Northrop Advanced Projects (AP-) designations

[Mr London 24/7]

Maybe it's just me - but I was previously unaware of the designation AP-1?:

Since joining Northrop Grumman in 1976, Mr. Williams'.... contributed to the design and development of.... AP-1 Tacit Blue low observable technology demonstrator....

(http://www.dau.mil/conferences/presentations/2004_PEO_SYSCOM/biographies/williams.html)

By the time the F-117A entered service, Northrop was flying the AP-1 Tacit Blue

(http://www.airspacemag.com/military-aviation/stealth.html?device=ipad)

 

[Stargazer]

Interesting. However, let's keep in mind that all the B-2 bombers have an AV- number (starting with AV-1), so "AP-1" might simply indicate that this was the first (and incidentally the only) airframe of that model.

 

[TomS]

The B-2's AV sequence numbers do not identify a specific aircraft model-- AV just stands for Air Vehicle, and is pretty widely used. I don't know of anyone using AP in the same way. OTOH there is at least one official reference to AP-1 as a project or type designation for Tacit Blue:


http://www.dau.mil/conferences/presentations/2004_PEO_SYSCOM/biographies/williams.html

[Thomas L. Williams] has held numerous senior level program and technical management positions within Northrop Grumman and contributed to the design and development of the Navy's F/A-18 Hornet strike fighter, F-20 Tigershark, AP-1 Tacit Blue low observable technology demonstrator, YF-23 Advanced Technology Fighter prototype, and B-2 stealth bomber.

[Note: this is the same link Mr London posted, but I think the quote is clearer.]

Northrop did have an Advanced Projects division akin to the Skunk Works, so I'd guess AP-1 means the first aircraft type by that group (at least in that numbering sequence).

 

[Stargazer]

Thanks for the tip, TomS. A search on the web brought the following result, which concurs with what you said:

SHARC aka Shark

As stated, SHARC is related to the YF-23. However, SHARC was an earlier design, and the YF-23 design was derived from it, though scaled-up and twin engined. Northrop design, Advanced Project (AP-2), begun August 1978, was for an advanced fighter to accompany Tacit Blue on missions. Late 70s/early 80s, Northrop RCS testing involved several different models of different designs - Hawk (ATB/AP-4/& 10), Manta, Whale (AP-1 / aka Shamu / Tacit Blue), and Shark (AP-2).

The name "Shark" sounds similar to the acronym SHARC, as tested by NASA Langley. However, Shark is the name Northrop personnel gave the design. Shark was a follow-on to the F-20 Tigershark. Shark/AP-2 was proposed to the USAF in 1978. Its more formal title was "Light Co-operative Fighter" or LCF. It was in the 17,000-lb class, powered by one GE F404 engine. Supersonic, but less than Mach 2.

In 1981, when the ATF program (Senior Sky) began, Northrop was in a good position to present the USAF with an excellent proposal. As reported in AW&ST, June 1, 1981 issue, (though not in exact words), stated thusly: "Northrop is building a fighter-size stealth aircraft that will fly soon; based a design proposed to the USAF." This was Shark, and is reported to have flown at Groom in late summer 1981. About the size of Have Blue, but heavier. Code name of program was Tacit ____

Note on the four NASA langley photos of SHARC/Shark that the photo ID and date are censored out. The program for the most part is still classified, semi-black.

Source: http://www.dreamlandresort.com/forum/messages/8373.html

I know that what this website publishes is often to be taken with a pinch of salt, but in this case the information seems plausible.

 

[quellish]

Thanks for the tip, TomS. A search on the web brought the following result, which concurs with what you said:

SHARC aka Shark

As stated, SHARC is related to the YF-23. However, SHARC was an earlier design, and the YF-23 design was derived from it, though scaled-up and twin engined. Northrop design, Advanced Project (AP-2), begun August 1978, was for an advanced fighter to accompany Tacit Blue on missions. Late 70s/early 80s, Northrop RCS testing involved several different models of different designs - Hawk (ATB/AP-4/& 10), Manta, Whale (AP-1 / aka Shamu / Tacit Blue), and Shark (AP-2).

