The US Navy has detailed the 29 November ground-based catapult launch of the Northrop Grumman X-47B, a key milestone in the path to carrier-based operations.

"Rotation and fly-out showed excellent flight dynamics," says Captain Jaime Engdahl, programme manager for unmanned combat air systems-demonstrator (UCAS-D), "with normal or nominal [aerodynamic] loads throughout the flight".

"We've gone through thousands of flights in simulations," he adds. "If you were to look at the simulations and our event yesterday, you would have seen no differences."

The aircraft was launched using a profile "very representative" of actual carrier launch conditions, according to Northrop, using a relatively benign but operable combination of takeoff weight, catapult force and headwinds.

The aircraft lifted off at 147kt (272km/h).

The launch marks the first of a "very conservative build-up" of speed, weight and forces as the navy simulates a catapult launch at sea.

"As we go through testing, it's pretty standard to take a conservative approach, at least initially," says Engdahl.

The aircraft will be launched several more times from the ground catapult before an actual aircraft carrier launch, planned for mid-2013.

The aircraft was manoeuvred to the catapult, on a runway at NAS Patuxent River, using the same model of handheld control display unit that controls the second air vehicle, which is currently aboard the aircraft carrier USS Truman undergoing deck handling tests.

The ship-based air vehicle is being used to establish and test deck handling, including exit from the landing area - involving disconnecting from the arrest wires that halt the aircraft abruptly - entry into the catapult area, and moving from the deck to the hangar bay using onboard elevators.

"We will do all of the integration work on the catapult -- in fact, taxi it up and position it on the catapult," says Engdahl. "We actually have many, many first steps to go before we catapult off a carrier."

Source: Flight International