Northrop / McDonnell Douglas ATF - YF-23 and EMD F-23

[kagemusha]

1) What was the top speed in supercruise of the YF-23?

2) How was the main weapons bay configuration (type of launchers and number of missiles) of the F-23?

Thank you!

 

[Ogami musashi]

Here are the questions sent, If you have questions that are not on the mail i sent then i suggest asking Billro if he can forward them.



Main questions:


YF-23:


1/What is your opinion on the YF-23 maneuverability. It has been said that thanks to TVC, the YF-22 was more maneuverable, but was it the case across the tested envelope or just low speed?


2/There's some confusion about supercruise speed achieved by the YF120-GE-100 powered YF-23. The legend is that it is still classified. Is it the case? According to available data the maximum mach tested for YF-23 PAV-2 was mach 1.72 so it suggests the supercruise speed was not greater. How can you confirm this data?






F-23:


1/Recently declassified blueprints of an F-23 EMD version dated December 1990 were released. Those drawings show a much altered design. Was it supposed to be the almost definitive version of the F-23? The mid fuselage section seems to be much larger than on the YF-23. How this version differed in estimated performance over the YF-23 in term of supercruise speed, weight,speed, range, maneuverability and weapons load out?


2/The weapons bays on the F-23 EMD seem to be much shallower than the one on the YF-23. This has prompted some questions:
Would the F-23 EMD be able to carry 8 AMRAAMS + 2 SRAAMS? Recently Barry Watts said that the F-23 would have been able to carry 2000lbs weapons and that the plane would have been able to supercruise at mach 1.4 for the all mission as opposed to the supercruise radius of F-22 of 100nm. Was it something planned back in 1990 with this version?





Additional questions:


YF-23:


1/Did either PAV-1 or -2 go supersonic with open weapons bays or was that done always subsonic? Either break the sound barrier with open bays or open them while being supersonic.


2/In your opinion, did the canceled NATF weigh in a lot on the decision to go with F-22 over F-23?




F-23


1/It has been suggested that USAF was worried about the single bay and the rack system on YF-23 (jamming), was that the reason why F-23 had two weapons bays? Or was that just a natural design progression not necessarily tied to USAF?


2/The two weapons bays seem to be connected (their doors are connected) on the F-23. Was there a separation between the two or loading a weapon across both would have been possible?


3/It has been suggested that USAF was worried about the single bay and the rack system on YF-23 (jamming), was that the reason why F-23 had two weapons bays? Or was that just a natural design progression not necessarily tied to USAF?


4/And finally a very broad question to both Jim and Paul and surely will be asked during the lecture but: "In retrospect what would you choose for ATF, F-23 or F-22?"

 

[bring_it_on]

I am planning on going - send me questions.

Hope you are planning to make a video (if its allowed)...I know it would be put up on there channel but something much quicker never hurts

 

[BillRo]

That is a lot of questions and I am not sure that they will let me monopolize the proceedings, but I will do my best. I am planning on making an audio recording but video may not be practical. I am sure that a video will become available in the future as they have for the other WMOF talks. I will ask and see if they will confirm that.

Bill

 

[overscan (PaulMM)]

Bill, use your best judgement. I guess most of them can be summarised as - did the USAF make a mistake not to order the F-23? I don't think you'll get an answer to that.

 

[sferrin]

Bill, use your best judgement. I guess most of them can be summarised as - did the USAF make a mistake not to order the F-23? I don't think you'll get an answer to that.

Hopefully someday he'll be able to tell all. He's one of the very few to have flown both the YF-23 and F-22A.

 

[bring_it_on]

That is a lot of questions and I am not sure that they will let me monopolize the proceedings, but I will do my best. I am planning on making an audio recording but video may not be practical. I am sure that a video will become available in the future as they have for the other WMOF talks. I will ask and see if they will confirm that.

Bill

Thanks Bill. Have fun!!

 

[Ogami musashi]

Actually there may be some misunderstanding.


The questions here have been sent. They will be printed and Paul and Jim will see them not on Saturday during the lecture but today hence why i was allowed to ask more than a couple of questions.


