Quallion X-51A Lithium-Ion Battery. Click to enlarge.

Quallion developed a high discharge rate 3.3Ah pouch cell for the X-51. The program chose to use rechargeable lithium-ion chemistry over the traditional silver-zinc solution to reduce ground maintenance prior to launch, which would allow for testing of the system without the need to replace the battery. Thus, Quallion LLC developed a high energy density and high discharge rate pouch cell to be the basis for three separate battery packs enclosed in one envelope on the vehicle.

This cell design had to be robust enough to handle three different performance requirements while maintaining the program’s weight goals.

The 3.3Ah cell is designed for greater than 10C capabilities for more than 50 cycles and high safety characteristics, with a gravimetric energy density of 120 Wh/kg and volumetric energy density of 252 Wh/L.

Quallion is developing an advanced lithium-ion anti-idling HVAC system for heavy-duty trucks, and is also targeting its systems for hybrid, plug-in hybrid and battery-electric vehicles.

WaveRider. On 26 May, in its first flight attempt, the Boeing X-51A WaveRider successfully completed the longest supersonic combustion ramjet-powered flight in history—nearly three and a half minutes at a top speed of Mach 5. The Waverider ScramJet Demonstrator Program is sponsored by the US Air Force Research Laboratory (USAFRL) and built by a consortium of The Boeing Company and Pratt & Whitney. The hypersonic—i.e., in excess of Mach 5 (3,800 mph; 6,145 km/h)—test vehicle is designed to achieve Mach 6+ speeds at an altitude of 100,000 feet.

During its first flight, the unmanned WaveRider vehicle was carried beneath a US Air Force B-52 and dropped from an altitude of about 50,000 feet over the Pacific Ocean off southern California. A solid rocket booster fired and propelled the cruiser to greater than Mach 4.5, creating the supersonic environment necessary to operate the engine.

The booster was then jettisoned and the Pratt & Whitney Rocketdyne SJY61 scramjet engine ignited, initially on gaseous ethylene fuel. Next the engine transitioned to JP-7 jet fuel, the same fuel once carried by the SR-71 Blackbird before its retirement.

The vehicle’s fuel-cooled engine design serves both to heat the JP-7 to an optimum combustion temperature and to help the engine itself endure extremely high operating temperatures during the long burn.

The flight reached an altitude of about 70,000 feet and an approximate speed of Mach 5.

There are three remaining test vehicles for future test flights.