Boeing F-47 NGAD - Speculation and Theories

[Scott Kenny]

There seems to be a fundamental misunderstanding of aircraft design process. Growth margin isn’t simply about a larger engine bay. The aircraft specifications should be a fallout of mission requirements and subsequent systems engineering efforts to define them, and that gets flowed down to the thrust needed for the required characteristics. It’s not simply thrust or an engine size for the sake of it.

On a practical level, while there is merit in having the engine bay sized to accept a slightly larger motors for future growth potential, enlarging it to F101-size is asinine. You run into serious issues with inlet and engine compatibility, such as buzz conditions.

F101s are only 4" bigger in diameter than F119s. F119s are noted for being a particularly slim engine for their thrust levels.

All descriptions and depictions of 3-stream engines are fat, due to the extra layer of bypass ducts needed for the middle stream.

 

[Scott Kenny]

300 is awfully tight for two squadrons of 12 on 12 carrier air wings (=288).

At a minimum they also need one Fleet Replacement Squadron, possibly two (F/A-18E/F has East Coast and West Coast FRS, F-35 has a Joint FRS), which ISTR tend to run big on the number of birds. Plus detachments at the strike fighter VXs (VX-9 and VX-23). Plus anywhere else strike-fighters end up, such as Naval Aviation Warfighting Development Center (formerly Top Gun and Strike-U).

Add in aircraft undergoing refits and modifications and I don't see 300 getting them more than 18 aircraft per carrier.

Yes, ~400 is probably a more reasonable total, once we count all the extras. FRSs, VXs, Blue Angels etc.

 

[bring_it_on]

It has been my view for some time that F-35 was the first effort for an ACE for largely political reasons, and that focusing first on a 45k thrust engine caused unnecessary delays on a scaled down version for F-47/NGAD, simply due to prioritization of resources of a very small and specialized part of the industrial base that has a scarce, fixed ability to do only so much at any given time.

AETP was set up about the same time as the Aerospace Innovation Initiative in Fiscal Year 2016. It was to transition technology developed via previous efforts into flight weight prototype engines with as a direct upgrade for the F-35 and a scaled common core that would allow for an engine in the NGAD thrust class once that program had matured propulsion requirements for it. You have to know what you actually want before you can ask teams to begin designing and developing it. And it looks like they did do this as soon as they figured it out.

AETP was originally slated to run through Fiscal Year 2021 (five year program) with, what they hoped, transition of work to one or more engine EMD programs. Had things gone to plan, AETP would have transitioned to two EMD programs. The FAER effort to re-engine the F-35A and NGAP to develop an NGAD engine. FAER, if sanctioned, was looking to enter low rate production around FY 2028-2029 timeframe (probably an optimistic timeframe).

We know from program details shared by the USAF years ago that AETP contract awarded to each of the two performers had options built in for NGAP which would be scaling technologies to a NGAD sized engine. These options were clearly put there so that the contractors could begin workin on a second engine design as soon as requirements for it were finalized. The said options were exercised in FY 2018 or roughly 2 years after the AETP launched. Therefore, for four of the six or so years the teams were funded via the AETP contract, they were working on both efforts in parallel. Air Force had to strip out NGAP funding for visibility after Congress kept pushing back on the budgeted dollars for AETP IIRC but NGAP development was very much there..just less visible than the two F-35A sized engines that they tested to round out the initial program.

All of this information is right here on this forum in the relevant threads.

 

[Training_Dummy]

Thanks for the comprehensive post - you’re right a lot of this has been posted and I do constantly reread the relevant threads. Thanks for taking the time to put it all together - I’m certain I’m not the only one here who benefits, but if i am, that just makes me more thankful.

 

[bring_it_on]

Another thing worth (re) highlighting to close the loop on the topic of whether they could have simply picked an engine size, thrust class and asked P&W and GE to build engines in advance of actual program requirements (a path they avoided with AETD and AETP by instead focusing on known F-35A engine requirements).

