Liberdade class blended wing bodies are autonomous underwater gliders developed by the US Navy

Office of Naval Research The Office of Naval Research (ONR) is an organization within the United States Department of the Navy responsible for the science and technology programs of the U.S. Navy and Marine Corps. Established by Congress in 1946, its mission is to plan ...

which use a blended wing body hullform to achieve hydrodynamic efficiency. It is an experimental class whose models were originally intended to track quiet

diesel electric Diesel may refer to: * Diesel engine, an internal combustion engine where ignition is caused by compression * Diesel fuel, a liquid fuel used in diesel engines * Diesel locomotive, a railway locomotive in which the prime mover is a diesel engine ...

submarines in

littoral The littoral zone or nearshore is the part of a sea, lake, or river that is close to the shore. In coastal ecology, the littoral zone includes the intertidal zone extending from the high water mark (which is rarely inundated), to coastal areas ...

waters, move at 1–3 knots and remain on station for up to six months. The "Liberdade" (Portuguese for "Liberty") was the name of a ship built by

Joshua Slocum Joshua Slocum (February 20, 1844 – on or shortly after November 14, 1909) was the first person to sail single-handedly around the world. He was a Nova Scotian-born, naturalised American seaman and adventurer, and a noted writer. In 1900 he wr ...

prior to the one he single-handedly piloted around the world. Members of the Liberdade class are the world's largest known underwater gliders and were developed as part of the US Navy's Persistent Littoral Undersea Surveillance Network (PlusNet) system of unmanned surveillance vehicles. The gliders can be deployed covertly with the capability of monitoring over 1000 km of ocean. The glider is designed to be difficult to detect using passive acoustic sensing. The Marine Physical Lab at

Scripps Institution of Oceanography The Scripps Institution of Oceanography (sometimes referred to as SIO, Scripps Oceanography, or Scripps) in San Diego, California, US founded in 1903, is one of the oldest and largest centers for oceanography, ocean and Earth science research ...

, and the Applied Physics Lab at the

University of Washington The University of Washington (UW, simply Washington, or informally U-Dub) is a public research university in Seattle, Washington. Founded in 1861, Washington is one of the oldest universities on the West Coast; it was established in Seattle a ...

are the primary developers of the Liberdade class. The hull of the latest model was constructed by Legnos Boat, and consists of an ABS outer shell over a titanium frame. First major field tests of the Liberdade XRay took place in 2006 in

Monterey Bay, California Monterey Bay is a bay of the Pacific Ocean located on the coast of the U.S. state of California, south of the San Francisco Bay Area and its major city at the south of the bay, San Jose. San Francisco itself is further north along the coast, by a ...

. Also participating in the development of the Liberdade class wings were: *

University of Texas at Austin The University of Texas at Austin (UT Austin, UT, or Texas) is a public research university in Austin, Texas. It was founded in 1883 and is the oldest institution in the University of Texas System. With 40,916 undergraduate students, 11,075 ...

’s Applied Research Lab *Applied Research Lab at

Penn State University The Pennsylvania State University (Penn State or PSU) is a public state-related land-grant research university with campuses and facilities throughout Pennsylvania. Founded in 1855 as the Farmers' High School of Pennsylvania, Penn State became ...

Massachusetts Institute of Technology The Massachusetts Institute of Technology (MIT) is a private land-grant research university in Cambridge, Massachusetts. Established in 1861, MIT has played a key role in the development of modern technology and science, and is one of the ...

Woods Hole Oceanographic Institution The Woods Hole Oceanographic Institution (WHOI, acronym pronounced ) is a private, nonprofit research and higher education facility dedicated to the study of marine science and engineering. Established in 1930 in Woods Hole, Massachusetts, it i ...

* SAIC *

Bluefin Robotics Bluefin Robotics is an American robotics company, headquartered in Quincy, Massachusetts, which specialises in the design and manufacture of military and civilian autonomous underwater vehicles (AUVs) and related technology. The company was foun ...

In 2007, XRay 2 was completed and demonstrated a 20 to 1 lift-to-drag ratio. In 2008, 55 field tests were conducted. In 2010, the latest generation "ZRay" model was completed and includes a 27 channel hydrophone array. Its goal is to track and automatically identify marine mammals. ZRay has a 35 to 1 lift-to-drag ratio,{{dead link, date=December 2017 , bot=InternetArchiveBot , fix-attempted=yes and has water jets for fine attitude control, as well as propulsion on the surface.

References

Underwater gliders Anti-submarine warfare