The name "Shark" sounds similar to the acronym SHARC, as tested by NASA Langley. However, Shark is the name Northrop personnel gave the design. Shark was a follow-on to the F-20 Tigershark. Shark/AP-2 was proposed to the USAF in 1978. Its more formal title was "Light Co-operative Fighter" or LCF. It was in the 17,000-lb class, powered by one GE F404 engine. Supersonic, but less than Mach 2.

In 1981, when the ATF program (Senior Sky) began, Northrop was in a good position to present the USAF with an excellent proposal. As reported in AW&ST, June 1, 1981 issue, (though not in exact words), stated thusly: "Northrop is building a fighter-size stealth aircraft that will fly soon; based a design proposed to the USAF." This was Shark, and is reported to have flown at Groom in late summer 1981. About the size of Have Blue, but heavier. Code name of program was Tacit ____

Note on the four NASA langley photos of SHARC/Shark that the photo ID and date are censored out. The program for the most part is still classified, semi-black.

Source: http://www.dreamlandresort.com/forum/messages/8373.html

I know that what this website publishes is often to be taken with a pinch of salt, but in this case the information seems plausible.

http://www.secretprojects.co.uk/forum/index.php?topic=1748.0

Images DSC000040001.JPG, #4 AX (right), SOF(left).jpg, #2 MRF_RFI (ALF)-2.jpg, etc.

 

[Stargazer]

I have split this discussion from the TACIT BLUE thread, because it added an undesirable speculative element in that topic and also because it belongs in this section. But most of all, because the excellent Radioplane/Northrop-Ventura listing provided recently by Mark Nankivil contains quite an interesting entry with regards to the AP- subject:

Date: February 11, 1982
NV-150
AP-3 Vehicle
Dr. Howard

This ties in nicely with Dreamlandresorts's allegations (see posts above) that there were AP-1, AP-2 and AP-4. The series would have consisted of sub-scale proof-of-concept vehicles.

In this case, there would have been at least 4 prototypes in this Advanced Projects series:

• AP-1 — Whale or "Shamu" — TACIT BLUE demonstrator — work begun 1978 — flown February 1982.
  More: http://www.secretprojects.co.uk/forum/index.php?topic=278.0
  
• AP-2 — Shark (SHARC) — LCF/ATF demonstrator — work begun 1978 — flown late Summer 1981.
  More: http://www.secretprojects.co.uk/forum/index.php/topic,373.0
  and http://www.secretprojects.co.uk/forum/index.php/topic,1748.0.html
  
• AP-3 — unidentified vehicle — presumably unmanned (as it was a Ventura Division product) — flown circa 1982?
  
• AP-4 — Hawk— ATB demonstrator — flown?Nothing here to purport the existence of this one.
  The ATB topic is here, though: http://www.secretprojects.co.uk/forum/index.php/topic,214.0

Note also that Dreamlandresorts mentions another program in the same list called Manta.
Although the evidence is slim, it could be the project described here:

http://www.secretprojects.co.uk/forum/index.php/topic,3928.msg201817.html#msg201817

 

[overscan (PaulMM)]

To add to the in-fighting, Northrop have proposed an ultra cheap, highly accurate stealthy cruise missile, the NV-150, as a substitute for the T-16/T-22. The NV 150, powered by a Williams International turbofan and equipped with a ring laser gyro aided by a satellite navigation system, is apparently highly accurate with over 200 nm range. The cost per unit was suggested at $300,000, low enough to provoke the USAF into disrupting the T-16/T-22 development program. One can have no doubts that the program will eventually stabilise, as the USAF and Army are determined to acquire their respective weapon systems [Editor's note 2005: this project became the AGM-137 TSSAM, later cancelled and replaced by the AGM-158 JASSM].

http://www.ausairpower.net/TE-Assault-Breaker.html


Wolfbane is one of the most notorious posters on Dreamlandresorts, wrong many times, so I'd definitely take that post with a pinch of salt.

Not sure if Carlo Kopp is right to join NV-150 to TSSAM. Aim9xray was pretty sure it wasn't a Ventura design. NV-150 / AP-3 was however a Northrop cruise missile proposal of the early 80s.

 

[BillRo]

Correct me if I am wrong, but I am pretty sure AP-3 was Tacit Rainbow.

