Pratt & Whitney XA101

Last updated
XA101
PW 3 stream fan test.jpg
XA101 adaptive fan being tested at Arnold Engineering Development Complex (AEDC)
Type Adaptive cycle engine
National originUnited States
Manufacturer Pratt & Whitney
First run2021
Major applications Lockheed Martin F-35 Lightning II (proposed)

The Pratt & Whitney XA101 is an American adaptive cycle engine demonstrator being developed by Pratt & Whitney for the Lockheed Martin F-35 Lightning II and form the technological foundation for the company's XA103 propulsion system for the United States Air Force's sixth generation fighter program, the Next Generation Air Dominance (NGAD).

Contents

The three-stream adaptive cycle design can direct air to the bypass third stream for increased fuel efficiency and cooling or to the core and fan streams for additional thrust and performance. The 45,000 lbf (200 kN) thrust class engine is expected to be significantly more powerful and efficient than existing low-bypass turbofans.

Development

The U.S. Air Force and U.S. Navy began pursuing the adaptive cycle engine concept in 2007 with the Adaptive Versatile Engine Technology (ADVENT) program, a part of the larger Versatile Affordable Advanced Turbine Engines (VAATE) program. [1] While not involved with ADVENT, Pratt & Whitney was selected alongside General Electric for the Adaptive Engine Technology Demonstrator (AETD) program that followed in 2012; this program continued to mature the technology, with tests performed using demonstrator engines. The next step, the Adaptive Engine Transition Program (AETP), [2] was launched in 2016 to develop adaptive engines for sixth-generation fighter propulsion as well as potential re-engining of the F-35 from the existing F135 turbofan engine. The General Electric demonstrator was designated XA100 and the P&W engine was designated XA101. The AETP goal was to demonstrate 25% improved fuel efficiency, 10% additional thrust, and improved thermal management. [3]

In 2017, Pratt & Whitney successfully tested an adaptive three-stream fan with an F135 core, and considered the XA101 to be "Growth Option 2.0" in its long-term development plan for the F135. [4] [5] [6] Further contract awards and modifications from Air Force Life Cycle Management Center (AFLCMC) in 2018 increased the focus on re-engining of the F-35; there has also been investigations on applying the technology in upgrades for F-15, F-16, and F-22 propulsion systems. [7] In June 2018, Pratt & Whitney changed its development plan for the F135, and instead offered an adaptive three-stream fan as Growth Option 2.0 that is separate from the XA101, which would instead have a new engine core. [8] [9] In 2020, the F135 development plan shifted from "Growth Options" to "Engine Enhancement Packages" (EEP), while the three-stream XA101 is a new engine with potential re-engining for the F-35A. Ground testing of the XA101 began in September 2021. [10]

Also in September 2021, Pratt & Whitney publicly stated serious doubts about the cost effectiveness of AETP's future for the F-35, stating that the XA101 was "always intended … to be a sixth-generation [powerplant for sixth-generation fighters]." Jennifer Latka, Vice President of the F135 program, explained: “There’s a significant amount of risk that comes with brand-new technology, and that would require a tremendous amount of validation to be done. We’re saying, the AETP is not the right fit for the F-35.” Instead, Pratt & Whitney is proposing a "drop-in" enhanced engine package that would improve thrust and range by 10% while also offering a 50% improvement in thermal management. While this falls short of the AETP's goal of a 25% improvement in fuel efficiency, Pratt & Whitney argues the savings would be worth it, estimating the cost of developing AETP for the F-35 at up to $40 Billion. [11] As of 2021, thermal management had been an ongoing issue for the F135, largely due to the increased sustainment and maintenance costs caused from heat damage by running the engines hotter in order to take full advantage of newer, more powerful sensors and electronics being integrated into Block 4+ F-35s. The sensors and electronics subsequently require additional cooling to take full advantage of the aircraft's capability. GE had previously stated that one advantage of their AETP XA100 engine is its third airstream, which its officials say can be used to help cool the F-35’s electronics. Nonetheless, Latka urged an official review of the program's requirements, stating, “We need to crystallize on what the requirement is, and then we figure out what the most cost-effective solution is once we understand that requirement." [11]

