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86-670: The Northrop Grumman B-21 Raider is an American strategic bomber in development for the United States Air Force (USAF) by Northrop Grumman . Part of the Long Range Strike Bomber (LRS-B) program, it is to be a stealth intercontinental strategic bomber that can deliver conventional and thermonuclear weapons . Named "Raider" in honor of the Doolittle Raiders of World War II , the B-21

172-688: A stealth intercontinental strategic bomber for the USAF, able to deliver conventional and thermonuclear weapons . The Air Force issued a request for proposal to develop an LRS-B aircraft in July 2014. A development contract was awarded to Northrop Grumman in October 2015. Boeing and Lockheed Martin , who submitted losing bids for the project, filed bid protests; in October 2016, the Government Accountability Office (GAO) rejected

258-695: A 1986 DARPA project under the auspices of the Advanced STOVL (ASTOVL) program, an early progenitor of the Joint Strike Fighter (JSF) that resulted in the F-35. Lockheed engineer Paul Bevilaqua developed and eventually patented a concept aircraft and a propulsion system called the Shaft-Driven Lift Fan (SDLF), and then turned to Pratt & Whitney (P&W) to build a demonstrator engine. The ground test demonstrator used

344-511: A 5–7% lower fuel burn. The plans include better cooling technology for turbine blades; this would increase the longevity of the engine and substantially reduce maintenance costs. The goal of Block 2 is to work with the US Air Force's Adaptive Engine Transition Program , with the intention of introducing technology for an engine rated at 45,000 lb of thrust, to be used in a sixth-generation fighter. Pratt & Whitney's upgrade path for

430-676: A clutch in STOVL mode. Finally, a variable thrust deflecting nozzle was added to complete the "F100-229- Plus " demonstrator engine. This ground demonstrator engine proved the shaft-driven lift fan concept and led to the development of the eventual JSF engine. ASTOVL continued under the Common Affordable Lightweight Fighter (CALF) program in 1993 before eventually being merged into the Joint Advanced Strike Technology (JAST), which

516-467: A larger diameter one. When the F135 is providing vertical lift using the increased bypass ratio from the lift fan, the thrust augmentation is 50% with no increase in fuel flow. Thrust augmentation is 52% in conventional flight when using the afterburner, but with a large increase in fuel flow. The transfer of approximately 1 ⁄ 3 of the power available for hot nozzle thrust to the lift fan reduces

602-539: A modern strategic bombing mission need not always necessarily be a heavy bomber type, and any modern aircraft capable of nuclear strikes at long range is equally able to carry out tactical missions with conventional weapons . An example is France 's Mirage IV , a small strategic bomber replaced in service by the ASMP -equipped Mirage 2000N fighter-bomber and Rafale multirole fighter . The first strategic bombing efforts took place during World War I (1914–18), by

688-421: A more durable version of the F135 engine to increase the service life of key parts. The life expectancy of the parts was reduced because the hot sections of the engine (combustor and high-pressure turbine blades specifically) ran hotter than expected. The test engine is designated XTE68/LF1 , and testing is expected to begin in 2010. This redesign has caused "substantial cost growth". P&W expected to deliver

774-560: A powerplant selection and particular powerplant installation design features on the 30-meter wingspan Greif , that led to endless problems with engine fires. The trans-Atlantic ranged Amerika Bomber program started in March 1942 sought to ameliorate the lack of a long-range bomber for the Luftwaffe , but led only to three Messerschmitt - and two Junkers -built prototypes ever flying, and no operational "heavy bombers" for strategic use for

860-413: A solid part adding 6 lb (2.7 kg) in weight. In 2013, a former P&W employee was caught attempting to ship "numerous boxes" of sensitive information about the F135 to Iran. Despite the troubles, the 100th engine was delivered in 2013. LRIP-6 was agreed in 2013 for $ 1.1 billion for 38 engines of various types, which helped to decrease the unit cost. Air Force Lt. Gen. Christopher C. Bogdan,

946-640: A version of Tupolev Tu-16 on license from the Soviet Union in the 1960s, which they named the Xian H-6 . During the 1960s France produced its Dassault Mirage IV nuclear-armed bomber for the French Air Force as a part of its independent nuclear strike force, the Force de Frappe , using French-made bombers and IRBMs to deliver French-made nuclear weapons . Mirage IVs served until mid-1996 in