 

[overscan (PaulMM)]

Thanks Bill, moved your post here to where we are discussing AP- designations. Tacit Rainbow looks more like a Ventura product than TSSAM, certainly.

 

[BillRo]

Although I got to the program when we were doing production design under the Tacit Rainbow designation, several old-timers referred to it as AP-3.

 

[overscan (PaulMM)]

I believe Tacit Blue involved Northrop Ventura as well? They also led the early cruise missile work that led to it. (http://www.northropgrumman.com/Capabilities/B2SpiritBomber/Documents/pageDocuments/B-2-Spirit-of-Innovation.pdf)


If so, then AP- might resolve itself to a Ventura designation system.

 

[Stargazer]

If so, then AP- might resolve itself to a Ventura designation system.

Not quite. The Shark obviously would not fit in.

 

[Stargazer]

Although I got to the program when we were doing production design under the Tacit Rainbow designation, several old-timers referred to it as AP-3.

Very interesting. The PDF list posted by Mark Nankivil describes the NV-138 as a "Low Cost Tactical Target Drone". That specification evolved to become "Advanced Low-cost Anti-Radiation Missile", which was the TACIT RAINBOW program.

Until now I assumed that TACIT RAINBOW was also the NV-138 because of a previous post on this forum by one-time poster kpkatz:
http://www.secretprojects.co.uk/forum/index.php/topic,11208.msg166809.html#msg166809

However, it is very possible that the program started as NV-138 when it was the "Low Cost Tactical Target Drone" and then evolved into the NV-150 (AP-3) when it became the "Advanced Low-cost Anti-Radiation Missile". Date-wise it would also make a lot more sense.

 

[overscan (PaulMM)]

If so, then AP- might resolve itself to a Ventura designation system.

Not quite. The Shark obviously would not fit in.

AP-1 and AP-3 are the only confirmed designations outside of that single post by a known fantasist (Wolfbane). AP-2 cannot be "SHARC" - it is wrong timingwise (1990s) and SHARC wasn't a Northrop project as "Sharcmaster" confirmed, its a Air Force Wright Aeronautical Laboratory (AFWAL) project with NASA Ames.

http://www.secretprojects.co.uk/forum/index.php?topic=373

The origin of the FLAC (SHARC) concept came from an aircraft designer from the Flight Dynamics Lab’s Mission Analysis and Design Group. The Designer was given a set of requirements to come up with an advanced fighter concept that had stealth qualities.

Since this FLAC program/design came out just as the F-22 had just won the Advanced Tactical Fighter (ATF) competition, and it was generally known that whatever went into the 40x80 usually ended up in Aviation Week. Knowing this the USAF FLAC Team was very sensitive to the design NOT even closely resembling the F-22

IF (big if) there was a subscale, unmanned ATF and/or ATB demonstrator in early 80s, it *might* have been built by Northrop Ventura division for NAC (Hawthorne) as Ventura were the unmanned drone specialists.

 

[Stargazer]

Yes, Paul. I won't dispute your arguments. However the author of that post explained that Northrop's Shark was originally devised to an earlier LCF specification (circa 1979) and THEN, when the demonstrator was about to be ready, was suggested as a basis for ATF (circa 1982). At least that's the way I understand it. I'm not saying this is true, just trying to put things in perspective.

IF (big if) there was a subscale, unmanned ATF and/or ATB demonstrator in early 80s, it *might* have been built by Northrop Ventura division for NAC (Hawthorne) as Ventura were the unmanned drone specialists.

Yes. After all there's GOT to be something sufficiently hush-hush behind the missing NV- designations...

 

[overscan (PaulMM)]

Yes, Paul. I won't dispute your arguments. However the author of that post explained that Northrop's Shark was originally devised to an earlier LCF specification (circa 1979) and THEN, when the demonstrator was about to be ready, was suggested as a basis for ATF (circa 1982). At least that's the way I understand it. I'm not saying this is true, just trying to put things in perspective.

1982 is too early to be SHARC by a decade or so. Wolfbane has seen a pic of SHARC, seen a general resemblance to YF-23, and invented a back story for it. Maybe there was a Northrop Ventura "Shark" in 1982 that Wolfbane had information on - not everything he posted is total fabrication - and he assumed SHARC = Shark but it wasn't anything to do with the Wright-Patterson SHARC program.

