The next jet: F-X & F/A-XX

1. F-15 was designed in the late 60s and the basic platform was conceived in 66 or 67 - not sure about selection. How many Thuds and Phantoms had been lost to Migs by that time period? It was designed around lessons learned from F-111.

2. The mighty Tomcat was designed solely around lessons learned from the F-111.

1. The F-111 contributed approximately 0.00% to the development of the F-15.

2. The Tomcat was influenced by the need to deal with the Foxbat and bomber-launched antiship missiles as well as have better air combat performance. The only "lesson" from the F-111B was "don't be that fat".

I remember the publicity and buzz around the F-15's birth at the time and it was pointed squarely at the Mig-25 Foxbat to be able to reach, intercept and shoot it down. Not once in all that time did anyone say in public we have to design a more maneuverable aircraft than Mig-21 because of Vietnam experience.

https://en.wikipedia.org/wiki/McDonnell ... ly_studies

The F-15 can trace its origins to the early Vietnam War
Through this period, studies of combat over Vietnam were producing worrying results. Theory had stressed long-range combat using missiles and optimized aircraft for this role. The result was highly loaded aircraft with large radar and excellent speed, but limited maneuverability and often lacking a gun. The canonical example was the McDonnell Douglas F-4 Phantom II, used by the USAF, USN, and U.S. Marine Corps to provide air superiority over Vietnam, the only fighter with enough power, range, and maneuverability to be given the primary task of dealing with the threat of Soviet fighters while flying with visual engagement rules.


Both Headquarters USAF and the TAC continued to call for a multipurpose aircraft, while both Disosway and Air Chief of Staff Bruce K. Holloway pressed for a pure air-superiority design that would be able to meet the expected performance of the MiG-25.

In September 1968, a request for proposals was released to major aerospace companies. These requirements called for single-seat fighter having a maximum take-off weight of 40,000 pounds (18,000 kg) for the air-to-air role with a maximum speed of Mach 2.5 and a thrust-to-weight ratio of nearly 1:1 at mission weight

Not only was combat studies from Vietnam the primary contributing factor to the F-15's design, it was also expected to out perform the expected performance of the Mig-25 which was actually ill-informed at that point.

The problems I have with PCA is that its not being designed to counter anything at this point.
1. Its not addressing the combat lessons learned from the F-22 and F-35.
2. It is not being designed to counter Russian or Chinese super planes which will challenge the F-22/35's superiority.

It is actually just trying to address the Range problems with current 5th gens. The B-21 needs an escort to reach China and back.

Until the F-22 faces real combat,
We have yet to fully acknowledge if that decision was right all along.
The F-15 and F-117 were also expected to perform spectacularly, but only got their validation once they finally saw combat. The same applies to the F-22 and F-35.

The F-22 and F-35 were designed based upon the combat experiences of the F-15/16/18 and F-117. Both have succesfully flown in highly dense electronic environments (Russian, Chinese, Iranian radar/ESM/EW). Russian/Chinese jets have far less combat experience, as their basis (much less in pilot training.) Our pilots have the advantage of not only significantly more flight hours, but regular cross training with allies. The Russians/Chinese have no training analogue.

I know a lot of people won't agree with my unpopular opinion. My only point is this. Aircraft designed from combat experience are always spectacular all the time. Aircraft designed from simulations/expectations are hit and miss.
PCA is included in the latter group. Who knows it might be awesome, but it could also be the next F-111

See my post above. There aren't any new designs, that aren't based upon 60+ years of combat experience/training lessons. Every new design takes lessons learned, from previous generations of aircraft. The F-111 was an outstanding aircraft, by the way.

We don't know what PCA will be yet, just because its newer doen't make it better. The F-111 was to replace the F-4, based on simulations and expectations of what air combat was supposed to be. but give me an upgraded F-4 instead of an F-111 to perform CAP any day.

The only correct statement you made, is that we don't know what the PCA will be. What we do know, is that it will have more range, be stealthier against a broader array of sensors, and have even greater sensor fusion than either the F-22 or F-35. Based upon the Block upgrade roadmap for both the F-22 and F-35, we can expect similar capabilities to be included (greater use of AI, directed energy weapons, DIRCM/MSDM, EW/EA, etc...). It's also likely to have greater speed and agility, to overmatch threats. You seem to be under the impression that LM/Boeing/etc..... are just going to design aircraft in a vacuum, and show them to the USAF, rather than the USAF using lessons learned/Intel on threats, to come up with the specifications. The issue with the F-111B, was that it wasn't suited for carrier operations. The F-14 greatly benefited from the lessons learned, though.

Not only was combat studies from Vietnam the primary contributing factor to the F-15's design, it was also expected to out perform the expected performance of the Mig-25 which was actually ill-informed at that point.

The problems I have with PCA is that its not being designed to counter anything at this point.
1. Its not addressing the combat lessons learned from the F-22 and F-35.
2. It is not being designed to counter Russian or Chinese super planes which will challenge the F-22/35's superiority.

It is actually just trying to address the Range problems with current 5th gens. The B-21 needs an escort to reach China and back.

