Mil Tech — Small Robotic Flying Device Mimics Jellyfish

Aug 06 2015

Published by under Technology

A researcher at New York University’s Courant Institute has developed a small flying robotic device that takes its motion from that which a jellyfish does to move itself through water.


Leif Ristroph, assistant professor of mathematics at Courant Institute at New York University, says the device was developed as part of his Applied Mathematics Laboratory’s continuing work on understanding unsteady aerodynamics and fluid structure interactions.

“We didn’t officially name our robot, though we call it a ‘flying jellyfish,’ ” Ristroph says. “Maybe ‘aerojelly’ would be a nice name.”

Ristroph says the flyer is an ornithopter, or flapping wing aircraft, about 4 inches in size, that fits in a person’s hand.

“The concept is to have a membrane or set of wings that close and open somewhat like a jellyfish closes and opens its bell,” he points out. “Our specific realization has four wings hinged from above and driven by a motor to collapse inward and then outward, squeezing air downward to generate an upward lift. It flaps these wings about 20 times each second in flight, so it appears as a blur to the eye.”

While the flying robot resembles a jellyfish’s action through water, its inspiration didn’t come from jellyfish but rather a set of experiments Ristroph and his researchers previously had done.

“These involved pyramid shapes that can hover when placed upright in a vertically oscillating airflow,” Ristroph says. “These earlier experiments involved an externally driven flow, provided by a loudspeaker. The idea behind our flyer was to have the relative motion between the wings and air driven by an on-board motor so that it can fly in open air.”

Thus far with the current version of the flying jellyfish, the researchers have not managed to get a battery on board. Its power is wired in through tiny copper wires connected to a direct current power supply, which allows the flyer to flit about in a one meter cubic volume, enough to study its flight dynamics and stability but not good enough for practical applications yet.

Ristroph notes the first prototype of the flying jellyfish is very simple.

“It does not carry anything other than the mechanical components needed for flight, like wings, transmission system, motor, and body frame,” he says. “One very nice thing we found is that the flyer does not need any sensors to keep upright during flight — it has so-called passive upright stability, which is a great convenience when we think about further miniaturization of such a design. No special stabilizing tails or other surfaces are needed, and no sensors and computers are needed either.”

Ristroph says he has received questions and comments from individuals associated with the U.S. Air Force but no officially-expressed military interest yet.

“We aren’t working with anyone right now, though we are filing a patent through New York University, which is interested in developing the flyer further,” he says. “There are some engineering hurdles — especially getting a battery on board — that we as physicists and mathematicians will have to rely on others to overcome.”

Ristroph hopes that the help of engineers will take his tethered prototype to the level of a free-flying, self-powered machine. In addition, he believes more study on what makes the flyer so self-stable is another interesting point to figure out.

“This is especially interesting, since we now know that the way insects fly is not passively stable, bur rather they rely on sensors and feedback control to keep upright,” he notes. It’s an exciting time for individuals involved in trying to build small-scale flying machines, especially unorthodox versions like those with flapping wings. Any one of their ideas might just be a significant advance.”

About the author: Alan M. Petrillo is a Tucson, Ariz., journalist who writes for national and regional magazines and newspapers. He’s the author of several books on historical military firearms; and two historical mysteries, Full Moon, and his latest novel, Asylum Lane, all available at

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Mil Tech — Autonomous Underwater Vehicle Swims Like a Fish

Jul 09 2015

Published by under Technology

The manner in which fish’s fins allow it to swim is the inspiration for the design of a unique underwater propulsion system being developed by the U.S. Naval Research Laboratory (NRL) in Arlington, Va.

WANDA, the Wrasse-inspired Agile Near-shore Deformable-Fin Automation, is a man-portable autonomous underwater vehicle (AUV) that uses two pairs of fish-like fins that allow it to conduct missions in littoral zones where low speed and high maneuverability are prized capabilities.

Jason Geder, aerospace engineer at the NRL’s Laboratories for Computational Physics and Fluid Dynamics, says WANDA was inspired by the pectoral fins of the reef fish, bird wrasse, and allowed NRL researchers to develop a vehicle with an actively controlled curvature robotic fin that provides scaled down AUVs with a low speed propulsion system.

