F135 upgrades, reengining considered in new F-35 propulsion

[mixelflick]

Oh boy.... more thrust, lower fuel burn. On top of (already) the world's most powerful fighter engine..

This is really going to kill the boys working on the Idylize 30, LOL..

[weasel1962]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

[sprstdlyscottsmn]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

B-21 has two engines and won't have afterburner. It will be closer to 60,000lbt, but given that it is supposed to be half the size of a B-2 it will be fine.

[steve2267]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

B-21 has two engines and won't have afterburner. It will be closer to 60,000lbt, but given that it is supposed to be half the size of a B-2 it will be fine.

Have two engines been confirmed? I made a bet with someone around here that the B-21 will have two engines... I need to collect!

[sferrin]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

B-21 has two engines and won't have afterburner. It will be closer to 60,000lbt, but given that it is supposed to be half the size of a B-2 it will be fine.

So far as we know the engines haven't been identified. Sure, we assume they'll be non-afterburning F135s but I've seen nothing definitive.

[marauder2048]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

B-21 has two engines and won't have afterburner. It will be closer to 60,000lbt, but given that it is supposed to be half the size of a B-2 it will be fine.

So far as we know the engines haven't been identified. Sure, we assume they'll be non-afterburning F135s but I've seen nothing definitive.

The AFRL "Vision mission" definition for LRS subsonic ended up requiring a twin-engine 60,000 lbt configuration
(driven by takeoff requirements, 8,000 ft runway, sea-level 95 degree F day). It was a half sized B-2.

[weasel1962]

4 engines generating close to 200000 lbs of thrust. This could be one of the fastest bombers there is, not to mention the bomb loads.

B-21 has two engines and won't have afterburner. It will be closer to 60,000lbt, but given that it is supposed to be half the size of a B-2 it will be fine.

Have two engines been confirmed? I made a bet with someone around here that the B-21 will have two engines... I need to collect!

I think need to wait until end next year (or later). Understand there will be a public unveiling before the first flight.

[spazsinbad]

Pratt & Whitney Awarded Contract for F135 Engine Modernization Study
21 Oct 2020 SEApower STAFF

"EAST HARTFORD, Conn. — Pratt & Whitney, a division of Raytheon Technologies Corp., has been awarded a $1.5M contract to conduct an F135 modernization study and operational assessment by the F-35 Joint Program Office to determine specific propulsion system growth requirements for Block 4.2 F-35 aircraft and beyond, the company said in an Oct. 20 release. The study is expected to conclude in March 2021.

“This award is a significant milestone for the program and the warfighter, as we look to ensure the F135 propulsion system continues to provide the foundation for all air vehicle capability requirements over the full lifecycle of the F-35,” said Matthew Bromberg, president, Pratt & Whitney Military Engines. “As we look to the future, growth in aircraft capability must be met with matched propulsion modernization. Fortunately, the F135 has ample design margin to support agile and affordable upgrades that will enable all F-35 operators to keep pace with evolving threat environments.”

Under this award, Pratt & Whitney will assess F135 engine enhancements required to support future F-35 weapon system capability requirements across all F-35 variants beginning with Block 4.2 aircraft. The scope of the assessment focuses on enhancements addressing improvements to up and away thrust, powered lift thrust, power and thermal management capacity, and fuel burn reduction.

Designed with the knowledge that operational environments will evolve and threats will advance, the F135 is postured to meet future F-35 capability requirements. Its modular design and advanced digital architecture allow for the agile development and spiral insertion of both hardware and software upgrades. As part of the study, Pratt & Whitney’s GATORWORKS organization will complete the conceptual design and analysis of multiple F135 Engine Enhancement Package (EEP) growth options with phased insertion plans...."

