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Article: Birds' tails do act like delta wings but delta-wing theory does not always predict the forces they generate

TitleBirds' tails do act like delta wings but delta-wing theory does not always predict the forces they generate
Authors
KeywordsDelta-wing theory
Birds' tails
Bird flight
Aerodynamics
Issue Date2003
Citation
Proceedings of the Royal Society B: Biological Sciences, 2003, v. 270, n. 1522, p. 1379-1385 How to Cite?
AbstractDelta-wing theory, which predicts the aerodynamics of aircraft like the Concorde, is the conventional explanation for the way in which a bird's tail operates in flight. Recently, doubt has been cast on the validity of applying a theory devised for supersonic aircraft to the small tails of slow-flying birds. By testing delta-wing models and birds' tails behind bodies with wings, I empirically show that the tails of birds produce lift in a very similar way to conventional delta-wing models. Both Perspex and birds' tail models produce lift similar to that predicted by delta-wing theory when narrowly spread and at low angles of attack. However, when widely spread and at high angles of attack, both tails and Perspex models produce much less lift than predicted, owing to vortex breakdown after which the assumptions of delta-wing theory are violated. These results indicate that birds' tails can be regarded as delta wings but that the theory predicting the forces produced by delta wings can only be applied within acceptable limits (i.e. tails spread less than 60° and at angles of attack of less than 20°).
Persistent Identifierhttp://hdl.handle.net/10722/230722
ISSN
2015 Impact Factor: 4.823
2015 SCImago Journal Rankings: 2.375

 

DC FieldValueLanguage
dc.contributor.authorEvans, Matthew R.-
dc.date.accessioned2016-09-01T06:06:38Z-
dc.date.available2016-09-01T06:06:38Z-
dc.date.issued2003-
dc.identifier.citationProceedings of the Royal Society B: Biological Sciences, 2003, v. 270, n. 1522, p. 1379-1385-
dc.identifier.issn0962-8452-
dc.identifier.urihttp://hdl.handle.net/10722/230722-
dc.description.abstractDelta-wing theory, which predicts the aerodynamics of aircraft like the Concorde, is the conventional explanation for the way in which a bird's tail operates in flight. Recently, doubt has been cast on the validity of applying a theory devised for supersonic aircraft to the small tails of slow-flying birds. By testing delta-wing models and birds' tails behind bodies with wings, I empirically show that the tails of birds produce lift in a very similar way to conventional delta-wing models. Both Perspex and birds' tail models produce lift similar to that predicted by delta-wing theory when narrowly spread and at low angles of attack. However, when widely spread and at high angles of attack, both tails and Perspex models produce much less lift than predicted, owing to vortex breakdown after which the assumptions of delta-wing theory are violated. These results indicate that birds' tails can be regarded as delta wings but that the theory predicting the forces produced by delta wings can only be applied within acceptable limits (i.e. tails spread less than 60° and at angles of attack of less than 20°).-
dc.languageeng-
dc.relation.ispartofProceedings of the Royal Society B: Biological Sciences-
dc.subjectDelta-wing theory-
dc.subjectBirds' tails-
dc.subjectBird flight-
dc.subjectAerodynamics-
dc.titleBirds' tails do act like delta wings but delta-wing theory does not always predict the forces they generate-
dc.typeArticle-
dc.description.natureLink_to_subscribed_fulltext-
dc.identifier.doi10.1098/rspb.2003.2373-
dc.identifier.pmid12965029-
dc.identifier.scopuseid_2-s2.0-0038639745-
dc.identifier.volume270-
dc.identifier.issue1522-
dc.identifier.spage1379-
dc.identifier.epage1385-
dc.identifier.eissn1471-2970-

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