As someone who once worked on B-52s, I find it amusing how many "successors" it has outlasted. And I know why, because I worked on many of those, too.
It has taught me to be skeptical of unproven claims and promises, especially when someone is particularly passionate about them. Also that simplicity is king. Complexity is the enemy.
I have great respect for the XB-70. It's the only strategic bomber I haven't worked on or even seen in person, and it holds a certain "alternate reality" mystique for me.
> Also that simplicity is king. Complexity is the enemy.
I don't know anything about B-52s, but I work on a project where we are essentially replacing a 40 year old weapon system with a new one. The new one should of course do the same things, preferably better, and do additional new things. The old system started out simple, but has since had most of its internals swapped both hardware and software wise a number of times. We have full access to all the documentation of the old system, but let's say there has been periods throughout these 40 years where this aspect hasn't exactly been top priority.
It doesn't come as a surprise to me that projects like JSF end up a complete clusterfuck. Everyone tends to underestimate the complexity of the system they operate/produce after a while because most of it is always there and just works.
There’s an urban legend in NYC that every incoming mayor since something like 1890 gets a letter, handed down from mayor to mayor, signed by all of the mayors, that says something like, and I am guessing here, but it is supposedly a very short letter:
Do not #%{>€!# with the sewer system. You may be tempted to, because it works so well it is invisible, to reduce its budget, or to overhaul it, or something.
Do not.
Fund it. Hire extremely competent people to run it, and do not replace them.
Do not #%*|!%# with the sewer.
> Also that simplicity is king. Complexity is the enemy.
As someone that has managed engineering teams for large projects, I 100% agree. One of the issues with computers IMO is that it has made bad engineering easier. Back when you had to check everything with a slide-rule, you had a real appreciation for the skill and engineering prowess and experience to make things absolutely dead simple.
One of my favorite things is in the watch world, every mechanism besides showing time is called complication. When one talks about a feature, or an item as a complication, just the act of doing that forces one to be more deliberate.
I like to say that whatever the complexity is, it is in the nature of the problem itself and isn’t something that’s open for us to design. Only when we design a solution we risk introducing complication.
Of course, we can always choose to solve the least complex problem.
True, but also modeling and iteration does lead you to unexpected solutions that can in turn solve complex problems that you couldn't have imagined could be solved. Landing rockets being an easy one, but that kind of iterative approach has been put to work in all kinds of fields.
One of the sources of this, which is now over, was the exponential increase in computing power. You could add complexity and your code would always run faster anyway, one of the popular benchmarks saw worse results on average than last year which never happened before. There are a lot of reasons for it some more speculative than others, and clearly computers will get faster in the future. But still.
No longer can software engineers arbitrarily add bloat and just get away with it.
https://www.tomsguide.com/computing/cpus/new-benchmark-shows...
"Also that simplicity is king. Complexity is the enemy."
That's what worries me about a lot of the shiny, super high tech, super expensive weapons systems of the US. These are fine against an overmatched enemy when you can fly back to a safe place for doing the necessary maintenance. This may change when there is a war against a capable enemy that can strike closer to home. The US has always had the advantage that the homeland was safe but that may change in the future. And once you lose a B-2 bomber it's very hard to replace.
It's literally impossible to replace a B-2 bomber: the production line was shut down years ago and much of the supply chain no longer exists. Existing B-2's (there are only 19 still in service) will be gradually replaced by new B-21 Raiders.
One of the long standing problems with US defense procurement is that they build a batch of something, then cut off all orders and dismantle the production line in order to free up funds to develop a successor model. This is tremendously risky because it leaves a gap of many years when it's impossible to replace attrition losses. If the US is going to maintain a credible deterrent against China then something has to change. Either defense spending has to go up or we have to drastically scale back activities in other areas. And no, cheap AI drone swarms won't replace the capabilities of something like a B-21.
>"If the US is going to maintain a credible deterrent against China then something has to change. Either defense spending has to go up or we have to drastically scale back activities in other areas. And no, cheap AI drone swarms won't replace the capabilities of something like a B-21."
Assuming the US would actually need B21 capability in a war with China. Those will be probably blown up from the sky very fast. Besides I doubt wars with China and / or Russia will be limited to conventional means. Will probably escalate to nuclear very fast and then everybody is royally fucked.
Nah. Everything we know about the B-21 indicates that it's probably pretty survivable against the Chinese air defense system. Especially for stand-off strikes near the Taiwan Strait where it wouldn't have to overfly radar stations. The design was literally optimized for exactly that purpose.
