Engines

The F-22 incorporates a pair of new, higher thrust-to-weight engines, the Pratt & Whitney F119-PW-100, which is designed for efficient supersonic operation without afterburner (called supercruise), and with increased durability over current engines. Advanced technologies incorporated in the F119 include integrated flight-propulsion controls and two-dimensional, thrust-vectoring engine nozzles, which will give the F-22 unprecedented aircraft maneuverability. Development of the F119 was conducted at Pratt & Whitney's West Palm Beach, FL, facility, while production takes place at the company's factories in Middletown, CT. Pratt & Whitney built 27 flightworthy engines during EMD.

Designed for efficient supersonic operation without afterburner use and with increased durability over today's engines, the F119 is a very high thrust-to-weight ratio engine. Advanced technologies in the F119 include integrated flight-propulsion controls and two-dimensional, thrust-vectoring engine nozzles. The F119 incorporates technology advances developed and verified in joint U.S. Air Force/Pratt &Whitney research programs and for other advanced fighter engines. It was designed using the "integrated product development" approach to ensure a balance between performance, safety and reliability, maintainability and low life-cycle cost. In addition, it has significantly fewer and more durable components than previous fighter engines.

The F119-PW-100 is a revolutionary advance in fighter aircraft propulsion. The F119 engine develops more than twice the thrust of current engines under supersonic conditions, and more thrust without afterburner than conventional engines with afterburner.

Each F-22 will be powered by two of these 35,000-pound-thrust-class engines. By comparison, the engines powering the Air Force's current F-15 and F-16 fighters have thrust ratings ranging from 23,000 to 29,000 pounds.

Jet engines achieve additional thrust by directly injecting fuel at the engine exhaust. The process, called afterburner, gives the aircraft a rocket-like boost as the fuel ignites in the exhaust chamber. The tradeoff is higher fuel consumption, a greater amount of heat, and consequently, greater visibility to the enemy.

The F119 can push the F-22 to supersonic speeds above Mach 1.4 even without the use of afterburner, which gives the fighter a greater operating range and allows for stealthier flight operation. The product of more than 40 years' research into high-speed propulsion systems, the F119 is proof that high-technology doesn't have to be complicated.

Performance of the F119 engine has generally been excellent in testing. Full-scale airframe static testing and the first of three (originally four) planned fatigue lifetimes of testing have been completed and the second fatigue life testing is nearly complete. The program now plans to complete three fatigue lifetimes prior to the completion of the ongoing engineering and manufacturing development phase in November 2005. Expansion of flight test into the high-speed, high-G load regions of the performance envelope is ongoing.

F119/F-22 Engine Nozzle

The F119 engine nozzle for the F-22 is the world's first full production vectoring nozzle, fully integrated into the aircraft/engine combination as original equipment.

The two-dimensional nozzle vectors thrust 20 degrees up and down for improved aircraft agility. This vectoring increases the roll rate of the aircraft by 50 percent and has features that contribute to the aircraft stealth requirements.

Heat-resistant components give the nozzles the durability needed to vector thrust, even in afterburner conditions.

With precision digital controls, the nozzles work like another aircraft flight control surface. Thrust vectoring is an integrated part of the F-22's flight control system, which allows for seamless integration of all components working in response to pilot commands.

The nozzle is manufactured at Pratt & Whitney's West Palm Beach facility, home to the company's military engine design and prototype construction.

Source: Globalsecurity.org