Lockheed Martin (Bethesda, MD) and the US Army National Automotive Center are displaying a 5-ton tactical truck powered by a new hybrid diesel-electric propulsion system at the Association of the US Army's Symposium and Exhibition this week. The truck, part of the Army's Family of Medium Tactical Vehicles, utilizes the HybriDrive propulsion system developed by Lockheed Martin Control Systems. The vehicle employs electric drive motors, a diesel-powered generator, batteries, and an electronic control system.The truck's drive motors are power by the batteries, which are continually recharged by the on-board generator. The diesel engine turning the generator runs at nearly constant speed for optimum performance, so that the truck consumes 25 to 50 percent less fuel compared to a standard diesel configuration. The HybriDrive system is also claimed to provide more torque for sudden acceleration and hill-climbing and produce about half the exhaust emissions.