B-1A vs. B-1B

[Dayton Kitchens]

Also back when the Safeguard system was developed and deployed (briefly) vast amounts of the U.S. electronic infrastructure from B-52 bomber avionics to the entire air traffic control system to vast portions of the electrical grid were built out of old fashioned systems (including vacuum tubes) that was far, far, far more resistant to EMP than systems from the mid 1980s to today.

Heck back in the mid 1970s, you wouldn't have had to worry about cars not starting due to EMP because virtually none of them had electronic ignition systems.

 

[Herzen's love-child]

I could see the possibility of that happening, depending on the level of counter-EMP preparedness built into the launching side's RADAR sites. Of course, EMP is an oft-quoted side effect of nuclear initiations, despite the fact that most military-grade equipment in the nuclear/strategic arena is not only shielded but hardened (Silicon-on-Sapphire circuiting being one of the more use- and cost-effective methods).

It is now. It was a concern of even military grade systems well into the 80s.

Scratch that. It still is a concern. Critical systems are hardened, true, but enhanced ways of creating both nuclear and non-nuclear EMP have made it an ongoing issue.

 

[Riain]

The Soviet's would work on developing a counter. However I suspect that any counter to the B-70 would have been much more difficult to build than the counter to the B-1 bomber. The B-1 was relatively easily countered with radar and Aircraft that could simply look down and fire at a target trying to fly low and fast. .

Given that all major air powers followed the low level route and abandoned high level, high speed penetration, including the Soviet Union, I'd suggest that this speaks volumes about the relative combat effectiveness of the two approaches. If mach 3 was the way to win wars at least one of the major powers would have pursued that approach instead of abandoning it in it's earliest days.

I like your use of the term 'simply' when talking about look down shoot down, as if this wasn't a major technological hurdle that was overcome with great difficulty.

 

[FleetMac]

Given that all major air powers followed the low level route and abandoned high level, high speed penetration, including the Soviet Union, I'd suggest that this speaks volumes about the relative combat effectiveness of the two approaches. If mach 3 was the way to win wars at least one of the major powers would have pursued that approach instead of abandoning it in it's earliest days.

I like your use of the term 'simply' when talking about look down shoot down, as if this wasn't a major technological hurdle that was overcome with great difficulty.

Aaaand you'd be wrong. Much of what this really speaks to is the "it MUST be better" effect, wherein somebody looks at the experiences of another country's tactics or technology and adopts it without paying attention as to the reason it worked. It's why the Russians went to the 5.45mm round after American experiences in Vietnam despite there being measurably better and more effective rounds to try out. It's why the US adopted so many features of the FG-42 rifle into the M-60 (and look how THAT turned out). It's a constant feature of the Cold War in particular, where one side would develop a new jet or adopt new tactics, and the other side would immediately copy it instead of analyze how or why it'd work. Also, the Soviet Union never dropped hi-altitude approaches, just look at the MiG-25/-31 or Tu-160; they're all hi-altitude, relatively fast-approach combat planes whose doctrine and tactics never reflected that sort of "nap-of-the-earth" approach as a general rule.

As to why nobody adopted Mach 3 designs, two words; Vietnam. War. It sorta had this neat trick of SUCKING UP FUNDS and R&D, not to mention manpower, and totally butt-f**ked aerial tactics up until the 1990s with low-altitude nonsense. Look at aerial warfare nowadays; the only time that sort of approach is even used anymore is for close-air support runs.

 

[Riain]

Low level was chosen as the preferred means of penetration before the Vietnam war hotted up. The reasons aren't difficult to understand, high altitude aircraft can be detected by high power radars from hundreds of miles away, giving plenty of time to work out an intercept solution. From there the rest is just rocket power and warhead size, which the SA5 had in spades.

At low level detection ranges drop to dozens of miles due to the curvature of the earth, what's more the earth itself causes a complex radar picture which increases the effectiveness of jamming. I don't know why people can't seem to accept these basic facts.

 

[FleetMac]

Low level was chosen as the preferred means of penetration before the Vietnam war hotted up. The reasons aren't difficult to understand, high altitude aircraft can be detected by high power radars from hundreds of miles away, giving plenty of time to work out an intercept solution. From there the rest is just rocket power and warhead size, which the SA5 had in spades.

