1210 Massillon Road
Akron 15, Ohio

  The Goodyear Tire and Rubber Company formed a division in the 1920s called the Goodyear Zeppelin Company. In the 1930s the Goodyear Zeppelin Company built the great airships Akron and Macon. And as the Goodyear Aircraft Company, built F4U Corsairs, and blimps during WWII. About 1948 the Goodyear Aircraft Corporation began moving into missle development and needed analog simulation equipment to aid in missle design. With the GEDA (Goodyear Electronic Differential Analyzer) line of analog computers, the Goodyear Aircraft Corporation was an early force in the development of the electronic analog computer.
  Today, the company is Lockheed Martin Naval Electronics & Surveillance Systems-Akron.

  Each model had three major units. The L or linear unit contained the amplifiers, plugboard and controls that were needed for all problems. The N or nonlinear unit contained components to generate nonlinear curves, do multiplication or division of voltages. The R or recorder unit was a multichannel recorder that recorded 6 transient waveforms on chart paper, providing the output information.
  The first model was the L1/N1/R1.

The GEDA commutator stabilization system

GEDA commutator stabilizers
  On the left is the stabilizer for the L-3,
on the right, the stabilizer for the A-14.
The A-14 stabilizer can balance up to 85
amplifiers at 3cps.

  The amplifiers in the Model L-1 and L-2 needed to be balanced by hand. On large programs, using a hundred or more amplifiers, the first one balanced often drifted out of range before the last one was balanced, forcing the process to be done over and over before making a successful run.
  The GEDA commutator stabilization system was developed to automatically balance all of the amplifiers by using a motor driven commutator switch which sampled the input grid of each amplifier in turn. The sample offset signal was amplified by the amplifier contained in the stabilizer and fed through a second ganged section of the commutator into a low-pass filter on the balance grid of the amplifier being balanced. The commutator was driven at 3 cps.

No Picture Yet
GEDA L-1/N-1/R-1
Goodyear Aircraft Corp.
Akron 15, Ohio

Introduced in 1949.

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Model L-2
  Model L-2 unit.

GEDA L-2/N-2/R-2
Goodyear Aircraft Corp.
Akron 15, Ohio

  Introduced in 1951. Very similiar to the L-1, but had more stable amplifiers.
  The amplifiers are patched inside the rear of the cabinet.
Operating range: +/- 100 volts DC
Computing Elements: 20 - amplifiers

L-2 computers   A picture of a GEDA center showing (from the left) an R-2 unit, two L-2 units, (maybe) an N-2 unit behind the woman, (maybe) two L-1 units and another recording unit between the women.

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Model L-3
  Model L-3 unit.

GEDA L-3/N-3/R-3
Goodyear Aircraft Corp.
Akron 15, Ohio

  Introduced in 1953. Unlike the L-1 and L-2, the L-3 had self-balancing DC amplifiers. Each amplifier output was sampled a few times a second by a mechanical comutator that fed a voltage back to its input to correct any unbalance.
Operating range: +/- 100 volts DC
Computing Elements: 24 - amplifiers
  18 - pots
  3 - bidirectional limiters
  10 - thermionic diodes (6AL5's)

L-3 computer Frankford Arsenal in 1953
  Model R-3 unit and two L-3 units.

  This unit was installed at Frankford Arsenal in 1953. It had two L-3 units for a total of 48 amplifiers, plus an N-3 multiplier unit and a recorder. It was used to simulate the interior and exterior ballistics of guns, so that powder charges, projectile weights, etc could be varied and the effect on gun range, velocity, etc. could be calculated. It was also used to simulate the computers used for directing guns, simplifying their design.

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Model A-14
Goodyear Aircraft Corp.
Akron 15, Ohio

  A special feature of this computer is an automatic output scanner system which reads out the voltage in every computing element. Options include a digital voltmeter which is used with a precision null-balance bridge for setting pots, and an automatic printer.

Computing Center at Goodyear, Akron   The Computing Center at Goodyear Akron - date unknown

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