Harry Andreas wrote:

In article ,
wrote:

WaltBJ wrote:

Having used an IRSTS in the F102A for over a year and a half (and
teaching its use to other pilots) I am continually amazed at the
refusal of the USAF and USN to employ some form of IRSTS in their
fighters.

Walt, the F-14 has had an IRSTS since the earlyt '80s, and the F-14D had
both IRSTS and TCS. Modern FLIR pods can also do double duty as IRSTS,
albeit they usually will be cued by radar.

As simple and crude as the Deuce's IR system was, it still
added a whole new spectrum of attack modes to the weapons system.
Undetectable, unjammable, good against fighters in the weeds, line of
sight detection against head-on B58s at M 2.0 and picking up
afterburning 106s at 40 miles head-on. Surely a 21st century IRSTS
would be far superior to what we enjoyed back in the 60's. And the
Deuce's system weighed less than 50 pounds all told . . . the powers
that be might ask themselves why the Russians have IRSTS on all their
fighters.

Part of the reason is that they were designed to operate under tight GCI,
and their a/c radars were/are generally much inferior to US systems as
far as performance goes. So, the ability to be vectored by GCI within
range and then use a passive system for acquisition/tracking instead of
letting the opposing pilots know their general direction (by RWR) where
they're coming from,which allows the other side to radar search for them
long before they reach their own detection range, probably plays a big
part. As long as we feel we have the BVR range advantage, we don't want
to close to IR missile range. In the case of the F-22 and even more the
F-35, both of them will be getting a lot of their info from off-board
sensors, as well passive sensors (the F-35 will have two internal FLIRS,
one forward and the other downward-looking). And then there's always the
money issue, which Kevin mentioned -- with the F-22 costs spiraling out
of sight, I imagine they looked to cut the 'nice to have' stuff to try
and keep the cost reasonable [Sic.] and make sure it gets into
production, after which they can then load it up with all the goodies as
retrofits.

The IRST was deleted at program inception, long before the costs spiralled
out of control.
The reason? Cost. They knew well from experience that the cost of the
hardware, cost of the software, and cost of integration and flight test
were going to be too high to support it's functionality.
I can only imagine how bad it would be now if they had decided to keep it.
(BTW, I worked the ATF program and early parts of F-22)

One wonders then why the F-35 will have two of them, and why the F-16 Block 60s
are also getting an internal FLIR.

Guy