Ironically the B-21 is probably safest in the air. The greatest kinetic threat is on the ground because forward air bases generally lack hardened aircraft shelters or effective missile defense. This is another reason why maintaining deterrence against China will require a major increase in defense spending or realignment of priorities.
The whole point of procuring a platform like the B-21 is to never have to use it. The strategic calculus is that just having it gives the US a range of conventional options short of global thermonuclear war, and thus forces adversaries to be more cautious.
It's hard to believe the B-21 would ever be stored at a forward missile base.
They'd likely take off from the US, fly wherever they need to go for their mission without landing, and then fly all the way back to the US. Same as the B-2.
Similarly it's unlikely a drone strike is an issue due to distance.
> It's hard to believe the B-21 would ever be stored at a forward missile base.
Not a "missle base", but: "The B-52...is one of two currently at RAF Fairford in England as part of a routine Bomber Task Force (BTF) deployment." [0]
Also, more pertinent to location in scope, US has been increasing forward-based capabilities in south pacific, for example [1].
[0] https://www.twz.com/air/b-52-flies-close-to-border-of-russia...
[1] https://www.twz.com/air/massive-wwii-b-29-bomber-base-fully-...
I should not have said "missile base". I just meant any kind of forward base outside the US.
The B-52, etc.. is just different. It's not as high value of an asset as the B-2 or the B-21 will be and gets treated differently.
The Air Force already periodically deploys B-2's to forward bases within range of Chinese missile strikes.
https://www.pacom.mil/Media/News/News-Article-View/Article/2...
Current plans are to purchase a relatively large number of B-21's. Some losses are expected and accepted.
Believe it. Forward basing would be the only way to generate useful sortie rates in that type of conflict. Transiting even from Hickam just takes too long and requires too much tanker support. We're already short of tankers; they're wearing out and not being replaced quickly enough.
The greatest kinetic threat is from drone swarm attacks, which can be delivered to the vicinity of an airbase from a handful of anonymous-looking trucks or vans.
One or two grenade-strength shrapnel devices are enough to make a $700m dollar special project useless.
How does a truck drive to Diego Garcia?
There is a major shipping lane that runs SE of Diego Garcia.
https://www.marinetraffic.com/en/ais/home/centerx:72.1/cente...
You could try a surprise drone attack from a container ship. Looks like the closest ship is about 125 miles away, that might be pushing the range a bit.
I think any war with China would be predominantly economic and cyber. I don’t think it’s viable for either party to perform a mainland strikes and I don’t think it would become nuclear, but who knows. If things escalate during the current POTUS’s term, I think it will come down to meetings and deal-makings, because that is POTUS’s passion and preferred way.
I think any war with Russia would be, well is, economic and cyber and proxy wars.
> I think it will come down to meetings and deal-makings, because that is POTUS’s passion and preferred way
Current POTUS is an egomaniacal moron. Things could very easily get out of his control, especially as he dismantles the US government and sources of influence throughout the world.
> because that is POTUS’s passion and preferred way.
Just like he surrendered Ukraine to Russia. An amazing deal for everyone involved, except Ukraine.
>"I think it will come down to meetings and deal-makings, because that is POTUS’s passion and preferred way."
Don't you think it looks more attractive than going up in flames?
> Those will be probably blown up from the sky very fast.
Why do you say that? I'd think B21 is better (stealthier) than B2. I think there is a story about a B2 dropping a dud on NK undetected granted NK vs. China
They have one at the Air Force museum in Dayton.
I highly recommend visiting it for anyone interested in this stuff. It's an amazing museum, and it's totally free!
They don't have "one". They have the only one. The other one built crashed in 1966. The one in Dayton is all there is.
When I saw it, an SR-71 was parked under one of its wings. Talk about a stellar presentation of aviation engineering magnificence.
That's a YF-12, not SR-71 but indeed very similar
https://www.nationalmuseum.af.mil/Visit/Museum-Exhibits/Fact... I'm not really into this kind of thing but this museum is truly fascinating; I second the recommendation wholeheartedly
Not only is the museum itself awesome (and free), they are also responsible for almost every US warplane on display around the world. You can download a spreadsheet from their website showing where planes are on "loan".
One of my favorite photo renderings of the XB-70: https://erik-simonsen.pixels.com/featured/xb-70-valkyrie-und...
