Navy E-2C Hawkeye Undergoes Major Loads Tests at NASA Dryden

Dryden Flight Research Center
P.O. Box 273
Edwards, California 93523
Phone 661/276-3449
FAX 661/276-3566

Alan Brown
NASA Dryden Flight Research Center
Phone: 661/276-2665


RELEASE: 05-08

NAVY E-2C HAWKEYE UNDERGOES MAJOR LOADS TESTS AT NASA DRYDEN

A U.S. Navy E-2C Hawkeye, a carrier-based electronics aircraft that
serves as the eyes and ears of carrier battle groups, recently
underwent structural loads tests at NASA Dryden Flight Research
Center's Flight Loads Laboratory to determine if increasing the
aircraft's gross weight will affect its performance.

The Hawkeye, distinctive with its 24-foot diameter rotating radome and
quadruple vertical tails, is part of a fleet of aircraft that has
been operational for more than 40 years. The Navy is planning
upgrades that will add weight to the aircraft. Navy officials asked
NASA Dryden to help formulate loads equations aimed at determining
how the additional weight will affect the aircraft's flight envelope.

"A loads calibration test is a primary part of the development of any
new aircraft," explained Paul Lundstrom of Spiral Technology,
Dryden's lead test engineer on the project. "It's also an important
step in determining the flight envelope for any new configuration of
an aircraft. So when you get a new configuration or a new aircraft,
you absolutely have to know what the structural loads are on the
airplane when it's in flight. The only good way to determine that is
by doing a test of this nature."

The aircraft arrived at Dryden last fall from its base at the Naval
Air Warfare Center Aircraft Division (NAVAIR) at Naval Air Station
Patuxent River, Md. A Navy crew removed the engines and propellers,
purged fuel tanks and performed other preparations before NAVAIR and
Dryden technicians began installing loads sensors and other equipment
for the structural tests. The work was completed in mid-March about
three weeks ahead of schedule.

The tests in Dryden's Flight Loads Laboratory applied force, or loads,
on the aircraft to develop loads equations, using a data-recovery
system connected to instrumentation on the airplane, said Lundstrom.

"That data is used to develop what we call loads equations," Lundstrom
added. "These loads equations can be used (by Navy flight test
engineers) to estimate loads while they're test-flying the airplane.
This allows them to know when they're approaching in-flight loads
that are too high for the structural capacity of the aircraft. A
loads calibration allows us to define the performance parameters of
the aircraft while maintaining a safe structure."

The E-2C research isn't the biggest project completed in Dryden's
Loads Laboratory, but it is among the largest ever undertaken and
could lead to similar work in the future, he added.

An unmodified E-2C weighs about 42,000 pounds empty. The Hawkeye that
was tested at Dryden had its weight beefed up with metal plates to
simulate an empty weight of about 45,000 pounds -- mimicking the
latest weight configuration of the upgraded E-2D Advanced Hawkeye,
more commonly known as the "Hummer" in the fleet. Loads were applied
to the aircraft's wings and tail.

The E2-C has an 80-foot wingspan, is about 58 feet long and 18 feet
tall. Dryden's Loads Laboratory can accommodate the aircraft with
room to spare for equipment and fixtures necessary for conducting the
research.

NAVAIR personnel installed 226 strain gauges, which measure stress on
the aircraft's surface, while NASA technicians mounted 15 string
potentiometers, which essentially are electronic measuring tapes, on
the aircraft. Six load cells -- instrumentation that records how
large a force is being applied to an area -- measured aircraft
reactions at fixed points on the ground. An additional 24 load cells
were used to monitor and control loads applied to the wings; another
eight were used for the tail.

NAVAIR project engineer Jason Brys said the Navy has been pleased with
the progress that has been made to date.

"We had a few obstacles during the preparation process, but the
three-party team of NASA, NAVAIR, and Northrop Grumman Corp. have
come up with timely solutions," he said.

"The Navy decided to use NASA Dryden because they have unique
facilities and experience that are hard to find elsewhere, and I am
pleased with the support that we have received from Dryden to date,"
Brys added.

Lundstrom said the tests on the E-2C illustrate one of two core
competencies of the NASA Dryden Flight Loads Lab.

"We're one of the few locations in the nation that can do this
specific type of test," he said. "Our second very important
capability that we're still in the process of developing and growing
and learning more about, is testing under extreme thermal conditions.
We have a strong tradition here at Dryden for testing for both of
those types of information."

The E-2A Hawkeye first entered service in 1961, was updated in 1969 as
the E-2B and the E-2C was introduced in 1973. It performs a similar
role to the Air Force E-3 Airborne Warning and Control System, also
known as AWACS.

Built by Northrop Grumman, the Navy's Hawkeye has extensive
communication and long-range surveillance radar capabilities. It is
considered the "quarterback" -- or manager -- of carrier-group
operations, and boasts the ability to monitor six million cubic miles
of airspace and more than 150,000 square miles of ocean surface while
detecting hundreds of ships, aircraft, missiles, or targets up to 200
miles away.

PHOTO EDITORS: High-resolution photos to support this release are
available electronically on the NASA Dryden photo gallery at:
http://www.dfrc.nasa.gov/Gallery/Photo/E-2C/index.html.

TELEVISION EDITORS: Interview segments and B-roll footage to support
this release will be aired during the Video File feeds on NASA TV
beginning on March 23. NASA TV is available on the Web and via
satellite in the continental U.S. on AMC-6, at 72 degrees west
longitude, transponder 9, 3880 MHz, vertical polarization, audio at
6.8 MHz. In Alaska and Hawaii, NASA TV is available on AMC-7, at 137
degrees west longitude, transponder 18, at 4060 MHz, vertical
polarization, audio at 6.8 MHz. For NASA TV information and schedules
on the Internet, visit: http://www.nasa.gov/ntv


-end-


--
--------------

Jacques :-)

www.spacepatches.info