Birds, Bats And Insects Hold Secrets For Aerospace Engineers

Daily Science Journal (Feb. 9, 2008) — Natural flyers like birds, bats and insects outperform man-made aircraft in aerobatics and efficiency. University of Michigan engineers are studying these animals as a step toward designing flapping-wing planes with wingspans smaller than a deck of playing cards.

Flapping flight is inherently unsteady, but that's why it works so well. Birds, bats and insects fly in a messy environment full of gusts traveling at speeds similar to their own. Yet they can react almost instantaneously and adapt with their flexible wings. (Credit: iStockphoto/Steve Byland)

A Blackbird jet flying nearly 2,000 miles per hour covers 32 body lengths per second. But a common pigeon flying at 50 miles per hour covers 75. The roll rate of the aerobatic A-4 Skyhawk plane is about 720 degrees per second. The roll rate of a barn swallow exceeds 5,000 degrees per second.

Select military aircraft can withstand gravitational forces of 8-10 G. Many birds routinely experience positive G-forces greater than 10 G and up to 14 G.

“Natural flyers obviously have some highly varied mechanical properties that we really have not incorporated in engineering,” said Wei Shyy, chair of the Aerospace Engineering department and an author of the new book “The Aerodynamics of Low Reynolds Number Flyers.”

“They’re not only lighter, but also have much more adaptive structures as well as capabilities of integrating aerodynamics with wing and body shapes, which change all the time,” Shyy said. “Natural flyers have outstanding capabilities to remain airborne through wind gusts, rain, and snow.” Shyy photographs birds to help him understand their aerodynamics.

Pressure generated during flight cause the flapping wings to deform, he explained. In turn, the deformed wing tells the air that the wing shape is different than it appears in still air. If appropriately handled, this phenomenon can delay stall, enhance stability and increase thrust.

Flapping flight is inherently unsteady, but that’s why it works so well. Birds, bats and insects fly in a messy environment full of gusts traveling at speeds similar to their own. Yet they can react almost instantaneously and adapt with their flexible wings.

Shyy and his colleagues have several grants from the Air Force totaling more than $1 million a year to research small flapping wing aircraft. Such aircraft would fly slower than their fixed wing counterparts, and more importantly, they would be able to hover and possibly perch in order to monitor the environment or a hostile area. Shyy’s current focus is on the aerodynamics of flexible wings related to micro air vehicles with wingspans between 1 and 3 inches.

“These days, if you want to design a flapping wing vehicle, you could build one with trial and error, but in a controlled environment with no wind gusts,” Shyy said. “We are trying to figure out how to design a vehicle that can perform a mission in an uncertain environment. When the wind blows, how do they stay on course?”

A dragonfly, Shyy says, has remarkable resilience to wind, considering how light it is. The professor chalks that up to its wing structure and flight control. But the details are still questions.

“We’re really just at the beginning of this,” Shyy said.

Shyy is the Clarence L. "Kelly" Johnson Collegiate Professor of Aerospace Engineering. Other authors of the book, “Aerodynamics of Low Reynolds Number Flyers” are: U-M research scientists Yongsheng Lian, Jian Tang and Dragos Viieru, and Hao Liu, professor of Biomechanical Engineering at Chiba University in Japan.

Other collaborators on this research include professors Luis Bernal, Carlos Cesnik and Peretz Friedmann of the University of Michigan; Hao Liu of Chiba University in Japan; Peter Ifju, Rick Lind and Larry Ukeiley of University of Florida, and Sean Humbert of University of Maryland.

Adapted from materials provided by University of Michigan.

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Oiled-bird Being Rescued In San Francisco

Daily Science Journal (Nov. 12, 2007) — UC Davis wildlife experts are leading the rescue of oiled birds in San Francisco today after a container ship spilled nearly 60,000 gallons of heavy bunker fuel oil into the bay.

Veterinarians assess the health status of oiled birds that are being brought in from beaches and the bay waters. (Credit: UC Davis (archival photo))

Three veterinarians and a veterinary technician arrived at Fort Mason Wednesday to organize the rescue effort and begin treating injured birds.

By 1 p.m. November 8, there were 21 seabirds being treated, all of them surf scoters, according to UC Davis veterinarian Michael Ziccardi, director of the California Oiled Wildlife Care Network.

Jonna Mazet, a UC Davis veterinarian and international authority on the rescue and treatment of oiled wildlife, has said in the past that for every oiled seabird that is found washed ashore, an estimated 10 to 100 birds died at sea.

The UC Davis rescue team is working in a custom-built recovery and rehabilitation trailer. There, they assess the health status of oiled birds that are being brought in from beaches and the bay waters.

Then the birds are put in boxes and driven to the San Francisco Bay Oiled Wildlife Care and Education Center in Cordelia (just outside Fairfield), where they will receive the world's most advanced veterinary care for oiled wildlife.

At the center, the first order of business is not to remove oil from the birds. Instead, it is to warm the birds and nourish them. Once stabilized, they will be better able to withstand the stresses of being washed.

The Cordelia center is a 12,000-square-foot, $2.7 million facility capable of caring for up to 1,000 sick birds. It is the major Northern California rescue center in the statewide Oiled Wildlife Care Network, which comprises nine rescue facilities and 25 organizations prepared to care for oiled wildlife on short notice.