From the 2022 IDIQ awards to airframe and propulsion designers for integrating adaptive engines into NGAD

“Any propulsion system has to be built and designed for the specific platform on which it’s operating. And it’s especially true for these adaptive engine systems,” said Mark J. Lewis, executive director of the National Defense Industrial Association’s Emerging Technologies Institute and former chief scientist of the Air Force, in an interview. “So you’d want to develop the engine hand in hand with an airframe. It’s going to be more difficult to make an adaptive engine a sort of a plug-and-play system. Not impossible.”

Lewis was quick to note that his views were speculative. But some of the technological advances coming with the adaptive engines could require fighters built to take full advantage of them, Lewis said. In particular, adaptive engines can transition between modes optimized for thrust and for range.

“Today if you design an airplane, you start deciding, what’s most important. Does it have to have maximum acceleration at this point in its performance? Does it have to be able to fly for a maximum range? And those two requirements, for example, could be at odds with each other,” Lewis said. “With an adaptive engine, you might be able to get the best of both worlds. And so your airframe might reflect that.”

Airplane-Makers Win Contracts as Part of Next-Gen Engine Prototyping Phase | Air & Space Forces Magazine

The Air Force picked five companies to work on the prototyping phase of Next Generation Adaptive Propulsion, which will make engines for NGAD.

www.airandspaceforces.com

 

[EmoBirb]

Yes, ~400 is probably a more reasonable total

Is that reasonable from a financial point though? Given the Navy is notoriously broke and has dozens of other high profile programs going on?

That might be more for the F/A-XX thread though

 

[icyplanetnhc (Steve)]

F101s are only 4" bigger in diameter than F119s. F119s are noted for being a particularly slim engine for their thrust levels.

All descriptions and depictions of 3-stream engines are fat, due to the extra layer of bypass ducts needed for the middle stream.

The air vehicle and engine integration efforts, including engine bay sizing, inlet compatibility requirements, etc., will be designed around the XA102 and XA103. If an interim engine like an F119 variant is used for initial flight testing, then the interim engine will be adapted with minimal changes to the airframe itself (if done correctly). Invoking the F101, especially as an arbitrary form factor that the air vehicle should be designed to accommodate, makes no sense.

 

[Scott Kenny]

The air vehicle and engine integration efforts, including engine bay sizing, inlet compatibility requirements, etc., will be designed around the XA102 and XA103. If an interim engine like an F119 variant is used for initial flight testing, then the interim engine will be adapted with minimal changes to the airframe itself (if done correctly). Invoking the F101, especially as an arbitrary form factor that the air vehicle should be designed to accommodate, makes no sense.

I am saying that every indication is that the A102/A103 are fatter in diameter than F119s, despite being in the same rough thrust class.

So it would be better if the interim/early test engine for basic flight characteristics/laws was chosen to be the same diameter as the A102/A103.

 

[Scott Kenny]

Is that reasonable from a financial point though? Given the Navy is notoriously broke and has dozens of other high profile programs going on?

That might be more for the F/A-XX thread though

That's basically 1:1 replacement of Super Bugs. Just how quickly the USN adopts CCAs, and particularly strike CCAs, will control how many FAXX they need operationally.

IMO, the question is not "can we afford ~400x FAXX" but "can we afford NOT BUYING ~400x FAXX"

In the 1970s, the USN bought a fighter that was equivalently expensive as the FAXX or F-47 are expected to be, and was actually more expensive than the F22 was (once adjusted for inflation).

 

[Ozair]

I am saying that every indication is that the A102/A103 are fatter in diameter than F119s, despite being in the same rough thrust class.

So it would be better if the interim/early test engine for basic flight characteristics/laws was chosen to be the same diameter as the A102/A103.

That is a change by you... The initial discussion was a same size or smaller engine than the XA102/103 and you then suggested a larger engine. If the 102/103 are fatter then the interim engine would be the best possible fit, or smaller, to ensure no airframe changes are required.