At low level detection ranges drop to dozens of miles due to the curvature of the earth, what's more the earth itself causes a complex radar picture which increases the effectiveness of jamming. I don't know why people can't seem to accept these basic facts.

And modern hi-altitude aircraft can in turn detect BEING detected (warning annunciators and such) and work out COUNTER-maneuvers to the defenses. This isn't WWII where airborne radar was a rudimentary technology relegated to night fighters, the SA of the incoming attackers is hardly simplistic. Actually, here is a much more detailed breakdown of the SAM-Bomber dynamic in terms of an intercept probability (cribbed from an essay on the HPCA Forum):

"Most reference sources on missiles give two pieces of data on range. One is maximum range, the other is maximum ceiling. The critical thing to remember is that these figures are mutually exclusive. Achieving one precludes the achievement of the other. If the maximum range of a missile is 100 miles and its ceiling is 150,000 feet, it's range (when measured as a horizontal distance from its launch point) when fired to 150,000 feet will be zero. It goes straight up and come straight back down.

So, the critical point is not what a missile's maximum range or altitude is, but what its range is when fired at a target at a specific altitude. These figures are mostly strictly classified. However, it takes a lot more energy to climb than it does to fly level so...that range decreases sharply as altitude goes up. A measure of how sharply can be determined by dividing the missile's horizontal range by its vertical range; this gives a rough indication of the ratio it takes to make a missile go up as compared to along. For most missiles, this energy ratio varies between 8:1 to 3:1.

The key here is the launch kinetics of the missile. A very energetic missile will burn its fuel fast, giving it a low energy use ratio that allows it to climb fast and have a larger range at high altitude. But, by burning its fuel fast, it loses horizontal range. A less energetic missile will burn its fuel more slowly giving it a greater horizontal range but it will have an unfavorable energy ratio and thus will have a limited range at higher altitudes.

Now, add into that manoeuverability. Missiles that depend on fins for manoeuvering (pretty much all off them until very recently) have a problem in that their small control surfaces are ineffective in the thin air at high altitudes. What may be a very agile missile in the thick air low down, are barely capable of manoeuver high up. Aircraft with their much larger control surfaces are effected to a lesser extent.

The effect of all these considerations is that each type of missile has an effectiveness graph of range against altitude that isn't a simple cylinder, its shaped like a lemon standing on one end. It has a narrow base (determined by radar horizons), swells out quickly as altitude increases then tapers off to a long thin spike at the top. If the altitude of the bomber is plotted across that lemon, it gives a cross-section of a circle, the radius of which is the range of the missile at that altitude. In order to score a hit, the missile crew must fire their missile so the target is within that circle at the time the missile reaches that altitude. In order not to be hit, the bomber shouldn't be in that circle. The smaller the circle, the easier it is for the bomber to change course and not be there. Also, the faster the bomber is, the less time it takes to cross that circle and thus the narrower the time window for the missile to be in the right place at the right time.

Even if the bomber is within the circle, it still is far from certain it'll get hit; that depends on the agility of the bomber versus the missile, the destructive radius of the missile warhead and the capability of the electronic warfare equipment on the bomber. This probability of a kill is called PK and missile producers like to claim PKs of anywhere from 80 to 100 percent. In the real world, 20 percent is doing very, very well and few missiles get that high. One gets around that by firing a lot of them........

Applying this to the B-70, even against missiles theoretically capable of reaching 150,000 feet, the missile range at 77,500 is so much smaller that the bomber has an excellent chance of being able to not be within that radius. At Mach 3.4 (37.3 miles per minute) even if it is within that radius, its vulnerability window is very small, a matter of a few seconds. Even if the missile is capable of getting to the B-70 in that time window, its chance of scoring a hit is pretty low.

By the way, the fastest anti-aircraft missile in the world today is capable of a tiny hair over Mach 6. That means it has a speed advantage over a B-70 of around 1.75. To have a marginal capability against a target, a missile is required to have a speed advantage of 2.0. This implies that the best anti-aircraft missiles in the world today have only a very marginal capability against a B-70 type target.

Compare this with OTL; in OTL there has never been a successful attempt to intercept an SR-71 Blackbird (claims to have done so are either fictitious or wishful thinking). The B-70 flies higher than an SR-71, its significantly faster, is much more agile and has much better EW capabilities. And the B-70 shoots back.

