US Next Generation Bomber Studies

[DrRansom]

So is that subsonic or supersonic airframe?

I guess that is the question about the LRS-B: supercruise or not? I'm tending to think that it'll be something in the same weight class as the TU-22, but with stealth and supercruise, but that's just a WAG.

 

[RyanC]

I'm tending to think that it'll be something in the same weight class as the TU-22, but with stealth and supercruise, but that's just a WAG.

I have to agree with you -- Tu-22 is 90~ tonnes MTOW; vs 216 tonnes for a B-1B; and almost twice as much as the FB-111A's 54 tonnes.


That gives you a lot of room to play with (90 tonnes); yet it's significantly smaller than a full sized heavy strategic bomber; and thus has lower R&DTE costs including acquisition. That's going to be a key driver for everything we buy in the future -- cost -- as we are entering a cost constrained era.

 

[phrenzy]

Out of interest, what was the MTOW of the fb-22? Somewhere around the f-111 if I remember correctly, that's got to be short of what they are after... maybe a twin fb-22 ala f-82?

 

[TomS]

Yeah, the usual figure for the FB-22 was 54 tons MTOW, so right there with the F-111.
I've been thinking that the ideal weapon stowage for LRS-B would be a bay around 8-9 meters long and about 2 meters in diameter. That's sized for two small rotary launchers one in front of the other, each with four stations for 2000-lb weapons; or a single Massive Ordnance Penetrator (though that might stay a B-2 weapon, since it's so scarce). Total internal warload would be a max of 14 tons (for the MOP) but more usually 8 tons plus the rotary launchers. That's eight 2000-lb JDAM, JSOW, or JASSM or at least 32 SDBs. Maybe also have four external hardpoints for longer-range standoff missiles, if and when...

 

[sferrin]

Yeah, the usual figure for the FB-22 was 54 tons MTOW, so right there with the F-111.
I've been thinking that the ideal weapon stowage for LRS-B would be a bay around 8-9 meters long and about 2 meters in diameter. That's sized for two small rotary launchers one in front of the other, each with four stations for 2000-lb weapons; or a single Massive Ordnance Penetrator (though that might stay a B-2 weapon, since it's so scarce). Total internal warload would be a max of 14 tons (for the MOP) but more usually 8 tons plus the rotary launchers. That's eight 2000-lb JDAM, JSOW, or JASSM or at least 32 SDBs. Maybe also have four external hardpoints for longer-range standoff missiles, if and when...

Way too small if they're looking to replace the B-52 and B-1B with it.

 

[Steve Pace]

The USAF released RFPs for the Long Range Strike-Bomber (LRS-B) on 9 July 2014. -SP

 

[TomS]

Way too small if they're looking to replace the B-52 and B-1B with it.

Well, the question is whether we actually need bombers that big. How many weapons have these aircraft actually delivered in a typical sortie?

 

[sferrin]

Way too small if they're looking to replace the B-52 and B-1B with it.

Well, the question is whether we actually need bombers that big. How many weapons have these aircraft actually delivered in a typical sortie?

None. Not one has ever dropped a nuke in anger. I guess we don't need bombers. How many SLBMs have we ever launched in anger? ICBMs? Guess we don't need those either. Not trying to be a smartass but we never needed the capability to drop a MOP either - until we did. Unless you have some kind of time machine, and can see everything that's going to happen in the next 50 years, I'd prefer we didn't intentionally short-change ourselves.

 

[TomS]

You kind of jumped way past what I was saying. I never said we don't need LRS-B, but I think we need to think carefully about how much load capacity we really need and what we can afford.
There are two ways to lose future capability. One is to underdesign and leave too small growth margins. The other is to overdesign and escalate the unit cost beyond affordability. Given that we have a "silver bullet" B-2 force to handle the highest end missions requiring the biggest weapons or extremely large number of weapons, I think I'd aim for a mid-range LRS-B design that is less likely to bust the budget.

I can't imagine anyone seriously proposing a weapon larger than MOP (there's already a major push to go smaller), so using that as the upper bound for weapon weight seems logical. The other driving requirement is probably numbers of aimpoints to be struck per sortie. We did have cases in Bosnia of B-2s delivering all 16 large JDAMs in a single mission, but that was back when JDAM was a low-density asset and the B-2 was the only delivery option. Now that there are lots of delivery aircraft, we don't seem to be seeing as many such missions.