A good look at the XB-70. No narration, just highly detailed pictures.[1]
The XB-70 looks like nothing that came before, and nothing after it looks like the XB-70. Six engines side by side in the tail. It looks like a 1950s concept for a spaceplane. It was apparently a good aircraft, but expensive and didn't fit any military need of the time.
(The need for high-altitude supersonic bombers declined once surface to air missiles got good enough to hit them.)
I agree with you, but the issue afaik is that B-52 was more flexible whereas the B-70 was basically single purpose and basically obsoleted by ICBMs.
B-52s were able to pivot to new roles so have stayed around.
I'm humbled for us laughing at the one guy assigned to B-52 maintenance role when was in USAF training over 30 years ago "That old thing? Ha!". Who would have guessed..
> I'm humbled for us laughing at the one guy assigned to B-52 maintenance role when was in USAF training over 30 years ago "That old thing? Ha!".
That guy may have been me. I was pretty bummed, but quickly learned about its awesomeness (avionics-wise, anyway).
You may find this amusing then. I was at Travis for a day (from McClellan) and I had time to stop by their museum. They had a G model on display and there was an older gentleman with a child looking at it. "What kind of plane is this, grandpa?" "I'm not sure - I think it's a cargo plane"
I had a really tough time resisting the urge to tell them the "cargo" came out the bottom.
Ha, at Lowry in 1993?
Yep, up until January 1993 or so.
"SRAM Howell" ring a bell?
Ah I got there 1/93 so may have missed. I remember going to "fundies", getting called "pinger", etc. Good times.
Nobody can understand our fear of washing out and moving to the other side of the dorm to become a food handler and serving your former avionics classmates breakfast. This happened a lot while I was there.
Lol, I forgot all about that - though there were some cute chicks over there. I remember chatting with one about her upcoming French Toast test :-)
What killed the xb-70 was the advent of better air to air missiles that nullified its high-altitude high-speed flight advantage.
ICBMs also render other kinds of bombers obsolete and yet b52 and tu-95 are still around.
> ICBMs also render other kinds of bombers obsolete and yet b52 and tu-95 are still around.
This has been proven utterly false since the 1960s, because a) you can't recall an ICBM after firing it, b) you can't retarget an ICBM after firing it, and c) there's no reliable way to tell nuke warheads from conventional ones, meaning every one you launch has to be assumed to have a nuclear payload, with all the world-ending consequences that entails.
The Air Force resurrected this zombie idea (conventional ICBMs) in the 2000s and called it Prompt Global Strike, only to can it for the obvious reasons.
We also live in a world where Russia launches conventionally armed IRBMs against their neighbor.
https://en.m.wikipedia.org/wiki/Oreshnik_(missile)#First_ope...
It was not conventionally armed. It had dummy training warheads, conventional payloads for it are not even being developed. There are hardly any targets for which lobbing high explosive with an ICBM is cost effective.
> There are hardly any targets for which lobbing high explosive with an ICBM is cost effective.
Unless your neighbor has effective air defenses and you want to make a political point...
From what I know, what actually killed the XB-70 was ICBM advancements.
The B-52 survived by becoming a low altitude bomber and an excellent, cheap nuclear-capable cruise missile delivery platform that was comparatively cheap to operate at the same level of effectiveness as the B1-B and B-2A for similar roles.
Russia more or less mirrored this with the Tu-95.
The B52 was never a low altitude bomber, you're thinking of the B1A, which was to be a high altitude, super sonic bomber but SAM missile tech advanced faster than the development of the bomber could happen, and it was canned, before being resurrected as a subsonic, low altitude bomber (the B1B). The XB-70 couldn't make that switch because it was a ridiculous design (for starters).
The B52 role was to have wings (and nuclear bombs) in the air constantly over the arctic to act as a deterrent. The only way that idea could attempt to survive out of the 50's is if they (or one of them) were < hour from a target at all times. They're huge, they flew slow, and their flight path didn't change much. The whole multi-decade mission was a huge waste of money; a stage drama.
The B52 also became a heavy bomber in Vietnam, with incredibly heavy loses. The Air Force in general in Vietnam was a shit show -- observe the F4.
It's only when you have air superiority can you dredge up a B52 to deliver a payload.
These are not winning strategies in a war that would start today by an adversary like China. We're going to be caught with our pants down with B52s as the stains on our underwear.
> We're going to be caught with our pants down with B52s as the stains on our underwear.
Meanwhile: their entire imported food and oil supply has been easily blockaded by ancient, conventional systems.