I feel like you are finally understanding what has been suggested...

That's basically 1:1 replacement of Super Bugs. Just how quickly the USN adopts CCAs, and particularly strike CCAs, will control how many FAXX they need operationally.

IMO, the question is not "can we afford ~400x FAXX" but "can we afford NOT BUYING ~400x FAXX"

The other side of that question is whether it is worth investing in F/A-XX to that amount. We already know it won't have the range many of us were anticipating, perhaps it won't live up to expectations or tactically it will be passed by as other systems evolve.

In the 1970s, the USN bought a fighter that was equivalently expensive as the FAXX or F-47 are expected to be, and was actually more expensive than the F22 was (once adjusted for inflation).

The USN also had more carriers in the 1970s, approximately 15 if you count retirements and new builds, and had a healthy production base for surface and undersea warships. It does not have that today, hence why the budget pumps an additional 30+ billion into shipping.

 

[icyplanetnhc (Steve)]

I am saying that every indication is that the A102/A103 are fatter in diameter than F119s, despite being in the same rough thrust class.

So it would be better if the interim/early test engine for basic flight characteristics/laws was chosen to be the same diameter as the A102/A103.

I don’t quite know how you’re reaching the conclusion that the XA102 or XA103 will be comparable in size to the F101.

The 45,000 lbf thrust class XA100 and XA101 fits into the ~48" diameter engine bay of the F-35A. The XA102 and XA103 are smaller engines at 35,000-40,000 lbf thrust class. The F119 itself is not actually slim at all, but even so it’s nowhere near an F101 in terms of diameter. The F119's large radial projection comes from its two-dimensional thrust vectoring nozzles, while the fan diameter is considerably smaller than the F101, but larger than the F110.

All this is besides the point, because you seem to be ignoring that the F-47's engine bay will be sized around the XA102 and XA103, and the F101 would be completely unsuitable as an interim fighter engine in any case.

 

[dark sidius]

Allvin to Congress: USAF Will Have More Control of F-47 Fighter

Air Force chief of staff Gen. David Allvin said the F-47 will be quick to upgrade, and share mission systems with the autonomous CCA fleet.

www.airandspaceforces.com

 

[quellish]

Allvin to Congress: USAF Will Have More Control of F-47 Fighter

Air Force chief of staff Gen. David Allvin said the F-47 will be quick to upgrade, and share mission systems with the autonomous CCA fleet.

www.airandspaceforces.com

The actual hearing is here:

Open/Closed: To receive testimony on the posture of the Department of the Air Force in review of the Defense Authorization Request for Fiscal Year 2026 and the Future Years Defense Program | United States Senate Committee on Armed Services

Full Committee Hearing on May 20, 2025 at 5:30 AM

www.armed-services.senate.gov

Here is what was actually said. Again, I had the video transcribed at my own expense (the video subtitles were poorly formatted):

[00:45:17] Chairman: Okay. Um, now, um, General Alvin, let's talk about the f-47 and let's compare it to the development of the F-35. Um, there I understand there is a, um, a completely new acquisition approach. Don't take the full three minutes I have left. But what's what's the difference there? And how is this going to affect the taxpayer and the warfighter and national security?

[00:45:48] General Allvin: Thank you chairman. I'll go as fast as I can because I could go on for about an hour. The primary difference is that we are we now have more of control over the project as it moves forward. We have insourced more. We have more of the ownership of the the tech base. We are guided a government reference architecture. So we own the mission systems and so others can come in and play. But we own the development, the upgrade and so the upgrades can come at the speed of software, not hardware can come at the speed of our engineers understanding how fast to advance versus dealing with the contractor and paying the extra cost.

[00:46:24] Chairman: All right, sir, this is a major change in approach. Is it not.

[00:46:27] General Allvin: 100%.

[00:46:28] Chairman: Chairman, how is it going to affect the taxpayer? How is it going to affect the timeliness of this project?

