here's an recent article on the Terrex:
ST Kinetics' new 8x8 Terrex AV81 has been designed to its
requirements by Timoney Technology of County Meath, Ireland. In
addition to designing its prototype, Timoney was also responsible
for the welding of its hull, assembling it and carrying out
preliminary automotive trials prior to its unveiling at the DSEi
exhibition in London in September 2001 (see IDR 11/2001,
p16).
The design and construction of the prototype were accomplished in a
remarkably short period of 18 months. This stands in striking
contrast to the protracted gestation of some other contemporary 8x8
armored vehicles, and can be attributed in part to the experience
Timoney acquired in the design of similar armored vehicles and to
the use of Timoney's previously developed axle and suspension
modules.
Timoney's experience goes back to the mid-1970s when it built a
small batch of 4x4 armored carriers for the Irish Army. The report
on this by IDR (see IDR 4/1975, pp578-580) attracted the attention
of the Belgian authorities and 146 Timoney 4x4 armored carriers
were subsequently built in Belgium under license as the BDX. By
1990, Timoney had designed and built a heavier 6x6 armored carrier,
which led to similar CM 31 prototypes for the Republic of China
(Taiwan) as well as designing other vehicles and the chassis of the
P.23 8x8 Crash Fire Rescue vehicle, 250 of which were built for the
US Air Force (see IDR 8/1990, pp883-885). CM 31 is now being
developed in Taiwan into the 8x8 CM 32, and its design foreshadowed
in some respects that of Terrex AV81.
All the vehicles designed by Timoney have incorporated its
integrated axle-cum-suspension modules, which have been refined
progressively over a period of more than 20 years. As a result they
are available, fully developed, for Terrex AV81, providing it with
the advantages of a proven independent suspension and axle design.
Its effectiveness is attested by its adoption also by the
manufacturers of other vehicles, who wanted to benefit from the
advantages of independent suspension instead of following the
common practice of using rigid-beam axle truck suspensions but did
not want to invest time and money in the development of their own
systems. Examples of this include Volvo military trucks and the 4x4
M1117 Armored Security Vehicle produced by Textron Marine and Land
Systems for the US Military Police. Another vehicle currently using
Timoney axle-suspension modules is the Bushmaster Infantry Mobility
Vehicle designed by Timoney and built by ADI for the Australian
Army.
The independent suspension, which forms part of the modules, is of
the double wishbone type with a single coil spring and a concentric
telescopic damper acting on the lower wishbone. In addition to the
suspension elements each module includes a differential unit,
universally jointed half-shafts and hub-mounted disc brakes
actuated by an anti-lock braking system. The wheels which go with
this are fitted with large diameter 395/85 R20 tires connected to a
central tire-inflation system which allows them to be deflated on
the move to reduce the ground pressure for the crossing of soft
ground.
Four modules support the hull, which is welded from high-hardness
steel plates thick enough to provide in its basic form all-round
protection against 7.62mm x 51-ball ammunition. However, higher
levels of protection up to 14.5mm armor-piercing bullets are to be
provided by add-on armor. As ST Kinetics' Bionix has already been
fitted with the MEXAS ceramic tile armor produced in Germany by
IBD, this is also likely to be fitted to Terrex AV81.
In keeping with the importance currently attached to protection
against mines, considerable attention has been paid to it in the
design of the hull. One of the results of this is that the hull has
a double floor, with its outer layer being V-shaped to help deflect
mine blast, and there is a blast-deflector plate under the drive
line. In designing the hull against mines, Timoney benefited from
its experience in Australia with the Bushmaster, which successfully
competed with a vehicle from South Africa, the country that has led
in the design of mine-resistant vehicles. In consequence Terrex
AV81 is claimed to be able to withstand the explosion of a 10-12kg
mine anywhere underneath it.
The hull has an internal volume of no less than 12.2m3, which is
more than sufficient to meet the contemporary demands for capacity.
This enables it, among other capabilities, to accommodate up to 12
persons in addition to a crew of two when Terrex AV81 is used as a
personnel carrier. In spite of this, the overall dimensions of
Terrex AV81 are somewhat smaller than those of other 8x8 armored
vehicles currently being developed, the length being 6.8m, width
2.7m and height to the top of the turret roof 2.1m. One of the
benefits of its relatively compact dimensions and an unladen weight
of only 13,000kg is that Terrex AV81 is transportable in C-130
aircraft.
An interesting feature of the hull design is that its roof is
removable to ease modifications required by different weapon
installations or by demands for even more space - in particular
headroom - for command-post and ambulance versions. The ability to
remove the roof does not affect the integrity of the hull's
monocoque structure, and represents a more effective approach to
the problem of adapting a vehicle to different roles than the
replacement of most of its hull by a separate, exchangeable
'mission module'. The latter has been adopted for some vehicles
currently being developed, but is less efficient structurally and
makes them heavier as well as more complicated and more costly to
build.
As in other 8x8 armored vehicles, the front part of the hull houses
the engine compartment. Alongside it is the driver's station, which
is to be fitted with a novel type of cupola that is currently the
subject of a patent application. The cupola is rotatable and has a
'bulletproof' windscreen on one side of it and a face of armor
surmounted by periscopes on the other. The driver does not
therefore have to drive 'head out' when he wants a better view of
the road - exposing himself in the process to the weather and minor
threats - but can look through the windscreen and stay under cover
at all times, rotating the cupola 180º according to the conditions
in which his vehicle operates.
As the rotatable driver's cupola was not installed on the
prototype, the latter was fitted instead with the same arrangement
of three fixed periscopes as the Bionix.
The engine which powers Terrex AV81 is a Caterpillar C 9 6-cylinder
turbocharged diesel, developing 420hp (313kW) at 2,200rpm and
coupled to an Allison HD 4560P automatic transmission with six
forward and one reverse gear. The drive from the transmission is
through a single-speed drop box and a single-speed transfer case at
the second axle unit and then to the front axle rearwards to the
third and fourth axles, all eight wheels being permanently driven.
The whole drive train as well as the engine is designed to give the
vehicle a maximum road speed of 120km/h.
When lightly laden the vehicle has sufficient buoyancy to float
without aids, but these are being developed to enable it to operate
in water even when its gross weight is at its maximum of 24,000kg.
In water it can propel itself by means of two water-jet propulsion
units made by Ultra Dynamics. These are hydraulically driven and
one is mounted on either side of the rear of the hull.
At DSEi, Terrex AV81 was exhibited with an ST Kinetics 40mm
automatic grenade launcher and a 7.62mm machine gun, both mounted
externally and remotely operated from within the hull. Possible
alternative weapon installations include a 25mm automatic cannon in
an ST Kinetic two-person turret, which is already used on the
Bionix, and low recoil-force 105mm tank gun.
The prototype has now been shipped to Singapore where decisions are
to be taken about the second prototype.
