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
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.
Go to the
4WD Vehicles A-Z
4WD Toys & Models
History of 4WDs