[00:46:35] General Allvin: Chairman, I think we're going to have some conversations about F-35 and how we don't want to repeat that. So it is going to affect the taxpayer. My sense is that we're going to be able to be more agile. And as more disruptive technology comes into play, to be able to develop more advanced systems, we'll be able to more rapidly integrate them not only into the F-47, but into those two collaborative combat aircraft, the YFQ-42 and the YFQ-44 that are currently under prototype. They're all going to be under the same mission systems architecture. So we won't just be upgrading one platform, we'll be upgrading a system. And so the American taxpayer will get more combat capability out of their money, out of their money.

And - again - they are talking about how the NGAD FoS is pursuing a completely different acquisition paradigm than in the past. You might even call it... a "digital century series".

 

[Josh_TN]

The actual hearing is here:

Open/Closed: To receive testimony on the posture of the Department of the Air Force in review of the Defense Authorization Request for Fiscal Year 2026 and the Future Years Defense Program | United States Senate Committee on Armed Services

Full Committee Hearing on May 20, 2025 at 5:30 AM

www.armed-services.senate.gov

Here is what was actually said. Again, I had the video transcribed at my own expense (the video subtitles were poorly formatted):



And - again - they are talking about how the NGAD FoS is pursuing a completely different acquisition paradigm than in the past. You might even call it... a "digital century series".

But it seems less like entirely new manned aircraft would be constructed and more like 3rd party software, or potentially hardware, systems will be updated. That is still new and beneficial, but it seems likely the base aircraft remains the same and the entire run is still built by Boeing.

 

[quellish]

But it seems less like entirely new manned aircraft would be constructed and more like 3rd party software, or potentially hardware, systems will be updated. That is still new and beneficial, but it seems likely the base aircraft remains the same and the entire run is still built by Boeing.

Unlike past programs, here the government owns the design of the aircraft and the systems of the aircraft are part of a government owned architecture. This means that at any time the government can re-compete the execution (or changes to) the design. The intent is to re-compete often.

Boeing has won a contract for, let's say, round 1 of production. Boeing designed the aircraft, but the government now owns the design. The government can at some point compete round 2 - let's say it's aircraft tail numbers 100-150. Lockheed, Andruil, etc. can then propose how they will build those aircraft. And those aircraft could be basically the same as round 1, or they could be very different. For example, round 2 might have significant design changes to meet new threats or to be used in new geographic areas.

This applies to the whole aircraft as well as individual subsystems.

This is something it seems a lot of people have difficulty wrapping their heads around. For example, I have seen comments in the CCA threads that seem to indicate that some people believe that the two current CCA Increment 1 vendors are competing for a "winner takes all" contract. This is not the case - "winner takes all" is basically dead with this new approach.

 

[red admiral]

Ah the Soviet approach to aircraft design and manufacture... with a few more competitive aspects thrown in

It's going to be interesting to see whether any separate companies will be successful in competing for follow on orders. Learner curve effects means it's going to be incredibly difficult to compete on cost with an existing hot production facility/team. Then if the different companies are building the same aircraft differently then do you also need different Support and Maintenance? We'll see what happens.

 

[Josh_TN]

Unlike past programs, here the government owns the design of the aircraft and the systems of the aircraft are part of a government owned architecture. This means that at any time the government can re-compete the execution (or changes to) the design. The intent is to re-compete often.

Boeing has won a contract for, let's say, round 1 of production. Boeing designed the aircraft, but the government now owns the design. The government can at some point compete round 2 - let's say it's aircraft tail numbers 100-150. Lockheed, Andruil, etc. can then propose how they will build those aircraft. And those aircraft could be basically the same as round 1, or they could be very different. For example, round 2 might have significant design changes to meet new threats or to be used in new geographic areas.

This applies to the whole aircraft as well as individual subsystems.

This is something it seems a lot of people have difficulty wrapping their heads around. For example, I have seen comments in the CCA threads that seem to indicate that some people believe that the two current CCA Increment 1 vendors are competing for a "winner takes all" contract. This is not the case - "winner takes all" is basically dead with this new approach.

