Florida Automatic Computer
FLAC I & FLAC II
1950-1960
Florida Automatic Computer FLAC I Florida Automatic Computer
FLAC I
1950-1956




FLAC - Florida Automatic Computer - Patrick AFB, Florida

In December 1950, a group of Air Force Civilian engineers, at the Atlantic Missile Range, PAFB, Florida, was given the task of designing and constructing FLAC. Three FLACs were built specifically to process missile test data. The first FLAC was placed in operation in April 1953. The second and third in the fall of 1956. They were operated by RCA, subcontractor to Pan American Airways.

FLAC computers supported flight tests of the early ballistic missiles and air breathing cruise missiles. The V2, Redstone, Juno, Snark, Matador, Bomarc, Navaho, Atlas, Thor, and RTV, all were supported by FLAC computers.

FLAC was also used in survey calculations for latitude, longitude and altitude of the locations of launch pads, tracking cameras and RADARs. In one survey FLAC was used to process ballistic camera data collected during a special Redstone missile flight. FLAC computations improved the known position of survey markers on the Island of Bermuda by ninety feet.

FLAC was a three address machine and one of the first to have both an automatic program location counter and an index register. FLAC was modeled after the South Eastern Automatic Computer, SEAC, used by the US Bureau of Standards. It embodied the von Newmann computer architecture. FLAC I had 512 words of acoustic delay line memory. Arithmetic calculations were fixed point operations. The later FLAC model, FLAC II, was more advanced and had 4096 words of magnetic core memory.

Missile tests produced large amounts of optical and electronic tracking data. These data were recorded on rolls of seven hole flexowriter punched paper tape, cartridges of magnetic wire and reels of magnetic tape for input to FLAC. Subsequent data processing produced missile test reports for the Missile Contractors and the Department of Defense.

Computer Programs, required to transform the tracking data into missile trajectory and performance data were written in machine language. There was no high level language, no assembler or compiler for the FLAC programmers to use. The number base or radix was 16. There were only 16 symbols available in FLAC machine language: the numbers 0 through 9 and the letters A through F.

A library of scientific mathematical programs was developed for FLAC. This library was maintained on wire recorders. Programs were loaded from the wire recorder into FLAC memory for execution.

FLAC I Wire Recorder All programs, including the elementary functions such as Sine, Cosine, Tangent, Roots, Matrix Algebra and Cordinate Transformations; photogrametric calculations, refraction correction and smoothing were written from scratch by FLAC programmers. The library included computer programs for both optical and electronic missile tracking instruments. Programs were written for decoding syncoptic coded RADAR data, such as the Gianinni Code and Gray Code. Programs were written for double precision calculations.

Photo by John Cundiff

FLAC was used to process missile flight test data from a variety of tracking instruments. These tracking devices were both optical and electronic. Specifically, RADARs, theodolites, fixed cameras and ballistic cameras were employed on the Atlantic Missile Range to track the early missiles in flight.

The data collected from missile tests was processed by the FLAC computers beginning in 1953 and extending into 1960 when they were replaced by IBM 709 scientific computers.