Thus if you have questions that were not on the mail, i suggest you may ask Billro if he can ask them during the lecture

 

[flanker]

I assume they will both stick around for a bit after the presentations, so it should be possible to ask some additional questions after presentations. And if we have atleast two mos eisley cantina representatives asking two questions each in plenum that is already 4 questions covered.

 

[BillRo]

OK Ogami I will ignore that big list since you have it covered; we hope that the presentation will include answers, in which case my recording can be a record until the video comes out. I have a couple of other question from a few including Grigory and will concentrate on those.

Bill

 

[Ogami musashi]

OK Ogami I will ignore that big list since you have it covered; we hope that the presentation will include answers, in which case my recording can be a record until the video comes out. I have a couple of other question from a few including Grigory and will concentrate on those.

Bill

great!

 

[BillRo]

I went to the WMOF event today in Torrance and saw a bunch of my "old" Northrop colleagues; some came from as far away as the US East Coast and some that I hired from college were retired. PAV-2 was parked outside and both Paul Metz and Jim Sandberg were there and shared the presentation. The whole thing was video taped by the Palos Verdes couple who have done the rest and it will be available in a month. I thanked them for their efforts and told them how much the historical aviation community enjoys their work.

Attached are a few pix. I will pick up the previous threads and answer as many questions there that I can plus some I received separately. You will be able to get more precise answers when the video is released. I made a recording but I have not checked as to its quality yet.

Bill

 

[Ogami musashi]

Thanks BillRo!

 

[bring_it_on]

Thanks BillRO..appreciate your effort. I just noticed that they had put pictures of the YF23 getting prepped for the event on their Facebook page. .




https://www.facebook.com/permalink.php?story_fbid=886984998057724&id=130363370386561

 

[quellish]

I heard there will be punch and pie, so...

No punch and pie, but even better - hot dogs!

 

[Sundog]

For reference, I asked Bill to ask if the EMD F-23 or the NATF were ever in the simulator. Bill said he spoke with Paul Metz afterward and Mr. Metz said neither of those aircraft were ever in the simulator, but the actual YF-23s matched what he flew in the simulator and that the YF-23 was the best handling aircraft he has ever flown.

 

[Stargazer]

That's awesome, BillRo!! Thanks for your efforts, and I can't wait to hear the answers to some of the questions...

 

[Steve Pace]

Way to go BillRo! -SP

 

[BillRo]

Paul Metz/Jim Sandberg talk
at the YF-23 25th Anniversary of First Flight, WMOF Torrance, CA 15 Aug 2015

Summary; These are my interpretations of what was said during a 90 minute talk, based on a tape recording of the event. Prior to commenting, I would suggest waiting until you have viewed the video, due in a month or so, in case I have misinterpreted the words and figures. Also some useful charts and familiar videos were shown.

The talk was divided into 3 parts:

Paul Metz, Chief Test Pilot: Introduction - How ATF and the Northrop submission came about.
Jim Sandberg, Test Pilot PAV-2: YF-23 Flight Test.
Paul Metz: Conclusions.

Paul Metz:

ATF started in 1971 in response to increased Soviet capability - IL-76-based Mainstay AWACS with look-down radar, MiG-29 Fulcrum and SU-27 Flanker with look-down, shoot-down capability and next-generation improved, higher performance SA-2-type missiles. USAF and many companies were involved; an interesting chart was presented here showing the various study configuration planforms. Seven companies responded in 1981 to a Request for proposal but no-one had thought about stealth.

Reduced signature was mentioned in terms of levels - Generation 0, Horton 229; Generation 1, SR-71; Generation 2, F-117; Generation 3, B-2 and Generation 4, ATF which had to have long range, large internal payload AND maneuverability. It also had to have the ability to find the enemy without giving away its position. Sandusky had a team embedded within B-2 at Pico Rivera to assimilate the technology.

When Northrop and Lockheed were selected there were no specs - the contractors determined them. Three months before the proposal was due the Air Force made a change and asked for a demonstrator - the requirement was for it to fly once. Northrop and its team contributed half the cost and invested $1.1B.