The one issue that makes me second-guess the numbers is the desire to have an assortment of weapons on hand when doing loitering on-call suport. Maybe we need a little more capacity so you can have a mix of SDB for small targets, large JDAMs for larger structures, and WCMD for anti-armor work. Fortunately, WCMD is fairly short, so it could be doubled-up on a rotary launcher for a 2000-lb JDAM without too much extra length (total length for the rotary would need to be around 5 meters each).

 

[sferrin]

You kind of jumped way past what I was saying. I never said we don't need LRS-B, but I think we need to think carefully about how much load capacity we really need and what we can afford.
There are two ways to lose future capability. One is to underdesign and leave too small growth margins. The other is to overdesign and escalate the unit cost beyond affordability. Given that we have a "silver bullet" B-2 force to handle the highest end missions requiring the biggest weapons or extremely large number of weapons, I think I'd aim for a mid-range LRS-B design that is less likely to bust the budget.

I can't imagine anyone seriously proposing a weapon larger than MOP (there's already a major push to go smaller), so using that as the upper bound for weapon weight seems logical. The other driving requirement is probably numbers of aimpoints to be struck per sortie. We did have cases in Bosnia of B-2s delivering all 16 large JDAMs in a single mission, but that was back when JDAM was a low-density asset and the B-2 was the only delivery option. Now that there are lots of delivery aircraft, we don't seem to be seeing as many such missions.

The one issue that makes me second-guess the numbers is the desire to have an assortment of weapons on hand when doing loitering on-call suport. Maybe we need a little more capacity so you can have a mix of SDB for small targets, large JDAMs for larger structures, and WCMD for anti-armor work. Fortunately, WCMD is fairly short, so it could be doubled-up on a rotary launcher for a 2000-lb JDAM without too much extra length (total length for the rotary would need to be around 5 meters each).

You seem to be overlooking one of it's primary functions - nuclear deterrence. The B-52 can hit 20+ aimpoints. The B-1B could have hit 38 (24 SRAM + 14 AGM-129). The SRAM 2 would have allowed the B-1B to hit 36 aimpoints with internal weapons alone. That's the size we need if we don't want to lose capability. Start shrinking aircraft size you either sacrifice the number of weapons or the size. Your mini-bomber won't carry 20 AGM-129 sized weapons. What's cheaper, 2 bombers that can only carry 10 each or 1 that can carry 20? The "well we haven't needed it yet" metric is probably the worst one could pick. We've yet to fight a near-peer. We're barely into the "pacific pivot" (which will only make the need for a larger aircraft more pronounced). We've yet to have to fight a nuclear war.

 

[TomS]

Nuclear warfighting is clearly secondary -- LRS-B may not even be nuclear-capable in its first tranche.


And frankly I don't see a plausible nuclear warfighting strategy that requires huge numbers of nuclear warheads delivered by bombers. Just because Cold War warplans called for 24+ nuclear weapons on a single bomber does not necessarily mean that current strategies will. I could just barely imagine using manned aircraft to deliver a small number of nuclear weapons, but in an unrestrained exchange with large numbers of aimpoints, ICBMs and SLBMs are going to have done so much damage that bombers are just going to be bouncing the rubble.

 

[sferrin]

Nuclear warfighting is clearly secondary -- LRS-B may not even be nuclear-capable in its first tranche.

Per an article in this week's AvWeek it will be.

And frankly I don't see a plausible nuclear warfighting strategy that requires huge numbers of nuclear warheads delivered by bombers. Just because Cold War warplans called for 24+ nuclear weapons on a single bomber does not necessarily mean that current strategies will. I could just barely imagine using manned aircraft to deliver a small number of nuclear weapons, but in an unrestrained exchange with large numbers of aimpoints, ICBMs and SLBMs are going to have done so much damage that bombers are just going to be bouncing the rubble.

I have a hard time getting on the, "let's sacrifice capability because I can't imagine a need for it" bandwagon. We'll just have to agree to disagree.[/quote]

 

[TomS]

I've seen too many programs explode financially (F-22, DDG-1000, etc.) because the procurement authorities kept asking for everything and didn't stop to think about what they actually needed most. At some point we actually have to start buying affordable, good-enough systems that we can buy in sufficient numbers to sustain force structure.

