Boeing B-52J / B-52 Re-Engining

[WatcherZero]

There were three B-52As built, what happened to the other two?

52-003 was the one converted for NASA. 52-002 was used as a B-52G development testbed and re-designated XB-52G and then used as a ground trainer from 1959, the other 52-001 was scrapped at Tinker in April '61

 

[NMaude]

the other was scrapped at Tinker in April '61

A disgraceful act of vandalism, both of the other B-52As should've been preserved.

 

[_Del_]

So thats 10 different engines the B-52 has had in its lifetime.

Well, very technically, it flew with a JT9D briefly, too. So that'd be 11 in flight, if not service.

 

[F119Doctor]

The one leased to GE had one TF39 or one CF6 mounted on an inboard pylon for flight test purposes. The remaining 6 engines were the J57 engines, so they didn’t have the outboard engine out controllability concern, and they could be throttled asymmetrically to offset the higher thrust from the test engine on the inboard pylon as necessary.

 

[Scott Kenny]

The point is still that the B-52Hs still in service were built as -H models.

Planes built as B-52Gs were not converted from Ds or whatever, they were all built as Gs. (XB wasn't operational, that was strictly an R&D prototype).

This is the first time in history that planes built as one model of B-52 are being converted en masse to another type.

 

[BlackBat242]

That consideration is why it took so long to actually re-engine them, especially considering the number of available engines.

I thought the convoluted process for finally gettng a new engine was more funding/resolve driven than anything else. Yes, some of the earlier proposals were dropped as the engine oput situation could not be met with repalcing 8 with 4 and ground clearance considerations as well. I probably missed something over the years....

Enjoy the Day! Mark

They could have been re-engined one-for-one in the early 1980s with the 18,900 lbf JT8D-209 (certified 1979 for MD-80 airliners and for B727 re-engining (replacing the side-mounted engines) which were more fuel-efficient than the TF33s (JT3D) - and 4" smaller in diameter. The engine was retired from mainline airline use in 2020.

The late 1980s/early 1990s saw an opportunity for a one-for-one replacement program with the B-2's engine, the F118. This engine was flight-certified (for the B-2) in 1985 (and was also installed in the U2S fleet in 1998+), and is even 2.5" smaller in diameter than the JT8D-209 while using much less fuel than the TF33 (.375 lb/lbf/hr vs .510 for the JT8D-209 and .52 for the TF33-P-3).

A second chance for the JT8D-209 engine came in 2001 when the 200-series JT8Ds were certified as a TF-33 replacement engine for military and civilian use, and new 200 series JT-8Ds were produced as late as 2011 for some military aircraft.

 

[Scott Kenny]

They could have been re-engined one-for-one in the early 1980s with the 18,900 lbf JT8D-209 (certified 1979 for MD-80 airliners and for B727 re-engining (replacing the side-mounted engines) which were more fuel-efficient than the TF33s (JT3D) - and 4" smaller in diameter. The engine was retired from mainline airline use in 2020.

The late 1980s/early 1990s saw an opportunity for a one-for-one replacement program with the B-2's engine, the F118. This engine was flight-certified (for the B-2) in 1985 (and was also installed in the U2S fleet in 1998+), and is even 2.5" smaller in diameter than the JT8D-209 while using much less fuel than the TF33 (.375 lb/lbf/hr vs .510 for the JT8D-209 and .52 for the TF33-P-3).

A second chance for the JT8D-209 engine came in 2001 when the 200-series JT8Ds were certified as a TF-33 replacement engine for military and civilian use, and new 200 series JT-8Ds were produced as late as 2011 for some military aircraft.

The TF33s soldiered on because the USAF retired all the C-141s and suddenly had hundreds if not thousands of spare engines available.

Now, though, the TF33s are all used up and long out of production.

 

[BlackBat242]

1 B-52A was converted to a NB-52A with an additional pylon and wing flap cutout section
7 B-52B's were converted to C's under project Sunflower
1 B-52B was converted to a NB-52B for NASA with an additional pylon and wing flap cutout section
1 B-52E was converted to a NB-52E with added canards and modifications to reduce vibrations and vulnerability to wing gusts for low level flying
1 B-52E was leased to General Electric as the JB-52E and had both TF39 and CF6 engines fitted


The first two prototypes were fitted with YJ57-P-3 engines
The A's were witted with J57-P-1W, The B's and D's had the J57-P-29W, J57-P-29WA or a J57-P-19W all with the same non-water injected output of 10,500 lbf
The F and G's had the J57-P-43WB
The H had the TF33-P-3
And now the H's will be re-designated J's and be refitted with a Rolls-Royce F130

So thats 10 different engines the B-52 has had in its lifetime.

And one B-52E was loaned to P&W as a NB-52E and tested the JT9D engine.

