The U.S. Navy’s unmanned combat air system demonstrator has taken two key steps toward demonstrating autonomous operation from an aircraft carrier at sea next summer.
On Nov. 29, the firstX-47B air vehicle, AV-1, made its first catapult launch from a land-based test facility at NAS Patuxent River, Md. A second launch was planned for Nov. 30.
Earlier in the week, on Nov. 26, the second X-47B—AV-2—was hoisted aboard the aircraft carrier USS Truman at NAS Norfolk, Va., to begin a few weeks of deck-handling trials in port and at sea.
So far, AV-2 has completed engine runs, telemetry and communications checks, and been moved around the flight deck and hangar bay. Once the Truman is underway, the X-47B will be maneuvered through simulated carrier operations using a wireless hand controller.
Using the control display unit (CDU), the deck operator will maneuver the unmanned aircraft around the flight deck, in and out of the arrestor wires and catapult, and up and down the elevators, says Don Blottenberger, Navy deputy program manager.
Demonstrated in earlier ground taxi tests at Patuxent River, the CDU enables the operator to wirelessly control engine thrust, nose-wheel steering, main-wheel braking, flight-control sweeps and lowering and raising the tailhook.
Back at Pax River, the Navy will clear the limited catapult-launch envelope planned for the demonstration while it completes development of the software load required to begin shore-based arrested landings. These are expected to begin early in 2013, Blottenberger says.
A redesign of the tailhook point to ensure it catches the wire has been successful, says Capt. Jaime Engdahl, Navy program manager. The original design used an F-14 hook point, but did not reliably catch the wire in tests.
“We did a quick redesign, in 45 days, and have done three arrestment roll-ins, all successful,” he says. The problem is caused because the tailhook is closer to the main gear on the tailless X-47B and has less time to bounce back.
On the first steam-catapult launch, the X-47B reached 147.6 kt ground speed and 151.3 kt airspeed at launch, says Mike Mackey, Northrop Grumman UCAS-D program manager. On climb-out the aircraft reached 12.5-deg. peak pitch, with nominal loads, he says.
The unmanned aircraft reached 1,200-ft. altitude during its 10-min. autonomous flight and flew a standard carrier precision-approach pattern, Mackey says, flying a 3.25-deg. glideslope to a landing rollout and full stop on the runway at Pax River.
Blottenberger says there is an option to fly AV-1 into the carrier-controlled airspace around the Truman while it is at sea, conducting deck-handling trials with AV-2. The carrier to be used for the 2013 launch and recovery demonstration has not been identified.
All of the Navy’s East Coast-based Nimitz-class carriers are being modified temporarily to operate with the X-47B, Engdahl says. This includes installing a mission control element, relative navigation system and data links.