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USAF/US NAVY 6th Generation Fighter Programs - F/A-XX, F-X, NGAD, PCA

tacitblue

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bobbymike said:
Time for Air Dominance

—John A. Tirpak

4/10/2015

The Air Force’s forecast that the F-22 will last into the 2040s helps explain why the service seems in no rush to launch a sixth-generation fighter program. Reporters have been peppering the Air Force and DOD leadership with queries as to why there’s no F-22 replacement in the budget, since it took 20 years to develop the Raptor from drawing board to initial operating capability, and the F-22 was thought to be retiring in about 2035. The Pentagon and USAF leaders have responded that they are undertaking an “Air Dominance 2030” study that will analyze such technologies as hypersonics and directed energy to determine what mix of attributes will give the US air superiority/air dominance 15 years hence. Apparently, the clock will not run out on the Raptor before its replacement capability is in hand. Asked about a sixth-generation fighter at the AFA Air Warfare Symposium in February, Chief of Staff Gen. Mark Welsh said, “I don’t know what it looks like,” and “it may not be a single platform,” but a family of systems, not unlike the service’s concept for long-range strike.
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This doesn't make sense to me don't we need 6th Gen to also replace F-15s in the air superiority role or in 2030 we will have 180 or so F-22s to cover the whole planet? And back to an earlier observation I will live to only see one more generation of aircraft and probably no hypersonic aircraft (maybe a weapon or two) either :'(
If we needed it, we would have it tomorrow. You don't honestly believe leadership is going to telegraph what they do out there in that back hole patch of desert do you? But they've bet the farm (and the ranch) on the 35 with the 22 playing as a silver bullet force akin to the 117s role.
 

Triton

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Your mileage may vary. Personally, I believe that claims of the death of the manned fighter aircraft are exaggerated.

"Mabus: F-35 Will Be ‘Last Manned Strike Fighter’ the Navy, Marines ‘Will Ever Buy or Fly’"
by Sam LaGrone
April 15, 2015 1:55 PM • Updated: April 15, 2015 2:30 PM

Source:
http://news.usni.org/2015/04/15/mabus-f-35c-will-be-last-manned-strike-fighter-the-navy-marines-will-ever-buy-or-fly

NATIONAL HARBOR, Md. Secretary of the Navy Ray Mabus said the Lockheed Martin F-35 Joint Strike Fighter (JSF) will be “almost certainly will be, the last manned strike fighter aircraft the Department of the Navy will ever buy or fly,” signaling key assumptions in the Navy’s aviation future as the service prepares to develop follow-ons to the Boeing F/A-18E/F Super Hornet.

“Unmanned systems, particularly autonomous ones, have to be the new normal in ever-increasing areas,” Mabus said.
For example, as good as it is, and as much as we need it and look forward to having it in the fleet for many years, the F-35 should be, and almost certainly will be, the last manned strike fighter aircraft the Department of the Navy will ever buy or fly.”
To address the emerging role unmanned weapon systems, Mabus announced a new deputy assistant secretary of the Navy for unmanned systems and a new Navy staff position — alongside warfare directorates like surface and air warfare — N-99.

The positions were created “so that all aspects of unmanned – in all domains – over, on and under the sea and coming from the sea to operate on land – will be coordinated and championed,” Mabus said.

Unmanned aerial vehicles are currently part of the Navy’s N2/N6 Information Dominance portfolio as primarily information, surveillance and reconnaissance (ISR) platform while undersea and surface unmanned systems are owned by a myriad of agencies.

Unlike the Air Force, the Navy doesn’t not currently have armed UAVs and is currently developing a carrier UAV — Unmanned Carrier-Launched Airborne Surveillance and Strike (UCLASS — which would contain the service’s first planned unmanned strike platform.

The UCLASS development program is planned to operate under the current E-2 Hawkeye command structure.

The remarks at the Navy League’s Sea-Air-Space 2015 Exposition also comes as the Navy is preparing for studies for the service’s next generation fighter effort — F/A-XX — that will replace the existing Super Hornets.

The planned fiscal year 2016 analysis of alternatives (AoA) for F/A-XX will weigh a myriad of options that could translate to a capability that might not necessarily be a single aircraft but a could be a myriad of manned and unmanned capability, USNI News understands.

