Northrop F-18L History - you can design a better mouse trap but...

[BillRo]

F-18L internal fuel was 10,380 lbs and included wing fuel.

 

[Pioneer]

Thank's for your reply r16!

no aggression of any sorts is intented as well

All good mate, none taken

It's just that I was very curious as to the potential of a Turkish purchase, that I wasn't aware of.

Thank's again

Regards
Pioneer

 

[Archibald]

At the end of the day Northrop was really the most unhappy aircraft manufacturer between 1970 and 1990.

Just think about it

They had the P.530 Cobra mockup right from 1971 which morphed into the YF-17. Fine.
- YF-17: screwed by GD F-16
- YF-17 transformed into F-18 but Northrop had to enlist MDD per lack of Navy experience
- MDD promised Northrop the F-18L
- Northrop was screwed by MDD over the F-18L and everybody (from Switzerland to Australia) bought the 2000 pounds heavier F/A-18.

And it was only a beginning. The F-5G / F-20 fiasco was coming.

- Northrop was screwed a first time in the case of the F-5G to Taiwan (no Sparrow for them, it makes the PRC nervous), Carter FX, and GD F-16/79
- Northrop was screwed another time when Reagan brought back the F-20, did nothing about it (1982 declaration with the PRC only weeks before the first F-20 prototype flew, in summer 1982)
- and Northrop was screwed one last time in 1986 when the ANG, who liked their aircraft, was forced to pick the F-16 ADF

Seriously, if I had been the boss of Northrop (Jones) I would have grown ulcers or aneuryms or coronaries about the entire thing.
Just imagine: they had three perfectly good aircrafts
- YF-17
- F-18L
- F-20
None of them ever entered service.

The story of Northrop post F-5E fighters is really bizarre, and a total waste of excellent designs. Plus the pair of F-20 that crashed with a pilot dead.

 

[sferrin]

And let's not forget the YF-23.

 

[Archibald]

At least they got the B-2 contract ! ;D Must have brought them a boatload of money.

 

[TomcatViP]

Things turned not that bad that they had to make more than a single bite out of Grumman

Wiki:

In 1994, Northrop Aircraft bought Grumman Aerospace, which built the Apollo Lunar Module to create Northrop Grumman (NG).[citation needed] In 1996, the new company acquired Westinghouse Electronic Systems, a major manufacturer of radar systems,[citation needed] and Xetron Corporation. In 1997, the defense computer contractor Logicon was added, which had acquired Geodynamics Corporation in March 1996 and Syscon Corporation in February 1995.[citation needed]

In 1998, a merger between Northrop Grumman and competitor Lockheed Martin was considered but abandoned after resistance from the Department of Defense and Department of Justice.[24] That same year, it acquired Inter-National Research Institute Inc. In 1999, the company acquired Teledyne Ryan, developer of surveillance systems and unmanned aircraft, California Microwave, Inc., and the Data Procurement Corporation.

Some starving have been more severe

 

[sferrin]

At least they got the B-2 contract ! ;D Must have brought them a boatload of money.

It might have if they'd made more than 20.

 

[Sundog]

What I found most interesting is that the Cobra was being developed for Australia, or they at least were one of the primary drivers of the mission profile. IIRC West Germany was really interested in it as well. Then it morphed into the YF-17 for the LWF demonstration, which then became the NATO F-104 replacement program and the rest is history.

With regard to how often Northrop was screwed over during this period, I keep thinking any year now we will find out about some secret aircraft program they won in the 90s to make up for it. I still remember when the down select was made for the ATF and it was the YF-22 and everyone I knew thought, "really?" I definitely knew it was a political decision when the response at Aviation Week was basically, "O.K., everyone shut up about it and fall in line behind the F-22 program." Which, don't get me wrong, the F-22 is the second best fighter this country ever designed, but....

 

[marauder2048]

Northrop was never able to shake its reputation in certain Air Force circles
for a being a glorified hobby shop.

That Northrop's final EMD proposal for ATF constituted an almost complete redesign over the YF-23
Dem/Val aircraft didn't help alter this perception.

 

[Archibald]

What I found most interesting is that the Cobra was being developed for Australia, or they at least were one of the primary drivers of the mission profile. IIRC West Germany was really interested in it as well.

I always assumed the Netherlands as the driver behind the P.530, as the next logical step after their NF-5s ?

