The B-52’s new engine, the Rolls Royce F130, has cleared its critical design review, meaning it can enter final development, test, and production on time, the company announced Dec. 13. However, the overall B-52J upgrade, which is integrated by Boeing, continues to run about three years behind.
The review of the F130 “is the culmination of over two years of detailed design work and close collaboration between teams at Rolls-Royce, the Air Force, and Boeing,” according to a Rolls press release.
A Rolls Royce spokesperson said the CDR was conducted over the last few weeks and was for the engine only.
“We are delivering at exactly the pace defined by the Air Force, and conducting the engine CDR on-time is just the latest example of the good work our team is doing,” the spokesperson added.
The overall B-52J upgrade—which includes new radars, new engine pylons, internal wiring, a digital backbone, communications, navigation, other improvements, and overall integration—is years behind schedule, and the Government Accountability Office now projects that initial operational capability, originally expected in 2030, will now come in 2033. A critical design review for the overall effort is expected in August 2025, the GAO said in a June report.
The GAO said the delays stemmed from the Air Force “underestimating the level of funding” necessary to complete detailed design of the re-engining project. There were also delays in sequencing of needed materials and other aspects of the program.
The F130 is based on Rolls’ commercial BR725 powerplant but requires some modification to be compatible with the B-52 and its twin-engine pods. The B-52 will continue to have eight engines in four pods after the overall aircraft upgrade. An earlier version of the F130 engine powers the C-37 and E-11 BACN (Battlefield Airborne Communications Node).
Rolls was picked by the Air Force to provide the engine for the Commercial Engine Replacement Program back in 2021.
On the B-52, the F130 will replace the Pratt & Whitney TF-33, which was original equipment for the B-52H, built in 1962. The engine upgrade will not only provide more power and range for the B-52, but its up-to-date technology will effectively end engine overhauls and drastically reduce maintenance, as will the bomber’s new radars, adapted from equipment on Boeing’s F-15 and F/A-18 fighters. After the upgrade, the B-52J is expected to serve into the 2050s.
“This year we have made strong progress on our F130 testing program,” a Rolls official said, “from completing Rapid Twin Pod Testing to support the B-52’s unique nacelle configuration, to finishing the first phase of sea-level testing for the F130 First Engine to Test (FETT) in Indianapolis.”
Twin-pod tests were also conducted at NASA’s Stennis Space Center in Mississippi.
“Testing at Stennis most notably marked the first time F130 engines were tested in the dual-engine configuration,” the official said. “The testing focused on crosswind aerodynamic flow as well as confirming the successful operation of the engine’s digital controls system. We finished testing at Stennis this summer and collected unprecedented amounts of data to help further de-risk the integration of the F130 engine onto the B-52.”
The next step in preparing the engine for production will be altitude testing at USAF’s Arnold Engineering Development Complex in Tullahoma, Tenn.—set to begin in February 2025.
Rolls will produce the F130 in a purpose-built facility in Indianapolis. It is the company’s largest facility in the U.S., and after pre-production testing, all follow-on testing will be conducted there. Rolls will build more than 600 engines for the B-52 program.