 

[sferrin]

I've seen too many programs explode financially (F-22, DDG-1000, etc.) because the procurement authorities kept asking for everything and didn't stop to think about what they actually needed most. At some point we actually have to start buying affordable, good-enough systems that we can buy in sufficient numbers to sustain force structure.

That's just it though. What you consider "good enough", I do not. Ultimately it's the war fighter who will decide. And besides, it's not aircraft size / payload that breaks the bank, it's the "we want all these new gizmos that don't exist yet" combined with screwing up schedules and requirements every year that do. The B-2 wouldn't have been $2 billion a pop if they hadn't gone, "whelp, the Cold War is over so cancel that sucker". As it turned out, even if it'd had a 135 ft wingspan it'd still have cost $2 billion each because so much of that figure was R&D.

 

[DrRansom]

We still have that Air Force research program from the mid noughts, there the conceptual bomber was:

20,000lb payload
2,000nm range at Mach 2 cruise

If the LRS-B was sized with a 20,000lb payload, would that be sufficiently large for you, Sferrin? That's about a fourth of the B-1B's internal payload.

 

[bobbymike]

Nuclear warfighting is clearly secondary -- LRS-B may not even be nuclear-capable in its first tranche.

Per an article in this week's AvWeek it will be.

And frankly I don't see a plausible nuclear warfighting strategy that requires huge numbers of nuclear warheads delivered by bombers. Just because Cold War warplans called for 24+ nuclear weapons on a single bomber does not necessarily mean that current strategies will. I could just barely imagine using manned aircraft to deliver a small number of nuclear weapons, but in an unrestrained exchange with large numbers of aimpoints, ICBMs and SLBMs are going to have done so much damage that bombers are just going to be bouncing the rubble.

I have a hard time getting on the, "let's sacrifice capability because I can't imagine a need for it" bandwagon. We'll just have to agree to disagree.

[/quote]

Quote - Every LRS-B will be nuclear-capable and it will be nuclear-certified two years after it enters service.

The LRS Family of Systems definitively includes a new cruise missile, and at a symposium in Washington this month, Lt. Gen. Stephen Wilson, commander of U.S. Air Force Global Strike Command, stated that the nuclear-tipped version will take priority over a conventionally armed missile.

 

[marauder2048]

Probably difficult to really debate the desired nuclear capabilities of LRS-B without a wider consideration of the rest of the Triad...

One thing to consider is that, going forward, we may have significantly less confidence in our legacy, uber-volume and weight optimized physics packages This may bias future designs (in the absence of testing) to heavier, more voluminous but more reliable configurations.

Then there's New START which imposes no limit on the number of nuclear weapons a heavy bomber can carry. It strikes me that bombers are more readily amenable to payload fractionation than the other members of the Triad.

 

[bobbymike]

Probably difficult to really debate the desired nuclear capabilities of LRS-B without a wider consideration of the rest of the Triad...

One thing to consider is that, going forward, we may have significantly less confidence in our legacy, uber-volume and weight optimized physics packages This may bias future designs (in the absence of testing) to heavier, more voluminous but more reliable configurations.

Then there's New START which imposes no limit on the number of nuclear weapons a heavy bomber can carry. It strikes me that bombers are more readily amenable to payload fractionation than the other members of the Triad.

High Yield, volume and weight optimized with incredibly tight tolerances or creating the most bang in the smallest 'physics' package. What you describe as potential future designs equates to the thinking behind RRW or building a highly reliable warhead that did not need testing although apparently the Livermore RRW design was based on early work on the 'Munster' warhead.

As for the thinking about uploadable from the same article..............."The new submarine and the LRS-B are “uploadable” systems that can carry more warheads if strategic requirements change. A senior air force official last week said that the LRS-B would be designed with hardpoints—suggesting that it could be a cruise-missile carrier as well."

 

[sferrin]

We still have that Air Force research program from the mid noughts, there the conceptual bomber was:

20,000lb payload
2,000nm range at Mach 2 cruise

If the LRS-B was sized with a 20,000lb payload, would that be sufficiently large for you, Sferrin? That's about a fourth of the B-1B's internal payload.