 

[Sundog]

Northrop was never able to shake its reputation in certain Air Force circles
for a being a glorified hobby shop.

That Northrop's final EMD proposal for ATF constituted an almost complete redesign over the YF-23
Dem/Val aircraft didn't help alter this perception.

Northrops design wasn't a complete redesign. In fact, it was Lockheed who had to completely redesign their prototype and the competition was even put on hold for them to do it.

There are always redesigns going from Prototype to EMD. The entire front of the Raptor from just in front of the weapons bay forward was completely redesigned, as were the wing and tail and all of the edges had to be redesigned to maintain edge alignment as a result. The main landing gear was also completely redesigned. In fact, considering the only things that didn't change in going from the YF-22 to the F-22 were the location of the weapons bays and engines, one could argue that there were greater changes to the Lockheed Martin proposal than the Northrop-McDonnell Douglas proposal. So your argument is largely specious.

 

[LowObservable]

A common factor in the F/A-18L and F-20 stories was the reluctance of export customers to buy anything except what the US services had bought. That said, I wonder whether the 18L would have had the same problems (drag, handling, structures) as the P-530's other descendants, and while the F-20 could have been a fascinating niche player I doubt that it would have enjoyed the F-16's development and upgrade potential.

And as cool as the YF-23 was... would it have had the same kind of issues as the F-22? The real what-if in that story is the USAF's snap decision (1985-86) to accept the promise of all-aspect stealth for ATF.

 

[Sundog]

A common factor in the F/A-18L and F-20 stories was the reluctance of export customers to buy anything except what the US services had bought. That said, I wonder whether the 18L would have had the same problems (drag, handling, structures) as the P-530's other descendants, and while the F-20 could have been a fascinating niche player I doubt that it would have enjoyed the F-16's development and upgrade potential.

And as cool as the YF-23 was... would it have had the same kind of issues as the F-22? The real what-if in that story is the USAF's snap decision (1985-86) to accept the promise of all-aspect stealth for ATF.

Have you ever seen anything definitive regarding the primary causes of the F/A-18's drag issues? Large wetted area to internal volume ratio? I know the YF-17 was designed using differential area ruling (the area ruling over the top was different from the underside as it was optimized to minimize drag at a it's maximum turn rate at M=1.2) and IIRC Mac did away with this to make the spine larger to increase internal volume. I was wondering if that contributed to the drag problems? I've tended to lean towards, as noted first, a lot of wetted area for the given volume and a lot of interference drag contributions due to the strake to body configuration.

 

[LowObservable]

I asked the designer of a competing fighter that question, back when the Super Hornet was failing to live up to promises of greatly improved range.

His view was that the shape was so complex (two inlets, two tails, big Lerxes with slots and other devices, weapons and sensor pods close to the body) that the airflow became increasingly hard to predict or model the further aft you got.

 

[Ogami musashi]

Northrop was never able to shake its reputation in certain Air Force circles
for a being a glorified hobby shop.

That Northrop's final EMD proposal for ATF constituted an almost complete redesign over the YF-23
Dem/Val aircraft didn't help alter this perception.

Northrops design wasn't a complete redesign. In fact, it was Lockheed who had to completely redesign their prototype and the competition was even put on hold for them to do it.

There are always redesigns going from Prototype to EMD. The entire front of the Raptor from just in front of the weapons bay forward was completely redesigned, as were the wing and tail and all of the edges had to be redesigned to maintain edge alignment as a result. The main landing gear was also completely redesigned. In fact, considering the only things that didn't change in going from the YF-22 to the F-22 were the location of the weapons bays and engines, one could argue that there were greater changes to the Lockheed Martin proposal than the Northrop-McDonnell Douglas proposal. So your argument is largely specious.

I think you confuse the EMD and Final production versions. The F-23EMD wasn't the final production version. Had northrop won the contract, there would have been a critical design review with a frozen design chosen around 1992. The same went with lockheed. Their EMD version wasn't the final production design since they did the critical design review in 92, one year after being awarded the contract. There were several different versions of F-23 being studied for after the EMD phase, but since northrop lost the ATF, the studies stopped (at least in the white world).

As for the F-23 being all aspect and the F-22 not, i don't think this is true. Secretary cheney made it clear during the award conference that both planes were very similar including stealth and that there were only nuances. He however made it pretty clear that the LM was the low bider and that they had better confidence in LM than Northrop.

