F-108 Rapier Question

[Weaver]

Weaver

At the time it was widely assumed that the next generation of bombers would be supersonic, with mach 2 ones following not long afterwards.

Still, a Mach 2 bomber would probably only require an interceptor with a top speed of Mach 2.5 to 3.0 to intercept it: The F-106A fit this profile pretty good actually

Missing the point: it's not just about how long it takes the interceptor to chase the bomber down, it's also about how far the bomber moves between first being detected (no AWACS, remember) and being intercepted. The interceptor has to get out to the bomber's position (and altitude) as fast as possible, then it has to make a HUGE radius turn because it doesn't want to slow down, and then it has to tail-chase the bomber. Obviously launching a missile head-on whilst on the way out is a an advantage, but with 1950s tech, Genie was the only way to make this lethal enough.

In order to avoid a pyrrhic victory, you had to down almost all of them before they got within range of their targets, and the introduction of stand-off missile technologies was pushing that "in range" figure up into the hundreds of miles.

Well, the F4D-1's APQ-50 had a maximum effective range of 200 miles, I assume the F-102A was similar or a little bit greater: Maximum effective and practical weren't the same though and the actual range you'd pick up a bomber-sized target, track it reliably; then get a missile lock were closer in. 

I'm not sure how much technology limited lock-on ranges, but the missiles were a limiting factor.

The radar lock-on range is irrelevent if all you can do is use it to watch the bomber's stand-off missile being launched. As you say, AAM technology was the limiting factor.

So the challenge was to race out to the furthest possible interception line, engaging some bombers head-on (hence the Genie et all: only way to get the lethal radius bigger than the miss-distance with 1950s tech)

Well, the Genie was proposed for several purposes

1. Wasting multiple bombers at once: There might have been some people who felt that the USSR would use formations that would be similar to the RAF or USAAF's.  While the RAF's formations were somewhat looser than the USAAF's, they were pretty close from the standpoint of a nuclear blast!

As far as I know, this is a complete (but admittedly oft-quoted) myth. There is NO reason to suppose that attacking nuclear bombers would be flying in any kind of formation, or even close enough that more a couple might be affected by a Genie at most.

2. If you can't hit accurately enough: Make a big enough bang:  The early missiles had reliability issues and should they fail this would ensure a kill even guidance systems

This is the main reason for Genie. Even when AAMs "worked" head-on, they still had average miss distances so great that a conventional warhead big enough to ensure a kill would be getting prohibitively heavy. This is one of the reasons why the British Red Dean/Red Hebe active radar homer ended up the size and weight of an Exocet before it was cancelled.

That was hard enough with Mach 0.9 bombers, which required Mach 2 fighters to get out to the interception line between "first warning" and "too late" and then overhaul the bombers in a tail chase. Now multiply the speed of the bombers by two....

Actually the F4D was quite effective at intercepting subsonic bombers and it only could do Mach 1.5 if I recall right.

F-4s are generally listed as having a Mach 2.2ish top speed. I didn't say it wasn't effective at intercepting Mach 0.9 bombers, my point was that if it takes a (roughly) Mach 2 fighter to intercept a Mach 0.9 bomber, then it takes a Mach 4 fighter to intercept a Mach 2 bomber.

The maximum speed you can go to before an aluminium airframe starts melting is about Mach 2.8, so making anything faster involves using stainless steel (horrible to form) or titanium (hideously expensive and mostly from Russia), and that proved impractical for more than a handful of spy planes, let alone a fleet of hundreds of interceptors. The better solution was to improve the missiles to make the head-on shots work at longer range, but then the threat to strategic land targets changed to ICBMs. It persisted for naval targets, hence the F-14/AIM-54 combo.

the F-102A was capable of probably at least Mach 2 based on the following

• The YF-102 was capable of doing Mach 0.98 max in level flight
  
• The YF-102 could do 812 to 870 mph in a dive or mach 1.23 to 1.32
  
• I do remember (in a rather old book) about the Air Force (1968-1972 about) stating the F-102A was more than twice as fast as the YF-102A: This equates to 1.96 or greater based on level flight speed (most likely), or 2.46 to 2.64 if the speed was more than twice as fast in level flight as the dive speed (less likely based on the fact that the F4D's often seemed to be used for NORAD use and did okay)
  
• While this source is old, the fact is that in those days they would be more likely to under-rate the performance of the planes than modern day; not overrate.
  

