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.
> 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.
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.
"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.
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..
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.
> ...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.
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).
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.
> 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.
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.
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.
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.
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.
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.
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.
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.
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).
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.
"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.
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.”
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.
Readit News
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.
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.
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.
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.
https://en.wikipedia.org/wiki/Complication_(horology)
No longer can software engineers arbitrarily add bloat and just get away with it.
https://www.tomsguide.com/computing/cpus/new-benchmark-shows...
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.
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.
I highly recommend visiting it for anyone interested in this stuff. It's an amazing museum, and it's totally free!
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.)
[1] https://www.youtube.com/watch?v=9GhYBVM7UHQ
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..
That guy may have been me. I was pretty bummed, but quickly learned about its awesomeness (avionics-wise, anyway).
ICBMs also render other kinds of bombers obsolete and yet b52 and tu-95 are still around.
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.
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.
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?
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+.
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 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.
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.
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.
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.
Actually used on the BOMARC and D-21's ramjet engines- which is why you don't originals of their engines on display anywhere.
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.
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.
Cite: https://www.thespacereview.com/article/3677/1
https://www.generalstaff.org/CDA/Air/B-70/XB-70_Escape_Syste...
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 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.
https://imgur.com/a/yf-23-xb-70-above-GFZDaYy
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.
https://www.youtube.com/watch?v=Ib1EXdIam44
The AF museum is our modern history and society shown through the lens of the air and is insane in size.
(I tell my family that on every stop on our road trips & vacations.)
https://www.youtube.com/watch?v=WptDcLKTYSM
This small detail peaked my curiosity - did GE have white collar workers on the night shift? If so, that is super interesting to me.
The good old days.