Measurements of the wings of swifts in a wind tunnel reveal the remarkable changes of in-flight performance afforded by changing wing shape. Swifts can halve sink speed or triple turning rate by choosing the most suitable sweep. Extended wings are superior for slow glides and turns. But swept wings are superior for fast glides and turns, they allow the birds to bear the extreme accelerational loads of fast manoeuvres in the air.
- D. Lentink
- U. K. Müller
- J. L. van Leeuwen
