![Activities at Royal Naval Air Station Lee-on-solent, 13 To 17 September 1943 A19290](https://upload.wikimedia.org/wikipedia/commons/7/76/Activities_at_Royal_Naval_Air_Station_Lee-on-solent%2C_13_To_17_September_1943_A19290.jpg)
The term Link Trainer, also known as the "Blue box" and "Pilot Trainer" is commonly used to refer to a series of
flight simulator
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 rea ...
s produced between the early 1930s and early 1950s by
Link Aviation Devices, founded and headed by
Ed Link
Edwin Albert Link (July 26, 1904 – September 7, 1981) was an American inventor, entrepreneur and pioneer in aviation, underwater archaeology, and submersibles. He invented the flight simulator, which was called the "Blue Box" or "Link Trai ...
, based on technology he pioneered in 1929 at his family's business in
Binghamton, New York
Binghamton () is a city in the U.S. state of New York, and serves as the county seat of Broome County. Surrounded by rolling hills, it lies in the state's Southern Tier region near the Pennsylvania border, in a bowl-shaped valley at the conflue ...
. During
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, they were used as a key pilot training aid by almost every combatant nation.
The original Link Trainer was created in 1929 out of the need for a safe way to teach new pilots how to fly by
instruments
Instrument may refer to:
Science and technology
* Flight instruments, the devices used to measure the speed, altitude, and pertinent flight angles of various kinds of aircraft
* Laboratory equipment, the measuring tools used in a scientific lab ...
. Ed Link used his knowledge of
pump
A pump is a device that moves fluids (liquids or gases), or sometimes slurries, by mechanical action, typically converted from electrical energy into hydraulic energy. Pumps can be classified into three major groups according to the method they u ...
s,
valve
A valve is a device or natural object that regulates, directs or controls the flow of a fluid (gases, liquids, fluidized solids, or slurries) by opening, closing, or partially obstructing various passageways. Valves are technically fittings ...
s and
bellows
A bellows or pair of bellows is a device constructed to furnish a strong blast of air. The simplest type consists of a flexible bag comprising a pair of rigid boards with handles joined by flexible leather sides enclosing an approximately airtigh ...
gained at his father's
Link Piano and Organ Company to create a flight simulator that responded to the pilot's controls and gave an accurate reading on the included instruments. More than 500,000 US pilots were trained on Link simulators,
as were pilots of nations as diverse as Australia, Canada,
Germany
Germany,, officially the Federal Republic of Germany, is a country in Central Europe. It is the second most populous country in Europe after Russia, and the most populous member state of the European Union. Germany is situated betwe ...
, New Zealand, United Kingdom, Israel, Japan,
Pakistan
Pakistan ( ur, ), officially the Islamic Republic of Pakistan ( ur, , label=none), is a country in South Asia. It is the world's List of countries and dependencies by population, fifth-most populous country, with a population of almost 24 ...
, and the
USSR
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
. Following WWII, Air Marshall
Robert Leckie (wartime RAF Chief of Staff) said "The Luftwaffe met its Waterloo on all the training fields of the free world where there was a battery of Link Trainers".
The Link Flight Trainer has been designated as a
''Historic Mechanical Engineering Landmark'' by the
American Society of Mechanical Engineers
The American Society of Mechanical Engineers (ASME) is an American professional association that, in its own words, "promotes the art, science, and practice of multidisciplinary engineering and allied sciences around the globe" via "continuing ...
.
The Link Company, now the Link Simulation & Training division of
L3Harris Technologies
L3Harris Technologies (L3Harris) is an American technology company, defense contractor, and information technology services provider that produces C6ISR systems and products, wireless equipment, tactical radios, avionics and electronic systems, ...
, continues to make aerospace simulators.
["Link Company."](_blank)
''link.com''. Retrieved: 20 February 2010.
History
Origins
Edwin Link
Edwin Albert Link (July 26, 1904 – September 7, 1981) was an American inventor, entrepreneur and pioneer in aviation, underwater archaeology, and submersibles. He invented the flight simulator, which was called the "Blue Box" or "Link Trai ...
had developed a passion for flying in his boyhood years, but was not able to afford the high cost of flying lessons. So, upon leaving school in 1927, he started developing a simulator. The project took him 18 months. His first pilot trainer, which debuted in 1929, resembled an overgrown toy airplane from the outside, with short wooden wings and fuselage mounted on a universal joint. Organ bellows from the Link organ factory, the business his family owned and operated in Binghamton, New York, driven by an electric pump, made the trainer pitch and roll as the pilot worked the controls.
