F-23A & NATF-23
For a very long time all but a very select few in the general public were completely in the dark about what Northrop's proposal for the production variant of the ATF might look like, although speculation and debate has been rife. Finally after 19 years, 2 official drawings were quietly released onto the Secret Projects forum by a couple of people calling themselves Mark and Overscan. The YF-23 fanbase was shocked. Here was a set of drawings showing precisely how the F-23A would have looked, complete with cross sections and interior detail. What was even more surprising was that these drawings were released before official drawings of the YF-23 prototype had been made public. The windfall was completely unexpected but it precipitated the final release of a comprehensive set of official drawings of the YF-23 PAV, bringing us very close to completion in terms if what is needed to accurately model these remarkable aircraft. In a twist of irony, what the new Northrop drawings revealed was that information on the F-23A had been sitting right under our noses all along, in the form of a 3 view diagram published by Koku Fan way back in the 1990's. There was a rumor that an illustration of the EMD configuration had accidentally been passed out to the public in a pamphlet during the rollout ceremony of PAV-1, and that when Northrop staff realised what had happened, they quickly went round the crowd trying to recover all the pamphlets that had been passed out. Evidently some pamphlets escaped, and this is what Koku Fan used as a basis for their diagram. This diagram has also appeared in an issue of the French magazine Air Action. Comparison of Koku Fan's illustration with the official Northrop drawings reveals that it was surprisingly accurate. More information on the
perspective view of official Northrop F-23A EMD configuration
Close examination of the F-23A drawings reveals that the shape was almost completely redesigned: only the wings and the canopy remained the same. The nose was enlarged to accept a radar, access panel lines were changed, the forebody chine line was raised level with the leading edge of the wing, the fuselage cross section was changed, and a second missile bay was added ahead of the main one. The sidewalls of the weapons bays were canted slightly to reduce radar signature. The gun installation changed sides. The fuselage was recontoured to accomodate the weapons bay changes, particularly towards the middle and rear resulting in reduced conformity to the Area Rule. The air intakes were completely transformed to resemble a cross between those of the SR-71 Blackbird and B-2 Spirit. The engines were realigned slightly to point inwards at the rear resulting in a thrust line 1.5 ° off centre. With the deletion of thrust reversal the nacelles were completely recontoured to more closely conform to the shape of the engine. The jet nozzle paddles looked much more like those used on the F-22A Raptor. The zig-zag line of the tail was cleaned up, eliminating 2 'zigs' and making a cleaner empennage. And finally the landing gear was beefed up: larger tyres are noticeably apparent. Overall length had increased from 67ft 6inches of the prototype to 70ft 5 inches, confirming Bill Sweetman's prediction, although wingspan remained the same.
F-23 RCS mockup
With the publication of Tony Landis' and Dennis Jenkin's book in 2008, details of the Radar Cross Section mockup were revealed for the first time. The side view published in this book shows the mockup to in fact be an early configuration of the EMD variant before the changes announced by the Programme Manager of the time, Thomas Rooney. The clues are in the shape of the foward fuselage and chine, which are longer than the YF-23. The chine of the RCS mockup is straight when viewed from the side, whereas the prototypes' chines kinked up to meet the leading edge of the wing. The configuration of this mockup shows that its design was frozen before the Air Force decided to drop the reverse thrust requirement. The nose is slightly different to the final EMD configuration and the trailing edge of the empenage matches the prototype configuration. Note also the distinctive Ferris-like camouflage scheme.
The view that revealed that the RCS mockup was indeed an initial configuration of the F-23 EMD variant rather than the YF-23 as previously thought. Note the distinctive camouflage scheme.
Almost 20 years after the first flight of the YF-23, we have yet another windfall magically appearing out of the blue: the public release of official drawings for Northrop's proposal for the Naval version of the ATF, termed NATF-23. These official drawings confirm previous speculation on internet forums that Northrop resorted to a canard layout to achieve a low enough landing speed for carrier operations. The rumor going round about 2-3 years ago was that the standard V-tail configuration required an angle of attack that resulted in the tail scraping on the deck. The drawings show what is nevertheless a radical solution which would have kept pace with trends in Europe and presented a dramatic and distinctive silhouette. The shape has been completely transformed from the F-23A configuration; nothing remains in common with the USAF variant except for the windscreen. First impressions lead to the conclusion that the radar signature would have been less stealthy than the USAF version. The very large canards would have created a blind spot in a critical area for pilots engaged in close range ACM. Information on this variant is now available for a nominal fee in eVolume 3 Number 2 of Aerospace Projects Review from Scott Lowther.
Perspective view of official Northrop NATF-23 configuration. This image was released to the general public for the first time ever in April 2010.
Last updated May 2015.
Northrop F-23A EMD Proposal Northrop F-23 ATF proposal Northrop F-23 production proposal Northrop F-23 production variant Northrop YF-23 production variant Northrop YF-23 production version Engineering Manufacturing Development Northrop YF-23 EMD Proposal Northrop NATF-23 Proposal Northrop naval YF-23 Northrop F-23 carrier version Northrop NATF Northrop Navy Advanced Tactical Fighter
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