Today, Flapping Micro Aerial Vehicles (MAV) are used in many different applications. Reynolds Number for this kind of aerial vehicle is about 104 ~ 105 which shows dominancy of inertial effects in comparison of viscous effects in flow field except adjacent of the solid boundaries. Due to periodic flapping stroke, fluid flow is unsteady. In addition, these creatures have some complexities in kin...

Bat wings are important for thermoregulation, but their role in heat balance during flight is largely unknown. More than 80% of the energy consumed during flight generates heat as a by-product, and thus it is expected that bat wings should dissipate large amounts of heat to prevent hyperthermia. We measured rectal (T(r)) and surface (T(s)) temperatures of Brazilian free-tailed bats (Tadarida br...

—We analyzed diff erences in wing morphology between sexes and among age classes of Western Sandpipers (Calidris mauri) to assess possible relationships with diff erential migration, acrobatic aerial displays, and potential vulnerability to predation, using size-constrained component analysis. Data on wing morphology of all four sex and age classes were available from birds spending the nonbree...

Knives, birds' wings, and mountain slopes are used for certain purposes: cutting, flying, and climbing. A bird's wings have in common with knives that they have been 'designed' for the purpose they serve, which purpose accounts for their existence, whereas mountain slopes have come about by geological processes independently of their uses for climbing. A bird's wings differ from a knife in that...

Scientists long thought they knew what the wings of early birds looked like. But new reconstructions of Archaeopteryx and its kin suggest quite different feather arrangements on their wings with profound implications for the evolution of flight.

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....