Post - B-21 long range strike capability

[Hydroman]

For air-breathing hypersonics, it lies with materials, propulsion and thermal management for sure and has to get a decent range and be reliable. When I worked on DARPA RASCAL, our F100 propulsion system used MIPCC (Mass Injection Pre-Compressor Cooling) and was rated to M3.5 up to 150K feet altitude with full "sea level" performance from the engines. For a theater strike platform, you could use MIPCC and get very high speed at theater strike altitudes and definitely do some serious supercruising but you have to carry water on-board unfortunately, nothing is free. We used a mix LOX and water via an inlet spray bar system but after test cell propulsion testing completed, could use atomized water alone and performance met predictions. Would be nice to have an VLO/LO, evolved F-111 type for this type of strike mission, we still need a good mix of platform types.

 

[quellish]

Allvin: USAF Sticking to 100 B-21s as It Considers Something New

USAF may not buy more than 100 B-21s as something better may be developed by the time those aircraft are built, CSAF Gen. David Allvin said.

www.airandspaceforces.com

I called this last year and got a ton of shit for it.

I am surprised these statements are getting so much attention.

The Air Force wants to change how they procure aircraft. They want to get new capabilities faster. The "digital century series" concept was an example of this. They wanted to be rolling out new variants or new capabilities every few years. Shorter development cycles, constant testing and development. Long range strike is no exception. The Air Force is well aware that by the time 100 B-21s are constructed they will want something new - wether that is a new program or some variant of the B-21.

 

[Scott Kenny]

There's a room for a non-stealthy cruise-missile carrier, something that's significantly cheaper than the B-21B and has the job of carting cruise missiles from an airbase at a safe range to the launch point and heading home.

That's called the B52.

In all seriousness, everything I've seen says that the B52s can fly till they get about 37k hours. That's the point where they'd have to replace the top skin of the wings, and it's generally not cost-effective to replace those. Replace with new aluminum, not something drilled off a boneyard plane.

The average B52 has about 21k hours right now, at 60 years old (average of 350hr/yr). Should be able to fly about another 45 years averaging 350hrs/yr before they hit 37k hours. 2024+45 is 2069(!).

A realistic design approach will be "Supersonic, large, stealthy, pick any two"(or maybe even any 1.5). Given the likely proliferation of fast missiles plus an acceptably large force of stealthy B-21s, I think a stand-off B-52 successor bomber can afford to be large (B-1 payload, which is actually larger than the B-52) and only moderately stealthy (not to B-21 levels) but relatively slow and economical.

We've got time to work out a new "big dumb object" carrier.

If the USAF does end up going to the semi-stealthy BWB tanker/transport, I suspect that it'll get adopted as a Rapid Dragon carrier for cruise missiles. It's things like ARRW that are big enough to not fit in a weapons bay that raise questions.


================

Personally, for the next USAF bomber I'd like to see something roughly akin to an F23 with a single B2 to B52 sized bomb bay. It'd need much bigger wings to carry the load, and a minimum of F135s if not the Adaptive Flow engines at 45-55klbs thrust. My mental image has it looking a lot like an Su34 Fullback, big 2-seat side by side cockpit and a smooth hump back to hold that monster weapons bay.

Supersonic cruising VLO Intruder/Aardvark, basically, but with 24-30klbs internal bomb capacity.

 

[FighterJock]

That is what I was thinking about the next generation bomber Scott Kenny. I totaly agree with you about the size of the bomber, being the same size or very slightly larger than the Su-34.

 

[Jason Dykstra (Wyvern)]

I wonder if they are re-considering LO theater strike (FB-23 or others as an example) beyond B-21 with high/medium/low altitude capability which could be a supercruiser as well with a reasonable payload?

I was thinking the same thing. NGAD is already going to be a big aircraft, perhaps ordering more of the standard variant, or perhaps, an enlarged, specialised bomber variant, could be seen as a potential B-52 and B-1 replacement as the FB-111 replaced some of the older B-52 variants five decades ago. It could make sense for when a fast response is necessary, like basing out of Europe or SEA/Australia. If I recall, the FB-111G had the range to cross the Atlantic, and the USAF is trying to limit the number of aircraft forward deployed to the Pacific, as they would be easier to target, so a lot of US assets are going to be based stateside, potentially even NGAD.

 

[4decaa]

There's definitely a lot of merit to that, given the sheer quantity that a C-17 can carry and the ubiquitous nature (and rough field capability) of C-130s. Clearly those aircraft would probably be in great demand in their primary roles, but on the other hand even reserving a half dozen C-17s for missile operations would probably give you a sustainable hundred missile a day delivery rate.

