B-52 Stratofortress Re-Engine
By February 2021 the U.S. Air Force anticipated receiving answers from industry on the B-52 re-engining solicitation in the summer of 2021 but was uncertain on the timing of a downselect decision in the the three-way competition, according to the head of Global Strike Command. For over 60 years, the iconic Stratofortress has been an active symbol of cover and security. Its capabilities have evolved with the mission, from a constant presence in the skies during Cold War-era deterrence, to conventional warfare, to modern-day precision strike, persistence is its profile. This steadfastness shows by the decades of weather on its wings and its unwavering hold in our pride of legacy and determination. And its mission continues. Just as it has adapted to new theaters, munitions, and missions, it must again respond as threats are broader and more varied than ever before. This powerhouse will take on whatever is needed to defend America and deter enemies. To do this going forward requires its first re-engining, a task as critical as the aircraft itself.
The first production B-52A first flew on August 5, 1954, with the first in-service B-52B’s following a short time later. Despite being powered by eight Pratt & Whitney J57 engines, the bomber felt underpowered from the start. Even with waterinjection added for additional thrust at take-off, the aircraft suffered from marginal performance with a full weapons load on a hot day.
In early 1956, Major General Al Boyd, Deputy Commander for Systems, Air Research & Development Command (ARDC), requested the feasibility of replacing the pair of J57’s with a single afterburning J75 engine on each of the outboard pylons to achieve better performance. The prototype XB-52 was made available and the aircraft made a series of flights in this configuration between November 1957 and August 1958, logging over 140 flight hours. Despite the final report stating a ‘substantial performance improvement’, the configuration was not adopted for the fleet. When the last B-52 was delivered to the Air Force on October 26, 1962, this final H-model variant was now utilizing the Pratt & Whitney TF33 turbofan engines which gave much better performance than the original J57s.
Another attempt to find new engines came in 1969 when Boeing began a study to re-engine the B-52 fleet and again in August 1971 when the Air Force and Boeing performed a more detailed study on replacing the engines with High Bypass Ratio Turbofan engines on all B-52G & H models. Boeing studied a concept using a single turbofan on each of the four wing pylons and another that used two engines on a single inboard pylon. During 1975, with the highly-contested Rockwell B-1 program in full swing, members of Congress offered a re-engined and upgraded ‘B-52I’ as a replacement. Again, it was not adopted.
The 1980’s saw Pratt & Whitney making a detailed study into replacing the eight TF33s with four PW2000 (F117) engines. Since it was expected that the B-52 would be replaced by the B-1 and B-2 by the mid-1990’s, this idea never gained traction. The issue was studied again in January 1996 after an incident with B-52H #60 -0054 when a double engine failure caused engines number 3 & 4 to "depart the aircraft" in flight. In this case, Boeing and Rolls-Royce teamed up and proposed the use of the RollsRoyce RB211-535 similar to those used on the commercial 757 aircraft. Although a serious push in the late 1990s and early 2000s, in which the B-52s would get a quartet of General Electric CF6 high-bypass turbofans, was shot down due to a study by the Air Force that concluded spending $4B on new engines for the B-52 fleet would end up saving 'just' $400M, and that is only if the jets flew another 40 years.
In 2004, the USAF independent Science Board study on the subject found that this study was totally inaccurate as it did not factor in tanker gas that costs around 7 to 10 times more than gas loaded on the ground at large US bases. Nor did it take into account the high cost of gas that had to be shipped to exotic locations that are frequented by America's long-range bomber force, such as the island of Diego Garcia. The Science Board's findings are over a decade old now and gas, at times, has over doubled in price over that decade. Had the faulty study not derailed the B-52's re-engining, doing so would have saved massive amounts of money.