> observe the F4
Isn't there a truism that the F4 demonstrates that with big enough engines, you can get any lump of junk up into the air ?
The way I heard it, ‘with enough power, even a brick will fly’
The Vietnam era is totally different. LeMay and Powers were sociopaths whose goal was to nuke things and intercept things that would nuke the US. Survivability wasn’t really a consideration - assuming you finished nuking the Soviets, there would be nothing to return to.
The needs of Vietnam required different tactics, and the airmen paid in blood for the myopic vision of the leaders.
Eh, the B52 has survived because it is amazing at being a bomb/missle/etc. dumptruck, and doesn’t have anything fancy which is expensive to maintain or particularly brittle.
Even the airframes are mostly still alive 50+ years later, which is mind blowing on aircraft. They have made a new B52 since ‘62 but they keep on trucking.
It isn’t super fast (the B1 is that), or stealthy (B2 or B21), or sexy (B1), or nimble (any of the generations of fighter bombers that have come and gone). It doesn’t fly particularly low. Or particularly high.
But god damn can it carry and drop absolutely massive quantities of whatever type of ordnance you want, pretty much anywhere you want on the globe, and do it over and over and over and over again. 70,000 lbs worth
The 737 is still around for pretty much the same reasons.
Any alternative ends up being less effective at the same tasks, or more niche/expensive.
They’re basically the alligators or horseshoe crabs of the airplane world. Or the M2 heavy machine gun. Or the Cessna 182 or Robinson R22 of the GA world.
Or the Avro Vulcan - now sadly relagated to a single example that can only taxi a bit.
KISS should always be #1 engineering principle, in any engineering. In software one I can speak a bit, the unnecessary complexities always bite back. Maybe not the creator of them, but given company always. Or as one quite bright guy said - 'this should be as simple as possible, but not simpler'.
But its borderline boring, nothing shiny, nothing to sell new subscriptions or trainings for, nothing to get promotions for, things that just keep running (TM) slip out of focus. Look at how brilliant engineers handle boredom and routine - usually very, very badly. Its not what 'hackers' want to do, despite thats exactly what all normal companies want to get. Unprofessional for sure, but when most of potential and otherwise brilliant employees have issues with this, they tend to get some slack.
I was watching a documentary about 20 years ago and they said "It may not be your father's air force but it may be your father's air plane."
Not to make this thread about the B-52, the thing has been operational long enough for 3 generations from one family to fly it: https://www.dailymail.co.uk/news/article-2430802/David-Welsh...
> ...especially when someone is particularly passionate about them.
The engineer-type brain is very much prone to "... in order to prove we can," as opposed to "Because we should. Or because this is useful. Or because this even does the job claimed."
Across a range of fields. A/B testing "engagement hacks" falls into this category, as far as I'm concerned. It was certainly successful at the stated goals.
When the project started a Mach 3 strategic bomber that out of the reach of surface to air missiles, and that could hit multiple targets on its way, was a huge advantage. It was obsoleted by ICBMs and better antiaircraft weapons, but it was still a hugely successful development program. It just didn’t provide a useful plane, but helped develop all the parts for future ones.
Well, as i understood it has failed because it could no longer provide the main benefit over B-52 it was initially intended to provide: high-altitude penetration - over it's development time, engagement envelope of SAM systems expanded in altitude and speed so much that even XB-70 could no longer hope to get through. So it wasn't any better than B-52, except much pricier. It could also get to the target faster, but for applications where time of flight was critical, nothing could beat an ICBM anyway. They switched to cruise missiles - to keep B-52s out of harm's way, and low-altitude penetration (B-1B), then when radars became capable of discerning things vs ground reflections too well, they switched to stealth - but Soviet Union fell apart before they knew if it could work or not.
So it's not about any technical failures of XB-70 itself, just that it turned out to be unable to do the job it was planned for.
Wrong?
This seems unlikely just because the SR-71 never got hit with a missile.
They might have been afraid of the XB-70 getting hit but it likely never would have just because it turned out to be so hard to hit things at 70,000+ feet traveling at Mach 3+.
I am in awe of anyone who worked on bringing forth such projects into the world. In the mean time, in my little corner of the world, a team of people are struggling to conjure up a relatively "simple" website.
I always wondered why the B-52 didn’t get replaced by converted airliners (787 has quite similar dimensions I believe). Would be much cheaper to run and could do practically the same thing, no?
There was thought given to using 747s as cruise missile carrier aircraft.
