Country of origin |
United States |
Entered service |
1962 |
Crew |
5 men |
Dimensions and weight |
Weight |
21 t |
Length |
6.1 m |
Width |
3.15
m |
Height |
3.27 m |
Armament |
Main gun |
105 mm |
Barrel length |
30 calibers |
Machine guns |
1 x 12.7 mm |
Projectile weight |
14.9 kg |
Maximum firing range |
11.2 km |
Maximum rate of fire |
4 rpm |
Elevation range |
- 6 to + 75 degrees |
Traverse range |
360 degrees |
Ammunition load |
Main gun |
86 rounds |
Machine guns |
500 rounds |
Mobility |
Engine |
General Motors 8V71T diesel |
Engine power |
425 hp |
Maximum road speed |
56 km/h |
Range |
386 km |
Maneuverability |
Gradient |
60% |
Side slope |
30% |
Vertical step |
0.53 m |
Trench |
1.8 m |
Fording |
1.1 m |
Fording (with preparation) |
Amphibious |
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The M108 was
first fielded in 1962, as a replacement for the troubled M52
self-propelled howitzer. It was developed from the T195
self-propelled gun testbed, which itself was later further-developed
into the 155 mm T196 six months later.
The M108 was intended to be the short-ranged component of a
new generation of US Army self-propelled artillery, alongside (from
shortest range to longest) the 155 mm
M109,
the 203 mm
M110, and the 175 mm
M107. Though unimpressive compared to
the M109, the range of the M108 filled a wide gap between the
minimum range of 155 mm self-propelled artillery, and 120 mm mortar
carriers.
Though effective in combat during the Vietnam war, the M108
was considered lacking in lethality compared to larger 155 mm
howitzers (despite the fact that 105 mm rounds are comparable in
payload to 120 mm mortar rounds, and the aforementioned range gap
between these and 155 mm shells), and it was gradually phased out of
service from the US military in the early 1970s. The M108s removed
from US service were gradually passed on to allies, and replaced by
additional M109s in US service.
The M108 has
been operated by USA, Belgium, Brazil, Spain Taiwan, Turkey. The
M108 fleets in the militaries of Belgium and USA have both been
retired, but as of 2010, this weapon continues to see service in
Brazil, Spain, Taiwan, and Turkey.
The M108's
main gun is a rifled 105 mm M103 howitzer, with a tube 30 calibers
long, fitted to an M139 mount. It fires a 14.9 kg projectile at 472
m/sec, can elevate and depress to +75 and -6 degrees respectively,
and has an effective range of 11.16 km. The M103 fires HE, WP,
smoke, and chemical rounds, and also the M67 HEAT round. It can also
fire all standard NATO 105 mm rounds, with the exception of
rocket-assisted munitions. A 12.7 mm
M2HB heavy machine gun is
usually fitted to the rooftop skate mount, providing the M108 with
some degree of protection against aircraft and enemy personnel. 87
105 mm rounds are carried, along with 600 12.7 mm machine gun
rounds.
The M108's aluminum armor provides sufficient protection from
blast overpressure, shell splinters, and small arms fire (up to
12.7 mm AP over the frontal arc), but it has no spall liners or NBC
system. Due to its lack of an NBC system, M108 crews must exercise
maximum caution when firing chemical rounds, as contamination by their own munitions could result from a headwind from the impact
area.
The chassis of the M108 is flat on all sides, and virtually
featureless. The chassis roof is long, with a shallow slope at the
front. The front of the hull has a flat, slightly-peaked glacis
plate, and a large, square door with right-side hinges is in the
center of the rear end. The driver's hatch is on the extreme
front-left, is square in shape, and hinged on the left side. The
90-degree hull sides overhang the tracks with a pronounced gap. The
turret is horseshoe-shaped, with a steeply-sloped face and sides,
and a 90-degree slope on the rear. On each side of the turret is a
small, square-shaped door. The turret roof has a small, circular
hatch at the extreme front-right, and a round cupola at the
rear-left, fitted with a skate mount for a machine gun. The main gun
is short, with a conspicuous cylindrical fume extractor behind the
muzzle, and a cylindrical mantlet.
The M108 has a crew of 5 men. The driver's position is in the
aforementioned location, while the section chief, gunner, and 2
cannoneers reside in the turret. Crew accommodations are austere,
and the M108 does not have an air conditioner or heater as standard
equipment.
The M108 is powered by a Detroit Diesel 8V71T diesel V8,
generating 425 hp at 2300 rpm, mated to an Allison XTG-411-2A
automatic transmission with 4 forward gears, and 2 reverse gears.
511 liters of fuel are carried, giving the M108 a maximum range of
386 km. With 425 hp driving 21 tonnes, the M108 has a power/weight
ratio of 20.32 hp/tonne, and a governed top speed of 56 km/h.
The M108's suspension is a standard torsion bar system, with
7 individually-sprung roadwheels, and a T136 or T137 track, both
with 79 shoes-per-track. The track is a "flat track" type, with no
return rollers; the drive sprocket is forward and idler rear.
Combined with the vehicle's weight, its track footprint gives the
M108 0.69 kg/cm² of ground pressure.
The M108 is
6.1 m long, 3.15 m wide, 3.27 m tall, has no gun overhang, and
weighs 21 tonnes. It can tackle a 60% gradient, a 30% side slope, a
0.53 m vertical obstacle, or a 1.8 m trench. It has 0.45 m of ground
clearance, and is amphibious with preparation.
The M108's unit cost is approximately $244 000, though it is
no longer offered. No information is available on the size of its
production, though several hundred are still in use today.
Variants
M109; the ubiquitous M109
self-propelled howitzer is basically an M108 with a bigger 155 mm
gun. There are many variants of the M109, which are too numerous to
cover here. Most of the US Army M108 howitzers were converted to the
M109 standard.
M992 FAASV; this is the primary ammunition resupply carrier
for the M109, which is developed from the same chassis as used for
the M108 and M109.
XM701; this attempt to develop an infantry fighting vehicle
for the US Army (as a contender for the MICV-65 requirement), and is
basically a hybrid of the M108/M109 chassis, and the M107/M110
chassis. This project was effectively a disaster, as the ultimate
product failed nearly all of its mission-critical design
requirements.
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Article by
BLACKTAIL
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