By 2003, the cost of overhauling the old TF33 engines had tripled and another USAF/Boeing study on re-engining the fleet determined it would cost approximately $4.5 billion to complete, but would yield a cost savings of nearly $15 billion over the life of the bomber in addition to increasing the combat range by 22% and reducing greenhouse gas emissions. The engine competition between the Pratt & Whitney PW2000, Roll-Royce RB211-535 and CFM International CFM56 (F108) could be partially financed under the Energy Savings Performance Act which allows the Federal Government to partner with private industry on energy conservation methods. Despite the amount of effort put into this proposal, nothing was to become the engineering effort.
Once the Air Force decided that the B-52 would be in service until at least 2040, by which time the service plans to have retired all B-1B and B-2 bombers, a new proposal in 2018 was undertaken to re-engine the 76 plane fleet to fly alongside the nextgeneration Northrop B-21 Raider. This latest effort is known as the Commercial Engine Replacement Program (CERP) with the idea of outfitting the legendary aircraft with commercial off-the-shelf, in-production business jet engines. The goal is 20 to 30 percent better fuel efficiency with a 40 percent increase in range, ease of maintenance utilizing the latest onboard diagnostic equipment and lower greenhouse gas emissions. Pratt & Whitney, Rolls-Royce and General Electric were expected to compete for the multi-year contract to purchase over 600 replacement engines with Boeing serving at the systems integrator.
On 18 May 2020 the Air Force issued formal solicitation for the B-52 Commercial Engine Replacement Program (CERP) engine contract. This acquisition will be an indefinite delivery indefinite quantity contract. The supplies and services provided under this contract will include 608 new, commercial engines (commercial regional/business size jet engines), plus additional spare engines, associated support, spares, support equipment and data to re-engine the B-52 bomber fleet. The Minimum required performance for this contract was the completion of the first year of Program Management. Performance was subject to availability of funds. Initial engine quantities include 16 – 64 engines to integrate onto prototype aircraft, plus additional spares. The remaining quantity of engines will be acquired over the course of multiple ordering periods, for a total contemplated period of performance of up to 17 years. The 17 year period of performance includes a basic period and option periods as follows: one six-year basic period, one five-year option, and six one-year options.
The Air Force initiated development of a B-52 CERP Capabilities Development Document (CDD) to comply with NDAA 2020 direction to establish formal operational requirements for this program. The Air Force developed a B-52 CERP TEMP and began Service coordination August 2020. The program established a B-52 CERP Integrated Test Team to initiate and manage the integrated test planning, execution, and data collection activities outlined in the TEMP. The B-52H Program Office initiated development of a comprehensive, enterprise-level cybersecurity test strategy that will progressively conduct incremental cybersecurity assessments across multiple B-52 modernization programs, including B-52 CERP. This approach was intended to maximize cyber test efficiency while supporting cyber test requirements for multiple B-52 upgrade programs.
On 19 May 2020 a Notice to Offerors tated that : "Funds are not presently available for this effort. No award will be made under this solicitation until funds are available. The Government reserves the right to cancel this solicitation, either before or after the closing date. In the event the Government cancels this solicitation, the Government has no obligation to reimburse an offeror for any costs."
With the B-52 entering its next season of sustainment, GE offered two options to support the U.S. Air Force in its role to maintain U.S. global influence and international order. The lifeline of this aircraft are the engines that power it. The mainstay of America's strategic nuclear fleet demands rugged, reliable, and commercially-proven equipment to continue to operate from a position of enduring strength for the foreseeable future.
The CF34-10 is GE’s most reliable engine even while operating under the harshest conditions — from the highest altitudes in the world to the sweltering heat of the Middle East. Born as a scaled and improved version of the legendary CFM56* engine, the CF34-10 family is a proven stalwart of commercial aviation. Averaging 16,000 cycles to its first overhaul, CF34-10 is projected to stay on wing for the life of the B-52 and beyond — reducing maintenance, manpower, and operating costs. It provides the most thrust in reserve for more missionbased climb in more extreme conditions. It offers the lowest total cost of ownership of any engine offered for the B-52 CERP. Proven fully mature with over 32 million (CF34-10) flight hours and over 174 million CF34 family flight hours. Tackling an average of 8 flights per day with GE’s highest 99.98% dispatch reliability, this engine promises substantial increases in aircraft readiness and availability.