 

[Stargazer]

1982 is too early to be SHARC by a decade or so. Wolfbane has seen a pic of SHARC, seen a general resemblance to YF-23, and invented a back story for it. Maybe there was a Northrop Ventura "Shark" in 1982 that Wolfbane had information on - not everything he posted is total fabrication - and he assumed SHARC = Shark but it wasn't anything to do with the Wright-Patterson SHARC program.

Oh, okay. My bad. I figured SHARC was earlier than that, thought it actually pre-dated the YF-23A demonstrators.

 

[BillRo]

Northrop Ventura was a Division of Northrop Aircraft so people went back and forth between the organizations - NV was at Newbury Park about 45 miles N of Hawthorne, home of Northrop Aircraft. I think it was used as a training ground for future Aircraft Div. General Managers and it was a really good place to work. AP was used for "black' programs at Aircraft not at Ventura Div. even though the Tacit Rainbow program was worked there. TSSAM was strictly Aircraft Div.

There is no evidence of a sub-scale (unmanned) B-2 demonstrator and I am sure that if there was, it would have been mentioned in the recently released B-2 book by Rebecca Grant. If there had been such a thing it would not have been done at Ventura since they would not have had the space or capabilities. Aircraft would have tapped them for their people's expertise as required.

 

[Stargazer]

Thanks a lot Bill! Both the info and the chronology are great and really helpful!

 

[kpkatz]

The posted source document for RP designations is like the Rosetta Stone of our field.

It also convinces me that NV-138 was in fact Tacit Rainbow. Judging from the latest date in the document, it was written in 1982. To support my belief (aside from 25+ year old memories that NV-138 was Tacit Rainbow):

• A program start date of 1979 would make sense for a missile that had its first flight in 1984 (if I recall correctly).
• The "Low Cost" part of the name would be in accordance with the Tacit Rainbow design philosophy that used some commercial standard electronics and sheet molding compound to lower costs.
• NV-150 definitely was not Tacit Rainbow. I think that it was a precursor to TSSAM, which I assume did not have a NV designation because it was an Aircraft Division design.
• The military designation AGM-136A was not yet assigned to Tacit Rainbow in 1982, when I assume this document was written.

Although I got to the program when we were doing production design under the Tacit Rainbow designation, several old-timers referred to it as AP-3.

Very interesting. The PDF list posted by Mark Nankivil describes the NV-138 as a "Low Cost Tactical Target Drone". That specification evolved to become "Advanced Low-cost Anti-Radiation Missile", which was the TACIT RAINBOW program.

Until now I assumed that TACIT RAINBOW was also the NV-138 because of a previous post on this forum by one-time poster kpkatz:
http://www.secretprojects.co.uk/forum/index.php/topic,11208.msg166809.html#msg166809

However, it is very possible that the program started as NV-138 when it was the "Low Cost Tactical Target Drone" and then evolved into the NV-150 (AP-3) when it became the "Advanced Low-cost Anti-Radiation Missile". Date-wise it would also make a lot more sense.

 

[Stargazer]

The posted source document for RP designations is like the Rosetta Stone of our field.

It also convinces me that NV-138 was in fact Tacit Rainbow. Judging from the latest date in the document, it was written in 1982. To support my belief (aside from 25+ year old memories that NV-138 was Tacit Rainbow):

• A program start date of 1979 would make sense for a missile that had its first flight in 1984 (if I recall correctly).
• The "Low Cost" part of the name would be in accordance with the Tacit Rainbow design philosophy that used some commercial standard electronics and sheet molding compound to lower costs.
• NV-150 definitely was not Tacit Rainbow. I think that it was a precursor to TSSAM, which I assume did not have a NV designation because it was an Aircraft Division design.
• The military designation AGM-136A was not yet assigned to Tacit Rainbow in 1982, when I assume this document was written.

Although I got to the program when we were doing production design under the Tacit Rainbow designation, several old-timers referred to it as AP-3.

