The E6B Flight Computer, or simply the "whiz wheel", is a form of circular slide rule used in aviation. They are mostly used in flight training, but many professional and even airline pilots still carry and use these flight computers. These flight computers are used during flight planning (on the ground before takeoff) to aid in calculating fuel burn, wind correction, time en route, and other items. In the air, the flight computer can be used to calculate ground speed as well. The back is designed for wind correction calculations, i.e., determining how much the wind is affecting one's speed and course.
They are usually made out of cardboard and plastic, or aluminum and plastic, with printed lettering and markings, or engraved into the metal.
The E6-B has been around a long time. It was developed in the United States by Naval Lt. Philip Dalton in the late 1930s. The name comes from its original part number for the U.S Army Air Corps in World War II.
For easy, accurate, and speedy calculation, the flight-simmer should try the virtual E6-B. It is a freeware software program that calculates the wind correction angle, ground speed, weight and balance, fuel consumption, and a host of other things.