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The Link Trainer
*Click on images to enlarge
 In
the late 20’s Edwin A. Link learned to fly while working
for his father in Binghamton, New York who manufactured organs
and pianos. Because
of the economic depression at that time, flying lessons became too
costly. Link got the idea to shorten the expensive flying lessons
by learning
rudimentary piloting skills using a ground aviation trainer. Drawing
from his expertise in air-driven pianos and pipe organs, Link used
organ parts and compressed air to build the first flight simulator.
In 1928, Edwin A. Link left his father's organ building business
to begin work on a "pilot trainer." He designed the trainer
using suction through fabric bellows to cause motion. Organ bellows
and a motor provided the means for the trainer, mounted on a pedestal,
to pitch, roll, dive and climb as the student "flew" it.
In 1931 he received a patent on his "pilot maker" training
device.
 Most
of his first sales were to amusement parks. In the beginning there
was very little interest by the flying community in Link’s
trainer. Initially the trainer was meant for instruction of visual
flight, but in 1934, after a series of tragic accidents while flying
the air mail, the Army Air Corps bought six Link trainers to assist
in training pilots to fly at night and in bad weather, relying on
instruments. The second customer for the Link trainer was the Japanese
Imperial
Navy in 1935. Many Japanese pilots were trained in these Link trainers
and used their skill and knowledge in fighting the American planes
in World War II.
 The
need for pilots with instrument training in World War II resulted,
by the end of the war, in Link delivering 6271
Link trainers to the Army and 1045
to the Navy . The Link trainers were also used
by 35 foreign countries.
Although Army Air Force's aviation cadets
flew various trainer aircraft, virtually all took blind-flying
instruction in the Link.
Movement of the trainer is accomplished
by vacuum operated
bellows, controlled by valves connected to the control wheel (or
stick) and rudder pedals. An instructor sat at the desk and transmitted
radio
messages which the student in the Link heard through his earphones.
Inside the "cockpit", the student relied on his instruments
to "fly" the Link through various maneuvers while his
navigational "course" was
traced on a map on the desk by the three-wheeled "crab".
Slip stream simulators gave the controls the feeling of air passing
over control surfaces, and a rough air generator added additional
realism during the "flight".
The Link Trainer holds a significant place in aviation history.
It was the first true flight simulator, and provided safe training
to hundreds of thousands of student pilots during the 1930s and 40s.
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Restoration Program
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| In 1993,
the Western Museum of Flight (WMOF) initiated the restoration of a
1942 Model C-3 Link Trainer. A crew of WMOF Volunteer Docent/ Restorers
staffed the project. They had at their disposal an inventory of donated
obsolete and nonfunctioning parts of 1940’s era Link Trainers,
that had been accumulated by the museum over several preceding years.
This inventory consisted of: two bases, two octagons, an almost fully
equipped fuselage, two blind flying hoods, an almost complete set of
Link Trainer operation, overhaul, and maintenance technical manuals,
and a sufficient amount of spare bellows, valves, turning motors, telegon
transmitters, and instruments. |
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Salvaged
C-3
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Octagon
and Desk
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Octagons
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Base
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Components
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Aileron
Valve
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Instructor's
Desk
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For the
first phase of the project, the crew tore down the existing components
and meticulously drew up scale drawings that would be used to rebuild
the trainer and its various mechanical, electrical, and pneumatic systems.
All of the major valves, linkages, tubing, bellows, and instruments
were diligently taken apart, cleaned, put together again, and/or fabricated
per the technical orders in the Link maintenance and overhaul manuals.
The highly labor intensive, time consuming, and skilled work would
require two years to accomplish. During this period, the process of
putting together and completely rewiring the Link’s base, central
column, vacuum compressor, and main electric panel were accomplished.
In addition, the Link’s octagon with its master climb/dive and
banking bellows was completely restored and work was initiated on the
restoration of the Instructor’s Desk, its radio and automated
flight tracking device.
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Motor
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Control
Stick
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Valves
and Damper
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Base
and Motor
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| In
March 1997, restoration of the Link’s fuselage was completed.
With the fuselage now sitting on the Link’s octagon, the
restored components were then carefully reinstalled. This included
all the major and minor valves, bellows, metal and rubber tubing, rough
air generator, linkages, springs, telegon transmitters, turning motor,
rudder pedals, control stick, altitude and airspeed vacuum cans, vibration
motors, air dampers, cockpit lights, air circulating fan, and pilot’s
radio. Although most of the restored components were used, some parts
had to be fabricated on the spot. Once again, all this was done per
the technical manual’s specifications, aided by the fine scale
drawings made during the first phase of this project. |
 The
next step was the
restoration and installation of the Link’s instrument panel.
The restored panel now contained a fully functional magnetic compass,
gyro-horizon indicator, altitude meter,
airspeed meter, turn and bank bubble, climb and dive indicator, engine
rpm meter, clock, radio beacon, glide path indicator, fuel gauge, on/off
switch, pitot tube heater switch, and fuel switch.