Think you're getting confused here: the F-102 did Mach 1.25 max.

The F-106A was considerably faster owing to a more cleaned up fuselage, and variable geometry inlets.  Even those on the F-106 Delta Dart site admitted openly to a top speed of at least Mach 2.5, and made a comment about the vertical tape maxing out at either 2.80 to 2.85

Which is the thermal limit I mentioned earlier.

Ultimately, the difficulties of this air defence situation are why the UK gave up comprehensive air defence and concentrated on defending the V-bomber bases for just long enough to get them on their way: there was no point bankrupting the country to provide an 80% effective defence when the two dozen or so nukes that got through would wipe us off the map anyway.

That's why you guys just stuck with the Lightning?

Partly, although there was also the 1957 White Paper which declared that manned aircraft were obsolete and everything would be done with missiles in the future. The Lightning was only grudgingly allowed to proceed because it was deemed too far advanced to cancel.

Britain had a whole series of air defence plans thoughout the 1950s, but as the magnitude of the technical challenge became apparent and the nature of the projected threat evolved, the gulf between what was needed and what could be afforded expanded exponentially. In the end, deterrence became the cheaper option, and all that was needed then was to keep that deterrence credible by defending the V-bomber bases long enough for them to take off.

[jcf]

The 'infamous' White Paper, which doesn't quite say what many claim:
http://filestore.nationalarchives.gov.uk/pdfs/small/cab-129-86-c-57-84-34.pdf

Robyn, your attempt at quantifying the Lightning is ludicrous, the original
intent for development of the Lightning and the realities of the geo-political
environment in which it came to operate, many years later, are two different
things.

BTW the way in Jenkins and Landis Valkyrie, max operating speed for
all J93 dashes is listed as Mach 3.2. The only mention of Mach 4 is claims
from Wright that their engine was capable of pushing 'a highly developed and
extensively modified XB-70 based aircraft to Mach 4'. Nothing about the
XB-70 itself being capable of Mach 4, which it wasn't, as the difficulties getting
it to and above Mach 3 amply demonstrate.

[KJ_Lesnick]

Weaver

Missing the point: it's not just about how long it takes the interceptor to chase the bomber down, it's also about how far the bomber moves between first being detected (no AWACS, remember) and being intercepted.

I thought there was a Connie variant as an AEW bird?

As far as I know, this is a complete (but admittedly oft-quoted) myth. There is NO reason to suppose that attacking nuclear bombers would be flying in any kind of formation, or even close enough that more a couple might be affected by a Genie at most.

So it was simply to create a big enough bang?

Even when AAMs "worked" head-on, they still had average miss distances so great that a conventional warhead big enough to ensure a kill would be getting prohibitively heavy.

Even with a proximity fuse?

F-4s are generally listed as having a Mach 2.2ish top speed.

We're having a communications gulf... the F4D-1 Skyray is not the same as the F-4D Phantom II... the F4D-1 Skyray was able to do around 1.5 mach (Admittedly I'm not sure about it's top-speed, but it could do 1.05 down-low clean all out).  Theoretically if you could knock a bomber doing mach 0.9 dead with a 1.5 mach interceptor you would not need a Mach 4 fighter to do the job.

Furthermore, the F-108 might have been set-up to nail a Mach 3 bomber, at least the earlier XF-103 was built around this goal and Mach 4 performance would be a good start especially with a long-range radar and missiles that would not be so bad.