That approach makes sense for the CCAs, but I question if it is truly viable on a vastly more expensive manned platform. That is a maintenance nightmare. CCAs can at least be discarded or even just stored as a disposable store for high risk use; a manned platform needs constant training and maintenance.

I still think Boeing will end up building all the airframes; I just think the upgrade path will be far more fluid than F-35s incredibly bottlenecked block upgrades. Even that would be a great accomplishment. But you have more access and background information than I do, so perhaps we will be seeing multiple aircraft manufacturers.

 

[F119Doctor]

Actually, in most government funded development programs, the government owns the intellectual property, with the exception of any proprietary parts or processes provided by the contractor.

The F-35 development was the outlier, with Lockheed retaining much of the IP, especially for the support systems.

 

[quellish]

That approach makes sense for the CCAs, but I question if it is truly viable on a vastly more expensive manned platform. That is a maintenance nightmare. CCAs can at least be discarded or even just stored as a disposable store for high risk use; a manned platform needs constant training and maintenance.

Yes interchangeable parts are a maintenance nightmare.

But you have more access and background information than I do, so perhaps we will be seeing multiple aircraft manufacturers.

I have the same access anyone else does, including you.

I go out and find public information and verify it rather than waiting for someone to present it to me

 

[Josh_TN]

Yes interchangeable parts are a maintenance nightmare.



I have the same access anyone else does, including you.

I go out and find public information and verify it rather than waiting for someone to present it to me

If the parts are truly interchangeable - why switch airframe manufacturers? What is being upgraded? I can see system upgrades from third parties; I find a whole aircraft from alternative contractors hard to believe.

Fine, you have more free time then I do.

 

[Ozair]

If the parts are truly interchangeable - why switch airframe manufacturers? What is being upgraded? I can see system upgrades from third parties; I find a whole aircraft from alternative contractors hard to believe.

I agree with you, I am highly skeptical that this will work out. Boeing has invested billions in a manufacturing facility with the intent to build and deliver this aircraft. It is highly unlikely that other potential manufacturers will be able to establish an F-47 production line without significant Govt assistance. Unless that assistance is directly tied to increasing a production rate it makes little sense to spread that cost amongst multiple vendors.

Upgrade and sustainment of the aircraft is a different story and could easily be farmed out to the lowest bidder.

 

[Josh_TN]

Upgrade and sustainment of the aircraft is a different story and could easily be farmed out to the lowest bidder.

…and I think there is huge value to this that I am not trying to belittle.

But the century series, and from what I thought I understood about the digital century series, involved short term airframes that were put out to pasture in favor of totally new airframes. I am skeptical that model can work today with the expense of modern components and the levels of integration necessary for a modern fighter - you’re throwing too much away.

And what’s more, the threat of replacement by total automation will be bearing down on any manned U.S. fighter program by the end of the decade, whether it’s a good idea or not.

 

[Ozair]

…and I think there is huge value to this that I am not trying to belittle.

Not taken that way at all.

But the century series, and from what I thought I understood about the digital century series, involved short term airframes that were put out to pasture in favor of totally new airframes. I am skeptical that model can work today with the expense of modern components and the levels of integration necessary for a modern fighter - you’re throwing too much away.

If you consider the long term lifecycle of a fighter jet in some cases the cost to mid life upgrade can approach the initial acquisition cost so I see what they are trying to do. Also whether you have to engineer the aircraft for an 8000 flight hour life and instead look for 2000 hours. That may save some costs and potentially reduce inspection and depot time.

Question is what happens to the radars, engines and other systems that should be able to operate for significantly longer than the airframe? Does the USAF pull an XA102 out of a retiring airframe and send it back to Boeing, or the current lowest volume bidder to win the build work, to incorporate into the newest airframe off the line. Same with the radar and the IRST and the datalink systems etc., all of which should be able to remain reasonably static but be software upgraded to a new standard.

