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The XB-70 (2019)

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Re: The XB-70 (2019)

#71

Post by runjake »

FpUser wrote: post #67
nradov wrote: post #58

Earlier quoted context omitted.

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…

>"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. Besid…

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.

Re: The XB-70 (2019)

#72

Post by justinator »

runjake wrote: post #44
loloquwowndueo wrote: post #29

Earlier quoted context omitted.

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.

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 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.

Re: The XB-70 (2019)

#73

Post by ge96 »

FpUser wrote: post #67
nradov wrote: post #58

Earlier quoted context omitted.

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…

>"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. Besid…

> 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

Re: The XB-70 (2019)

#74

Post by nradov »

FpUser wrote: post #67
nradov wrote: post #58

Earlier quoted context omitted.

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…

>"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. Besid…

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.

Re: The XB-70 (2019)

#75

Post by rayiner »

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.

Re: The XB-70 (2019)

#76

Post by recycledmatt »

jiggawatts wrote: post #56
runjake wrote: post #4

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 o…

> 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…

They would be busy ferrying troops and supplies. Amateurs talk about tactics, professionals discuss logistics!

Re: The XB-70 (2019)

#77

Post by spankalee »

runjake wrote: post #71
FpUser wrote: post #67

Earlier quoted context omitted.

>"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. Besid…

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…

> 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.

Re: The XB-70 (2019)

#78

Post by skhr0680 »

retrocryptid wrote: post #42
mandevil wrote: post #9

Earlier quoted context omitted.

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 d…

They tell the most pernicious lies about radiation.

Fun fact: The real-life inventor of the neutron bomb, Samuel T. Cohen, loved “Repo Man”!

Re: The XB-70 (2019)

#79

Post by hollerith »

rayiner wrote: post #75

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.

Re: The XB-70 (2019)

#80

Post by jiggawatts »

nradov wrote: post #62
jiggawatts wrote: post #56

Earlier quoted context omitted.

> 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…

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.…

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...

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