RST-V
General Dynamics Proposal
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The US Marine Corps
is planning a new
Reconnaissance, Surveillance and Targeting Vehicle (RST-V).
In other words it is designing Jeep 2000+.
RST-V will be a light (less than four tons) four wheel drive
capable of being carried in the Boeing V-22 (Osprey)
vertical takeoff and landing transport plane,
which limits its width to 5' (1.6 metres)
and its height to 5'8'' (1.7 metres).
The RST-V will carry three or four marines across country
on roles near to and behind enemy lines.
This requires a degree of "stealth" technology
to prevent detection.
The RST-V has some novel requirements:
it must use a hybrid electric propulsion system.
This will incorporate a diesel engine driving a heavy duty
alternator to power electric motors at each wheel and
to charge a battery pack.
There is no conventional mechanical transmission.
A hybrid propulsion system brings various advantages.
The vehicle can run for 10 or 20 miles on battery power
alone, in which mode it generates little sound
and little hot-exhaust "signature" -
for infra-red detectors to pick up.
When the diesel is operating, its exhaust
is mixed with cooler air to reduce the chances of detection.
(A low radar signature is much harder to achieve in a ground vehicle
due to the need for cooling-air inlets, wheel arches and
other openings.)
There were battery powered trucks on the roads in the late 19th century
and early 20th century.
Diesel-electric transmission has been used in some high power situations,
e.g. railway locomotives and heavy earth-moving equipment.
Recent pressures to reduce emissions and increase fuel efficiency,
together with improvements in electric motors,
battery technology and electronic power control,
have created new interest in electric and hybrid power systems
for smaller vehicles.
- 4wd.sofcom.com/4WD.html
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A smaller diesel engine can be fitted because it only
needs to meet the RST-V's average power requirements;
the batteries can help out to meet the peak requirements,
i.e. under acceleration and hill climbing.
The diesel can operate at optimum efficiency settings
and simply stop when the batteries are charged.
Altogether this makes for greater fuel efficiency,
even taking account of the weight of the battery pack,
and is one reason why car (4x2) makers are considering hybrid power systems
(e.g. the Hyundai FGV-1 at a recent
motor show).
For the military, fuel efficiency means greater range and
an easing of logistical problems in supplying fuel to forward operations.
The effects of four wheel drive, gearing, diff' locks
and traction control are all managed by computerized control
of the four electric motors.
Should the diesel engine fail,
or even one or two of the electric motors,
the vehicle may still be able to limp home
and reach safe territory.
The Marine Corps is already experimenting with
hybrid power systems, fitting one to a buggy
known as the Joint Tactical Electric Vehicle (JTEV).
Test Humvees (HMMWVs) have been similarly equipped,
demonstrating a dramatic improvement in fuel consumption (not hard)
and greater acceleration compared to the usual diesel Hummer -->
Humvee.
Onroad, the RST-V must cruise at 100kph.
Offroad, an advanced suspension system is required
for high speed cross-country travel,
and to handle 40 degree side-slopes.
An active suspension systems of some sort will be needed.
(In Australia, the
Kinetic
hydro-pneumatic suspension and the
Fielder
semi-active pneumatic suspension
may be indicators of things to come.)
The Defense Advanced Research Projects Agency (DARPA)
is a partner in the RST-V project with the US Marine Corps
in consideration of the advanced technology that will be
needed for the novel power and suspension systems plus
armour and sensors.
- 1997 November:
Lockheed Martin Vought Systems and
General Dynamics Land Systems
selected to each provide a prototype RST-V.
- 1998/1999: one company selected to build and test two vehicles.
- 1999-2001: test period.
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