The U.S. Air Force’s newest refueling tanker, the KC-46 Pegasus, recently made its first mid-air connection with the B-2 Spirit stealth bomber in the skies over Edwards Air Force Base, California.
The Air Force took first delivery of the KC-46 earlier this year and the milestone was completed during the Phase III testing of the aircraft.
“Testing with the B-2 was a pretty big deal for us,” said Jamie Smith, 418th Flight Test Squadron lead aerial refueling engineer. “It is the first aircraft that has such a dark paint scheme and it takes up quite a large portion of the Remote Vision System (RVS) screen. We were all really interested to see how the RVS would react with the B-2.”
“We are looking for data such as the bow-wave effect from the tanker on the receiver and how it affects receiver handling qualities, boom handling qualities, whether the visual reference indications are satisfactory to both aircrews, if the two aircraft are mechanically compatible: no nozzle binding during contacts, if the fuel systems are compatible with one another, and, determine the aerial refueling envelope; altitude and airspeed,” Smith said.
“The up-wash at the leading edge of the flying wing is dynamic compared to the bow wave at the nose of a conventional receiver aircraft. This dynamic airflow environment in close proximity to the horizontal stabilizer of the tanker is something we are looking to understand and characterize throughout all test missions.”
“This was a first flight of sorts for both of these aircraft,” said Maj. Matthew Gray, 419th FLTS test pilot and flight commander. “Never before has a flying wing refueled behind the KC-46 and as such, we tested unique aerodynamic influences while proving system capabilities.”
Gray serves as the B-2 flight commander and said the mission presented unique challenges and important engineering data. The data gathered from the pairing during the developmental testing phase will impact how the KC-46 operates in the near future. Engineers are looking for information pertaining to flight characteristics as well as other data.
“The flying wing design of the B-2 poses unique challenges to the flying and handling qualities of the tanker-receiver pair,” Gray said.
“The KC-46 provides significant added capability over the workhorse of the tanker fleet, the KC-135. It is configured all the time to configure both boom (U.S. Air Force) and drogue (U.S. Navy, foreign) receivers, whereas the KC-135 can generally only refuel one type or the other on a given sortie,” said Maj. Jacob Lambach, 418th FLTS flight test pilot.
“It has the capability to carry up to 18 pallets of cargo, versus six for the KC-135, which is especially helpful when moving both aircraft and their support personnel and equipment across the ocean.”
With the connection with the B-52 Statofortress long-range strategic bomber last summer, and now the B-2, the KC-46 has successfully connected with two of the three bombers in the Air Force inventory. The third one in the USAF inventory is the B-1B Lancer supersonic bomber.
While the B-2 pairing tests are still ongoing, plans are now being developed to pair the KC-46 with the B-1, said Rachel Johnson, 418th FLTS flight test engineer for the KC-46/B-2 certification test program.