B-52 Stratofortress will fly into the future with new nacelles and struts

Collins Aerospace is perfectly positioned to extend the power of the B-52’s propulsion system

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B-52 nacelles

In 1952, Rohr Aircraft Corporation – now part of Collins Aerospace – was selected to provide nacelles and struts for Boeing’s new B-52 strategic bomber, commissioned by the United States Air Force (USAF). How proud those employees must have been to take part in such an innovative program. And how excited would they be to know that the current fleet of 76 B-52H Stratofortress bombers – the eighth generation of the aircraft – is set to be updated and outfitted with new propulsion systems that can keep the aircraft flying into the year 2050 and beyond – a whopping seven decades later?

Introducing the B-52 Commercial Engine Replacement Program

The update will come as part of an $2.6 billion commercial engine replacement program (CERP) that will replace the Pratt & Whitney TF33 engine that has powered the bomber since the 1960s. According to the Air Force Global Strike Command and Air Force Materiel Command, the propulsion-system upgrade is expected to result in a 30 percent gain in fuel efficiency and sharply reduced maintenance requirements.

Back in the 1950s when the cutting-edge B-52 bomber was introduced, Rohr was selected to design and produce propulsion system components including the aircraft’s nacelle, pylon, engine mount, aft fuselage and other systems. This was no easy task given the unique configuration on this new platform. For one thing, in an era when most aircraft were still propeller-driven, the B-52 was jet-powered – with each aircraft featuring eight Pratt & Whitney turbojet engines, each producing 10,000 pounds of thrust on earlier models and 17,000 pounds of thrust on the latest model.

Adding to the complexity, the configuration featured a unique twin-engine "pod" layout – two twin-engine nacelles under each massive wing. This called for innovation. Specifically, it required the design of propulsion system components that were not only easy to service in field conditions, but also met the demanding performance requirements of Boeing.

Providing nacelles and struts for every B-52 to date

Fast forward to today, and Collins Aerospace is the only company that can say it has made every single nacelle and every single strut for every B-52 that has ever flown.

"We've been on every B-52 variant to date, producing 5,952 nacelles and 2,976 struts over the years," said Marc Duvall, president, Aerostructures, Collins Aerospace. "We understand nacelles and how to efficiently and dependably manufacture them to the standards and schedules required by Boeing and the Air Force.”

Bringing manufacturing expertise to the table

The current CERP calls for the same propulsion-system architecture so as to match the aerodynamics, center of gravity, thrust line and wing loading from the aircraft’s original design. And given that the B-52 weighs approximately 185,000 pounds and is more than 159 feet long and 40 feet tall, manufacturing challenges abound. But Collins understands the complexity of the uniquely contoured twin-pod nacelle and how to efficiently manufacture it with a high degree of quality and dependability.

Beyond the design and manufacture of the original B-52 nacelle and strut systems, Collins Aerospace has produced a steady stream of primary propulsion-system components for numerous aircraft platforms. In commercial aviation, these range from the Boeing 707 to the 787, and the Airbus A300 to the A350. In the military segment, the portfolio includes the Lockheed C-141, C-5 Galaxy, C-130 Hercules and P3 Orion, among others.

And just as important, we have a long-standing history in integrating our nacelle systems with Rolls Royce engines.

Keeping the bomber flying into the future

A number of other upgrades are being undertaken for the B-52 in 2021, including a replacement of its radar, connectivity upgrades and a new digital backbone for the aircraft. Recently Collins’ Mechanical Systems business unit earned the opportunity to supply the next generation of wheels and brakes to help the aircraft take off and land safely.

“When you look at our long history with the B-52 program, decades of experience manufacturing structural elements, our existing relationship with Boeing and our proven track record of delivering high-quality products on time,” said Duvall, “we believe we offer the best solution at the lowest risk for helping Boeing and the U.S. Air Force extend the power of the B-52 Stratofortress well into the future.”