Editing Link Trainer (section)

==Link Trainer models==
Several models of Link Trainers were sold in a period ranging from 1934 through to the late 1950s.  These trainers kept pace with the increased instrumentation and flight dynamics of aircraft of their period, but retained the electrical and pneumatic design fundamentals pioneered in the first Link.

Trainers built from 1934 up to the early 1940s had a color scheme that featured a bright blue fuselage and yellow wings and tail sections. These wings and tail sections had control surfaces that actually moved in response to the pilot's movement of the rudder and stick. However, many trainers built during mid to late World War II did not have these wings and tail sections due to material shortages and critical manufacturing times.

===Pilot Maker===
The Pilot Maker was Link's first model. It was an evolution of his 1929 prototype and was used in Mr. Link's Link Flying School and later by other flying schools. During the Depression years versions of the Pilot Maker were also sold to amusement parks. In fact, his patent (US1825462 A) for the Pilot Maker was titled ''Combination Training Device for Student Aviators and Entertainment Apparatus''.<ref name="Sky to Sea" />

===AN-T-18===
The most prolific version of the Link Trainer was the AN-T-18 (Army Navy Trainer model 18), which was a slightly enhanced version of Link's ''C3'' model.  This model was also produced in Canada for both the [[Royal Canadian Air Force]] and the [[Royal Air Force]] with a somewhat modified instrument panel, where its model designation was ''D2''.<ref name="RAeSPaper">{{cite web |last1=Jaspers |first1=Henrik |title=RESTORING AND OPERATING HISTORICAL AVIATION TRAINERS |url=http://home.wanadoo.nl/hjaspers000/FlightSimulation.PDF |website=Wanadoo |access-date=28 January 2019 |archive-url=https://web.archive.org/web/20041209171227/http://home.wanadoo.nl/hjaspers000/FlightSimulation.PDF |archive-date=9 December 2004 |date=27 May 2004 |url-status=dead }}</ref> It was used by many countries for pilot training before and during the Second World War, especially in the [[British Commonwealth Air Training Plan]].

The AN-T-18 featured rotation through all three axes, effectively simulated all flight instruments, and modeled common conditions such as pre-[[Stall (flight)|stall]] buffet, overspeed of the retractable [[Landing gear|undercarriage]], and [[Spin (flight)|spin]]ning.  It was fitted with a removable opaque canopy, which could be used to simulate blind flying, and was particularly useful for instrument and navigation training.

====AN-T-18 design and construction====
[[File:Link Trainer Shuttleworth Collection Controls.jpg|thumb|right|The instrument panel of the Link Trainer at the [[Shuttleworth Collection]] in the UK]]
The AN-T-18 consists of two main components:

The first major component is the trainer, which consists of a wooden box approximating the shape of a fuselage and cockpit, connected via a [[universal joint]] to a base.<ref>Kelly 1970, pp. 70–71.</ref> Inside the cockpit is a single pilot's seat, primary and secondary aircraft controls, and a full suite of flight instruments. The base contains several complicated sets of air-driven bellows to create movement, a vacuum pump that both drives the [[bellows]] and provides input to a number of aircraft instruments, a device known as a Telegon oscillator that supplies an 85 VAC 800 Hz sinusoidal reference signal to the remaining pilot and instructor instruments, and a wind drift analog computer.

The second major component is an external instructor's desk, which consists of a large map table; a duplicate display of the pilot's main flight instruments; and the Automatic Recorder, a motorized ink marker also known as "the crab". The crab is driven by the Wind Drift computer and moves across the glass surface of the map table, plotting the pilot's track. The desk includes circuits for the pilot and instructor to communicate with each other via headphones and microphones, and controls for the instructor to alter wind direction and speed.<ref>Kelly 1970, pp. 65–68.</ref>

The AN-T-18 has three main sets of bellows. One set of four bellows (fore and aft and both sides of the cockpit) controls movement about the pitch and roll axes. A very complicated set of bellows at the front of the fuselage controls movement about the [[Yaw angle|yaw]] axis. This Turning Motor is a complex set of 10 bellows, two crank shafts and various gears and pulleys derived from early player piano motors.  The Turning Motor can rotate the entire fuselage through 360-degree circles at variable rates of speed.  A set of electrical [[slip ring]] contacts in the lower base compartment supplies electrical continuity between the fixed base and the movable fuselage.

The third set of bellows simulates vibration, such as stall buffet.<ref>Kelly 1970, pp. 65–66.</ref> Both the trainer and the instructor's station are powered from standard 110VAC/240VAC power outlets via a [[transformer]], with the bulk of internal wiring being low voltage. Simulator [[logic]] is all analog and is based around [[vacuum tube]]s.