USAF Fund B-52 Engine Replacement

[etudiant]

Thank you for that informative post, tdracer. It does underline the unforeseen risks of process changes.
Nevertheless, I remain unconvinced that maintaining TF-33s for another 50 years is anywhere nearly challenging enough to justify the huge cost of engine replacement.

[Turbine D]

tdracer,

Some of the manufacturing processes and alloys used 70 years ago have been effectively banned due to EPA and OSHA regulations.

Check your pm...

TD

[seafury45]

KenV,


a belated thank you for the explanation for weapon release envelope. I had forgotten just how much ironmongery can hang under a B-52.

[sandiego89]

Originally Posted by Carbon Bootprint

The JDF is already using the E-767. Wouldn't that make a suitable replacement platform, especially since Boeing is allegedly planning to continue 767 production?

I would imagine a KC-46 variant (767 based) will be the preferred platform to offer over a civil based 767 as it is already hardened, miles of extra wiring....

[ORAC]

Too big. Even if they didn’t go for a business jet they’d go for a P-3 variant - it already has a radar and it has already for provision f9r the appropriate consoles and comms etc.

In fact, that’s what Boeing has already selected and proposed.......

http://www.defensenews.com/air/2016/...-737-airliner/

[tdracer]

737 'Wedgetail' already exists for the AWACS mission.
No need to re-invent the wheel - not that it would stop them from trying...

[KenV]

Originally Posted by Heathrow Harry

Ken

given the continued apparent usefulness of the B-52 do you think they'd ever go for a replacement - a striaght sub-sonic, BIG, bomb truck that can carry just about anything you can think of?????

Or is it a bit like the fabled DC-3 replacement - so many built and available you could never get the price low enough to build a replacement??

Unlike the DC-3 the B-52 cannot fly forever. It WILL run out of service life. Once the B-21 (really? 21 because its the first 21st century design?!) ) gets into service and goes into full production, USAF will almost certainly have to start getting serious about replacing the B-52. Depending on the source, the B-21 might not have true strategic range, which if true will mean a true long range bomber will be needed to replace the B-52. And it will very likely have at least some stealth, so it won't look at all like the B-52. But it likely will not have the extreme level of stealth the B-21 has, which (reportedly) includes stealth against lower frequency radars (VHF and UHF) which the B-2 lacks, especially from the rear. But a lot can change in the meantime, so who knows? For all we know that new bomber might be optimized as a directed energy weapon platform, with the B-21 doing duty as the bomb truck. Who knows?

[KenV]

Originally Posted by George K Lee

Except that the engine used on the E-3 went out of production when the E-3 did, more than 25 years ago. The generation that succeeded it is also going OOP, replaced by the LEAP.

Ummm, no. Not completely true. The -2s on the AWACS and E-6s are OOP, but the -7s on the NG 737 (thousands built) are not and will be flying for quite some time. Further, the C-40 fleet, the Wedgetail, and the P-8 fleet all are equipped with -7s and thus will be around for quite some time, with the production line likely continuing for some time. Going from -2 to -7 would be a rather small generational jump. Putting LEAP engines on the AWACS aircraft will require significantly more of a development effort with not that much return on that additional investment.

That being said, will it make sense to keep those airframes going, or just replace them with something new? Like a 767 AWACS? Or more likely a 737 based Wedgetail? Or maybe even something based on a large biz-jet. It'll depend a lot on how much processing they want to do on-board vs how much raw radar data they want to datalink and then process off-board. If they're willing to do very high bandwidth datalinking of raw radar data with off-board processing, then something un manned might do the job. But there's only so much available real-time bandwidth. The last thing they want to do is use up the bandwidth and end up constraining everything else that needs robust comms. So my guess is that they'll opt for on-board processing. Which likely also means on-board decision makers. Which would seem to favor something a bit bigger than the biz jets. Maybe a 100 seat airliner, like the Embraer E-195 and Bombardier CS-100? Boeing's betting that the bottom end of the 737 range is just right. Who knows?

[ORAC]

737 'Wedgetail' already exists for the AWACS mission.
No need to re-invent the wheel - not that it would stop them from trying...

Different generations. Airframe is different, role is increasingly different, Radar is incredibly different - and would undoubtedly be multi-mode and underslung - and the vast majority of the processing and use would be distributed elsewhere.

We get back to the fact that even the 737 airframe is to big and a business jet would be more suitable.

[tdracer]

We get back to the fact that even the 737 airframe is to big and a business jet would be more suitable.

It's not as dramatic as it used to be, but if you're going to fly it a lot (1,000 hrs./year) most bus jets cost more/hr. to operate than a 737. That's one thing that has really boosted the 737 BBJ.
The problem with distributed sensors/processing is it has to be 100% jam proof - and needs to stay that way indefinitely. If it's 99% jam proof you can be sure the 1% will happen at the worst possible time.

[KenV]

Originally Posted by ORAC

We get back to the fact that even the 737 airframe is to big and a business jet would be more suitable.

But is it? If processing is on board (and there are LOTS of arguments against off-board processing) then besides the processor operators, it also makes sense to put the decision makers on board. That generally requires more volume than most biz jets provide. Further, once you go over about 1000 FH/yr, airliners are actually cheaper to operate than biz jets. So any cost advantage of a biz jet goes out the window if you actually fly the airplane.

