V formation
A V formation is a symmetric
Flying in the V formation likely improves energy efficiency. Usually, large birds fly in this formation since smaller birds create more complex wind currents that are hard for the back members to take advantage of.[1] V formations also improve the fuel efficiency of aircraft.
Aerodynamics
The V formation possibly improves the efficiency of flying birds, particularly over long
Previous studies found that birds can use less than 20 to 30 percent of energy. According to a 1970 paper, in a V formation of 25 members, each bird can achieve a reduction of
Flight characteristics
In a V formation, some birds prefer to fly at the left, some at the right, and some at the center.
Flying in V formation is not only about position but also about the timing of flapping. The birds behind will sync with the flapping pattern of the leading bird to follow the trail of
Through an experiment with ibises, researchers found that flying in V formation is a skill that they were not born with.[6] When they first flew together, they did not fly in a V shape. However, over time, they started learning how to fly in this formation as if they were self-taught or they learned by observing other ibises.
Applications
Military flight
The "V", or
Similar aerodynamics advantage was attempted to be utilized by engineers and research pilots. The airflow from wingtips of the aircraft can provide upward lift force for the planes behind, providing more efficient flight. NASA’s
Air Mobility Command, which accounts for 20 percent of all avionic fuel usage by the United States federal government, is also experimenting with autopilot changes to find the best tradeoff between the reduced drag of 'vortex surfing' and the resulting 'ride qualities' of flying through another aircraft's wake.[9][10]
Commercial flight
Airbus has made efforts to reduce fuel consumption in commercial aviation through its fello’fly project,[11] where two commercial aircraft fly in a V formation. Since large aircraft at high speed generate immense vortices at their wings, two aircraft will fly approximately 1.5 to 2 miles apart, near the smooth current of updraft. Thus, significant fuel can be saved without compromising passenger comfort.
Test flights were done using two AS350 Écureuil helicopters, and the results showed that 5 percent to 10 percent of fuel can be reduced for the second aircraft per trip. This percentage per flight means several tons of jet fuel and carbon dioxide emissions.[11] Nevertheless, operational and financial concerns and savings between airlines need to be addressed, as well as the schedules of position and altitude data for planes with similar routes to fly together.[11]
Birds that fly in V formation
This list is not comprehensive as it does not cover all birds that fly in V formation.[12]
Past studies and findings
- Wieselsberger (1914): An aerodynamicist who was the first to suggest that a formation may give birds an aerodynamic advantage. From the principles of aerodynamics, he knew that birds generate Bernoulli lift because of the upwash and downwash at the edges of their wings. He proposed that birds flying in a V formation make use of the upwash of neighboring birds to reduce induced drag, and hence conserve energy in flight.[13][14]
- Hamilton (1967): Posited that the staggered formation provides an advantage for visual communication with neighboring birds. At the same time, it also provides a clear viewing field during flight.[15][14]
- Lissaman & Schollenberger (1970): Conducted experiments to give a quantitative approximation of the energy saved. Through their study, they concluded that a formation of 25 birds can increase the birds' range by up to 71% as compared to just one bird.[4]
- Willis et al. (2007): Sought to examine the energy savings in flight with respect to positioning and wing beat phase relationships between two adjacent birds. The results showed that optimal flapping of each bird accounts for up to 20% energy savings.[16]
References
- ^ a b c d e Waldron, Patricia (2014-01-15). "Why Birds Fly in a V Formation". Science. AAAS. Retrieved 2021-03-14.
- ^ USA Today: "Why birds fly in a V-formation" by Traci Watson January 15, 2014
- ^ "Fly like a bird: The V formation finally explained". BBC News. 2014-01-16. Retrieved 2021-03-14.
- ^ a b Lissaman, P.B.S. & Shollenberger, C.A. (1970). Formation flight of birds. Science 168(3934): 1003–1005 (same on JSTOR)
- ^ "Why do geese fly in a V?". Library of Congress. Retrieved 2021-03-14.
- ^ a b "Birds That Fly in a V Formation Use An Amazing Trick". Science. 2014-01-15. Archived from the original on February 22, 2021. Retrieved 2021-03-14.
- ^ "Oxford Dictionary: Skein". Archived from the original on January 7, 2019. Retrieved 6 January 2019.
- ^ a b "NASA - Dryden Flight Research Center - News Room: News Releases: NASA'S AUTONOMOUS FORMATION FLIGHT: FOLLOW THE LEADER AND SAVE FUEL". www.nasa.gov. Retrieved 2021-03-14.
- ^ Drinnon, Roger. "'Vortex surfing' could be revolutionary." Air Mobility Command, 10 October 2012.
- ^ Warwick, Graham. "C-17 s Go Surfing, to Save Fuel." Aviation Week, 12 October 2012.
- ^ a b c Howard Slutsken. "Why passenger jets could soon be flying in formation". CNN. Retrieved 2021-03-14.
- ISBN 978-0-12-517367-4, retrieved 2021-03-14
- ^ Wieselsberger, Carl. "Beitrag zur Erklarung des Winkelfluges eineger Zugvogel, Z. Flugtechnik &." Motorluftschiffahrt 5 (1914): 225-229.
- ^ S2CID 53180059.
- ^ Hamilton, W. J. (1967). Social aspects of bird orientation mechanisms. Animal orientation and navigation, 57-71.
- ^ Willis, D., Peraire, J., & Breuer, K. (2007). A computational investigation of bio-inspired formation flight and ground effect. In 25th AIAA Applied Aerodynamics Conference (p. 4182).
Bibliography
- Holmes, Tony. Spitfire vs Bf 109: Battle of Britain. Oxford, UK/ New York: Osprey, 2007. ISBN 1-84603-190-7.
External links
Migrating birds real flight V-formation spatial configuration. Real Dataset from North German bird migration photo).
Media related to V formations at Wikimedia Commons