Autonomously-Controlled Lear Holds Position Around
KC-135
Aero-News learned Monday that Boeing's Automated Aerial
Refueling (AAR) program successfully completed flight tests in
August that demonstrated for the first time an unmanned air
vehicle's ability to autonomously maintain a steady refueling
station behind a tanker aircraft.
"With autonomous air refueling capabilities, unmanned aircraft
will have greater combat radius and loiter time," said David Riley,
Boeing Phantom Works AAR program manager. "This can enable a
quicker response for time-critical targets and will reduce the need
for forward-staging refueling areas. Another benefit is increased
in-theater military presence with fewer military assets."
Boeing Phantom Works conducted the flight tests with the New
York Air National Guard 107th Air Refueling Wing, which provided a
KC-135R refueling tanker, and Calspan Corp., which provided a
Learjet equipped with a special Boeing flight control system that
allowed it to fly as an unmanned air vehicle. The flight tests
integrate components on both the tanker and receiver aircraft to
demonstrate that the receiver aircraft (the UAV) can autonomously
hold position relative to the tanker while the tanker executes its
standard air refueling maneuvers.
Six flights were conducted with the Boeing flight control system
engaged, which enabled the Learjet to autonomously hold various
positions in space -- contact, pre-contact or observation -- around
the KC-135R. During a flight on August 15, the Learjet was flown
manually to the contact position behind the KC-135R -- the point
from which Air Force aircraft receive fuel from a tanker's
refueling boom. The aircraft's flight control system was then
engaged, said Riley, and it autonomously held the contact position
for 23 minutes while the tanker flew two full air refueling orbits,
or holding patterns.
Two previous flight test efforts were conducted in August 2004
and September 2005 to evaluate the suitability of the Learjet
behind a KC-135 and to take GPS measurements to determine
positioning for future flights. As a prelude to the Station-Keeping
Flight Test, some Learjet inner-loop flight control laws were
tested.
The AAR flight test program will continue through 2007 to
complete this phase of the program and ready the technology for
transition to Air Force assets. Over the next year, the AAR team
will build on the success of the station-keeping flight tests that
will lead to new automated refueling capabilities.
In August 2007, the AAR team will demonstrate autonomous
maneuvering around the tanker. The Learjet will engage the AAR
system at the observation position on the tanker wing and will be
directed from a control station to go to the pre-contact and
contact positions upon approval from the tanker crew.
Phantom Works -- which built the AAR flight control computer,
developed the station keeping control laws, and is conducting the
flight tests -- is the advanced R&D unit of Boeing. Its charter
is to provide innovative technology solutions that reduce the cycle
time and cost of aerospace products and services while improving
their quality and performance.
The AAR team also includes a diverse set of government and
contractor organizations.