Chief of Naval Operations (CNO) Adm. Jonathan Greenert said earlier this year that F/A-XX will likely be optionally manned.

Though Mabus mentioned strike — which the service defines as attacking land and surface targets — he did not address fighter on fighter air warfare that would be a different capability set.
 

bobbymike

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Last sentence is key

"Though Mabus mentioned strike — which the service defines as attacking land and surface targets — he did not address fighter on fighter air warfare that would be a different capability set."

Means F/A-XX with likely just be F-XX?? ;)
 

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-The planned fiscal year 2016 analysis of alternatives (AoA) for F/A-XX will weigh a myriad of options that could translate to a capability that might not necessarily be a single aircraft but a could be a myriad of manned and unmanned capability, USNI News understands.-

makes sense.
 

bobbymike

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http://www.defensenews.com/story/military/2015/04/22/welsh-future-aircraft-pilots-needed/26178677/
 

bobbymike

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The Skunk Works Path to 6th Gen

—John A. Tirpak

4/27/2015

​Palmdale, Calif.—Lockheed Martin’s Skunk Works shop is taking a three-pronged approach to figuring out what Air Dominance in 2030 looks like, according to Skunk Works Vice President and General Manager Rob Weiss. In an exclusive interview, Weiss told Air Force Magazine that his outfit is doing operational analyses and “wargaming … to understand what advantages we have today” versus potential adversaries and what’s needed five to 30 years from now. First, Skunk Works has to figure out how to “connect all the systems we have operational today,” among air, surface and subsurface platforms, to derive the best possible power. Second is to determine “the appropriate modernization paths” for today’s systems, and “how do we implement that modernization in the most affordable way?” Weiss said Lockheed is not only looking at how to improve its own F-22 and F-35 systems, but those of competitors as well, as it may compete for those upgrades. However, the more compelling reason is because finding where the “capability gaps” will be two decades hence won’t make any sense “unless you look across all the systems out there.” Skunk Works’ third goal is to deduce how much of a “new capability insertion” is really required, Weiss said. “What specifically is the gap, and what is the range of solutions that can be provided to fill that gap?” He thinks “there could be a new platform in the equation,” but the analysis isn’t finished yet.
 

bring_it_on

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Air Force Standing Up Team To Wrestle With Future Air Dominance Requirements


The Air Force is standing up a team to wrestle anew with requirements for a follow-on capability to the F-22A, the U.S. military's premier fighter aircraft, the latest development in a fledgling effort to identify exactly what the U.S. military will need in the 2030s to retain global air dominance.
On April 22, Deputy Defense Secretary Robert Work sent Congress the Pentagon's latest 30-year aircraft plan. The 38-page report required by law summarizes how the U.S. military intends to maintain its combat aviation capabilities and includes the first mention of the new team in a public document.
"The Air Force is organizing an Air Superiority Enterprise Capability Collaboration Team to shape its activities around the mission effects chains to identify and quantify key capabilities and explore the full range of potential material and non-material solutions addressing future air superiority," the report states.
This codifies what Air Force leaders began publicly touting in mid-February as the vanguard of a new campaign to form "capability collaboration teams" to revive a capability development planning process set aside in 1992 when the service eliminated its Systems Command.
Last summer, the Air Force commenced a new-start, next-generation air dominance research and development project with $15.7 million in fiscal year 2015 funding. The project -- the product of nearly a decade of Air Force thinking about it future air dominance needs -- aims to build the case for a potential bona fide development and acquisition program, informally referred to as a sixth-generation fighter, as soon as the summer of 2016.
In building the case for what will follow the Raptor, the Air Force plans a wide range of activities, including operational analyses, according to the service's FY-16 budget request, as well as threat studies and technology candidate assessments to identify operational concepts and technologies that improve persistence, survivability, lethality, connectivity, interoperability and affordability in 2030.
"In the far term, the Air Force will need to capitalize its current 4th and 5th generation air superiority capability," the new report states. "Future research and development efforts beyond the [FY-16 to FY-20 future years defense plan] will focus on improvements to fifth-generation aircraft and initial RDT&E for an F-22 capability replacement," according to the report.
In February 2013, the Joint Requirements Oversight Council approved the Air Force's new fighter requirement and directed the service to accomplish a joint analysis of alternatives with the Navy once the JROC approves the Navy's Next Generation Air Dominance Family of Systems initial capabilities document. Pentagon officials initially projected the Navy to present its requirement for a follow-on capability for the F/A-18E/F and EA-18G in early 2014. As of February, the service did not have a JROC-validated requirement, according to Navy spokesman Lt. Robert Myers.
While the Navy did not formally request a budget for a next-generation fighter, last fall Congress added a $5 billion research and development program in the service's FY-15 budget. In February, the Navy asked for $5 million in FY-16 for the next-generation fighter.
The "Annual Aviation Inventory and Funding Plan, Fiscal Years 2016 to 2045" sent to Congress last week does not suggest the Navy is advancing its work on a next-generation fighter. The report largely restates information DOD outlined in the 30-year plan sent to Congress in 2014.
"In the far term, the Navy will need to replace its F/A-18E/F and EA-18G fleet starting in the 2030 timeframe," the report sent to Congress last week states. "The Navy is conducting analyses to inform a decision to include consideration of a family of systems -- mixes of manned and unmanned aircraft with advanced propulsion technologies, with varying stealth characteristics, advanced standoff weapons, sensors and networks," the report states. -- Jason Sherman
http://insidedefense.com/node/169100
 