Very interesting. The PDF list posted by Mark Nankivil describes the NV-138 as a "Low Cost Tactical Target Drone". That specification evolved to become "Advanced Low-cost Anti-Radiation Missile", which was the TACIT RAINBOW program.

Until now I assumed that TACIT RAINBOW was also the NV-138 because of a previous post on this forum by one-time poster kpkatz:
http://www.secretprojects.co.uk/forum/index.php/topic,11208.msg166809.html#msg166809

However, it is very possible that the program started as NV-138 when it was the "Low Cost Tactical Target Drone" and then evolved into the NV-150 (AP-3) when it became the "Advanced Low-cost Anti-Radiation Missile". Date-wise it would also make a lot more sense.

Thanks a lot kpkatz for returning to this topic and sharing your thoughts and memories about this subject!

 

[quellish]

Yes, Paul. I won't dispute your arguments. However the author of that post explained that Northrop's Shark was originally devised to an earlier LCF specification (circa 1979) and THEN, when the demonstrator was about to be ready, was suggested as a basis for ATF (circa 1982). At least that's the way I understand it. I'm not saying this is true, just trying to put things in perspective.

1982 is too early to be SHARC by a decade or so. Wolfbane has seen a pic of SHARC, seen a general resemblance to YF-23, and invented a back story for it. Maybe there was a Northrop Ventura "Shark" in 1982 that Wolfbane had information on - not everything he posted is total fabrication - and he assumed SHARC = Shark but it wasn't anything to do with the Wright-Patterson SHARC program.

I've now seen from multiple sources that AP-2 was a fighter design, evolved from TACIT BLUE, that eventually evolved into the YF-23. Did not resemble "SHARC" at all. It was not built and did not fly, it was an internal design exercise applying the TACIT BLUE / ATB LO technologies to a fighter.

Drawings have been published in the open before. Imagine the Scaled 401 with less span, and a nose that looks like a set of stairs.

 

[overscan (PaulMM)]

AWST actual quote is:

Lockheed has developed the design for a fighter-sized Stealth aircraft and is flying a technology demonstration aircraft in the fighter category against Soviet and simulated Soviet surface-to-air missile system radars.

Stealth Technology

Lockheed would team with Rockwell in building an actual bomber aircraft based on Stealth technology. Both companies have designs that take advantage of a low radar cross-section based on aeronautical characteristics, the use of radar-absorbent materials and application of electronic counter-measures (ECM) technology. The combination makes it difficult for ground-based air defense radars to detect the bomber and all but impossible for the tracking radars to locate the target within the radar beam, according to Pentagon officials.

The second industry team also briefed Weinberger and his deputies late last week. Thomas Jones, chairman of the board of Northrop, and T. A. Wilson, chairman of the board and chief executive officer of Boeing, presented cost and schedule information on the advanced technology bomber that the two companies would team to build.

Northrop is building a fighter-sized Stealth aircraft that is expected to fly soon, according to Pentagon officials, based on a design proposed by the company. Neither of the teams have constructed or flown an aircraft or aerodynamic test vehicle approaching the actual size of an advanced technology bomber, the Pentagon officials confirmed.

In June 1981, this can only mean the TACIT BLUE (first flight 5 February 1982, Length: 55.8 feet). The idea that they were about to fly a fighter prototype is clearly a complete invention by Wolfbane.

Additionally, according to Tony Chong, AP- numbers were allocated randomly to disguise when specific programs were initiated.

 

[quellish]

Yes, Paul. I won't dispute your arguments. However the author of that post explained that Northrop's Shark was originally devised to an earlier LCF specification (circa 1979) and THEN, when the demonstrator was about to be ready, was suggested as a basis for ATF (circa 1982). At least that's the way I understand it. I'm not saying this is true, just trying to put things in perspective.

1982 is too early to be SHARC by a decade or so. Wolfbane has seen a pic of SHARC, seen a general resemblance to YF-23, and invented a back story for it. Maybe there was a Northrop Ventura "Shark" in 1982 that Wolfbane had information on - not everything he posted is total fabrication - and he assumed SHARC = Shark but it wasn't anything to do with the Wright-Patterson SHARC program.