The competition was not a fly-off and you cannot make apples to apples comparisons since the NAD and Lockheed flight test programs were not the same.

Jim Sandberg: Flight Test

The YF-23 has very large canted tails which add to the lift, give an unmatched rearward view and with their powerful fast actuators provide agility equivalent to 2D thrust vectoring. Vectoring was considered by Northrop but discarded in favor of the cooled trough (which obviously offered significant signature advantages) and powerful controls.

The aircraft used parts and pieces from several different planes including wheels and brakes from the F-18 - a lighter aircraft, so care had to be taken after landing and while taxiing. Ground crews checked the temperatures after roll out.

Original test program called for 350 sorties, actually it was 3 months and 50 sorties. Five pilots flew the aircraft, as well as Paul and Jim, Joe Lowe? From McAir and two from the USAF.

The first flight was practiced for over a year (due to delays). The test program was designed to demonstrate supercruise, flying qualities throughout the envelope and aerial refueling, since that was employed to maximise flight test time. A chart shown with test results - number of flights, max speed (demonstrated) PAV-1 M=1.8 PAV-2 M=1.7, max angle of attack and max altitude about 50K feet.

PAV-1 flew perfectly with no problems until flight 6 but PAV-2 (Jims plane) was a different story; it flew 2 months later and he also had a team that practiced everything at the Air Forces insistence. Jim thought it would be easy - Paul had flown PAV-1 (with the PW engine) and Lockheed had flown the GE engine.

They used runway 8 at Edwards, opposite to the normal flow of traffic (so that in case of problems the aircraft would be heading away from populated areas). As soon as he released the brakes and was rolling he saw a white light at the end of the runway and thought it was a truck, it soon disappeared and he continued only to see a T-38 landing in the opposite direction in spite of all the practice. Then after retracting the gear, the mains failed to extend leaving just the nose gear. They discussed it for a while, cycled the gear again, and everything locked in position. The crew suggested Jim leave the gear down - Jim agreed!

On the second flight, approaching the tanker Jim found the difference between the two engines. He had flown PAV-1 (Pratt) and had no problems refueling, but the GE motor was difficult to modulate and in the end he set one engine idle and the other at power to achieve engagement. Then before any testing could be accomplished there was an engine malfunction and he had to RTB.

On the third flight climbing to 27K with Paul in chase, he heard “You are venting” and ground said “Descend, descend” A valve in the fuel tank pressurization equalization system had malfunctioned, over-pressurizing the tank to almost 150% of design load.

Interesting supercruise chart here showing the comparative speed (no scale) of the two Northrop and the two Lockheed aircraft. The GE powered aircraft were slower than the Pratt planes and the YF-23 PAV-1 was faster than the YF-22 aircraft. The Air Force chose the slowest plane with the slowest engine!

Paul: Conclusion

“In prototyping competitions there is a tangible and intangible impression you leave with your customers”. Northrop engineering skills are beyond compare and they successfully predicted the YF-23 performance and other aircraft with which he was associated. Northrop presents the aircraft in engineering terms - graphs charts etc. But not every one who is in a position to select your aircraft is an engineer, so there is another way to leave an impression. He then showed that classic picture of the contrails of an F-16 turning inside an F-4, a picture of the F-22 at a 60 deg angle of attack and another of it launching a missile. Northrop could have done the exact same thing but Lockheed understands how to leave those impressions.

Questions:
The YF-23 can stand beside anything out there and in many cases exceed them. The airplane is a Mach 2 class airplane but neither Northrop nor Lockheed took the aircraft to their absolute maximum. Both aircraft were judged to be technically acceptable, so the decision must have been made on non-technical issues. (The airplane only represents 1/3 of the solution - the other 1/3 is avionics and the final 1/3 is management, support manufacturing etc) Sec. Rice said both planes were qualified but he had greater confidence in Lockheed’s ability to manage the program!
Supercruise: Started at M=.85 at 42k and ran full Mil power till it conked out. Speed increased steadily and AB was not required to punch through the number. They felt that perhaps the engine decision was influenced by the need to preserve the capabilities of more than one fighter engine producer, but that was not the case for the airframe. The main benefits in technology carried forward was in the area of avionics. YF-23 would not have been carrier capable - NATF looked completely different.