bring_it_on

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More on ASISTT (Advanced Staring Infrared Search and Track Technologies )

The objective of the Advanced Staring Infrared Search and Track Technologies (ASISTT) Program is to identify, mature and demonstrate technology solutions supporting the development of a future airborne long range offensive infrared search and track (IRST) capability based on staring (non-scanned) system configurations. The offensive capability to be developed requires Weapons Quality Tracks (WQT) of airborne targets under clear air and in clutter conditions. This research and development effort in staring IRST systems is in contrast to current offensive IRST implementations using gimbaled optics and smaller scanning format arrays.

The ASISTT Program will develop a staring IRST technology demonstrator in a flyable brassboard configuration that can be used in a series of performance verification/validation experiments and demonstrations. The purpose is to reduce technology risk by determining and maturing appropriate technologies needed for integration into a demonstration system capable of operating in a flight environment in order to demonstrate system level performance metrics.
The scope of this effort covers the analysis, design, manufacture, test and performance assessment of the requisite technologies needed to develop an offensive staring IRST with long range detection and tracking of airborne targets. This effort encompasses design and trade study analyses, sensor hardware development, detection and tracking algorithm development and/or implementation and field/flight experiment support.

General Operations Security (OPSEC) procedures, policies and awareness are required in an effort to reduce program vulnerability from successful adversary collection and exploitation of critical information. OPSEC will be applied throughout the life cycle of the contract. The Critical Information List (CIL) will be provided upon request by RYOY Information Protection Office. While working on the government installation, OPSEC guidance will be provided by the RYOY Information Protection Office.
https://www.scribd.com/doc/265780223/BAA-RQKS-2015-0005-NOCA
 

bobbymike

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Air Force launches air superiority Enterprise Capability Collaboration Team

By Secretary of the Air Force Public Affairs, / Published May 19, 2015

WASHINGTON (AFNS) -- The Air Force recently launched the first Enterprise Capability Collaboration Team (ECCT), kicking off an initiative that integrates expertise from around the service in an effort to deliver innovative solutions to capabilities issues.

Chief of Staff of the Air Force Gen. Mark A. Welsh III chartered the first ECCT with the task of exploring the air superiority mission with an eye toward the year 2030 and beyond. They will spend the next year focusing on delivering capability options in projected future operating environments, ultimately delivering courses of action to support acquisition activities and related efforts geared toward ensuring long-term air dominance independent of a reliance on specific platforms.

“Gaining and maintaining air superiority is foundational to how we fight,” Welsh said. “The air superiority this nation has enjoyed for 60 years is not an accident and gaining and maintaining it is not easy.”

“It requires trained proficient and ready Airmen and it requires credible, capable and technologically superior aircraft,” he said.

The makeup of the air superiority 2030 team will span a wide spectrum of the service’s pool of experts, providing it the ability to accurately consider the air superiority needs of combatant commands and sister services and how the Air Force can best meet those needs.