Photo: "An F135-PW-100 engine, which powers the F-35 Joint Strike Fighter, undergoes salt water corrosion testing in the Arnold Engineering Development Complex SL-3 facility at Arnold Air Force Base, Tennessee, in 2016. U.S. Air Force / Christopher D. Rogers" https://seapowermagazine.org/wp-content ... 24x683.jpg
BiggaHugeA F135 PICtCha: https://seapowermagazine.org/wp-content ... Engine.jpg (10Mb)

Source: https://seapowermagazine.org/pratt-whit ... ion-study/

[mixelflick]

The scope of the assessment focuses on enhancements addressing improvements to up and away thrust, powered lift thrust, power and thermal management capacity, and fuel burn reduction.

And what would, "up and away" thrust be???

Thrust in the vertical?

[spazsinbad]

What is 'powered lift thrust' then?

[sprstdlyscottsmn]

Up and away sounds like dynamic thrust at speed and altitude. IIRC the F100-PW-200 had slightly lower rated thrust than the -100 but better dynamic thrust.

[doge]

The word Growth Option has disappeared and has been replaced by the word "EEP"? Name Change.
https://aviationweek.com/ad-week/f-35-p ... ncertainty

F-35 Propulsion Upgrade Moves Forward Despite Uncertainty
Steve Trimble July 21, 2020
Stabilizing the production system and securing a funded, long-term upgrade plan are now the main objectives for Pratt & Whitney’s F135 propulsion system for the Lockheed Martin F-35.
Although first delivered for ground--testing 17 years ago, the F135 remains a lifeline in Pratt’s combat aircraft engines portfolio for new-development funding. The U.S. military engines market is entering an era of transition with great uncertainty for the timing of the next major combat aircraft program.

Enhancement Package replaces “Growth Option”
New F-35 propulsion road map due in six months

The transition era begins with the likely pending delivery of Pratt’s most secretive development project. In 2016, the U.S. Air Force named Pratt as one of seven major suppliers for the Northrop Grumman B-21 bomber. The Air Force also has set the first flight of the B-21 for around December 2021. That timing means Pratt is likely to have delivered the first engine for ground-testing. At some point within the next year, Pratt should be planning to deliver the first flight-worthy engine to Northrop’s final assembly line in Palmdale, California, to support the Air Force’s first B-21 flight schedule.
As the bomber engine development project winds down, the propulsion system for the next fighter aircraft continues to be developed, but without a clear schedule for transitioning to an operational system.
The Air Force Research Laboratory’s Adaptive Engine Transition Program (AETP) is sponsoring a competition to develop an adaptive engine that can modulate the airflow into and around the core to improve fuel efficiency and increase range. The AETP competition is between Pratt’s XA101 and GE’s XA100 designs, with the first engines set to be delivered for ground-testing by the end of this year or early next year.

As 45,000-lb.-thrust-class engines, the first AETP designs are optimized for repowering the single-engine F-35, but the F-35 Joint Program Office (JPO) has established no requirement to replace the F135 for at least another five years. A follow-on effort within the AETP is developing a similar engine for a next-generation fighter, but neither the Air Force nor the Navy have committed to a schedule for transitioning the technology into an aircraft-development program. That leaves Pratt’s F135 as the only feasible application for inserting new propulsion technology for a decade more.
After spending the last decade focused on completing development of the F-35 and upgrading the software, electronics and mission systems, the JPO is developing a road map to improve the propulsion system through 2035.
As the road map is being developed, program officials also are seeking to stabilize the engine production system. Pratt delivered about 600 F135s to Lockheed through the end of last year, including 150—or about 25%—in 2019 alone. The JPO signed a $7.3 billion contract with Pratt last year to deliver another 509 engines in 2020-22, or about 170 a year.

Although Pratt exceeded the delivery goal in 2019 by three engines, each shipment came an average of 10-15 days behind the schedule in the contract. The fan, low-pressure turbine and nozzle hardware drove the delivery delays, according to the Defense Department’s latest annual Selected Acquisition Report on the F-35. Lockheed’s production schedule allows more than two weeks before the engine is needed for the final assembly line, so Pratt’s late deliveries did not hold up the overall F-35 schedule, says Matthew Bromberg, president of Pratt’s Military Engines business.
F135 deliveries finally caught up to the contract delivery dates in the first quarter of this year, but the supply chain and productivity disruptions caused by the COVID-19 pandemic have set the program back. About five engines scheduled for delivery in the second quarter fell behind the contractual delivery date, Bromberg says. The pressure will grow as a loaded delivery schedule in the second half of the year adds pressure on deliveries, but Pratt’s supply chain managers expect to be back within the contract dates in the first quarter of next year, he says.
The F-35 program’s political nature also has caused program disruptions. The Defense Department’s expulsion of Turkey from the F-35 program last year also banished the country’s supply chain, which contributed 188 parts to the F135. In particular, Alp Aviation produces the Stage 2, 3, 4 and 5 integrally bladed rotors (IBR) for the F135.

