Northrop Grumman B-21 Raider (LRS-B)

[rooster]

It makes perfect sense to retire one of your three existing bomber types as the new platform comes online. It appears the B-1 fleet would be first, as the fleet is worn out and hard to maintain already. There's a lot of savings to be had by retiring an entire class of aircraft.

And a lot of capability to be lost. The B-1B is the LAST of the three I'd want to retire, especially now that they're (supposedly) reactivating external hard points. If the B-21 is duplicating B-2 capability then retire the B-2. Both the B-1B and B-52 have capabilities the B-21 or B-2 do not.

The bones are worn out. They weren't meant to be in service this long. The rockwell engineers freaked out in the 80s when the usaf was doing touch and goes with them because of the wear and tear on the metal. It was afterall a high altitude aircraft that the Regan administration repurposed into a low altitude interim bomber because it was the fastest and cheapest way to add capability to the usaf for the 80s buildup to bankrupt Russia. A lot of that 80s buildup was done in haste and almost smoke and mirrors with pulling ships out of mothball just to add numbers to the navy and rushing the peacekeeper into service with parts from radioshack. The bones were meant to spend their lives sitting on alert, not serving as a replacement for the aardvark and fighting in decades long wars. Maybe if they had developed a b1c in the 90s purpose built for how they actually were going to use them conventionally it might make sense to keep it around. The readiness rate is very low for the 50 or so still in service. I never understood not putting it back into production after congress gutted the b2 program... They needed something and went with nothing.

 

[mkellytx]

And a lot of capability to be lost. The B-1B is the LAST of the three I'd want to retire, especially now that they're (supposedly) reactivating external hard points. If the B-21 is duplicating B-2 capability then retire the B-2. Both the B-1B and B-52 have capabilities the B-21 or B-2 do not.

Why the attachment to the B-1? Just what exactly is lost if the 34th BS & 37th BS convert from 12 PAA B-1's to 12-16 PAA B-21's, followed by the 9th BS & 28th BS swapping their 12 for 12-16? What exactly is better with a bomber fleet of 20 B-21's, 45 B-1's & 76 B-52's versus 20 B-2's, 45 B-21's & 76 B-52's? What capability does the latter lack that is so detrimental?

 

[sferrin]

And a lot of capability to be lost. The B-1B is the LAST of the three I'd want to retire, especially now that they're (supposedly) reactivating external hard points. If the B-21 is duplicating B-2 capability then retire the B-2. Both the B-1B and B-52 have capabilities the B-21 or B-2 do not.

Why the attachment to the B-1? Just what exactly is lost if the 34th BS & 37th BS convert from 12 PAA B-1's to 12-16 PAA B-21's, followed by the 9th BS & 28th BS swapping their 12 for 12-16? What exactly is better with a bomber fleet of 20 B-21's, 45 B-1's & 76 B-52's versus 20 B-2's, 45 B-21's & 76 B-52's? What capability does the latter lack that is so detrimental?

There's nothing guaranteeing it'll even be a one-for-one replacement. If the past is any indicator it will almost certainly be less. And how many B-21s does it take to equal the payload of one B-1B? They're talking about reactivating the external hardpoints on the B-1B (even if they don't the potential is still there). Will that option be available on the B-21? (That's a rhetorical question. Of course it won't be.) Will the B-21 be able to perform ALL of the missions currently performed by the B-1B?

 

[Bhurki]

And how many B-21s does it take to equal the payload of one B-1B

Considering defended airspace, 0.

Considering non defended airspace, B52 gets the job done way cheaper.

 

[mkellytx]

There's nothing guaranteeing it'll even be a one-for-one replacement. If the past is any indicator it will almost certainly be less.

There never is, however, unlike the B-2 program the B-21 appears to be on cost and on (COVID) schedule. Very much unlike the B-2 the SECAF upped the number of B-21's that should be procured from 100 to 150+. Continue to be a specific if you wish, the trend here is in the favorable direction.

