Williams International FJ22
Encyclopedia
The Williams FJ22 was a small turbofan
engine that was being developed by Williams International
for very light jet
(VLJ) aircraft applications.
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 and designated the FJX-2 engine.
Initially, Williams 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
. Development of the FJX-2 engine progressed, most of the design work was completed during 1998 with initial prototype parts being delivered in the second quarter of that year. The FJX-2 engine was designed with many experimental systems and manufacturing processes to minimize parts count and lower production costs and having a bypass ratio of 4:1.http://www.docstoc.com/docs/1084022/The-General-Aviation-Propulsion-(GAP)-Program As a result, result there were many technical difficulties and failures of the initial prototype hardware. However, subsequent re-designs and the incorporation of more conventional systems resulted in the engine eventually meeting the NASA requirement of 700 lbf (3,113.8 N) thrust. The program ultimately culminated with altitude testing at the NASA Glenn Research Propulsion Systems Laboratory from March - April 2000.
In 2000, Williams joined with Eclipse Aviation to develop an FAA-certified version of the FJX-2, designated the EJ22, to be used on the Eclipse 500 VLJ due for first flight in June 2002. This would be an unprecedentedly short period of time to develop a new man-rated turbofan engine. The new EJ22 powered the Eclipse 500 prototype on its first flight in the Summer of 2002.
Eclipse initially required the engine to produce 770 lbf (3,425.1 N) thrust, exceeding the 700 lbf (3,113.8 N) rating of the FJX-2 by 10%. This was only the first of a large number of continuously changing requirements Eclipse would demand. Ultimately, numerous technical problems with the EJ22, significantly compounded by the frequently changing requirements of Eclipse Aviation, grounded the plane and prompted Eclipse Aviation to terminate its relationship with Williams International in late 2002. Following termination of the contract, development work was halted shortly thereafter and the engine never came close to FAA certification..
To achieve the required TSFC, the EJ22 turbofan was designed as a three spool engine having a fan, two axial compressors and three expansion turbines. As a result, the engine was significantly more complicated than any prior Williams International engine. While very impressive on the test stand, the EJ22 proved quite temperamental during the two short years of its development process and it was frequently subject to problems starting, overheating, part failures and various subsystem issues. While most of problems may have eventually been resolved during a normal development program, the shortened development period, and the frequent changes by Eclipse, proved to be unsurmountable obstacles.
Turbofan
The turbofan is a type of airbreathing jet engine that is widely used for aircraft propulsion. A turbofan combines two types of engines, the turbo portion which is a conventional gas turbine engine, and the fan, a propeller-like ducted fan...
engine that was being developed by Williams International
Williams International
Williams International is a manufacturer of small gas turbine engines based in Walled Lake, Michigan, United States. It produces jet engines for cruise missiles and small jet-powered aircraft.- History :...
for very light jet
Very Light Jet
A very light jet, entry-level jet or personal jet, previously known as a microjet, is a category of small jet aircraft approved for single-pilot operation, seating 4-8 people, with a maximum take-off weight of under...
(VLJ) aircraft applications.
Development
Williams International had been building small turbofan engines for cruise missileCruise missile
A cruise missile is a guided missile that carries an explosive payload and is propelled, usually by a jet engine, towards a land-based or sea-based target. Cruise missiles are designed to deliver a large warhead over long distances with high accuracy...
applications since the 1960s, and had successfully entered the general aviation
General aviation
General aviation is one of the two categories of civil aviation. It refers to all flights other than military and scheduled airline and regular cargo flights, both private and commercial. General aviation flights range from gliders and powered parachutes to large, non-scheduled cargo jet flights...
market in 1992 with the FJ44
Williams FJ44
-External links:*...
engine. That same year, NASA
NASA
The National Aeronautics and Space Administration is the agency of the United States government that is responsible for the nation's civilian space program and for aeronautics and aerospace research...
initiated a program, Advanced General Aviation Transport Experiments
Advanced General Aviation Transport Experiments
The Advanced General Aviation Transport Experiments project was a consortium of NASA, the FAA, the general aviation industry and a number of universities which was shut down in December 2001. Its goal was to create a Small Aviation Transportation System as an alternative to short-range automotive...
(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 and designated the FJX-2 engine.
Initially, Williams contracted with Burt Rutan
Burt Rutan
Elbert Leander "Burt" Rutan is an American aerospace engineer noted for his originality in designing light, strong, unusual-looking, energy-efficient aircraft...
's Scaled Composites
Scaled Composites
Scaled Composites is an aerospace company founded by Burt Rutan and currently owned by Northrop Grumman that is located at the Mojave Spaceport, Mojave, California, United States...
to design and build the Williams V-Jet II
Williams V-Jet II
The Williams V-Jet II was designed and built by Burt Rutan's Scaled Composites for Williams International as a test bed and demonstrator aircraft for Williams' new FJX-2 turbofan engine.- Development :...
, a Very Light Jet
Very Light Jet
A very light jet, entry-level jet or personal jet, previously known as a microjet, is a category of small jet aircraft approved for single-pilot operation, seating 4-8 people, with a maximum take-off weight of under...
(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
Oshkosh Airshow
EAA AirVenture Oshkosh is America's largest annual gathering of aviation enthusiasts held each summer at Wittman Regional Airport in Oshkosh, Wisconsin, United States....
. Development of the FJX-2 engine progressed, most of the design work was completed during 1998 with initial prototype parts being delivered in the second quarter of that year. The FJX-2 engine was designed with many experimental systems and manufacturing processes to minimize parts count and lower production costs and having a bypass ratio of 4:1.http://www.docstoc.com/docs/1084022/The-General-Aviation-Propulsion-(GAP)-Program As a result, result there were many technical difficulties and failures of the initial prototype hardware. However, subsequent re-designs and the incorporation of more conventional systems resulted in the engine eventually meeting the NASA requirement of 700 lbf (3,113.8 N) thrust. The program ultimately culminated with altitude testing at the NASA Glenn Research Propulsion Systems Laboratory from March - April 2000.
In 2000, Williams joined with Eclipse Aviation to develop an FAA-certified version of the FJX-2, designated the EJ22, to be used on the Eclipse 500 VLJ due for first flight in June 2002. This would be an unprecedentedly short period of time to develop a new man-rated turbofan engine. The new EJ22 powered the Eclipse 500 prototype on its first flight in the Summer of 2002.
Eclipse initially required the engine to produce 770 lbf (3,425.1 N) thrust, exceeding the 700 lbf (3,113.8 N) rating of the FJX-2 by 10%. This was only the first of a large number of continuously changing requirements Eclipse would demand. Ultimately, numerous technical problems with the EJ22, significantly compounded by the frequently changing requirements of Eclipse Aviation, grounded the plane and prompted Eclipse Aviation to terminate its relationship with Williams International in late 2002. Following termination of the contract, development work was halted shortly thereafter and the engine never came close to FAA certification..
To achieve the required TSFC, the EJ22 turbofan was designed as a three spool engine having a fan, two axial compressors and three expansion turbines. As a result, the engine was significantly more complicated than any prior Williams International engine. While very impressive on the test stand, the EJ22 proved quite temperamental during the two short years of its development process and it was frequently subject to problems starting, overheating, part failures and various subsystem issues. While most of problems may have eventually been resolved during a normal development program, the shortened development period, and the frequent changes by Eclipse, proved to be unsurmountable obstacles.