I've now seen from multiple sources that AP-2 was a fighter design, evolved from TACIT BLUE, that eventually evolved into the YF-23. Did not resemble "SHARC" at all. It was not built and did not fly, it was an internal design exercise applying the TACIT BLUE / ATB LO technologies to a fighter.

Drawings have been published in the open before. Imagine the Scaled 401 with less span, and a nose that looks like a set of stairs.

Note there is a photo of AP-2 in model form on page 23 of the Paul Metz book.

 

[overscan (PaulMM)]

The design in question is very clearly an evolution of the TACIT BLUE shape. Not seen it published before.

According to the book:

In 1978, Black World innovators Irv Waaland and John Cashen informally identified 12 military LO Advanced Project (AP) predictions for future stealth uses. These included bombers, fighters, cruise missiles, etc.

So it appears the AP- sequence AP-1 to AP-12 was all allocated simultaneously in 1978 for different roles.

 

[Empire]

 

[Sundog]

I never thought about it until now, but it's wing is just a smaller low aspect ration of the B-2 wing. I can also see that stepped chine as a stepping stone to the Christmas fighter (USF) design.

 

[Cancerman]

The design in question is very clearly an evolution of the TACIT BLUE shape. Not seen it published before.

According to the book:

In 1978, Black World innovators Irv Waaland and John Cashen informally identified 12 military LO Advanced Project (AP) predictions for future stealth uses. These included bombers, fighters, cruise missiles, etc.

So it appears the AP- sequence AP-1 to AP-12 was all allocated simultaneously in 1978 for different roles.

When I left in 95'. we were past AP21. They jumped around, program wise. Some were in house studies, some were outside funded. Things changed configuration and shape wise very rapidly based on results and direction of technology.

 

[quellish]

From Oral history interview with John Cashen. Second Interview., 25 April 2014, Aerospace Oral History Project, The Huntington Library, San Marino, California. :

WESTWICK: Can you give any examples?

CASHEN: I prefer not, only because I don't know where those stand. That was one thing. The other thing was that I became personally convinced that there was no justification for another stealthy airplane, that the Soviet IADS was a main reason for stealth, and if they're no longer an evolving threat, then why do you need new stealth aircraft. Recall at this point in time the F-22 is going ahead, along with the B-2. So I started thinking about retiring, and ultimately I did. I retired in early '93, convinced that there'd never be another stealthy aircraft. And then what happens? The UAV disease hits in the late ‘90s, and all of a sudden there's plenty of reason for stealth. That's what I work on today. Now, YF-23 started in Advanced Projects. We started in 1978. Steve Smith went to the whiteboard in his office with me and Irv, and he said, "What's the future of this stealth business?" We set up a numbering system, which is still used today at Northrop, where we identify system capability by these numbers. It was an internal numbering system, like the N327. Well, we called them APs. AP1 was Tacit Blue. There was one for a bomber. We didn't know what it was, but we had one for a bomber; we had one for what we thought was going to be the competition with Lockheed for what was to become the 117; we had the reentry vehicle for the Assault Breaker weapon concept; you name it, we had one for nine different concepts. AP3 was a fighter, an Advanced Technology Fighter. So in '78 we started an internal ATF design program.

Note this is from Cashen's memory decades after the fact. He says 9 ideas and AP-3 was the fighter that became ATF - he is likely mistaken. Interesting nonetheless.

 

[kmrumble]

Memory is fallible, but some of the confusion may arise from the possibility that there was at least one re-numbering of Northrop's advanced projects. When the Pico Rivera facility opened, I was told that all SPO visitors would have to get a new permanent picture badge issued instead of visitor's badges. On my next visit, the contracts manager took me down to the security office to help me through the process. When the badge was finished, I noticed that there was a matrix of numbers on the front, and that 5 and 10 were marked on mine. I inquired about the meaning, and was told that it meant I was cleared for AP-5 and AP-10, Tacit Blue and Senior Cejay. Then he said, "but they used to be different numbers, 1 and 6, I think. We re-numbered them when we started Advanced Systems Division in 1982." Forty-plus year old hearsay, so take it with a grain of salt.

 

[hesham]

View attachment 679968

What is this book ?.

 

[aim9xray]

The YF-23 Advanced Tactical Fighter by Paul Metz, published by Steve Ginter Books.