“Planning for the future requires a full and integrated understanding of the ways Air Force and service capabilities work together to deliver joint warfighting effects,” said Lt. Gen. James M. Holmes, the deputy chief of staff for strategic plans and requirements. “The ECCT will bring together users and operators from all Air Force domains and core functions, along with the requirements, acquisition and science and technology communities to collaboratively examine, comprehend and quantify operational needs and propose defendable, achievable and affordable solutions.”

As their project matures over the course of the year, the ECCT will consider both materiel and non-materiel solutions as a means to fill capability gaps. This could include examining new technologies by leveraging wargaming, experimentation, and modeling and simulation, and providing the team opportunities to review and assess capabilities options across multiple geographic regions and warfighting domains, both contested and non-contested.

“Focusing on capability solutions means we first explore and research the concepts and technologies we need to meet current and future requirements,” Holmes said. “Then we can look at how we would apply these concepts and technologies across any number of platforms, organizations and domains. In the end, that could mean modernizing a current platform, using current platforms and sensors in new ways, or investing in a new platform to meet national strategic objectives.”

At the conclusion of their year-long endeavor, ECCTs will deliver options to Air Force senior leaders that identify, refine and mature the most feasible solutions to fill capability gaps.

The Air Force will stand up a limited number of the ECCTs focusing on high-priority, enterprise-wide problems.
 

pedrospe

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I just saw this picture on Aldo Spadoni facebook,(thanks to Triton that shared is linkpage),this aircraft looks like an Fa-xx concept from Northrop Grumman,but what i found weird was the weapons bay on top of the aircraft,and the missile looks like a agm-137...


 

AeroFranz

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VERY interesting. It looks like a single-seater (curious choice), obviously a mothership for UAVs which serve as force multipliers. And it looks like besides dropping them, the mothership also recovers them. Any other info on this?
 

flateric

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AeroFranz said:
VERY interesting. It looks like a single-seater (curious choice), obviously a mothership for UAVs which serve as force multipliers. And it looks like besides dropping them, the mothership also recovers them. Any other info on this?
Aldo says it's just a fast-made concept to show an idea of uav mothership, that was made using ready 3D models.
 

flateric

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sferrin said:
I'm wondering what this thing is:
It's from New World Vistas 1995 study, volume 'Aircraft&Propulsion'
 

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AeroFranz

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flateric said:
AeroFranz said:
VERY interesting. It looks like a single-seater (curious choice), obviously a mothership for UAVs which serve as force multipliers. And it looks like besides dropping them, the mothership also recovers them. Any other info on this?
Aldo says it's just a fast-made concept to show an idea of uav mothership, that was made using ready 3D models.

Thanks! i was wondering how worked out the concept was. This is the first time i saw it, and it's one of the first pictures i see of a concept i think will eventually be realized. Some problems remain to be solved, like the stability of UAVs while in tow. With long tow-line distances (like aerial refueling) it should be ok, but as you shorten the length, you might get into some oscillations that can prevent retrieval.
 

jsport

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AeroFranz said:
flateric said:
AeroFranz said:
VERY interesting. It looks like a single-seater (curious choice), obviously a mothership for UAVs which serve as force multipliers. And it looks like besides dropping them, the mothership also recovers them. Any other info on this?
Aldo says it's just a fast-made concept to show an idea of uav mothership, that was made using ready 3D models.

Thanks! i was wondering how worked out the concept was. This is the first time i saw it, and it's one of the first pictures i see of a concept i think will eventually be realized. Some problems remain to be solved, like the stability of UAVs while in tow. With long tow-line distances (like aerial refueling) it should be ok, but as you shorten the length, you might get into some oscillations that can prevent retrieval.
Tubal Triangle to the rescue (Tubal Ryan that is..sometimes known as T. Claude Ryan) maybe..maybe someone earlier
 

bobbymike

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http://www.military.com/daily-news/2015/06/17/navy-air-force-to-develop-sixth-generation-unmanned-fighter.html?comp=7000023317843&rank=1
 

marauder2048

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AeroFranz said:
flateric said:
AeroFranz said:
VERY interesting. It looks like a single-seater (curious choice), obviously a mothership for UAVs which serve as force multipliers. And it looks like besides dropping them, the mothership also recovers them. Any other info on this?
Aldo says it's just a fast-made concept to show an idea of uav mothership, that was made using ready 3D models.


