- The U.S. Navy plans to begin testing a prototype for
an unmanned underwater glider with a flying-wing design in March, according
to the Office of Naval Research, which funds the project.
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- If successful, tests of the Flying Wing Underwater Glider
could lead to a new generation of gliders that researchers expect to be
the largest and fastest to date. They would be capable of traveling thousands
of miles under ocean waves, quietly conducting surveillance and gathering
data for military and civilian purposes, researchers said.
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- "Gliders have the potential of providing long-endurance
mobile platforms for employing sensors," said Thomas Franklin Swean
Jr., team leader for Ocean Engineering and Marine Systems Science and Technology
at the Office of Naval Research, which has spent $500,000 on the project
so far. "The endurance is measured in months rather than hours or
days."
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- The Flying Wing isn't the first glider to "fly"
underwater, just the first of its kind. Over the past seven years, projects
at the Scripps Institution of Oceanography, the University of Washington
School of Oceanography and Woods Hole Oceanographic Institution have developed
gliders whose designs incorporate torpedo-like shapes. The new wing design,
akin to that of a B-2 stealth bomber, could be superior to them in some
ways but inferior in others, sources said.
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- New craft based on the flying-wing prototype, which has
a 20-foot wingspan and a theoretical top speed of 5 nautical mph -- 10
times the speed of existing gliders -- might be effective in the open sea,
but their size could hinder them in shallow waters and make them more difficult
to deploy than existing gliders.
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- The Flying Wing Underwater Glider's likely civilian applications
include ocean science research, environmental study and fisheries monitoring,
Swean said. It could map currents or follow marine animals without disrupting
their behavior, according to Scott Jenkins, a senior engineer at Scripps
who spearheaded work on the glider's design.
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- Jenkins described two scenarios in which the glider could
play a vital role. In the first, oil companies use it to monitor the activity
of sperm whales. The industry's use of seismic refraction shootings to
detect undersea oil deposits -- explosions are detonated and the resulting
shock waves are studied -- is restricted when whales are nearby. In the
second scenario, a glider monitors an offshore waste field to help determine
its relationship to beach closures.
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- "Nothing else is capable of doing that (kind of
research) in an economical way," he said, pointing out that the use
of ships is expensive, whether data gathering is carried out onboard or
the ship is hired as a delivery vehicle for instruments on moorings. Moorings
are susceptible to damage from storms, ship collisions and vandalism.
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- The glider's other major applications are military, Swean
said. They include surveillance and reconnaissance. "Homeland security
applications would involve coastal monitoring, perhaps ship traffic,"
he added.
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- In the future, gliders could take on other roles, such
as payload delivery. "We're talking very large gliders," Jenkins
said. "One practical thing would be to move underwater robots (vehicles)
around. All of those devices have a mother vehicle. A glider could do it
in a very clandestine way."
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- The Navy's tests scheduled for March will take place
in a vast basin at Space and Naval Warfare Systems Center in San Diego.
Tests scheduled for April will take place at sea off Point Loma, which
lies between San Diego Bay and the Pacific Ocean. Precise test dates have
yet to be determined, but the goals are clear.
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- "These are basic tests to validate hydrodynamic
design," Swean said. "We will observe glide trajectory at a prescribed
net buoyancy to confirm the wing is flying as designed. Subsequent phases
will integrate sensors and prove endurance (and) range."
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- The prototype wing, built by Legnos Boat Building of
Groton, Connecticut, is 1.3 feet thick and made up of fiberglass covering
foam ribs, Swean said. Inside the glider, a steel pressure hull will protect
inner workings during deep-sea diving, Jenkins added. The internal volume
of 40 cubic feet will be enough space for control systems and research
instruments.
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- The most essential control system is the buoyancy engine,
which uses battery power to drive the wing, Jenkins said. It powers a high-pressure
pump that inflates a bladder, which displaces enough water to cause the
glider to rise. Evacuating the bladder displaces less water and causes
the glider to descend.
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- As Swean described it, the wing moves forward when changes
in its buoyancy create vertical forces; the wing uses the pressure of the
water's mass to transform those forces into forward movement. In other
words, it moves forward by changing its elevation. Jenkins added that the
onboard computer will adjust the craft's center of gravity by sliding the
batteries along a track, which will also help with steering.
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- The new design's potential superiority over existing
underwater gliders involves the efficiency of the wing shape, Jenkins said.
With nearly all of the surface area creating lift, the vehicle can travel
over long distances using only a small amount of energy.
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- "The wing is the most efficient shape we know,"
Jenkins said. "The prototype for it is a bird. Nature's the most demanding
of all engineers."
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- The glider will surface to transmit data to a satellite
or stay submerged to send acoustic communications, Swean said.
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- The Navy isn't the only party interested in the outcome
of the flying-wing glider tests.
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- "We will certainly follow what Scott (Jenkins) has
done and look into the capabilities of that (glider)," said Clayton
Jones, a project engineer with glider manufacturer Webb Research.
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