U.S. Army need for long-duration surveillance beyond Afghanistan keeps airship hopes afloat
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.As wars wind down and budgets tighten, a 12-month delay can make a big difference to a program, but with
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.”
Some 10-15 manned flights are planned from Lakehurst, he says, before the LEMV relocates for the next phase of payload and eventual unmanned testing. The remote pilot system is still in development, but “we flew the first unmanned software build on the first flight, and used it for data collection to validate our simulations.”
The LEMV draws on Northrop's other unmanned aircraft systems, with “better than 90% reuse from other platforms,” he says. AAI Corp. is supplying a version of the Army's universal ground control station to operate the aircraft and SAIC is providing expertise in full-motion video.
When Northrop's $154 million contract was signed in June 2010, the LEMV was scheduled to fly within 12-13 months and be ready for deployment to Afghanistan within 18 months. “The system was more complex than we anticipated,” says Metzger. “This is an aircraft the size of an, with rotating engines. We went from concept to first flight in 25 months. That was a remarkable achievement.”
Lt. Gen. Mary Legere, Army deputy chief of staff for intelligence, says the first flight capped “25 months of very hard work” by Northrop, its airship design partner Hybrid Air Vehicles in the U.K., “and some great smaller companies coming together, working off a PowerPoint slide, understanding the need for persistent surveillance and bringing that forward.”
Delays resulted from additional design iterations, manufacturing issues and storms that hampered preparations for first flight. “We've added robustness, with double and triple redundancy in certain areas. There is more stuff in the vehicle, and that meant more drawings, more wires and more design, integration and test,” Metzger says.
Northrop's contract is potentially worth $517 million, including options that have still to be exercised for two more vehicles. “The Army's acquisition strategy was to build the first one and check the 'Technically feasible' box. I believe we've checked that box,” Metzger says.
“The Army still wants to go to 20,000 ft. and stay there for a few weeks carrying a lot of stuff,” he says. “Article 1 falls short in some areas. On the second one, we'll fix the things that do not perform on air vehicle 1, and, by the third, everything will be tightened up. . . . We have quite a bit of margin in the vehicle to accommodate changes.”
Northrop is working with the Army on a product-improvement road map—“things they want to see changed, new ideas and evolving requirements,” Metzger says. “We are also refining our cost and schedule estimates. Some things just take longer than we thought.”
“We have some work to do on sensor integration,” says Legere. “I'm an optimist. I have a feeling this capability is going to be available to the theaters that need this now, and it's going to help us use all of our intelligence systems to greater advantage.”
The LEMV was aISR Task Force initiative the Army took on, she says, “because it is our soldiers that are going into these regional conflicts where we may not get the apportionment of strategic ISR and . . . where we're going to be the only game in town for a very long time. So we're going to be looking for that persistence.”