The Airplane - Jay Spenser [82]
The senior Sperry assigned his son, Elmer junior, to the project in a wholehearted commitment that saw the latter actually join Doolittle’s team at Mitchel Field. Father and son had a special reason for supporting this effort so fully. Another of Elmer’s sons—dashing Lawrence Sperry, a pioneer flier and prolific inventor who built the world’s first aviation autopilot in 1914—had been working along similar lines when he disappeared over the English Channel on December 23, 1923.
His Sperry Messenger, a small biplane of Lawrence’s own design, was found soon after floating in the water, its cockpit empty. Closure finally came for the grief-stricken family on January 11 when his body too was recovered.
Lawrence Sperry had taken off in fog.
During World War I, Allied aviators were issued wristwatches. A valuable piece of equipment, the wristwatch allowed time checks even when one’s hands were busy on the controls. Previously regarded as inferior to the pocket watch and an item generally of women’s apparel, the strap-on timepiece’s popularity with returning veterans brought it into mainstream use by all.
In the latter 1920s, a shy young German American living in New York City went looking for local wristwatch makers whose skills could help him build a new aircraft instrument he had conceived. It was an altimeter at least ten times as accurate as the World War I–era altimeters then in use.
Born in Freudenstadt in 1900, Paul Kollsman trained as a civil engineer in Stuttgart and Munich before immigrating to the United States. Arriving in New York at age twenty-three, he worked as a truck driver’s assistant before finding a better job building aviation instruments for the Pioneer Instrument Company of Brooklyn.
Excited by his idea of a truly accurate altimeter, Kollsman left Pioneer in 1928 to start his own company. It began with an initial capitalization of $500 in the garage behind his house in Brooklyn. He then made the rounds of New York City–based watchmakers, for they alone possessed the manufacturing precision and repeatability required to make his design’s miniaturized gears and other precision components.
One finds everything in New York. Kollsman located Swiss craftsmen who could build and repair the finest wristwatches. An agreement was concluded to apply the skills of one area of human endeavor to benefit another. Parts in hand, Kollsman carefully built working prototypes of the sensitive altimeter, as he called it.
Kollsman was ahead of his time. There was no market for his device because aviation was then doing fine with World War I–style altimeters. Although they were inaccurate and indicated differently from one day to the next, those existing devices were fine for telling pilots roughly how high they were in the early days before instrument flying existed.
World War I altimeters had large-diameter faces and a somewhat nautical look. Made of brass or steel with heavy mounting flanges and thick glass faces, they displayed the airplane’s range of operating altitudes in 1,000-foot increments. A single needle set against this closely spaced scale showed the airplane’s approximate height.
The reason that World War I altimeters were so capricious is of course that ambient air pressure changes according to the weather. Balmy high-pressure days made them read too low, whereas stormy conditions gave false indications on the high side.
Kollsman’s sensitive altimeter differed greatly. For starters, it was designed to be accurate within 20 feet or less of actual altitude. Smaller in diameter, this instrument had two indicator needles set against a clockwise scale that read from 0 to 9. Each increment denoted 100 feet, not 1,000 feet. As the airplane climbed, this altimeter’s big needle swept clockwise around and around these increments. Each time it passed 0