 

[LowObservable]

The point I was making was that both the ATF designs were all-aspect LO. That wasn't a requirement until Lockheed and Northrop assured the AF that it could be done, and done affordably.

 

[Ogami musashi]

The point I was making was that both the ATF designs were all-aspect LO. That wasn't a requirement until Lockheed and Northrop assured the AF that it could be done, and done affordably.

ah ok

 

[Sundog]

Northrop was never able to shake its reputation in certain Air Force circles
for a being a glorified hobby shop.

That Northrop's final EMD proposal for ATF constituted an almost complete redesign over the YF-23
Dem/Val aircraft didn't help alter this perception.

Northrops design wasn't a complete redesign. In fact, it was Lockheed who had to completely redesign their prototype and the competition was even put on hold for them to do it.

There are always redesigns going from Prototype to EMD. The entire front of the Raptor from just in front of the weapons bay forward was completely redesigned, as were the wing and tail and all of the edges had to be redesigned to maintain edge alignment as a result. The main landing gear was also completely redesigned. In fact, considering the only things that didn't change in going from the YF-22 to the F-22 were the location of the weapons bays and engines, one could argue that there were greater changes to the Lockheed Martin proposal than the Northrop-McDonnell Douglas proposal. So your argument is largely specious.

I think you confuse the EMD and Final production versions. The F-23EMD wasn't the final production version. Had northrop won the contract, there would have been a critical design review with a frozen design chosen around 1992. The same went with lockheed. Their EMD version wasn't the final production design since they did the critical design review in 92, one year after being awarded the contract. There were several different versions of F-23 being studied for after the EMD phase, but since northrop lost the ATF, the studies stopped (at least in the white world).

As for the F-23 being all aspect and the F-22 not, i don't think this is true. Secretary cheney made it clear during the award conference that both planes were very similar including stealth and that there were only nuances. He however made it pretty clear that the LM was the low bider and that they had better confidence in LM than Northrop.

I understand that EMD isn't the same as the production design, but the fact remains that what Northrop was looking at didn't have as big of a configuration change as the production F-22 did when compared to the YF-22, which is something they, Lockheed Martin, knew would be required for their submission based on some of the feedback from the pilots flying the YF-22. For instance, it was known before their final submission that the inlets would have to be moved back and the cockpit forward for better visibility down to the side from the cockpit.

 

[marauder2048]

That wasn't a requirement until Lockheed and Northrop assured the AF that it could be done, and done affordably.

Didn't that requirements change happen during the Dem/Val proposal phase when you still had
Boeing, GD, MacAir, Rockwell and Grumman?

In fact, considering the only things that didn't change in going from the YF-22 to the F-22 were the location of the weapons bays and engines,

IOW, the very high-risk areas the AF had identified and that Lockheed specifically set out to address in Dem/Val.
More importantly, Lockheed was not compelled to redesign because their flight and other measured performance
failed to substantially match their "sealed envelope" predictions unlike say the acoustics in Northrop's weapons bay.

My own takeaway is that CFD was not sufficiently mature nor as widely used by the Northrop-McAir team which
would come back to haunt that same team with the AWS on the Super Hornet.

 

[overscan (PaulMM)]

We are fairly far off topic but...

Northrop and McDonnell took Northrop's existing design, refined starting 1983 and pretty recognizably the YF-23 by 1986, as their ATF design.

Lockheed, General Dynamics and Boeing threw their existing configurations away in 1986 and effectively started from scratch.

In both cases the prototype configuration was frozen months (years?) before the submission in order to be built. It wouldn't be surprising if YF-22 was less representative of planned production configuration due to the shorter time of development.

In the LWF competition, Northrop continuously evolved their LWF design from 1966 onwards, but major design features were fixed by 1968 or so and the shape refined in minor ways. General Dynamics seem to have tested a lot more options of tail, wing configuration, inlet, etc, and the final design emerged much later in time, yet Northrop hit more aerodynamic snags by far with their design, despite its 'maturity'.

 

[overscan (PaulMM)]

That wasn't a requirement until Lockheed and Northrop assured the AF that it could be done, and done affordably.

Didn't that requirements change happen during the Dem/Val proposal phase when you still had
Boeing, GD, MacAir, Rockwell and Grumman?