Each 747 CMCA would have carried dozens of AGM-86 nuclear-armed cruise missiles on rotary launchers that shuffled around the plane's cargo bay on rails (the missiles would be ejected one at a time from a small door near the rear of the fuselage).
Which was an interesting idea, but it eventually evolved into a much much better one:
I read something about those systems, they really have that already in service? Damn.
Those kind of system would be really „cheap“ to deploy, you overwhelm a lot of air defense systems with it and well it’s transportable outside of air defense range.
Rapid Dragon is using cargo aircraft for cruise missiles.
They look the same to a layman, but they are very different airframes, with a different wing sweep and different load capabilities, among many, many other differences.
of course the b-52 is a completely different airframe. Just wondering what the reasons are you wouldn't be able to convert airliners to be used in that role. It's been done for fire bombing!
not really.
> Also that simplicity is king. Complexity is the enemy.
Which sounds good, but the B-52 planes used eight very old jet engines each that are complex to maintain.
Rolls Royce offered to replace these with four modern turbofan engines but were turned down.
They finally relented and there’s a new program that will run to the end of the 2030s(!) to replace the eight engines with… eight engines.
This doesn’t sound simple, or cheap.
I keep pointing out to people that if a real world war broke out, every country with a commercial wide body fleet will immediately convert them to bombers. Far cheaper, far simpler to maintain, and with much faster turnaround times / lower maintenance hours per flight hour.
You can't replace them with 4 engines because those will have to be of bigger diameter and they might scratch the ground of some less than perfect airfields. The engines HAVE to fit into the same nacelles. And they have to provide enough thrust while having same diameter -> this is hard because the goal of replacement is efficiency, and you replace a low-bypass engine for a high-bypass to increase efficiency, which means that hot section must be smaller, and thus able to survive more heat and pressure.
Previous programs of B-52 re-engining indeed, tried to replace 8 engines with 4. It never worked because of diameter/ground clearance issue. They had to wait until progress in aircraft engines allowed for the engine of same diameter to provide the necessary efficiency boost.
By the way, re-engining will vastly reduce air refuelling needs, and further extend airframe life because of lighter takeoff weights, as they won't need to take as much fuel on most missions. And in a pinch, almost any mission will be doable without refuelling at all.
In a peer war it's pretty damn dubious whether a B-52 with four modern engines will be more survivable than a B-52 with 8 antiques. Either way the most they'll be able to do is launch standoff munitions from a distance they hope will keep them safe, and if it doesn't then they're dead anyway. In a scenario short of that, we're just quibbling over the degree of waste American voters will put up with (it's the military, so the answer is a lot.)
That's pretty much irrelevant. Engine replacement is about increasing range and/or reducing tanker requirement/airframe wear, and reduction of maintenance costs because existing engines are ancient and their maintenance costs are high. One of the reasons this program has been postponed for so long was retirement of C-141 that left USAF with plenty of still good TF-33s. But now these are starting to run out too.
You're right, I intended to reply to the comment saying "In war, only capability matters. Nothing else". I don't think the engine replacements would/will meaningfully sway the balance of capabilities.
It's always disappointing to see such uninformed and yet overconfident comments on HN. Replacing the eight small B-52 engines with four larger ones was considered and rejected years ago because it would have forced much more extensive modifications to the airframe and other systems.
https://www.twz.com/6825/engine-falls-off-b-52-during-a-trai...
And it's extremely difficult to convert civilian airliners into bombers. The pressure hulls aren't designed around bomb bays and they lack external hard points. Even though the P-8 is based on the 737 the design had to be extensively modified to accommodate weapons through a major program lasting years. The resulting aircraft are new production, not modifications of airliners.
You're saying that my argument that "8 engines is not simple" is invalid because... it would not be simple to replace them with modern efficient engines... because there are 8 of them.
Yes. We agree: the setup is not standard, not simple, and requires 2x the maintenance that 1/2 the engines would for decades and decades.
Older and established isn't necessarily "simpler" or "cheaper".
The average annual maintenance cost of a B-52 is $70 million.
The maintenance cost of a 747 or a similar sized plane is more like $4 million, and they operate far more hours than the B-52 fleet.
A commercial plane equivalent to a B-52 costs something like $200M to purchase new, which is just three years of maintenance for a B-52!
Sure, sure, the out-of-the-box default for a commercial wide-body airliner is not immediately usable as a strategic bomber, but it's not that hard to add a bomb bay, in-air fuel port, etc...
