V formation

A V formation is the symmetric V-shaped flight formation of flights of geese, swans, ducks, and other migratory birds, improving their energy efficiency. V formations also improve the fuel efficiency of aircraft and are used on military flight missions.

This article is about the flight formation of birds. For the military aircraft formation, see Vic formation.
Eurasian cranes in a V formation.

Aerodynamics

The V formation possibly improves the efficiency of flying birds, particularly over long migratory routes.[1] All the birds except the first fly in the upwash from one of the wingtip vortices of the bird ahead. The upwash assists each bird in supporting its own weight in flight, in the same way a glider can climb or maintain height indefinitely in rising air. According to a 1970 paper, in a V formation of 25 members, each bird can achieve a reduction of induced drag and as a result increase their range by 71%.[2] The birds flying at the tips and at the front are rotated in a timely cyclical fashion to spread flight fatigue equally among the flock members. Canada geese, ducks and swans commonly form a skein in V formation.[3]

Military flight missions
Main article: Vic formation
USAF F-15s over Alaska.

The "V", or "Vic" formation is a basic flight formation for military aircraft in many air forces. The Vic formation is also common in ceremonial flyovers and airshow flights.

Modern aerobatics team in formation

Air Mobility Command, which accounts for 20 percent of all avionic fuel usage by the United States federal government, is 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.[4][5]

gollark: > As opposite extreme you could have a country with a super strict and specific constitution that is too holy for any politician to change (maybe a theocracy) but the gov controls most of the industryThe *government* still has a lot of political power inasmuch as it controls lots of things.
gollark: No planet, so... ageoism?
gollark: Conversely, if you control a lot of what people do you control a lot of the flow of money.
gollark: If you control a large amount of the flow of money in a country, you also control a lot of what people do.
gollark: They are VERY RELATED, though, and your unrealistic example doesn't change that.

References
  1. USA Today: "Why birds fly in a V-formation" by Traci Watson January 15, 2014
  2. Lissaman, P.B.S. & Shollenberger, C.A. (1970). Formation flight of birds. Science 168(3934): 1003–1005 (same on JSTOR)
  3. "Oxford Dictionary: Skein". Retrieved 6 January 2019.
  4. Drinnon, Roger. "'Vortex surfing' could be revolutionary." Air Mobility Command, 10 October 2012.
  5. Warwick, Graham. "C-17 s Go Surfing, to Save Fuel." Aviation Week, 12 October 2012.

Bibliography
  • Holmes, Tony. Spitfire vs Bf 109: Battle of Britain. Oxford, UK/ New York: Osprey, 2007. ISBN 1-84603-190-7.

Media related to V formations at Wikimedia Commons

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