Because I'm bored out of my mind on labor day and I want to engage with you in good faith, I'm going to take the time to thoroughly entertain your conjectures. My purpose isn't convincing you per se. It's to make bare the inherent contradictions in your conjecturing for someone who might think they make sense.
The F-4 prototype hit Mach 2.5 and zoom climbed to 98,000 feet in 1959 the same year the XF108 was cancelled. The F-4 was flight testing for an entire year before the XF108 was cancelled. The USAF would have taken into account all existing aircraft in development and testing as part of the XF108 cancellation.
The USAF would have known exactly what the F-4B was capable of long before 1961.
1. The XF108 was cancelled in '59 and McNamara entered office in '61.
2. The XF108 was cancelled not because the air force looked at the navy fighter and went "<3.<3 wow". It was cancelled because nuclear bombers weren't the major threat anymore. ICBMs became a thing. The air force had little need for a fast and long ranged interceptor.
So by the time McNamara could have asked the air force to consolidate programs and consider the F-4, there were no longer any programs the USAF was "giving up". In fact, when the F-4 flew, the USAF was at a crossroads, transitioning from interceptors to tactical fighters. TFX was started in 1962 followed by the F-5 program and F-X that became the F-15.
The F-4, it's adoption was a right time right place (or person) deal rather than "hey the navy option looks good lets go with the navy option". It would appear that until McNamara opened his mouth, the USAF wasn't planning on dancing with the F-4. No programs were cancelled
because the air force thought the F-4 was good. The F-4 was chosen because the USAF was at the cross roads and it was good enough as the transitional fighter.
Okay, that's addressing the F-4. Before we compare those, lets first take a deeper dive into your conjectures. I've went back and retrieved some of your comments in addition to the timeline you gave, which forms the main thesis of your conjectures regarding both the nature, timeline, and the engines of what you thin F/A-XX is in relation to the F-47
My conclusion is the first XA102 design review in December 2023 was for the 50,000lb thrust class engine to power the larger Lockheed NGAD design. This was called the "battlecruiser" by members on here and was an aircraft with a MTOW well above 100,000 lb....
The second XA102 design review in February 2025 was for a scaled down version of the engine in the 35,000lb to 40,000lb thrust range to fit the smaller Boeing 6th gen design. This Boeing design was originally developed for the Navy F/A-XX program. The USAF selected it and called it the F-47. The USAF swapped from the larger Lockheed design to smaller Boeing design in July to September last year.
1) US Navy had internally selected the Boeing design in 2024 but was leaving the decision until the next presidency.
2) USAF NGAD program pause 12 month ago saw them seriously look at the US Navy design. Again a purchase decision was delayed until the next presidency.
3) Trump enters office and to everyones surprise the USAF quickly selected the US Navy design and named it F-47.
4) Now the US Navy needs to restructure contracts as a joint program. That's why we have quotes saying the Navy could not award the contract "as written".
5) Boeing did not plan to win both programs, develop two derivatives and produce at twice the production rate. This is the industry capacity issue.
6) It's a joke to think the US Industry capacity can only produce one 6th gen fighter design. But for Boeing to develop two derivatives and built at a rate of 50+ aircraft per year would definitely push them.
7) The US Navy just allocated funding for F/A-XX but Boeing can only catch so many billions being thrown at them.
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Let's start from the very very beginning.
This was called the "battlecruiser" by members on here and was an aircraft with a MTOW well above 100,000 lb.
...the smaller Boeing 6th gen design. This Boeing design was originally developed for the Navy F/A-XX program. The USAF selected it and called it the F-47. The USAF swapped from the larger Lockheed design to smaller Boeing design in July to September last year [2024].
Then later:
The post you quoted from me I used the words "F/A-XX design" and "NGAD design". I intentionally avoiding using terms such as "prototype" or "demonstrator" as for some people these terms have different meanings.
