Military

X-47B completes first ever unmanned refueling exercise

X-47B completes first ever unm...
The X-47B receives fuel from an Omega K-707 tanker April 22 while operating over the Chesapeake Bay (Photo: US Navy)
The X-47B receives fuel from an Omega K-707 tanker April 22 while operating over the Chesapeake Bay (Photo: US Navy)
View 17 Images
The X-47B in flight tests (Photo: US Navy)
1/17
The X-47B in flight tests (Photo: US Navy)
X-47B in flight after first-ever catapult launch from USS George H.W. Bush in May 2013 (Photo: US Navy)
2/17
X-47B in flight after first-ever catapult launch from USS George H.W. Bush in May 2013 (Photo: US Navy)
UCAS-D taking off of a carrier during July 2013 trials (Photo: US Navy)
3/17
UCAS-D taking off of a carrier during July 2013 trials (Photo: US Navy)
UCAS-D landing during July 2013 carrier trials (Photo: US Navy)
4/17
UCAS-D landing during July 2013 carrier trials (Photo: US Navy)
UCAS-D landing aboard USS Bush during July 2013 carrier trials (Photo: US Navy)
5/17
UCAS-D landing aboard USS Bush during July 2013 carrier trials (Photo: US Navy)
UCAS-D landing aboard USS Bush during July 2013 carrier trials (Photo: US Navy)
6/17
UCAS-D landing aboard USS Bush during July 2013 carrier trials (Photo: US Navy)
UCAS-D taking off of the USS Bush during July 2013 carrier trials (Photo: US Navy)
7/17
UCAS-D taking off of the USS Bush during July 2013 carrier trials (Photo: US Navy)
The X-47B showing refuelling drogue (Photo: US Navy)
8/17
The X-47B showing refuelling drogue (Photo: US Navy)
The X-47B receives fuel from an Omega K-707 tanker April 22 while operating over the Chesapeake Bay (Photo: US Navy)
9/17
The X-47B receives fuel from an Omega K-707 tanker April 22 while operating over the Chesapeake Bay (Photo: US Navy)
X-47B completes first shore-based arrested landing at Pax River (Photo: US Navy)
10/17
X-47B completes first shore-based arrested landing at Pax River (Photo: US Navy)
UCAS-D in flight (Photo: US Navy)
11/17
UCAS-D in flight (Photo: US Navy)
UCAS-D with wings folded (Photo: US Navy)
12/17
UCAS-D with wings folded (Photo: US Navy)
Infographic covers major milestones for the last several years (Photo: US Navy)
13/17
Infographic covers major milestones for the last several years (Photo: US Navy)
X-47B flies over NAS Patuxent River, Md. in August 2012 (Photo: US Navy)
14/17
X-47B flies over NAS Patuxent River, Md. in August 2012 (Photo: US Navy)
A perfect landing for the X-47B at the conclusion of the first flight at Edwards AFB (Photo: US Navy)
15/17
A perfect landing for the X-47B at the conclusion of the first flight at Edwards AFB (Photo: US Navy)
The X-47B takes to the blue skies of Edwards AFB on its first flight (Photo: US Navy)
16/17
The X-47B takes to the blue skies of Edwards AFB on its first flight (Photo: US Navy)
X-47B aboard USS Truman in December 2012 (Photo: US Navy)
17/17
X-47B aboard USS Truman in December 2012 (Photo: US Navy)

The US Navy's X-47B Unmanned Combat Air System Demonstration (UCAS-D) aircraft has gone out on a high note (and added yet another acronym to the military lexicon) by conducting the first ever Autonomous Aerial Refueling (AAR) exercise. The autonomous aircraft rendezvoused with an Omega K-707 tanker plane off the coast of Maryland and Virginia, successfully taking on 4,000 lb (1,814 kg) of jet fuel as it completed the project's final test objective.

At a press conference, Captain Beau Duarte, the Navy’s Unmanned Carrier Aviation program manager, confirmed that on April 22, the X-47B carried out the last of four refueling exercises. During Wednesday's test, the robotic aircraft became the first to autonomously approach a tanker, secure a refueling drogue, take on fuel, and disconnect. This was the last in a series of demonstrations to show that an unmanned aircraft can carry out standard Carrier Air Wing operations.

