Northrop Grumman B-21 Raider (LRS-B)

[Brett Davidson]

Considering how ruthless they've been in shaping the plane, I think it unlikely that there'd be any odd bumps on the final design. Perhaps test equipment or an antenna peculiar to the prototype?

 

[Scott Kenny]

Considering how ruthless they've been in shaping the plane, I think it unlikely that there'd be any odd bumps on the final design. Perhaps test equipment or an antenna peculiar to the prototype?

The light doesn't lie, however. There's a well-faired bump on the tail.

 

[Josh_TN]

The light doesn't lie, however. There's a well-faired bump on the tail.

It might be a test article, but also that would be an incredibly obscure place to generate a radar reflection, especially at 50,000 feet.

 

[4decaa]

Scott is right, that light don't lie!
Considering B-21 test articles are essentially production aircraft, I don't know why there would be anything different on the test aircraft in terms of physical structure. Other than the air probe(s).

There is something (on the back of the aircraft) that the engineering team needed to accommodate for, and this something was worth a rear-aspect RCS penalty.

 

[Training_Dummy]

Closing in on a decade since the announcement of the award. Hoping F-47 does better.

 

[Scott Kenny]

There is something (on the back of the aircraft) that the engineering team needed to accommodate for, and this something was worth a rear-aspect RCS penalty.

I'm leaning towards SATCOM antenna bump, personally. This would shield the antenna from the entire frontal aspect even while the Raider is at 35-40kft, and still let the antenna see the whole sky.

 

[Josh_TN]

Closing in on a decade since the announcement of the award. Hoping F-47 does better.

Not bad for a stealth bomber. It is in LRIP.

I doubt F-47 will do much better.

 

[bring_it_on]

Closing in on a decade since the announcement of the award. Hoping F-47 does better.

They are flying weekly, and are getting ready to dramatically expand the flight test program. Two LRIP contracts awarded (being executed) and another two in long lead procurement. I think the program has done rather well given the initial delay due to protest, a pandemic that disrupted supply chains and workforce and a whole host of other considerations (to include that developing and producing a stealth bomber is not exactly a cakewalk). Most importantly, they are within the schedule (and cost) margins put forward by the AF RCO. That's quite impressive all things considered.

NGAD is intended to do a lot better than this. For starters, the time to first flight is expected to take half as long as that on B-21. Low Rate production likewise will probably begin at least a couple of years to the left of when it happened on the B-21. If not even sooner. I would not rule out an LRIP award (or two) before the end of the decade for deliveries to first units beginning in the early 2030s (I expect at least one LRIP award in the 2028-2030 timeframe for 2032 delivery).

 

[Training_Dummy]

thanks for the counterpoints. I guess more than anything I thought Raiders reliance on high TRL subsystems and NGs experience with the planform might have resulted in even faster progress, but that’s probably the anxiety that comes with seeing half of the deployable B-2 fleet making holes in a desert half a world away and realizing Raider can’t come soon enough. In the end, the government seems to be working with NG to accelerate and potentially increase deliveries.

 

[Josh_TN]

thanks for the counterpoints. I guess more than anything I thought Raiders reliance on high TRL subsystems and NGs experience with the planform might have resulted in even faster progress, but that’s probably the anxiety that comes with seeing half of the deployable B-2 fleet making holes in a desert half a world away and realizing Raider can’t come soon enough. In the end, the government seems to be working with NG to accelerate and potentially increase deliveries.

The B-21 benefited from being run by the RCO with a stipulation that all items inside it were at TRL-6 or above. Basically, it had to be more or less a demonstrated technology to be considered. Luckily, the U.S. has a lot of tech just on the shelf, relative to it’s competitors.

 

[Training_Dummy]

Was just also doing a bit of legwork - starting from the first a/c, Raider was supposed to fly with installed mission systems, as opposed to pumping out a few test articles with core flight systems only and weights to simulate the rest, just to fill out the test flight envelope as quickly as possible. Non-trivial factor.

 

[bring_it_on]

The B-21 benefited from being run by the RCO with a stipulation that all items inside it were at TRL-6 or above.

