A flight simulator is a device that artificially re-creates aircraft flight and the environment in which it flies, for pilot training, design, or other purposes. It includes replicating the equations that govern how aircraft fly, how they react to applications of flight controls, the effects of other aircraft systems, and how the aircraft reacts to external factors such as air density, turbulence, wind shear, cloud, precipitation, etc. Flight simulation is used for a variety of reasons, including flight training (mainly of pilots), the design and development of the aircraft itself, and research into aircraft characteristics and control handling qualities.
The term "flight simulator" may carry slightly different meaning in general language and technical documents. In past regulations, it referred specifically to devices which can closely mimic the behavior of aircraft throughout various procedures and flight conditions. In more recent definitions, this has been named "full flight simulator".. The more generic term "flight simulation training device" (FSTD) is used to refer to different kinds of flight training devices, and that corresponds more closely to meaning of the phrase "flight simulator" in general English.
In 1910, on the initiative of the French commanders Clolus and Laffont and Lieutenant Clavenad, the first ground training aircraft for military aircraft were built. The "Tonneau Antoinette" (Antoinette barrel), created by the Antoinette company, seems to be the precursor of flight simulators.
An area of training was for air gunnery handled by the pilot or a specialist air gunner. Firing at a moving target requires aiming ahead of the target (which involves the so-called lead angle) to allow for the time the bullets require to reach the vicinity of the target. This is sometimes also called "deflection shooting" and requires skill and practice. During World War I, some ground-based simulators were developed to teach this skill to new pilots.