In July 1997, the time consuming
re-calibration and testing of all of the Link’s major and minor valves,
electrical transmitters, mechanical linkages, vacuum chambers and air dampers
was completed. The partially restored pilot’s seat was then installed
in the cockpit. Now, with one of the crew seated in the cockpit, the Link
was
given its
first full powered systems test per instruction in the Link’s technical
manuals. For all intents and purposes, the Link performed beautifully,
flying level, banking and turning, climbing, diving, and stalling. A sign
was affixed to the fuselage announcing to all who viewed it that
the Link had successfully had its “First (post full restoration)
Flight” on 3 July 1997.
| In
October 1997, California’s Santa
Maria Air Museum donated a usable set
of Link Trainer wooden framed, cloth covered wings, with movable
ailerons, and wooden tail with movable rudder and elevators.
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Restored Wings, Elevator and
Rudder
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Disaster
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In
November 1997, disaster struck the project. Arriving
at the Museum to start work, the team found what they thought
was sawdust on the floor, outlining the Link’s
fuselage and base. Upon close inspection they also found several
small piles of this “sawdust” inside the Link’s
fuselage. |
It was finally deduced
that evidently long dormant termites in the old wooden framework of the
fuselage had awakened and become active again. The entire wooden fuselage
frame and floor were starting to crumble. This required a complete teardown
and removal of all the painstakingly installed Link components. The affected
fuselage was then removed from the octagon and destroyed. Luckily the octagon
had been spared, but, as a safety measure, it was inspected and thoroughly
treated with a termite inhibiting spray.
the Link’s Instructor’s Desk and Blind Flying Hood/Canopies
were inspected
and treated. |
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February 1998, March
Air Force Base Air Museum provided a usable Link Trainer fuselage.
This fuselage was found to be in fairly good shape. It had been
denuded of all of its internal hardware, access doors, seat and backrest,
but would only need a small amount of repair to bring it back into
shape. It was completely inspected for signs of termites. The fuselage
was quickly cleaned up, treated, mounted, and restored.
Once again
all of the required restored hardware, electrical,
mechanical, and pneumatic systems were installed in the fuselage. |
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By
year’s end, 1998, the work was finally completed and the newly
restored second Link fuselage was installed in a jury rigged paint
booth within the WMOF hanger and painted in the 1940’s style
Army Air Corp distinctive blue colored enamel. Once again all the
Link’s systems were re-calibrated and tested and the Link performed
per specifications.
In 1998, the Link’s wings and tail
assemblies were fully restored. The wing’s frames were repaired
as needed and their cloth coverings patched and sealed. The wooden tail
assemblies were cleaned
and sanded. The wing’s ailerons hinges, brackets, and cables,
along with the tail’s rudder and elevator’s hinges, cables,
and brackets, were then restored to full working order. These assemblies
were then painted in the 1940’s style Army Air Corp trainer distinctive
yellow enamel. The restored wings and tail were installed on
the Link’s fuselage. A new fixture had to fabricated to
attach to the restored control stick assembly that would take, secure
and activate the wing’s ailerons, when the stick was moved from
its center position to the right or left. This was machined
from a solid block of aluminum and when fitted, performed its required
function perfectly. Now the Link began
to look like a real little airplane.
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| In
1999,the Link’s Blind Flying Hood/Canopy were completely
restored . All the old, rotted cloth covering had to strip off
and the wooden frame cleaned and strengthened .
It was then recovered with
aircraft linen, hot ironed , primed, and finally repainted in its
1940’s era Army Air Corp trainer blue enamel, with silver
colored false windows.
After installation of the hood, newly acquired 1942 era Army
Air Corp aircraft roundels were affixed to the wings with red and white
strips on the
rudder.
Small
red “NO STEP” and “NO PUSH” caution signs were
painted on the Link’s wings and rudder. |
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Original
Corroded Hood
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Frame
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Recovered
and Primed
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| In
June 1999, the Link’s metal-framed base was then fitted
with pegboard cover panels and painted with a black enamel. A black
cloth skirt was
fashioned and affixed to the fuselage base and anchored to the octagon.
The covering protected the major climb, dive, and bank bellows.
The
Link was now officially completely restored, displayed in all its bright
colors. Visitors to the museum could now see the Link,
as it would have been set up in a typical World War II Army Air Corp
training building.
Its Instructor’s Desk showed its radio, in its partially opened
center drawer, an aerial flight map positioned under its Automatic
Tracker, and its Instructor’s earphones and microphone displayed
on their holder awaiting use by the Instructor. |
In
the late 20’s Edwin A. Link learned to fly while working
for his father in Binghamton, New York who manufactured organs
and pianos. Because
of the economic depression at that time, flying lessons became too
costly. Link got the idea to shorten the expensive flying lessons
by learning
rudimentary piloting skills using a ground aviation trainer. Drawing
from his expertise in air-driven pianos and pipe organs, Link used
organ parts and compressed air to build the first flight simulator. 
Most
of his first sales were to amusement parks. In the beginning there
was very little interest by the flying community in Link’s
trainer. Initially the trainer was meant for instruction of visual
flight, but in 1934, after a series of tragic accidents while flying
the air mail, the Army Air Corps bought six Link trainers to assist
in training pilots to fly at night and in bad weather, relying on
instruments. The second customer for the Link trainer was the Japanese
Imperial
Navy in 1935. Many Japanese pilots were trained in these Link trainers
and used their skill and knowledge in fighting the American planes
in World War II.
The
need for pilots with instrument training in World War II resulted,
by the end of the war, in Link delivering 6271
Link trainers to the Army and 1045
to the Navy . The Link trainers were also used
by 35 foreign countries.
Although Army Air Force's aviation cadets
flew various trainer aircraft, virtually all took blind-flying
instruction in the Link.