You say a lot of things about how the air force chose a navy design but you also intentionally do not differentiate between demonstrator and prototype. Throughout your comments you seem not to have separated the events and timeframes that are associated with each of these terms and often conflated things to just... match your narrative.
- Demonstrators demonstrate available and mature technological solutions to the goals solicited in an RFI. They may or may not have anything to do with the final design beyond being the basis for the central technologies used in the final design.
- Prototypes / EMD prototypes are actually related to and are the intermediate designs that lead to the final manufacturing design.
With veritable evidence and zero conjecturing, this is the rough timeline we know of:
- 2015 Aerospace Innovation Initiative begins
- 2016, AETP contract awarded to GE and PW.
- 2019-20 Demonstrators begin flying with Boeing first, and LM afterwards. NG may or may not have flown anything for F/A-XX. Boeing built a demonstrator for the navy. LM built one for the air force. That does not mean Boeing did not compete for the air force contract nor does it mean LM didn't compete for the navy contract. Confirming selections was not what the AII demonstrator program was trying to do.
- 2021 - 22: AETP XA-101 and XA-100 complete tests. NGAP awarded.
- Jun 2022: Kendall says NGAD tech is ready for EMD phase
- May 2023: USAF issues formal solicitation for what would become the F-47. AETP cancelled. If anything, this is where prototypes and designs start getting drawn up and pitched.
- Feb 2024: NGAP design milestone, XA102 and XA103 named.
- July 2024: NGAD paused for review.
- Nov 2024: Navy says they will not be doing ACE for F/A-XX. Second remark about a derivative type engine.
- Feb 2025: PW and GE pass NGAP design reviews and begins building engine prototypes.
- Mar 2025: NGAD awarded to Boeing. EMD prototyping formally gets underway. Kendall and Hunter interviewed, says announcement was not a surprise and agree Boeing was the forerunner.
You claim that the original choice was LM's battlestar idea and that relative to when you made your comment, the switch to Boeing's smaller naval fighter happened in 2024, during the design review I presume.
- You are conflating terms and events. Boeing built a naval demonstrator. As we've said before, the purpose of a demonstrator and vs a prototype is not up to interpretation. Boeing's was chosen because a demonstrator was intentionally designed to appeal to both branches. If two planes came from the same demonstrator, that means literally nothing at this point. If Boeing were competing for both AF and Navy contracts it would have had two different proposals already for both instead of a single design.
- Both Kendall and hunter agreed that Boeing's was the preferred, more revolutionary option. That doesn't necessarily mean more capable, but just more innovative. That Boeing was the preferred option had been said by Vago as early as 2023, just after the solicitation was issued and just before NGAD was paused for review in 2024. Even if we exclude Vago's comments, we don't know which vendor was preferred or that any switch in preference occurred. We also have no evidence as to when or why it occurred. This also means that we can't verify which proposal was the 300 million option and which wasn't.
To conclude this section, I can agree that Vago might be wrong and they switched vendors during the review and Boeing became the preferred option during the review. What this doesn't mean is that the chosen design had anything to do with the navy beyond originating from the same demonstrator.
USAF NGAD program pause 12 month ago saw them seriously look at the US Navy design.
Lets first consider why the air force was pausing the program and what the investigation sought to resolve:
1.
Unit costs. Kendall's quote:
“We’re looking at the NGAD platform design concept to see if it’s the right concept… whether we can do something that’s less expensive and do some trade-offs there"
Kendall: the prior design from the Aerospace Innovation Initiative was “a very expensive concept. Scale matters, numbers matter, and so does time. We want to get something there quickly.”
2.
How to optimize NGAD around CCAs: Another quote + reported context from Kendell:
along with looking for ways to bring down costs, Kendall said the Air Force wants to ensure NGAD can take full advantage of CCAs as it is redesigned. He noted the CCA concept came along after the service had begun working to develop NGAD. + “Having something that’s optimized to work with CCAs is another consideration as we look at NGAD,” Kendall said.
3. Propulsion choices (adaptive engine cost/benefit): More of Kendall:
“A smaller, cheaper engine?” — Kendall said NGAD’s propulsion could be less complex/smaller to cut cost.
