Now you know that flying machines need thrust and lift to get off the ground. Lacking engines, gliders must make up for their lack of thrust by maximizing lift. They have skinny bodies and sprawling wings constructed of ultralight materials. These massive wings provide more lift with less air moving over them than conventional plane wings. Glider pilots seek out “thermals,” columns of heated air that rise up from the ground. Thermals are invisible, but they typically form over dark patches of terrain – parking lots or dirt fields. The pilots circle inside the column, letting the heated air push them higher and higher, until they reach the desired altitude. Then they leave the column and glide slowly back to the ground. Glider pilots can also simulate thrust by flying into strong winds.
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