In 2023 the USAF chose an improved F135 under the Engine Core Upgrade (ECU) program over an adaptive cycle engine such as the XA101 due to cost as well as concerns over risk of integrating the new engine, initially designed for the F-35A, on the B and C. [12]

Design

The XA101 is a three-stream adaptive cycle engine that can adjust the bypass ratio and fan pressure to increase fuel efficiency or thrust, depending on the scenario. It does this by employing a third bypass stream around the entire engine, with the ability to modulate the portion of airflow into the engine core or through this third stream, to increase fuel economy and act as a heat sink for cooling. This capability enables greater use of the high-speed, low-altitude portion of the F-35 flight regime. The increased cooling and power generation also enables the potential employment of directed-energy weapons in the future. When additional thrust is needed, the air from the third stream can be directed into the core and fan streams for increased performance. [2]

Applications

Specifications (XA101-PW-100)

Data from Flight Global, [7]

General characteristics

Components

Performance

See also

Related development

Comparable engines

Related lists

Related Research Articles

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A jet engine is a type of reaction engine, discharging a fast-moving jet of heated gas that generates thrust by jet propulsion. While this broad definition may include rocket, water jet, and hybrid propulsion, the term jet engine typically refers to an internal combustion air-breathing jet engine such as a turbojet, turbofan, ramjet, pulse jet, or scramjet. In general, jet engines are internal combustion engines.

<span class="mw-page-title-main">Turbofan</span> Airbreathing jet engine designed to provide thrust by driving a fan

A turbofan or fanjet is a type of airbreathing jet engine that is widely used in aircraft propulsion. The word "turbofan" is a combination of references to the preceding generation engine technology of the turbojet and the additional fan stage. It consists of a gas turbine engine which achieves mechanical energy from combustion, and a ducted fan that uses the mechanical energy from the gas turbine to force air rearwards. Thus, whereas all the air taken in by a turbojet passes through the combustion chamber and turbines, in a turbofan some of that air bypasses these components. A turbofan thus can be thought of as a turbojet being used to drive a ducted fan, with both of these contributing to the thrust.

<span class="mw-page-title-main">Afterburner</span> Turbojet engine component

An afterburner is an additional combustion component used on some jet engines, mostly those on military supersonic aircraft. Its purpose is to increase thrust, usually for supersonic flight, takeoff, and combat. The afterburning process injects additional fuel into a combustor in the jet pipe behind the turbine, "reheating" the exhaust gas. Afterburning significantly increases thrust as an alternative to using a bigger engine with its attendant weight penalty, but at the cost of increased fuel consumption which limits its use to short periods. This aircraft application of "reheat" contrasts with the meaning and implementation of "reheat" applicable to gas turbines driving electrical generators and which reduces fuel consumption.

<span class="mw-page-title-main">Bypass ratio</span> Proportion of ducted compared to combusted air in a turbofan engine

The bypass ratio (BPR) of a turbofan engine is the ratio between the mass flow rate of the bypass stream to the mass flow rate entering the core. A 10:1 bypass ratio, for example, means that 10 kg of air passes through the bypass duct for every 1 kg of air passing through the core.

<span class="mw-page-title-main">Lockheed Martin X-35</span> Concept demonstrator aircraft for Joint Strike Fighter program

The Lockheed Martin X-35 is a concept demonstrator aircraft (CDA) developed by Lockheed Martin for the Joint Strike Fighter program. The X-35 was declared the winner over the competing Boeing X-32 and a developed, armed version went on to enter production in the early 21st century as the F-35 Lightning II.

