Military

Rolls-Royce to re-engine entire US B-52 bomber fleet

Rolls-Royce to re-engine entir...
The Rolls-Royce F-130 engine will reduce in-air refueling of the B-52
The Rolls-Royce F-130 engine will reduce in-air refueling of the B-52
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The Rolls-Royce F-130 engine will reduce in-air refueling of the B-52
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The Rolls-Royce F-130 engine will reduce in-air refueling of the B-52
The B-52 has been in service since 1955
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The B-52 has been in service since 1955
The F-130 engine
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The F-130 engine
X-ray view of the installed F-130
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X-ray view of the installed F-130
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Rolls-Royce North America has been tapped to supply the replacement jet engines for the venerable Cold War-era B-52 Stratofortress nuclear heavy bomber. Beating out GE Aviation and Pratt & Whitney, the company will provide its F-130 turbofan engine to power the giant aircraft for the next three decades.

The US Air Force's B-52 fleet is now approaching its 70th birthday, which suggests that it should be only found in museums, but the 1950s airframe was so over-engineered and has proven so capable of carrying its 70,000 lb (32,000 kg) of nuclear or conventional weapons across the globe that 76 B-52Hs are still in service, with another 12 held in reserve storage.

However, the B-52s flying today are very different from those that entered service in 1955. Over the years, the aircraft has been extensively modified and upgraded with new electronics, weapon dispensers, and other systems, meaning little is left of the original craft except for the airframe.

X-ray view of the installed F-130
X-ray view of the installed F-130

The latest life extension will involve replacing the current engines with 608 engines (eight per plane) and 42 spares, at a cost of US$2.6 billion under the Commercial Engine Replacement Program (CERP). The engines will be built and tested at Rolls-Royce North America's Indianapolis, Indiana facility. What is unusual is that the F-130 isn't a bespoke engine for the B-52, but a militarized version of the company's BR725 commercial engine that was developed for the Gulfstream G650 business jet.

One advantage of this is that the F-130 already has 27 million engine flight hours under its figurative belt and is already being used in the US Air Force's C-37 executive jet and E-11 Battlefield Airborne Communications Node (BACN) communications aircraft. With 16,900 lb of thrust, the F-130 has a 50-in (130-cm) fan with swept titanium blades, a two-stage turbine, and an HP axial compressor, as well as an improved combustor for significantly lower emissions and greater efficiency. This means that, among other improvements, will be able to B-52 fly longer without in-air refueling.

"We are proud to join a truly iconic U.S. Air Force program and provide world-class, American-made engines that will power its missions for the next 30 years," says Tom Bell, Chairman & CEO, Rolls-Royce North America, and President – Defense. "The F130 is a proven, efficient, modern engine that is the perfect fit for the B-52."

Source: Rolls-Royce

View gallery - 4 images
9 comments
9 comments
Chase
It's a little odd to me that they would go with a new engine that has slightly less thrust than the outgoing engine that they started installing in the B-52H. The efficiency and ubiquity must have been good selling points. Would've been interesting to see how the efficiency of the two engines compares, even if it had to be comparing the civilian variants of the two engines.
windykites
I remember seeing the trail of black smoke when the B52 takes off, indicating inefficiency.
I thought they might replace the 8 engines with 4 High bypass engines.
Food4Thought
@windykites - At one point they did consider replacing 8 engines with just 4 high bypass fan engines...but apparently they would need to remodel the airflow around the engine nacelle (single engine vs. 2), as it would impact flying characteristics, and also airflow interaction with external weapons pylons. So - instead of all of that bother, they just decided to replace engine for engine, or so I had once read.
DavidIngram
Re-engine? Definitely, but this solution will get questioned an challenged.
mediabeing
Well, good for Rolls Royce...but they'd better be built here in the states.
Royce was an early powered flight death.
mediabeing
My mistake - It was Charles Rolls who 'bought the farm' by way of Britain's first powered flight fatality.
Gregg Eshelman
@windykites The black smoke trails were from oil. The engines the B-52 used before the TF-33 didn't have bearing seals capable of holding the oil pressure so under high thrust operation, which came with increased temperatures, oil would blow out of the bearings due to higher pressure used to keep the bearings cool.

The early F-4 Phantom fighters also used engines like that. When I was a kid in the 1970's there were regular flights of Phantoms from Gowen Field that went near my house and I remember seeing the black smoke trails when they had the throttles wide open.

When the engines on such planes got upgraded to models that had much better seals, they no longer needed large oil tanks to make up for the loss out the exhaust. Fixing that was also a benefit to defense because it was much harder for people on the ground to aim surface to air missiles when they didn't have a big sooty trail pointing right at the planes.

Earlier jet engines ran a total loss oiling system. The planes needed extra large oil tanks because all the oil that went to the engine bearings went out the exhaust. That played a role in the B-52 being the bomber still flying instead of the B-49. The day before an important demonstration flight of a YB-49 prototype, its fuel and oil tanks were filled. Being a prototype, it didn't have level gauges for the oil tanks. Nor did the crew check the tanks because they'd filled them the previous day. But during the flight then engines all ran out of oil, the bearings seized up and it crashed.

The B-52 won the contract because of sabotage. Someone had to have drained most of the oil from the tanks but AFAIK there never was any investigation because the government people in charge of selecting the new bomber had never once really considered the B-49 because they simply thought a flying wing was too unconventional. So somebody, to ensure the YB-49 wouldn't get the win on performance and other points, made sure it wouldn't.
AkBuilder
From a B-52 crew member. The TF-33 and J-57 engines both had a two-stage turbine, and a high pressure axial flow compressor so nothing new there. The black smoke that used to stream from the J-57 engines on takeoff (B-52 & early KC-135) was the result of the water injection to boost thrust on takeoff. The water injection lasted just about two minutes and was noticeable as the aircraft always had a sudden little yaw when it happened. When the water ran out, the black smoke stopped.
Sean O'Callaghan
An American airframe and British engine. There is some pedigree there - what’s not to like?