Williams International's EJ22 Engine
Focus of Technical Interest at NBAA

Williams also comes to the show as a very well established player in the business jet market, with two new applications approaching certification.

The EJ22 is one of several production engines to be developed from the FJX-2, which Williams has developed since 1996 with the help of funding from the NASA General Aviation Propulsion (GAP) program. The EJ22's development is being funded by Eclipse's financial backers, and it is specifically an Eclipse engine. The FJ22 is a turbofan, available to other manufacturers, and the family also includes the TSX-1 turboshaft and the TSX-2 turboprop.

The EJ22 and FJ22 share many components, including the tiny six-stage axial compressor, with its rotor machined from a single piece of metal. The primary difference, and one of the main technical novelties in the Eclipse engine, is that the EJ22 is integrated to an unusual degree into the airplane and its systems. Although details are closely held, the fuel pump and control systems and the electrical system of the airplane and the engine are combined. For example, the engine control system may be located within the airplane and combined with the flight controls.

In the Eclipse, as in Williams' V-Jet II technology demonstrator, the engines are installed close together in the tail. The result is that the tapering fuselage acts as an inertial separator, throwing hail and birds away from the engine inlets. The engine will be designed to meet standard certification requirements for bird and ice ingestion, but the design should reduce the risk of damage.

Tests this year showed that the high-pressure compressor, which was considered to be the highest-risk component of the engine, was running within one point of its design efficiency. Even at this early stage, the engine has shown low vibration levels and has proven to be mechanically sound. The 500 shp turboprop engine started tests in March, and is running as a complete powerplant with a propeller attached. Williams reports strong interest in the engine's turboshaft derivative.

Meanwhile, Williams' 1,200 to 1,500 pounds thrust FJ33 turbofan made its first run in late July. The first engine, built on production tools at the company's Ogden, UT, facility, met its thrust targets and beat its fuel consumption goals on its initial run. Company chairman and CEO Dr. Sam Williams describes the FJ33 as "a step beyond the FJ44" in terms of thrust-to-weight ratio and performance. The engine is due to be certificated in 2002 and has been selected for the Century Aerospace CA-100 and the Aerostar FJ-100.

In April, Williams received FAA type certification for the latest and most powerful development of the FJ44 engine. The 2,400 pounds thrust FJ44-2C is designed for the stretched Cessna Citation CJ2. According to the engine company, successful testing of the ­2C engine at higher thrust levels will lead to greater endurance and lower maintenance costs for other versions of the engine. The ­2C also includes an integrated fuel delivery unit, which combines the functions of a hydromechanical fuel control with a fuel pump. Two FJ44-powered aircraft are due to pass significant milestones this year, with certification of the Raytheon Premier and the first flight of the FAA-conforming, production-model Sino Swearingen SJ30-2.

By Bill Sweetman