And how many B-21s does it take to equal the payload of one B-1B? They're talking about reactivating the external hardpoints on the B-1B (even if they don't the potential is still there). Will that option be available on the B-21? (That's a rhetorical question. Of course it won't be.)

External, other than TGP is way overblown, unless of course you want an aircraft that can't fly higher than 20,000 ft. with any meaningful fuel+bomb load, then again the external load is rather mute since the airframe is sunsetting and not likely to spend the money to

Will the B-21 be able to perform ALL of the missions currently performed by the B-1B?

Since useless dirt seems to be over the proper question is the converse, will the B-1 be able to perform all of the missions performed by the B-21. Honestly, low risk, a BUFF with a TGP can do everything a Bone can except fly supersonic. High risk, very little the B-21 can do can the B-1 do...

 

[bennyp]

How significant is the B-1's M1.25 capability in reality?

 

[kaiserd]

How significant is the B-1's M1.25 capability in reality?

Not very. Though even if not really using supersonic capability the B-1B is still that much faster than a B-52 which had and has it uses in some scenarios (e.g. a loitering bomber responding to a specific request for close air support/ target of opportunity). However this advantage is limited and probably more than balanced out by other factors even just for those scenarios (e.g. availability rate impacting if there is a loitering bomber there at all that is able to respond to such a request, etc.).

 

[Hydroman]

To my knowledge and from working on the B-2 program, the aircraft does not fly missions at low altitude to my knowledge, I left the program in 1997. We flight tested low altitude, terrain following but the aircraft is too slow for the low altitude mission. Tornado, F-111, B-1, all fast-movers but the B-2, not so much. However, the B-2 is quiet at low altitude when at stable speed and at a stable throttle condition. The high to medium altitude mission for the B-21 is just fine.

 

[mkellytx]

How significant is the B-1's M1.25 capability in reality?

Usually, not much. However, there were some niche situations where it came in handy, namely in the early stages of OEF/OIF. Before in country fighter bases were established, the Bones could fly from Thumrait or the Al Udeid into Afghanistan or Iraq without refueling, establish the orbit and get anywhere in the country within a specific response time. That saved the Bones from retirement in 2004, with peer competition and now that we're out of both it's less important.

 

[thefrecklepuny]

It makes perfect sense to retire one of your three existing bomber types as the new platform comes online. It appears the B-1 fleet would be first, as the fleet is worn out and hard to maintain already. There's a lot of savings to be had by retiring an entire class of aircraft.

And a lot of capability to be lost. The B-1B is the LAST of the three I'd want to retire, especially now that they're (supposedly) reactivating external hard points. If the B-21 is duplicating B-2 capability then retire the B-2. Both the B-1B and B-52 have capabilities the B-21 or B-2 do not.

The bones are worn out. They weren't meant to be in service this long. The rockwell engineers freaked out in the 80s when the usaf was doing touch and goes with them because of the wear and tear on the metal. It was afterall a high altitude aircraft that the Regan administration repurposed into a low altitude interim bomber because it was the fastest and cheapest way to add capability to the usaf for the 80s buildup to bankrupt Russia. A lot of that 80s buildup was done in haste and almost smoke and mirrors with pulling ships out of mothball just to add numbers to the navy and rushing the peacekeeper into service with parts from radioshack. The bones were meant to spend their lives sitting on alert, not serving as a replacement for the aardvark and fighting in decades long wars. Maybe if they had developed a b1c in the 90s purpose built for how they actually were going to use them conventionally it might make sense to keep it around. The readiness rate is very low for the 50 or so still in service. I never understood not putting it back into production after congress gutted the b2 program... They needed something and went with nothing.

I read some time ago that Rockwell proposed 48 stealthier B-1C's as a cheaper alternative to the B-2.

