среда, 2 сентября 2015 г.

How the Next-Gen Stealth Bomber Will Work

Shun Specialty Parts

Mechanics at Whiteman Air Force Base gripe about the lack of suppliers for airplane parts—some small firms went out of business 15 years before their parts needed replacing. "Design the system for long-term sustainability," says one B-2 munitions officer. "Don't build anything one-off for the airplane; this is one of the curses of the B-2."

Um, Drop Tanks?

Dangling disposable fuel tanks from a stealth aircraft is seen as heresy because their shapes on the aircraft's exterior can be seen on radar. However, former Air Force Secretary Michael Wynne recently proposed the idea, observing that most of a bomber's flight is spent in uncontested airspace. When the fuel is gone, the aircraft can jettison the empty tanks and restore its stealthy profile, then refuel only on the way home.

Bombers Won't Just Carry Bombs

The next bomber will accommodate exotic weaponry, such as directed energy beams, advanced decoys, and computer viruses. "A platform with terrific penetrating capability and wonderful avionics, from a cyber- warfare standpoint, is a fantastic asset," says aerospace analyst Richard Aboulafia of Teal Group.

Inside the Future Engine

Adaptable Engine

B-2 pilot Capt. Timothy "Scar" Sullivan wants the next-generation bomber to have better fuel economy. Major engine makers such as Pratt & Whitney and GE Aviation are working on variable-cycle engines now. "They're going to be much more adaptive, meaning that they can reconfigure themselves in flight," says Jimmy Reed, P&W's director of advanced programs. To dash, the engine routes air (green) from its turbofan to an outer-shell turbojet, which provides high thrust but is efficient only at high speeds.

Newfangled Blades

GE developed ceramic-matrix composites for use in the hottest sections of its engines, including high- and low-pressure turbine vanes and blades. An engine that can handle hotter air (orange) can produce more thrust.

Digital Controls

A little vectored thrust can go a long way. Wiggling an engine even a few degrees can help sharpen turns and improve performance. All major military-engine makers now connect aircraft engines with flight-control computers, which automatically adjust the exhaust nozzle's direction based on pilot input.

More Air

Modern turbofan engines have two airstreams, core and bypass. An Air Force program developed a design with a third stream of air (blue) that can be routed into the core for extra thrust or to help dilute hot exhaust with cool air to obscure the plane's thermal signature.

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