Thanks! i was wondering how worked out the concept was. This is the first time i saw it, and it's one of the first pictures i see of a concept i think will eventually be realized. Some problems remain to be solved, like the stability of UAVs while in tow. With long tow-line distances (like aerial refueling) it should be ok, but as you shorten the length, you might get into some oscillations that can prevent retrieval.
I'm skeptical that sacrificing the internal volume on the mothership to accommodate the hoses, fuel handling equipment and separate JP-10 fuel tanks is worth the tactical utility.
 

AeroFranz

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That would be impractical. No, in all likelihood the UAVs would have to run on the same JP-8 as the mothership. i think the picture is just representative at this point.
 

bring_it_on

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President Barack Obama’s inclusion of a funding allocation for a four-year Adaptive Engine Transition Programme (AETP) in his Fiscal 2016 annual budget request to the US Congress has focused attention on the research efforts that both GE Aviation and Pratt & Whitney are conducting for the Air Force Research Laboratory (AFRL) on variable-cycle turbofan engines for next-generation fighters.
Should Congress approve President Obama’s request, the four-year Adaptive Engine Technology Development (AETD) research projects on which the two US- based manufacturers have been working since 2012 (and which are due to end with demonstrations of their designs before the end of 2016) would undergo a quick transition into a full development effort. Other than vetoing outright President
Obama’s AETP budget request, it’s possible that Congress might choose only one of the two AETD designs under development to move towards volume production. That would depend on the Pentagon’s view on which of the two manufacturers’ designs holds most promise in terms of performance, reliability and cost.

Congress could also choose to allow development of both AETD designs to proceed through the engineering, manufacturing and development phases of the AETP into full production. This would happen if Congress felt sales competition between the two manufacturers represented the best way to keep overall engine- purchasing costs down and offer flexibility in propulsion choices for future US fighters.
A potential AETP development effort for either P&W’s or GE’s AETD designs, or both, would be aimed particularly at developing and creating the conditions for volume production of adaptive-cycle engines. These would be designed specifically to power the sixth-generation aircraft beyond the F-35 meeting, respectively, the US Air Force’s Next Generation Air Dominance (NGAD) and the US Navy’s FA-XX project requirements.

Decision Time Nears

Jimmy Kenyon, Pratt & Whitney’s Director of Advanced Programmes and Technologies told AIR International: “Unlike any other time in history, when F135 SDD [system development and demonstration] ends at the end of 2016, there will be no [new] US fighter engine in development.” He said “the increased urgency of [the] NGAD [requirement] creates an opportunity” for Congress to act swiftly to ensure the US leads future fighter-engine design by approving the transition of today’s AETD projects into AETP efforts, leading to full production of sixth-generation adaptive- cycle engines. Kenyon declared that AETD/AETP is “integral” to that future-fighter engine effort: “If you take and mature it, it is timed pretty well for when NGAD [development] would start in earnest. The other part of it is that [the adaptive-cycle engine] is a fundamental new technology and is a game-changer.
I can inform and be informed by those requirements, so I can develop the right technology for the right application for the right time.”
He added: “It is sort of linked to the Aerospace Innovation Initiative”. This was announced by US Under Secretary of Defense for Acquisition, Technology and Logistics Frank Kendall on January 28. It is a funding strategy designed to protect the US industrial base from losing its global lead in military aerospace design and technology as a result of sequestration cuts. The initiative, which would initially be led by the Defense Advanced Research Projects Agency but would also involve the air force and navy, would concentrate on developing prototypes for the next generation of US fighter aircraft – manned, unmanned or both.

Beyond the F-35

Within this supporting funding structure, any manufacturers selected to develop adaptive-cycle designs into one or more production-capable engines would be “taking technology and being influenced by those next-generation-of-aircraft needs”, said Kenyon. At present, P&W and GE Aviation “can only really use the F-35 as an example” of a current-production, advanced fighter to inform their future fighter-engine designs. This is why, in the absence of an airframe- specific requirement from the AFRL other than that the manufacturers’ AETD designs should provide 10% higher maximum thrust than the F135 but be 25% more fuel-efficient, both companies chose to base their AETD designs on the existing F-35 installation. The F-35’s existing F135 powerplant is the world’s most powerful fighter engine, but its installation within the F-35 is a particularly complex tight squeeze due to the designed- by-committee constraints and requirements the F-35 airframe has had to satisfy. Any adaptive-cycle engine that can fit into exactly the same dimensions as the F135 (or the F136, GE’s alternative F-35 engine, which Congress killed off despite that engine’s promise) will require exquisite skill in its design, major technological advances to provide its performance improvements, and superb engineering to pack its complexity into the F-35 airframe.