The maximum speed you can go to before an aluminium airframe starts melting is about Mach 2.8, so making anything faster involves using stainless steel (horrible to form) or titanium (hideously expensive and mostly from Russia), and that proved impractical for more than a handful of spy planes, let alone a fleet of hundreds of interceptors.

The F-106's leading edges were made out of steel actually, further back you had honeycomb aluminum, then regular aluminum; near the tail you had titanium.  

More aircraft than you think had titanium in them to some degree including the F-100, F8U/F-8, F-106, and probably the F-4

The better solution was to improve the missiles to make the head-on shots work at longer range

The GAR-9/AIM-47...

but then the threat to strategic land targets changed to ICBMs.

With the exception of Nap o' the Earth

It persisted for naval targets, hence the F-14/AIM-54 combo.

Why did it persist for USN targets?  Was it the fact that the mobility of the carriers made them unfeasible to hit with a ballistic missile at the time?

Partly, although there was also the 1957 White Paper which declared that manned aircraft were obsolete and everything would be done with missiles in the future.

Not so smart...


JCF[/b]

Robyn, your attempt at quantifying the Lightning is ludicrous, the original
intent for development of the Lightning and the realities of the geo-political
environment in which it came to operate, many years later, are two different
things.

I just wanted to clarify what Rickshaw was saying...

BTW the way in Jenkins and Landis Valkyrie, max operating speed for all J93 dashes is listed as Mach 3.2.

Yes, but Walt Spivak was allegedly quoted in saying the plane was good to Mach 4, he was the Chief Engineer so his statement carries some weight.

[rickshaw]

rickshaw

Or need anything else.  The Lightning provided sufficient of a fig leaf so that HMG could demonstrate to foreign and domestic observers that they were serious about defending UK airspace.  Without that, they believed they would lose the confidence of the electorate and their allies.

So the Lightning was 20% aimed at defending the UK Airspace, and 80% at showing the UK public that there's something there to defend them; allies that you guys could protect yourself; and of course telling the Russians that you couldn't be easily jumped?

I wouldn't attempt to quantify it, Kendra/Robyne.   The reality was that as they developed the Lightning, the manned bomber threat had been replaced by the ICBM.  The Lightning's value was in showing to foreign and domestic observers that the UK was at least willing to put up at least a token, conventional resistance to foreign incursions into UK airspace.   That they weren't willing to fund a replacement for the Lightning until the 1980s, long after it's utility had decreased due to age (and a yet again changing threat), rather indicates they couldn't justify a new interceptor.   Instead they misused the Phantom and the result was a severe curtailing of it's life.

[Iranian F-14A]

but then the threat to strategic land targets changed to ICBMs.

With the exception of Nap o' the Earth

This is only if you trying to shoot down USAF/NATO (and of course French) bombers. The Soviets(and later Russians) never vested much in low level bombing with the exception of the Su-24 Fencer, and even then, it was on a tactical, possibly theatre level at most. The Tu-16 Badger, Tu-22 Blinder, Tu-95 Bear and Tu-160 Blackjack are all optomized for high altitude nuclear strike. Even the Tu-22M Backfire when it was used in the conventional role over Afghanistan was used from high altitudes. The Russians never chainged their tactics, mainly because the US, unlike the USSR did not vest too much in SAM defenses for cities. They did have the Nikes, sure, but those have been gone for ages. Interceptors have been an issue, but even today, more ANG units are trading in their F-16s for C-130s, so again ,the threat of interception goes down. SAC bombers had to face numerous SAMs AND interceptors, so it made sense in the case of the B-52 and B-1 to change their flight profiles to low altitude to avoid all that.

[tahsin]

So the Lightning was 20% aimed at defending the UK Airspace ...

The Lightning was 100% consolidating the rather fragmented UK industry by closing the design offices down left without trade. Although the lack of progress with the "Last fighter ever" and the increasing capabilities of missiles forced a purchase of the Phantoms which kept Hawker Siddeley in business long enough to get the Harrier in. If only because in defence business if you get a contract, the competition expects the next one.