That's not a RCO thing. That's an actual requirement for a MDAP entering EMD. I believe this was set in place in the mid 2000s and further reinforced in 2012. These would have been the criteria regardless of which program office managed the LRS-B.

“TRL 6 (required for approval at Milestone B), must be demonstrated (hardware) or validated (software) in a relevant environment.

https://www.cto.mil/wp-content/uploads/2023/07/TRA-Guide-Jun2023.pdf

The National Defense Authorization Act (NDAA) of 2006 established statutory law for the Milestone Decision Authority to certify that all critical technologies (i.e., referred to as critical technology elements) have been demonstrated in a relevant environment (i.e., TRL 6) before granting an MDAP approval to enter EMD (NDAA, 2006). With the advent of key legislation and resulting DoD acquisition reform initiatives, weapon systems programs are now required to enforce a technology development strategy that can foster true risk reduction prior to entering systems development.

https://idstch.com/industry/us-dod-...nstrations-major-defense-acquisition-programs
I believe the B-21 benefited a lot from RCO's tight control of requirements, and the authority to change requirements residing at a very high level and the resultant benefits of requirements stability. Digital capabilites also contributed leading to a very mature and stable first aircraft configuration and mission system incorporation. NGAD will be head of B-21 even in these areas..

Slightly off topic but the DOD IG had some questions regarding NGAD's TRA and whether it was even ready to push through into EMD in FY24/25. They backed off once Kendall put it on ice and have been quite since but clearly that's still a requirement for it to enter that phase of the program as it is the law.

 

[Josh_TN]

Ok, fair correction, but broadly I think my post was not inaccurate: the LRSO program that became the the B-21 benefited from an RCO development that specifically required a high level of technical maturity for anything going into the aircraft. That is in stark contrast to the NGB project that predated it. And not for nothing, in stark contrast to H-20 or PAK-DA, which for both countries would be massively ground breaking aircraft development.

 

[bring_it_on]

Ok, fair correction, but broadly I think my post was not inaccurate: the LRSO program that became the the B-21 benefited from an RCO development that specifically required a high level of technical maturity for anything going into the aircraft. That is in stark contrast to the NGB project that predated it. And not for nothing, in stark contrast to H-20 or PAK-DA, which for both countries would be massively ground breaking aircraft development.

Yes largely correct. They added 5-10 years to the schedule and reduced requirements and technology on the LRS-B as they transitioned from NGB. The added time, and lower technology and size meant a less capable but a lot more affordable aircraft.

 

[NMaude]

The added time, and lower technology and size meant a less capable but a lot more affordable aircraft.

Basically getting an aircraft good enough for the and at a price that won't break the bank enabling large numbers to be built.

 

[In_A_Dream]

With the upgrades being made to the B-21 line at Palmdale, any guesses on the production rate once it completes LRIP?

 

[skyblue]

What capabilities were lost in the transition from NGB to B-21?

 

[kmrumble]

With the upgrades being made to the B-21 line at Palmdale, any guesses on the production rate once it completes LRIP?

With 24 months notice and planning, they could probably get up to 24-30 aircraft per year, which was the max capacity planned for the B-2 in that facility. But, to get there, the government would have to guarantee the increased quantities and pay the capital/termination charges if Congress doesn't appropriate the money years from now. That big a change to the program plan would probably break the conditions that the NTE prices for units 21 to 40 were based on, and necessitate a renegotiation. Despite the talk, my guess is that it will fall into the "too hard to do" category.

 

[yeetmahboi]

What capabilities were lost in the transition from NGB to B-21?

Supersonic classified

 

[Ozair]

With 24 months notice and planning, they could probably get up to 24-30 aircraft per year, which was the max capacity planned for the B-2 in that facility. But, to get there, the government would have to guarantee the increased quantities and pay the capital/termination charges if Congress doesn't appropriate the money years from now. That big a change to the program plan would probably break the conditions that the NTE prices for units 21 to 40 were based on, and necessitate a renegotiation. Despite the talk, my guess is that it will fall into the "too hard to do" category.

24 to 30 a year..., I think that is highly doubtful. Likely with even 2 years notice I doubt most of the supply chain could scale that quickly. Moving to 15 in a two year time frame would be an exceptional result but to 3x the production to ~30 in a two year period, sorry I find that very hard to believe.