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1032-416: Is a crucial platform in a potential fight against China. In March 2022, Air Force Secretary Frank Kendall III raised the possibility of a bomber drone to work with the bomber, but the idea was later dropped because it would not save much money to produce such a large unmanned aircraft. The USAF is also planning to acquire a new long-range fighter from its Next Generation Air Dominance program, known as

1118-399: Is a major objective for the F135. The engine has fewer parts than similar engines, which improves reliability. All line-replaceable components (LRCs) can be removed and replaced with a set of six common hand tools. The F135's health management system is designed to provide real time data to maintainers on the ground. This allows them to troubleshoot problems and prepare replacement parts before

1204-434: Is a primary driver for the increased potential problem notifications." A&P Alloys stated that they stood behind their product even though they were not given access to the parts to do their own testing. Tracy Miner, an attorney with Boston-based Demeo LLP representing A&P Alloys said, "it is blatantly unfair to destroy A&P’s business without allowing A&P access to the materials in question" In July 2014 there

1290-605: Is an afterburning turbofan developed for the Lockheed Martin F-35 Lightning II , a single-engine strike fighter. It has two variants; a Conventional Take-Off and Landing ( CTOL ) variant used in the F-35A and F-35C, and a two-cycle Short Take-Off Vertical Landing ( STOVL ) variant used in the F-35B that includes a forward lift fan . The first production engines were delivered in 2009. Developed from

1376-424: Is expected to operate from bases that currently host heavy bombers, such as Dyess Air Force Base , Texas; Ellsworth Air Force Base , South Dakota; and Whiteman Air Force Base , Missouri. In March 2019, Ellsworth was selected as the base to host the first operational B-21 unit, as well as the first training unit. The B-21 is slated to, by 2040, replace the U.S. Air Force's 45 B-1 strategic bombers, which date from

1462-639: Is meant to replace the Rockwell B-1 Lancer and Northrop Grumman B-2 Spirit by 2040, and possibly the Boeing B-52 Stratofortress after that. The Air Force began planning for the B-21 in 2011 and awarded the major development contract in 2015, aiming to have it in service "in the mid-2020s". By 2021, that date had slipped to 2027. As of 2021, many aspects of the B-21 special access program were still highly classified , though some information about various other aspects of

1548-546: Is obtained from a two-stage lift fan (about 46% ) in front of the engine, a vectoring exhaust nozzle (about 46% ), and a nozzle in each wing using fan air from the bypass duct (about 8% ). These contributions to the total lift are based on thrust values of 18,680 lbf (83.1 kN), 18,680 lbf (83.1 kN) and 3,290 lbf (14.6 kN) respectively. Another source gives thrust values of 20,000 lbf (89 kN), 18,000 lbf (80 kN), and 3,900 lbf (17 kN) respectively. In this configuration most of

1634-591: Is responsible for the electronic engine control system, actuation system, PMAG, gearbox, and health monitoring systems. Woodward, Inc. is responsible for the fuel system. The F135 is assembled at a plant in Middletown, Connecticut . Some parts of the engine are made in Longueuil , Quebec, Canada, and in Poland. The first production propulsion system for operational service was scheduled for delivery in 2007 with

1720-483: The 2003 invasion of Iraq , American B-52s and B-1s were mostly employed in tactical roles. During the Soviet-Afghan war in 1979–88, Soviet Air Forces Tu-22Ms carried out several mass air raids in various regions of Afghanistan . Bombers listed below were used in the main or represented a shift in long-range bomber design (Maximum bomb load). In practice, bomb loads carried are dependent on factors such as

1806-653: The B-52 last manufactured in 1962 and the Tupolev Tu-95 , remain in service and can also deploy the latest air-launched cruise missiles and other " stand-off " or precision guided weapons such as the JASSM and the JDAM . The Russian Air Force 's new Tu-160M2 strategic bombers are expected to be delivered on a regular basis over the course of 10 to 20 years . The Tu-95 and Tu-160 bombers will be periodically updated, as