JB-52E (B-52E-55-BW 57-0119 [MSN 464108] bailed to GE Flight Test January 1966 and converted to JB-52E as engine testbed for TF39 for the C-5A, and for CF6. Put in long-term storage in 1972. Decommissioned by GE in 1980 and towed to the south end of the lakebed at Rogers Dry Lake (Edwards AFB). Years later in 1991 it was broken up by explosive charges according to the SALT treaty. It seems that a Russian photo interpreter noticed that the plane seemed to be intact, and insisted that it be rendered inoperative. Seen at Rogers Dry Lake in three pieces). :




NB-52E (B-52-85-BO 56-0636 [MSN 17319] used as a test airframe by Pratt & Whitney until 7/30/81. Used to trial some of its engines, including the JT9D turbofan used on the Boeing 747. To MASDC as BC275 July 30 1981. Scrapped February 1994). :

 

[NMaude]

It seems that a Russian photo interpreter noticed that the plane seemed to be intact, and insisted that it be rendered inoperative.

That Russian photo interpreter should've been given a boot up his arse, that aircraft was derelict and blowing it up just an unnecessary bit of vandalism.

 

[jcf]

Why haven't they? They've had literally decades to digitise the drawings.

Who was going to pay for doing the digitizing? Boeing isn't going to incur the cost, and you're also assuming that all of the drawings still exist and are easily to hand. It would be
a large and expensive project to track down all of that old data and convert it to digital
formats. It ain't a matter of just feeding a drawing into a scanner.

 

[F119Doctor]

The TF33s soldiered on because the USAF retired all the C-141s and suddenly had hundreds if not thousands of spare engines available.

Now, though, the TF33s are all used up and long out of production.

The C-141 engines were TF33-P-7, which had 21K thrust and were heavier, vs the TF33-P-3 engines on the B-52H with 18K thrust. They are not interchangeable, but may have provided some spare part to the B-52H fleet. The P-7 engine is almost the same as the TF33-P-100 on the E-3 AWACS without the enlarged gearbox needed for the larger electrical generators needed for the AWACS application.

 

[NMaude]

Who was going to pay for doing the digitizing? Boeing isn't going to incur the cost

The DOD would pay for it but Boeing could've done done this itself, remember Boeing is a large multi-billion dollar company, it has the financial means to do such a project.

you're also assuming that all of the drawings still exist and are easily to hand.

I suspect that they are all still on hand as the B-52H is very much still in service and if any drawings have been lost or destroyed without DOD authorisation someone in Boeing's engineering department going to be torn a new arsehole.

 

[TomS]

The DOD would pay for it but Boeing could've done done this itself, remember Boeing is a large multi-billion dollar company, it has the financial means to do such a project.

For what return though? Boeing isn't going to invest its own money without some prospect of a payback, and I just don't see it. (Not to mention, they are hemorrhaging money right now.)

DoD is making a digital twin of the B-1B. It's a 6+ year effort that is going to cost north of $100 million.

The Air Force Is Stripping a B-1 Bomber Down to Its Bolts to Make a Digital Twin

One B-1B Lancer bomber is having a lengthy breakdown -- but for good reason.

www.military.com

Air Force awards $100 million to continue WSU NIAR’s B-1 Digital Engineering program

On March 9, 2022, the B-1 System Program Office (SPO), Tinker AFB, OK awarded a six-year, $100 million follow-on contract to Wichita State University’s National Institute for Aviation Research (NIAR) to continue the B-1’s Digital Engineering (DE) transformation. The National Center for...

www.wichita.edu

DoD is also tinkering with one for the B-52 as an SBIR. I don't think this one aims for the level of fidelity in the B-1 effort, given the relatively little money being spent.

Creating a digital twin of legacy aircraft

SBIR Creating a digital twin of legacy aircraft issued by Department of the Air Force due 10/18/23

www.highergov.com

 

[navel_guy21]

what would happen if B52 went over mach1

 

[TomS]

what would happen if B52 went over mach1

Pieces would start coming off the plane well before that.

 

[FighterJock]

The B-52 would sadly break apart, and it is something that no BUFF pilot has ever attempted or ever will.

 

[mkellytx]

The B-52 would sadly break apart, and it is something that no BUFF pilot has ever attempted or ever will.

That of course presupposes there's enough thrust to overcome the drag rise. The old bird will quite happily do .92 M at 20,000 ft, been there done that and even dropped a MALD while we had both HSAB's on the jet. VNE is 90% of VD (been there done that also, but not on the BUFF) which comes out to 1.02 M. Usually, flutter is the main concern. If you Google B-52 Flutter Test this NASA report is the top result.

https://ntrs.nasa.gov/api/citations/19760003021/downloads/19760003021.pdf

After a quick scan of that paper my thought is that the BUFF will only get close to Mach if you dive it. The other thing to remember is that the BUFF is a 2 G airframe, so it doesn't take much G to rip the wings off or permanently deform the structure. You might well break Mach, if you dive high enough, but then you'd probably rip the wings off in the pull up. As @FighterJock said, no sane pilot will do that.

 

[Kiltonge]

Both the DC-8-43 and Global 8000 have been dived through Mach 1 and recovered without shedding their wings... and they're 2g rated.

Not something routine but not impossible either.

 

[Archibald]

747 too (from memory)

 

[WatcherZero]

747 too (from memory)

An Evergreen International cargo 747-100F did break Mach 1.25 in a dive due to an INS failure (Mach 1.25 is estimated the instruments only recorded 0.98) but, but when it landed a 3x15ft hole was found in the right wing along with damage to both the wing and tail flaps!