 

[rooster]

It makes perfect sense to retire one of your three existing bomber types as the new platform comes online. It appears the B-1 fleet would be first, as the fleet is worn out and hard to maintain already. There's a lot of savings to be had by retiring an entire class of aircraft.

And a lot of capability to be lost. The B-1B is the LAST of the three I'd want to retire, especially now that they're (supposedly) reactivating external hard points. If the B-21 is duplicating B-2 capability then retire the B-2. Both the B-1B and B-52 have capabilities the B-21 or B-2 do not.

The bones are worn out. They weren't meant to be in service this long. The rockwell engineers freaked out in the 80s when the usaf was doing touch and goes with them because of the wear and tear on the metal. It was afterall a high altitude aircraft that the Regan administration repurposed into a low altitude interim bomber because it was the fastest and cheapest way to add capability to the usaf for the 80s buildup to bankrupt Russia. A lot of that 80s buildup was done in haste and almost smoke and mirrors with pulling ships out of mothball just to add numbers to the navy and rushing the peacekeeper into service with parts from radioshack. The bones were meant to spend their lives sitting on alert, not serving as a replacement for the aardvark and fighting in decades long wars. Maybe if they had developed a b1c in the 90s purpose built for how they actually were going to use them conventionally it might make sense to keep it around. The readiness rate is very low for the 50 or so still in service. I never understood not putting it back into production after congress gutted the b2 program... They needed something and went with nothing.

I read some time ago that Rockwell proposed 48 stealthier B-1C's as a cheaper alternative to the B-2.

I heard something about an advanced b1 proposal in the late 80s from a usaf retired brig gen I knew about 20 years ago but by then usaf had all its chips on an all stealth air force come high or hell water.... We see how that turned out.

 

[jsport]

View: https://mitchellinstituteaerospaceadvantage.podbean.com/e/episode-21-the-merge-national-security-space-and-the-future-of-air-to-ground-munitions/?utm_source=Sailthru&utm_medium=email&utm_campaign=EBB%2005.17.21&utm_term=Editorial%20-%20Military%20-%20Early%20Bird%20Brief

 

[NeilChapman]

How significant is the B-1's M1.25 capability in reality?

I believe Ive read that they typically run subsonic. It would be interesting to know the typical cruise speed difference between the two.

The 52s already have a significant range/loiter advantage and with new engines that will only increase will it not? 20-30%

Isn't that award due soon?

 

[mkellytx]

I believe Ive read that they typically run subsonic. It would be interesting to know the typical cruise speed difference between the two.

Pretty much, wing sweep determines a lot, anything below 25 degrees is limited to 0.8 M, 45-55 degrees 1.0 M. It's highly thrust/weight/sweep dependent on if you want to make a level turn above 20 kft. It's been quite a while since I've looked at the performance sup, so don't remember the optimums. The bay doors are limited to 0.94 M though.

The 52s already have a significant range/loiter advantage and with new engines that will only increase will it not? 20-30%

RFP wants 30% efficiency, 40% range/loiter.

Isn't that award due soon?

Bids were due last year so hopefully by the end of the fiscal year.

 

[pesholito]

Martial Arts

Memo to bad guys: Wanna know what U.S. warplanes you’ll tangle with in the future? Visit an aerospace model shop.

www.airspacemag.com

The 6th picture.

https://thumbs-prod.si-cdn.com/GkYDj3A_pbhdtvyf8tXWdEciTKI=/fit-in/1072x0/https://public-media.si-cdn.com/filer/Future_Models_Gal_F_SEP09.jpg

 

[flateric]

Martial Arts

Memo to bad guys: Wanna know what U.S. warplanes you’ll tangle with in the future? Visit an aerospace model shop.

www.airspacemag.com

The 6th picture.

https://thumbs-prod.si-cdn.com/GkYDj3A_pbhdtvyf8tXWdEciTKI=/fit-in/1072x0/https://public-media.si-cdn.com/filer/Future_Models_Gal_F_SEP09.jpg

This is 15 years old NG NGB concept.