Considering an AGM-86C weighs over 4,000lbs you do the math. 20,000lbs is less than one pylon full of cruise missiles on a B-52. 20,000lbs, Mach 2 cruise etc. might be acceptable if it were replacing a B-58. Not for replacing a B-1B and B-52. You just lose way to much flexibility.

 

[dark sidius]

Remember LRS-B is a family of system, not the same of a b-52, type plane, surely smaller than the plane it will replace, in my idea we don't wait for the same thing, LRS-B is something new, to be abble to penetrate the more defensive system on earth, not a single big plane like a B-1 or B-52.

 

[phrenzy]

Depending on its stealth characteristics it might prove to have a decisive capability unique in the triad as a first strike weapon.

Let's not forget that part of the B-2s role was going to be flying undetected into contested airspace and taking out ICBM launch sites including pairing up with long endurance recon aircraft to track and destroy mobile launchers. It was in effect the ultimate first strike weapon (assuming you could get them in the air without alerting satellites or other intelligence channels).

Boomers, which despite their apparent second or subsequent strike role, have been viewed as threatening first strike platforms because if they can sneak up on the coast of an adversary the short launch distance means a missile flight time of 10 minutes or less vs 20-35 for true ICBMs. Although the SLBMs are likely detected by IR satellite sensors, flight confirmation by radar happens a minute or two later than that. 6-8 minutes before you even know what's headed your way and in which direction their headed,. not long to organise a response.

Multiple strike packages made up of a stealthy bombing platform that can get deep into enemy territory undetected and conduct coordinated simultaneous attacks would give warning time of however long it takes for the targeted state to realise their nuke sites are blowing up, essentially zero.

Obviously nobody is expecting LRS-B to be that stealthy but I don't think you can write off the bomber leg of the triad. If it's RCS is low enough to deliver the new stealthy nuclear tipped cruise missiles to such nuclear sites without being detected though, it's a similar situation.

ICBMs and SLBMs are hard to hide once launched.

A fleet of 100 aircraft isn't going to neutralise an arsenal like Russia's but this mission profile might be attractive for north Korea or Iran for example if they were threatening imminent nuclear attack and you didn't want to risk giving them even 10 minutes notice they are under attack to launch the dozen nukes they might potentially have sometime during the flying career of LRS-B's production bomber.


Also, stupid question, but do you think the production aircraft, if it eventuates, will be labeled B-3?

 

[AeroFranz]

The next in sequence is B-4...B-3 being already taken! ;D

 

[phrenzy]

The next in sequence is B-4...B-3 being already taken! ;D

I admit it, you got me

I actually re watched this with my girlfriend the other day, she loves stupid action movies and hates my running technical commentary. I never understood why it needed to be a B-3 though, it didn't have any plot required capabilities the B-2 doesn't have.

Very good though.

 

[LowObservable]

Outstanding movie...

 

[phrenzy]

I did notice that when I watched it the other day. My girlfriend was not as excited as I was about it...I'm such an Anorak.


I would be curious how they are going to designate it though.

 

[bobbymike]

http://aviationweek.com/defense/opinion-how-secrecy-will-kill-next-bomber

From our good friend here at SP.

 

[sferrin]

http://aviationweek.com/defense/opinion-how-secrecy-will-kill-next-bomber

From our good friend here at SP.

Yeah, it was good for a chuckle. As far as I'm concerned they should keep it under wraps at least as much as they did with the F-117.

 

[DrRansom]

If LRS-B is a technological breakthrough (and it may turn out to be a remarkable story, one of decades of quiet persistence leading to the big win), that story can be told as it was 20 years ago, without compromising operations.

What type of big win? Very high stealth with great long range endurance? Or, some sort of high speed stealth?

 

[sferrin]

If LRS-B is a technological breakthrough (and it may turn out to be a remarkable story, one of decades of quiet persistence leading to the big win), that story can be told as it was 20 years ago, without compromising operations.

Yes, AFTER it has been in service a decade or two.

 

[Ian33]

sferrin#
Yeah, it was good for a chuckle. As far as I'm concerned they should keep it under wraps at least as much as they did with the F-117.