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1892-708: The Cold War began, it became an intercontinental range strategic bomber with the development of new techniques, such as aerial refueling (which also greatly extended the range of other medium- to long-range bombers , fighter-bombers and attack aircraft ). During the 1950s the U.S. Strategic Air Command also briefly brought back the outdated term " medium bomber " to distinguish its Boeing B-47 Stratojets from somewhat larger contemporary Boeing B-52 Stratofortress " heavy bombers " in bombardment wings; older B-29 and B-50 heavy bombers were also redesignated as "medium" during this period. SAC 's nomenclature here

1978-531: The Cold War , the United States and United Kingdom on one side and the Soviet Union on the other kept strategic bombers ready to take off on short notice as part of the deterrent strategy of mutually assured destruction (MAD). Most strategic bombers of the two superpowers were designed to deliver nuclear weapons . For a time, some squadrons of Boeing B-52 Stratofortress bombers were kept in

2064-717: The Dassault Mirage 2000N and Rafale fighter-bombers ; the Rafale is also capable of refueling others in flight using a buddy refueling pod . Newer strategic bombers such as the Rockwell B-1 Lancer , the Tupolev Tu-160 , and the Northrop Grumman B-2 Spirit designs incorporate various levels of stealth technology in an effort to avoid detection, especially by radar networks. Despite these advances earlier strategic bombers, for example

2150-454: The House of Commons early in the 1930s that " the bomber will always get through " no matter what defensive systems were undertaken. It was widely believed by the late 1930s that strategic "terror" bombing of cities in any war would quickly result in devastating losses and might decide a conflict in a matter of days or weeks. But theory far exceeded what most air forces could actually put into

2236-700: The Junkers Ju 88 A. Support for the Ural bomber project before the start of WW II dwindled after Wever's death, with the only aircraft design that could closely match the Allied bomber force's aircraft – the Heinkel He 177 A, originated in early November 1937, deployed in its initial form in 1941–42, hampered by a RLM requirement for it to also perform medium-angle dive bombing , not rescinded until September 1942 – unable to perform either function properly, with

2322-618: The Pratt & Whitney F119 engine used on the F-22 Raptor , the F135 produces around 28,000 lbf (125 kN) of thrust and 43,000 lbf (191 kN) with afterburner. The F135 competed with the General Electric/Rolls-Royce F136 to power the F-35. The F135 originated with Lockheed Corporation Skunk Works , with efforts to develop a stealthy STOVL strike fighter for the U.S. Marine Corps under

2408-597: The Russians with their Sikorsky Ilya Muromets bomber (the first heavy four-engine aircraft), and by the Germans using Zeppelins or long-range multi-engine Gotha aircraft . Zeppelins reached England on bombing raids by 1916, forcing the British to create extensive defense systems including some of the first anti-aircraft guns which were often used with searchlights to highlight the enemy machines overhead. Late in

2494-519: The nuclear strike role, France would replace its Mirage IVs beginning in the late 1980s with the even smaller, single-engine Mirage 2000N fighter-bomber , a further example of advancing technologies and changing tactics in military aviation and aircraft design . France's newer twin-engine Dassault Rafale multirole fighter also has nuclear strike capability. Weapons loads can include nuclear -armed missiles as well as aerial bombs Pratt %26 Whitney F135 The Pratt & Whitney F135

2580-511: The -100 and the -600 versions. A -400 version is mentioned, similar to the -100, the main difference being the use of salt-corrosion resistant materials. The -600 is described below with an explanation of the engine configuration changes that take place for hovering. The engine and Rolls-Royce LiftSystem make up the Integrated Lift Fan Propulsion System (ILFPS). The vertical thrust for the STOVL version

2666-464: The 1980s, and 19 B-2 strategic bombers, which date from the 1990s. The B-21 may also eventually replace the B-52, which originally dates from the 1950s and is slated to remain in service for many decades. The USAF plans to replace its bomber fleet and most of the service’s nuclear delivery weapons, including its ICBMs. The Air Force is focusing on Indo-Pacific operations around the B-21, which officials say

Northrop Grumman B-21 Raider - Misplaced Pages Continue

2752-463: The B-21 as "the world's first sixth-generation aircraft." At the 2016 Air Warfare Symposium, Air Force officials announced that the LRS-B would be designated "B-21" because it would be the 21st century's first bomber. In September 2016, Air Force officials announced that the B-21 would be named "Raider" in honor of the Doolittle Raiders . Retired Lt. Col. Richard E. Cole , then the last living member of