Yes, but it was Lockheed and Northrop (as stealth experts with real hardware on their resume) who convinced the USAF it was doable, which is why the RCS requirement changed from ""pretty low, especially from the front" to "freaking unbelievable in every direction".

 

[icyplanetnhc (Steve)]

IIRC, Mr. Dan Raymer’s aircraft design book briefly discussed the Rockwell ATF proposal during its discussion of supersonic drag; Rockwell’s proposal (along with proposals from several other contractors) would have been much more focused on supercruise before the VLO requirements were significantly higher, as evidenced by a plot comparing its drag coefficient with Mach number against other aircraft. During a guest event at UCLA a few years ago he verbally said something similar. In fact, during the ATF RFI, Lockheed's initial proposal resembled a downsized A-12/SR-71.

The Northrop/McDonnell Douglas YF-23 (DP-117K) was extremely similar to Northrop’s submission for the ATF RFP (DP-110). On the other hand, the Lockheed/Boeing/General Dynamics team initially tried to refine Lockheed’s configuration 090P, but abandoned it when weight became a serious issue, and conducted a complete redesign into the F-22 shape we see now. Interestingly, the F-22’s current design looks quite like a tailed version of GD’s ATF submission, which was designed for supercruise and maneuver, but sacrificed all-aspect stealth with the single vertical tail as they weren’t able to work out another empennage configuration successfully. Evidently the stabilitors and canted vertical tails were able to overcome this problem, although I’m not sure why GD didn’t try to add stabilators when they tried split verticals mounted on booms.

 

[Mike Pryce]

My own takeaway is that CFD was not sufficiently mature nor as widely used by the Northrop-McAir team which
would come back to haunt that same team with the AWS on the Super Hornet.

McAir did a pretty bad job on the AV-8B with drag too. It may have been too much faith in calculating drag - put a fighter in a turn and modern CFD still can't work it out. Need proper tunnel tests and attention to detail design to this day. Reading across from the A or Y model may have been the problem.

 

[LowObservable]

In the ATF story, three related things happened between the initial RFP in Sept 1985 and source selection in Oct 1986:

- Northrop and Lockheed responded with all-aspect stealth designs, and the AF extended the deadline to late Apr 86.

- In May 86, the AF announced that it would add flying prototypes to the two Dem-Val contracts.

- Weeks after that, the three mid-pack competitors (Boeing, Macs and GD) teamed around Lockheed and Northrop.

 

[Sundog]

Regarding the YF-17, one of the other problems the prototypes had was horizontal tail stiffness. They were getting too much bending/aero-elastic effects in their tails, which had an adverse affect on performance as well.

 

[Pioneer]

Gents, if the Northrop F-18L had of been selected by a foreign air force, what would the forum's guess as to when it could have been manufactured?

Did Northrop give any such timeline once a substantial order was taken?

Regards
Pioneer

 

[Ogami musashi]

I understand that EMD isn't the same as the production design, but the fact remains that what Northrop was looking at didn't have as big of a configuration change as the production F-22 did when compared to the YF-22, which is something they, Lockheed Martin, knew would be required for their submission based on some of the feedback from the pilots flying the YF-22. For instance, it was known before their final submission that the inlets would have to be moved back and the cockpit forward for better visibility down to the side from the cockpit.

My point is not that YF-23 to F-23 was more radical; My argument is that we don't know because:
1/ The F-23 was never selected so the critical design review never happened.
2/ During the dem/val efforts, configurations would change on a daily basis, thus the moment that radical configurations changes occurred may not have been the same for NG and LM. Yet, we don't know what was the EMD F-22 configuration.

What you quote about the flight testing affecting the design is equally true for the F-23, and based on that, the amount of changes was tremendous. The inlets were redesigned after flow distortion was discovered, similarly the weapon bay configuration was changed following concerns about structural integrity of the YF-23 like configuration. The length of the fuselage was changed too (DP 232 was just an interim iteration, even if GE was selected the design would have converged towards the DP 231 with shorter fuselage and three spike aft deck).

So, if we can't compare neither full scale production (because one never existed) or even EMD (because one is unknown), how can be say that F-22 was a more radical redesign than the F-23?

 

[Sundog]

My point is not that YF-23 to F-23 was more radical; My argument is that we don't know because:
1/ The F-23 was never selected so the critical design review never happened.
2/ During the dem/val efforts, configurations would change on a daily basis, thus the moment that radical configurations changes occurred may not have been the same for NG and LM. Yet, we don't know what was the EMD F-22 configuration.