“The actively controlled curvature fins allow the vehicle to maneuver more precisely than a propeller driven vehicle,” Geder points out. “Propeller systems have issues with dead zones and overshoot that WANDA does not.”

WANDA has two pairs of pectoral fins, two forward and two aft on the vehicle. Geder says WANDA’s uniqueness lies in the fact it actively controls the curvature of its fins by actuating individual rib bars within the fins, which allows it to swim through the water by an oscillating motion.

The current version of WANDA is 3-1/2 feet long with a nearly elliptical cross section that’s approximately 14 inches in width at its widest point and less than 10 inches at its highest point.

“The dry weight, depending on its payload, is approximately 25 pounds and can be picked up by a single person,” Geder says.

WANDA carries sensors on board for navigation, operation and maneuvering, relying on an inertial navigation system, angular rate gyros, accelerometers for measuring heading and the angle of the vehicle, a pressure sensor for measuring depth, and a GPS for fixing its location if it comes to the surface, Geder says.

Geder says NRL researchers have developed near-field pressure sensors that allow WANDA to detect current flows and static objects in the near field. “It’s like the lateral line sensors fish use to detect objects on their side and front,” he says. “The fish use a system of hair-like pressure sensing elements that allow them to sense changes in the flow field around their body. We are testing those kinds of sensors with WANDA for their navigational capabilities.”

WANDA’s modular construction allows it to be integrated for a number of different mission-specific payloads, Geder points out. “Besides the near-field sensors, we also are developing chemical sensors for detecting underwater chemical signatures in the environment, where they would detect a particular element and then use that information to navigate upstream to where it’s coming from,” he says. “If WANDA is close to the surface, it can communicate that information in real time by wireless data transfer and also store the data on board for later downloading.”

Geder says NRL has programmed a number of different maneuvers and missions into WANDA.

“These are closed loop maneuvers, where, for example, the vehicle would dive to a certain depth, do a certain pattern like a box or a lawnmower pattern, and then return to the surface to transfer the data,” Geder says. “It also has the capability for manual operation for testing purposes, where a user controls the vehicle.”

Geder says the next step in the development of WANDA is improving the vehicle’s robustness for field trials that will be conducted this summer in the Washington, D.C. area with a number of NRL collaborators.

About the author: Alan M. Petrillo is a Tucson, Ariz., journalist who writes for national and regional magazines and newspapers. He’s the author of several books on historical military firearms and two historical mysteries, Full Moon, and his latest novel, Asylum Lane, all available at

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Hurricane Season: 5 Steps to Prepare

Jun 04 2015

Published by under Health & Living

The Eastern Pacific hurricane season began May 15 and ends Nov. 30. Hurricane season in the Atlantic begins June 1 and ends Nov. 30. TRICARE advises beneficiaries to prepare by ensuring they not only have a good stash of emergency supplies but also plan ahead with their health in mind.

  1. Develop a disaster plan and choose a safe evacuation route.
  2. Make copies of all important documents, including your uniformed services ID card, and keep them in a waterproof container.
  3. Carry a copy of all important phone numbers, such as your primary or any specialty care providers.
  4. Keep an extra dose of medications and any needed medical devices or equipment.
  5. Arrange for help getting to a shelter.

The primary hazards from hurricanes are storm surge flooding, inland flooding from heavy rains, destructive winds, tornadoes, and high surf and rip currents. Storm surge is dangerous because a mere 6 inches of fast-moving floodwater can knock over an adult. As little as 2 feet of rushing water can carry away most vehicles — including large pickup trucks and SUVs.

Staying informed is also a major step in being prepared. Go to the Disaster Information page on the TRICARE website for more information on what to do before and after a disaster. You also can sign up to receive email or text disaster alerts directly to your phone. Simply choose your subscription type and enter your email address or mobile phone number.