2838-519: The B-21 flew its second publicly acknowledged test flight from Edwards AFB. By September 2024, three test aircraft were in service: one performing one or two flight tests per week, and the others involved in ground tests. Data from Aviation Week & Space Technology General characteristics Performance Related development Aircraft of comparable role, configuration, and era Related lists Strategic bomber The modern strategic bomber role appeared after strategic bombing

2924-468: The B-21 program by $ 302 million "due to a lower than expected contract award value", while requiring "strict   ...program baseline and cost control thresholds", "quarterly program performance reports", and "disclosure of the engineering and manufacturing development total contract award value". The versions of the 2017 NDAA as initially passed by the House and Senate would have required public disclosure of

3010-658: The B-21 program remains subject to the Nunn–McCurdy reporting requirements to Congress. A 2015 media report said the Air Force wanted the bomber to also function as an intelligence collection platform , battle manager , and interceptor aircraft . In 2016, then–Secretary of the Air Force Deborah Lee James said that the B-21 would be a "fifth-generation global precision attack platform" with networked sensor-shoot capability. Northrop Grumman describes

3096-802: The Defence Strategic Review released by the Australian government on 24 April 2023 stated that the B-21 was not considered a suitable option for acquisition. Australia will instead invest in the upgrading of its F-35As and F/A-18Fs to the latest Block 4 and Block III configurations, respectively, to enable both aircraft to be capable of launching the AGM-158C LRASM and the Joint Strike Missile . As part of an Institute of Public Affairs paper released in August 2024,

3182-606: The Doolittle Raiders, was present at the naming ceremony at the Air Force Association conference. In March 2016, the USAF announced seven tier-one suppliers for the program: Pratt & Whitney , BAE Systems , Spirit AeroSystems , Orbital ATK , Rockwell Collins , GKN Aerospace , and Janicki Industries. In 2016, the F-35 program manager Chris Bogdan said the B-21's engines would be similar enough to

3268-419: The F-35 flight envelope while also getting a 5–6% fuel burn reduction. In June 2018, United Technologies , parent company of P&W, announced Growth Option 2.0 to help provide increased power and thermal management system (PTMS) capacity, providing options for operators for instance if they are wishing to upgrade to heavier weapons. Although Growth Option 2.0 was initially envisaged as a further development of

3354-644: The F-35's Pratt & Whitney F135 engine to reduce its cost. The program completed its critical design review in December 2018. In January 2020, Air Force officials released new B-21 renderings, showing the distinctive flush and blended inlets and the two-wheel main landing gear design. The drawing appeared to show a smaller, lighter aircraft than the B-2. In February 2016, the head of the Air Force Global Strike Command said he expected

3440-524: The F-X or "Penetrating Counter-Air", to escort the B-21 deep into enemy territory and help it survive enemy air defenses and intercepting fighters. In December 2022, an Australian Strategic Policy Institute report advocated the acquisition of a number of B-21 Raiders to enable Australia to have a greater long-range strike capability. The report states that a B-21 could fly 2,500 miles (4,000 km) without refueling while carrying more munitions as compared to

3526-507: The F135 below the cost of the F119, even though it was a more powerful engine. However, in February 2013 a cracked turbine blade was found during a scheduled inspection. The crack was caused by operating at high turbine temperatures for longer periods than usual. In December 2013 the hollow first stage fan blisk failed at 77% of its expected life during a ground test. It was to be replaced by

Northrop Grumman B-21 Raider - Misplaced Pages Continue

3612-655: The F135 with an adaptive fan to become the XA101 , a three-stream adaptive cycle engine , Pratt & Whitney has since split the XA101 as an entirely separate design with a new core, while Growth Option 1.0 would evolve to become the F135 Engine Enhancement Package (EEP), later renamed Engine Core Upgrade (ECU). In 2023, the USAF chose to fund the ECU for further development and fielding by 2029 to support