What you quote about the flight testing affecting the design is equally true for the F-23, and based on that, the amount of changes was tremendous. The inlets were redesigned after flow distortion was discovered, similarly the weapon bay configuration was changed following concerns about structural integrity of the YF-23 like configuration. The length of the fuselage was changed too (DP 232 was just an interim iteration, even if GE was selected the design would have converged towards the DP 231 with shorter fuselage and three spike aft deck).

So, if we can't compare neither full scale production (because one never existed) or even EMD (because one is unknown), how can be say that F-22 was a more radical redesign than the F-23?

Because the F-23 didn't have a redesigned wing and tail, other than modifications with the boat tail of the aircraft, since the YF-23 was designed to have thrust reversers, which the production version didn't have to accommodate. The wings and tail on the F-22 were completely redesigned from the prototype to the production version.

 

[icyplanetnhc (Steve)]

Sundog, did something swallow up your response?

 

[LowObservable]

At one point just before source selection, one of the Northrop senior engineers gave a presentation that included an artist's concept that he said had accompanied the Dem-Val proposal. It was identical to the YF-23.

 

[Ogami musashi]

My point is not that YF-23 to F-23 was more radical; My argument is that we don't know because:
1/ The F-23 was never selected so the critical design review never happened.
2/ During the dem/val efforts, configurations would change on a daily basis, thus the moment that radical configurations changes occurred may not have been the same for NG and LM. Yet, we don't know what was the EMD F-22 configuration.

What you quote about the flight testing affecting the design is equally true for the F-23, and based on that, the amount of changes was tremendous. The inlets were redesigned after flow distortion was discovered, similarly the weapon bay configuration was changed following concerns about structural integrity of the YF-23 like configuration. The length of the fuselage was changed too (DP 232 was just an interim iteration, even if GE was selected the design would have converged towards the DP 231 with shorter fuselage and three spike aft deck).

So, if we can't compare neither full scale production (because one never existed) or even EMD (because one is unknown), how can be say that F-22 was a more radical redesign than the F-23?

Because the F-23 didn't have a redesigned wing and tail, other than modifications with the boat tail of the aircraft, since the YF-23 was designed to have thrust reversers, which the production version didn't have to accommodate. The wings and tail on the F-22 were completely redesigned from the prototype to the production version.

Again, my point is that you can't compare an EMD and a full production version. Read my previous post's points onto why i think this is of prime importance regarding your argument.

 

[Pioneer]

Just stumbled cross this interesting snippet of information re the F-18L (which if it's been posted elsewhere, I apologise!)

Tehran also wanted a whopping 250 F-18s. The U.S. Navy at the time wanted 800 F-18s for its aircraft carriers. Iran proposed providing the Northrop Corporation $8 million to develop the land-based variant, referred to in the press at the time as the F-18L, which would have been lighter than the naval version (“Iran Offers F18 Aid”, UPI, October 28, 1976). This was quite unusual, since the Pentagon never permitted a foreign government to finance the creation of a warplane. The Shah ultimately proved no exception to this rule. While the U.S. Navy supported the development of the F-18L for Iran, believing that it would reduce the cost of production for its own F-18As, the Carter administration ruled out the sale. Carter did not want to promote foreign sales to lower the cost of equipment for the U.S. military, sought to prevent arms sales that did not contribute to U.S. security and outright forbid the “development or significant modification of advanced weapon systems solely for export.” (Charles W. Corddry, “US denies Iran’s bid for 250 jets”, Washington Bureau of The Sun, June 18, 1977). Furthermore, the Pentagon clearly never took the idea very seriously. “The Pentagon’s relaxed treatment of the matter is evident in its failure even to estimate the total price of 250 Northrop F-18Ls, including spare parts, ground-support equipment and crew training,” noted one news report. “Mr. Carter nevertheless stands to gain from this seeming early test of his new policy on foreign arms sales. And by informed accounts, the Shah of Iran probably is not miffed.” (Corddry, 1977).

(Source: Paul Iddon, 2018.In the 1970s the Shah sought to make Iran a military superpower)


Regards
Pioneer

 

[hesham]

Very nice my dear Poineer,

and Shah of Iran actually asked for 300 units,reduce into 250,and he also asked for 100 F-15 and 150 F-16,as in his Diary when he lived in Egypt.