As for Russian airborne deterrent, America always had more defences in any comparable timeframe, with the exception of the ABM battery around Moscow. The lack of dedicated interceptors or SAM belts must be evaluated with the available number of Russian bombers.

maximum effective range of 200 miles

Ah, I think that's "somewhat" off. F-16/18 radars can be compared perhaps; do they so anything like that 50-60 years on?

[Weaver]

Even when AAMs "worked" head-on, they still had average miss distances so great that a conventional warhead big enough to ensure a kill would be getting prohibitively heavy.

Even with a proximity fuse?

Absolutely even with a proximity fuse. The chance of a direct hit head-on was near to nil. Remember that the technical difficulties that bedevilled the homing systems also affected the fuses. In a head-on engagment between a mach 2 missile and a mach 0.9 bomber, the difference between a warhead going off too soon and going off too late is a a split second.

F-4s are generally listed as having a Mach 2.2ish top speed.

We're having a communications gulf... the F4D-1 Skyray is not the same as the F-4D Phantom II... the F4D-1 Skyray was able to do around 1.5 mach (Admittedly I'm not sure about it's top-speed, but it could do 1.05 down-low clean all out).  Theoretically if you could knock a bomber doing mach 0.9 dead with a 1.5 mach interceptor you would not need a Mach 4 fighter to do the job.

Indeed: might be an idea to call the F-4D the "Skyray" in future when you're talking about it since most people think of the Phantom when they see "F-4"....

Regarding speeds, you're missing the point again. Yes, a mach 1.5 to mach 2 interceptor can down a mach 0.9 bomber reasonably reliably, but at the time the next generation of interceptors were being planned in the late 1950s, the expectation was that the next generation of bombers would be doing mach 2+, therefore for the interceptors to maintain any kind of speed advantage, they would need to be doing mach 2.8 or higher, with more effective missiles to boot.

It's also a bit misleading to compare the performance of a naval fighter like the Skyray with that of a continental interceptor like, for instance, the F-106. The naval air defence situation is geometrically very different, because even a relatively large task force is still, on a geographic scale, a "point" target: the interceptors know exactly where the bombers are going because there's only one place for them to go, so the attack becomes more concentrated as it approaches the target and the fighters basically just have to wait for them. When defending a continent however, there are multitude of possible targets spread over thousands of miles, so if an attacking bomber switches targets and "dog-legs", it can force the interceptor to fly "cross range" for hundreds of miles just to get back into an intercept position. Thus the land interceptor needs more performance to cover it's "territory" than the naval one.

The maximum speed you can go to before an aluminium airframe starts melting is about Mach 2.8, so making anything faster involves using stainless steel (horrible to form) or titanium (hideously expensive and mostly from Russia), and that proved impractical for more than a handful of spy planes, let alone a fleet of hundreds of interceptors.

The F-106's leading edges were made out of steel actually, further back you had honeycomb aluminum, then regular aluminum; near the tail you had titanium.  

More aircraft than you think had titanium in them to some degree including the F-100, F8U/F-8, F-106, and probably the F-4

yes, I know, but those are small bits of the airframe, subject to local heating for a short time. If you want to sustain high speeds, you get into the problem of "heat soak" where heat conducts from the place where it's being produced and raises the temperature of the whole airframe. This is why SR-71s were made entirely from titanium and MIG-25s from stainless steel.  

It persisted for naval targets, hence the F-14/AIM-54 combo.

Why did it persist for USN targets?  Was it the fact that the mobility of the carriers made them unfeasible to hit with a ballistic missile at the time?

Well the Soviets continued to deploy bombers with stand-off missiles in the anti-carrier role so the USN had to defend against them. It's also the fact that an aircraft carrier is the single highest-value target that can be detroyed by one strike with conventional weapons in a non-nuclear war, so it's worth spending hideous amounts of money defending it. Sticking three of four AS-4s into New york would be horrible, but it wouldn't destroy New York. By contrast, sticking them into the USS Nimitz, and sinking it, would be a national disaster.