In terms of numbers, the defense needs the following:

2.0 Speed Advantage and 1.0 Altitude Advantage for 25% pK
3.0 Speed Advantage and 2.0 Altitude Advantage for 50% pK
4.0 Speed Advantage and 3.0 Altitude Advantage for 75% pK
5.0 Speed Advantage and 4.0 Altitude Advantage for 90+ pK

So this means that when the SA-2 or it's equivalents come out in 1957, having a mach 2.0 (1,320 MPH) capability, this puts at severe risk the B-36J, having a 50% pK against it, due to having a 3.21 speed advantage over it, but against the B-52D, which flies 200 MPH faster, the SA-2's pK falls to 25%, since it only has a 2.08 speed advantage.

Against the B-70, the SA-2 doesn't even have a chance, it's advantage ranges from 0.67 to 0.59 depending on whether the Valkyrie is at Mach 3 cruise or Mach 3.4 combat speed.

When the SA-5 (S-200) enters the picture in 1967, it's Mach 4.5 (3,000 MPH) speed allows it to gain a 50% pK on the B-52D, but still can't begin coming close to killing the Valkyrie, as it's advantage is only 1.51 to 1.34.

When the SA-10 (S-300P) comes around in 1978 with its 3,800 MPH (Mach 5.75) speed, it's advantage rises to 1.92 to 1.69; it's still not really enough to gain a 25% PK on the Valkyrie.

Finally, when the SA-20 (S-300PMU-1) hits the market in 1992 with a 4,690 MPH speed (Mach 7.02), it can achieve an advantage of 2.37 to 2.09 against the Valkyrie, marking the first time a 25% PK is achieved against the B-70.

Of course, this is with historical missile development, e.g. trying to retain some sense of sanity in regards to dimensions. The enemy could simply say "screw this, I want a missile that can hit Mach 7 now" in the 1970s if he's willing to accept a massive increase in missile size, which decreases the amount actually available to the defense at any site, imposing virtual attrition. If you have to go from 4 SAMs on a TEL to just 2 in order to get a reasonable advantage over the B-70, the Valkyrie has killed half your missiles before he even shows up through said virtual attrition.

There are two additional factors that have to be included. One is electronic warfare; once an aircraft is in the engagement envelope of a surface-to-air missile, it depends on its electronic warfare capability to reduce the missile's PK. In this environment, bombers have a significant advantage because they have the power and internal capacity to carry fairly comprehensive EW systems.

The other is systems behavior. The SAM's (along with the fighters and everything else) fit into an air defense environment which has a built-in reaction time due to the delays inherent in its configuration. If the threat to that system develops faster than the system can respond to those threats, then the threat gets inside the reaction time of the system and said system falls steadily behind what is actually happening.

Missiles have the plus that they come in very, very fast so the defense system has a limited time to react. However, the problem with missiles is that they have no means of changing or developing their threat. They're coming in on a known ballistic arc and their position on that arc at any given time is predictable. That means the defense system doesn't have to react to them; it can predict what and where the threat will be at any specific time and then reacts to that predicted threat. In other words, it's inherent within the nature of the operational scenario that the defense system is far ahead of the threat. Since missiles don't - and can't - have defensive EW systems of their own, that makes them very, very vulnerable. The only problem is exploiting that vulnerability.

With manned, Mach 3.4 bombers, no such predictions can be made; the flight path of a manned aircraft is, by definition, not predictable. It can turn, climb or dive plus it can use its built-in electronic warfare capability to ensure (hopefully) that the defense system is receiving false data. So the bomber is ahead of the defense system. This was something that took us a lot of hard work to convince people of when we were consulting on the design of air defense systems; the performance of the system as a whole is much more significant than the performance of any one component of the system. Improving one (for example buying F-16 interceptors to replace F-5Es) makes only a limited difference to the performance of the system as a whole. If, using that example, the improved performance of the interceptor is to be exploited, the whole system has to be upgraded with faster communications links, better operational display systems, better surveillance and target acquisition systems etc. If all those good things aren't done, the air defense system effectively has F-16s performing to F-5E levels. (It works the other way as well of course; if the interceptors cannot match the performance of the ground-based environment, then the added performance of that environment is wasted. So, a ground based environment that can exploit F-16 performance but only has F-86L interceptors doesn't have any advantage over an environment designed around the F-86L.)"