 

[Josh_TN]

It seems very likely that B-21, PAK-DA, and H-20 all adopt the same geometry of the original B-2 before the 'saw tooth' change to the design (this was driven by USAF requirements to allow for low altitude penetration in case stealth was compromised). That shape presents the least number of vulnerable angles (four) and works well for bomber sizes. The 'cranked kite' shape is apparently more flexible to scale to smaller aircraft sizes, at the cost of introducing additional angles of concern.

 

[Dreamfighter]

Question...
When a certain NASA 2016 SBIR (Small Business Innovation Research) Phase I solicitation literally mentions:

"NL-DFS will be marketed towards flight test applications on a wide class of aerospace vehicles such as: (a) USAF's F-22 and F-35 aircrafts at Edwards AFB; (b) UASF's long range supersonic strike bomber as well as stealth UAV/UCAV; (c) DARPA's advanced design concept; (d) Boeing 787; and (e) future executive jet designs of Cessna, Raytheon, etc. The proposed NL-DFS can also be applied to validate health management strategies specifically designed for aircraft designs with prominent aeroelastic characteristics."

SBIR-16-1-A1.01-8122 | Abstract - Dynamic Flight Simulation Utilizing High Fidelity CFD-Based Nonlinear Reduced Order Model

Would the used term "long range supersonic strike bomber" in that solicitation then;
a) just be wrong, and it should have been 'long range strike bomber' ?
b) refer to the B-1B Lancer ?
c) refer to a bomber from the NGB program, preceding LRS-B (B-21)?
d) refer to some LRSA or LRS-A bomber program, as mentioned a few times in the 'US Next generation bomber studies'-thread ?
e) possibly refer to the LRS-B (B-21) ?!
f) refer to a future bomber for after LRS-B (B-21) ?


Edit: link added

 

[Grey Havoc]

d) refer to some LRSA or LRS-A bomber program, as mentioned a few times in the 'US Next generation bomber studies'-thread ?

Indeed, the B-21 was to be a supersonic bomber, back before the rather ill-advised decision to switch to a sub-sonic design. At least one testbed was even reportedly flown by NG.

 

[Dreamfighter]

d) refer to some LRSA or LRS-A bomber program, as mentioned a few times in the 'US Next generation bomber studies'-thread ?

Indeed, the B-21 was to be a supersonic bomber, back before the rather ill-advised decision to switch to a sub-sonic design. At least one testbed was even reportedly flown by NG.

Thanks, I was living with the idea that any supersonic requirement was dropped before contract-award to NG in fall 2015, not after.
Interesting to know that there may be a side-tracked/cancelled supersonic version of B-21 (not NGB) around.

 

[flateric]

Indeed, the B-21 was to be a supersonic bomber, back before the rather ill-advised decision to switch to a sub-sonic design.

Was it?

 

[Rhinocrates]

Indeed, the B-21 was to be a supersonic bomber, back before the rather ill-advised decision to switch to a sub-sonic design.

Was it?

Scraping the bottom of the barrel of my memory, an early plan was to have an 'interim' bomber for 2018, followed by a '2035' bomber with supercruise, for which we've seen concepts from Lockheed Martin and Northrop Grumman. However, both were cancelled and the B-21 survives, roughly based on the 2018 interim design requirement.

 

[Grey Havoc]

Was it?

Yes. We have still yet to see the design in the flesh, but the indications to date are troubling. (And that is leaving aside the debate whether a non-expendable small stealthy subsonic bomber is at all viable in the present day.) Smaller bomb load (ironic in light of the original 'large and flexible payload bay' requirement), but apparently with a lesser unrefueled range than, the B-2 it is supposed to replace (even more ironic). Classifying it as a nuclear capable medium bomber would be rather stretching things, especially given that its nuclear qualification is now once again supposed to only take place at least two years after it finally reaches IOC.