Duarte emphasized that the X-47B was not remotely piloted during the refueling. Instead, the ground controller and tanker crew gave commands for the aircraft to carry out tasks and the onboard computers executed the maneuvers, handling not only navigation, but also the rapid movements of the two aircraft and the resulting feedback loops.

The X-47B showing refuelling drogue (Photo: US Navy)
The X-47B showing refuelling drogue (Photo: US Navy)

During the exercise, the X-47B carried out Navy-style refueling, which uses a probe-and-drogue method where the tanker plane trails a fueling tube that ends in a conical basket, or drogue, while the following aircraft extends a probe into the basket to link up and take on fuel.

This is a tricky exercise even for a human pilot, but the X-47B accomplished the task using an infrared camera linked to a new visual computer to home in on the basket, a government-designed Refueling Interface System (RIS) aboard the tanker to communicate between the two aircraft, and a combination of GPS and inertial navigation systems.

This system allowed the X-47B to approach the tanker, close the distance, find the basket, insert the probe, and fly in formation for 11 minutes while it took on fuel before ground control ordered it to disconnect and return to base.

Under a contract with the US Navy, Northrop Grumman built two X-47B demonstrators named Salty Dog 501 and Salty 502. Though the X-47B is unmanned, it is not a drone. Instead, it’s an autonomous aerial vehicle, which means that it flies missions according to pre-programmed instructions rather than being under constant control by a ground-based pilot.

UCAS-D in flight (Photo: US Navy)
UCAS-D in flight (Photo: US Navy)

The aircraft were designed to demonstrate autonomous carrier operations including launch, recovery and operations within 50 nautical miles (57.5 mi, 92.6 km) of the carrier. Only one of the two demonstrators built is designed for autonomous aerial refueling operations using the Air Force “boom/receptacle” approach as well as the Navy probe and drogue method. No weapons were carried by either aircraft and no sensor tests were conducted.

The Navy says that the next step as far as refueling goes will be to develop a more robust and reliable system that can operate outside of land range and in a variety of weather conditions, which might mean using different approaches than the one used on Wednesday. However, this will have to wait because efforts will now concentrate on the Navy's Unmanned Carrier-Launched Airborne Surveillance and Strike (UCLASS) aircraft.

The X-47B is a demonstrator and its design is very different from UCLASS and the Navy contends that it would be impractical to rebuild it for the UCLASS program. The Navy will instead use what remains of the program's budget to conduct further testing before the aircraft are mothballed or sent to a museum.

"What we accomplished demonstrates a significant, groundbreaking step forward for the Navy," says Duarte. "The ability to autonomously transfer and receive fuel in flight will increase the range and flexibility of future unmanned aircraft platforms, ultimately extending carrier power projection."

The video below shows Wednesday's test.

Source: US Navy

NAVAIR Clips: X-47B completes first autonomous aerial refueling

6 comments
David Clarke
A fairly interesting video, but a bit like watching paint dry.A lot of effort to prove a concept. Now the two aircraft are going to be mothballed. I wonder how many billions of dollars this project cost the taxpayer. It strikes me as ironic that however wonderful the American military is at creating killing machines, they still cannot defeat the enemy in guerrilla warfare, who are mostly using Kalashnikov rifles, which are not very expensive weapons.
bobcat4424
The disastrous F-35 has pretty much ended the days of manned combat aircraft. Unmanned craft are cheaper, more maneuverable, and if one is shot down, there is no POW to deal with. The UCAV can remotely CAP an area with refuelings and have a considerably time on station that a manned aircraft. And can penetrate highly defended targets in a way that does not risk pilot lives. These two aircraft are likely the largest step forward since the Navy started carrier aircraft. The UCAV is also a step forward in carrier landings in weather conditions that would be extremely dangerous for a manned aircraft.
Stephen N Russell
Saw this in movie Stealth from giant airship tankers for jets
toolman65
The F 22 contains software to limit the plane's performance. In order to keep the pilots from blacking out during combat. The days of UAV combat will soon be upon us. Until then, the priorities will be: 1) refuel 2) find Sarah Conner
Douglas Bennett Rogers
We are already ahead of the invaders in Independence Day!
christopher
Last in series of 4 refueling tests, and first successful.. so basically - 3 out of 4 tests failed :-) Note how the refuel probe was a temporary addon (not built in) - my guess is they decided to see how fast and well they could add a new feature that the robot could "learn" to use. Pretty cool.