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MORE THAN ONE TYPE
OF MOTION
As pilots and aviation buffs celebrate National Aviation Day on
August 19th, it is appropriate that we look at the flight of
birds rather than airplanes.
There are four generalized levels of motion
through the air. Parachute, Glide, Flight, and Soaring.
Defined as basically falling through the air
at an angle of greater than 45 degrees, any animal can
Parachute. The term comes in to play when the animal falls in a
controlled manner. When he leaps from a high branch to a lower
one or to the ground, he is, in effect, parachuting.
The second motion is Glide. This is similar
to parachuting except the angle of descent is less than 45
degrees allowing the animal to travel greater distances.
Flight is accomplished by birds flapping
their wings. This is the obvious difference between the flight
activity and parachuting or gliding where no flapping motion is
used. A bird in flight controls his motion, his direction of
travel, and his speed. Parachuting and gliding are governed
primarily by gravity.
Many birds in flight can
Soar. Think of watching an eagle in flight. Although it looks
like they are gliding high in the sky, soaring is actually a
very complex behavior.
Using his wings only to take off or land or
to make slight adjustments while soaring, birds use the
surrounding air currents to soar higher, lower, or to maintain
their altitude.
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