 

[Hydroman]

When I left in 95'. we were past AP21. They jumped around, program wise. Some were in house studies, some were outside funded. Things changed configuration and shape wise very rapidly based on results and direction of technology.

And I think YF-23 was AP-29.

 

[youyoyotoo]

AP-1 and AP-3 are the only confirmed designations outside of that single post by a known fantasist (Wolfbane). AP-2 cannot be "SHARC" - it is wrong timingwise (1990s) and SHARC wasn't a Northrop project as "Sharcmaster" confirmed, its a Air Force Wright Aeronautical Laboratory (AFWAL) project with NASA Ames.

http://www.secretprojects.co.uk/forum/index.php?topic=373





IF (big if) there was a subscale, unmanned ATF and/or ATB demonstrator in early 80s, it *might* have been built by Northrop Ventura division for NAC (Hawthorne) as Ventura were the unmanned drone specialists.

And I think YF-23 was AP-29.

in 1988, among many projects at Northrop Newbury Park (including Tacit Rainbow)we also had AP-9.

 

[overscan (PaulMM)]

AP-1 - Tacit Blue (before 1982 renumbering)
AP-2 - Pre-ATF Stealth Fighter
AP-3 - Tacit Rainbow
AP-5 - Tacit Blue (post 1982 renumbering)
AP-6 - Senior Cejay / ATB (before 1982 renumbering)
AP-7 - Possibly Northrop Newbury Park (Ventura) UAV
AP-9 - Unknown Northrop Newbury Park (Ventura) design
AP-10 - Senior Ceejay ATB (post 1982 renumbering)
AP-21 - "Passed AP-21 by 1995"
AP-29 - YF-23?

 

[overscan (PaulMM)]

There's also the DP- sequence - https://www.secretprojects.co.uk/threads/northrop-dp-designations.27708/

 

[quellish]

AP-1 - Tacit Blue (before 1982 renumbering)
AP-2 - Pre-ATF Stealth Fighter
AP-3 - Tacit Rainbow
AP-5 - Tacit Blue (post 1982 renumbering)
AP-6 - Senior Cejay / ATB (before 1982 renumbering)
AP-9 - Unknown Northrop Newbury Park design
AP-10 - Senior Ceejay ATB (post 1982 renumbering)
AP-21 - "Passed AP-21 by 1995"
AP-29 - YF-23?

AP-7 may have been a 1983 UAV run out of Ventura, never built

 

[Stargazer]

AP-1 - Tacit Blue (before 1982 renumbering)
AP-2 - Pre-ATF Stealth Fighter
AP-3 - Tacit Rainbow
AP-5 - Tacit Blue (post 1982 renumbering)
AP-6 - Senior Cejay / ATB (before 1982 renumbering)
AP-7 - Possibly Northrop Newbury Park (Ventura) UAV
AP-9 - Unknown Northrop Newbury Park (Ventura) design
AP-10 - Senior Ceejay ATB (post 1982 renumbering)
AP-21 - "Passed AP-21 by 1995"
AP-29 - YF-23?

I had AP-4 and AP-10 for SENIOR CEEJAY, not AP-6/AP-10... Also I have the name "Hawk" for them, is it in error?

 

[kmrumble]

I had AP-4 and AP-10 for SENIOR CEEJAY, not AP-6/AP-10... Also I have the name "Hawk" for them, is it in error?

AP-6 is correct. I never heard the word "Hawk" associated with the program. And only one E in Cejay, by the way.

 

[Hydroman]

AP-1 - Tacit Blue (before 1982 renumbering)
AP-2 - Pre-ATF Stealth Fighter
AP-3 - Tacit Rainbow
AP-5 - Tacit Blue (post 1982 renumbering)
AP-6 - Senior Cejay / ATB (before 1982 renumbering)
AP-7 - Possibly Northrop Newbury Park (Ventura) UAV
AP-9 - Unknown Northrop Newbury Park (Ventura) design
AP-10 - Senior Ceejay ATB (post 1982 renumbering)
AP-21 - "Passed AP-21 by 1995"
AP-29 - YF-23?

AP-21 I'm pretty sure was our ATA contender?