B-70 Variants - a History that Never Was
 

The Air Force's history office just published a new official history on the XB-70 program, which you can read here:

https://media.defense.gov/2020/Nov/23/2002540204/-1/-1/1/B-70%20VARIANTS.PDF

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looks like Dreamtime - everyone chipping in with their latest idea....................

Why bother with a B 70 launching a Minuteman missile when a silo equally well and far cheaper?

The same reason they trialled dropping one out if the back of a C-5 - airborne alert.

A problem of the silo based Mx is that at of a response to an enemy 1st Strike - If a threat is inbound you can either use it or lose it, losing the option to let it play out out before responding. With an airborne response you can afford to wait till after the strike to assess and respond.

But isn't that the role of the SSBN force, you may ask.

Firstly the B-70 was in the era before Poseidon/Trident, secondly it would have provided redundancy, and a raison d’etre for SAC (which it subsequently lost).

My first thought was that using a Mach 3 bomber to launch an ICBM would be serious overkill, but then I remember that - at the time it was being tested - it was far and away the largest aircraft flying - something like 250 tons.
The C5 and 747 came along a few years later.

Yeah ORAC but you had Polaris at the time IIRC - 41 (!!!) SSBN's............

More a plan for the USAF to keep flying manned aircraft as part of the Triad.

You could also launch from anywhere, complicating the enemies opportunity to use ABMs.

what was the endurance?

Well, it had a range of over 3,700nm with a fuel load of over 300,000lbs and a cruise speed of M3.0.

So I imagine at subsonic loiter with a couple of engines shut down, plus a KCi-135 as an escort - lots....


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thats a great graphic - I'd never realised it was significantly bigger than a B-52

But if you're going to throw ICBM out of it I'd have thought endurance rather than top speed was a major requirement - otherwise you are likely to get caught on the ground.

One reason might be simply that the silo is in a known location and can't duck.

Wow, I had no idea it was that big. Must get over there to see it one day.

I've seen it a couple of times (Dayton) - and it is huge (especially for it's day - hard to believe they did that nearly 60 years ago - when we didn't know what we didn't know).
Word of warning - unless somethings changed, the XB-70 is in a remote building from the main museum buildings. You need to take a shuttle bus over and back - which has limited hours of operation.

It was in one of the main hangars when I visited in June, 2019.

same applies to a B-70 Airbase - they couldn't operate from any old field. That's why I was asking about endurance - if its limited then they have to spend a lot of time on the ground on Quick Alert. Also given the unit cost you could probably buy a lot of Minutemen silos for one ICBM equipped B-70

Good to hear - it's been about 10 years since I was there, I knew they were planning an expansion of the main buildings but didn't know the status.
However the first time I visited (around 2000), I spend a couple hours looking around the main museum buildings, but realized I'd not seen the XB-70 (and it's big enough it would be hard to miss), so I asked at a help desk. 'Oh, that's in the annex, you need to take a bus over. The last bus left 15 minutes ago....:uhoh:...

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Here she is

Same thing happened to me when I went to Kennedy Space Centre. I was absolutely gutted not to see the Saturn 5, as we spent so much time in the new Atlantis exhibit. I went back a few years later. Not disappointed.

Interesting how much they thought about dropping or launching stuff in supersonic flight as early as back then. The SR-71 even tested it.
Strange that those plans never seem to have materialized, say to launch ramjet-drones into contested airspace, at least it got never admitted.
Now extrapolate the same spirit and think what might be possible and done today?

Lovely aircraft. It was outside when I saw it mid 1980's