Design News for Mechanical and Design Engineers

The FJX-2 has about 10% of the number of parts that are normally present in large commercial turbofans. "We concentrated our efforts on component configuration and manufacturing processes that reduce parts count," according to Williams. "We still have same basic components, however, the part count is greatly reduced by designing most elements to provide more than one function," he says. The fan, for example, would normally have individual blades inserted into slots in a machined disk. The FJX-2 has fan blades and disk machined as a single part.

NASA provided design consulting services to Williams International, according to Leo Burkardt, the general aviation propulsion project manager for the Glenn Center. "We performed material characterization, turbomachinery and engine cycle analysis, engine wind tunnel testing, and noise analysis," he says. NASA's work helped make the FJX-2 the world's quietest turbofan engine. It produces only 76 dB at 1,000 ft underneath the engine.

The FJX-2 engine creates a new category of small passenger planes for short trips that are more convenient for passengers than larger commercial airplanes. The FJX-2 will power the Eclipse 500 jet, a new six-passenger aircraft that becomes commercially available in August 2003. Smaller planes like the Eclipse could use the nation's 5,000 public airfields, which are not crowded compared to major airports.

The 14.5-inch diameter engine also produces lower levels of undesirable exhaust emissions, according to Sam Williams. "An airplane designed around the FJX-2, flying the same distance with the same payload as a piston-engine aircraft will have about the same fuel burn," adds Burkardt. "At 13 mpg, the engine's fuel efficiency rivals many of today's sport utility vehicles."