 

[Scott Kenny]

What capabilities were lost in the transition from NGB to B-21?

Any of the really bleeding-edge, undeveloped technologies that were mentioned.

B-21 required everything to be at TRL-6 to be included in the plane.

 

[bring_it_on]

As mentioned previously, that was the a mandate not a program specific choice. Had NGB entered production after the mid 2000's or in the 2010s it would have had to comply with the same as well.

 

[bobbymike]

https://www.airandspaceforces.com/allvin-more-b-21s-may-be-necessary-b-52j-upgrade-goes-awry/?src=dr

 

[Sferrin]

https://www.airandspaceforces.com/allvin-more-b-21s-may-be-necessary-b-52j-upgrade-goes-awry/?src=dr

JFC, how hard is it to re-engine an aircraft? They went from the B-52G to B-52H in less time they they've spent on this already.

"There was no B-52H prototype as such, but the TF33 turbofan engines were first tested on a B-52G (serial number 57-6471), the aircraft being temporarily redesignated YB-52H. Following the tests, the aircraft reverted to standard B-52G configuration. The first true B-52H flew on July 20, 1960.

Delivery of the B-52H to operational units began on May 9, 1961 when the 379th Bombardment Wing at Wurtsmith AFB in Michigan received its first aircraft. The last B-52H was delivered to the 4136th Strategic Wing at Minot AFB on October 26, 1962, bringing production of the Stratofortress to an end."
https://www.aircraftinformation.info/JB_AIF/usaf_bombers/b52_17.html

 

[Training_Dummy]

not allowed to criticize or question timelines of key defense programs. everything is on track and purposeful, and more complicated than we know, so don't worry our pretty heads. hush.

 

[JoshuaH]

not allowed to criticize or question timelines of key defense programs. everything is on track and purposeful, and more complicated than we know, so don't worry our pretty heads. hush.

They can setup slack “baseline schedule” to fall back on whenever they want, but the original expected first flight for B-21 was before the end of 2021…(Granted that estimation was before Covid, so there’s that)

 

[JoshuaH]

Now I am more curious why the second prototype has not seemed to taken off yet. If the first prototype is doing more than one flight per week since September last year, and more than two flights per week since March, it might be exceeding the number of flights of the B-2 first prototype in its entire test campaign…

 

[Hydroman]

JFC, how hard is it to re-engine an aircraft? They went from the B-52G to B-52H in less time they they've spent on this already.

"There was no B-52H prototype as such, but the TF33 turbofan engines were first tested on a B-52G (serial number 57-6471), the aircraft being temporarily redesignated YB-52H. Following the tests, the aircraft reverted to standard B-52G configuration. The first true B-52H flew on July 20, 1960.

Delivery of the B-52H to operational units began on May 9, 1961 when the 379th Bombardment Wing at Wurtsmith AFB in Michigan received its first aircraft. The last B-52H was delivered to the 4136th Strategic Wing at Minot AFB on October 26, 1962, bringing production of the Stratofortress to an end."
https://www.aircraftinformation.info/JB_AIF/usaf_bombers/b52_17.html

Now I am more curious why the second prototype has not seemed to taken off yet. If the first prototype is doing more than one flight per week since September last year, and more than two flights per week since March, it might be exceeding the number of flights of the B-2 first prototype in its entire test campaign…View attachment 771031

AV-1 also performed the initial LO test work.

 

[Ozair]

https://www.airandspaceforces.com/allvin-more-b-21s-may-be-necessary-b-52j-upgrade-goes-awry/?src=dr

I'm not confident there is a solid link between B-52J not going well and increasing the B-21 fleet. The aircraft will have very different missions and using a B-21 to replace what a B-52J would do seems a waste.

 

[Sferrin]

I'm not confident there is a solid link between B-52J not going well and increasing the B-21 fleet. The aircraft will have very different missions and using a B-21 to replace what a B-52J would do seems a waste.

I don't see why it's taking so long for the B-52J upgrade. They say issues with the radar and I'd have to ask why they don't just grab something off the shelf. It's not like there is a lack of AESAs they could shove in the nose.