I absolutely agree. When I saw the C130 tests, I was impressed, but once I saw the amount of missiles they fit into the C-17 my mind was completely blown. The only limiting factor at that point is range and efficiency - how far you can stretch the C-17's range, and how far you can stretch the missile's range.

Obviously, the raider fulfills a similar role in that it is a strike asset, but the similarities end there with it's lower payload and close-precision strike capability.

also-funny watching the demo videos for the dragon. Spot the real missile!

 

[overscan (PaulMM)]

Moved Northrop ATA related posts to https://www.secretprojects.co.uk/th...venger-ii-its-rivals.1169/page-11#post-672599

 

[Scott Kenny]

That is what I was thinking about the next generation bomber Scott Kenny. I totaly agree with you about the size of the bomber, being the same size or very slightly larger than the Su-34.

I'm pretty sure that a 6ft by 28ft bay will require something more like 100ft long for a supersonic aircraft...

 

[Rhinocrates]

For reference only, LM's and NG's thinking on supersonic manned and unmanned LRSB before the B-21 from the 2000s. I expect that the state of the art will have moved on considerably by the late 2030s but the B-21 does still look a lot like the original B-2 because the laws of physics haven't moved on. LM's unmanned and both of NG's seem to be in the Su-34 or FB-111H class but with more modern needle-like fuselages.

 

[bobbymike]

View: https://m.youtube.com/watch?v=kBmOxSVf_IY

 

[GeorgeA]

DARPA NextRS "Y-plane" hypersonic strike concept:

• 30,000-38,000 lbf TBCC
• Conventional fuel
• Metallic construction

DARPA Eyes Hypersonic Striker As Air Force Studies Long-Term Options | Aviation Week Network

A reusable hypersonic Next-Generation Responsive Strike prototype could be commissioned by the end of the decade.

aviationweek.com

(May be paywalled.)

 

[FighterJock]

Pity the full article is behind a paywall GeorgeA. That is one of the things I hate about the Internet.

 

[dark sidius]

Pity the full article is behind a paywall GeorgeA. That is one of the things I hate about the Internet.

May be the reason why no more than 100 B-21, I think it will finish with 60 B-21 and a new hypersonic striker program , technology start to be mature I think...

 

[DrRansom]

The problem with B-52 and B-21 is that - being based CONUS - they'll have no ability to respond to time-sensitive targets in the Pacific Theater. Also, their sortie rate would be so low as to make additional investment very questionable.

If China sends a fleet from one base (which'll have an air defense bastion) to another landing site (with it's own air defense bastion), the fleet will be exposed for some period of time, maybe 5-15 hours. That time is too short for any bomber strike coming out of CONUS - even if equipped with hypersonic missiles.

A FB-111 class aircraft designed for semi-STOL operations out of Japan would be one of the few designs that could maintain a decently high sortie rate and attack reasonably often. It would have to trade VLO for basing flexibility and size and carry most of the weapons externally - especially large cruise missiles.

Either the USAF has to give up on the idea of secure bases and find a way to fight in theater - or its budget should be cut and given to a service that's willing to take risks.

 

[4decaa]

The problem with B-52 and B-21 is that - being based CONUS - they'll have no ability to respond to time-sensitive targets in the Pacific Theater. Also, their sortie rate would be so low as to make additional investment very questionable.

If China sends a fleet from one base (which'll have an air defense bastion) to another landing site (with it's own air defense bastion), the fleet will be exposed for some period of time, maybe 5-15 hours. That time is too short for any bomber strike coming out of CONUS - even if equipped with hypersonic missiles.

A FB-111 class aircraft designed for semi-STOL operations out of Japan would be one of the few designs that could maintain a decently high sortie rate and attack reasonably often. It would have to trade VLO for basing flexibility and size and carry most of the weapons externally - especially large cruise missiles.

Either the USAF has to give up on the idea of secure bases and find a way to fight in theater - or its budget should be cut and given to a service that's willing to take risks.

What are you reading that is saying these planes will only be based in continental airbases?

The US has already had to sustain B-2 operations (and maintenance, which is largely more difficult than that required for the 21') in Diego Garcia and Guam. What makes you think that B-21's won't be operated in American air bases near China (Japan, Australia, Guam, Diego Garcia)?

 

[Josh_TN]

The problem with B-52 and B-21 is that - being based CONUS - they'll have no ability to respond to time-sensitive targets in the Pacific Theater. Also, their sortie rate would be so low as to make additional investment very questionable.

