An anti-aircraft vehicle, also known as a self-propelled anti-aircraft gun or
self-propelled air defense system, is a mobile vehicle with a dedicated
anti-aircraft capability. The Russian equivalent of SPAAG is ZSU, for
zenitnaya samokhodnaya ustanovka,. Specific weapon systems used include
machine guns, autocannons, larger guns, or missiles, and some mount both guns
and longer-ranged missiles. Platforms used include both trucks and heavier
combat vehicles such as APCs and tanks, which add protection from aircraft,
artillery, and small arms fire for front line deployment.
Anti-aircraft guns are usually mounted in a quickly-traversing turret with a
high rate of elevation, for tracking fast-moving aircraft. They are often in
dual or quadruple mounts, allowing a high rate of fire. Today, missiles have
largely supplanted anti-aircraft guns. History
= World War I = Anti-aircraft machine guns have long
been mounted on trucks, and these were quite common during World War I. A
predecessor of the WW2 German "88" anti-aircraft gun, the WWI German 77 mm
anti-aircraft gun, was truck-mounted and used to great effect against British
tanks. The British QF 3 inch 20 cwt was mounted
on trucks for use on the Western Front. = Inter-war period =
Between the two World Wars the United Kingdom developed the Birch gun, a
general purpose artillery piece on an armoured tracked chassis capable of
maintaining formation with their current tanks. The gun could be elevated for
anti-aircraft use. Vickers Armstrong also developed a SPAAG
based on the chassis of the Mk.E 6-ton light tank/Dragon Medium Mark IV
tractor, mounting a Vickers QF-1 "Pom-Pom" gun of 40 mm. About 26 were
sold to Siam and saw action as Infantry support guns and AA guns during the
Franco-Thai war along with 30 Vickers Mk.E Type B 6-ton tanks. This was
probably the first tracked SPAAG manufactured in series. Later the
British also developed a version of the Mk.VI light tank armed with 4 machine
guns that was known as Light Tank AA Mk.I. And also a twin 15 mm version
based on the Light Tank Mk.V was built. Among early pre-war pioneers of
self-propelled AA guns were the Germans. By the time of the war, they fielded the
SdKfz 10/4 and 6/2, cargo halftracks mounting single 20 mm or 37 mm AA guns.
Later in the war similar German halftracks mounted quadruple 20 mm
weapons. = World War II =
Larger guns followed on larger trucks, but these mountings generally required
off-truck setup in order to unlimber the stabilizing legs these guns needed. One
exception to this rule was the Italian Cannone da 90/53 which was highly
effective when mounted on trucks, a fit known as the "autocannoni da 90/53". The
90/53 was a feared weapon, notably in the anti-tank role, but only a few
hundred had been produced by the time of the armistice in 1943.
Other nations tended to work on truck chassis. Starting in 1941, the British
developed the "en portee" method of mounting an anti-tank gun on a truck.
This was to prevent the weapon from being damaged by long-distance towing
across rough, stony deserts, and it was intended only to be a carrying method,
with the gun unloaded for firing. However, crews tended to fire their
weapons from their vehicles for the mobility this method provided, with
consequent casualties. This undoubtedly inspired their Morris C9/B, a Bofors 40
mm AA gun mounted on a chassis derived from the Morris "Quad" Field Artillery
Tractor truck. Similar types, based on 3-ton lorries, were produced in Britain,
Canada and Australia, and together formed the most numerous self-propelled
AA guns in British service. The U.S. Army brought truck-towed Bofors
40 mm AA guns along with truck-mounted units fitted with mechanized turrets
when they sailed, first for Great Britain and then onto France. The
turrets carried four .50 inch machine guns, which were designed to be adjusted
to converge at the single point where enemy aircraft were expected to appear
at low altitude in conduction of strafing runs directed at large infantry
and field artillery units. Interest in mobile AA turned to heavier
vehicles with the mass and stability needed to easily train weapons of all
sizes. Probably the desire, particularly in German service, for anti-aircraft
vehicles to be armoured for their own protection also assisted this trend.
