XB-70 vs B-2

The MiG-25 was designed specifically to counter the B-70.

Correct. Wasn't the B-70 killer missile the Mig-25 was designed to
carry called the "Anab"? 40 feet long IIRC. Huge mutha.


No... the MiG-25 had the R-40 missile (NATO name AA-6 "Acrid"). And
it was only about 20 feet long.

FAS has a couple pictures... I wouldn't take their range and
performance data seriously (on anything), but as far as physical
dimensions they seem to be in the ballpark.

http://www.fas.org/man/dod-101/sys/missile/row/aa-6.htm

"Bob Martin" wrote in message
om...
The MiG-25 was designed specifically to counter the B-70.

Correct. Wasn't the B-70 killer missile the Mig-25 was designed
to
carry called the "Anab"? 40 feet long IIRC. Huge mutha.


No... the MiG-25 had the R-40 missile (NATO name AA-6 "Acrid"). And
it was only about 20 feet long.

FAS has a couple pictures... I wouldn't take their range and
performance data seriously (on anything), but as far as physical
dimensions they seem to be in the ballpark.

http://www.fas.org/man/dod-101/sys/missile/row/aa-6.htm

Thanx for the correction, Bob. It's been too long since this old fart
looked up that data. ;-)

But since the Mig-25 was designed to attack at high speeds (and at
high speeds everything, attacker and attackee, travels in a straight
line), the Mig-25 had small tailfeathers and hence low manuevrebility
(sp?). So, it's intended target gone, the 25 became a photorecon
platform. It and the later Mig-31 Foxhound in effect became the
Soviet's SR-71.

Was the AA-6 Acrid missile dropped, or was it "retargeted"?

On Fri, 19 Dec 2003 05:07:37 GMT, Chad Irby wrote:

In article ,
(WaltBJ) wrote:

The B70 was doomed once its IR signature was analyzed. Even the B58 at
M2.0 had an IR signature the 102's poor old LN2 cooled seeker head
could detect about 100 miles away. And we found the IR Falcons could
track the B58, too. At least the IR WESM (Weapons System Evaluator
Missile) brought back tapes showing the missile seeker head was locked
on and tracking - during a frontal attack. Now, A B70 at M3.0 and
+75000 would be like a giant IR beacon with a radar signature like the
Vertical Assembly Building, all screaming 'Shoot Me'.

The only problem with high-speed IR missiles over long ranges is that
the window in the front of the seeker head gets hot enough to blind the
warhead.

The AIM-47 Falcon had something like a hundred mile range and flew at
Mach 6. It had IR terminal guidance. Today's THAAD uses IR also
(several others do but they use kill vehicles that are protected
before the leave the atmosphere). HEDI also used an IR terminal
guidance. Think of HEDI as a hit-to-kill Sprint missile. I don't
know if they ever did get the IR seeker to work though. ISTR it was
cooled by nitrogen gas flowing over the outside of the seeker and used
a synthetic sapphire window.

(Bob Martin) wrote in
om:

The MiG-25 was designed specifically to counter the B-70.

Correct. Wasn't the B-70 killer missile the Mig-25 was
designed to carry called the "Anab"? 40 feet long IIRC. Huge
mutha.


No... the MiG-25 had the R-40 missile (NATO name AA-6 "Acrid").
And it was only about 20 feet long.

FAS has a couple pictures... I wouldn't take their range and
performance data seriously (on anything), but as far as physical
dimensions they seem to be in the ballpark.

http://www.fas.org/man/dod-101/sys/missile/row/aa-6.htm

Interesting to note that the images depict the IR version,
except the mid bottom image, which shows the usual mix
of IR on the two inner pylons and radar seekers on the
two outboard pylons.


Regards...

On Sat, 20 Dec 2003 19:17:34 GMT, "Felger Carbon"
wrote:

"Bob Martin" wrote in message
. com...
The MiG-25 was designed specifically to counter the B-70.

Correct. Wasn't the B-70 killer missile the Mig-25 was designed
to
carry called the "Anab"? 40 feet long IIRC. Huge mutha.


