Drucella Andersen
Headquarters, Washington, D.C.                                                 
June 3, 1993
(Phone:  202/358-4727)

Michael Mewhinney
Ames Research Center, Mountain View, Calif.
(Phone:  415/604-9000)


RELEASE:  93-103

NASA TESTING NEW, POWERFUL "DUCTED FAN" ENGINE FOR CIVIL JETS

     NASA has begun testing a powerful, new engine developed for 
large subsonic passenger jets that could cut fuel consumption 10 to 
12 percent and significantly reduce engine noise.

     "By the turn of the century, the Advanced Ducted Propulsor 
(ADP) should be ready for use in 300-to-700 seat commercial 
transport aircraft," said Dr. Clifton Horne, Project Director at 
NASA Ames Research Center, Mountain View, Calif., site of the 
testing.  

     The ADP features a large, variable-pitch fan system, a 40,000 
horsepower fan-drive gear system and a new, high-speed, 
low-pressure turbine.  The engine has a maximum forward thrust of 
more than 50,000 pounds.  

     The ADP's variable-pitch fan system, which is nearly 10 feet 
(3 meters) in diameter, places its 18 fan blades in the most 
efficient position for take off, cruising and reverse thrust.  

     "This ends the need for thrust reversers normally used to slow 
down an aircraft after landing," Horne said.  "Elimination of 
thrust reversers can provide weight, reliability and cost benefits 
unattainable with conventional fixed-blade turbofans."

     The joint NASA/Pratt & Whitney project is part of NASA's 
research program in subsonic aircraft technology to develop 
technologies, in cooperation with the aerospace industry, that make 
possible significant improvements in aircraft performance and 
ensure that U.S. air transportation remains competitive worldwide.
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     The full-size ADP "demonstrator" engine was developed by Pratt 
& Whitney, a division of United Technologies Corp., Hartford, 
Conn., with Motoren-und Turbinen-Union of Munich, Germany, and Fiat 
Avio of Turin, Italy  

     Turbojet engines generate thrust by pushing high speed air 
through the compressor, combustion chamber and turbine.  In a 
turbofan, the turbine also drives a large fan.  The fan produces 
thrust more efficiently and quietly by pushing through more air at 
lower speeds.

     Tests in the NASA wind tunnel will continue 9 hours a day for 
12 weeks.  
The goals include confirming the engine's thrust reverse 
capability. 

     "Tests will center on simulated landing conditions, with 
primary emphasis on confirming thrust reverse under variable pitch 
in 120-to-140-knot winds," Pete Zell, Ames' Test Director said.

     ADP is the largest engine ever tested in Ames' National 
Full-Scale Aerodynamics Complex (NFAC) wind tunnel.  "The NFAC is 
the only facility capable of simulating flight conditions and 
thrust reversal for this engine," said Horne. 

     Pratt & Whitney first tested the ADP last fall at its West 
Palm Beach, Fla., facility.  Those tests confirmed the engine's 
operation without forward wind speed.  Pratt & Whitney tested a 
one-seventh-scale model of the ADP at NASA's Langley Research 
Center, Hampton, Va., in 1992 and at Lewis Research Center, 
Cleveland, in 1991.

                               -end-

NOTE TO EDITORS:  A video clip showing the ADP in Ames' 
40-by-80-foot wind tunnel is available to media by calling 
202/358-1733.  Still photos also are available to the media by 
calling 202/358-1900.

Color:                            B&W
93-HC-194                   93-H-210