The Pentagon has announced that the US Air Force has selected the US subsidiary of the British Rolls-Royce Group to supply new turbofan engines for the remaining fleet of 76 B-52H Stratofortress bombers. This upgrade program has been under discussion for years and should now enable these decades-old bombers to be used until 2050.
According to information included on September 24 in the Pentagon’s daily contract notices (which contain information on all awards worth almost seven billion euros), the contract provides for 608 commercial engines of the BR700 series (military version BR725 or F130) known from large business jets plus spare engines, associated support equipment and commercial technical data to be used for the B-52H bomber fleet, including maintenance activities. The volume is estimated at around 430 million euros over the next six years, but will grow to more than 2.2 billion euros if all options are exercised. The contract will be performed in Indianapolis, Indiana, and the work is expected to be completed by September 2038. This is to be followed by a “substantial” period of service. https://www.youtube.com/watch?v=2sHUJnsMC2M
It remains eight engines …
The total number of engines mentioned is exactly enough for the one-for-one replacement of the eight thirsty but weaker Pratt & Whitney TF33 turbojet engines, notorious for their exhaust emissions, found in four twin nacelles on each of the USAF’s 76 B-52H bombers. To keep costs down, the companies competing for the upgrade deal (General Electric’s CF34-10 and Pratt & Whitney’s PW800) were invited to submit proposals that would be able to utilize the four twin nacelles. A conversion last considered in 2017 with four large single turbofan engines as on airliners would have entailed aerodynamic changes, subtance changes to the wing, pylons and fuel system and was therefore rejected. Rolls-Royce-US is confident that the F130s will not need to be fully replaced during the remaining expected service life of the Air Force’s B-52Hs, but has made provision for the USAF to receive spares and additional engines if it determines it needs them. https://militaeraktuell.at/rising-from-the-desert-alte-b-52-hebt-wieder-ab/ ... but much more efficiency
In its own reports from 2016, for example, the USAF spent around €1.7 million per engine to overhaul the TF33 every 6,000 flight hours. This was a key driver behind the Air Force’s decision to push ahead with this service life extension again in 2017. The F130 delivers 160 kN instead of the TF33’s 80 kN, but offers significantly higher fuel efficiency and therefore increases range and dwell time, thus considerably reducing the requirements for tanker aircraft. From an environmental point of view, the characteristic four smoke plumes have been eliminated and noise levels massively reduced. And the engine family is already familiar to the USAF, flying in the C-37A and -B (military designations for the Gulfstream-V and -550) and the Bombardier E-11A Battlefield Airborne Communications Node (BACN). This is expected to further simplify the maintenance and logistics chains.
100 years in service?
If the program now initiated is fully exploited, the B-52H could become the first military aircraft in the world to reach 100 years of service as a veteran of the Cold War. The first flight of the first B-52 prototype took place on April 15, 1952.
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