 

[Just Leo]

Compare this with OTL; in OTL there has never been a successful attempt to intercept an SR-71 Blackbird (claims to have done so are either fictitious or wishful thinking). The B-70 flies higher than an SR-71, its significantly faster, is much more agile and has much better EW capabilities. And the B-70 shoots back. [/I]

The XB-70 spent one hour and 48 minutes at mach 3, including 20 minutes at up to mach 3.08, during the entire program, and AFAIK, did not carry offensive or defensive weapons, nor was the effectiveness of any electronic countermeasures verified. The final years of testing were limited to mach 2.67, or somesuch. The range was limited to 5500 mi from 7700 mi with the dropping of zip fuel due to severe problems. Just sayin'.
For a B1A thread, there's not much about it.

 

[FleetMac]

The XB-70 spent one hour and 48 minutes at mach 3, including 20 minutes at up to mach 3.08, during the entire program, and AFAIK, did not carry offensive or defensive weapons, nor was the effectiveness of any electronic countermeasures verified. The final years of testing were limited to mach 2.67, or somesuch. The range was limited to 5500 mi from 7700 mi with the dropping of zip fuel due to severe problems. Just sayin'.
For a B1A thread, there's not much about it.

That's technically true for the first test model. The second (and designed third) were quite a bit more capable, as shown HERE. And given the disparity in abilities between YB-52s and the production follow-ons, I'm hitting the "I BELIEVE" button on this one.

 

[Herzen's love-child]

Compare this with OTL; in OTL there has never been a successful attempt to intercept an SR-71 Blackbird (claims to have done so are either fictitious or wishful thinking). The B-70 flies higher than an SR-71, its significantly faster, is much more agile and has much better EW capabilities. And the B-70 shoots back.
]

You seem to be confusing what was hoped to be achieved by the end of a development process that never happened with what actually saw the light of day. In the real world, the SR-71 had a slightly higher service ceiling than the XB-70. 85,000 feet compared to 77,000 feet. Significantly faster? Not in what was actually built. Better EW suite? Not developed and implemented into what was actually built. Remember, the program was cancelled in '61, definitively so in '62 despite the best attempts of LeMay and Congressional allies to reinstate it. What was built was never going to be developed further, being relegated to general high speed aeronautical research.

I mean, c'mon, making claims of paper aircraft? There is a long history of designed but not built aircraft with incredible paper specifications but that never were built or if built, never achieved it in the real world. One can claim anything about such fancies.

Furthermore, substantiated claims about intercepts of the SR-71 and if they were achieved or not are out of the public domain (still). Unless you are privy to such classified information, you don't really know and I don't really know, one way or another. There is only rumor and web tales. I'm partial to the Swedish stories about achieving radar locks on SR-71s during the Cold War. Did they really? No one with authority is talking.

 

[FleetMac]

You seem to be confusing what was hoped to be achieved by the end of a development process that never happened with what actually saw the light of day. In the real world, the SR-71 had a slightly higher service ceiling than the XB-70. 85,000 feet compared to 77,000 feet. Significantly faster? Not in what was actually built. Better EW suite? Not developed and implemented into what was actually built. Remember, the program was cancelled in '61, definitively so in '62 despite the best attempts of LeMay and Congressional allies to reinstate it. What was built was never going to be developed further, being relegated to general high speed aeronautical research.

I mean, c'mon, making claims of paper aircraft? There is a long history of designed but not built aircraft with incredible paper specifications but that never were built or if built, never achieved it in the real world. One can claim anything about such fancies.

Furthermore, substantiated claims about intercepts of the SR-71 and if they were achieved or not are out of the public domain (still). Unless you are privy to such classified information, you don't really know and I don't really know, one way or another. There is only rumor and web tales. I'm partial to the Swedish stories about achieving radar locks on SR-71s during the Cold War. Did they really? No one with authority is talking.