3698-588: The F135 would change several times, with Block 1 and 2 initially becoming Growth Option 1 and 2. At the end of May 2017 Pratt and Whitney announced the F135 Growth Option 1 had finished testing and was available for production. The upgrade requires the changing of the power module on older engines during depot overhaul and can be seamlessly inserted into future production engines at a minimal increase in unit cost and no impact to delivery schedule. The Growth Option 1 offers an improvement of 6–10% thrust across

3784-448: The LP rotor and a clutch. The engine operates as a separate flow turbofan with a higher bypass ratio. The power to drive the fan—about 30,000 shp (22,000 kW) —is obtained from the LP turbine by increasing the hot nozzle area. A higher bypass ratio increases the thrust for the same engine power as a fundamental consequence of transferring power from a small diameter propelling jet to

3870-865: The Soviet Union or its allies, two V bomber types, the Avro Vulcan and the Handley Page Victor , were used in the Falklands War towards the end of their operational lives. The Soviet Union produced hundreds of unlicensed copies of the American Boeing B-29 Superfortress , which the Soviet Air Forces called the Tupolev Tu-4 . The Soviets later developed the jet -powered Tupolev Tu-16 "Badger". The People's Republic of China produced

3956-673: The Third Reich beyond the roughly one thousand He 177s built. By the end of the Second World War in 1945, the "heavy" bomber, epitomized by the British Avro Lancaster and American Boeing B-29 Superfortress used in the Pacific Theater , showed what could be accomplished by area bombing of Japan's cities and the often small and dispersed factories within them. Under Major General Curtis LeMay ,

4042-527: The U.S. 20th Air Force , based in the Mariana Islands , undertook low-level incendiary bombing missions, results of which were soon measured in the number of square miles destroyed. The air raids on Japan had withered the nation's ability to continue fighting, although the Japanese government delayed surrender until atomic bombs were dropped on Hiroshima and Nagasaki in August 1945. During

4128-458: The US might allow Australia to procure the B-21. When asked if the US would consider allowing Australia to join in developing the B-21 bomber, Air Force Secretary Frank Kendall stated, "I don't think that there's any fundamental limitation on the areas in which we can cooperate. If Australia had a requirement for long-range strike, then we'd be willing to have a conversation with them about that." However,

4214-515: The YF119-611 would form the basis for the F135, which integrates the F119 core with new components optimized for the JSF. The F135 team is made up of Pratt & Whitney , Rolls-Royce and Hamilton Sundstrand . Pratt & Whitney is the prime contractor for the main engine, and systems integration. Rolls-Royce is responsible for the vertical lift system for the STOVL aircraft. Hamilton Sundstrand

4300-471: The ability to export components to foreign buyers. Warden said that the B-21's internal operations were "extremely advanced compared to the B-2" and that the B-21 was slightly smaller than the B-2, with a longer range . The first B-21s are not prototypes but rather test aircraft that the Air Force will convert to operational configuration after the completion of tests. In September 2023, program officials said fueling and engine tests were proceeding ahead of

4386-642: The air around the clock, orbiting some distance away from their fail-safe points near the Soviet border. The British produced three different " V bombers " for the Royal Air Force which were designed and designated to be able to deliver British-made nuclear bombs to targets in European Russia. These bombers would have been able to reach and destroy cities such as Kiev or Moscow before American strategic bombers. While they were never used against

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4472-425: The air. Germany focused on short-range tactical bombers. Britain 's Royal Air Force began developing four-engine long-range bombers only in the late 1930s. The U.S. Army Air Corps ( Army Air Forces as of mid-1941) was severely limited by small budgets in the late 1930s, and only barely saved the B-17 bomber that would soon be vital. The equally important B-24 first flew in 1939. Both aircraft would constitute

4558-405: The aircraft returns to base. According to Pratt & Whitney, this data may help drastically reduce troubleshooting and replacement time, as much as 94% over legacy engines. Prior to any services issuing a requirement for an upgraded engine, Pratt and Whitney had cooperated with the US Navy on a two-block improvement plan for the F135 engine. The goals of Block 1 are a 7–10% increase in thrust and

4644-409: The anticipated first flight by year's end. The first test flight of the B-21 took place on 10 November 2023 at the Air Force's Plant 42 in Palmdale, California. On 23 January 2024, a low rate initial production (LRIP) contract was awarded. In July 2016, the USAF said it would not release the estimated cost of Northrop's B-21 contract, asserting that the number would reveal too much information about