No... the MiG-25 had the R-40 missile (NATO name AA-6 "Acrid"). And
it was only about 20 feet long.

FAS has a couple pictures... I wouldn't take their range and
performance data seriously (on anything), but as far as physical
dimensions they seem to be in the ballpark.

http://www.fas.org/man/dod-101/sys/missile/row/aa-6.htm

Thanx for the correction, Bob. It's been too long since this old fart
looked up that data. ;-)

But since the Mig-25 was designed to attack at high speeds (and at
high speeds everything, attacker and attackee, travels in a straight
line), the Mig-25 had small tailfeathers and hence low manuevrebility
(sp?). So, it's intended target gone, the 25 became a photorecon
platform. It and the later Mig-31 Foxhound in effect became the
Soviet's SR-71.

Was the AA-6 Acrid missile dropped, or was it "retargeted"?



They use the AA-9 (Phoenix ripoff) as the main armament on the Mig-31
although the AA-6 is also shown in some pictures.

Scott Ferrin wrote:

You could make a case for a Sam being able to knock out any airplane. So why
build any at all?

Assuming B70's were built and upgraded umpteen times by now,
what do you think the results would be with a re-engine of the six pack with a
modern supercruise engine such as a F119?

Bob

Actually I'd be surprised if the F119 powered one wasn't *slower*.
The J93 was designed for Mach 3 and high altitudes. The F119 is not.

I realize that airflow and inlet geometry are critical for a high
mach plane, but what would be different in the guts of the engine?
Did the XB-70 burn a non standard fuel like the SR71?

I suppose my point was expanded range or payload using the
F119. Who knows, maybe there is a orphan XB70 made out
of spare parts laying around groom lake somewhere.
Might be an interesting platform to test some of the new high
tech aero spike or pulse engines.

Bob



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In article ,
Scott Ferrin wrote:

On Fri, 19 Dec 2003 05:07:37 GMT, Chad Irby wrote:

In article ,
(WaltBJ) wrote:

The B70 was doomed once its IR signature was analyzed. Even the B58 at
M2.0 had an IR signature the 102's poor old LN2 cooled seeker head
could detect about 100 miles away. And we found the IR Falcons could
track the B58, too. At least the IR WESM (Weapons System Evaluator
Missile) brought back tapes showing the missile seeker head was locked
on and tracking - during a frontal attack. Now, A B70 at M3.0 and
+75000 would be like a giant IR beacon with a radar signature like the
Vertical Assembly Building, all screaming 'Shoot Me'.

The only problem with high-speed IR missiles over long ranges is that
the window in the front of the seeker head gets hot enough to blind the
warhead.

The AIM-47 Falcon had something like a hundred mile range and flew at
Mach 6. It had IR terminal guidance. Today's THAAD uses IR also
(several others do but they use kill vehicles that are protected
before the leave the atmosphere). HEDI also used an IR terminal
guidance. Think of HEDI as a hit-to-kill Sprint missile. I don't
know if they ever did get the IR seeker to work though. ISTR it was
cooled by nitrogen gas flowing over the outside of the seeker and used
a synthetic sapphire window.

Yeah, you have to do some serious redesign to make IR a good high-speed
targeting method. It's just easier to do it the other way around for
the sort of target we're looking at - superfast, very high.

The AIM-47 never really worked that well, though they used some of the
lessons learned to make the AIM-54 Phoenix... without the IR.

--
cirby at cfl.rr.com

Remember: Objects in rearview mirror may be hallucinations.
Slam on brakes accordingly.

On Sat, 20 Dec 2003 21:23:42 GMT, Chad Irby wrote:

In article ,
Scott Ferrin wrote:

On Fri, 19 Dec 2003 05:07:37 GMT, Chad Irby wrote:

In article ,
(WaltBJ) wrote:

The B70 was doomed once its IR signature was analyzed. Even the B58 at
M2.0 had an IR signature the 102's poor old LN2 cooled seeker head
could detect about 100 miles away. And we found the IR Falcons could
track the B58, too. At least the IR WESM (Weapons System Evaluator
Missile) brought back tapes showing the missile seeker head was locked
on and tracking - during a frontal attack. Now, A B70 at M3.0 and
+75000 would be like a giant IR beacon with a radar signature like the
Vertical Assembly Building, all screaming 'Shoot Me'.

