Unpowered flight is the ability to stay airborne for a period of time without using any power source. There are several types of unpowered flight. Some have been exploited by nature, others by man, and some by both.
Unpowered aircraft are aerial vehicles that can fly without any propulsion mechanism.
The ability to fly short or long distances without power has evolved many times in nature. Many creatures capable of sustained wing-powered flight also soar unpowered for much of the time they are airborne.
Famous quotes containing the word flight:
“Fear of error which everything recalls to me at every moment of the flight of my ideas, this mania for control, makes men prefer reasons imagination to the imagination of the senses. And yet it is always the imagination alone which is at work.”
—Louis Aragon (18971982)