One of the justifications for the switch to a subsonic design was that, with the simultaneous addition of the optionally manned required requirement (it had been previously studied as part of the NGB but the proponents for such an option had been having difficulty making a case for it to be added, especially with ongoing problems in the area of UAVs) to the program, it would be much easier and cheaper to expend an unmanned subsonic bomber than a unmanned supersonic one. Another string to this was that supposedly the B-21's unrefueled range would be greatly increased in unmanned mode compared to manned operations. And in cases where that was not enough, well, the USAF was confident that its large network of available airbases and its healthy (cue loud laughter) tanker fleet would, together with the much larger numbers of B-21 bombers they would now be able to buy, would be easily able to cover any contingency. However, even before Obama had left office, the optionally manned capability had been shelved (officially 'delayed' for budgetary reasons, which one could consider a darkly amusing note). Added to this the various policy, procurement, and geopolitical disasters of the day along with those that have followed in the time since, and all those airily parroted justifications have either vaporised in the cold daylight of reality, or else look shakier than a drunk trapeze artist on the high wire act without a safety net.

In the present day it now seems rather unlikely that the B-21 fleet will ever have anywhere near the numbers and deployment locations required, in the light of the type's dire lack of speed, range, and payload, to be able to respond to a sudden overseas emergency in anything resembling a reasonable timeframe. And that is before we get to things like mission systems, available payload & associated delivery options. All of course assuming that the B-21 is not abruptly cancelled in the near future.

And all that is not even touching on fiascoes like the abortive planned switch to biofuel (technically the biofuel program wasn't a B-21 specific requirement).

 

[shin_getter]

If the US could not get B-21 class aircraft into the conflict, it may very well be a unwinnerable conflict (or at least, not one that could be won without wwii tier mobilization) to begin with. To deal with the massive tactical disadvantage this situation suggests with technology is not unlike trying to build a fleet of amerikabomber to win the war.

 

[kaiserd]

Was it?

Yes. We have still yet to see the design in the flesh, but the indications to date are troubling. (And that is leaving aside the debate whether a non-expendable small stealthy subsonic bomber is at all viable in the present day.) Smaller bomb load (ironic in light of the original 'large and flexible payload bay' requirement), but apparently with a lesser unrefueled range than, the B-2 it is supposed to replace (even more ironic). Classifying it as a nuclear capable medium bomber would be rather stretching things, especially given that its nuclear qualification is now once again supposed to only take place at least two years after it finally reaches IOC.

One of the justifications for the switch to a subsonic design was that, with the simultaneous addition of the optionally manned required requirement (it had been previously studied as part of the NGB but the proponents for such an option had been having difficulty making a case for it to be added, especially with ongoing problems in the area of UAVs) to the program, it would be much easier and cheaper to expend an unmanned subsonic bomber than a unmanned supersonic one. Another string to this was that supposedly the B-21's refueled range would be greatly increased in unmanned mode compared to manned operations. And in cases where that was not enough, well, the USAF was confident that its large network of available airbases and its healthy (cue loud laughter) tanker fleet would, together with the much larger numbers of B-21 bombers they would now be able to buy, would be easily able to cover any contingency. However, even before Obama had left office, the optionally manned capability had been shelved (officially 'delayed' for budgetary reasons, which one could consider a darkly amusing note). Added to this the various policy, procurement, and geopolitical disasters of the day along with those that have followed in the time since, and all those airily parroted justifications have either vaporised in the cold daylight of reality, or else look shakier than a drunk trapeze artist on the high wire act without a safety net.

In the present day it now seems rather unlikely that the B-21 fleet will ever have anywhere near the numbers and deployment locations required, in the light of the type's dire lack of speed, range, and payload, to be able to respond to a sudden overseas emergency in anything resembling a reasonable timeframe. And that is before we get to things like mission systems, available payload & associated delivery options. All of course assuming that the B-21 is not abruptly cancelled in the near future.