The same way you fancy about "enhanced" ways to create EMP, despite the fact that much of what "EMP" does is conflated from SREE and TREE effects that don't always come into play with nuclear weapons use? The paper aircraft argument doesn't fly, as the majority of individual components that went into such projected capabilities WERE built (hell, the B-1A had a derivative of the XB-70's bomb nav radar) and can thus be somewhat estimated in terms of performance. If you don't believe me, check out Dennis R. Jenkins and Tony R. Landis' excellent "VALKRYIE: North American's Mach 3 Superbomber" (ISBN-13 978-1-58007-130-7) which includes much of the peripheral and notional included technology of the aircraft program.

It is true that some of what we glean from a notional B-70's performance is speculation to be sure, but how is that any different from doing the same with other projects that met the same fate? If we're gonna try going back to the OP (unfortunately the thread has strayed a bit ), I repeat what I mentioned about the Tu-160 being identical to the B-1A design instead of the -B. If it works for them, it could work for us (based on their operating experiences with it, of course).

 

[Herzen's love-child]

The same way you fancy about "enhanced" ways to create EMP, despite the fact that much of what "EMP" does is conflated from SREE and TREE effects that don't always come into play with nuclear weapons use? The paper aircraft argument doesn't fly, as the majority of individual components that went into such projected capabilities WERE built (hell, the B-1A had a derivative of the XB-70's bomb nav radar) and can thus be somewhat estimated in terms of performance. If you don't believe me, check out Dennis R. Jenkins and Tony R. Landis' excellent "VALKRYIE: North American's Mach 3 Superbomber" (ISBN-13 978-1-58007-130-7) which includes much of the peripheral and notional included technology of the aircraft program.

It is true that some of what we glean from a notional B-70's performance is speculation to be sure, but how is that any different from doing the same with other projects that met the same fate? If we're gonna try going back to the OP (unfortunately the thread has strayed a bit ), I repeat what I mentioned about the Tu-160 being identical to the B-1A design instead of the -B. If it works for them, it could work for us (based on their operating experiences with it, of course).

Not my fancy about enhanced EMP weapons (nuclear and not) which are generally acknowledged to be of interest and an object of research among the US, Russians, Chinese, and who knows who else.

Your last statement re, the TU-160 and the B1A is at least relevant to the OPs original query. It would indeed be more fruitful to get back on track in discussing that.

 

[FleetMac]

Right *CRACKS KNUCKLES*

Personally I'm of the opinion that the B-1A could, and should, have replaced the majority of B-52s in service in the mid-late 1970 timeframe so as to replace airframes that were getting worn out and less able to conduct airborne deterrence OR conventional ARCLIGHT raids. The funny thing is, even the B-1A could conduct low-altitude insertion tactics AND higher-altitude raids without too much of a drop in performance. True it wouldn't be as "stealthy" as the B-1B, but compared to its aerial performance over range that's an acceptable trade-off for me. Meanwhile, the payload and range advantages over the FB-111 make the latter an acceptable plane to kill off.

I know somebody will bring up the maintenance hours needed to upkeep a swing-wing design like the Lancer, but reducing the Aardvark fleet on the whole should help with that (not to mention cutting the entire D-fleet of Stratoforts, whose only useful attributes were the RIVET RAMBLER ECM upgrades anyway). HERE is a useful comparison on the -52s and notional B-1A characteristics (again, extrapolated from actually-built gear and designs).

 

[kessock]

Point of fact, American Sprint ABMs (part of the two pronged Safeguard system of the early 1970s) which were designed to intercept ICBMs at altitudes of about 100,000 feet had warheads of FIVE MEGATONS IIRC.

But they were not designed to kill warheads by explosive force (thought that would've been nice). The massive warheads were designed to produce a neutron burst (enhanced radiation warhead) that disabled the incoming warheads.

Your confusing the Sprint and Spartan. Spartan had the 5MT exo-atmospheric warhead that destroyed by X-Ray flux. Sprint was the indo-atmospheric missle that had the low KT warhead that destroyed by neutron flux.

 

[Delta Force]

If we're gonna try going back to the OP (unfortunately the thread has strayed a bit ), I repeat what I mentioned about the Tu-160 being identical to the B-1A design instead of the -B. If it works for them, it could work for us (based on their operating experiences with it, of course).

Just because it's tangential doesn't mean it's not interesting. The B-70 and FB-111 were the predecessors and competitors to the B-1A, after all.