Regarding the Lightning, there was also the realisation that non-nuclear, sub-strategic conflicts like Korea and Vietnam were going to keep happening and needed to be planned and equipped for, and the Lightning could be useful in those scenarios. Then NATO went over to it's Flexible Response strategy which envisaged a prolonged conventional conflict with the Soviets that may or (hopefully) may not end in nuclear war, and again, the Lightning could play a useful role in the defence of Germany. So although the logic of the nuclear war "partial defence is no defence" argument continued to apply, the range of potential war sutuations expanded beyond that of all-out nuclear war.

[KJ_Lesnick]

Rickshaw

The reality was that as they developed the Lightning, the manned bomber threat had been replaced by the ICBM.

So it was bad timing?

The Lightning's value was in showing to foreign and domestic observers that the UK was at least willing to put up at least a token, conventional resistance to foreign incursions into UK airspace.

The end result you mean?

That they weren't willing to fund a replacement for the Lightning until the 1980s

The Tornado?

Instead they misused the Phantom and the result was a severe curtailing of it's life.

How did the RAF misuse the Phantom?  I'm not really familiar with much about the RAF past WW2


Iranian F-14A

This is only if you trying to shoot down USAF/NATO (and of course French) bombers.

I thought the Russians were doing that with their Tu-22, Tu-22M, and Tu-160...

Even the Tu-22M Backfire when it was used in the conventional role over Afghanistan was used from high altitudes.

I find that very surprising

The Russians never chainged their tactics, mainly because the US, unlike the USSR did not vest too much in SAM defenses for cities.

That's a good point, why didn't we?

SAC bombers had to face numerous SAMs AND interceptors, so it made sense in the case of the B-52 and B-1 to change their flight profiles to low altitude to avoid all that.

The B-52 was designed to fly up high and was later modified to fly down-low to get through aerial defenses; the B-1 far as I know was designed to fly supersonic and high altitude over the pole, then drop to NoE and just race along down in the weeds the rest of the way


Weaver

Before we start, I did some checking and it turns out the USSR was flying a supersonic bomber back in '55 to '56.  It was the Tu-98.  I don't know how fast we thought it was to fly at but it's possible we'd have thought Mach 2 could be done at the time.

Absolutely even with a proximity fuse. The chance of a direct hit head-on was near to nil. Remember that the technical difficulties that bedevilled the homing systems also affected the fuses.

Because they work on the same principles, I get it...

We did however use intercepts that would involve a head on approach followed by an abeam approach correct?  That would lower closure rates down right?

Indeed: might be an idea to call the F-4D the "Skyray" in future when you're talking about it since most people think of the Phantom when they see "F-4"....

Good point, but one could also say F-6A... prior to 1962 it was called the F4D-1, post 1962, it was called the F-6A; prior to 1962 there was the XF4H-1, the F4H-1F, and the F4H-1 which were known later as the XF-4A, the F-4A (no idea why no YF-4A), and the F-4B.

Regarding speeds, you're missing the point again. Yes, a mach 1.5 to mach 2 interceptor can down a mach 0.9 bomber reasonably reliably

While we are at this... if a plane could do 1.05 mach down low (100-200 feet), could a top speed at altitude (30,000-50,000 feet) be guesstimated or are there too many variables?

Regardless, the F4D-1 with it's speed would by the late 1950's adopt the following attack profile: A supersonic head-on pass would be initiated with rockets fired at a pre-determined range; should that fail, a tail-chase would be performed and thus the AIM-9's would come into play; should that fail, the guns would be used as last resort.

Regardless, the F-108 was ultimately built around intercepting a Mach 3 bomber -- I checked.  Admittedly I don't know where they concluded Mach 3 would be needed...

therefore for the interceptors to maintain any kind of speed advantage, they would need to be doing mach 2.8 or higher, with more effective missiles to boot.

The AIM-4's didn't have very good range though, admittedly they were better than the folding fin designs.