Link's first military sales came as a result of the
Air Mail scandal
The Air Mail scandal, also known as the Air Mail fiasco, is the name that the American press gave to the political scandal resulting from a 1934 congressional investigation of the awarding of contracts to certain airlines to carry airmail and t ...
, when the
Army Air Corps Army Air Corps may refer to the following army aviation corps:
* Army Air Corps (United Kingdom), the army aviation element of the British Army
* Philippine Army Air Corps (1935–1941)
* United States Army Air Corps (1926–1942), or its p ...
took over carriage of
U.S. Air Mail
United States airmail was a service class of the United States Post Office Department (USPOD) and its successor United States Postal Service (USPS) delivering air mail by aircraft flown within the United States and its possessions and territor ...
. Twelve pilots were killed in a 78-day period due to their unfamiliarity with
Instrument Flying Conditions. The large scale loss of life prompted the Air Corps to look at a number of solutions, including Link's pilot trainer. The Air Corps was given a stark demonstration of the potential of instrument training when, in 1934, Link flew in to a meeting in conditions of fog that the Air Corps evaluation team regarded as unflyable.
As a result, the Air Corps ordered the first six pilot trainers on 23 June 1934 for $3,500 each. In 1936, the more advanced Model C was introduced.
American Airlines became the first commercial airline to purchase a Link trainer in 1937. Prior to World War II, Link trainers were also sold to the U.S. Navy, Civil Aeronautics Administration, Germany, Japan, England, Russia, France, and Canada.
World War II
![LinkTrainerSeymourIndiana](https://upload.wikimedia.org/wikipedia/commons/e/ec/LinkTrainerSeymourIndiana.jpg)
Link and his company had struggled through the Depression years, but after gaining Air Corps interest the business expanded rapidly and during World War II, the AN-T-18 Basic Instrument Trainer, known to tens of thousands of fledgling pilots as the "Blue Box" (although it was painted in different colors in other countries), was standard equipment at every air training school in the United States and Allied nations. During the war years, Link produced over 10,000 Blue Boxes, turning one out every 45 minutes.
During World War II, Link trainers were sometimes run by women.
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''.
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
The Royal Canadian Air Force (RCAF; french: Aviation royale canadienne, ARC) is the air and space force of Canada. Its role is to "provide the Canadian Forces with relevant, responsive and effective airpower". The RCAF is one of three environm ...
and the
Royal Air Force
The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) and ...
with a somewhat modified instrument panel, where its model designation was ''D2''.
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 British Commonwealth Air Training Plan (BCATP), or Empire Air Training Scheme (EATS) often referred to as simply "The Plan", was a massive, joint military aircrew training program created by the United Kingdom, Canada, Australia and New Zea ...
.
The AN-T-18 featured rotation through all three axes, effectively simulated all flight instruments, and modeled common conditions such as pre-
stall buffet, overspeed of the retractable
undercarriage
Undercarriage is the part of a moving vehicle that is underneath the main body of the vehicle. The term originally applied to this part of a horse-drawn carriage, and usage has since broadened to include:
*The landing gear of an aircraft.
*The ch ...
, and
spin
Spin or spinning most often refers to:
* Spinning (textiles), the creation of yarn or thread by twisting fibers together, traditionally by hand spinning
* Spin, the rotation of an object around a central axis
* Spin (propaganda), an intentionally b ...
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
![Link Trainer Shuttleworth Collection Controls](https://upload.wikimedia.org/wikipedia/commons/9/9f/Link_Trainer_Shuttleworth_Collection_Controls.jpg)
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
A universal joint (also called a universal coupling or U-joint) is a joint or coupling connecting rigid shafts whose axes are inclined to each other. It is commonly used in shafts that transmit rotary motion. It consists of a pair of hinges lo ...
to a base. 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
A bellows or pair of bellows is a device constructed to furnish a strong blast of air. The simplest type consists of a flexible bag comprising a pair of rigid boards with handles joined by flexible leather sides enclosing an approximately airtigh ...