Lots of to be identified issues though. A couple of thoughts

• You would think build times would have to drastically reduce to accommodate a shorter life span, I don't think going forward we can plan on near 2 year build times for aircraft from long lead items to handover.
• If you build the aircraft for only 2k hours and retire it but need to pull it out of the boneyard because a conflict means you need more aircraft can the airframe even be brought back into service?

And what’s more, the threat of replacement by total automation will be bearing down on any manned U.S. fighter program by the end of the decade, whether it’s a good idea or not.

No doubt although I think the USAF won't be the first to move to an all unmanned fleet. I'd suggest smaller air forces are more likely to make that change before the USAF for cost and capability reasons but even then I cannot see things changing until the current 5th gen platforms approach their end of useful life.

 

[Josh_TN]

I was thinking more Congress being like “why are we pay for a new generation F-47 when we could save money by automating?”. I just think the iterative process for manned fighters is a hard sell in terms of total aircraft. I think the basic airframe and engine has to be consistent, or you could have PW and GE make alternate engines if you want, but a ground up new airframe from a new manufacturer seems like it would be hard to pay for, integrate, and justify.

Being able to yank the processors, radars, and other sensors, and swap for the other engine manufacturer (realistically only two) has vast benefits and I am glad they are approaching contractors with the idea that DoD owns the IP. I just think Boeing is always going to be the system integrator at minimum, and I cannot imagine the airframe it’s SWAPC changes significantly.

 

[Scott Kenny]

I feel like you are finally understanding what has been suggested...

Then we have successfully talked past each other for the last several days.

The USN also had more carriers in the 1970s, approximately 15 if you count retirements and new builds, and had a healthy production base for surface and undersea warships. It does not have that today, hence why the budget pumps an additional 30+ billion into shipping.

The point was that the USN was perfectly willing to buy fighters that were screamingly expensive back then, in massive numbers, because there was an operational need for them.

All this is besides the point, because you seem to be ignoring that the F-47's engine bay will be sized around the XA102 and XA103,

I'm expecting the XA102/XA103 diameters to grow over what they're currently expecting.

and the F101 would be completely unsuitable as an interim fighter engine in any case.

Yes, it would be a very poor fighter engine. It would be adequate for initial flight testing, however.

 

[Ozair]

The point was that the USN was perfectly willing to buy fighters that were screamingly expensive back then, in massive numbers, because there was an operational need for them.

More and more people are talking about the lack of an operational need or more succinctly the USN's inability to explain that need and how F/A-XX fulfils it.

I'm expecting the XA102/XA103 diameters to grow over what they're currently expecting.

Both engines have passed DDR so I expect there won't be much in the way of outer changes especially to the diameter. https://www.airandspaceforces.com/advanced-fighter-engines-pass-design-review/

 

[Reddington777]

More and more people are talking about the lack of an operational need or more succinctly the USN's inability to explain that need and how F/A-XX fulfils it.

I thought they were pretty clearly explained that they were replacing hornets...

Its probably a good idea to have something with more range and greater stealth than F-35s. F-47s have limited basing options and rely on tankers. F/A-XX is the multirole that'll tank off MQ-25s, do strikes and fleet air defense with greater range and survivability.

 

[VTOLicious]

Speaking of engine size...

Fan Diameter:
F100: 34.8"
F119: 36"
F135: 43"
AETP: 46"

 

[Scott Kenny]

More and more people are talking about the lack of an operational need or more succinctly the USN's inability to explain that need and how F/A-XX fulfils it.

Then those people have not been paying attention.

 

[Scott Kenny]

Speaking of engine size...

Fan Diameter:
F100: 34.8"
F119: 36"
F135: 43"
AETP: 46"

10" bigger fan diameter than F119. 3" bigger fan than F135.

So yeah, I suspect that the existing engine closest in external dimensions to the XA102/103 is still the F101.