Firstly, where, if even in a single report, has F/A-XX been mentioned as an alternative? Nowhere. I could neither find any single person of any authority propose this nor any official reports indicating this. If a program like F/A-XX could be cancelled and announced to the public, I don't see why this can't be announced.
Every single time you say this, you have zero hard evidence backing this. You are just reading between the lines and drawing conclusions from cherry picked evidence.
Secondly and more importantly, How would F/A-XX address any of these problems? For the purpose of entertaining your points:
- We don't actually know whether F/A-XX would be smaller or lighter. You say that the air force considered a light fighter. Allvin said he did not rule out a low cost crewed fighter, which, yes, could mean a light fighter. F/A-XX may or may not be lighter or smaller. You reason for F/A-XX being smaller was that F/A-XX was sized around GE F110s and that an equivalent adaptive engine would allow for a smaller aircraft. Maybe, but this is in direct contradiction to the Navy's own statements regarding any ACE for F/A-XX. No one has ever said anything relating to F/A-XX's size and all you have regarding F/A-XX size is the super hornet mission profile and conjectures about possible engines.
- We don't know that F/A-XX would necessarily be cheaper either. If we exclude Vago's comments in 2023, the comments posted by joshjosh and I only indicated that Boeing's took a more revolutionary approach. LM took a conservative and evolutionary approach. Both achieved the objectives. What level of "exquisite" and "cost" they arrived at cannot at all be directly extrapolated without more evidence. If we take into account Vago's comments, then Boeing's offering was the 300 million one. If that was the naval option you speak of, then it also wouldn't at all help the price problem.
- Different mission requirements. F/A-XX is a dedicated strike fighter. F-47 is built for air superiority. From aerodynamics, to structural limits, to plan form design, an optimized air superiority fighter and an optimized strike fighter differ greatly from one another. Since the beginning, the requirement of the PCA portion of NGAD has been a dedicated air superiority platform. Since the beginning, F/A-XX was meant to be a dedicated strike fighter to replace the super hornets. It's hard to see how an F-18 could be modified kinematically match the F-15C for the air superiority role. It required air frame reinforcement, new engines, CFTs, and reduced kinematics to turn the F-15C into the F-15E and fulfill the role as a strike fighter and this was going from an air superiority fighter to a strike fighter - not the other way around
- F/A-XX derivative needs to fulfill the RFI better than a revised and downgraded version of the air force's own design in order for it to make sense to choose this to build a derivative with.
So to conclude this section, you have to extrapolate a lot and a lot of conclusions not backed by any evidence in order to believe F/A-XX could sufficiently cut costs, fulfill roles and have ACE engines jammed in (we'll get to this later as I've got a whole section for this). As of now, it suffices to say that F/A-XX in no way shape or form offers any immediate benefits that fulfill what the air force wants for its future fighter.
Trump enters office and to everyones surprise the USAF quickly selected the US Navy design and named it F-47.
Everyone? Kendall and Hunter, the two top civilians closest to the matter weren't surprised:
Q: But during that pause [of the NGAD program in 2024], did anything change that surprised you when the announcement was made [that Boeing had won the NGAD contract]? Did you have, for example, a preferred candidate and they chose a different one?
Kendall: To my knowledge, nothing significant changed. Andrew, do you agree?
Hunter: The only thing that was new to me was the nomenclature of F-47.
It was the people who put too much weight atop Boeing's mismanagement and lack of contracts for stealth fighters while ignoring Boeing's significant contributions to stealth and partnerships with DARPA that were surprised at this. Also note that not a single interviewee indicated that there was some kind of switch in preference, nor did they oppose Vago saying that Boeing was the preferred option all along. This may or may not imply that Boeing's option was infact the 300 million unit price option all along and that if any cost saving measures were undertaken, they were undertaken by modifying the Boeing's AF design rather than choosing some naval design Boeing had for the navy.
