Stanley Hiller Jr., whose childhood passion for vehicles led him to design new technology for helicopters while still a teenager and who went on to become a leader in the industry. By the time he was 17 he had come up with the premise that stacking two sets of blades whirring in opposite directions on top of one another was safer and more efficient than the traditional configuration, with one set on top of the aircraft and the other at its tail.

His helicopters were used by the French for jungle rescues in Indochina and by the United States Army in the Korean War. There the helicopters were used primarily for medical evacuation, later becoming familiar to the public through the television series "MASH." At its zenith, his company, Hiller Aircraft, was one of the so-called big four in helicopter production, the others being the Sikorsky Aircraft Company, the Piasecki Helicopter Corporation and the Bell Aircraft Corporation.

Mr. Hiller also ventured into ingenious experiments that led to flights of fancy if not actual flights. One was a flying platform that resembled a manhole cover with a person standing on its surface; one was a collapsible helicopter that could be assembled with bare hands in five minutes. Stanley Hiller designed aircraft that were out of the box.

In 1964 his company was acquired by Fairchild Stratos for about $10 million, but Mr. Hiller remained on board as executive vice president.