Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors

J.W. Kruyt, E.M. Quicazan-Rubio, G.J.F. van Heijst, D.L. Altshuler, D. Lentink

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

46 Citaties (Scopus)

Uittreksel

Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Previous quasi-steady experiments with a wing spinner set-up provide no support for this prediction. To test this more carefully, we compare the quasi-steady hover performance of 26 wings, from 12 hummingbird taxa. We spun the wings at angular velocities and angles of attack that are representative for every species and measured lift and torque more precisely. The power (aerodynamic torque × angular velocity) required to lift weight depends on aerodynamic efficacy, which is measured by the power factor. Our comparative analysis shows that AR has a modest influence on lift and drag forces, as reported earlier, but interspecific differences in power factor are large. During the downstroke, the power required to hover decreases for larger AR wings at the angles of attack at which hummingbirds flap their wings (p < 0.05). Quantitative flow visualization demonstrates that variation in hover power among hummingbird wings is driven by similar stable leading edge vortices that delay stall during the down- and upstroke. A side-by-side aerodynamic performance comparison of hummingbird wings and an advanced micro helicopter rotor shows that they are remarkably similar.
TaalEngels
Pagina's1-12
TijdschriftJournal of Royal Society Interface
Volume11
Nummer van het tijdschrift99
DOI's
StatusGepubliceerd - 2014

Vingerafdruk

Helicopter rotors
Aircraft
Aspect ratio
Torque
Aerodynamics
Angular velocity
Angle of attack
Birds
Power (Psychology)
Flow visualization
Weights and Measures
Costs and Cost Analysis
Helicopters
Drag
Vortex flow

Citeer dit

Kruyt, J.W. ; Quicazan-Rubio, E.M. ; van Heijst, G.J.F. ; Altshuler, D.L. ; Lentink, D./ Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors. In: Journal of Royal Society Interface. 2014 ; Vol. 11, Nr. 99. blz. 1-12
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abstract = "Hummingbirds are the only birds that can sustain hovering. This unique flight behaviour comes, however, at high energetic cost. Based on helicopter and aeroplane design theory, we expect that hummingbird wing aspect ratio (AR), which ranges from about 3.0 to 4.5, determines aerodynamic efficacy. Previous quasi-steady experiments with a wing spinner set-up provide no support for this prediction. To test this more carefully, we compare the quasi-steady hover performance of 26 wings, from 12 hummingbird taxa. We spun the wings at angular velocities and angles of attack that are representative for every species and measured lift and torque more precisely. The power (aerodynamic torque × angular velocity) required to lift weight depends on aerodynamic efficacy, which is measured by the power factor. Our comparative analysis shows that AR has a modest influence on lift and drag forces, as reported earlier, but interspecific differences in power factor are large. During the downstroke, the power required to hover decreases for larger AR wings at the angles of attack at which hummingbirds flap their wings (p < 0.05). Quantitative flow visualization demonstrates that variation in hover power among hummingbird wings is driven by similar stable leading edge vortices that delay stall during the down- and upstroke. A side-by-side aerodynamic performance comparison of hummingbird wings and an advanced micro helicopter rotor shows that they are remarkably similar.",
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Hummingbird wing efficacy depends on aspect ratio and compares with helicopter rotors. / Kruyt, J.W.; Quicazan-Rubio, E.M.; van Heijst, G.J.F.; Altshuler, D.L.; Lentink, D.

In: Journal of Royal Society Interface, Vol. 11, Nr. 99, 2014, blz. 1-12.

Onderzoeksoutput: Bijdrage aan tijdschriftTijdschriftartikelAcademicpeer review

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