<span class="mw-page-title-main">General Electric/Rolls-Royce F136</span> Never completed engine for the Lockheed Martin F-35 Lightning II

The General Electric/Rolls-Royce F136 was an afterburning turbofan engine being developed by General Electric, Allison Engine Company, and Rolls-Royce as an alternative powerplant to the Pratt & Whitney F135 for the Lockheed Martin F-35 Lightning II. The two companies stopped work on the project in December 2011 after failing to gather Pentagon support for further development.

<span class="mw-page-title-main">General Electric F110</span> Aircraft engine

The General Electric F110 is an afterburning turbofan jet engine produced by GE Aerospace. It was derived from the General Electric F101 as an alternative engine to the Pratt & Whitney F100 for powering tactical fighter aircraft, with the F-16C Fighting Falcon and F-14A+/B Tomcat being the initial platforms; the F110 would eventually power new F-15 Eagle variants as well. The engine is also built by IHI Corporation in Japan, TUSAŞ Engine Industries (TEI) in Turkey, and Samsung Techwin in South Korea as part of licensing agreements.

<span class="mw-page-title-main">Boeing X-32</span> Multirole combat aircraft prototype by Boeing

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<span class="mw-page-title-main">Pratt & Whitney F119</span> American low-bypass turbofan engine for the F-22 Raptor

The Pratt & Whitney F119, company designation PW5000, is an afterburning turbofan engine developed by Pratt & Whitney for the Advanced Tactical Fighter (ATF) program, which resulted in the Lockheed Martin F-22 Raptor. The engine delivers thrust in the 35,000 lbf (156 kN) class and was designed for sustained supersonic flight without afterburners, or supercruise. Delivering almost 22% more thrust with 40% fewer parts than its F100 predecessor, the F119 allows the F-22 to achieve supercruise speeds of up to Mach 1.8. The F119's nozzles incorporate thrust vectoring that enable them to direct the engine thrust ±20° in the pitch axis to give the F-22 enhanced maneuverability.

<span class="mw-page-title-main">Pratt & Whitney F135</span> Afterburning turbofan aircraft engine

The Pratt & Whitney F135 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.

<span class="mw-page-title-main">General Electric TF39</span> Turbofan aircraft engine

The General Electric TF39 is a high-bypass turbofan engine that was developed to power the Lockheed C-5 Galaxy. The TF39 was the first high-power, high-bypass jet engine developed. The TF39 was further developed into the CF6 series of engines, and formed the basis of the LM2500 and LM6000 marine and industrial gas turbine. On September 7, 2017, the last active C-5A powered with TF39 engines made its final flight to Davis-Monthan Air Force Base for retirement. The TF39 was effectively retired, and all remaining active C-5 Galaxies are Rebuilt C-5M Super Galaxies, powered by F138-GE-102 engines.

<span class="mw-page-title-main">Pratt & Whitney F100</span> Afterburning turbofan engine that powers the F-15 Eagle and F-16 Fighting Falcon

The Pratt & Whitney F100 is a low bypass afterburning turbofan engine. It was designed and manufactured by Pratt & Whitney to power the U.S. Air Force's "FX" initiative in 1965, which became the F-15 Eagle. The engine was to be developed in tandem with the F401 which shares a similar core but with an upscaled fan for the U.S. Navy's F-14 Tomcat. The F401 was later abandoned due to costs and reliability issues. The F100 also powered the F-16 Fighting Falcon for the Air Force's Lightweight Fighter (LWF) program.

<span class="mw-page-title-main">General Electric YF120</span> American fighter variable-cycle turbofan engine

The General Electric YF120, internally designated as GE37, was a variable cycle afterburning turbofan engine designed by General Electric Aircraft Engines in the late 1980s and early 1990s for the United States Air Force's Advanced Tactical Fighter (ATF) program. It was designed to produce maximum thrust in the 35,000 lbf (156 kN) class. Prototype engines were installed in the two competing technology demonstrator aircraft, the Lockheed YF-22 and Northrop YF-23.

