We Just Aren’t Built to Fly
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.
In order to fly:
- 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.