If China sends a fleet from one base (which'll have an air defense bastion) to another landing site (with it's own air defense bastion), the fleet will be exposed for some period of time, maybe 5-15 hours. That time is too short for any bomber strike coming out of CONUS - even if equipped with hypersonic missiles.

A FB-111 class aircraft designed for semi-STOL operations out of Japan would be one of the few designs that could maintain a decently high sortie rate and attack reasonably often. It would have to trade VLO for basing flexibility and size and carry most of the weapons externally - especially large cruise missiles.

Either the USAF has to give up on the idea of secure bases and find a way to fight in theater - or its budget should be cut and given to a service that's willing to take risks.

Landing operations do not end at the 15 hour mark. Supporting an invasion in Taiwan would take a fairly vast amount of resupply and follow on forces, assuming there was any resistance. I think the USAF is going to need an in theater attack capability as well, but it is going to have to be more expendable than an F-111 sized or priced platform. I think ultimately a UAV will fulfill this role.

 

[Josh_TN]

What are you reading that is saying these planes will only be based in continental airbases?

The US has already had to sustain B-2 operations (and maintenance, which is largely more difficult than that required for the 21') in Diego Garcia and Guam. What makes you think that B-21's won't be operated in American air bases near China (Japan, Australia, Guam, Diego Garcia)?

A lot of USAF studies and press releases seem to imply that the bomber force will not be forward based, though it might be forward refueled and rearmed for a couple of strikes before returning to a hub base in the CONUS. Basing within ballistic missile range will be problematic, though Australia would be out of range of most anything smaller than an ICBM.

 

[DrRansom]

Landing operations do not end at the 15 hour mark. Supporting an invasion in Taiwan would take a fairly vast amount of resupply and follow on forces, assuming there was any resistance. I think the USAF is going to need an in theater attack capability as well, but it is going to have to be more expendable than an F-111 sized or priced platform. I think ultimately a UAV will fulfill this role.

Once China gets an air defense network emplaced - the ships near the beach may be especially well defended. Based on experience, defeating modern AD systems takes weeks to months. It may prove (counter to historical example) easier to hit ships at sea than when covered by land-based area defenses.

Any UAV will be just as expensive (or more so) than a manned aircraft. Range and payload dictates aircraft size. It will be a F-111 sized system because the payloads (stand-off cruise missiles) and ranges (1000+nm) demand so. The aircraft won't be really expendable, because the size makes it so.

Lastly, there's just a really bad precedent to basing the entire bomber force out of the US. The entire USAF will be reduced to 100 B-21s and some 50 B-52s, less those held in nuclear reserve. That's (to be generous) 50 sorties a day? Simply wildly inadequate for a world war.

 

[Josh_TN]

50 sorties/day would still be >= 1000 PGMs per day. If the primary target set is the amphibious ships themselves (predominantly large vehicle ferries), then the target set is probably as few as a hundred platforms. It seems manageable.

 

[Scott Kenny]

Once China gets an air defense network emplaced - the ships near the beach may be especially well defended. Based on experience, defeating modern AD systems takes weeks to months. It may prove (counter to historical example) easier to hit ships at sea than when covered by land-based area defenses.

Any UAV will be just as expensive (or more so) than a manned aircraft. Range and payload dictates aircraft size. It will be a F-111 sized system because the payloads (stand-off cruise missiles) and ranges (1000+nm) demand so. The aircraft won't be really expendable, because the size makes it so.

The payloads don't need to be LRASMs.

For example, in the most recent China/Taiwan wargame, one of the CCAs available was a long range 2x LRASM carrier. The people playing the game didn't use it. If the UAV is LO enough to get within ~100nmi of the ships, just load it with JDAM-ERs.

 

[4decaa]

The payloads don't need to be LRASMs.

For example, in the most recent China/Taiwan wargame, one of the CCAs available was a long range 2x LRASM carrier. The people playing the game didn't use it. If the UAV is LO enough to get within ~100nmi of the ships, just load it with JDAM-ERs.

Mind linking the war game? not skeptical or anything-just curious about how it played out.

For the glide JDAM, wouldn’t that be far easier to detect than a LRASM? additionally. it would need some sort of satellite ISR or other recon to target moving ships, and cannot make any final phase evasion maneuvers like the LRASM.

 

[Josh_TN]

Alternative payloads might be SDB or in the future SiAW. Were a dedicated rack system developed for the B-21 around a hundred GBU-53 might be carried (a study determined a B-2 could carry between “192-216”). I’d think twenty SiAW would be possible. The former would not move fast or hit hard, but there’s a hundred of them. The later would be harder to intercept.