Given the statements from the two, It would seem that there was no last minute change nor did Trump or Musk do anything to force the change.
The only advanced engine was the XA100 and XA101. The XA100 engine first ran in December 2020. The larger Lockheed NGAD demonstrator most likely would have used the F135 or XA100
The smaller Boeing F/A-XX demonstrator had no advanced engine that would fit.
The top engine is the direct upgrade for the F-35.
The middle engine is the same large F-35 "common core" with slightly reduced bypass to suit the large supercruising Lockheed NGAD. This is the XA102 engine that had the design review in December 2023.
The lower engine is the smaller "scaled core" which can suit designs based around the F119 or the F110 engine. This is the second XA102 that finished design review in February 2025. As the Navy planned for F/A-XX to use an existing engine most likely the F110. This scaled core adaptive engine can now fit the F/A-XX design to cover the USAF NGAD requirement.
My conclusion is the first XA102 design review in December 2023 was for the 50,000lb thrust class engine to power the larger Lockheed NGAD design. This was called the "battlecruiser" by members on here and was an aircraft with a MTOW well above 100,000 lb....
The second XA102 design review in February 2025 was for a scaled down version of the engine in the 35,000lb to 40,000lb thrust range to fit the smaller Boeing 6th gen design. This Boeing design was originally developed for the Navy F/A-XX program. The USAF selected it and called it the F-47. The USAF swapped from the larger Lockheed design to smaller Boeing design in July to September last year.
The USAF is now funding the adaptive engine that is the correct size for the Navy. This eliminates the first reason.
Next, I want to specifically address the problems in your engine conjectures, as they underpin a large part of your argument and justification for the USAF choosing Boeing's F/A-XX design.
- Not sure why you think two proposals for the same contract would use two separate engines/sizes. Your reasoning is that the larger LM fighter required larger engines. Not a single person on this forum (except for maybe quellish with all the FOI docs he's got) knows how large the LM fighter was (and he says LM's fighter was different, not necessarily larger). Unless you have evidence that points to LM's option being large enough that it absolutely requires different engines, then this is again - dressing up evidence with conjecture and drawing ungrounded conclusions.
- VCE engines started with the AETP which was built to replace the F135 engine. NGAP started before the official solicitation for NGAD PCA was even released. The USAF diagram you point to as evidence shows AETP being the direct upgrade to the F-35 while the scaled common core of AETP was used to develop the smaller form factor NGAD engines. The scaled core could be applied to legacy platforms like the F-22/ F-15/ F-16 - not that it currently is going to be at all. Can it be applied to the F/A-XX if it fits the form/factor of the F110? Maybe. But it most certainly isn't happening right now.
- Might I also remind you that the USN explicitly rejected ACE in late 2024. There was chatter from GE's CEO about how moving forward with F/A-XX would also help development of ACE engines and that does lend some credence to maybe the Navy still considering ACE engines, but his comments could mean anything from additional funds from the navy to continue to research viability in a future engine replacement as well. This does not indicate that the Navy has actually changed its mind.
- It's not at all suprising that the same engine has undergone two design reviews. I don't know how you conclude what each review was for unless you have other evidence you refuse/can't disclose. There was never a second X102. There has and always been a single X102 engine attached to GE's NGAP engine. So I'll file this under the dressing up evidence folder again.
- In the same design reviews you quoted before, GE explicitly said the following:
2024:Data from this new round of testing, coupled with data from prior rounds, will directly inform and benefit the Next Generational Adaptive Propulsion (NGAP) effort underway by the U.S. Air force.
2025: As part of NGAP, GE Aerospace has a second adaptive engine in development, the XA102, which completed a major design review in December. The XA102 will now continue toward a prototype engine test
With the DDR now complete, GE Aerospace has been awarded the next contract phase to procure, assemble and test a XA102 full scale demonstrator engine...The XA100 engines completed multiple successful rounds of testing, maturing adaptive engine technologies. The XA102 engine represents the next evolution of propulsion
GE refers to both as separate engines, meaning that XA100 - 103 are four separate engines and from the timeline I wrote above, AETP and NGAP were being run in parallel, with AETP having started earlier. These are all "advanced engines". X100 and X101 were not the only advanced engines.
