For Release: Dec. 12, 1996

June Malone
Office of Media Services
(205) 544-0034
june.malone@msfc.nasa.gov

RELEASE: 96-188

APPLYING NASA SHUTTLE ENGINE TEST FINDINGS MAY SAVE AIRLINES MILLIONS ON FUEL COSTS

Results from tests aimed at improving the performance of NASA's Space Shuttle engines are expected to save airlines millions of dollars in fuel costs each year.

The tests, performed at NASA's Marshall Space Flight Center in Huntsville, Ala., have led to improvements in the design of a new, more fuel-efficient jet engine for the Boeing 777.

A full, half-percent was gained in energy efficiency -- meaning a savings of hundreds of gallons of fuel per flight and annual savings of millions of dollars -- for the airline industry.

Tests performed at the Marshall's turbine airflow test facility in 1992 were a joint project by NASA and Pratt & Whitney, a leader in commercial and military aircraft engine design and manufacturing.

Analyzing the test results, engineers noticed the information showed the effects of small fluttering "wakes" of gases -- the unsteadiness of gases flowing through the turbine airfoils -- on turbine efficiency. A turbine is a mechanical device used to provide power or thrust in rockets or jet engines. The turbine is similar in concept to a household fan: The fan rotates with blades on a shaft, just as a turbine rotates on a shaft with layers of blades, which are called airfoils.

Engineers explored the existence of an "optimum position" for the turbine airfoils, which could mean less energy to drive the turbines, resulting in lower engine temperatures, longer-lasting hardware, lower maintenance time and lower operational costs.

Marshall and Pratt & Whitney engineers then repeated the initial tests, this time for the engine of the wide-bodied Boeing 777 aircraft, which was to be put into commercial service in 1995.

Stephen Gaddis, project engineer in the Marshall Structures and Dynamics Laboratory where the tests were conducted, explained: "Wakes flowed through the turbine airfoils, coming out high in some places, low in others. We knew if we could align the airfoils or wakes, we could also get the peaks and valleys to align -- all for better turbine efficiency."

The principle is much like one used by competitors in bicycle races: A cyclist will move in behind another racer to benefit from "drafting" created by the front cyclist. The biker in front serves to break the winds' force, so the cyclist in the rear does not have to pedal as hard as the leader.

Pratt & Whitney took these findings and modified their PW-4084 engine for the Boeing 777.

"We had been looking for ways to achieve efficiency improvement," said Frank W. Huber, manager of turbine aerodynamics for Pratt & Whitney's Government Engine Division in West Palm Beach, Fla. "The clocking concept -- the aligning of the airfoils -- was not new, but there was not sufficient data to validate this technique.
"The tests at Marshall Center demonstrated that the concept worked -- clearly showing the benefit of aligning the turbine airfoils," said Huber. "We ultimately found that we could achieve significant improvement in engine performance."

Technology developed by NASA has given Pratt & Whitney and the Boeing Company a competitive edge in world markets, with an aircraft engine that can realize substantial fuel savings.

Today, both government and private industry researchers are using the Marshall test results to fine-tune the large, electric-generating turbines used by America's electric companies, in an effort to save fuel.

VIDEO FILE AVAILABLE: Footage of the Boeing 777 and Shuttle engine testing, and an interview with Stephen Gaddis, NASA engineer at Marshall, discussing turbine efficiency is available to illustrate this subject. If interested, please call the Marshall Public Affairs office at (205) 544-0034.

NOTE FOR EDITORS: Marshall's Technology Transfer Office is responsible for the direct transfer of NASA-inspired ideas and solutions to businesses throughout the Southeast. The office also interacts with companies around the country providing assistance for a variety of technology challenges. For more information about NASA's Technology Transfer Program and the Federal government partnering with industry, call 1-800-USA-NASA.