As of early July, about 128 parts now made in Turkey are ready to transition to other suppliers, of which about 80% are based in the U.S., according to Bromberg. The new suppliers should be requalified to produce those parts in the first quarter of 2021 and ready to meet production rate targets for Lot 15 aircraft, which will begin deliveries in 2023.
“The overriding objective was to move with speed and diligence along the transition plan and ensure we are ready to be fully out of Turkey by about Lot 15,” Bromberg explains. “And we are on track for that.”
As Pratt transfers suppliers, the company also has to manage the effect on potential upgrade options. Alp Aviation, for example, had announced a research and development program to convert the finished titanium IBRs to a more resilient nickel material.
For several years, Pratt has sought to improve the performance of the F135 above the baseline level. In 2017, the company unveiled the Growth Option 1.0 upgrade, which is aimed at delivering modular improvements that would lead to a 5% or 6% fuel-burn improvement and a 6-10% increase in thrust across the flight envelope. The Marine Corps, in particular, was seeking additional thrust to increase payload mass for a vertical landing, but the proposed package did not go far enough to attract the JPO’s interest.
“It missed the mark because we didn’t focus our technologies on power and thermal management,” Bromberg says.

A year later, Pratt unveiled the Growth Option 2.0. In addition to providing more thrust at less fuel burn, the new package offered to generate more electrical power to support planned advances in the aircraft’s electronics and sensors, with the ability to manage the additional heat without compromising the F-35’s signature in the infrared spectrum.
Last fall, the JPO’s propulsion management office teamed up with the Advanced Design Group at Naval Air Systems Command to analyze how planned F-35 mission systems upgrades will increase the load on the engine’s thrust levels and power generation and thermal management capacity. In May, the JPO commissioned studies by Lockheed and Pratt to inform a 15-year technology-insertion road map for the propulsion system. The road map is due later this year or in early 2021, with the goal of informing the spending plan submitted with the Pentagon’s fiscal 2023 budget request.
As the studies continue, a name change to Pratt’s upgrade proposals reveals a fundamental shift in philosophy. Pratt’s earlier “Growth Option” terminology is gone. The proposals are now called Engine Enhancement Packages (EEP). The goal of the rebranding is to show the upgrades no longer are optional for F-35 customers.

“As the engine provider and the [sustainment] provider, I’m very interested in keeping everything common,” Bromberg says. “The idea behind the Engine Enhancement Packages is they will migrate into the engines or upgrade over time. We don’t have to do them all at once. The [digital engine controls] will understand which configuration. That allows us again to be seamless in production, where I would presumably cut over entirely, but also to upgrade fleets at regularly scheduled maintenance visits.”
Pratt has divided the capabilities from Growth Options 1 and 2 into a series of EEPs, with new capabilities packaged in increments of two years from 2025 to 2029.
“If you go all the way to the right, you get all the benefits of Growth Option 2, plus some that we’ve been able to create,” Bromberg says. “But if you need less than that and you’re shorter on time or money, then you can take a subset of it.”