 

[VTOLicious]

10" bigger fan diameter than F119. 3" bigger fan than F135.

So yeah, I suspect that the existing engine closest in external dimensions to the XA102/103 is still the F101.

Do you happen to know what's the fan diameter of the F101? ...or XA102/103?

 

[icyplanetnhc (Steve)]

Speaking of engine size...

Fan Diameter:
F100: 34.8"
F119: 36"
F135: 43"
AETP: 46"

That figure for the F119 is not correct, and I'll leave it at that.

10" bigger fan diameter than F119. 3" bigger fan than F135.

So yeah, I suspect that the existing engine closest in external dimensions to the XA102/103 is still the F101.

How would the XA102 and XA103, being a smaller engine than the XA100 and XA101 with a lower thrust class, be similar in size to the larger F101?

 

[VTOLicious]

That figure for the F119 is not correct, and I'll leave it at that.

We've discussed this before, and I've presented my conclusion... https://www.secretprojects.co.uk/threads/lockheed-martin-f-22-raptor.4505/post-738550

If you have evidence that shows otherwise, please share it with us!

 

[Forest Green]

Allvin: Air Force owns more tech on F-47, dodging F-35 mistake

Air Force officials regret not getting data rights to the F-35, which has slowed repairs, and promised not to make the same mistake on the F-47.

www.defensenews.com

 

[Scott Kenny]

How would the XA102 and XA103, being a smaller engine than the XA100 and XA101 with a lower thrust class, be similar in size to the larger F101?

F101 is a 30,000lb thrust engine, with a high bypass ratio for a military engine. So it's in roughly the right thrust class for swapping with the XA102/103.

XA102/103 are going to have a larger diameter than F119, by 1) having a larger diameter fan, and 2) by needing a larger diameter for space for the 3rd air stream to flow. And 2 seems to be the driving factor in case size.

@VTOLicious fan size data suggests that the XA102/103 are going to be ~14.5% larger area than F119, assuming that 3stream tech scales linearly. I don't have enough engine design knowledge to know if that's true, but it's usually good for initial assumptions.

The F119 is roughly 48" in external diameter, ignoring the 2D tail feathers 50" square box. 48*1.145=55"

And the F101 is 55" in diameter.

 

[icyplanetnhc (Steve)]

If you have evidence that shows otherwise, please share it with us!

No, I can't share controlled information.

It seems like some here are trying to insist on certain size parameters for the sake of it. That's their own prerogative then, I suppose.

 

[Sferrin]

We've discussed this before, and I've presented my conclusion... https://www.secretprojects.co.uk/threads/lockheed-martin-f-22-raptor.4505/post-738550

If you have evidence that shows otherwise, please share it with us!

Specifications (F119-PW-100)​

YF119 fanYF119-PW-100L thrust vectoring nozzle, designed for the YF-22
Data from Aronstein & Hirschberg,[8][5] Pratt & Whitney,[19] RAND,[9] Aviation Week,[20] USAF TO-00-85-20.[21][22]

General characteristics​

• Type: Twin-spool, axial-flow augmented turbofan
• Length: 196 in (497.8 cm)[N 3]
• Diameter: Approx. 40 in (100 cm) inlet, 48 in (120 cm) overall, 50 in (130 cm) maximum

 

[quellish]

Then those people have not been paying attention.

That’s becoming a very common theme on this thread, the lack of paying attention

 

[VTOLicious]

No, I can't share controlled information.
It seems like some here are trying to insist on certain size parameters for the sake of it. That's their own prerogative then, I suppose.

I respect that and don't insist on my opinion. It's the result of my conclusion, which I linked above.
Wikipedia states "Diameter: Approx. 40 in (100 cm) inlet". This can mean the outer or the inner diameter of the inlet (fan diameter). I'm always talking about fan diameter.

 

[GTX]

Discussion re some of the challenges with the F-47:

View: https://www.youtube.com/watch?v=vMBYpOIVWxg