PASSPORT is GE’s most advanced, digitally capable engine built on proven technologies delivering game-changing performance and fuel burn in the most severe environments. Evolved from GE’s most advanced commercial engines - the GEnx used on the Boeing 747 and Boeing 787] and technologies that perform with 99.96% dispatch reliability, it recently powered the longest non-stop business jet flight in history (8,152 nm), a testament to its endurance. This engine offers the lowest fuel burn of any engine in its thrust class enables mission effectiveness: longer mission range, persistence, and increased payload. Dual FADEC (Full Authority Digital Engine Control) offers redundancy for real-time troubleshooting and to guard against mission disruption. Predictive health management provides data analytics to identify and prevent engine-related disruptions. Significant noise and emissions reductions provide environmental, health, and safety benefits for ground personnel and surrounding communities.
Rolls-Royce claimed that the proven BR700 family of business jet engines, with over 25 million flight hours, provides a foundation for the B-52 Re-Engine Program. BR700 series engines, with the US Air Force designation of F130, are already powering both the C-37 and E-11 BACN aircraft. In service around the world, these engines have proven outstanding reliability and efficiency.
Rolls-Royce is the second largest producer of jet engines in the world and already have a large footprint in the US with over $2 billion invested and 6,000 employees. It adds $8.6 billion to the US economy. Rolls-Royce has a long and successful history as a propulsion provider for the US Department of Defense. For the B-52 Re-Engining Program, Rolls-Royce will offer an F130, based on the BR725 business jet engine, and the engine will be produced in the US. The F130 engine based on the BR725 is a good fit for the B-52 with flight proven reliability, superb life cycle cost, and low integration risk. Rolls-Royce is a long-term partner in innovation and have invested over $1 billion in US Research & Development over the last five years. Rolls-Royce Digital Engineering capability has been developed over decades and is ready for the B-52 Re-Engining Program.
The F130 series and Civil fleet have accumulated over 25 million flight hours in operation. Installed in the B-52, this engine will provide vastly greater fuel efficiency while increasing range and reducing tanker requirements. The F130 offers outstanding reliability with high mission readiness and low maintenance demands, ready for integration with the latest Digital Engineering tools. Once installed, the F130 can stay on wing for the planned B-52 lifetime.
Not only would new engines make the B-52 fleet more economical and reliable to operate, they would also extend its already gargantuan range and loitering time, as well as its takeoff performance and its payload lifting abilities. This is something that the airliner industry is well aware of and reworking older designs with new powerplants is a very hot business category for both Boeing and Airbus.
As with any weapons platform it seems, as more money is dumped into it, more money gets dumped into it. An engine upgrade could lead to the B-52 receiving other missions, such as working as a standoff jammer and electronic attack aircraft or working as a long-endurance communications node or radar surveillance and targeting platform.
With new engines and the new economy and capability boost that comes along with them, the B-52 may last far past its current 2040 out of service date. Who knows, it is not out of the realm of possibility that the Big Ugly Fat Fucker could still be plowing the skies well into the second half of the century. Such a feat would be akin to flying a Sopwith Camel into battle today. Another byproduct of an engine swap on the B-52 will be the disappearance of the jet's characteristic long black exhaust trails, which will be a loss for some nostalgic types but a great victory for the environment.
The program will cost $11 billion. Acting Air Force Secretary John P. Roth told lawmakers in June 2021 that this represented a 9 percent jump, he also refuted recent press reports of a 50 percent increase as incorrect. Gen. Timothy M. Ray of Air Force Global Strike Command revealed that depending on the scenario, the new engines would reduce the requirement for aerial refueling by up to 50 percent.
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