Meanwhile, the Air Force continues to fund AETP development as a potential F135 replacement. As the propulsion road map is finalized, the JPO will decide whether Pratt’s F135 upgrade proposals support the requirement or if a new engine core is needed to support the F-35’s thrust and power-generation needs over the long term.
Previously, Bromberg questioned the business case for reengining the F-35 by pointing out that a split fleet of F135- and AETP-powered jets erodes commonality and increases sustainment costs. Bromberg also noted it is not clear the third-stream technology required for the AETP can be accommodated within the roughly 4-ft.-dia. engine bay of the F-35B.
Now Bromberg says he is willing to support the JPO’s decision if the road map determines a reengining is necessary. “If the road map indicates that they need significantly more out of the engine than the Engine Enhancement Packages can provide, we would be the first to say an AETP motor would be required,” Bromberg says. “But we think a lot of the AETP technologies will make those Engines Enhancement Packages viable.”

https://www.flightglobal.com/fixed-wing ... 34.article

Pratt & Whitney contracted to study upgrading F135 engine
Garrett Reim By Garrett Reim22 October 2020
Pratt & Whitney has been awarded a $1.5 million contract by the F-35 Joint Program Office to study engine upgrade requirements for Block 4.2 and later iterations of the stealth fighter.
The company plans to conclude the assessment for the improvements needed for its F135 engine by March 2021, it said on 21 October. The study is focused on what is needed to improve the up and away thrust, powered lift thrust, electrical power and thermal management capacity, as well as what it would take to reduce fuel burn of the engine.
P&W’s prototyping arm, Gatorworks, plans to produce conceptual design and analysis of multiple F135 engine enhancement package options that could be added over time.
“This award is a significant milestone for the programme and the warfighter, as we look to ensure the F135 propulsion system continues to provide the foundation for all air vehicle capability requirements over the full lifecycle of the F-35,” says Matthew Bromberg, president of P&W Military Engines. “As we look to the future, growth in aircraft capability must be met with matched propulsion modernisation. Fortunately, the F135 has ample design margin to support agile and affordable upgrades that will enable all F-35 operators to keep pace with evolving threat environments.”
It is not clear what technologies could be added to the F135 to improve its performance.
The company mentions leveraging its work on “next-generation adaptive propulsion technologies”, which is part of a separate engine replacement development effort, called the Adaptive Engine Transition programme.
In 2018, P&W was awarded a $437 million contract by the US Air Force (USAF) to further develop its adaptive jet engine design, a new sort of turbine that can change the volume of air that flows to its core or bypass areas by opening and channelling air from a third stream. The USAF has said such a design could improve fuel consumption of an engine by 25%, which would increase an aircraft’s unrefuelled range. The extra air flow might also enable more thrust, or could be used for cooling purposes.
The Adaptive Engine Transition programme was intended to power the USAF’s sixth-generation fighter, the successor to the Lockheed F-22, and might also replace the F135 engine in the F-35 in the mid-2020s. P&W says it may draw upon technologies developed as part of that programme, but would not be assessing new adaptive engines as part of this specific study.
In parallel to F135 upgrade options, the company is continuing to develop new engines via the Adaptive Engine Transition programme, it says. ”These activities will inform development of the F-35 Propulsion Roadmap for 2035 which will be offered to US services and other F-35 partners for consideration later this year or in 2021,” says P&W.
The recently contracted F135 upgrade study seems to more closely resembles proposals put forward by P&W in 2017 and 2018.
In 2017, the company said it could offer drop-in thrust or fuel efficiency upgrades for the F135 in concert with the F-35’s Block 4.2 upgrade package. That so-called Growth Option 1.0 idea would improve the F135 engine’s thrust by 6% to 10% depending on the aircraft’s flight condition or reduce fuel consumption by 5%. The F135 generates 40,000lb-thrust (178kN) and the F-35A’s combat radius is 590nm (1,090km).
Changes as part of the Growth Option 1.0 would be limited to the F135 power module: the compressor, combustor and turbine. P&W claims that the limited nature of the changes would allow the upgrade programme to happen during routine depot maintenance.
In 2018, P&W followed up with Growth Option 2.0, another drop-in upgrade proposal that included the Growth Option 1.0 hardware, plus undisclosed adaptive engine technologies that would improve the F135’s electrical power generation and thermal management systems.
Improvements to engine electrical power generation and thermal management could be useful for planned F-35 upgrades including better electronic warfare capabilities, such as enhanced radar and radio communications jamming. Lockheed also said in September that it believes it could field a defensive laser on its F-16 fighter within five years. If such a weapon were to be fielded on the F-35 additional electrical power generation and a better thermal management system would be helpful.
Update: This article was changed on 22 October with additional comments and context from P&W.