You are comically off-base on this, man.
We are talking about a nuclear bomber. They put fucking nukes on these things. We have 70 years of operational history showing that the 8 engine arrangement works, and there is no good reason to make anything more than the most minimal changes. Go ahead and do that until you're blue in the face with some inconsequential junk SaaS product or phone app or whatever, but warplanes (and especially this one) are not the place to do it.
I'm just going to hope you're not actually serious about converting a commercial airliner to a bomber.
The bomber isn’t nuclear.
The payload is.
The good reason to make changes is the hard reality that your opponents won’t slow down to accomodate your old, inefficient, maintenance-heavy fleet of bombers.
Even during peacetime the B-52 fleet is burning money, money that DOGE assures the voting public cannot be wasted on frivolous matters such as HIV prevention.
It’s like the Ukraine war. Perfectly good tanks turned out to be useless sitting ducks in the face of $500 drones.
Why change anything?
Because the enemy did.
Because the rest of the world did.
If your assessment of role of armor in Ukraine is that it's useless because of drone developments, you're just not playing with a full deck of cards.
You can think what you want and I can't stop you, I just want to say that you shouldn't bring this up around people that do real engineering (especially in aerospace and defense) unless you want to look like an idiot.
Wow, you're really doubling down on the aggressive ignorance. Do you have any clue about what's involved in certifying a platform for the nuclear strike mission?
Making such a plane, yes, I have a pretty decent clue. It's not that hard. It was done with early 1950s technology!
Certifying, sadly... also yes. I work in government.
Do you think the enemy cares whether you're properly certified or not?
Similarly, do you think hackers care if your CISO has all of your security audit paperwork nicely rubber stamped?
Do viruses care if your unpatched servers have been officially exempt from the update schedule?
In war, only capability matters. Nothing else.
There's quite a bit of extra hardware needed on the aircraft for the nuclear mission. As well as testing for stuff like weapons separation. None of that is easy or cheap on converted civilian designs.
You would know this if you had bothered to do some basic research instead of posting ignorant and irrelevant comments. Like many arrogant engineers who love to pontificate about topics outside your area of expertise, I'm sure you're convinced you're right and everyone else is an idiot. So I'll pass on any further replies and let you believe that you "won".
Go do the research yourself please and link to articles that explain why carrying a cruise missile with nuclear warhead instead of a high explosive warhead adds $60M in annual maintenance costs to each active bomber.
They would be busy ferrying troops and supplies. Amateurs talk about tactics, professionals discuss logistics!
That era of aviation was nuts. I wish I was around for it. Men with slide rules working out the limits of material science, aerodynamics, and everything else, all at once. Because it wasn't enough to just push one limit, you had to push half a dozen others to get things to that first limit. And the rate of advance was just staggering.
The XB70 flew in late 1964. Concorde was doing revenue flights in 1976, cruising at Mach 2, with passengers being served luxury food.
> The Air Force learned that pushing the technological envelope resulted in plane that was difficult to build, difficult to maintain, difficult to fly, and perhaps even more importantly, was incredibly expensive; the program cost nearly 1.5 billion dollars, or around 11 million dollars per flight.
And nothing has changed. Pushing the limits is expensive. Always has been, always will be.
My favorite bit of design from this era went something like this: "ooohhh, we need something that can handle high heat. How about if we made it radioactive?" and so Mag-Thor was born (https://en.wikipedia.org/wiki/Mag-Thor): Magnesium plus Thorium. It's creep resistant up to 350C! And it's only mildly radioactive! That's not a problem, right?
Actually used on the BOMARC and D-21's ramjet engines- which is why you don't originals of their engines on display anywhere.
Mag-Thor is interesting it actually has rather poor overall thermal characteristic compared to most metals since its melting point is only circa 650c pretty much the same as magnesium but it basically shrugs any heat upto 350-400c depending on the alloy so it doesn’t changes its dimensions or becomes susceptible to mechanical deformation (it’s basically as hard at 350c at it is at room temp). So it’s useful but only for very specific applications unlike say titanium. And today we have super alloys like inconel which can hold back heat creep up to 650c and it’s annealing starts at almost 900c.
They tell the most pernicious lies about radiation.
Fun fact: The real-life inventor of the neutron bomb, Samuel T. Cohen, loved “Repo Man”!
The sheer amount of gas this plane must have carried in order to fulfil its mission…
Per Wikipedia, the XB70 carried: 300,000 pounds (140,000 kg) / 46,745 US gal (38,923 imp gal; 176,950 L), on a maximum takeoff weight of 542,000 lb - so about 55% of takeoff weight was fuel.