For the B-52 I would expect HACM to have an anti ship mode, if not initially then in a later version (Blk 2?).

 

[Scott Kenny]

Mind linking the war game? not skeptical or anything-just curious about how it played out.

Sure!

Report is titled "The Need for CCAs", a PDF of the powerpoint slides is "CCA Wargame Rollout"

For the glide JDAM, wouldn’t that be far easier to detect than a LRASM? additionally. it would need some sort of satellite ISR or other recon to target moving ships, and cannot make any final phase evasion maneuvers like the LRASM.

Sure, it probably would be easier to detect, but it's a small target that is hard to damage. IIRC, the current crop of JDAMs can have their target updated in flight.

 

[4decaa]

Report is titled "The Need for CCAs", a PDF of the powerpoint slides is "CCA Wargame Rollout"



Sure, it probably would be easier to detect, but it's a small target that is hard to damage. IIRC, the current crop of JDAMs can have their target updated in flight.

Thanks for sending these over.

Pretty interesting to spot the 'slot' the Raider is going to fill, perhaps generals saw how Russia seemed like it would be far too busy to help the Chinese in the Pacific in any significant capacity, and decided to stick with the 100 B-21's. Cheers!

Alternative payloads might be SDB or in the future SiAW. Were a dedicated rack system developed for the B-21 around a hundred GBU-53 might be carried (a study determined a B-2 could carry between “192-216”). I’d think twenty SiAW would be possible. The former would not move fast or hit hard, but there’s a hundred of them. The later would be harder to intercept.

For the B-52 I would expect HACM to have an anti ship mode, if not initially then in a later version (Blk 2?).

Josh, I did not know that the B-2 was able to carry that many munitions. That many Stormbreakers would be extremely effective over a possible invasion of Taiwan, allowing a few Raiders to target a massive spread of smaller targets (troops, vehicles, mobile SAMs, etc). While likely unable to generate hard kills, a hit from a Stormbreaker would likely to disable a tank for some amount of time, or at least significantly degrade it's fighting capability.

 

[Josh_TN]

Sure, it probably would be easier to detect, but it's a small target that is hard to damage. IIRC, the current crop of JDAMs can have their target updated in flight.

There are already anti ship guidance kits for JDAM - Quicksink. The bigger problem with glide weapons in a naval context is that their performance envelope puts them in range of every defensive weapon type for an extended period of time. Even main gun fire would be perfectly effective.

 

[Josh_TN]

Josh, I did not know that the B-2 was able to carry that many munitions. That many Stormbreakers would be extremely effective over a possible invasion of Taiwan, allowing a few Raiders to target a massive spread of smaller targets (troops, vehicles, mobile SAMs, etc). While likely unable to generate hard kills, a hit from a Stormbreaker would likely to disable a tank for some amount of time, or at least significantly degrade it's fighting capability.

Clarification: B-2 is not known to integrated with either version of SDB. This was a study paper from a decade or two ago. SDB I integration was dropped because it was felt there was little advantage over 500 lb JDAM and SDB II was never integrated so far as is known. It may still be happening; integrations with the threshold plan (F-15) took longer than expected. My personal guess however is that this will not occur given the difficulty in updating the B-2s older, non open architecture avionics and the coming IOC of B-21. But I think it is fair to expect the B-21 to be integrated with SDB 1/2 and to have a large capacity for them. Being able to carry large numbers of inexpensive munitions was one of the justifications for adopting a penetration bomber vice a less ambitious cruise missile carrier.

A hit from Stormbreaker would destroy or disable any vehicle; even assuming its HEAT jet didn’t penetrate, the warhead is probably in the same class as a hit from 203mm howitzer round (less shrapnel but more bang).

 

[SK2]

Clarification: B-2 is not known to integrated with either version of SDB. This was a study paper from a decade or two ago. SDB I integration was dropped because it was felt there was little advantage over 500 lb JDAM and SDB II was never integrated so far as is known. It may still be happening; integrations with the threshold plan (F-15) took longer than expected. My personal guess however is that this will not occur given the difficulty in updating the B-2s older, non open architecture avionics and the coming IOC of B-21. But I think it is fair to expect the B-21 to be integrated with SDB 1/2 and to have a large capacity for them. Being able to carry large numbers of inexpensive munitions was one of the justifications for adopting a penetration bomber vice a less ambitious cruise missile carrier.