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Mil Tech — Naval Research Laboratory Produces Transparent Armor-like Material

Jun 01 2015

Published by under Technology

The Naval Research Laboratory has made a transparent ceramic that can be used to armor lenses and face shields and in other applications.

The U.S. Naval Research Laboratory (NRL) has invented a special ceramic that looks like glass but is much harder, is tough like armor, and can be used on unmanned aerial vehicles, lenses, face shields and electronics protection.

Jas Sanghera, Ph.D, branch head of Optical Materials and Devices at the NRL, says  the material, spinel, goes back to the 1960s when researchers attempted to make it synthetically.

“The material is found in nature as a mineral in small sizes, but for practical applications, one needs material larger than a centimeter, which is not found in nature,” Sanghera says. “Researchers tried to pack spinel powder into a denser material through a pressing process known as sintering, and if one does it right, the process gets rid of the empty space, the porosity, and the material becomes clear. We were able to do that.”

Sanghera says that NRL scientists were able to use a solid state process to heat the spinel to 1,500 degrees Centigrade, which is well below its melting point of 2,000 degrees Centigrade.

“We use a hot press that applies pressure to the material like a piston would to plungers inside a tube,” he points out. “We elevate the temperature, evacuate the air and the material is allowed to densify. The trick is to get rid of all the entrapped air in the material, and if you do that right, the result is a clear looking material.”

The resulting product is thinner than glass but much stronger, Sanghera notes. The NRL has produced spinel that is up to 11/2-inches thick, but is able to make thinner sheets of the material because most applications require a covering less than one inch thick, typically around a half-inch or less.

“This really is a transparent armor-like material,” Sanghera observes. “We have demonstrated the feasibility and transitioned this technology to industry to enable fabrication of larger finished products in the 25-inch square size.”

Sanghera says the transparent armor likely could be used for platform protection purposes.

“When you have cameras that operate in visible and infrared, it’s nice to have a rugged window in front of them,” he says. “Protecting cameras and sensors in military hardware is an important application. Wherever you see glass, polycarbonate or plastic, those can be areas for replacement by this material.”

Sanghera notes  the strength of the transparent armor ranges by the size and shape of the finished material but that typically it is more than three-times stronger than glass of the same size.

“One of the areas of interest is replacing ballistic glass,” he says. “That’s a laminate of glass and plastic layers. The glass part of ballistic glass could be replaced with spinel, which would reduce the weight and thickness of the armor but give a greater strength.”

About the author: Alan M. Petrillo is a Tucson, Ariz., journalist who writes for national and regional magazines and newspapers. He’s the author of the historical mystery, Full Moon; the nonfiction work, Ice Hockey in the Desert; and his newest historical mystery, Asylum Lane, all available at

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PenFed Foundation’s 11th Annual Night of Heroes Gala

May 15 2015

PenFed Gala

The Pentagon Federal Credit Union Foundation (PenFed Foundation) recently celebrated its 11th annual Night of Heroes Gala, “Building the Future. Honoring the Past” by honoring retired General Gordon R. Sullivan, USA (Ret) and former Senator Elizabeth Dole. The event was held on May 14 to honor those who have set the example for supporting the military community, with a special tribute to those who served during the Vietnam era.

General Gordon R. Sullivan, USA (Ret), 32nd Chief of Staff of the United States Army and president and CEO of the Association of the United States Army, received the Military Hero Award. Elizabeth Dole, former U.S. Senator from North Carolina and founder of the Elizabeth Dole Foundation, received the Community Hero Award, and Betty Easley, the wife and caregiver of Army veteran Greg Easley, received the Hero at Home Award.

The gala attendees also included several notable guests, such as General George W. Casey, Jr., who served as the 36th Chief of Staff of the U.S. Army, R. James Nicholson, former Secretary of Veterans Affairs, Jake Tapper, anchor and chief Washington correspondent for CNN and Vice Admiral Norb Ryan, the president of MOAA.

The PenFed Foundation, founded in 2001, is a national nonprofit organization dedicated to serving the military community by promoting financial education. The foundation is affiliated with Pentagon Federal Credit Union. To learn more about the foundation and for donation opportunities, please visit

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