Sujay,

originally, the AWG-9&AIM-54 combo was developed from the AN/ASG-18&AIM-47
combo, which was the first high-performance, long-range, LDSD PD radar ever.
The AIM-47, although developed from the (pretty nifty) Falcon family of USAF
AAMs, was probably the best and most effective up to its time.

Anyway, the AN/ASG-18 and AIM-47 were installed on three Lockheed YF-12A
interceptors, armed A-12 OXCART derivatives, preceeding the SR-71, which the
USAF evaluated in the mid 60's. The whole system proved very successful in
tests, and was even able to track ICBMs fired from Vandenberg AFB, even if
no actual shoot-downs were attempted. The system was backed up by two IRST
sensors, but these were dropped during the course of system testing. The
AN/ASG-18 was just as range-capable as the AWG-9, but, AFAIK could only deal
with a single target at a time. The AIM-47 actually out-ranged the AIM-54
due to its better kinematic performance - as much as the fact that the
YF-12s were usually underway at a speed of Mach 3.2 when launching (so that
the AIM-47 was tracked at speeds well over Mach 4.4).

The AIM-47 also utilized dual-mode SARH/IR terminal homing, and it has been
speculated that a 200kT nuclear warhead would have been fitted to production
weapons at some point in the development process. This ultimately turned out
to be both false and unnecessary, as on one occasion an AIM-47 trials round
skewered the vertical tail of a QB-47 target drone. With such accuracy
nobody needed nukes.

The proposed production F-12B interceptor was cancelled, and the YF-12s went
to NASA for high-speed research before Lockheed could begin evaluating the
AN/ASG-18 system in more intensive environments, such as heavy ECM.

Shortly after the USAF dropped the AN/ASG-18 and AIM-47 both were taken over
by the USN and then the development of the AWG-9 and AIM-54 was initiated.


Why were the AWG-9 and the AIM-54 not put into any other plane?

The answer is simple: needs at the time and the aircraft construction.

The AWG-9 was a huge system when designed for the F-111B, which was
developed for service aboard the USN carriers through the 1960s. Although
considerably updated and thus made lighter by almost 500kg, it remained a
huge system when it was put into the F-14, in 1969. And still, the F-14 was
not designed "around" the AWG-9 and the AIM-54, but first as a dogfighter,
armed with a gun, Sparrows and Sidewinders, to fight MiG-17s and MiG-21s.
Once this capability was developed, the designers went to find out how to
fit the AWG-9 and the AIM-54s on it. One of the results of this work became
the "paletts" on which the AIM-54s are mounted. Another was the largest
cockpit of any fighter aircraft ever.

Doing anything similar with any other type would not function for several
reasons. When designing the F-15, the USAF actually wanted to have an
aircraft like the F/A-18 later became, a dogfighter and a one-seater. Only
the shock from the appearance of the MiG-25 caused them to let the F-15
become as large as fast as it become, in order to be able to intercept
Foxbats. Clearly, the F-14 with its "long claws" would have been even better
for this task, but there was no way the USAF would buy a USN fighter (again,
like it did in the case of the F-4).

The F-16, on the contrary, was designed as a simple dogfighter, day-fighter
armed with the gun and Sidewinders only. Only after it entered service was
any separation testing for the use of Mk.82783/84 bombs done. All the
complex avionics was added to it even at a later stage.

Finally, the F/A-18 came into being as the YF-17, the competitor for the
same project like the F-16, which was then redesigned so to become suitable
to replace the A-7, but also support the F-14 in air-to-air. Consequently,
it was to be cheap and simple, not as complex as the F-14.

Tom Cooper
Co-Author:
Iran-Iraq War in the Air, 1980-1988:
http://www.acig.org/pg1/content.php
and,
Iranian F-4 Phantom II Units in Combat:
http://www.osprey-publishing.co.uk/t...hp/title=S6585