US Marines RST-V Hybrid Tactical Vehicle

The US Marine Corps' first 4x4 hybrid-electric tactical vehicle - the Shadow RST-V - has been tested by the Office of Naval Research (ONR) and the Defence Advanced Research Projects Agency (DARPA) and may soon challenge the Humvee as the dominant vehicle for military use. The Reconnaissance, Surveillance and Targeting Vehicle (RST-V) is a high mobility, electric drive technology demonstrator that incorporates a lightweight diesel engine coupled to a permanent-magnetic generator which drives four in-hub permanent-magnet electric wheel motors. The RST-V is ideally suited as a reconnaissance vehicle, as its lithium-ion battery pack enables silent movement for upwards of 20 miles with extremely low thermal and acoustic signatures.

The vehicle has an aluminium body with an optional armour package providing protection against small arms fire and mines, and fits a crew of four. There are two doors on the sides and a ramp at the back for entry to the internal cargo area. Bulletproof windows can be installed on the front and sides.

"The RST-V offers a tremendous amount of enhanced capabilities to the warfighter," said Jeffrey Bradel, ONR Manoeuvre manager. "This is a technology demonstrator... to show the Marine Corps leadership the potential benefits that these advanced technologies provide on the battlefield."

Four vehicles were fabricated and subjected to performance testing and operational user evaluations during the last few years, including more than 7,000 miles of field-testing and numerous demonstrations including two 1,000 mile endurance runs. In September, 2003, the Marine Corps Warfighting Laboratory organized a two-week joint service Limited Objective Experiment for the RST-V at the Army's Yuma Proving Grounds in Yuma, Arizona. The vehicle successfully completed cargo loading, silent operation, live firing and severe off road exercises. Additionally, the RST-V shattered the speed record for the Army's Rock Ledge Course at Yuma with a time of 13 minutes and 50 seconds. The previous record was over 32 minutes.

"In most cases we matched or exceeded the Humvee's capabilities," said General Dynamics' Tom Trzaska, citing improved mobility, recon ability, and providing a better platform for employing a machine gun such as the M2 .50 Cal Browning. The RST-V also has a significant edge over the Humvee in fuel economy. The average fuel usage for a deployed Humvee conducting an extended reconnaissance mission is 1,040 pounds per month, but only 440 pounds for the RST-V.

"The RST-V reduces the foot print you have to take to the field through increased fuel economy," said Trzaska.

It may also be used for light strike duties, as a battlefield ambulance, for air defence, logistics, as a personnel carrier or as anti-armour and a mortar weapons carrier once the System Design and Development (SDD) phase is completed by ONR in 2005.

Propulsion System

The Shadow runs on a hybrid-electric drive based on a front mounted turbocharged, inter-cooled common rail direct injection diesel engine, type 2.5 litre DI-4V rated at 114kW. The diesel engine powers a 110kW Magnet Motors permanent magnet generator that drives four 50kW Magnet Motors permanent magnetic hub motors, mounted one in each of the Shadow's four wheel hubs.

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