On January 13, 1975, Air Force Secretary John McLucas announced that the General Dynamics YF-16 had been selected as the winner of the ACF contest over the Northrop YF-17. The reasons given for this decision was the fact that the YF-16 was a little faster than the YF-17, and that its F100 engine was in use in other warplanes that were already in service. The F-16 went on to become successful beyond anyone's wildest imagination, and over 3500 have been built, with production still continuing.
It would appear, then, that the YF-17 would be consigned to oblivion, to be remembered today only as an obscure footnote in aviation history. The loss of the USAF ACF contact to the General Dynamics YF-16 might ordinarily have been the end of the line for the Northrop design, were it not for the US Navy's desire for a new fighter. All throughout the early 1970s, some US Navy officers had been expressing interest in a low-cost alternative to the Grumman F-14 Tomcat, which was at that time experiencing severe teething troubles and suffering from a series of cost overruns. This program came to be known as VFAX.
The VFAX was envisaged as a multi-role aircraft which would replace the F-4 Phantom, the A-4 Skyhawk, and the A-7 Corsair II in Navy and Marine Corps service. To meet the VFAX requirement, a stripped version of the Tomcat (named F-14X) had been proposed by Grumman, but had been summarily rejected by the Deputy Defense Secretary. In May 10, 1974 the House Armed Services Committee announced that it was not going to have anything to do with a stripped-down Tomcat either, and dictated that the VFAX would have to be a wholly new aircraft. Apparently having forgotten the sorry experience with the F-111, the Committee wanted the USAF and the Navy to purchase basically the same plane. However, the Navy (unlike the Air Force) wanted the VFAX to be capable of filling both air-to-air and ground-attack roles. However, in August of 1974, Congress decided that the budget simply could not afford another major aircraft development project at that time and informed the Navy that the VFAX project would have to be canceled.
However, Congress took money intended for VFAX and diverted it to a new program known as Navy Air Combat Fighter (NACF), and directed that the Navy take a close look at the USAF's LWF/ACF contenders as possible candidates for the NACF requirement. The Navy's NACF would be basically a navalized LWF/ACF that had led to the F-16. However, most Navy officers were still solidly committed to the F-14 and wanted nothing to do with either the VFAX or the NACF. Undeterred by the pro-Tomcat faction, in September of 1974 the Navy pressed forward with the NACF project and formal requirements were issued.
Once the formal requirements had been issued, the Navy announced that it would select a single contractor to begin engineering development of the NACF. Northrop thought that they had a potential candidate for the NACF in the YF-17, since the Navy tended to prefer the added safety presumably offered by a twin-engine format and the design seemed to have greater potential for growth into a radar-equipped multirole aircraft. However, the Northrop company had no experience with carrier-based aircraft, so they accepted an offer from McDonnell Douglas to collaborate on a naval adaptation of the YF-17 for the NACF contest. Under the terms of the agreement worked out between the two corporations, McDonnell would market the aircraft to the Navy, and Northrop would be the prime subcontractor. In addition, Northrop was to be given the rights to market a land-based version of the design to various foreign air forces.
General Dynamics also wanted to get into the game with an offer based on a navalized F-16. Since General Dynamics did not have any experience with carrier-based aircraft either, they announced that they would be teaming up with Ling-Temco-Vought (also located in Dallas/Fort Worth) to propose a NACF based on the YF-16. The navalized YF-16 was to have BVR radar, which was not part of the original planning for a USAF F-16. If both the Air Force and the Navy picked the YF-16, General Dynamics would be the prime contractor for the Air Force and LTV would be prime contractor for the Navy. However, since both of these contractors were located in the same state, there was probably little likelihood of receiving a contract.
On May 2, 1975, the Navy announced that they had opted for the Northrop/McDonnell Douglas proposal. The Navy liked the twin-engined format of the Northrop/McDonnell Douglas submission, which they felt would be better suited to operations at sea. In addition, the Navy felt that the YF-17 development possessed greater potentiality for multi-mission capability.
According to the original plan, the Northrop/McDonnell Douglas aircraft was intended to be procured in three closely related models--the single-seat F-18 which would replace the F-4 Phantom in the fighter role, the single-seat A-18 which would replace the A-7 Corsair II in the attack role, and the two seat TF-18A combat trainer. The F-18 and the A-18 were to share the same basic airframe and engine arrangement, but were to differ in stores attachments and in the avionics. The two-seat TF-18A was to retain the full mission capability and armament suite of the F-18A, but was to have slightly reduced fuel capacity.
Eventually, however, careful redesign made it possible to merge the two single-seat fighter and attack versions into a single aircraft, which was initially referred to as F/A-18A in Defense Department press releases. This rather awkward designation did not actually become official until 1984. This commonality was made possible primarily by careful redesign of the two stores pylons (stations 4 and 6) located on the lower corners of the air intakes. In the fighter role, these pylons would carry AIM-7 Sparrow air-to-air missiles, and when operating in the attack role they would carry a forward-looking infrared scanner on the left hand side and a laser spot tracker on the right hand side. The combat capable two-seat trainer was successively redesignated TF/A-18A and then F/A-18B.
Although no orders had yet been received, a land-based version known as the F-18L was also planned. Because it did not have to be carrier-capable, the F-18L was expected to be significantly lighter and better-performing than the carrier-based version.
The F-18 program went ahead with the award of letter contracts in November of 1975 to General Electric for the development of the F404 turbofans and on January 22, 1976 to McDonnell for nine single-seat and two two-seat Full-Scale Development (FSD) aircraft. First flight was to take place in July of 1978. As part of the agreement between McDonnell Douglas and Northrop, it was decided that fabrication of the baseline F-18 would be split roughly 60/40 between McDD and Northrop, respectively. If orders were received for the F-18L land-based version, these proportions would be reversed. Northrop was to build the center and aft fuselage sections of the F-18 as well as both vertical fins. McDD's contribution would consist of the wings, the horizontal tail, and the forward fuselage, including the cockpit. The major subassemblies were to be shipped to McDonnell at St Louis where final assembly would take place.
In anticipation of the appearance of the F-18, the second YF-17 was turned over the Navy for test duties with the Pacific Missile Test Center at Point Mugu, California, the Naval Air Test Center at Patuxent River, Maryland, and the Naval Weapons Center at China Lake, California.