4730-415: The bomber role, and to 2005 as reconnaissance aircraft . The French Republic limited its strategic armaments to a squadron of four nuclear-powered ballistic missile submarines , with 16 SLBM tubes apiece. France also maintains an active force of supersonic fighter-bombers carrying ASMP stand-off nuclear missiles , with Mach 3 speed and a range of 500 kilometers. These missiles can be delivered by

4816-490: The bulk of the bomber force for USAAF strategic bombing in Europe and Allied day bomber units more generally. At the start of World War II , so-called "strategic" bombing was initially carried out by medium bomber aircraft which were typically twin-engined, armed with several defensive guns, but only possessed limited bomb -carrying capacity and range . Both Britain and the US were developing larger two- and four-engined designs, which began to replace or supplement

4902-410: The bypass flow is ducted to the wing nozzles, known as roll posts. Some is used for cooling the rear exhaust nozzle, known as the 3-bearing swivel duct nozzle (3BSD). At the same time an auxiliary inlet is opened on top of the aircraft to provide additional air to the engine with low distortion during the hover. The low pressure (LP) turbine drives the lift fan through a shaft extension on the front of

4988-411: The challenges and sustained the USAF's decision to award the LRS-B contract to Northrop Grumman. The GAO report revealed that cost was the deciding factor in selecting Northrop Grumman over the Boeing-Lockheed Martin team. Management and acquisition of the B-21 program is being overseen by the Air Force Rapid Capabilities Office , rather than through the traditional military-procurement process. However,

5074-448: The classified project to potential adversaries. The Senate Armed Services Committee also voted to not publicly release the program's cost, restricting the information to congressional defense committees over the objections of a bipartisan group of legislators led by the committee's chairman, Senator John McCain . McCain's proposed revisions to the National Defense Authorization Act for Fiscal Year 2017 would have reduced authorization for

5160-467: The distance to target and the individual type, size or weight of bombs used. Nomenclature for size classification of aircraft types used in strategic bombing varies, particularly since the time of World War II due to sequential technological advancements and changes in aerial warfare strategy and tactics. The B-29 , for example was a benchmark aircraft of the heavy bomber type at end of World War II due to its size, range and load carrying ability; as

5246-410: The executive officer of the F-35 program, has called out P&W for falling short on manufacturing quality of the engines and slow deliveries. His deputy director Rear Admiral Randy Mahr said that P&W stopped their cost-cutting efforts after "they got the monopoly". In 2013 the price of the F135 increased by $ 4.3 billion. In May 2014, Pratt & Whitney discovered conflicting documentation about

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5332-399: The first B-21 approached, construction on the second unit had begun. At a congressional hearing in June 2021, Darlene Costello, the acting Assistant Secretary of the Air Force Acquisition, Technology & Logistics , confirmed that the first two B-21s were under construction at Plant 42. By February 2022, six B-21s were under construction. The first B-21 was moved to a calibration facility

5418-468: The first of six recommendations encourages the Australian Government to reconsider their position on the Raider, and stating that they should purchase it to reconcile a long-range strike gap should the AUKUS program have delays. The test program is managed by the Air Force Test Center and the 412th Test Wing 's B-21 Combined Test Force, which includes Northrop Grumman personnel. The first B-21 made its maiden flight on 10 November 2023. On 17 January 2024,

5504-434: The first stage fan from a F119 engine for the lift fan. The engine fan and core from the F100-PW-220 were used for the core of the demonstrator engine, and the larger low-pressure turbine from the F100-PW-229 was used for the low-pressure turbine of the demonstrator engine. The larger turbine was used to provide the additional power required to operate the lift fan through the low-pressure spool shaft, which would be engaged by

5590-432: The following month. About 8,000 Northrop Grumman employees had worked on the program with more than 400 suppliers from at least 40 states. The first B-21 test aircraft was unveiled at Northrop Grumman's production facilities in Palmdale, California, on 2 December 2022. At the unveiling, Northrop CEO Kathy Warden said that the B-21 is designed with modular, open systems architecture to allow easy upgrades and, potentially,