The F-15 air superiority project started in 1965 whereas the Vietnam air war only started in 1964 so its lessons did not initiate the project. If anything it was Boyd's E-M theories that influenced the design rather than the small light Migs and a lot of fast century aircraft needed replacing too so a fast high energy fighter was created. If combat experience was the only driver then a Mig-21 clone would have been built.

If you wait to counter you will always be behind on innovation. What exactly is there to counter on J-20 and Su-57 ? Are you worried about super-maneuverability ? How difficult do you think it will be to retrofit a 3D nozzle to F-35 if the need arose ? Worried about ROFAR ? Plenty of time to find a RAM that works at 100 GHz. If we all waited for counters we would still be flying modernized bi/tri-planes because they still corner the best ! Also what combat experience has the F-22 had to base a requirement from ?

Stealth works and grants the owner surprise and survivability. However with current engine technology approaching double the thrust of the original F-15 there is a chance to now build a big stealth fighter with much greater range and extend the reach of stealth without sacrificing combat thrust/weight ratios or wing loading. F-35 cannot stealthily range all over Iran from UAE/Qatar and certainly not from Israel and Israel won't be buying any B-21 so there is already a pressing requirement for much greater stealth range not even considering the larger SCS/N Korea environment. European theatre is no longer the driver for fighter aircraft where air superiority was crucial irrespective of range.

"In April 1965, the Director of DDR&E called for studies on an air superiority fighter (FX configuration). An official requirements document was finalized in October 1965 and an RFP was sent out to 13 companies in Dec. 1965. Eight companies responded with proposals and following a downselect, four companies were asked to provide refined designs; in total, some 500 design concepts were developed. When the proposals were studied in July 1966, the resulting designs were roughly the size and weight of the TFX (F-111) and, like that configuration, they could not be considered an air superiority fighter.

In September 1968, a RFP for an "Air Superiority Fighter" was released to major aerospace companies. The RFP had requirements for a single-seat fighter having maximum take-off weight of 40,000 lbs for the air-to-air role with a maximum speed of M=2.5 and a thrust to weight ratio of nearly 1.0 at mission weight. It also called for a twin-engine design. Four companies submitted proposals, with the USAF eliminating General Dynamics, and awarding contracts to Fairchild Republic, North American Rockwell, and McDonnell Douglas for the definition phase in Dec. 1968. The companies submitted F-15 development proposals in June 1969. The Air Force announced the selection of McDonnell Douglas on Dec 23, 1969. The winning design resembled the twin-tailed F-14, but with fixed wings; the F-14 and F-15 were both based on configurations studied in wind tunnel testing by Langley. The F-15 first flew in July 1972 and entered service in 1976."

The air superiority fighter program was rolling before the Vietnam air war heated up. This quote is about as close to anything official I can find. I believe the basic configuration of what we think of as the F-15 was wind tunnel tested in 67 or 68 but wasn't the winning selection from MDD. The winning configuration as most of us know was like a single seat F-14. The as we know it F-15 design was selected later.

But back to point, the USAF had an air superiority fighter program underway before "learning it's lessons" from Vietnam. We don't wait for a war before advancing our air forces fleets.

The problems I have with PCA is that its not being designed to counter anything at this point.
1. Its not addressing the combat lessons learned from the F-22 and F-35.
2. It is not being designed to counter Russian or Chinese super planes which will challenge the F-22/35's superiority.

That is patently false. While no kinematic specifications have been determined yet, there's no evidence whatsoever that agility/speed/acceleration aren't factors in the PCA design. That being said, the biggest threat to aircraft, are enemy sensors and SAMs, which the PCA is clearly being designed to excel against.
Enemy aircraft are far less of a threat, which gives the PCAs systems an even bigger advantage against aircraft.

It is actually just trying to address the Range problems with current 5th gens. The B-21 needs an escort to reach China and back.

That is false. There's a lot more involved than just increasing range. I recommend taking a vacation from Wikipedia, for a while.

This is what you want, The F-15 Eagle: Origins and Development 1964-1972:

https://media.defense.gov/2012/May/16/2 ... 16-036.pdf

AFD-120516-036.pdf

(6.7 MiB) Downloaded 517 times

This is what you want, The F-15 Eagle: Origins and Development 1964-1972:

Great post thanks.

Not only was combat studies from Vietnam the primary contributing factor to the F-15's design..

Not far off really then - not only does it appear the project got actual backing after 1964 A-A combat results in Nam but was a big influence during the design period - how could it not be. The results in the late 60s gave a lot of fuel to the advocates of manoeuvrability (Agen & Boyd et al) over bigger higher faster concepts like the F-111.

Not only was combat studies from Vietnam the primary contributing factor to the F-15's design..

Not far off really then - not only does it appear the project got actual backing after 1964 A-A combat results in Nam but was a big influence during the design period - how could it not be.

Because there were no Su-15s or MiG-25s encountered over Vietnam. Nor any SA-3s or SA-4s.
But they had all flown by 1964.

Look-down/shoot-down was definitely a requirement driven by Vietnam A-A combat experience though.

The results in the late 60s gave a lot of fuel to the advocates of manoeuvrability (Agen & Boyd et al) over bigger higher faster concepts like the F-111.