 

[Dayton Kitchens]

Your confusing the Sprint and Spartan. Spartan had the 5MT exo-atmospheric warhead that destroyed by X-Ray flux. Sprint was the indo-atmospheric missle that had the low KT warhead that destroyed by neutron flux.

My apologies. That does make more sense.

By the way, IIRC, the Sprint missiles and warheads were actually kept available in storage all the way up to the end of the Cold War.

Theoretically, they could've been reactivated relatively rapidly.

 

[Dayton Kitchens]

Just because it's tangential doesn't mean it's not interesting. The B-70 and FB-111 were the predecessors and competitors to the B-1A, after all.

Not really. The B-70 was meant to be a B-52 replacement. Because the B-52 was supposed to be just an "interim" bomber. A big "bomb truck" that could haul the mail for a few years until a true supersonic bomber (B-70 it turned out) came along and replaced it.

The FB-111 was merely a longer wing F-111 that was plumbed to carry a couple of SRAMs in its small internal bomb bay (and four more under the wings though this would be unlikely).

The F-111 of course came about from one of the worst procurement messes in U.S. military history.

But,

The FB-111 was a long time favorite in SAC because it out performed the B-52 almost EVERY TIME in the competitions for bombing accuracy.

 

[Pomphis]

At Mach 3.4 (37.3 miles per minute) even if it is within that radius, its vulnerability window is very small, a matter of a few seconds. Even if the missile is capable of getting to the B-70 in that time window, its chance of scoring a hit is pretty low.

Maybe. But what is stopping the SU from developing a mach 3 Bomarc

http://en.wikipedia.org/wiki/CIM-10_Bomarc

and firing three or four from different directions at a B-70 ?

With nuclear warheads you don´t need a direct hit. And I am pretty sure that one could buy quite a few of them for the price of a single B-70.

When the US decided to cancel the B-70, they already had an operational Bomarc. I assume they looked at the possible performance of a B-70 versus the possible performance of a Bomarc successor 10 years later too.


The IM-99A had an operational radius of 200 miles (320 km) and was designed to fly at Mach 2.5–2.8 at a cruising altitude of 60,000 feet (18 km). It was 46.6 ft (14.2 m) long and weighed 15,500 pounds (7,000 kg). Its armament was either a 1,000 pounds (450 kg) conventional warhead or a W40 nuclear warhead (7–10 kiloton yield).

The first IM-99B was launched in May 1959, but problems with the new propulsion system delayed the first fully successful flight until July 1960, when a supersonic KD2U-1/MQM-15A Regulus II drone was intercepted. Because the new booster took up less space in the missile, more ramjet fuel could be carried, increasing the range to 710 km (440 mi). The terminal homing system was also improved, using the world's first pulse Doppler search radar, the Westinghouse AN/DPN-53. All Bomarc Bs were equipped with the W-40 nuclear warhead. In June 1961, the first IM-99B squadron became operational, and Bomarc B quickly replaced most Bomarc A missiles.[16] On March 23, 1961, a Bomarc B successfully intercepted a Regulus II cruise missile flying at 100,000 ft, thus achieving the highest interception in the world up to that date.

 

[FleetMac]

BOMARC is certainly a beast, no doubt about that. However, after plugging those max figures into a nuke calculator, you get a blast radius of about 3.3 square miles at 100,000 ft. And at a straight-line speed of about 37 miles a second for the Valk, how much engagement window does that give a BOMARCski? The intercept you mention is certainly nothing to sneeze at, but it's worth mentioning that a drone (even a badass one like the Regulus-II would be) doesn't bank, jam or pre-emptively nuke the launch site on the fly (no pun intended).

 

[Pomphis]

You have to get close, yes, but OTOH you can launch multiple interceptors from different directions and the B-70 must evade all of them.

Plus the B-70 had turbojets and needed afterburners to get to mach 3. With 46,745 gallons fuel and a fuel consumption rate of 51 g per kNs

http://en.wikipedia.org/wiki/North_American_XB-70_Valkyrie#Specifications_.28XB-70A.29
http://en.wikipedia.org/wiki/General_Electric_YJ93

I get less than an hour at full speed. Either it´s no longer a long range bomber, or it has to fly mostly at lower speeds.

 

[Pomphis]

And at a straight-line speed of about 37 miles a second for the Valk,

There must be a mistake. That would be 133,200 mph.