November 1917 were novel in many respects. For the first time, an air defence plan was an integral part of the overall scheme of attack. 7 AA Batteries were allotted to the front that was to be assaulted, and their covering fire swept up to 3500 yards ahead of the British line. 2 gun sctions were made ready to follow up the advance.
1918: command properly established
In accordance with a review that took place and reported in late December 1917, the AA Sections were placed under command of an Assistant Director AA at GHQ. The first was Lieutenant Colonel N. Webber, a Royal Engineer. He was replaced on 30 March 1918 by C. Evans, an artilleryman who was more senior and who was appointed Brigadier General Director AA. He was succeeded on 18 July 1918 by Colonel V. Napier.
How effective was British AA fire in the Great War?
With guns that had not been designed for the purpose and appropriate equipment late in being developed, the AA was perhaps more of a deterrent than an actually effective weapon. The complexities of deflection firing, weather conditions, target fixing, variable gun condition, etc made for a very difficult operation. Training was all too brief, and methods experimental. Most of the gun Sections arrived in the field of battle without having fired a live shot. One source says that for example, in the busy week ending 27 April 1918, a total of 10 enemy aircraft were shot down and another 5 damaged, of a total of 2039 engaged.