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.
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 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
A slip ring is an electromechanical device that allows the transmission of power and electrical signals from a stationary to a rotating structure. A slip ring can be used in any electromechanical system that requires rotation while transmitting p ...
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. Both the trainer and the instructor's station are powered from standard 110VAC/240VAC power outlets via a
transformer
A transformer is a passive component that transfers electrical energy from one electrical circuit to another circuit, or multiple circuits. A varying current in any coil of the transformer produces a varying magnetic flux in the transformer' ...
, with the bulk of internal wiring being low voltage. Simulator
logic
Logic is the study of correct reasoning. It includes both formal and informal logic. Formal logic is the science of deductively valid inferences or of logical truths. It is a formal science investigating how conclusions follow from premises ...
is all analog and is based around
vacuum tube
A vacuum tube, electron tube, valve (British usage), or tube (North America), is a device that controls electric current flow in a high vacuum between electrodes to which an electric voltage, potential difference has been applied.
The type kn ...
s.
Variants
;Pilot Maker
:First production model. Development of 1929 prototype.
"Blue Box"
;A
:Procedural trainer that included only basic instruments.
;C
:Known as the C-2 by the United States Army Air Forces.
Added 10 advanced instruments, radio communication with an instructor, cockpit lights, and automatic course recording.
;C-2
:Commercial version not used by the military.
;C-3
:Used by the United States Army Air Forces.
Includes automatic wind drift device and radio simulator.
;C-5
:Used by the United States Army Air Forces.
Includes automatic wind drift device and actual radio equipment.
;C-8
:Developed in 1945 from the
North American T-6 Texan
The North American Aviation T-6 Texan is an American single-engined advanced trainer aircraft used to train pilots of the United States Army Air Forces (USAAF), United States Navy, Royal Air Force, Royal Canadian Air Force and other air forces ...
with more instrumentation than previous versions. Known as the 1-CA-1 by the U.S. Navy and the Model F.
;D
:Export version.
;D-1
:Used by the British military.
;D-2
:Used by the British military.
Manufactured in Canada.
;D4
:Used by the British military. Built under license in England by Air Trainers Ltd of Aylesbury.
;E
:Commercial version not used by the military.
;E Sp.
:Slight modification for Army and Navy use. Known as the C-4 by the United States Army Air Forces.
;E-1
:Used by the United States Army Air Forces.
;E-2
:Used by the United States Army Air Forces.
;AN-2550-1
:Developed from the C-3, it added landing gear, propeller pitch and flap controls.
Also known as the AN-T-18.
Postwar
;D4 Mk II
:Modification of the D4 to represent the
BAC Jet Provost
The BAC Jet Provost is a British jet trainer aircraft that was in use with the Royal Air Force (RAF) from 1955 to 1993. It was originally developed by Hunting Percival from the earlier piston engine-powered Percival Provost basic trainer, and ...
.
;Model 45
:Advanced version with instruments similar to T-6.
Surviving trainers
, many Link Trainers survive and are exhibited.
See also
*
Aviation safety
Aviation safety is the study and practice of managing risks in aviation. This includes preventing aviation accidents and incidents through research, educating air travel personnel, passengers and the general public, as well as the design of airc ...
*
Bárány chair
The Barany chair or Bárány chair is a device used for aerospace physiology training, particularly for student pilots.
Test
The subject is placed in the chair, blindfolded, then spun about the vertical axis while keeping their head upright or t ...
*
Flight simulator
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 rea ...
*
List of Historic Mechanical Engineering Landmarks
*
Greater Binghamton Airport
Greater Binghamton Airport is a county-owned American airport eight miles north of Binghamton, in Broome County, New York. It is in East Maine, New York and serves the Southern Tier of New York.
The airport was named Broome County Airport t ...
Edwin A. Link Field
References
Notes
Bibliography
* as told to Robert B. Parke
*
Further reading
*
*
*
*
*
External links
The Link Company (now part of L-3 Harris)Link Trainer History
{{ADF aircraft designations
20th-century aviation
Flight training
Military equipment introduced in the 1930s