How much fun was it? Pilots are really focused but when the test cards were made up for Paul, Jim put in between two points once everything had settled “Look out the window and enjoy”. When they were production test pilots delivering F-5s all over the world one time Jim, who was a country western fan, played a recording of Willie Nelsons “On the Road Again” over the radio as they took off from Palmdale headed for Singapore. So on the first flight of PAV-2 Jim got a call from Mission Control “Standby we have a special message for you” and over the radio came the strains of “On the road again”.

Did they do any dog fighting with other fighters? No, but Jim had to find out max sustained G at M=1.3 and 35K in Mil and AB power on both air vehicles. A couple of days later he was in an F-16 for proficiency and at 25K , M=0.85 he did the same test and the numbers were pretty close.

Yu Ping Lu.
RCS testing. .4 scale test model. The numbers were so good that the colonel did not believe them. He said you must have left something off the model like control gaps. So Yu Ping drove him out to Grey Butte, put him on the cherry picker and had him examine the model. “Colonel can you put your fingers in the control gaps?” and he had to admit that he could. 6db makes a difference of 50% detection range.

In the proposal Northrop was planning to include the RCS numbers predicted, projected and measured. The colonel told us that we did not have the experience and the model did not represent the true number so we had to take them out. The other team was given credit for the F-117 and they were checked up such that we were even, and they could not pick a winner. “We did much better”.

I observed one telling moment prior the event as a key flight controls engineer approached; both pilots spontaneously raised their arms and bowed down to him, so high was their regard for the excellence of the airplane as a flying machine.

 

[sferrin]

Interesting. I'd always heard that the F120 powered YF-23 was the faster of the two but apparently that is not the case. (PAV-1 was the F119 powered aircraft.)

"A chart shown with test results - number of flights, max speed (demonstrated) PAV-1 M=1.8 PAV-2 M=1.7, max angle of attack and max altitude about 50K feet. "


"The GE powered aircraft were slower than the Pratt planes and the YF-23 PAV-1 was faster than the YF-22 aircraft. The Air Force chose the slowest plane with the slowest engine! "

???

 

[bring_it_on]

I think it was a typo..Also I always thought a 12dB reduction in RCS results in 1/2 the range.. :-[

 

[kagemusha]

Thanks BillRo!

Interesting. I'd always heard that the F120 powered YF-23 was the faster of the two but apparently that is not the case.

Did you read this Paul Metz's presentation?

http://www.secretprojects.co.uk/forum/index.php/topic,1092.msg211876.html#msg211876

 

[Ogami musashi]

Thanks BillRo,


Were the graphics in the presentation similar to those?

78588500(atfdemval).pdf

PDF File

onedrive.live.com

 

[BillRo]

Yes, some of the charts were identical as far as I can remember; the briefing above is more comprehensive. I expect they were used since they had been cleared for public release.

 

[supacruze]

Guys, PAV-2 with the GE engines was not slower. That powerpoint presentation was sanitised. The top speed of PAV-2 and indeed PAV-1 is classified. They just put some generic figures in for that presentation. You have to understand that those people are living and working in a highly political environment and they are not going to say what they really think, you have to read between the lines. Its not a case of freedom of speech, these guys are muzzled. You have to do really thorough detective work to find what really happened. If you look up Edo and their involvement in the F-22 programme, you will get a clue. Another clue is the Air Force ATF evaluation committee was directly ordered not to make a recommendation, they were only allowed to give "stoplight colours" on various aspects of the performance criteria. I have been referred to a source on the net that claims that Donald Rice has since tacitly admitted that Northrop's design was better. My intuition is that he was bribed to choose Lockheed, but not necessarily by Lockheed. No matter how much you think you live in a free democracy, no one one is going to whistle-blow on this programme because they dont want to jeodardise their careers. Read between the lines.


