Science: Flight Recorder

The test pilot’s job is still tough and exacting but he now can take along an automatic observer to handle the vitally important paper work. This mechanical secretary is the new electronic flight recorder developed (after nine years’ work at a cost of $250,000) by Philadelphia’s Brown Instrument Co., a division of Minneapolis-Honeywell Regulator Co.

Before the flight recorder was introduced, test temperatures and stresses were jotted down by the pilot from a few relatively inaccurate dashboard instruments. Plane builders thought they were lucky if a pilot managed to get eight or nine readings in five minutes—correct to the nearest 10 or 15 degrees. The automatic observer takes and prints 144 temperature readings of cylinders, propeller bearings, oil in the fuel lines, carburetors, etc. every three or four minutes for as long as eight hours at a stretch. It can also measure normally impossible to get pressure on wing struts, bulkheads, tail surfaces, etc.

About the size of a suitcase, weighing 128 lb., the compact device is already in use for testing all types of planes from single-seater fighters to B-19s. A recorder costs $2,000 (Glenn Martin paid for one in a week with money saved in life-insurance premiums for the three observers usually carried on heavy bomber test flights). But the supply of recorders is still limited.