The Link Aeronautical Trainer
A Link Aeronautical Trainer of the late 1930s
The Link Trainer is one of the most recognizable icons of early aviation flight training. During the Second World War thousands of young men learned the fundamentals of flying in one of these machines. Forerunner to the present day flight simulator, the Link Trainer was the brainchild of Edwin Albert Link, who patented his cockpit-like wooden contraption in 1929. Thanks to the work of this one time piano and organ builder flight training become much safer.
Ed Link's odyssey in becoming the "Father of Flight Simulation" began in 1927
when, at the age of 23, he began working for his father at the Link Piano and Organ
Factory in Binghamton, NY. Ed Link built pianos and tuned organs, a job that
required a thorough knowledge of the pumps, valves and bellows that directed the air power
within the instrument.
It was during this period that Link, whose passion was aviation, began to wonder if he
could create a training device that could give pilots the skills they would need to safely
fly.
Ed Link's idea to develop a ground-based flight trainer was given a boost during a chance
meeting with a group of fliers at Wright Field, OH in 1927. In a book on his life,
"From Sky to Sea," Ed Link said that he watched as a "Major Ocker"
tried to help a group of aviators at Wright Field understand the problems with direction
that are encountered while in flight.
"He'd blindfold the people and twist them around in this seat a few times, then ask
them which way they were turning," Ed Link states in the book." They
invariably said the wrong way and that was one of the things that gave me the idea that
you could make a whole airplane to train a pilot to do everything. He (Major Ocker)
was merely demonstrating... that you couldn't tell where you were going by sight or feel.
You had to have an instrument that told you where you were turning and whether you
were flying straight or level."
In that same year, 1927, Link learned to fly himself. It was during this time that
he also learned about a French training technique called the "Penguin System"
that had been used during the First World War to train many American pilots. In this
system, the novice pilot would taxi a plane on the runway, gaining some limited feel for
the controls. Link wondered if it was possible to build a training system that would
simulate the feel of an aircraft's controls. Over the next 18 months, he worked in
his father's piano and organ factory's basement to create a machine that could mimic the
experiences of flying an airplane without ever leaving the ground. Link applied the
principles he had mastered in building fine organs to the design of his new flight
training device. He called his invention the "Pilot Maker."
Early Link Trainer and Course Plotter on Instructor's Desk
The Pilot Maker featured a stubby wooden cockpit/fuselage mockup (complete with stubby
wooden wings on the sides) mounted on organ bellows that Link had borrowed from his
father's piano factory. An electrically driven suction pump mounted in the fixed
base fed the various control valves operated by the stick and rudder, while another motor
driven device produced a repeated sequence of attitude disturbances, all of which allowed
the trainer to bank, climb and dive as a pilot operated the controls in the cockpit.
In common with other trainers of the time, the performance was adjusted by trial and error
by the designer until the correct "feel" was obtained.
The first description of the trainer made no reference to instruments and the
device was therefore primarily intended to demonstrate the effects and operations of the
controls of the simulated aeroplane. As with other synthetic devices of this time, the
simulated effects of the ailerons, elevators and rudder were independent and they did not
represent a true reproduction of an aircraft's co-ordinated behaviour.
Edwin Link with Amelia Earhart
Ed Link received a patent [US#1.825.462] for his new pilot trainer, described as "an
efficient aeronautical training aid - a novel, profitable amusement device," on April
14, 1929, the first in a long series of patents that he would receive for continued flight
simulation innovations. After unsuccessfully trying to sell his idea to companies,
Edwin set out on a tour around America selling rides in his machine for 25 cents. He
also sold his device to amusement parks and even a few commercial flight operations.
Still, the Pilot Maker failed to prove a success. Then in 1930, the Pioneer
Instrument Company of Brooklyn, New York installed a turn and bank indicator, a magnetic
compass, and an airspeed indicator in one of the Pilot Makers. They hoped to show
the need for these instruments in order to prevent vertigo. Their idea proved successful
and caught the attention of the U.S. Navy which purchased the third trainer in which
instruments were installed.
By adding a hood that enclosed the pilot in the simulator and an
instrument panel, the function of the trainer had been expanded from pre-flight to
instrument flight training. Eventually his device came to the attention of the U.S.
Army Air Corps which also saw the potential for such a training device, but at the time
budgetary constraints prevented their taking the matter further. A national crisis
soon helped to overcome this concern.
USAAC Cadet training in a Link Trainer
In February 1934, the U.S. Army Air Corps was ordered to fly the airmail in the United
States following a dispute between the Federal government and the airmail contractors.
It quickly became apparent that Army pilots lacked experience in flying
"blind" at night or in inclement weather. Five pilots were killed in the
first few days of flying the mail. The Army quickly began a search for solutions and
arranged for Link to visit the Newark Airport in New Jersey to demonstrate his trainer.
On the day of the demonstration the weather turned stormy, but Link, himself an
instrument-trained pilot was able to fly in safely which succeeded in convincing the Army
that instrument flight was practical and could be taught in his trainer. He won his
contract, and the first significant military sale of what now had become known as the Link
Aeronautical Trainer took place. The Air Corps purchased six of the machines.
Typical Link Trainer used during World War II
Although acceptance was slow at first, eventually the Air Corps was using the devices
across the nation in its training facilities. Successive models of the Link Trainer
were able to rotate through 360 degrees which allowed a magnetic compass to be installed,
while the various instruments were operated either mechanically or pneumatically.
Altitude, for example, was represented by the pressure of air in a tank directly connected
to an altimeter. Rudder/aileron interaction was provided in the more advanced
trainers, as was a stall feature. The reproduction of aircraft behaviour and
dynamics was still produced in an empirical manner. A further increase in the
usefulness of the trainers was achieved with the attachment of a course plotter. This
consisted of tortoise like device, on three wheels,which was self-propelled and steerable;
the course of the simulated flight was traced on a chart by means of an inked wheel.
By relating the position of the student's aircraft to marks on the chart, the
instructor was able to manually control the transmission of simulated radio beacon signals
to the trainer.
The Link Model 45 was a fully integrated trainer where the movements and instruments worked together; if the pilot pulled back on the control stick, the altitude indicator would show that the plane was climbing as the speed indicator showed that the plane was decelerating. The fuel gauge would eventually go to empty, and the engine noise would become erratic if the engine temperature rose.
Throughout the 1930's the Link Trainer was produced in various versions and was sold to many countries, including Japan, the Soviet Union, France and Germany. With the rumblings of war, trainers began to appear in such places as England, France and other nations that would one day be combatants.
The first Link Trainer to be sold to a commercial operator was delivered to American Airlines in 1937.
Today the flight simulator business is a multi-million dollar industry with simulators training pilots throughout the world. Link simulators are providing training for pilots and aircrews on some of the world's most advanced military aircraft including the B-2, F-117, F/A-22, F/A-18, F-16, C-130, T-45 and a wide range of attack, reconnaissance and transport helicopters. Link simulators are licensed and manufactured by L-3 Communications.
Edwin Link left the aviation industry in the 1950's to pursue a career in oceanography. He died in 1981.
A Link Trainer on display at the MAPS museum near Akron, Ohio
