The
13 pounder 9 cwt anti-aircraft gun became the standard mobile British anti-aircraft gun of the
World War IWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
era, especially in theatres outside Britain. 13 pounder referred to the weight of the shell, 9
cwtCentum weight or hundredweight is a unit of mass with two definitions: the Imperial hundredweight, equal to 51 kilograms, and the U.S...
referred to the weight of the barrel and breech (9 x 112 lb = 1008 lb), to differentiate it from other varieties of "13 pounder".
Earlier anti-aircraft guns based on
13 pounderThe Ordnance QF 13-pounder quick-firing field gun was the standard equipment of the British Royal Horse Artillery at the outbreak of World War I.-History:...
and
18 pounderThe Ordnance QF 18 pounder, or simply 18-pounder Gun, was the standard British Army field gun of the World War I era. It formed the backbone of the Royal Field Artillery during the war, and was produced in large numbers. It was also used by British and Commonwealth Forces in all the main theatres,...
guns proved unsatisfactory.
The
13 pounder 9 cwt anti-aircraft gun became the standard mobile British anti-aircraft gun of the
World War IWorld War I , also known as the First World War, the Great War, and the War to End All Wars, was a global military conflict which involved most of the world's great powers, assembled in two opposing alliances: the Triple Entente and the Triple Alliance...
era, especially in theatres outside Britain. 13 pounder referred to the weight of the shell, 9
cwtCentum weight or hundredweight is a unit of mass with two definitions: the Imperial hundredweight, equal to 51 kilograms, and the U.S...
referred to the weight of the barrel and breech (9 x 112 lb = 1008 lb), to differentiate it from other varieties of "13 pounder".
History
Earlier anti-aircraft guns based on
13 pounderThe Ordnance QF 13-pounder quick-firing field gun was the standard equipment of the British Royal Horse Artillery at the outbreak of World War I.-History:...
and
18 pounderThe Ordnance QF 18 pounder, or simply 18-pounder Gun, was the standard British Army field gun of the World War I era. It formed the backbone of the Royal Field Artillery during the war, and was produced in large numbers. It was also used by British and Commonwealth Forces in all the main theatres,...
guns proved unsatisfactory. This weapon combined an 18 pounder breech and barrel with a liner (sleeve) inserted to reduce the bore from to so that it could fire the slightly smaller 13 pounder shell but still use the larger cartridge and propellant charge of the 18 pounder resulting in a much higher velocity. A slight neck was introduced in the 18 pounder cartridge to hold the slightly narrower 13 pounder shell in place.
The initial Mk III mounting was based on the 13 pounder Mk II anti-aircraft mounting, but proved to be not strong enough for the extra power of the 18 pounder cartridge.
The Mk IV mounting which followed raised the height by and increased recoil from 24 to and hence relieved the strain on the mounting.
Several guns are known to have been mounted on 2-wheeled high-angle field carriages and deployed on the
Italian frontThe Italian campaign refers to a series of battles fought between the armies of Austria-Hungary and Italy, along with their allies, in northern Italy between 1915 and 1918. Italy hoped that by joining the countries of the Triple Entente against the Central Powers it would gain Cisalpine Tyrol ,...
. Hogg & Thurston state that they could theoretically be used as anti-aircraft guns, field guns or howitzers, but they were not officially introduced and may have been of an experimental nature. Routledge states that the carriage was improvised because some of 4th AA Group's guns had arrived in Italy without mountings.
Combat use
As World War I progressed, it was replaced in the home air defence of England (against German heavy bombers) by the more powerful
QF 3 inch 20 cwtThe QF 3 inch 20 cwt anti-aircraft gun became the standard anti-aircraft gun used in the home defence of England against German airships and bombers in World War I. It was also common on British warships in World War I and submarines in World War II...
gun, but continued in all other theatres. It was usually deployed mounted on medium lorries such as the
ThornycroftThornycroft was a United Kingdom-based vehicle manufacturer which built coaches, buses, and trucks from 1896 until 1977.-History:Thornycroft started out with steam vans and lorries. John Isaac Thornycroft, the naval engineer, built his first steam lorry in 1896...
Type J with a speed of 18 miles per hour, in sections of 2 guns.
On the Western Front they were typically used to protect troop columns, airfields, bases, supply dumps and observation balloons.