It's also a bit misleading to compare the performance of a naval fighter like the Skyray with that of a continental interceptor like, for instance, the F-106.

I didn't know that...

When defending a continent however, there are multitude of possible targets spread over thousands of miles, so if an attacking bomber switches targets and "dog-legs", it can force the interceptor to fly "cross range" for hundreds of miles just to get back into an intercept position. Thus the land interceptor needs more performance to cover it's "territory" than the naval one.

Just out of curiosity

1. The USAF had several ADIZ's set up that covered hundreds of miles out tracked by strings of radars right?

2. I assume interceptors would be launched as quickly as possible upon such a threat emerging; and I assume launches would be made from multiple bases (that happen to be in the strike range of the approaching bomber) to cover more airspace and prevent dog-leg attacks?

yes, I know, but those are small bits of the airframe, subject to local heating for a short time. If you want to sustain high speeds, you get into the problem of "heat soak" where heat conducts from the place where it's being produced and raises the temperature of the whole airframe.

I'm aware that airframes don't heat up instantly and soak up heat as they fly fast longer: I was under the impression that the F-106's leading-edge was made out of steel because the stag-point is the hottest section; the areas behind that are less hot and honeycomb aluminum is smoother, the regular aluminum behind that is subjected to cooler air.

Well the Soviets continued to deploy bombers with stand-off missiles in the anti-carrier role so the USN had to defend against them. It's also the fact that an aircraft carrier is the single highest-value target that can be detroyed by one strike with conventional weapons in a non-nuclear war, so it's worth spending hideous amounts of money defending it.

So the fact that they could do it without nukes is one reason they kept trying to do it.  What was the CEP's of their ballistic missiles at the time?

Sticking three of four AS-4s into New york would be horrible, but it wouldn't destroy New York.

Uh, they could carry a 350 kt to 1MT nuclear warhead... that would do the trick

By contrast, sticking them into the USS Nimitz, and sinking it, would be a national disaster.

With the regular 2200 pound warhead.

Regarding the Lightning, there was also the realisation that non-nuclear, sub-strategic conflicts like Korea and Vietnam were going to keep happening and needed to be planned and equipped for, and the Lightning could be useful in those scenarios.

When was this realized

Then NATO went over to it's Flexible Response strategy which envisaged a prolonged conventional conflict with the Soviets that may or (hopefully) may not end in nuclear war, and again, the Lightning could play a useful role in the defence of Germany.

And when did this idea come into play, like 1960-63 right?

So although the logic of the nuclear war "partial defence is no defence" argument continued to apply, the range of potential war sutuations expanded beyond that of all-out nuclear war.

That was a big step forward -- really the idea of nuclear deterrence was quite insane actually: Threatening to use your nastiest weapons first!

Wars are never cool, and they start out bad to begin with: Still there are usually restrictions at the start; assuming decisive victory doesn't happen very quickly, it just spirals into mayhem and all restrictions are lifted and anything goes pretty much to win; Deterrence involves not just threatening, but planning to do the worst from the beginning.

Basically it's either peace or all out war (for a few days)

[martinbayer]

Yes, but Walt Spivak was allegedly quoted in saying the plane was good to Mach 4, he was the Chief Engineer so his statement carries some weight.
[/quote]

Even (or perhaps especially) chief engineers are only human (at least in my personal experience, being an aerospace engineer myself), so Spivak may have been somewhat, shall we say 'biased' towards his own creation .

Martin

[KJ_Lesnick]

Martin Bayer

Even (or perhaps especially) chief engineers are only human (at least in my personal experience, being an aerospace engineer myself), so Spivak may have been somewhat, shall we say 'biased' towards his own creation .

Or maybe he was correct...

[Gondor]

Instead they misused the Phantom and the result was a severe curtailing of it's life.

How did the RAF misuse the Phantom?  I'm not really familiar with much about the RAF past WW2

The RAF used their Phantoms for ground attack and low level work which ate into their airframe life. Strengthening plates were added to the underside of the wing box to extend the aircraft's life later in their service life.