And all that is not even touching on fiascoes like the abortive planned switch to biofuel (technically the biofuel program wasn't a B-21 specific requirement).

Is there any actual evidence or any attributable sources for any of those statements of “fact”?
Any by any chance any of that has any basis in fact and/ or reality why are the Russians and the Chinese airforces moving ahead with their own equivalents (sub-sonic stealthy flying wing bombers)?

 

[Hydroman]

Don't want to be rude but I agree with kaiserd, speculation is great fun but not unless you are cleared into the/a program then these are just speculation posts. China and Russia are moving forward with their so-called "stealth" bombers probably because of the USA's success with various programs plus the USA has in my opinion quite a "decades" lead with this technology which is real and dates back to the 1940's in regards to larger airframes. Russia dances to their own drum, China is nothing more than a copy-cat of other's tech, period. I will be impressed when China develops their own some day. Evidently, flying wings are the current benchmark for LO or others would not be developing their own aircraft based on wing-type designs, NGC shaping rules the day again.

 

[shin_getter]

The main thing that the post is that not about poor optimization given constraints: it is "we need larger fleet of higher performing aircraft" (in ALL dimensions!) which translate to "we need much much larger defense spending" which is not something engineer or fighting men can decide.

If one thinks like a self interested tax payer, the purpose of the military must serve the self and not the notion of global empire control except when the it support the former. If a wealthy opponent is willing to pay extreme costs for someone we currently own but not essential, the realpolitik line of thinking is how to extract the most value in a sale, not how to desperately hold onto it. Defense spending is about preventing the opponent from cheating while the transaction is sorted out.

 

[Bhurki]

the realpolitik line of thinking is how to extract the most value in a sale, not how to desperately hold onto it.

Sometimes, 'holding' is the only option you got.
If you stop to desperately 'hold' it to status quo, the effective weight of the opposition increases multifold like a zero sum game but losses and gains are compounded over every trade, effectively making every next step much harder to execute.

The reason people are fretting over Taiwan isn't as much to do with the island itself but contemplating how hard would it be to maintain a force posture in Asia against China once it falls.

 

[shin_getter]

the realpolitik line of thinking is how to extract the most value in a sale, not how to desperately hold onto it.

The reason people are fretting over Taiwan isn't as much to do with the island itself but contemplating how hard would it be to maintain a force posture in Asia against China once it falls.

Basically sell Japan, South Korea and Australia some hypersonic delivery vehicles and call it a day.

Sure this means little influence in the area afterwards, but it is not like that sort of thing helped the average tax payer much. (unless you buy into the whole mega currency manipulation concept)

The history of the middle east intervention showed how little value the tax payer could extract out of military force when you win, nevermind when you lose.

 

[bobbymike]

the realpolitik line of thinking is how to extract the most value in a sale, not how to desperately hold onto it.

The reason people are fretting over Taiwan isn't as much to do with the island itself but contemplating how hard would it be to maintain a force posture in Asia against China once it falls.

Basically sell Japan, South Korea and Australia some hypersonic delivery vehicles and call it a day.

Sure this means little influence in the area afterwards, but it is not like that sort of thing helped the average tax payer much. (unless you buy into the whole mega currency manipulation concept)

The history of the middle east intervention showed how little value the tax payer could extract out of military force when you win, nevermind when you lose.

China will not come to the arms control table IMHO without “France and UK” east. Meaning Japan, South Korea and even Australia starts to develop independent nuclear forces.

 

[Grey Havoc]

s there any actual evidence or any attributable sources for any of those statements of “fact”?
Any by any chance any of that has any basis in fact and/ or reality why are the Russians and the Chinese airforces moving ahead with their own equivalents (sub-sonic stealthy flying wing bombers)?

