Williams International FJ22
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The Williams FJ22 was a small turbofan engine that was being developed by Williams International for very light jet (VLJ) aircraft applications.
[edit] Development
Williams International had been building small turbofan engines for cruise missile applications since the 1950s, and had successfully entered the general aviation market in the late 1980s with the FJ44 engine. In 1992, 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.
The engine is a 700 lbf thrust class high bypass ratio turbofan with a fan diameter of about 14in. Length is 41in and basic engine weight was 85 lb. At the time of its testing in June 2001, it demonstrated a thrust to weight ratio of 8.2 which is claimed to be better than the highest thrust to weight ratio commercial jet engine. Design goals included single lever power control and fuel burn less than comparable piston engines. The main compressor has 5 stages and weighs only 1.22 lbs picture here. Engine layout is to be a three-spool arrangement. A reverse flow combustor and a mixed exhaust are other features.
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 and engine were debuted at the 1997 Oshkosh airshow.
The production version of the engine, the EJ22 flew on the prototype Eclipse 500 VLJ (which had evolved from the V-Jet II). Signifiant technical issues with the EJ-22 such as fire, vibrations and lack of surge margins prompted Eclipse Aviation to terminate its relationship with Williams International. Following bids from two major engine manufacturers, Eclipse selected the 900 lbf thrust Pratt & Whitney PW610F. More recently, the Williams engine has become known as the FJ22.
According to Williams International's announcements at the 2006 National Business Aviation Conference, the FJ22 production line has been suspended indefinitely. This engine did have great potential but fell behind schedule and was dropped from the Eclipse program. Without any funding, what potentially could have become a revolutionary turbofan for small jets had to be scrapped altogether.
