Home' Defence Technology Review : DTR OCT 2015 Contents 39
DEFENCE TECHNOLOGY REVIEW | ISSUE 14 | OCT 2015
The CRV will also be fitted with anti-skid braking systems.
The ASLAV has none. These systems avoid loss of control when
braking in marginal conditions and increase the speed with
which drivers can tackle certain routes and conditions. This
improvement confers many advantages including survivability.
Driver comfort will also be higher in CRV. Comfort affects
mobility too and is often overlooked. If an 8x8 organisation
is ordered to march 1,000km, if the driver is protected from
airborne debris, temperature extremes and the elements, it can
make a big difference to their ability to fight when they reach
their destination. ASLAV does not offer much protection to the
driver unless they are closed down and driving with periscopes.
In contrast, most CRV will seal the driver from the outside,
provide the same level of visibility as when opened up and provide
protection from the elements. Sealing the driver’s compartment
will also allow more effective operation of the vehicle’s air-
conditioning and heating systems for the other crew and
passengers. This improves their ability to fight when they arrive at
The second category includes those instances in which the
mobility of CRV and ASLAV will be equivalent or where the
difference will not affect capability.
There are numerous international conventions which almost all
8x8 vehicles now meet, regardless of their size and weight. The 60
per cent (31°) forward slope and the 30 per cent (17°) side slope are
two examples. Even though the CRV will be higher than ASLAV
– both to the top of the hull and turret roof – it will be very dense
around the hull floor and sponsons (therefore lowering centre-of-
gravity) and so the difference in side slope mobility will be minor.
The CRV will also have a similar power-to-weight (PWR)
ratio as ASLAV. For a long time, the international convention
for armoured vehicles has been about 20hp/tonne. A higher
PWR is necessary not just for climbing steep gradients at
higher speeds; it also reduces the time required to move from
one stationary position to another. This improves survivability.
It also helps wheeled vehicles keep up with tracked vehicles
such as tanks on rough terrain.
Another international convention is turning circle. Not being
able to turn around quickly can leave an 8x8 vehicle very exposed
in an urban environment. The convention for turning circle
diameter is somewhere between 15m and 20m. As 8x8 vehicles
have grown longer and wider, designers have introduced steering
and braking techniques to keep turning circles in the 15-20m
range. The CRV will have either fourth axle steering or skid
steering to achieve a turning circle comparable with ASLAV.
ASLAV has neither.
There are many other areas in which the mobility of CRV and
ASLAV are expected to be equivalent. For example, like ASLAV,
the CRV will be fitted with run-flat tyres. The distance and speed
that a vehicle with deflated tyres can drive without the tyres
catching fire or disintegrating are defined under the Finabel
standards. One of the performance standards demands that with
all four tyres on one side deflated the vehicle is to be capable
of driving a distance of 40km at a speed of 40km/h. CRV will
perform at least as well as ASLAV under these conditions.
CRV will also be fitted with a central tyre inflation system
(CTIS). A CTIS typically has four pressure settings which are
selected by the crew according to conditions. Tyre pressures can
be changed from one setting to another whilst the vehicle is on
the move. The system will maintain tyre pressure in the event
of small leaks and isolate the tyre in the event of a major leak.
Reducing tyre pressures will reduce sinkage in most ground
conditions. CRV will perform as well as ASLAV under these
There are also aspects of CRV mobility that will be inferior
to ASLAV but will have little or no practical effect on overall
capability. A simple example is air transportability in the C-17A
Globemaster III heavy airlifter. Like the ASLAV, the CRV will
easily fit on the C-17 and allow the aircraft to reach maximum
range. It is true that the C-17A will carry more ASLAVs than
LEFT: Even tracked vehicles
are not immune to falling
foul of difficult terrain. Here,
a German Army Marder 1A5
infantry fighting vehicle is in
need of extraction from the
banks of the Kunduz River in
RIGHT: The soft soil mobility
of the current generation of
highly protected wheeled
AFVs is maintained by a
combination of larger tyres,
drivelines and good PWR.
CRVs but the CRV will deliver more combat power in proportion.
The same applies to the Canberra-class landing helicopter
dock (LHD) amphibious assault ships where the slightly larger
footprint of the CRV will see a few less accommodated on the
tank deck than ASLAV. Whereas the LHD’s light vehicle deck
can carry a dozen or more ASLAVs, it is not intended to support
vehicles the weight of CRV. The LHD Landing Craft (LLC) can
carry two ASLAV and will carry one CRV.
One obvious area in which CRV mobility will be inferior to
ASLAV is amphibious capability. In its original form, ASLAV
was an excellent swimmer. Its swim weight was only marginally
lower than its combat weight. Amphibious operations were a
realistic prospect. However, when ASLAV’s weight was increased,
the gap between swim weight and combat weight increased and
amphibious operations became less practical because more weight
had to be shed before the vehicle could swim.
In theory, a number of CRV contenders are amphibious because
they are based on lighter amphibious versions of the baseline
vehicle. However, with the addition of a medium-calibre turret
and very high levels of protection (read: weight), these vehicles
will not be able to swim anywhere near their combat weights or
swim at all. Buoyancy aids akin to a life jacket may be available
for these vehicles. The Australian commander would then have
three options: to swim with buoyancy aids and discard them, to
swim at a much lower weight (meaning fewer passengers, less fuel
and less ammunition), or be carried from the LHD to the beach
by the LLC.
For amphibious vehicles, the overall design is permanently
compromised by the accommodation of amphibious steering and
propulsion systems. It appears that the Land 400 program office
understood this compromise prior to tender release, which might
explain why there is no requirement for amphibious capability.
Another respect in which CRV will have inferior mobility
results from increased width and height (additional length will
be less important). The width of ASLAV and other 8x8s of its era
was determined by the interior width of C-130 Hercules aircraft.
This was a driving factor in the requirements of many 8x8
customers worldwide. With the wars in Iraq and Afghanistan, the
requirement for higher levels of protection and the increasing use
of C-17 and C-5 Galaxy aircraft as well as civilian freighters such
as the Boeing 747, this requirement was relaxed.
The width of the current generation of 8x8 vehicles is now
determined by the unescorted European road vehicle width (3m).
As a result, the CRV will be a shade less than 3m in width in basic
configuration. It might be wider than this in other configurations,
such as when it is fitted with a missile launcher or with slabs of
appliqué armour fitted to the hull side skirts.
The height of CRV will also affect its transportability in some
specific circumstances. Vehicle designers try to make their
vehicles with as small a profile as possible but the requirement for
internal volume, mine protection, seating for a 95th percentile
male, a large turret, a remote weapon system (RWS) and
surveillance sensors means that CRV will exceed 3.2-3.5m in
height. This is higher than current-generation main battle tanks.
This increased width and height will introduce a number of
restrictions for transportability by road, rail, ship and aircraft.
Movement on LHD and LLC will not be affected. CRV will clearly
not be transportable on C-130, but despite its height will be a
drive-on/drive-off load for carriage by C-17 (cargo bay height is
3.96-4.5m) unless a RWS is mounted on the turret roof. CRV will
probably not be transportable by rail through the smallest railway
tunnel but will pass through most other railway profiles. There
may also be some restrictions when carried on high bed trucks.
In general, however, these are considered minor compromises
compared with the increase in combat power which the CRV
SOFT SOIL MOBILITY
Mobility in soft soil conditions is the area in which some
anticipate CRV will be most compromised compared with
ASLAV because it will be so much heavier. This may not be the
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