Don't want to be rude but I agree with kaiserd, speculation is great fun but not unless you are cleared into the/a program then these are just speculation posts. China and Russia are moving forward with their so-called "stealth" bombers probably because of the USA's success with various programs plus the USA has in my opinion quite a "decades" lead with this technology which is real and dates back to the 1940's in regards to larger airframes. Russia dances to their own drum, China is nothing more than a copy-cat of other's tech, period. I will be impressed when China develops their own some day. Evidently, flying wings are the current benchmark for LO or others would not be developing their own aircraft based on wing-type designs, NGC shaping rules the day again.

Little or no speculation required on my part, I'm afraid. It is all in the public domain, including the USAF's own unclassified statements to Congress and to the media. I agree that it seems quite insane, but the Air Force has basically sacrificed pretty much everything in their quixotic quest for a 'low' unit cost ($550 million in 2010 dollars, $639 million in 2019 dollars.* Incidentally, at one stage early on the Air Force was even claiming it that would it be able to able to get that down to $500 million, apparently based on some rather optimistic cost projections from NG and in-house). A classic example of the means to an end becoming an end in itself, one could say. Speaking of the aforementioned doomed quest:

Air Force B-21 Raider Long-Range Strike Bomber

www.everycrsreport.com

Alternate link via the FAS website in case that one goes down:

https://fas.org/sgp/crs/weapons/R44463.pdf

The now again delayed nuclear capability along with some of the other things I raised in my last post are mentioned in the report. I should also note that there are a few amusing 'copy and paste' errors in the report.

With regards as to the Russian and Chinese flying wing bombers, I'll note a few things before I finish up for the evening and come back another day to that issue.

The first is, based on what little information about the H-20 that has become available publicly, and what slightly better info we have on the PAK DA, is that they both appear to be actual 'heavy' bombers or at worst, subsonic medium bombers at the higher end, very unlike what we now know about the B-21, with seemingly much greater payload, endurance and unrefuelled range than that aircraft, though just by how much remains to be seen. Any attempt to estimate and compare speeds at this point would be pure speculation. The only reason we can even reliably guess that their range and payload capabilities will greatly exceed those of the B-21 is because we roughly now know how large (or rather how small) the Raider is going to be.

The second point is that all three bombers originate from and are based on wildly different national policies, economic priorities and strategic doctrines, at least some of which are now in flux.

The third and last point, and the one that may be the most controversial, is that as of late July 2021, we may not truly know what the status of the PAK DA program currently is.


*No more recent figures available, which is interesting. If it had continued to even nominally follow the original cost baseline it should have now been $663,401,000 in today's money, rounded up.

 

[TomcatViP]

Don't forget that with poorer sfc any Chinese or Russian design have to be bigger than their US counterparts (more embarked fuel, more mass and volume).
Given that the next Gen of US engine could have 30% lower fuel consumption and that current F-135 are way more economical than anything both those countries have, you can probably up sfc by a safe 30%. See how the J-20 is massively bigger than the F-35.

Then there is stealth. With a probable higher refinement in the art of RCS reduction on the US side, it's a better ratio of payload to target destroyed that can be expected. Hence an increased need to carry relatively more ammo for the Russian /Chinese design.

Last but not least, as a smaller airframe will generate less drag, the increase in aero efficiency even aggravates the difference in size.

As you pointed out, the priority for the USAF beyond the technological outreach was to have a mass effect. Procurement costs have probably driven a lot of choices in what we will eventually be given to see.

 

[GreenBullet]

a smaller airframe will generate less drag

I am almost certain that is not correct.

 

[Josh_TN]

Several points I'd like to make on the last dozen or so posts:

I don't see how we get to a supersonic bombing platform that doesn't sacrifice range or RCS. The B-21/original B-2 shape is pretty much the most optimized low RCS arrangement possible while also having superior aerodynamic efficiency at sub sonic speed. A supersonic bomber is going to have to trade those attributes off regardless of how much money you are willing to spend.

