Area 51/Groom Lake Research Project, page 6

1.Performance
Both aircraft apparently met the USAF's performance specs. Northrop were a bit faster, longer ranging and stealthier, whereas Lockheed were a bit more manoeuvrable. It appears that the performance margins between both types were not dramatic.

The GE engine performed somewhat better in the trials than the P&W engine, but the final P&W proposal included an enlarged fan and hence higher thrust for production aircraft, presumably equalising the difference.

2.Price
Apparently Lockheed and P&W were cheaper, by how much does not appear to have been published anywhere (anybody know ?)

3.Development Risk
Northrop were penalised in a number of areas. Firstly Lockheed did more aggressive flying (played their politics right by doing it very visibly) during the dem/val program and demoed high AoA manoeuvres and missile launches well in excess of nominal dem/val requirements.

Secondly Lockheed built a very conservative airframe design with very conservative materials, ie an F-15/F-18ish almost hybrid planform geometry using a lot of aluminium and titanium alloys, unlike Northrop who opted for cca 50% empty weight in composites, using a very stealthy airframe geometry, never used before in a fighter.

Thirdly Lockheed did not suffer the development pain which Northrop did with their stealthy exhaust ducts. The lining of the YF-23 exhausts is a laminated alloy structure full of tiny cooling holes fed by engine bleed air. It was apparently rather heavy and may have required major design changes to bring it to production. Also the main weapon bays of the YF-23 apparently stacked the Amraams vertically and the USAF were unhappy about the potential for jams in the launcher mechanism preventing the firing of subsequent missiles.

Northrop, true to their tradition, created a showpiece of the state of the art in technology - ie a high performance truly all aspect stealth airframe with better speed/range performance and bigger weapon bays than its rival. The price of innovation was the loss of the contract, as the YF-23 combines a lot of new ideas which have never been used before. Whereas the Lockheed F-22 is clearly an evolutionary development of current aerodynamic/stealth technology, the Northrop YF-23 is very much revolutionary. Therefore risky.

Similarly, the P&W engine was conservative, whereas the GE engine was a radical variable bypass ratio design never used in production before.

4.Industrial Base
MDC and Northrop have ongoing commitments for the C-17, F/A-18 and B-2 respectively, whereas Lockheed and GD don't really have any real military projects left once the P-3 and F-16 are completely closed. Similarly GE will be building F110s and F404s for F-16 and F-18 production to the end of the decade, whereas P&W only have the F100 for which the biggest user, the USAF F-15 force, is unlikely to seek additional purchases.

Therefore, a decision to buy Northrop/GE could have seen both Lockheed and P&W end up shutting down their military airframe/engine businesses around the end of the decade.

Summary
The US taxpayer is getting the cheaper and more predictable product with some penalty in top end performance and long term performance growth potential.

The USAF however had NO choice in this matter as the Administration killed the A-12 Avenger in January due cost overruns resulting from high risk R&D. By killing off the radical but high performance A-12, the Administration set a clear precedent. The A-12 was considered a very secure project politically because its cancellation would mess up Navy deployment plans for the next decade (the A-6Es are very old, basic airframe design 1958) and cause all sorts of problems.

In comparison with the A-12, the ATF was considered politically expendable as it is seen (incorrectly in my opinion) as a dedicated killer of PVO/VVS aircraft, while the F-15s will remain viable for at least another decade.

As a result, the USAF had no choice than to pursue the lowest risk design options regardless of any other criteria. As it turns out, both Lockheed and P&W were desperate enough to submit lower bids and hence the decision could not have really gone the other way. If the USAF chose the F-23 and it got into difficulties say in 1994 due R&D problems, it would almost certainly die the death of the A-12. Politicians generally seem to have little respect for air warfare strategy.

As for the future of the F-23, it may not end up being adopted by the Navy simply because the Navy is having real money problems, ie buying F-18s instead of its preferred F-14s. Therefore the Navy is unlikely to buy any Naval ATFs until the end of the decade, by which time the Lockheed product will have matured whereas the Northrop one will have sat on the shelf.

Alternative roles for the airframe could be theatre strike and reconnaisance, but it is basically too good an airframe for these jobs and hence cheaper options could be found.

Final Observation: politics is always a stronger decision criterion than technology or air warfare strategy.