Birds inspired
our first attempts to fly, but our progress was limited until we learned that
we could not fly like them. Thanks to their light weight, great strength, and
complex biological design, birds and other flying creatures can use their wings
to create both lift and thrust, as well as to maintain control.
Drawing, sheet 2
of 5, U.S. Patent No. 398984, issued March, 5, 1889, for Reuben J. Spaulding's
Flying Machine. Consisting of wings and a tail attached to a man, the
man-powered ornithopter device was designed
to make its wearer look (and fly like) a bird.
Credit:
National Air and Space Museum, Smithsonian Institution, Archives Reference No.:
74-741
● We need to overcome our own
weight—that is, the force of gravity.
● To overcome gravity, we
need to create an upward force called lift.
● To create lift, we need to
generate thrust for forward motion.
● To keep moving, we need to
overcome the resistance of the air—a force called drag.
But using only
our muscles, we can’t get off the ground very high or very far for very long.
So instead, we’ve created machines to do what we alone cannot. We separated the
functions of lift and thrust, using wings to produce one and engines to produce
the other.
Though we still
cannot fly like birds, we can now fly with them.