Contrastingly, “having an aircraft optimised [for a future engine developed in parallel with the airframe] would be sort of a holy grail,” remarked Mark Buongiorno, Pratt & Whitney’s Vice President of the F135 Engine Program: there wouldn’t be anything like as many adaptive-cycle engine design constraints for a new airframe as there would be for one designed for the F-35.

The Need for
Adaptive-Cycle Engines


But why are the USAF and US Navy so excited about adaptive-cycle engines? They see these propulsion systems as the only way technologically can develop turbofan engines that can meet the thrust, cooling, fuel-efficiency and electrical power- generation requirements – one megawatt or more, for directed-energy weapons and electronic countermeasure needs – that
the sixth generation of USAF and US Navy fighters will demand. Military operators would use the 25% fuel- efficiency improvement and 10% additional thrust (compared with the F135) the AFRL is demanding from the manufacturers’ AETD designs in various different ways.

Although much of a typical mission consists of target-area ingress and egress in cruise configuration, in the target area itself the pilot may require high power from the aircraft. Here, the 10% thrust improvement would help ensure rapid acceleration and improved manoeuvring capability. In a sixth-generation aircraft the 25% fuel-efficiency improvement would probably translate into a 30%-35% increase in range over today’s fighters – a performance enhancement that could transform an air force’s basing and force-allocation decisions. Meanwhile, for flight- and combat-training missions, pilots could upload far less fuel and still spend the same amount of time in the air.

Providing the Benefits

Instead of relying on the two streams of air – core air and bypass air – that current- generation military and civil turbofans use, tomorrow’s fighter engines will also use a third stream of air passing outside the engine core and the main bypass duct to perform a variety of functions. To perform these functions, the third air stream will be capable of being modulated. This modulation will be controlled by variable-geometry features within the fan section and the extra, annular duct through which the third stream will flow. The additional functions and variable-geometry features will flexibly modify the way the engine’s fan section operates, creating what effectively will be a variety of different turbofan engine designs in one package. The third stream will provide a way to offer a smooth transition from a low-pressure-fan, high-bypass turbofan at one end of the fuel- efficiency/power curve to a high-pressure- fan, low-bypass turbofan at the other. At the high-pressure-fan end of the curve, the adaptive-cycle engine will act like a pure turbojet – pushing almost all the air entering the engine inlet through into the core, to be combusted and exhausted, providing high power for take-off and acceleration.

At the low-pressure-fan end of the curve, the third stream will turn the adaptive-cycle engine into a high-bypass turbofan offering high fuel efficiency. This will provide the future fighter with increased range and longer loiter time and will reduce its overall fuel burn.

Transitions through intermediate stages of fan pressure and bypass ratio will offer a range of operating states, any one of which will be automatically selected during a given phase of flight or manoeuvre to provide the engine with an optimal ratio of core air to bypass air. During supercruise, the duct carrying the third stream would be able to swallow and feed through the adaptive-cycle engine much or all of the inlet air that the core and bypass streams of today’s two-stream fighter turbofans can’t accept. In supercruise today this air gets pushed back out of the engine inlet, essentially being dumped overboard. This dumping creates a phenomenon known as spillage drag, which complicates and hampers a fighter’s ability to supercruise easily and fuel-efficiently.

The third, adaptive stream of air will also increase greatly the extent of cooling the engine can offer the airframe, to make sure the aircraft’s performance isn’t constrained in any area of its flight envelope by the airframe retaining too much heat. When this article was written in mid- April, the F-35 was known still to have an airframe heat-retention issue that prevented it from operating at sustained high subsonic speeds (within 20% of Mach 1) at low altitudes. While potentially solvable, this isn’t a problem that F-35 pilots or operators of future NGAD fighters would want to have during a mission.
Additionally, the third stream will provide a way to increase the electrical power requirement available from the engine when such an increase is needed.
Kenyon also noted that, “it would be very good for the efficiency of the engine if you could manage adaptively the very high transient temperatures behind the augmentor”. Yet another benefit is that the third stream will cool the hottest parts of the two-dimensional, non-axisymmetrical exhaust nozzles that future US fighters will use to mask their exhaust heat to improve their stealth qualities and missile-defence capabilities.