5676-403: The material limit of 540 °C (1,000 °F). Micro cracks appeared in third-stage fan blades, according to program manager Christopher Bogdan, causing blades to separate from the disk. The failed blades punctured a fuel tank and hot air mixing with fuel caused the fire. As a short term fix, each aircraft is flown on a specific flight profile to allow the rotor seal to wear a mating groove in

5762-402: The maximum 930 miles (1,500 km) range of the RAAF's F-35 fighter jets, which require air-to-air refueling. A single B-21 can also deliver the same impact as several F-35As. Additionally, the B-21 can attack targets from secure air bases located in Australia's south, with greater proximity to more personnel, fuel, and munitions. During bilateral talks held in August 2022, it was reported that

5848-434: The origin of titanium material used in some of its engines, including the F135. The company assessed that the uncertainty did not pose a risk to safety of flight but suspended engine deliveries as a result. Bogdan supported P&W's actions and said the problem was now with A&P Alloys, the supplier. The US Defense Contract Management Agency wrote in June 2014 that Pratt & Whitney's "continued poor management of suppliers

5934-402: The program have been made public since 2015. The first B-21 aircraft was unveiled at a 2 December 2022 ceremony at Northrop Grumman's production facilities in Palmdale, California . The first flight of a B-21 occurred on 10 November 2023. By September 2024, three airworthy B-21s were involved in program testing. The classified Long Range Strike Bomber (LRS-B) program began in 2011, to create

6020-503: The purpose of serving the U.S., UK, and other international customers. The initial F-35s went into production with the F135 engines, but the GE / Rolls-Royce team planned to develop a replacement F136 engine in July 2009. In 2010, the Pentagon planned for the two propulsion systems to be competitively tendered. However, since 2006 the Defense Department has not requested funding for the alternate F136 engine program, but Congress has maintained program funding. As of 2009, P&W developed

6106-453: The service would place an initial order for 100 B-21s and build up to a full fleet of 175 to 200. In 2017, two USAF studies suggested that Air Force could increase its initial purchase from 80-to-100 to 145 aircraft. Assembly of the B-21 takes place at the United States Air Force Plant 42 near Palmdale, California , at the same facility Northrop Grumman used during the 1980s and 1990s to build B-2 bombers. In January 2017, Northrop Grumman

6192-429: The smaller aircraft by 1941–42. After American entry into the war in December 1941, the U.S. 8th Air Force began to develop a daylight bombing capacity using improved B-17 and B-24 four-engine aircraft. In order to assemble the formations to carry out these bombing campaigns, assembly ships were used to quickly form defensive combat boxes . The RAF concentrated its efforts on night bombing . But neither force

6278-478: The stator to prevent excessive rubbing. Pratt & Whitney managed to meet their 2015 production goals, but "recurring manufacturing quality issues" in turbine blades and electronic control systems required engines to be pulled from the fleet. Derived from the F119 engine, the F135 is a mixed-flow afterburning turbofan utilizing a similar core as the F119 with a new fan and LP turbine. There are two F135 variants:

6364-485: The temperature and velocity of the rear lift jet impinging on the ground. The F-35 can achieve a limited 100% throttle cruise without afterburners of Mach 1.2 for 150 miles (240 km; 130 nmi). Like the F119, the F135 has a stealthy augmentor where traditional spray bars and flameholders are replaced by thick curved vanes coated with ceramic radar-absorbent materials (RAM). Afterburner fuel injectors are integrated into these vanes, which block line-of-sight of

6450-538: The total cost of the B-21, but this provision was removed in the final conference report version. In December 2022, the cost of the B-21 was estimated at $ 700 million per aircraft. At the time, Air Force officials estimated that they would spend at least $ 203 billion over 30 years to develop, purchase, and operate a fleet of at least 100 B-21s. Maintenance and sustainment of the B-21 will be coordinated by Tinker Air Force Base , Oklahoma, while Edwards Air Force Base , California, will lead testing and evaluation. The B-21

6536-552: The turbines, contributing to aft-sector stealth. The axisymmetric nozzle consists of fifteen partially overlapping flaps that create a sawtooth pattern at the trailing edge. This creates shed vortices and reduces the infrared signature of the exhaust plume. The effectiveness is reportedly comparable to that of the F119's wedge nozzles, while being substantially more cost effective and lower maintenance. The engine uses thermoelectric -powered sensors to monitor turbine bearing health. Improving engine reliability and ease of maintenance