I have updated my Lockheed page with new images...


http://yf-23.net/Lockheed.html

 

[fightingirish]

I went to the WMOF event today in Torrance and saw a bunch of my "old" Northrop colleagues; some came from as far away as the US East Coast and some that I hired from college were retired. PAV-2 was parked outside and both Paul Metz and Jim Sandberg were there and shared the presentation. The whole thing was video taped by the Palos Verdes couple who have done the rest and it will be available in a month. I thanked them for their efforts and told them how much the historical aviation community enjoys their work.

Attached are a few pix. I will pick up the previous threads and answer as many questions there that I can plus some I received separately. You will be able to get more precise answers when the video is released. I made a recording but I have not checked as to its quality yet.

Bill

Video:
https://www.youtube.com/watch?v=2EFHywoWzNQ

https://www.youtube.com/watch?v=2EFHywoWzNQ

YF-23 PAV2 First Flight and Walk Around by Test Pilot Jim Sandberg
Betty Wheaton interviews YF-23 PAV2 Test Pilot Jim Sandberg about the PAV2 first flight (landing gear problem), and Jim conducts a walk-around of the aircraft discussing typical checks he performed prior to a test flight. The YF-23 PAV2 is on display at the Western Museum of Flight. Produced by Jarel & Betty Wheaton for Peninsula Seniors www.pvseniors.org

B)

 

[fightingirish]

Next video:
https://youtu.be/iU8gWgz9n4U

https://youtu.be/iU8gWgz9n4U

YF-23 Walk Around and Design Features by Test Pilot Paul Metz
Betty Wheaton interviews YF-23 Test Pilot Paul Metz who conducts a walk around of the aircraft highlighting design features. YF-23 PAV2 is on display at the Western Museum of Flight. Produced by Jarel & Betty Wheaton for Peninsula Seniors www.pvseniors.org

Awesome video! B)
I especially enjoy how PAV2 got the nickname 'spider' with 'black widow hourglass' marking. ;D

 

[Colonial-Marine]

I have updated my Lockheed page with new images...
http://yf-23.net/Lockheed.html

I think the images of the Lockheed's "6th generation" concept with the comments about plagiarism are a bit unfair and unprofessional. In this industry everybody who survives tends to "borrow" from each other. More than anything it may reflect a subtle admittance that the F-23's balance of key characteristics was a better fit for the future than those of the F-22. Lockheed's work seems more in-line with views on aerial combat from the late '80s and '90s. Concepts like super-maneuverability were a big deal at the time and their ATF had a configuration including TVC to achieve that while Northrop forgo those in favor of greater stealth. Yet the value of super-maneuverability was much overrated in the face of continued air-to-air missile and situational awareness related developments.

 

[fightingirish]

Third video:

https://youtu.be/Vpkv1ErWIf8

YF-23 DEM/VAL Presentation by Test Pilots Paul Metz and Jim Sandberg
YF-23 DEM/VAL program presentation by YF-23 Test Pilots Paul Metz and Jim Sandberg commemorates the 25th anniversary of the first flight. Produced by Jarel & Betty Wheaton for Peninsula Seniors www.pvseniors.org

 

[Kryptid]

I have updated my Lockheed page with new images...
http://yf-23.net/Lockheed.html

I think the images of the Lockheed's "6th generation" concept with the comments about plagiarism are a bit unfair and unprofessional.

I agree. It's not like Northrop invented the concept of the V-tail: even the F-117 had it before the YF-23 did. Other than being stealthy and having two engines, that's pretty much the only thing the Lockheed 6th-gen concept has in common with the YF-23 anyway.

 

[lantinian]

Interesting. I'd always heard that the F120 powered YF-23 was the faster of the two but apparently that is not the case. (PAV-1 was the F119 powered aircraft.


"The GE powered aircraft were slower than the Pratt planes and the YF-23 PAV-1 was faster than the YF-22 aircraft. The Air Force chose the slowest plane with the slowest engine! "

???

You've heard right. The last slide of the presentation clearly shows the GE were faster.