Speaking of B-2 with SDB, Air Force Monthly (or Air International?) in the late 90s has one critical comic (?) with a woman talking on phone with her B-2 pilot husband "Honey, can you drop one more line of SDB? I would like to plant more peas!" with a B-2 flyover dropping tens/hundreds of SDB and creating small holes...the editor seems quite critical with SDB in the early days

 

[Scott Kenny]

There are already anti ship guidance kits for JDAM - Quicksink. The bigger problem with glide weapons in a naval context is that their performance envelope puts them in range of every defensive weapon type for an extended period of time. Even main gun fire would be perfectly effective.

You're trying to damage a 3-4" thick steel bomb casing with fragments? I don't think that's going to work. From head on, the tail fins are mostly shielded behind the bomb casing.

 

[Josh_TN]

You're trying to damage a 3-4" thick steel bomb casing with fragments? I don't think that's going to work. From head on, the tail fins are mostly shielded behind the bomb casing.

It will be perfectly effective against the guidance system and the control surfaces. I am pretty sure a WWII IJN gunner would be surprised if a SBD managed to deliver its bomb after taking a close flak hit, and a glide bomb is basically the worst of torpedo bombers and dive bombers mixed together. Do you think 5" fire would be ineffective? Or 100mm or 76mm?

 

[Scott Kenny]

It will be perfectly effective against the guidance system and the control surfaces. I am pretty sure a WWII IJN gunner would be surprised if a SBD managed to deliver its bomb after taking a close flak hit, and a glide bomb is basically the worst of torpedo bombers and dive bombers mixed together. Do you think 5" fire would be ineffective? Or 100mm or 76mm?

You'd actively want the proximity fuze blowing up late and off center. If it blows up early, all those fragments ping off 4" thick steel bomb casing and don't do anything but scratch the paint or chip the fire retardant coating off if it's a Navy bomb. If it blows up on center, the bomb casing deflects the fragments away from the tail surfaces.

Most modern proximity fuzes try to pop early, especially the P3 types like AHEAD, and are used to chewing up Tomahawks or SLAM-ERs. Which are all built like an airplane with ~1mm thick skin at most.

 

[Josh_TN]

If the bomb is wearing a wing kit, tearing that off asymmetrically likely is unrecoverable.

 

[Scott Kenny]

I wonder if they are re-considering LO theater strike (FB-23 or others as an example) beyond B-21 with high/medium/low altitude capability which could be a supercruiser as well with a reasonable payload?

Well, the Strike Eagles are going to be completely out of service life starting in about 2038. So they're going to have to get going on a replacement pretty soon to keep those squadrons going. 10 years to get to first flight, another 4 years to IOC. Oh, crap that's 2024, basically needs to happen this year, and/or hope for smooth development and early flights...

That is what I was thinking about the next generation bomber Scott Kenny. I totaly agree with you about the size of the bomber, being the same size or very slightly larger than the Su-34.

Nah, it's going to be bigger than that. My comparison to the Su34 was strictly for visuals, since the bomb bay I'm expecting it to use is 28ft long all by itself!

Some further thoughts about desired abilities

24k-30klb payload capacity, bomb bay is 6ft wide and 28ft long (as mentioned before), so roughly twice the length of the YF23 bay and far deeper. Probable range requirement with full bombload is 2000nmi, which is F15E ferry range. We can make an argument for a 3000nmi range, but that's probably the maximum. Being able to tank about 500nmi out from the Chinese coast and still reach targets well inland is required.

I'm going to guesstimate for a plane 2x the MTOW of the YF23, so ~125,000lbs MTOW and an empty weight of ~58,000lbs. 24klbs of that is bombs, and I'm also assuming a couple of BVRAAMs and a couple of AARGM-ERs in separate bays in the chines for good measure, call it 27klbs total weapons load. 2^(1/3) is 1.25, so we're talking about a plane some 85ft long, 55ft wingspan, and ~18ft tall, with a wing area of ~1430sqft (1.25^2=1.58, and wiki lists the YF23 with 900sqft wing area). That gives a wing loading of ~87.4lb/sqft at MTOW.

58,000lbs empty weight plus 27,000lbs of weapons makes 85,000lbs, so potentially 40,000lbs of fuel onboard(!). That should give you some pretty good range on a pair of F135s. Still going to handle like a pig till you dump some of the bombs out, you'll have a thrust:weight ratio of ~0.7 at 50% fuel with full bomb load.

On the other hand, it'd be a pretty sporty airplane when unloaded. Once the bombs are out, the T:W gets up to 1.06 at 50% fuel!

If the bomb is wearing a wing kit, tearing that off asymmetrically likely is unrecoverable.

Depends on how much of the wing is lost and how much authority the tail fins have, but at the very least the extra drag will compromise range. So partial agreement there.

 

[FighterJock]

That is what I was thinking Scott Kenny.