Flightline: 122 - 1981 Advanced Tactical Fighter Program
In June of 1981, the USAF began the ATF program, seeking a new fighter to challenge the USSR’s new Su-27 and MiG-29 designs.
The Air Force was interested in incorporating new technologies into the design, including composite materials, advanced fly-by-wire and glass cockpits, low-observable/stealth ideas, STOL (short-takeoff and landing) and supercruise (achieving Mach speeds without afterburner). By 1984, requirements had settled down to a maximum T/O weight of 50,000 lbs, a mission radius of 800 mi, a supercruise speed of Mach 1.4 to 1.5, and a 2,000 foot take-off run. A separate program, the Joint Advanced Fighter Engine, was released to P&W and GE to develop a new engine for the ATF. A requirement for air-to-surface missions was later spun off into the Joint Strike Fighter program, which resulted in the X-32 and X-35 competition and eventually the F-35 Lightning II.
Northrop responded with three concepts, the P-900 (also called the Co-op fighter), the Missileer, and Agile, which was based on an earlier design co-developed with Dornier for an aborted fighter program for the Federal Republic of Germany (which later became the Eurofighter Typhoon).
Artists’ Impression of the P-900. | Illustration: Northrop
Internals and projected specifications of the P-900. | Illustration: Northrop
The P-900 was a tiny thing, barely 17,000 lbs and just over 47 feet long. The pilot was seated in a steeply inclined ejection seat; Northrop having clearly expected the design to be highly maneuverable. A modular, retractile weapons bay was fitted to the ventral side, allowing the carriage of up to four guided air-to-air missiles, a combination of guided and unguided missiles and a gun, or a gun and anti-tank missiles.
The modular weapons bay of the P-900 design. | Illustration: Northrop
The N-357 Missileer design is less documented, a single image showing a semi-tailless design with diamond-shaped wings; clearly an ancestor of the YF-23. Of note is the retractable missile tray and over-the-shoulder intakes:
“Agile”, while clearly drawing from the ND-102 concept, also apparently draws from the Northrop YF-17:
A render of the Northrop/Dornier ND-102. | Illustration: Northrop/Dornier
Artists’ impression of the “Agile” ATF concept. | Illustration: Northrop
McDonnell Douglas advanced two concepts, ATF #4 was optimized for transonic speed and high alpha maneuvering, but seemingly offered nothing new over McDonnell Douglas’ F-15.
McDonnell Douglas ATF concept #4. The F-15 influence is strong here. | Illustration: McDonnell Douglas
McD’s second design, numbers 17 and 18, were for the ATF's air-to-surface requirement (later dropped), and differed only in the configuration of the intakes. This design does seem to have more stealth baked in, though the rudders would need to have been canted over.
Concept #17-18, supposedly optimized for air-to-surface attack, shown firing AAMs. | Illustration: McDonnell Douglas
Rockwell’s concept #5 was roughly equivalent to the Eurofighter Typhoon, featuring a tailless canard design optimized for transonic maneuvering, and included thrust vectoring.
Concept #5 would have had limited stores and fuel capacity. | Illustration: Rockwell
Rockwell’s other design, Concept #6, was a larger, more stealthy entry projected to have maneuverability comparable to the Su-27.
Concept #6. | Illustration: Rockwell
Boeing submitted three designs, two air-to-air concepts and one for strike. Concepts Seven and Eight differed only in wing-shape, with 7 being optimized for high-alpha maneuvering and transonic flight, while 8 featured a double-delta wing.
Boeing Concept #7, referred to as the Model 908 internally . | Illustration: Boeing
Concept #8, aka Model 985. | Illustration: Boeing
Boeing’s concept 15 was submitted for the strike mission, and featured a low-mounted swing-wing and thrust vectoring.
An early illustration of Concept 15. | Illustration: Boeing
A later version of #15, with the intakes moved over-the-shoulder, twin tails, and more smoothing. | Illustration: Boeing
A completely different model was submitted when the requirements were updated:
Display model of Boeing's updated design. | Photo: Boeing/LockMart
Illustration of the new concept, with missiles in firing position. | Illustration: Boeing/LockMart
Grumman, eager little overachievers that they were, submitted four entries, three for air-to-air and one for strike. Concept 9 had canards, forward-swept & tails, and thrust vectoring. Drop that thing into any sci-fi setting and it’s right at home. Concept 10 kept the same fuselage, but switched to swept wings. If you told me that it had GERWALK and Battloid modes, I would not doubt you. A later revision of this concept had twin tails. Concept 11 used the same planform, but was projected to be heavier. Concept 13 was the ATS version, and was more or less a refinement of concepts 10 and 11, only heavier. Again, the final version had twin tails.
Artist’s impression of Grumman Concept #9. | Illustration: Grumman Co.
Wind tunnel model of Concept 10 . | Photo: NASA/Grumman
Concept 10 wind tunnel model, with human for scale . | Photo: NASA/Grumman
Display model of Concept 13, the strike fighter version. | Photo: Grumman Corp.
For the RFI stage, Lockheed basically said “Hey, you know what would be good? Son of YF-12!” These designs were absolute units, weighing between 114,000 and 116,000 pounds. Obviously not dog-fighters, these were envisioned as long range interceptors in the mold of the original F-12, the F-14 and the MiG-25/31. Likely they would have been launching GAR-9/AIM-47 missiles as well....
By the time of the revised ATF proposals, Lockheed had drawn on its experience with stealth/low-observable tech from the Blackbirds, Have Blue and F-117 and produced a rather polished fighter concept:
Lockheed graphic showing the initial ATF concepts that led to their 1986 submission. | Illustration: Lockheed Aeronautical Systems
It’s interesting to see how much of the eventual F-22 is there already, and it's even more interesting to note that this design was initially rejected, then revived in the YF-22.