THE VIRGINIAN-PILOT
Copyright (c) 1997, Landmark Communications, Inc.
DATE: Tuesday, January 28, 1997 TAG: 9701280249
SECTION: LOCAL PAGE: B4 EDITION: FINAL
SOURCE: ASSOCIATED PRESS
DATELINE: HAMPTON LENGTH: 77 lines
NASA engineers say technology that smooths the passage of air over airplane wings is an aerodynamic breakthrough that will save airlines and the flying public billions of dollars in fuel costs.
But airplane manufacturers say they have no plans to use ``laminar flow control'' technology unless there is another energy crisis or pressure from European air carriers increases.
By smoothing the flow of air over wings, airplanes use up to 10 percent less fuel, said Jeffrey Lavell, project manager for supersonic laminar flow experiments at NASA Langley Research Center.
``The whole idea for doing this is to make an airplane fly more efficiently,'' Lavell said.
In the past 20 years, NASA and industry engineers have shown that laminar flow control is possible using a vacuum system that sucks air through tiny holes in the surface of a plane's wings.
But such airplane makers as Boeing and McDonnell Douglas haven't taken steps to use laminar flow technology in their airplanes.
Boeing has decided not to use it because it may be too expensive and may cause problems in manufacturing and maintenance, said spokeswoman Mary Jean Olsen.
The engineers who helped develop the technology say manufacturers are simply conservative by nature, unwilling to try something new if they don't have to - even something that could save billions for their customers.
The quest for laminar flow began at Langley in the 1920s. In wind tunnels, engineers saw that the air passing over a wing remains smooth for a few inches before disintegrating into turbulent swirls and eddies that put drag on a plane in flight.
In the 1940s, engineers thought they could prevent those swirls and eddies by sucking a small amount of air into the wing, through tiny holes. But the tiniest holes they could cut 50 years ago weren't tiny enough and actually caused more turbulence, Lavell said.
Then laser cutting tools made truly tiny holes possible starting in the 1970s.
The wing surfaces used in NASA Langley's laminar flow experiments contain thousands of holes per square inch, said Mike Fischer, the principal investigator.
``It looks solid until you hold it up to the light,'' Fischer said.
The energy crisis of the 1970s prompted airplane companies to begin experimenting with laminar flow, and by the late 1980s the Air Force, NASA Langley and Boeing had successfully used a laminar flow system on a Boeing 757.
The final technological barrier to laminar flow was overcome last year, when a group led by NASA achieved extensive laminar flow on an F-16 fighter plane at 1,400 mph.
But despite four years of work and last year's successful tests, the final designs for that plane won't include laminar flow technology, Lavell said.
Many questions remain about laminar flow control. To date, it has been achieved using special surfaces slipped over top conventional wings; engineers don't yet know how those surfaces would actually be integrated into the wing's structure.
The engineers who developed laminar flow control believe one of two things will have to happen before U.S. airplane manufacturers will pursue their technology.
In the event of another energy crisis such as the Arab oil embargo, the fuel savings from laminar flow will become more appealing, said Lavell.
American companies could also be forced to adopt the technology if foreign competitors begin using it.
The chief competitor to American aircraft makers, Europe's Airbus Industrie, is reportedly working on laminar flow and has built the world's third laminar flow wind tunnel (the other two are in the United States, one at Langley).
``That could turn the tide very quickly, because then it becomes a matter of competitiveness,'' said one developer.
KEYWORDS: NASA LANGLEY RESEARCH CENTER