P&W’s AETD Project

At the time of writing, Pratt & Whitney was about to enter a two-to-three week preliminary design review (PDR) of its design with AFRL engineers and scientists, a passing grade from which was necessary for the company to be able to proceed with its planned additional AETD developments and demonstrations. (GE Aviation completed its PDR in the first half of March, the AFRL approving of GE’s AETD design work to date and allowing the manufacturer to proceed to its planned series of rig tests and demonstrations.) While P&W doesn’t intend to perform a compressor rig test of its AETD design, the company did have a “very successful first test of a three-stream, full-scale design in late 2013”, according to Kenyon, primarily to verify P&W’s tooling and design capabilities for the subsequent AETD research effort.
Assuming a successful completion of its PDR process, P&W will then manufacture hardware for the two big AETD tests it plans to conduct before the programme ends in the latter half of 2016. First will be a test of a full-scale “very high-efficiency core” that P&W has designed specifically for the AETD project. P&W’s testing will culminate next year with a demonstration of a full-scale, three-stream fan module “in a real-engine environment”, according to Kenyon.


P&W has ensured this demonstration will be authentic by purchasing internally one of its own F135 engines. The company will fit its three-stage, full-scale AETD fan on to the front of the core of this engine, which will retain the augmentor and exhaust nozzle. (GE’s AETD strategy is different: it is conducting a rig test of a full-scale compressor but plans to test only a sub- scale version of its AETD fan design, before doing a full core test.)

Potential Future
Developments


Although the AETD project seeks flexible variation of the fan pressure and bypass ratio of a turbofan fighter engine in order to alter its fuel efficiency, thrust, cooling and electrical power-generation capabilities, Kenyon sees no reason why future fighter engines shouldn’t be made adaptive in other ways as well. “There are ways of looking at taking the core and making it adaptive, as well as the fan,” he said. “It’s really pretty neat, when you look at it in that context. It’s all about air management, and where do I want to put that air in the [compression-combustion- exhaust] cycle.

“Beyond AETD, can [adaptive design] change? Yes, if there’s more funding. AETD opened up the [adaptive] world...[there could also be] an adaptive core, somewhere in five-ish years. If I know I have a propulsion system that needs to do a lot of stuff of a transient nature, that’s a big deal. Adaptive capability] changes the performance of the core in a number of different ways.” Here Kenyon is talking about the US Navy’s Variable Cycle Advanced Technology (VCAT) programme, in which P&W has been engaged as an industry partner since 2012. This nine-phase programme, still in an early stage of development, aims to create a suite of technologies which, Kenyon said, would be different from but in many ways complementary to the adaptive-fan technologies developed for AETD. Few details are available about VCAT, but it is concentrating on developing adaptive-cycle features for a future fighter-engine core. Asked if marrying VCAT technologies with those from the AETD programme would produce fuel-burn and thrust-increase benefits beyond those produced by an adaptive-fan engine alone, Kenyon said an engine design incorporating AETD and VCAT adaptive features would offer “substantially greater” benefits.

A Two-Pronged Approach

Kenyon and Buongiorno are sure the adaptive- cycle approach is the right one for the next generation of US fighter aircraft potentially entering production in the latter half of the 2020s or beyond. But they are by no means as sure it is necessary to re-engine the F-35 with a fully adaptive-cycle engine by the mid-2020s – a step for which some military strategists have argued, given the F-35’s known heat-retention problem and likely future increases in operators’ power-generation requirements. As the manufacturer of the F135, P&W has a vested interest in ensuring that its engine continues to be the sole-choice powerplant for the F-35 throughout the aircraft’s production life. Nevertheless, Kenyon and Buongiorno said many of the benefits an adaptive-cycle engine could provide for the F-35 could instead be provided by a lower-risk, two-stage F135 development strategy that P&W is calling its F135 Block Upgrade Plan.