Indeed: might be an idea to call the F-4D the "Skyray" in future when you're talking about it since most people think of the Phantom when they see "F-4"....

Good point, but one could also say F-6A... prior to 1962 it was called the F4D-1, post 1962, it was called the F-6A; prior to 1962 there was the XF4H-1, the F4H-1F, and the F4H-1 which were known later as the XF-4A, the F-4A (no idea why no YF-4A), and the F-4B.

There never was an XF4H-1 nor XF-4A. The X is for Experimental and the Y for Protatype

Gondor

[martinbayer]

Martin Bayer

Even (or perhaps especially) chief engineers are only human (at least in my personal experience, being an aerospace engineer myself), so Spivak may have been somewhat, shall we say 'biased' towards his own creation .

Or maybe he was correct...

Maybe, maybe not .

Martin

[jcf]

Robyn, the stainless steel honeycomb structure of the XB-70 was not good for Mach 4.
The basic layout of the XB-70 may have been usable for a Mach 4 aircraft, but the
aircraft as designed and built was not capable of said speed. Again, I think you
are misinterpreting statements, and in this case apparently an anecdote which you
can't produce, and turning them into givens.

[KJ_Lesnick]

I was thinking about some items of interest

1. What was the projected range of the XF-103?
2. What range was needed to intercept a Mach 2 bomber (2-minutes to start the plane up and be on the runway; then takeoff, accelerate and climb to altitude and intercept speed, race out to the bomber and blow it away)?
3. What range was needed to intercept a Mach 3 bomber (2-minutes to start the plane up, be on the runway; then takeoff, accelerate and climb to altitude and intercept speed; race out to the bomber and blow it away?)


JCF

Robyn, the stainless steel honeycomb structure of the XB-70 was not good for Mach 4.

If I remember the statement correctly, he said the engines and inlets were good for mach 4 operation.

The basic layout of the XB-70 may have been usable for a Mach 4 aircraft, but the aircraft as designed and built was not capable of said speed.

Then what's the point of the J93?  As I understand it, the J93 was designed for WS-110 program, which ultimately became the XB-70.

The engine was needed to produce the necessary speed, thrust, and efficiency the plane required

• The General Electric X279E was the J93-GE-1: It was rated for Mach 4
  
• The J93-GE-3 and GE-5 were capable of the same mach numbers and greater thrust
  
• There is little value in designing a Mach 4 engine for a plane that can only do Mach 3: After all, designing for that speed would require more creativity in material-selection and air cooling, which is more expensive; a lower pressure ratio which could reduce efficiency of the engine, something highly undesirable in a plane where aerodynamics, inlet performance, and engine performance were to be maximized
  

The LRIX was originally built for speeds somewhere around 1.7 to 2.4, and from there it steadily increased right on up to around Mach 3.5 to Mach 4 with the engine capability going up, this at first included the J79 X-275; then the J93-GE-1; then the J93 GE-3

[Weaver]

Weaver

Absolutely even with a proximity fuse. The chance of a direct hit head-on was near to nil. Remember that the technical difficulties that bedevilled the homing systems also affected the fuses.

Because they work on the same principles, I get it...

We did however use intercepts that would involve a head on approach followed by an abeam approach correct?  That would lower closure rates down right?

Well obviously all intercepts have some element of "head-on" at some point, the question is whether you can shoot effectively during that phase.

The traditional approach was the curve-of-pursuit, where GCI would offset the interceptor to one side of the bomber's track, then at the right moment, the interceptor would turn in behind it. This therefore involves flying past the bomber, turning 180 deg, and then catching it up, all of which takes time. The measure of good GCI controller was how precisely they could set up the geomentry to minimise the time delay, but even if they were good, a well-timed evasive maneuver by the bomber could still throw it all off and add delay back in again.

