Williams FJ22

The Williams FJ22 was a small turbofan engine that was being developed by Williams International for very light jet (VLJ) aircraft applications.

Development

Williams International had been building small turbofan engines for cruise missile applications since the 1960s, and had successfully entered the general aviation market in 1992 with the FJ44 engine. That same year, NASA initiated a program, Advanced General Aviation Transport Experiments (AGATE), to partner with manufacturers and help develop technologies that would revitalize the sagging general aviation industry. In 1996, Williams joined AGATE's General Aviation Propulsion (GAP) program to develop a fuel-efficient turbofan engine that would be even smaller than the FJ44. The result was the FJX-2 engine.

Williams then contracted with Burt Rutan's Scaled Composites to design and build the Williams V-Jet II, a Very Light Jet (VLJ) to use as a testbed and technology demonstrator to showcase the new engine. The aircraft, powered by two interim FJX-1 man-rated version of Williams' cruise-missile engine, debuted at the 1997 Oshkosh airshow.

In 1998, Williams joined with Eclipse Aviation to develop an FAA-certified version of the FJX-2 to be used on the Eclipse 500 VLJ. The new EJ22 powered the Eclipse 500 prototype on its first flight in 2002, but numerous significant technical problems with the EJ22 subsequently grounded the plane and prompted Eclipse Aviation to eventually terminate its relationship with Williams International. Renamed the FJ22, development work was halted shortly thereafter, and the engine never came close to FAA certification.Fact|date=June 2008

pecifications

The engine is a convert|700|lbf|abbr=on thrust class medium-bypass ratio turbofan with a fan diameter of about 15 inches. Length is convert|41|in|mm, and basic engine weight was 85 pounds. At the time of its testing in June 2001, it demonstrated a thrust-to-weight ratio of 8.2, which claimed to be better than the highest thrust-to-weight ratio of a commercial jet engine. The main compressor has 5 stages, and weighs only convert|1.22|lb|abbr=on.Cite web|url=http://www.grc.nasa.gov/WWW/AST/GAP/img/hpcomp.jpg|title=FJ44 compressor image|accessyear=2007|accessmonthday=November 21|publisher=National Aeronautics and Space Administration|author=NASA] Engine layout was a three-spool arrangement, with all three compressors being axial. This was a departure from previous Williams engines, which had all used centrifugal high-pressure compressors. A reverse flow combustor and a mixed exhaust were other features.

References

ources

* [http://www.airventuremuseum.org/collection/aircraft/Williams%20V-Jet%20II.asp EAA AirVenture Museum]
* [http://www.grc.nasa.gov/WWW/AST/GAP/GAPnews.htm NASA GAP General Aviation Propulsion program final report with pictures]