Engine Development

The primary propulsion systems being designed for the JSF Program are derivatives of the F119-PW-100 engine that powers the F-22 Raptor. The propulsion system concepts for both Weapon System Contractors (WSCs) use a P&W F119 core (compressor, combustor and high pressure turbine). The F119, a low-bypass ratio turbofan, is in the 35,000 lb-thrust class. The propulsion system concepts for the Boeing and Lockheed Martin configurations utilize new fan and low-pressure turbine (LPT) designs, which are based on F119 designs, materials and processes. The JSF119 engines were based on the F119 for commonality and cost reduction issues. These F119-derivative engines are in the 40,000 lb-thrust class. For the demonstrator program, both concepts take advantage of F119 controls and externals as much as practical, but each aircraft will use new nozzles.

P&W JSF119 engine and relationship to the F-22/F119

P&W began the CDP by completing the preliminary design of the two selected engines, the JSF119-PW-614 for Boeing and the JSF119-PW-611 for Lockheed Martin. P&W then began extensive facility modifications, altering test stands for carrier (CV) and conventional take-off and landing (CTOL) engines as well as for STOVL tests of the full-up propulsion systems (i.e., with the Roll-Royce (RR) and/or Rolls-Royce Allison lift components), at P&W's West Palm Beach, Florida plant. These facility modifications resulted in a total of four test stands for CV/CTOL tests and one for STOVL operations as well as two tests stands for STOVL operation with multi-component thrust measurement systems. Facility modifications were also required at the Air Force's altitude test facilities at the Arnold Engineering Development Center (AEDC) in Tullahoma, Tennessee, to accommodate the JSF119 engines, since even the CV/CTOL versions are much different than the F-22/F119 engine.

Lockheed and Boeing propulsion systems. The blue indicates the turbomachinery. (Click here for more CAD images and movies)

JSF119 engine fabrication began in March 1997 with the machining of the titanium billet that would become the first stage fan integrally bladed rotor (IBR). Engine assembly began when the first JSF compressor section was completed on 19 September 1997. The first JSF core was completed on 28 January 1998 at P&W's manufacturing plant in Middletown, Connecticut.

The engine test program is designed to clear the engines for flight in the shortest amount of time as possible. P&W is building two developmental engines, two qualification engines and two flight-test engines for the Boeing JSF design, and a similar program for Lockheed Martin, with well over 1000 hours of ground test time for each WSC. Engine testing began on 11 June 1998 with the commencement of testing on the Lockheed Martin SE611; this was followed 10 days later with the Boeing SE614. Although two months behind the extremely aggressive contract goal date, the two engine designs were brought to test within 18 months of contract award through close coordination between the WSCs, P&W, and their vendors.

Boeing STOVL engine with 2D nozzle on test stand at P&W. The large sieve-like device and the long duct on the front of the engine serve as protection from the ingestion of foreign objects.

These initial tests were conducted at P&W's West Palm Beach facility and included component performance evaluations, compression system stability demonstrations, vibration surveys, operating system functional verification, and control software verification. The JSF119 engines were then instrumented for simulated altitude testing at AEDC. In over 120 hours of combined initial testing, the Boeing JSF119-614 and Lockheed Martin JSF119-611 engines demonstrated component efficiencies higher than anticipated, turbine temperatures lower than predicted, and very low vibration levels.

Lockheed Martin STOVL engine and Lift Fan undergoing testing. The bottom of the Lift Fan is visible between the two engine intake ducts, and discharges into exhaust ducting.

The STOVL engines began testing in mid-November 1998 on P&W's unique test stands that have been designed to measure forces in all directions to properly characterize STOVL engine operation and its relationship with the aircraft vehicle management system. By the end of 1998, P&W had four JSF119 engines under test, having accumulated a total of approximately 200 hours. Testing has continued with approximately 2000 hours of combined ground testing completed as of early 2000.