As important as the raw performance of the gun itself was the new technology being developed to allow fast calculation of aircraft height and predict where it would be when the shell arrived near it. Modern aircraft could fly at over 100 miles per hour and to 20,000 ft (much lower over the battlefield) by 1918, which made the old reliable artillery shooting techniques obsolete. The shell took 10.1 seconds to reach fired at 25° above horizontal, 15.5 seconds to reach at 40°, 22.1 seconds to reach at 55°. Hence the aircraft position had be calculated 10 - 22 seconds in advance and fuzes needed to be set to explode at the correct height.
By the end of World War I, a 13 pounder AA Section was accompanied by 2 Wilson-Dalby Trackers with a rudimentary electronic computer to provide tachymetric prediction, a UB2 rangefinder, a Height/Fuze Indicator (HFI) and an Identification telescope. German fighters countered by attacking at low level - a few hundred feet. AA guns would continue to fire but the shells would then explode over the heads of those they were defending. But it brought attacking aircraft within range of defensive machine guns. Few aircraft were actually directly shot down, each requiring an average 4,000 - 4,500 shells, but guns were often employed in aerial barrages to deny an airspace to aircraft rather than to simply shoot down individually targeted aircraft. Brigadier Routledge notes that "in the BEF [i.e. on the Western Front] stress was laid on long-range deterrent fire; indeed in Fourth Army this was the BRA's stated policy. 'Kills' were therefore less common. Moreover, gun and fighter zones were not separated, as in Britain, and this made set plans for action less workable".
Routledge further comments that in World War I British cooperation between infantry and anti-aircraft sections was generally rudimentary. However, he points out a successful integration in the Allied advance on the Piave in Italy in late 1918, where S and V Batteries of 4th AA group used their 13 pdr 9 cwt guns to provide mobile air and ground fire in close support of infantry. This tactic later became common in World War II.
At the end of World War I, a total of 306 were in service worldwide, 232 of these on the
Western FrontFollowing the outbreak of World War I in 1914, the German army opened the Western Front by first invading Luxembourg and Belgium, then gaining military control of important industrial regions in France. The tide of the advance was dramatically turned with the Battle of the Marne...
(out of a total 348 AA guns there).
Performance
The following table compares the gun's performance with the other British WWI anti-aircraft guns:-
| Gun |
muzzle velocity (ft/s) |
Shell (lb) |
|
|
| Max. height (ft) |
QF 13 pounder Mk IIIThe Ordnance QF 13 pounder Mk III anti-aircraft gun, also known as 13 pounder 6 cwt, was an early British improvisation in World War I to adapt the 13 pounder field gun to anti-aircraft use...
|
1600 |
12.5 |
? |
? |
? |
17,000 |
| QF 13 pounder 9 cwt |
1990 |
12.5 |
10.1 |
15.5 |
22.1 |
19,000 |
QF 12 pdr 12 cwtThe 12 pounder 12 cwt anti-aircraft gun was borrowed for AA use from the QF 12 pounder 12 cwt coast defence gun with the addition of a modified cradle for higher elevation, a retaining catch for the cartridge, and an additional spring recuperator above the barrel and high-angle sights. Writers...
|
2200 |
12.5 |
9.1 |
14.1 |
19.1 |
20,000 |
QF 3 inch 20 cwtThe QF 3 inch 20 cwt anti-aircraft gun became the standard anti-aircraft gun used in the home defence of England against German airships and bombers in World War I. It was also common on British warships in World War I and submarines in World War II...
1914 |
2500 |
12.5 |
8.3 |
12.6 |
16.3 |
23,500 |
QF 3 inch 20 cwtThe QF 3 inch 20 cwt anti-aircraft gun became the standard anti-aircraft gun used in the home defence of England against German airships and bombers in World War I. It was also common on British warships in World War I and submarines in World War II...
1916 |
2000 |
16 |
9.2 |
13.7 |
18.8 |
22,000 |
| QF 4 inch Mk V WWI The QF 4 inch Mk V gun was a Royal Navy gun of World War I which was adapted on HA mountings to the heavy anti-aircraft role both at sea and on land, and was also used as a coast defence gun.-Royal Navy service:...
|
2350 |
31 (3 c.r.h.) |
4.4 |
9.6 |
12.3 |
28,750 |
| QF 4 inch Mk V WWII The QF 4 inch Mk V gun was a Royal Navy gun of World War I which was adapted on HA mountings to the heavy anti-aircraft role both at sea and on land, and was also used as a coast defence gun.-Royal Navy service:...
|
2350 |
31 (4.38/6 c.r.h.) |
? |
? |
? |
31,000 |
See also
Surviving examples