Hot Race

Month ago the U. S. War Department planked out $25,009,388 for a whopping rush order of airplane engines. To Allison Engineering Co., a newcomer in high-powered aeronautics, went the fattest slice: $15,080,261. Old-established Wright Aeronautical Corp. and Pratt & Whitney (already fat with Army contracts) came off second and a poor third (Wright: $8,975,317; Pratt & Whitney $953,810). Reason: Army men favored the Allison 1,200-h.p. engine (TIME, Jan. 30), whose twelve inline cylinders, snug as a whippet's ears, made it the last word in streamlined high-output power.

Ever since Colonel Lindbergh flew one across the Atlantic in 1927, most U. S. aeronautical engineers have been developing air-cooled, radial engines with cylinders raying out like huge wheel-spokes around a short, chunky crankshaft. But as power was increased, radial engines grew so bulky that they dragged on high-speed planes.

Last week, however, it was Pratt & Whitney's turn to smile all over its corporate face. Over its East Hartford, Conn, plant roared a Vultee A19 motored by an engine of the old radial, air-cooled type that was half again as powerful as the Allison. Weighing slightly less per horsepower than the Allison, it could fit into small pursuit planes as snugly as a cartridge in a rifle breech.

Their pride & joy resembled the 14-cylinder, 1,200-h.p. Twin-Wasp motor but had four more cylinders, some 50% more horsepower, about the same dimensions. Secret-of-success: through trial & error engineers had learned to cool high-powered air-cooled engines more efficiently, thus were able to clump more cylinders around a single crankshaft. Better cooling also made it possible to increase cylinder pressures, step up speed of piston strokes.

Meantime all plane makers heard heartening news. In 1922, when British Aeronautic Engineer Frederick Handley Page took out U. S. patents on his wing slot, a safety device to control spinning and stalling,* he demanded a fancy price for installation: about 5% of the plane's cost (as much as $25,000 for a DC-4). Too costly for most plane makers who hesitated to devise variants lest they infringe on British patents, wing slots were rarely used. Many a flier crashed who might otherwise have been saved.

Last week Engineer Page's patents expired, wing slots became available to everybody.

*Which occurs when, as a result of climbing too steeply, the smooth flow of air over wing tops becomes disturbed, destroys their lifting power. Wing slots admit a stream of air to the wing top through vents in the leading edge of the wings.

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