But the really big issue is power generation. Biz jet engines and accessory gear box systems just are not designed to generate lots of power, and with active jamming, laser defense, laser offense, high power sensors, big on board processing systems, a robust comms suite, etc etc, the host aircraft needs to be able to generate LOTS of power. And finally, mission sets tend to creep upward, not downward. A bizjet based aircraft will likely not have a lot of growth margin. That's not to say that biz jets never make sense. Depending on the mission set and implementation, a biz jet may be ideal. But for the mission set of the current AWACS, you just couldn't cram all of the capability of that aircraft into a biz jet sized platform.

To put all this in perspective consider that the P-8 is based on the longer -800 airframe, not the shorter -700 airframe. And that's because the extra volume is needed. And the engines and nacelles of the P-8 have been modified with 180KVA generators. 360 kilowatts is a LOT of power. And when (not if) directed energy weapons start being fielded, they'll likely need to triple that power and get in the megawatt range.

[sandiego89]

While a 737/P-8 airframe size does seem to be what Boeing wants to pitch as the next AWACS, I do wonder if range/endurance wise something a KC-46/767, or even 787, sized airframe would be tempting especially for the USAF. 6,000 miles or 9+ hours endurance or so would be significant, especially when considering the Pacific basin. Yes I do realize there can be air-to-air refueling, but when you want endurance, internal space for racks and warm bodies (and spare crew), power, and external space for a large array, size does have a certain quality.


While Wedgetail, E-2, and bizjets work for many users the USAF might want to stay big.

[KenV]

Originally Posted by sandiego89

While a 737/P-8 airframe size does seem to be what Boeing wants to pitch as the next AWACS, I do wonder if range/endurance wise something a KC-46/767, or even 787, sized airframe would be tempting especially for the USAF. 6,000 miles or 9+ hours endurance or so would be significant, especially when considering the Pacific basin.

FYI, the 737 based P-8 has 10.5 hours endurance at 300NM on station, without inflight refueling. That's pretty much the limit of endurance for the crew. Add inflight refueling and the crew may expire before the aircraft landed.

As an aside, I see that this thread has once again wandered far afield and no one is discussing B-52 engine replacement any more. So to bring things back, while the B-52 engine replacement will involve the installation of engines designed for biz-jets, the B-52 installation will include more and bigger generators. Today, only the lefthand engine of each two-engine pair has a generator. The new installation will include one generator for each engine (thus eight total generators) and each generator will be larger than the 45KVA generators now on the B-52.

[KenV]

In a decision announced May 10, Boeing has been selected to serve as integrator for a program to install new commercial engines on the B-52 bomber. The Commercial Engine Replacement Program (CERP) is the latest in a series of modernizations that will ensure the aircraft remains mission-ready through at least 2050. “The (U.S.) Air Force has long recognized that new engines are the right choice to carry the B-52 into the future,” said James Kroening, B-52 program manager. “The aircraft is structurally viable for years to come, and it’s the only large, heavy bomber of its type in the current and future fleet. We are very proud to have been selected as integrator and excited to partner with the Air Force as the CERP gets under way.”

It looks like USAF is genuinely serious about this engine replacement program for B-52 and putting the infrastructure in place to make it happen. The only thing lacking at this point is the funding. And if I read the tea leaves right Congress supports the program and will find and authorize the funds.

[sandiego89]

Originally Posted by KenV

It looks like USAF is genuinely serious about this engine replacement program for B-52 and putting the infrastructure in place to make it happen. The only thing lacking at this point is the funding. And if I read the tea leaves right Congress supports the program and will find and authorize the funds.

Agree that the timing seems right- congress and the administration do not seem to be at all concerned about deficit spending at this time, and plenty of talk about the need to "improve" the military.

I do get that B-1 and B-2 bed down/phase out are part of the long term plans, but think the USAF and congress will need to get serious about that for funding and credibility sake. It will take some time to ensure the B-21's are up and running, but it looks like there will be period where FOUR bomber programs are up and running. That does get expensive.

I note here that Ellsworth, Dyess and Whiteman are likely slated to be the three B-21 bases, which seems like a natural transition of the types at those bases. Minot and Barksdale remain with the B-52. Air Force picks 3 bases for new B-21 Raider bomber - Business Insider The magic will be in the timing, and if/how many upgrades the B-1 and B-2 will need to keep them going. A slip is B-21 fielding could be costly in many ways, and doubt anyone wants a bomber gap at their base.

[RAFEngO74to09]

Program proceeding apace - final RFP end-March to Summer - selection by end-2020 - contract early-2021.

Interviews with P&W and G-E:

P&W would save 5,400 lbs on 8 x engines - in similar dimensions - and offer 40% range increase.

You Tube

You Tube

[RAFEngO74to09]

Original Boeing video from 2017 explaining the benefits of the re-engine program to keep in service beyond 2050:

You Tube

TF33 overhaul cost in 1996 per engine was $230K - $2M by 2017.
New engines will not require a depot level overhaul at all during the projected life to 2050.
Overall savings of $10 Billion in engine operating costs to 2050.

[ORAC]

https://www.flightglobal.com/fixed-w...138099.article

US Air Force issues draft request for proposal to replace B-52 engines

[ORAC]

https://www.airforcemag.com/usaf-rel...ted-july-2021/

USAF Releases B-52 Engine Replacement RFP, Award Expected July 2021

[Asturias56]

It should have been done years ago