A 747-8I carries up to 63,034 gallons, or about 400k pounds, on a max takeoff weight of 987,000 pounds, or about 42% of takeoff weight.
Interestingly, the ranges are about the same. The XB70's combat radius (there and back) is 3,725 nm, for a straight line range of 7450 nm, the 747-8I's range is 7730 nm.
High altitude supersonic flight is actually fairly efficient... if you can handle it.
Was the XB-70 capable of inflight refueling? On a quick look, I can’t tell if that was the plan, or if it was going to be a one-way trip (optimistically landing in Turkey or something to refuel, but realistically…).
I don't believe it was capable of it, which is why it was so massive. The SR-71, which required inflight refueling repeatedly, only held 80k pounds of fuel (about 12k gallons). I don't have any good sense of fuel burn vs speed either, but in general, jets like to run high and fast. The old Lear 23s burned about as much fuel (pounds per hour) idling on the ground as they did at cruise, and I think the SR-71 (which mostly used the turbojets to keep the afterburners lit, at cruise...) fuel economy up high was quite good. Apparently the major problem with performance was keeping it from overspeeding - left to their own devices, the engine (... entire engine assembly, however long it was) was running so efficiently that they just wanted to go.
The actually built XB-70's- the two prototypes- did not have a refueling receptacle. Production models would have had a boom receptacle just like the B-47, B-52 and B-58 did. It would have gone in the upper fuselage about where the delta wing starts.
And not just any gas: https://en.wikipedia.org/wiki/Zip_fuel
What ended the XB-70 was SAM's, not ICBM's so much. It was much easier for the Soviets to build and deploy the SA-5 Gammon (aka the S-200 Angara, basically a perfect a B-70 killer) than it would be to build and operate a significant fleet of B-70's.
This was actually so clear to the USAF that about five years after the B-70 was canceled (about the time the first XB-70 took flight), when the Soviets actually started to deploy thousands of SA-5 across the Soviet Union, the USAF was convinced it must have ABM capabilities. It wouldn't make sense for the Soviets to use ~10% of their annual concrete production to defend against a threat that the US had already canceled, so they thought that the SA-5 had to be a super-useful national ABM capability (they had already evaluated that the ABM-1 system under construction around Moscow, the so called Triad system, as overmatched by the existing Minuteman I deployments, but thousands of missiles required more even more thousands of warheads to exhaust). In response, the USAF suddenly expressed significant interest in MIRV technology, and the Minuteman III program began, and ICBM warhead numbers started to get really insane.
The ejection capsule design for the XB-70 is some next level engineering. Your seat would move backward into a capsule before ejection to survive the cruising altitudes of 70k feet / Mach 3.
https://www.generalstaff.org/CDA/Air/B-70/XB-70_Escape_Syste...
That is a really good explanation and reference. I like those old documents.
I have a love/hate relationship with this plane.
In 2014 I got to visit the AF Museum in Dayton, OH. With all the exceptional exhibits there it is completely obvious the XB-70 is THE crown jewel in that museum.
And it snowed while we were visiting and they shut down the hangar with the XB-70 because it required a shuttle ride.
So now I still have on my bucket list to see it.
I went in 2010. Took the bus onto the air base to the experimental plane hangar. We only had 1 hour. I could have easily spent 3 hours there.
I mainly wanted to see the YF-23 but here's a pic I took with a fisheye lens of the back of the YF-23 with the XB-70 above. I think they have since moved the planes to a different hangar.
I have a love/hate relationship as well, mostly because I grew up within bicycling distance and spent way too much time at the museum.
The XB-70 used to be parked outside right in front of the main entrance. The cool thing is they also have the X-3, which seems like the same design family so you can see the test article then the attempt at a usable aircraft.
It was also the location of one of the most bonkers thing I've ever seen which was when they relocated an SR-71 to the museum and landed it on this very short old runway at the site. That thing was so big and so fast and that runway even at the time seemed so short. Here's a vid. I saw it from the road off the end of the threshold and it looked like it was going to hit the fence on the landing pass.
we lived in rona hills for about 4 years. not biking distance, but close enough to visit frequently. and as a youngster they let me conduct the AF orchestra there at the AF 25th anniversary. Very good memories.
Whoa. Aircraft carrier approaches, just without arresting wires.