The concept of an armored SPAAG was pioneered by Hungary during World War II
Hungary by producing the 40M Nimrod based on the Luftvärnskanonvagn L-62
Anti II license acquired from Sweden. Germany followed later with their
"Flakpanzer" series. German World War II SPAAGs include the Möbelwagen,
Wirbelwind, Ostwind and Kugelblitz. Other forces followed with designs of
their own, notably the American M16 created by mounting quadruple M2HB
Browning machine guns on a M3 Half-track.
The British developed their own SPAAGs throughout the war mounting multiple
machine guns and light cannon on various tank and armoured car chassis and by
1943, the Crusader AA tanks, which mounted the Bofors 40 mm gun or
two-three Oerlikon 20 mm cannon. Although used during the Normandy
landings, by that point German aircraft were contained by the Allies own air
forces and they were largely unneeded. = Cold War and later =
The introduction of jet engines and the subsequent rough doubling of aircraft
speeds greatly reduced the effectiveness of the SPAAG against attack aircraft. A
typical SPAAG round might have a muzzle velocity on the order of 1,000 metres
per second and might take as long as two to three seconds to reach a target at
its maximum range. An aircraft flying at 1,000 kilometres per hour is moving at a
rate of about 280 metres per second. This means the aircraft will have moved
hundreds of meters during the flight time of the shells, greatly complicating
the aiming problem to the point where close passes were essentially impossible
to aim using manual gunsights. This speed also allowed the aircraft to
rapidly fly out of range of the guns; even if the aircraft passes directly
over the SPAAG, it would be within its firing radius for under 30 seconds.
SPAAG development continued through the early 1950s with ever-larger guns,
improving the range and allowing the engagement to take place at longer
distances where the crossing angle was smaller and aiming was easier. Examples
including the 40 mm U.S. M42 Duster and the 57 mm Soviet ZSU-57-2. However, both
were essentially obsolete before they entered service, and found employment
solely in the ground-support role. The M42 was introduced to the Vietnam War to
counter an expected North Vietnamese air offensive, but when this failed to
materialize it was used as an effective direct-fire weapon. The ZSU-57 found
similar use in the Yugoslav Wars, where its high-angle fire was useful in the
mountainous terrain. By the late 1950s the US Army had given
up on the SPAAG concept, considering all gun-based weapons to be useless against
modern aircraft. This belief was generally held by many forces, and the
anti-aircraft role turned almost exclusively to missile systems. The
Soviet Union remained an outlier, beginning development of a new SPAAG in
1957, which emerged as the ZSU-23-4 in 1965. This system included
search-and-track radars, fire control, and automatic gun-laying, greatly
increasing its effectiveness against modern targets. The ZSU-23 proved very
effective when used in concert with SAMs; the presence of SAMs forced
aircraft to fly low to avoid their radars, placing them within range of the
ZSUs. The success of the ZSU-23 led to a
resurgence of SPAAG development. This was also prompted by the introduction of
attack helicopters in the 1970s, which could hide behind terrain and then "pop
up" for an attack lasting only a few tens of seconds; missiles were
ineffective at low altitudes, while the helicopters would often be within range
of the guns for a rapid counterattack. Notable among these later systems is the
German Gepard, the first western SPAAG to offer performance equal to or better
than the ZSU. This system was widely copied in various NATO forces. US
attempts to introduce a new SPAAG were doomed to become a series of
half-measures and dismal failures; the failure of the missile-based MIM-46
Mauler led to the introduction of the optically-aimed M163 VADS of very short
range, and the long-delayed and finally cancelled M247 Sergeant York which
offered almost laughable performance in testing, unable to hit even stationary
targets. SPAAG development continues, with many
modern examples often combining both guns and short-range missiles. Examples
include the Soviet/Russian Tunguska-M1, which supplanted the ZSU-23 in service,
newer versions of the Gepard, and the British Marksman turret, which can be
used on a wide variety of platforms. See also
Man-portable air-defense system Flakpanzer, a collective term for German
anti-aircraft tanks, particularly those used in World War II.
List of anti-aircraft guns References