- There's zero direct or indirect evidence to suggest or imply the air force is funding ACE for the navy. I read and reread your comments about this and I can't find what evidence you cite for this. Instead, this seems to be logic filler you used to bridge the GE CEO's comments and justify the USAF picking the Boeing F/A-XX design.
Finally, lets consider a common design that can accomodate two different engines, two different mission sets along with two different requirements for aerodynamics, structural strength etc.
If Boeing develops both variants in series and starts with the easier USAF version it might enter service in only 3 years time and the Navy version in 6 years time. In this situation the Navy version timeline isn't changed but the USAF version arrives early. This is what they are trying to say.
Such a situation only applies if both services are effectively buying the same aircraft design from the same manufacturer as the manufacturer has fixed resources.
I'll admit - this one isn't impossible, but the odds are incredibly stacked against you.
- As we've said before, different structural requirements, planform designs are required to achieve specialized roles. You can absolutely design a fighter that can "do it all". You get a multi role fighter like the F-15E, F-18 or the F-35. That's not a fighter that can still be an air superiority PCA. Instead, having an air superiority fighter that can do strike as a secondary role and having a striker that can do some counter air as a secondary role still covers the majority of your situations while being very good at what both were intended for.
- Different engines. We've established that this point in time, the Navy has indicated it will not use ACE engines. Designing an airframe around two different intended engines isn't impossible, but again - its compromising, and complex not to mention entirely unreasonable when compounded with number 1. I could see this not be a problem if the Navy actually 180'd in the future, but at this point in time - you've provided no supporting evidence for this beyond conjecture.
- Timeline wise, this doesn't make sense. If this was a requirement, it would have been in the RFI. If this was Boeing's own idea and it was their intention to do it all along, then you would have heard Boeing, USAF and USN talk about this at some point. This isn't any more sensitive than anything other information released about the two aircraft. This being some recent thing during the development of both programs is even less likely, as a common air frame would be a fundamental factor to the overall design.
This is the one thing where the astounding silence of any media, government, or military reporting regarding this lends this theory very very little credence.
The other options are even more suboptimal:
- The USAF chose an under development F/A-XX design from Boeing. We've covered this already. It's got to be better than modifying USAF's own design and there's zero evidence to suggest this is the case.
- Trump forced the decision and the F-47 was "fast tracked" first so it could finish all the modifications while the F/A-XX just chugs along at its initial pace. This is batshit insane, but lets assume for a moment that this happened. Why didn't Kendall and Hunter say anything in the interview? Why did the air force stay so quiet about it? It's even worse than the first option because this would actually delay both fighters as the F/A-XX in this timeline would be the more mature design, but now that design has to wait and the now less mature derivative gets the front seat? It makes no political sense when numerous talking heads have said they want to get something flying fast.
Three simple explanations.
1) The USAF program was experiencing massive cost overruns due to features embedded into the design. They had no choice but to select the Navy design.
No. You again take evidence (probably the 300 million unit price figure because there's nothing else suggesting cost overruns of the program) and dress it up with your own ungrounded opinions. What makes you think that a program that has encountered significant cost overruns wouldn't have been exposed by a slimy journalist and become another outrage inducing news item for people to hate about? It there were cost overruns, we'd have heard about it by now.
2) The USAF during the NGAD pause evaluated both designs against the upcoming threat matrix. They determined the Navy design had far better value for money. They could say it could perform 95% of the missions at 50% of the cost.
How is a dedicated strike fighter and super hornet replacement able to perform 95% of the air to air job again? Refer to the same point from above. Unlike everyone else's conjectures, you've got not a single source of authority that has said F/A-XX does the PCA job well. Again - it doesn't just need to perform 95% of the air job. It needs to out perform a downgraded original USAF design. You just say these things without linking it to any hard evidence and without accounting for any opposing evidence explicitly saying or implying so.