Under this new strategy, which the company revealed on April 2, P&W would create a development plan for the F135 – much as it did for its enormously successful F100 engine, which has been in service for 40 years this year but will remain in production at least until late 2016. Today’s F100s are vastly different from early F100s in terms of their time-on-wing durability, their operational reliability and the maximum thrust they offer; P&W thinks F135 development will proceed similarly.Kenyon believes there are many parallels between the F100 and the F135 programmes: just like the F100, thousands of F135s will be built and it will see service for decades with a wide variety of air arms throughout the world. Now the end of the F135 SDD initial-capability phase is in sight, it behoves P&W to address a long-term development plan for the F135.
https://www.scribd.com/doc/269303020/AIR-US-NG
 

malipa

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It is an artists rendering of a F-35 and a B-2 inlet mix up. I don't think we will ever see an inlet on the top of a fighter aircraft.
 

malipa

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The reason you don't want an intake on top of your aircraft is when you enter a high angle of attack maneuver, you choke your engines....
 

sferrin

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malipa said:
The reason you don't want an intake on top of your aircraft is when you enter a high angle of attack maneuver, you choke your engines....
I'm well aware of why they're not ideal. But all designs are trade offs. A dorsal intake could conceivable earn it's way onboard.
 

Arjen

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sferrin said:
I'm well aware of why they're not ideal. But all designs are trade offs. A dorsal intake could conceivable earn it's way onboard.
http://www.airspacemag.com/military-aviation/century-series-wannabe-209334/?no-ist
Depending on who’s talking, the North American F-107A was either the best fighter the Air Force didn’t have the sense to buy, or a politically flawed loser from the outset.
[...]

In the 1950s, every service but the Boy Scouts seemed to want nuclear-strike capability. And not only were the Air Force, Navy, and Army all competing to deliver The Bomb, within the Air Force, both Strategic and Tactical Air Commands wanted nuclear bombers, whether they were strategic goliaths or small tactical fighter-bombers. So rather than a bomb bay, the -107 had a kind of belly pouch that could half-cradle a hydrogen bomb to drop at Mach 2 from altitude or deliver from an under-the-radar approach.

That’s why the intake was piggyback. A conventional nose inlet would have required an internal air duct that would interfere with the centerline weapons station. Wing-root intakes that bracketed the bomb might have worked, but North American thought the dorsal tunnel straight back to the engine was a neater solution. (Some have claimed that wind tunnel tests showed airflow around a nose intake would interfere with bomb release, but no such testing was ever done on an F-107A.)
 

sferrin

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Arjen said:
sferrin said:
I'm well aware of why they're not ideal. But all designs are trade offs. A dorsal intake could conceivable earn it's way onboard.
http://www.airspacemag.com/military-aviation/century-series-wannabe-209334/?no-ist
Depending on who’s talking, the North American F-107A was either the best fighter the Air Force didn’t have the sense to buy, or a politically flawed loser from the outset.
[...]

In the 1950s, every service but the Boy Scouts seemed to want nuclear-strike capability. And not only were the Air Force, Navy, and Army all competing to deliver The Bomb, within the Air Force, both Strategic and Tactical Air Commands wanted nuclear bombers, whether they were strategic goliaths or small tactical fighter-bombers. So rather than a bomb bay, the -107 had a kind of belly pouch that could half-cradle a hydrogen bomb to drop at Mach 2 from altitude or deliver from an under-the-radar approach.

That’s why the intake was piggyback. A conventional nose inlet would have required an internal air duct that would interfere with the centerline weapons station. Wing-root intakes that bracketed the bomb might have worked, but North American thought the dorsal tunnel straight back to the engine was a neater solution. (Some have claimed that wind tunnel tests showed airflow around a nose intake would interfere with bomb release, but no such testing was ever done on an F-107A.)
The F-105 had an actual internal bomb bay and it didn't need a dorsal intake. Also, why the F-107 had a dorsal intake is pretty much irrelevant to this discussion. The fact of the matter is it was a fighter aircraft with a dorsal intake. And it's failure was not due to the dorsal intake.
 

Ogami musashi

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to add to sferrin, saab gripen was close to be a dorsal intake fighter as a study (publicitly available) showed that under certain condition high AOA performance was as good if not better.


Plus the advent of integrated vortex generators and plasma flow control...things are not set in stone. fixed inlet for a mach 2 fighter were a no go 30 years ago...look at the raptor.
 
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