I have to hand on heart agree with this if the competition goes the way I am thinking it will go (Smaller, F-111 sized airframes).

 

[flateric]

Careful reading of Wiki timeline on LRS-B is useful starting point to drop out many fancy theories.
Less ambitious than NGB, smaller then B-2, using "proven technology" and off the shelf equipment. Subsonic, VLO.
Should carry one MOP. That gives us idea of weapon bay number and size and maximum weapons load. Can carry ordnance on external pylons and probably external fuel tanks.

 

[TomS]

Wiki claims a payload of 14,000-28,000 lb, but that number isn't actually stated in the article cited as a source.

Just to freak people out further, the comment cited in Wiki about LRS-B and MOP is that the Air Force needs a weapon with the penetrating power of the MOP but about a third the weight so that "it can be carried in an aircraft we can afford to build," according to Deputy CoS Breedlove in 2010. So that works out to a LRS-B payload of about 5 tons, right? ;D


Or not. I wouldn't read that too closely; it could imply that you need LRS-B to carry two of them, or that it needs to fit tactical aircraft as well as bombers, etc.

 

[bobbymike]

http://www.afa.org/mitchellinstitute1/Presentations/

Link to Gen Wilson Commander Global Strike Command on long range strike.

http://www.nationaldefensemagazine.org/blog/Lists/Posts/Post.aspx?ID=1634

 

[LowObservable]

There aren't many MOP targets, or MOPs, and the last time I looked we had a stealth bomber that can carry MOP, and that's in line for an expensive upgrade.


Talk of F-117-like secrecy is moonshine. This isn't a stealthy dustcover over an ingenious assembly of OTS parts.

 

[marauder2048]

an ingenious assembly of OTS parts.

Assuming that's not a totally specious premise. The refrain has been "mature technologies" or "proven technologies." There are plenty of mature/proven technologies that are far from off-the-shelf.

 

[quellish]

There aren't many MOP targets, or MOPs, and the last time I looked we had a stealth bomber that can carry MOP, and that's in line for an expensive upgrade.


Talk of F-117-like secrecy is moonshine. This isn't a stealthy dustcover over an ingenious assembly of OTS parts.

The MOP thing is complicated
MOP is intended to hold a limited number of high value targets at risk with a conventional weapon.


Not everyone is on board with the conventional part. And not everyone thinks the target set is limited to those described by the old SILVER book. Unconventional weapons are smaller, so you can carry more, and hit more aim points. And they can be used to justify a larger strategic force. It would be great if a physically smaller conventional weapon could have similar effects, but that's a problem people have been working on for some time with little to show for it in the public domain.

 

[phrenzy]

Plus if you can get the penetration of the mop with a smaller munition with rocket engines, denser penetrating nose materials or geometry or just dropping it at a faster speed then you would think you could apply those developments to a new mop sized weapon and get even better results.

I'd be very curious to know if they can gague depths and rock types of underground facilties through hyperspectral imaging and designed the mop to be effective against a list of targets or if they just built the biggest penetrator they could that would fit in the B-2 and then are having to use traditional intel methods to figure out what it will be effective against...I suppose if they can't survey such things easily through remote sensing they would maintain some sort of database of the statistics of their high profile potential targets gleaned from other means.

I wonder how much just a handful of a few likely targets (Iranian nuclear sites, DPRK mountain air bases or Russian c&c Bunkers etc.) Is driving the specifications of the LRS-B. whether they work backwards from specific targets to requirements to defeat them to requirements of the actual aircraft.

I'm sure this sort of thing happens when looking at stealth characteristics so that they will be optimised against likely SAM threats but I don't know about potential bombing targets.

 

[marauder2048]

For what it's worth, the analyst consensus during the 3rd quarter earnings calls for the various primes was that LM/Boeing has all but won LRS-B.

 

[flateric]

I.e. if CRS conclusions are true and we deal with pro forma contest with the winner already known and money flow plans hinting to production, not R&D.

 

[sferrin]

For what it's worth, the analyst consensus during the 3rd quarter earnings calls for the various primes was that LM/Boeing has all but won LRS-B.

I wonder if they're going off of anything more than "well Lockheed already won the F-22 and F-35". Personally I'm still thinking it's Northrop Grumman's to lose.