In terms of reaction time, I don't see what a supersonic design brings to the table. Most previous designs still employed a sub sonic cruise phase with a supersonic end run as a means of avoiding defenses. Reaction time of a bomber aircraft seems rather moot in an error of ICBMs and land/sea based hypersonics; I would suggest the main concerns are an ability to reach the target area (ie range and low RCS / ESM / ECM / other low observables tech) and ability to deploy a large number of inexpensive weapons for a sustained campaign (there are a limited number of million $ cruise missiles).

We have no range figures for the B-21, but I'd be surprised if it didn't have a similar range to the B-2. Engine efficiency has gone up and airframe structure weight has gone down with composites. I believe a dry thrust version of the F135 is rumored to be the engine choice. If so, perhaps future upgrades to the F35 could directly translate to B-21 improvements as well. But if nothing else, the shape of the B-21 is more aerodynamic than the B-2: the saw tooth shape was a compromise for low altitude penetration. It made for inefficiencies at normal cruising altitude.

The only figure for the B-21 payload I've seen lists it as "30,000lbs +". This seems to compare relatively well with the B-2's ordnance load, the absolute heaviest of which I'm aware is a pair of GBU-57s (about 2x). Given integration with the SDB and SDB II, I'd think the war load would be quite sufficient for most target sets, particularly if the program is sufficiently cost effective enough to go beyond the stated ~100 aircraft.

I am unaware of any listing that states the size of the PAK-DA or H-20, though someone here posted an engine choice and configuration specs that implied a bomber somewhere between the B-2 and B-21. I do think it is fair to refer to the B-21 as a medium bomber, given the size of previous US heavies. But if the range is similar to B-2, I think one might still refer to it as a strategic bomber as well.

 

[Archibald]

Was reading Ben Rich memoirs this morning. He said they managed to turn the SR-71, an aircraft the size and weight of a B-58, into the RCS of a Piper Cub. Quite a notable feat !

 

[overscan (PaulMM)]

@Josh_TN the supersonic advocates were pushing for a supercruise bomber, able to fly its mission at say Mach 1.8 without using afterburner. The real radicals wanted hypersonic. Either would definitely decrease reaction time.

 

[Bhurki]

@Josh_TN the supersonic advocates were pushing for a supercruise bomber, able to fly its mission at say Mach 1.8 without using afterburner. The real radicals wanted hypersonic. Either would definitely decrease reaction time.

Yeah, but it would radically increase the amount of time it would take for the representatives to sign in to such exorbitantly priced projects. A supersonic/hypersonic analog to B-21 wouldn't cost just $600M a piece.

 

[overscan (PaulMM)]

@Josh_TN the supersonic advocates were pushing for a supercruise bomber, able to fly its mission at say Mach 1.8 without using afterburner. The real radicals wanted hypersonic. Either would definitely decrease reaction time.

Yeah, but it would radically increase the amount of time it would take for the representatives to sign in to such exorbitantly priced projects. A supersonic/hypersonic analog to B-21 wouldn't cost just $600M a piece.

Indeed - it would be complex and expensive. But a supercruise bomber is technically feasible, if you were willing to pay the money.

 

[Josh_TN]

@Josh_TN the supersonic advocates were pushing for a supercruise bomber, able to fly its mission at say Mach 1.8 without using afterburner. The real radicals wanted hypersonic. Either would definitely decrease reaction time.

Supercruise is still done at or near full military power. There would be range reduction even without reheat. That could be offset by more fuel, but there wouldn't be a free lunch.

 

[overscan (PaulMM)]

@Josh_TN the supersonic advocates were pushing for a supercruise bomber, able to fly its mission at say Mach 1.8 without using afterburner. The real radicals wanted hypersonic. Either would definitely decrease reaction time.

Supercruise is still done at or near full military power. There would be range reduction even without reheat. That could be offset by more fuel, but there wouldn't be a free lunch.

Sure - it would be easier in a Tu-22M style "theatre bomber" than a strategic bomber. My point was it wasn't a B-1 analog, able to fly supersonically for a short penetration phase only.