 

[red_october]

Gents, if the Northrop F-18L had of been selected by a foreign air force, what would the forum's guess as to when it could have been manufactured?

Did Northrop give any such timeline once a substantial order was taken?

Regards
Pioneer

I happen to come to this thread and thought to ask the very same question lol

Just stumbled cross this interesting snippet of information re the F-18L (which if it's been posted elsewhere, I apologise!)

Tehran also wanted a whopping 250 F-18s. The U.S. Navy at the time wanted 800 F-18s for its aircraft carriers. Iran proposed providing the Northrop Corporation $8 million to develop the land-based variant, referred to in the press at the time as the F-18L, which would have been lighter than the naval version (“Iran Offers F18 Aid”, UPI, October 28, 1976). This was quite unusual, since the Pentagon never permitted a foreign government to finance the creation of a warplane. The Shah ultimately proved no exception to this rule. While the U.S. Navy supported the development of the F-18L for Iran, believing that it would reduce the cost of production for its own F-18As, the Carter administration ruled out the sale. Carter did not want to promote foreign sales to lower the cost of equipment for the U.S. military, sought to prevent arms sales that did not contribute to U.S. security and outright forbid the “development or significant modification of advanced weapon systems solely for export.” (Charles W. Corddry, “US denies Iran’s bid for 250 jets”, Washington Bureau of The Sun, June 18, 1977). Furthermore, the Pentagon clearly never took the idea very seriously. “The Pentagon’s relaxed treatment of the matter is evident in its failure even to estimate the total price of 250 Northrop F-18Ls, including spare parts, ground-support equipment and crew training,” noted one news report. “Mr. Carter nevertheless stands to gain from this seeming early test of his new policy on foreign arms sales. And by informed accounts, the Shah of Iran probably is not miffed.” (Corddry, 1977).

(Source: Paul Iddon, 2018.In the 1970s the Shah sought to make Iran a military superpower)


Regards
Pioneer

Oh, this actually happen before the revolution due to Carter?

Darn, so the US Gov might have effectively (although indirectly) killed two Northrop birds with one policy? With the implementation of it (F-18L) and the end of it (F-20).

If this deal actually continue it could be crucial, paving the way for more orders (with the customers seeing that the US actually support the F-18L's infrastructure, without needing to buy exactly the same one as USN, like Canada)

 

[kaiserd]

Well considering how it worked out probably just as well Iran didn’t have F-18Ls post-revolution.
And to be fair the Carter Administrations policies helped create the F-20; it was policy decisions by the following Regan administration that killed it.

 

[Fluff]

Yes, good job all round, trapping them into those useless F14's, which wouldn't stay serviceable for 3 months, once we cut off the spare parts supply.........

 

[JFC Fuller]

Well considering how it worked out probably just as well Iran didn’t have F-18Ls post-revolution.
And to be fair the Carter Administrations policies helped create the F-20; it was policy decisions by the following Regan administration that killed it.

Given that the Shah simply signed a Letter of Intent for F-16s (October 1976) instead it is safe to assume that it would have made no difference to post revolution Iran whatsoever, other than it being 300 F-18Ls that the Iranian Air Force ended up not getting rather than the 300 F-16s that history otherwise records as casualties of said revolution.

 

[Archibald]

israel got these F-16s instead...

 

[kaiserd]

Well considering how it worked out probably just as well Iran didn’t have F-18Ls post-revolution.
And to be fair the Carter Administrations policies helped create the F-20; it was policy decisions by the following Regan administration that killed it.

Given that the Shah simply signed a Letter of Intent for F-16s (October 1976) instead it is safe to assume that it would have made no difference to post revolution Iran whatsoever, other than it being 300 F-18Ls that the Iranian Air Force ended up not getting rather than the 300 F-16s that history otherwise records as casualties of said revolution.

Yes that was always most likely given the likely delivery dates and the date of said revolution.

 

[F-2]

Tony Chongs book Flying Wings & Radical things page 191 gives a weight savings of 1650 lbs. this seems to be at odds with marketing material posted earlier (2500 lbs give or take) it does cite Northrop documents though. He also talks about updated F404 engines in the 18000lbf range. Their seems to be a lot of talk about options that a buy can add to the jet or omit. Perhaps that’s the source of the discrepancy?