3) The demonstrator for the USAF NGAD program was built by Lockheed. The design was fast tracked into service as a black program and is being built in the Skunk works. Obviously they can't make this public to the forum users on here.
Not impossible, but only in some people's wildest dreams that there exists such a monstrous black budget program.
This is exactly what I'm saying when I say that you take evidence (LM building the air force demonstrator), make inferences that are not at all fully supported by the known evidence, then come to conclusions so wild and so convoluted without offering any evidence for how you got there and without offering definitive and affirmative counter evidence for any contradictions that may be in the way.
So do us all a favor: If you want us to believe you, you have to reconcile the contradicting statements from officials without cherry picking, without conflating demonstrators and prototypes, without conflicting timelines, without changing stories and without dressing up what evidence you do cherrypick just to prove your point.
Lastly to finish this post, for your F4 analogy to stand, two assumptions must be made:
1. The air force was at a crossroads and has no currently viable design from either company and no path forward to make either design viable
2. The navy's offering is good enough for the air force to transition to where it wants to go.
The air force might well have been at a crossroads, but clearly there was a preference for a certain design over the other. To pick the navy's fighter would mean they had to give up their preferred design. This is not the same as being at the crossroads and having no immediate designs in the pipeline while the navy's fighter coincidentally fulfills the roles you envision for the future well enough.
Which brings us to the second point, which is that the navy's fighter with its derivative non ACE engines, lower stated operational range, and emphasis on strike focused mission set, does not at all coincide with what the USAF wants for its future fighter - contrary to the case of the F4, TFX, F5 etc.
A summary of contradictions you must reconcile:
- Did the USAF choose a navy fighter? Or did Trump forced them to? Or was the shared design built from the ground up to allow both variants to be built? Are the variants being pursued in parallel? in tandem? You've said all four in the past comments whenever convenient for you. None of these options share the same timeline either.
- Your story also seems to change whenever challenged. This time you added the black project thing probably due to the big loss item that LM is working on. If that's actually LM's NGAD proposal being put into service, how then do you reconcile LM's CEO wanting to do an F35 facelift with NGAD tech? Just apply it to your black project NGAD.
- The engine timeline relative to actual events. You say NGAP XA102 was scaled down for Boeing's F/A-XX design. Sure. Lets say a scale down occurred between demonstrator engine and prototype engine (in 2025) because I don't know enough about engine development to say whether this is possible when going from demonstrator to prototype. Why would this happen if the navy said they didn't want VCE engines barely 5 months before this?
- Why two design pitches for the same service would use two different sized engines? How would that work when NGAP, the intended propulsion for NGAD, has one set of prototype engines (XA102/3)? A scale down did indeed happen as the USAF described it. That was from AETP -> NGAP to create the XA102/3. The downscaling of XA102 engine itself was entirely extrapolation made by you while being backed by no source known to us.
- Navy repeatedly refusing the use of ACE engines for F/A-XX very recently - in direct contradiction with your conjecture that the navy is now going to use ACE, of which you've offered no evidence to refute or explain. Again - GE CEO's words indicate continued interest and possibility but doesn't immediately indicate the Navy has 180'd.
- The seemingly huge implications of your conjectures (program merging, ground up design of variants, air force paying for navy ACE engines, huge cost overruns, trump forcing decisions, black budget fighters) compared with the deafening silence of any affirmative and definitive reporting that corroborates your conclusions despite things far more sensitive or trivial have been reported upon.
I'm not going to outright dismiss your theories. Maybe we're all wrong and you are right, but with what evidence we have, with your own theories that keep changing, and with multiple contradictions by your own words, I'm not inclined to believe your conjecture. I've also said here and before that it makes sense to see external and planform similarities if both designs are from the same company. They can very well share the exact same technologies too, but that does not at all mean they are variants or "closely related" in any programmatic sense.