 

[Ozair]

I don't see why it's taking so long for the B-52J upgrade. They say issues with the radar and I'd have to ask why they don't just grab something off the shelf. It's not like there is a lack of AESAs they could shove in the nose.

It was off the shelf, was an APG-79 turned upside down with added 82 bits. Perhaps trying to fit a modern cooled AESA radar is more difficult than expected unless RTX offered more than they could actually deliver.

 

[JoshuaH]

I'm not confident there is a solid link between B-52J not going well and increasing the B-21 fleet. The aircraft will have very different missions and using a B-21 to replace what a B-52J would do seems a waste.

I would consider it more as an excuse to just buy more B-21s…

 

[EmoBirb]

The aircraft will have very different missions and using a B-21 to replace what a B-52J would do seems a waste.

Sooner or later the B-52 will be replaced by the B-21 anyway. Be it just the B-21, or the B-21 in conjunction with unmanned force multipliers. So if B-52J is late, then some B-21s will just do that earlier.

 

[Scott Kenny]

Sooner or later the B-52 will be replaced by the B-21 anyway. Be it just the B-21, or the B-21 in conjunction with unmanned force multipliers. So if B-52J is late, then some B-21s will just do that earlier.

Not exactly.

The B-52 in the strategic mission carries 20x ALCMs. That's ~2.5x the load of a single B-21. So replacing the BUFF with Raiders means that you need to buy over 100 additional Raiders.

 

[JoshuaH]

Not exactly.

The B-52 in the strategic mission carries 20x ALCMs. That's ~2.5x the load of a single B-21. So replacing the BUFF with Raiders means that you need to buy over 100 additional Raiders.

If it’s just dropping ALCMs/LRSOs from 2000+ nmi away, then a C-17 can probably carry 27+ missiles with rapid dragon in a single load (3 pallets, 3-by-3 missiles in each pallet).

 

[Josh_TN]

It was off the shelf, was an APG-79 turned upside down with added 82 bits. Perhaps trying to fit a modern cooled AESA radar is more difficult than expected unless RTX offered more than they could actually deliver.

I suspect a lot of the integration issues are associated with adapting 21st century tech to what is otherwise a 1950s machine. If you read up on how antiquated the maintainance is on these things, it would make more sense.

Google “confessions of a B-52 maintainer “ or something similar. Trying to make anything on that aircraft digital is going to be hard.

 

[Josh_TN]

If it’s just dropping ALCMs/LRSOs from 2000+ nmi away, then a C-17 can probably carry 27+ missiles with rapid dragon in a single load (3 pallets, 3-by-3 missiles in each pallet).

Well I doubt anyone is giving/building PAL enabled kits for cargo planes, for starters

 

[EmoBirb]

Not exactly.

The B-52 in the strategic mission carries 20x ALCMs. That's ~2.5x the load of a single B-21. So replacing the BUFF with Raiders means that you need to buy over 100 additional Raiders.

That's why I said that unmanned systems most likely play a part too.

The B-52 won't make it much further past 2050, the B-21 is intended to serve well beyond that. The USAF won't design a 50s style bomber to replace the B-52.

So it's either that the B-21 + UAV missile carriers takes over if a one to one replacement with regards to missile capacity is required. Or such a load is deemed unnecessary/will be deemed unnecessary for that time frame.

 

[Scott Kenny]

That's why I said that unmanned systems most likely play a part too.

The B-52 won't make it much further past 2050, the B-21 is intended to serve well beyond that. The USAF won't design a 50s style bomber to replace the B-52.

So it's either that the B-21 + UAV missile carriers takes over if a one to one replacement with regards to missile capacity is required. Or such a load is deemed unnecessary/will be deemed unnecessary for that time frame.

Nuclear weapons gets weird for that...

Whatever is carrying the ALCMs (err, I guess LRSOs) needs PAL gear. So I'm not expecting UAVs to be nuclear weapon carriers.

 

[bring_it_on]

but the original expected first flight for B-21 was before the end of 2021…(Granted that estimation was before Covid, so there’s that)

'expected first flight' is not a milestone. You seem to be piecing it by looking at public statements. There is always a threshold and objective range built on such milestones so that they can track schedule. By all indications, the B-21 has held its schedule and cost. Unless you can show otherwise.