6622-479: The untimely death of the top German advocate for strategic bombing, General Walther Wever in early June 1936, the focus of Nazi Germany's Luftwaffe bomber forces, the so-named Kampfgeschwader (bomber wings) became the battlefield support of the German Army as part of the general Blitzkrieg form of warfare, carried out with both medium bombers such as the Heinkel He 111 , and Schnellbombers such as

6708-521: The war, American fliers under the command of Brig. Gen. Billy Mitchell were developing multi-aircraft "mass" bombing missions behind German lines, although the Armistice ended full realization of what was being planned. Study of strategic bombing continued in the interwar years. Many books and articles predicted a fearful prospect for any future war, paced by political fears such as those expressed by British Prime Minister Stanley Baldwin who told

6794-537: Was able to develop adequate bombsights or tactics to allow for often-bragged "pinpoint" accuracy. The post-war U.S. Strategic Bombing Survey studies supported the overall notion of strategic bombing, but underlined many of its shortcomings as well. Attempts to create pioneering examples of " smart bombs " resulted in the Azon ordnance, deployed in the European Theater and CBI Theater from B-24s. Following

6880-450: Was an uncontained failure of a fan rotor while the aircraft was preparing for take-off. The parts passed through a fuel tank and caused a fire, grounding the F-35 fleet. During high g-force maneuvering three weeks before the flight, flexing of the engine caused excessive rubbing at the seal between the fan blisk and the fan stator initiating the impending failure. The rub caused a temperature of over 1,000 °C (1,900 °F), well beyond

6966-410: Was awarded a $ 35.8 million contract modification for a large coatings facility at Plant 42, to be completed by the end of 2019. The contract announcement did not specifically mention B-21, but the facility was likely meant for B-21 stealth coating. By the summer of 2019, it was reported that construction of the first aircraft was underway. In early 2021, several media outlets reported that as completion of

7052-693: Was done during the 1990s with the Tu-22M bombers. Strategic bombers of the Cold War were primarily armed with nuclear weapons. During the post-1940s Indochina Wars , and also since the end of the Cold War, modern bombers originally intended for strategic use have been exclusively employed using non-nuclear , high explosive weapons. During the Vietnam War , Operation Menu , Operation Freedom Deal , Gulf War , military action in Afghanistan , and

7138-697: Was purely semantic and bureaucratic, however as both the B-47 and B-52 strategic bombers were much larger and had far greater performance and load-carrying ability than any of the World War II-era heavy or medium bombers. Other aircraft such as the twin- jet US FB-111 , Douglas A-3 Skywarrior and France 's Dassault Mirage IV had nominal warloads of less than 20,000 lb (9,100 kg), and were significantly smaller in size and gross weight compared with their strategic bomber contemporaries, based on which they might be classified as medium bombers . In

7224-448: Was renamed JSF in 1995; under the JSF program, contracts for flightworthy concept demonstrator aircraft were awarded in 1996 to Lockheed Martin and Boeing for the air vehicle designs and P&W for the initial propulsion system. P&W developed the JSF engine from their F119 turbofan, which powers the F-22 Raptor , as the "F119-JSF". A flightworthy prototype system that incorporated the shaft-driven lift fan, designated "YF119-PW-611",

7310-595: Was tested on the Lockheed Martin X-35 concept demonstrator aircraft and first flew in 2000. P&W also made another prototype, the "YF119-PW-614", for the competing Boeing X-32 which had direct lift system. In flight tests, the X-35B was able to demonstrate STOVL by taking off in 500 ft (150 m), then flew supersonic before landing vertically. The X-35 concept beat the X-32 for the JSF competition and

7396-450: Was widely employed , and atomic bombs were first used during World War II . Nuclear strike missions (i.e., delivering nuclear -armed missiles or bombs ) can potentially be carried out by most modern fighter-bombers and strike fighters , even at intercontinental range, with the use of aerial refueling , so any nation possessing this combination of equipment and techniques theoretically has such capability. Primary delivery aircraft for

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