Advanced Turbdprdps. and Laminar Fldw

1987 Washington Post headline read, “The Aircraft of the Future

1 las Propellers on It."’ To many, this sounded like heralding “the reincarnation of silent movies.”2 Why would an “old technology” ever be chosen over a modern, new, advanced alternative? How could propeller technology ever supplant the turbojet revolution? Mow could the “jet set mind-set” of corporate executives who demanded the prestige of speed and “image and status with a jet” ever be satisfied with a slow, noisy, propeller-driven aircraft?’ A Washington Times correspondent predicted that the turbojet would not be the propulsion system of the future. Instead, future airline passengers would see more propellers than jets, and if “Star Wars hero Luke Skywalker ever became chairman of a Fortune 500 com­pany. he would replace the corporate jet with a … turboprop.”1 It appeared that a turboprop revolution was underway.

The Advanced Turboprop Project was one of the more radical and risky projects in the ACEE program, but it offered some of the highest fuel-efficiency rewards. NASA planners believed that an advanced tur­boprop could reduce fuel consumption by 20 to 30 percent over existing turbofan engines while maintaining comparable performance and passenger comfort at speeds up to Mach 0.8 and altitudes up to 30.000 feet. These ambitious goals made the turboprop project controversial and challenging. Clifton von Kann succinctly summed up these concerns to [299] [300] [301] [302]

Barry Goldwater during his Senate testimony, when he said that of all the proposed projects, “the propeller is the real controversial one.”1′

The Advanced Turboprop was not the only revolutionary, long-range technology in the ACEE program. Some speculated as early as the 1960s that Laminar Flow Control would be a “harbinger of potential revolution in the plane-making business.”[303] [304] The Laminar Flow project was based upon an airplane wing that seemed to “breathe” air. When engineers began achieving significant successes with this technology in the early 1960s, they knew they were on the cusp of a major advance. Many wondered if the resulting aircraft with breathable wings would be able to fly for days— and not just hours—without refueling. Or, more realistically, a nonstop flight from New York to Tokyo might be offered to commercial travelers. First flight-tested in 1963, the “air-inhalation system" was considered “the most promising innovation since the jet engine.”[305] Because of the Vietnam war. the military suspended further work on this technology, but it was resurrected in the 1970s and became the most promising ACEE project in terms of fuel efficiency.

Lewis Research Center managed the Advanced Turboprop Project, and Langley Research Center headed the Laminar Flow Control program. Although the two NASA ACEE projects had little interaction with each other, they shared some important similarities. First, they represented revolutionary potential in fuel efficiency, with the turboprop promising up to 30 percent and laminar flow up to 40 percent. Second, achieving these gains required commitment from the very conservative American airlines industry to a fundamental and radical new aircraft design and pro­pulsion system. Finally, both programs required a long-term commitment to research, and both had risky and uncertain futures. For these reasons, industry alone would never risk the funds to research their potential, but the Government support through NASA offered an appropriate venue for exploring technology that could have a revolutionary impact on the airlines industry. The questions at the start of the program were: Could NASA engi­neers achieve success and develop these new fuel-efficient technologies? And. if they could, would the airlines industry accept the challenge and open its arms to incorporate the technology in its new fleet of aircraft?