The AF Museum is probably the best air museum in the world. Of course, you have the Smithsonian in DC, but the size limits and general audience they expect really tones it down. You end up with a couple insane exhibits (Command Module, X-15, Wright flyer) but they all feel out of context. I actually preferred the annex with the Shuttle more.
The AF museum is our modern history and society shown through the lens of the air and is insane in size.
Go back, it's so worth it. I stood under those six massive turbojets and looked up in absolute awe. It's a miracle that they didn't cut it up for scrap and left a really fabulous museum piece when the project ended.
Because we're not the British or Canadians who felt they had to make their military R&D decisions irreversible by destroying all the evidence (e.g. TSR2, Avro Arrow, etc).
In fact there is a TSR-2 at the Imperial War Museum Duxford.
It was a violation of orders as all airframes were explicitly ordered to be destroyed and burned.
Always good to have a reason to return.
(I tell my family that on every stop on our road trips & vacations.)
The only time I went to the AF Museum was in the early 80s while in grade school. I still remember that thing. It was the coolest thing I'd ever seen. I was completely floored.
It's back in the main exhibit now AFAIK. They completed a 4th hangar some years back and towed it back there:
"got a job with the Flight Propulsion Division of General Electric in Evendale (just outside of Cincinnati), initially working night shift in the Controls and Accessories department... the engine required the efforts of hundreds of engineers to design everything from a new turbofan and compressor, to new fire-suppression systems, to a special high-temperature fuel. Exactly what part my dad worked on is unclear; I always thought it was an oil pan, but my older brother was sure it was an oil pump."
This small detail peaked my curiosity - did GE have white collar workers on the night shift? If so, that is super interesting to me.
Yes, there is often manufacturing engineers on duty 24/7 and of course, line management.
At that point in the story, the dad didn't have a degree yet. I know _a lot_ fewer people did back then, but it's not entirely clear to me that he was working a white-collar job at that point.
“…Eisenhower, the newly-elected president, was working on something a little bigger: a national security policy to counter the growing Soviet military threat in Europe.”
The good old days.
This, if anything, understates how weird the XB-70 was; in particular it skims right over https://en.wikipedia.org/wiki/Zip_fuel
Dissatisfied with the progress, though, just weeks later the Pentagon canceled the HEF-3-powered J93 engine program and limited the Valkyrie program to the use of JP-4 fuel only. Testimony by USAF scientists before Congressional committees revealed that the technical hurdles and the operating cost of using HEF-3 as a jet fuel were prohibitive given the defense budget of the day.
I've seen the XB-70 at the Dayton Air Force Museum and each time it seems both massive and relatively svelte. Like some kind of shape that I can't quite fully understand. Really cool plane to see, especially among all the other aircraft from that era of aviation.
The Cold War era was the dream of engineers of all participant countries, I figured. Are we close to another one? Just wanna make sure it doesn't turn into a hot one.
yup, there was just so much money flowing around. it was like the dot com era for aeronautical engineers and machinists.
I remember seeing this beast at the Air Force 25th anniversary in '72 at wright pat. Pretty sure the one I saw didn't ever fly again.
The one you saw was the only one left after the insane accident that destroyed the other. It is still on display in Dayton.
A beautiful plane, shame those 6 engines in line is unreal to see.
Similar vibe would be the B1-lancer for engine although in 2s
The Wings Over the Rockies museum on the east side of Denver CO has a B-1A (!!!) on display. Landing gear is really tall, you can walk under the wings to see the engines.
I watched a really cool walk around video of it on YT
It's crazy it can carry as much payload as a B-52 if I recall right
The have a XB-70 at the Wright-Patterson USAF Museum in Dayton. I was blown away looking at the engines. Highly recommended museum if you're into aviation, it's huge so give yourself plenty of time.
The 1960s airplanes sometimes seem anachronistic. Both the XB-70 and SR71 were mach 3+ airplanes that flew in 1964. That was five years before the 747.
We no longer needed the XB-70 when ICBMs got good (basically when they changed from liquid fuel to solid fuel).
We no longer needed the SR71 when reconnaissance satellites got good.
Does anyone know why they went for six engines rather than four bigger ones? Was there a specific reason for that config?
Got chills seeing the first pic. What a beautiful piece of machinery.
Beautiful! Both the story, and the aircraft.
I normally do not read blogs. Yours is different. I loved your stories. Salut to your dad. Life well lived. Also thanks for pointing to Vivian Della Chiesa. Listened few songs on Youtube - great artist.
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