I did a small graphical experiment.... assuming all values on the graph in the last slide were to scale and using the official values for the YF-22 supercruise speeds
See attachment.

YF-23 (P&W) - Mach 1.48
YF-23 (GE) - Mach 1.63

 

[Sundog]

I agree. It's not like Northrop invented the concept of the V-tail: even the F-117 had it before the YF-23 did. Other than being stealthy and having two engines, that's pretty much the only thing the Lockheed 6th-gen concept has in common with the YF-23 anyway.

The V-tail on the F-117 wasn't anything like the V-tail on the YF-23. The V-tail on the F-117 only operated in yaw, it was only subsonic, and it didn't have to operate with any where near the maneuvering capabilities of the YF-23. The tails on the YF-23 provided control in yaw, pitch and roll at both subsonic and supersonic parts of the envelope. That's a huge difference. Also, the V-tail goes back much further than the Lockheed-Martin F-117. It goes back to prewar days as a way to reduce drag. The first plane in large scale production, AFAIK, to use the v-tail is the Beechcraft Bonanza, and the tail on it operated in yaw and pitch.

The fact that the Lockheed design shown for the sixth gen model resembles the YF-23 merely indicates how advanced the YF-23 configuration was when compared to the YF-22. Stating such a fact isn't anything new, as it was something we understood twenty five years ago when we saw what both teams offered.

It's a well known fact that the YF-23 had the superior performance overall, when compared to the YF-22. But, as has been repeated often, the Air Force wanted to go the less risky route and was angry at Northrop's performance on the B-2, so they chose Lockheed Martin as the winner, since both designs met or exceeded the specs required by the ATF program.

 

[Stargazer]

It's a well known fact that the YF-23 had the superior performance overall, when compared to the YF-22. But, as has been repeated often, the Air Force wanted to go the less risky route and was angry at Northrop's performance on the B-2, so they chose Lockheed Martin as the winner, since both designs met or exceeded the specs required by the ATF program.

There is also a well-known urban legend whereby Northrop lost the contract only to be granted a contract for a secret development of it, supposedly the aircraft that crashed at Boscombe Down in 1994. If there was any amount of truth to that I guess we'd have seen more occurrences of that secret bird... unless of course the crash of a prototype killed the whole program before it got a chance to get operational.

 

[Steve Pace]

In my humble oppion I feel that the YF-22 was more agile, maneuverable than the YF-23. Nobody seems to address this. -SP

 

[BillRo]

Now that the videos from the YF-23 presentations have been released we can all be part of the event. Very little was edited out except for a couple of odd questions and Yu Ping Liu's words at the end. These are repeated from my earlier transcript of the joint presentation.

RCS testing. .4 scale test model. The numbers were so good that the colonel did not believe them. He said you must have left something off the model like control gaps. So Yu Ping drove him out to Grey Butte, put him on the cherry picker and had him examine the model. “Colonel can you put your fingers in the control gaps?” and he had to admit that he could. 6db makes a difference of 50% detection range.

In the proposal Northrop was planning to include the RCS numbers predicted, projected and measured. The colonel told us that we did not have the experience and the model did not represent the true number so we had to take them out. The other team was given credit for the F-117 and they were checked up such that we were even, and they could not pick a winner. “We did much better”.

 

[sferrin]

I have updated my Lockheed page with new images...
http://yf-23.net/Lockheed.html

I think the images of the Lockheed's "6th generation" concept with the comments about plagiarism are a bit unfair and unprofessional.

I agree. It's not like Northrop invented the concept of the V-tail: even the F-117 had it before the YF-23 did. Other than being stealthy and having two engines, that's pretty much the only thing the Lockheed 6th-gen concept has in common with the YF-23 anyway.

Hey, they're both gray. Seriously though, aside from the color and butterfly tails, they have nothing in common.

 

[Sundog]

In my humble oppion I feel that the YF-22 was more agile, maneuverable than the YF-23. Nobody seems to address this. -SP

There were parts of the envelope, especially at the low end, and a few parts of the supersonic envelope, where the YF-22 was more maneuverable, but the YF-23 met all of the maneuvering requirements without requiring TV and it wasn't that big of a difference.