<span class="mw-page-title-main">Variable cycle engine</span> Aircraft propulsion system efficient at a range of speeds higher and lower than sounds

A variable cycle engine (VCE), also referred to as adaptive cycle engine (ACE), is an aircraft jet engine that is designed to operate efficiently under mixed flight conditions, such as subsonic, transonic and supersonic.

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<span class="mw-page-title-main">Adaptive Versatile Engine Technology</span> US aircraft engine development program

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<span class="mw-page-title-main">General Electric XA100</span> American adaptive cycle engine

The General Electric XA100 is an American adaptive cycle engine demonstrator being developed by General Electric (GE) for the Lockheed Martin F-35 Lightning II and form the technological foundation for the company's XA102 propulsion system for the United States Air Force's sixth generation fighter program, the Next Generation Air Dominance (NGAD).

<span class="mw-page-title-main">Pratt & Whitney F401</span> Turbofan Engine

The Pratt & Whitney F401 was an afterburning turbofan engine developed by Pratt & Whitney in tandem with the company's F100. The F401 was intended to power the Grumman F-14 Tomcat and Rockwell XFV-12, but the engine was canceled due to costs and development issues.

The General Electric XA102 is an American adaptive cycle engine demonstrator being developed by General Electric (GE). It is competing with the Pratt & Whitney XA103 as the powerplant for the United States Air Force's sixth generation fighter program, the Next Generation Air Dominance (NGAD).

The Pratt & Whitney XA103 is an American adaptive cycle engine demonstrator being developed by Pratt & Whitney. It is competing with the General Electric XA102 as the powerplant for the United States Air Force's sixth generation fighter program, the Next Generation Air Dominance (NGAD).

References

    1. ↑ Thomson, Daniel E. (14 April 2010). Versatile Affordable Advanced Turbine Engines Provide Game Changing Capability with Superior Fuel Efficiency (PDF). 11th Annual Science & Engineering Technology Conference/DoD Tech Expo. Charleston, South Carolina.
    2. 1 2 Jim Mathews (26 June 2017). "Engines of Innovation". Air Force Magazine. Retrieved 14 May 2021.
    3. ↑ Mehta, Aaron (1 July 2016). "US Air Force Funds Next Advanced Engine Stage". DefenseNews. Retrieved 11 January 2020.
    4. ↑ Kjelgaard, Christ (15 June 2017). "P&W Outlines Three-step F135 Development Pathway". Aviation International News. Retrieved 11 January 2020.
    5. ↑ Insinna, Valerie (18 September 2017). "Eyeing the future fighter, Pratt & Whitney hits milestone with new adaptive engine". DefenseNews. Retrieved 11 January 2020.
    6. ↑ Norris, Guy (29 January 2015). "GE Details Sixth-Generation Adaptive Fighter Engine Plan". Aviation Week. Retrieved 11 January 2020.
    7. 1 2 Trimble, Steven (9 July 2018). "USAF starts work on defining adaptive engine for future fighter". Flight Global. Retrieved 11 January 2020.
    8. ↑ Kjelgaard, Chris (13 June 2018). "P&W Outlines New Plan for F-35 Engine Upgrades". Aviation International News. Retrieved 11 January 2020.
    9. ↑ Norris, Guy; Anselmo, Joe (21 July 2018). "F-35 Engine Upgrade Would Enable Directed Energy Weapons". Aviation Week. Retrieved 11 January 2020.
    10. ↑ Tirpak, John A. (1 October 2021). "Pratt Testing XA101 Adaptive Engine, Has Two Offerings for F-35 Propulsion". Air Force Magazine.
    11. 1 2 Tirpak, John A. (2021-09-09). "Pratt Pushes Alternative to New Adaptive Engine for F-35". Air Force Magazine. AirForceMagazine.com. Retrieved 2022-04-17.
    12. ↑ Marrow, Michael (13 March 2023). "Air Force will not develop new F-35 engine, keeping Pratt as sole contractor". Breaking Defense.
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