The next approach was collision-course, where the fighter could point at the bomber from the side as you describe. This reduced time delay in theory, but in practice, weapon limitations reduced it's effectiveness. FFARs were hideously inaccurate and short-ranged (some fighters and bombers nearly collided on exercises) and missiles had two problems. Firstly, their guidance systems struggled to deal with a high-speed crossing target, and secondly, they either had to fly an energy/fuel inefficient curved path, or they had to try to "lead" the target which added yet more complication to be solved with 1950s electronics.

Head-on solved all these problems in theory, but it was only possible with non-nuclear warheads when the missile/radar technology had advanced sufficiently.

Regarding speeds, you're missing the point again. Yes, a mach 1.5 to mach 2 interceptor can down a mach 0.9 bomber reasonably reliably

While we are at this... if a plane could do 1.05 mach down low (100-200 feet), could a top speed at altitude (30,000-50,000 feet) be guesstimated or are there too many variables?

Too many variables. One of the limits on low-level speed is airframe strength. For instance, the MiG-25 can famously do Mach 3 (Mach 2.8 with missiles) at altitude, but at low level it's limited to Mach 0.78 by airframe considerations: slower than a Tornado F.3, which, due to it's origin in a low-level strike aircraft, could do Mach 1+ at low altitude. On Red Flag exercises, "subsonic" Buccaneers used to outrun "supersonic" Phantoms becuase at low level, the latters' airframe-limited speed was less than the Buccs' (this is also why the RAF's F-4Ms used up a lot of airframe life in their early years as fighter-bombers in RAF Germany).

Well the Soviets continued to deploy bombers with stand-off missiles in the anti-carrier role so the USN had to defend against them. It's also the fact that an aircraft carrier is the single highest-value target that can be detroyed by one strike with conventional weapons in a non-nuclear war, so it's worth spending hideous amounts of money defending it.

So the fact that they could do it without nukes is one reason they kept trying to do it.  What was the CEP's of their ballistic missiles at the time?

Not good enough to hit a carrier without using a nuke, which is a line you may want to have the option of not crossing.

Sticking three of four AS-4s into New york would be horrible, but it wouldn't destroy New York.

Uh, they could carry a 350 kt to 1MT nuclear warhead... that would do the trick

By contrast, sticking them into the USS Nimitz, and sinking it, would be a national disaster.

With the regular 2200 pound warhead.

Argggh - okay: "Sticking three of four conventional AS-4s into New York would be horrible, but it wouldn't destroy New York. By contrast, sticking them into the USS Nimitz, and sinking it, would be a national disaster."

The point I'm making is that a carrier is a high-value target that can be destroyed in one hit without resorting to nuclear weapons, which is why it's worth spending megabucks on F-14s and AIM-54s to defend it.

Regarding the Lightning, there was also the realisation that non-nuclear, sub-strategic conflicts like Korea and Vietnam were going to keep happening and needed to be planned and equipped for, and the Lightning could be useful in those scenarios.

When was this realized

On the 9th of April, 1961 at 11.21am precisely......

Then NATO went over to it's Flexible Response strategy which envisaged a prolonged conventional conflict with the Soviets that may or (hopefully) may not end in nuclear war, and again, the Lightning could play a useful role in the defence of Germany.

And when did this idea come into play, like 1960-63 right?

Flexible Response was first proposed by the Kennedy administration from 1961. It became formal NATO policy in 1967.

So although the logic of the nuclear war "partial defence is no defence" argument continued to apply, the range of potential war sutuations expanded beyond that of all-out nuclear war.

That was a big step forward -- really the idea of nuclear deterrence was quite insane actually: Threatening to use your nastiest weapons first!

Well you have to remember that Massive Retaliation was a product of the late 1940s when the West had the advantage in nuclear weapons and no appetite, post WWII, to pay for large conventional forces. At the time it was seen as a strategic balance between the West's atom bombs and the Soviet's massive armies. As the Soviets gained an equivalent level of nuclear capability, Massive Retaliation began to look more and more like an "everybody loses" strategy, which is why Flexible Response came along.