Bewick's swan taking off with approach run

�@Since a swan cannot moves its wing quickly and the load per wing area and the stall velocity are large because the large-size and the long-arm, it makes an approach run by using beating together with kicking. In order to increase the thrust, the swan beats down the full opened wing from backward up to forward down with vigor, and makes maximum the angle of attack of the secondaries, and bends forward the primaries to produce the muximum thrust and prevent the boundary layer separation for flapping down. The spread and bent down tail may make a poor but flap effect. Swan kicks the water to backward by the full opened webfeet with vigor and makes muximum the momentum of the pushing back water. (Prod. Jun. 2003, scale 1/2, No.2)

return
next