Even the mid-60's indicated that air superiority was going to mean prevailing against a SAM + fighter threat.
Particularly given improved Soviet SAM mobility implied by the SA-4 which would make it resistant
to mid-60's SEAD tactics.

Now in an alternate future where TFX had met its supersonic maneuverability requirements....

1. F-15 was designed in the late 60s and the basic platform was conceived in 66 or 67 - not sure about selection. How many Thuds and Phantoms had been lost to Migs by that time period? It was designed around lessons learned from F-111.

2. The mighty Tomcat was designed solely around lessons learned from the F-111.

1. The F-111 contributed approximately 0.00% to the development of the F-15.

2. The Tomcat was influenced by the need to deal with the Foxbat and bomber-launched antiship missiles as well as have better air combat performance. The only "lesson" from the F-111B was "don't be that fat".

I don't recall anything about the F-14 being designed to deal with the Foxbat. Threat to the fleet from Soviet bombers and cruise missiles? Sure, but nothing I can recall about the Mig-25.

Do you have a source?

I'm not being difficult, just want to know if that really was the case. Because if it was, they certainly succeeded...

1. F-15 was designed in the late 60s and the basic platform was conceived in 66 or 67 - not sure about selection. How many Thuds and Phantoms had been lost to Migs by that time period? It was designed around lessons learned from F-111.

2. The mighty Tomcat was designed solely around lessons learned from the F-111.

1. The F-111 contributed approximately 0.00% to the development of the F-15.

2. The Tomcat was influenced by the need to deal with the Foxbat and bomber-launched antiship missiles as well as have better air combat performance. The only "lesson" from the F-111B was "don't be that fat".

I don't recall anything about the F-14 being designed to deal with the Foxbat.

One of the final tests in the test program was to demonstrate it could deal with a high-flying MiG-25 by shooting down a BOMARC target.

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If you wait to counter you will always be behind on innovation. What exactly is there to counter on J-20 and Su-57 ?

So we can all agree that the Teen series was at the very least, influenced by the Vietnam war. Maybe not initiated because of it, but certainly Vietnam was an influence, maybe even a major influence.

IIRC The ATF program was initiated because of intelligence reports regarding the T-10 and Mig-29 prototypes that may reach parity levels with the Teen series.

So both the Teen and 5th gen programs were responsive reactions to what future threats are. What exactly is PCA and F/A-XX reacting to? Is the superiority of the F-22/35 compromised already by the J-20 and Su-57?

Furthermore we have this:
https://www.defensenews.com/digital-sho ... r-designs/

Officials involved in the effort have described Penetrating Counter Air as a survivable aircraft that may have design elements similar to a bomber in order to give it a longer range.

.

If it pushed through, PCA will forgo traditional fighter characteristics like Speed and Maneuverability and will rely only on Stealth, SA and DI or standoff weapons.

So both the Teen and 5th gen programs were responsive reactions to what future threats are. What exactly is PCA and F/A-XX reacting to? Is the superiority of the F-22/35 compromised already by the J-20 and Su-57?

1. Presumably you've heard it's better to be proactive rather than reactive?

2. The F-22 was designed with the European theater in mind. Distances are much larger in the Pacific. The F-22 doesn't have the necessary range to be effective there. (Not unless you plan on getting all your tankers shot down in the first few days anyway.)

3. There are fewer than 200 F-22s in existence. About half that that can actually fight at any given moment (training, maintenance, etc.) The F-22 production line is GONE.

As for the F/A-XX for the USN and the F-35C, the F-35 is the LOW-end of the high/low mix. The USAF got the F-22/F-35A. The USN cancelled their F-22 (the NATF).

[

If you wait to counter you will always be behind on innovation. What exactly is there to counter on J-20 and Su-57 ?

So we can all agree that the Teen series was at the very least, influenced by the Vietnam war. Maybe not initiated because of it, but certainly Vietnam was an influence, maybe even a major influence.

IIRC The ATF program was initiated because of intelligence reports regarding the T-10 and Mig-29 prototypes that may reach parity levels with the Teen series.

So both the Teen and 5th gen programs were responsive reactions to what future threats are. What exactly is PCA and F/A-XX reacting to? Is the superiority of the F-22/35 compromised already by the J-20 and Su-57?

Furthermore we have this:
https://www.defensenews.com/digital-sho ... r-designs/

Officials involved in the effort have described Penetrating Counter Air as a survivable aircraft that may have design elements similar to a bomber in order to give it a longer range.

.

If it pushed through, PCA will forgo traditional fighter characteristics like Speed and Maneuverability and will rely only on Stealth, SA and DI or standoff weapons.

PCA is not reacting to anything, it is pressing an advantage and increasing the range of western fighter stealth. In WWII when the Germans had the potent Panther tank they still developed the even more potent Tiger tank with its big 88mm gun. You are also reading too much into that link, yes it will be big like a bomber and probably tail-less too but that does not mean it will definitely have the speed and maneuverability of a bomber, that's what design innovation will determine and anyway so what if it did if it's the only aircraft capable of being at that extreme range ? I am seeing a very big glass that is half full here not half empty.