 

[overscan (PaulMM)]

So the overall impression from Northrop guys perspective is -

Northrop did better on Stealth but that didn't get recognised by the USAF. Lockheed were trusted (due to in-service F-117) on understanding stealth while Northrop's design proposal was so stealthy it evoked disbelief and wasn't seen as achievable. Both proposals met the targets.
Northrop did better on Speed. Both proposals met the targets.
Northrop exceeded agility targets without using TVC. Lockheed had minor advantages in some areas of the envelope due to TVC. Both proposals met the targets.
The required avionics was very far beyond the 1986 state of the art. The LPI radar stuff was all brand new and more important, in innovation terms, than the airframes.
YF-23 was essentially a Northrop design. McDonnell-Douglas didn't really bring too much to the design. The Lockheed/General Dynamics/Boeing team did a better job of working collaboratively and integrating their relative strengths.
Lockheed did better in selling their proposal. DEV/VAL was supposed to just validate the proposals by showing they could meet predictions with real hardware for specific areas of interest. Northrop concentrated purely on demonstrating the things they needed to from a technical perspective, while Lockheed did some stuff that looked good and make good photographs.
Lockheed had just completed successful delivery of the F-117A on time, to specification, to point to while Northrop had just Tacit Blue and were in the middle of technical challenges with B-2.
Northrop had B-2 program already to do. Giving them ATF as well would be putting too much in one basket.

In the end both designs met the requirements. The USAF went with the safest option.

 

[lantinian]

In my humble oppion I feel that the YF-22 was more agile, maneuverable than the YF-23. Nobody seems to address this. -SP

To add to Sundog and Overscan points.
Lockheed had a showmanship as part of their proposal to win decision makers who did not have the background to understand the technical aspects of their proposal. The maneuvering showmanship wasn't evidence of better agility or maneuverability as explained by Paul Metz in the video above.

Paul Metz went to explain something I've also read in other books.
Both designs went after the same maneuvering requirement in 2 different ways. They also both exceeded them in different ways.

Lockheed went with the trust vectoring and standard sized horizontal stabilizers to get the necessary improvement.

Northrop chose to increase the aerodynamic surfaces by about 25% achieving the same control effect via aerodynamic force alone.

Lockheed decision is also a consequence of their very late redesign and essentially using the well matured middle and aft section of GD ATF proposal which came with trust Vectoring.
As such, Lockheed inherited the GD biggest design downside.... the need to have a vertical tail. With so little time to test its optimum size and location (both were changed for the EMD) Lockheed played it safe and made the vertical tails some 30% larger to make sure they will be effective at high AoA.

Northrop solved the vortex integration problem by early integrating vertical stabilizers with the horizontal into 1 control surface and achieving weight savings, lower drag and stealthier design.
They used some of those saving to implement the B-2 infrared signature reducing boat tail into the ATF as well.

Its very easy to overlook this fact but YF-23 used 100% of its larger tails control surfaces in both Pitch, Yall and Roll, while YF-22 TVC only works in pitch and the aircraft has to deal with its huge vertical tails stabilizing effect, inertial dead weight and drag when maneuvering. The YF-22 huge vertical tails design is essentially driven by narrow flight envelope regime both aircraft almost never get into, while the YF-23 tails are made to useful throughout its flight envelope.

Another thing that regular observers miss is how further away were YF-23 control surfaces relative to its center of gravity or longitudinal access of rotation.

As a result, while the TVC and huge vertical tails allowed the YF-22 to be controllable in post stall speeds at 60 AoA (great for airshow but arguably unusable in combat) in all other aspects of the flight envelope and, especially in Yall and Roll maneuvers, physics suggest the YF-23 has higher maneuvering power and lower maneuvering drag.

Lockheed 6 Gen "V tails + LO rear - trust vectoring" design is a testament to the forward looking nature of the YF-23 configuration and the correct definition of the "job to be done" by the Northrop team.

 

[bring_it_on]

Something from the late 80's..

McDonnell Fears Northrop's Image May Hurt ATF Bid