Bird Aerodynamics

Or: Why herons, cranes and egrets don't fly with their necks extended.

We all know what happens when you "stick your neck out" lol

There is a point where the length of the neck is no longer aerodynamic and the sharply pointed beak is better kept right in front of the body. They would not get any "lift" from their narrow, pointed beaks but, that shape does pierce the air quite nicely. Just like the nose of a jet aircraft.

Ducks and geese fly with their necks outstretched.
The flat bills of ducks and geese aid in acquiring "lift". I'm willing to bet that they can actually rest their "chins" on the wind as they fly. They now design highly efficient aircraft that utilize the canard (fr. duck) profile that features a small wing way out in front.

All flying birds also get lift from the way air flows easily over their straight backs but, pushes their rounder undersides upward as they propel themselves through the air with their wings.

Want more? lol
The pointed, elongated cone shape of the Heron's beak pierces the air and makes a cone shaped vacuum that is widened even further by the shape of the front of the bird. As the air is forced around the bird, frontal drag is reduced. If the neck was extended, this effect would be lost and the vacuum would collapse behind the bird's head, in front of the bird's body, and the air would rush back in, creating even more drag and turbulence than it had to begin with.

The wide, flat bills of ducks and geese create a wedge shaped vacuum as the birds propel themselves through the air. If you have ever noticed, their wings beats have a very short up and down travel distance, staying just on the edge of the vacuum wedge that their bills have created. Even the geese flock formations are based on creating an even larger wedge shaped vacuum for all of them to travel within.

The vacuums that birds create not only reduce drag, they create thrust. That is how the shape of a Peregrine Falcon enables it to exceed the pull of gravity (freefall) without flapping it's wings. In a dive, the Peregrine's form, past it's head, becomes a very long cone shape. The vacuum that it's head creates while moving through the air, collapses behind it's head and the air starts rushing back in around the contoured shape of the bird, from front to back, propelling the bird forward. Same design as fish. If you've ever tried to tighten your grip on the tapered back end of a fish, you know that it shoots forward out of your grasp. And, the tighter you try to squeeze, the faster it goes. Lost a couple of good ones that way. :(

By the way, using a trained Peregrine Falcon, they have now clocked it's dive speed at over 370 kilometers per hour! A man designed a suit to mimic the Peregrine form and started to approach those speeds. He discovered a major problem...slowing down. :(




This message was edited Oct 2, 2009 10:19 PM

:-) Thanks BB!

Thanks for the heads up, Resin. Yes, I did mean kilometers per hour. Either way, it was REALLY fast. :)

Yep, 370 MPH is about 630 KPH.

and 370 KPH is about 230 MPH.

Hack