August 27, 2012
Credit: Credit: Northrop Grumman
Graham Warwick Washington and John Doyle Las Vegas
As wars wind down and budgets tighten, a 12-month delay can make a big difference to a program, but with the first flight of Northrop Grumman's Long Endurance Multi-Intelligence Vehicle (LEMV), the U.S. Army's support, and need, for a persistent-surveillance airship seems to be holding firm.
Now back in its hangar at Lakehurst, N.J., following the first flight on Aug. 8, the 300-ft.-long hybrid airship is being inspected externally, with checks to the envelope fabric and seams, hard structure, fuel system and other areas. “That will take a while,” says Alan Metzger, Northrop vice president and LEMV program manager.
In parallel, Northrop is continuing installation of wiring for the payloads, which will be added halfway through flight testing. “We did not install payloads for the first flight, but all the hard structure was on the aircraft, including the empty payload bays,” Metzger says. “Everything needed to fly in manned configuration was on board.”
The first flight accomplished three things, Metzger says: a takeoff, basic aircraft functions including climbing and maneuvering, and a landing. “We were airborne 90 minutes and there were no big issues,” he says. Although lacking its payload, the airship was heavier than air and used its vectoring thrusters to take off vertically.
As a hybrid airship, the LEMV uses a combination of aerodynamic, buoyant and propulsive lift. Being heavier than air makes the aircraft easier to handle during takeoff and landing. Fully loaded, the LEMV will require a short takeoff run, but Metzger says there are restrictions at Lakehurst because the hangars are nearby.
The aircraft is powered by four identically configured Centurion Aircraft Engines turbo-diesels, two forward thrusters and two at the rear. Generators on each engine provide electrical power for the aircraft and payload. “We can run the entire air vehicle off one engine, in its current configuration, and run with 1-4, based on the mission profile,” Metzger says.
The LEMV is designed to fly unmanned at 22,000 ft. for 21 days carrying 2,750 lb. of intelligence, surveillance and reconnaissance (ISR) sensors. “We will carry 6-10 payloads, depending on size, and stay up longer than any tactical asset,” says Metzger. “We can do more with less, and eventually that will save money.”