Laser ! wow
I'm looking forward to it.

[alloycowboy]

The Pentagon is exploring its options for a more efficient and powerful F-35 engine

https://www.defensenews.com/air/2021/08 ... 35-engine/

“Candidly, I was impressed,” Fick said, adding that while “there’s a lot of work to be done before that becomes a production engine, before that becomes a reality for the F-35 program perhaps,” he would work with the services to explore alternative engine options.

While the F135 meets the Air Force’s current requirements, the service will have tested and garnered data from prototype AETP engines by the end of FY22, which will help inform future F135 upgrades, Air Force acquisition executive Darlene Costello said during the hearing.

Lt. Gen. David Nahom, the service’s deputy chief of staff for plans and programs, told lawmakers that the service is “very excited” about the increased power and efficiency the AETP engines could bring to the F-35. However, fielding it would require a “significant investment” that is not currently part of Air Force budget plans.

Right now, given the current top-line we have right now, we’re going to struggle to get any further with this technology,” he said.

Brig. Gen. Dale White, who leads the Air Force’s program office for advanced aircraft, poured even more cold water on the idea of upgrading the F135 with AETP technologies during a Aug. 12 roundtable with reporters.

“The technology that is inside AETP is very different than what we use on the fielded systems we have,” he said. “And so trying to change a power plant in … a fielded system is extremely complex, and there’s a lot that goes with that. And so you have to think about what the return on the investment might be there.”

[spazsinbad]

USAF: New Engine Technologies Can’t Be Retrofitted to Existing Fighters
12 Aug 2021 John A. Tirpak

"New engine technologies emerging from the Adaptive Engine Transition Program are “vastly different” from those now flying on Air Force fighters, so retrofitting the current force with the new power plants won’t be possible, the service’s program executive officer for fighters and advanced aircraft said Aug. 12.

The AETP technologies “really are future looking” and not applicable to existing fighters, Brig. Gen. Dale R. White told reporters in a press conference associated with the Air Force Life Cycle Management Center’s recent Life Cycle Industry Days symposium. The AETP, based on previous advanced engine programs, got underway in 2016, and full-scale engine tests have been conducted this year. General Electric’s version is the XA-100, while Pratt & Whitney’s is the XA-101. The AETP is developing power plants using third-stream airflow to combine fuel-sipping benefits during cruise with quick-reaction high thrust, as needed in fighter engagements....

...the technologies in AETP are “very different than what we use on the fielded systems that we have,” he said. Where there are opportunities to make them “backward compatible,” that will be done, but White suggested there have been few such instances. Changing the propulsion system on a fielded aircraft is “extremely complex, and there’s a lot that goes with that,” White said. “So you have to think about what the return on investment might be, there.”...

...Air Force and Pentagon leaders have hinted that future versions of the F-35 fighter could use new engines developed under AETP to save on fuel and gain performance. Even newly minted Air Force Secretary Frank Kendall suggested as much in his first interview with Air Force Magazine.

But White’s comments indicate that while the F-35’s F135 engine can be improved, it won’t be replaced by whatever emerges from AETP. Senior Air Force leaders have said in testimony this spring that wholesale replacement of engines already in service is not affordable within anticipated budgets.

Pratt & Whitney, maker of the F135, proposed a package of improvements for the engine to the Joint Program Office in March, which the JPO is evaluating."

Photo: "Teams have completed testing an adaptive three-stream fan in the J2 Engine Test Facility at Arnold Air Force Base, Tenn. The testing for Pratt & Whitney was part of the Air Force Research Laboratory’s Adaptive Engine Technology Development program. Photo courtesy of Pratt & Whitney." https://www.airforcemag.com/app/uploads ... ngine.jpeg

Source: https://www.airforcemag.com/usaf-new-en ... -fighters/

[quicksilver]

I’ve always wondered how much margin they have left with the current inlet geometry.