At each California rescue center, UC Davis wildlife veterinarians work in partnership with local, trained wildlife rehabilitators. At the Cordelia center, those rehabilitators are staff members of the International Bird Rescue Research Center.

At this time, a standing corps of trained volunteers is being called up to staff the rescue center.

The Oiled Wildlife Care Network is managed statewide by the UC Davis Wildlife Health Center, a unit of the UC Davis School of Veterinary Medicine.

The network is funded by the Office of Spill Prevention and Response of the California Department of Fish and Game. The Fish and Game monies come from interest on the $50 million California Oil Spill Response Trust Fund, built from assessments on the oil industry.

In addition to giving veterinary care, the network funds basic research into the effects of oil on wildlife and applied research into treatments that will improve survival.

Adapted from materials provided by University of California, Davis.

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Satellite Tracking Will Help Answer Questions About Penguin Travels

Daily Science Journal (Aug. 10, 2007) — You could understand if a half-dozen Magellanic penguins developed a "big bird is watching" phobia before this month is over, but the surveillance really will be for their own good.

The feathers of three Magellanic penguins blackened with oil, seen along Argentina's Atlantic coast in October 2005. (Credit: Dee Boersma)

University of Washington scientists will attach satellite tracking devices to the backs of six penguins that have been treated at two centers in northern Argentina after their feathers were fouled with oil. The birds will be released into the Atlantic Ocean and their movements traced using satellites and the Internet.

The idea is to plug a critical gap in the knowledge of the Magellanics' annual life cycle, their movements on the journey from their winter feeding grounds back to their breeding colonies along the southern Argentina coast and the Islas Malvinas, or Falkland Islands.

"We're missing that information. We know what happens when they leave the breeding grounds but we don't know what happens on the return trip," said Elizabeth Skewgar, a University of Washington doctoral student in biology.

"We want to model the energy requirements for these birds so that we understand what it takes to return to the breeding grounds and still have enough energy to reproduce. Human fisheries competing for the same food could make migration even more difficult for them."

The project is led by Dee Boersma, a UW biology professor who for 25 years has headed the Magellanic Penguin Project at Punta Tombo, Argentina, the birds' largest breeding colony in South America.

"We need to know how penguins use the ocean so we can make their migration route safe through a combination of national marine parks, marine protected areas and ocean zoning," Boersma said.

During the week of Aug. 20, the scientists will select six adult male penguins from rehabilitation centers at San Clemente del Tuyu and Mar del Plata, coastal towns more than 500 miles north of Punta Tombo. Epoxy and special tape will be used to attach a transmitter to each bird before it is released into the Atlantic. The tags are about the size of many common cellular telephones and weigh less than 3.5 ounces.

"We want to put the transmitters on healthy, robust birds that we think are likely to get back and start breeding," Boersma said. "The point is to follow them back to their colony and see where they might be running into petroleum."

Through late October the birds' movements will be tracked by the Argos satellite system, operated by the National Oceanic and Atmospheric Administration and the French space agency. A satellite will pass overhead every two hours and chart the penguins' positions, then transmit the information back to the researchers, who will use it to update a public tracking map on the Internet at http://www.penguinstudies.org.

The transmitters will be active for 36 hours at a time and then will be off for 36 hours, a means of preserving the two double-A batteries in each transmitter for the life of the project. The researchers have no way of knowing whether the birds will go to southern Argentina or the Malvinas, or whether they will follow a straight course to the breeding grounds or take a circuitous route.

"After we release them, they could just hang out at Mar del Plata for a month. It's all up to them," Boersma said. "We're hoping the males we tag will be in a hurry to get to their colony and start breeding."

The satellite tracking also will be instrumental in pinpointing the birds after they arrive at the breeding grounds. Punta Tombo alone is home to some 400,000 penguins during breeding season.

"Tracking the locations by satellite is only accurate to within 5 kilometers, so it really is like trying to find a needle in a haystack," Boersma said.

Locating the penguins once they reach the breeding ground is important so the researchers can assess the birds' physical condition after the long journey.

"We'll know how much weight they gained or lost on their journey," Boersma said.

After its mate arrives, a male fasts until the female lays two eggs, then he returns to the ocean to feed, sometimes swimming hundreds of miles in search of fish such as anchovies that are staples of the penguin diet. After about two weeks the male returns to the nest to incubate the eggs while the female goes in search of food.

The birds' energy can be drastically sapped if they become coated with oil, and that can mean death. Last year, a team of scientists that included Boersma reported they had found 19 groups rehabilitating oiled seabirds along the Atlantic coast from central Brazil to central Argentina, indicating a much larger problem than generally had been believed. It remains uncertain where the oil comes from -- it could be from a combination of sources, including seepage from offshore oil rigs and ballast water from passing ships.

"We know that birds show up oiled back at our colony, so that means they're getting oiled somewhere between where they winter and Punta Tombo," Boersma said.

Others involved in the work are Sergio Rodriguez Heredia of the Fundacion Mundo Marino in San Clemente del Tuyu, Karen Griot of Fundacion Mar del Plata Aquarium and Valeria Ruoppolo of the International Fund for Animal Welfare's Penguin Network.

The research will be included in Skewgar's doctoral dissertation. The work is being funded by the Wildlife Conservation Society, with support from the tourism office of the Argentine Province of Chubut.

Adapted from materials provided by University of Washington.

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