Jim Cast
Headquarters, Washington, DC          December 12, 1996
(Phone:  202/358-1779)

June Malone
Marshall Space Flight Center, Huntsville, AL
(Phone:  205/544-0034)

RELEASE: 96-254

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

     Results from tests aimed at improving the performance of 
NASAÕs 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, AL, 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 MarshallÕs 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 that 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, 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, less 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 Marshall's 
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 & WhitneyÕs Government Engine Division 
in West Palm Beach, FL.  "The clocking concept -- the 
aligning of the airfoils -- was not new, but there were not 
sufficient data to validate this technique."

     "The tests at Marshall 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, 
electricity-generating turbines used by America's electric 
companies, in an effort to save fuel.

                            -end-