P&W's "Formidable" F119 Makes Show Debut

Making its first international airshow appearance here is a full-scale mock-up of the Pratt & Whitney F119-PW-100, the formidable low-bypass augmented turbofan engine which powers the supersonic-cruise F-22 Raptor fighter. The mock-up spends most of its time on the road, giving US Air Force maintainers a glimpse of the future, and it provides a hands-on opportunity to examine the way in which the F119-like its planned derivatives for the Joint Strike Fighter-has been designed for unprecedented ease of maintenance.

Accessories and inspection points on the F119 are arranged "one deep" ­ there is no need to remove one part to reach another. Lines and cables are color-coded. The engine is designed around a small group of standard sockets and wrenches-all the fasteners used in routine maintenance can be installed with those tools.

External fluid lines are made from titanium alloys, for strength and durability, and some lines have been eliminated in favor of passages cast into the magnesium-alloy gearbox case. Line connectors have snap-on collars with spring-loaded fingers, which take the place of cumbersome safety wires and prevent the connectors from twisting loose.

We have all experienced the awkwardness of balancing a heavy object in place with one hand and tightening fasteners with the other. On the F119, components such as the digital engine control boxes are mounted on hanging brackets which hold them in place while the technician secures the built-in fasteners.

One rule is that nothing falls off the engine. Fasteners are permanently retained in place. Pipe and cable brackets and filler and drain caps have wires or chains that keep them attached and are within reach even when they are opened. "Mechanics are teenagers," observes a P&W engineer. "They drop [stuff] on the floor and lose it all the time."
On the F119, operations that usually take hours-such as replacing a control box-can be completed in minutes. The USAF's goal is that the F-22 can be deployed with fewer people and less equipment than the F-15, despite its sophistication.

F119 derivatives power the Boeing X-32 and Lockheed Martin X-35 JSF prototypes, due to make their first flights this spring.