A flight simulator is a system that tries to copy, or simulate, the experience of flying an aircraft. It is as realistic as possible. The different types of flight simulator range from video games up to full-size cockpit replicas mounted on hydraulic (or electromechanical) actuators, controlled by state of the art computer technology.
Flight simulators are extensively used by the aviation industry for design and development and for the training of pilots and other flight deck crew in both civil and military aircraft.
Engineering flight simulators are also used by aerospace manufacturers for such tasks as:
e Sanders Teacher was a complete aircraft mounted on a universal joint and facing into the wind, able to rotate and tilt freely. Another early flight simulator of about 1910 was built using a section of a barrel mounted on a hoop.
A number of electro-mechanical devices were tried during World War I and thereafter. The best-known was the Link Trainer, produced by Edwin Link in the USA and available from 1929. This had a pneumatic motion platform driven by bellows giving pitch, roll and yaw, on which a replica generic cockpit was mounted. It was designed for the teaching of Instrument (cloud) flying in a less hazardous and less expensive environment than the aircraft. After a period where not much interest was shown by professional aviation, the US Army Air Force purchased four Link Trainers in 1934 after a series of fatal accidents in instrument flight. The world flight simulation industry was born. Some 10,000 Link Trainers were used in the 1939-45 war to train new pilots of allied nations. They were still in use in several Air Forces into the 1960s and early 1970s.
The Celestial Navigation Trainer of 1941 was a massive structure 13.7 m (45 ft) high and capable of accommodating an entire bomber crew learning how to fly night missions. In the 1940s, analog computers were used to solve the equations of flight, resulting in the first electronic simulators.
In 1948, Curtiss-Wright delivered a trainer for the Stratocruiser to Pan American, the first complete simulator owned by an airline. Although there was no motion modelling or visual display, the entire cockpit and instruments worked, and crews found it very effective. Full motion systems came in starting in the late 1950s.
The early visual systems used an actual small model of the terrain. A camera was "flown" over the model terrain and the picture displayed to the pilot. The camera responded to pilot control actions and the display changed in response. Naturally only limited areas of the ground were able to be simulated in this manner, usually just the area around an airport or, in military simulators, typical terrain and sometimes targets. The use of digital computers for flight simulation began in the 1960s.
In 1954, General Precision Inc., later part of Singer Corporation, developed a motion simulator which housed a cockpit within a metal framework. It provided 3 degrees (angle) of pitch, roll, and yaw, but by 1964 improved, compact versions increased this to 10 degrees angle. By 1969 airline simulators were developed where hydraulic actuators controlled each axis of motion, and simulators began to be built with six degrees of freedom (roll, pitch, yaw for angular motion and surge, heave and sway for longitudinal, vertical and lateral translation). Starting in 1977, airline simulators began adopting the modern "cab" configuration where computers are placed in the cockpit area (rather than in off-simulator racks), and equipment is accessed via a wraparound catwalk when the simulator motion system is inoperative.
Around this time great strides were also made in display technology. In 1972 Singer developed a collimating lens apparatus, using a curved mirror and beamsplitter, which projected Out of The cockpit Window (OTW) views to the pilot at a distant focus. These collimated monitors greatly improved the realism of flight simulation. However, each monitor only offered a field of view of 28 degrees and several were needed for a realistic field of view. In 1976 wider angle collimated monitors (e.g. http://www.rickleephoto.com/mosaicfresnel.htm) were introduced, co-called 'WAC windows' standing for 'Wide Angle Collimated'. Finally, in 1982 the Rediffusion company of Crawley, UK, introduced the Wide-angle Infinity Display Equipment (WIDE) that used a curved mirror of large horizontal extent to allow distant-focus (collimated) viewing by side-by-side pilots in a seamless display. For details, see the entry under 'Collimation@. WIDE-type displays are now universal in the highest levels of Full Flight Simulators for aircraft where two pilots are seated side-by-side.