The only problem with high-speed IR missiles over long ranges is that
the window in the front of the seeker head gets hot enough to blind the
warhead.

The AIM-47 Falcon had something like a hundred mile range and flew at
Mach 6. It had IR terminal guidance. Today's THAAD uses IR also
(several others do but they use kill vehicles that are protected
before the leave the atmosphere). HEDI also used an IR terminal
guidance. Think of HEDI as a hit-to-kill Sprint missile. I don't
know if they ever did get the IR seeker to work though. ISTR it was
cooled by nitrogen gas flowing over the outside of the seeker and used
a synthetic sapphire window.

Yeah, you have to do some serious redesign to make IR a good high-speed
targeting method. It's just easier to do it the other way around for
the sort of target we're looking at - superfast, very high.

The AIM-47 never really worked that well,


You might want to read up on the test shots. Even today they are some
of the most impressive out there and they were like six for seven on
hits and some of them were direct hits. Not to mention all of them
were shooting down :-) with one of them smacking a target at 1500
feet from something lik 75 to 80,000 ft.

On Sat, 20 Dec 2003 15:19:54 -0600, BOB URZ
wrote:



Scott Ferrin wrote:

You could make a case for a Sam being able to knock out any airplane. So why
build any at all?

Assuming B70's were built and upgraded umpteen times by now,
what do you think the results would be with a re-engine of the six pack with a
modern supercruise engine such as a F119?

Bob

Actually I'd be surprised if the F119 powered one wasn't *slower*.
The J93 was designed for Mach 3 and high altitudes. The F119 is not.

I realize that airflow and inlet geometry are critical for a high
mach plane, but what would be different in the guts of the engine?
Did the XB-70 burn a non standard fuel like the SR71?

It didn't use special fuel (although they wanted to use a fuel with
boron added at one point). I *think* part of the reason for the
differences would be related to the compression ratio of the engines
and that they were straight turbojets rather than turbofans. The
XB-70, Blackbirds, and Mig-25 all used low pressure engines I *think*
because at high speed they compressed the air so much to get something
to work with that by the time it got to the engines they couldn't take
the temperature of compressing a ton more. ISTR the J93's compression
ratio being around 9 to 1 whereas something like the F100-129 is up
around 32-1 or 36-1. Then again they though the could get the
Crusader III up to 2.9 with a J75 so who knows. All of this is just
my opinion from what I've read over the years so hopefully someone
will weigh in who knows a lot about it.

"BOB URZ" wrote in message
...


Scott Ferrin wrote:

Assuming B70's were built and upgraded umpteen times by now,
what do you think the results would be with a re-engine of the
six pack with a
modern supercruise engine such as a F119?

Bob

Actually I'd be surprised if the F119 powered one wasn't *slower*.
The J93 was designed for Mach 3 and high altitudes. The F119 is
not.

I realize that airflow and inlet geometry are critical for a high
mach plane, but what would be different in the guts of the engine?
Did the XB-70 burn a non standard fuel like the SR71?

Hey, it's Xmas. Mebbe I can make another mistake.

For a supersonic aircraft, the purpose of the inlet geometry is to
reduce the supersonic airflow at atmospheric pressure to subsonic
airflow at super-atmospheric pressure. ;-)

This means there's more oxygen to burn more fuel, thus getting more
power. It also runs the engine hotter. The faster the supersonic
aircraft goes, the hotter the engine can run.

This raises the following critical question: how long an engine life
do you want? I understand the Mig-31 Foxhound is _capable_ of
astonishingly high speeds, as it has demonstrated on at least one
occasion in the mideast. It generally doesn't, because an immediate
engine overhaul/replacement is then needed.

The F-119 engined F-22 has fixed inlets and is not especially fast.
The engine, therefore, does _not_ have to be made of the *very*
expensive highest-temperature alloys. My question is, how long would
the F-119 last in a mach3 aircraft like the B-70?