The Mother of All Bombers...

[Alamo]

Engines that won't have to be pulled for maintenance...
Sounds "Pie in the Sky" to me.

What will probably happen, is they will get their engines that don't get pulled, but they will just make it harder to fix, and more costly.

O ye of little faith!

This is probably not quite as outlandish is it first appears.

understand that they are talking about maintenance, not Repair. If you fly a bird down the intake of the engine, that’s a repair. If the engine simply runs and runs and runs, eventually it needs to be taken off and overhauled from end to end. That’s maintenance. (Also periodic maintenance that can be done on the engine while it is still hanging on the aircraft).

The B-52 airframe has a finite lifespan measured in number of flying hours. I think the majority of B-52 still flying have about 18000–20,000 flight hours (FH),And that’s over a span of about 50 years.

I believe the upper limit on the B-52 affects the wings first, at about 32,000 hours, give or take. So there’s about 12 to 14,000 flight hours left in the current fleet of B-52s (Average per aircraft). I don’t know what planning factor the Air Force is using, but when they look at the number of planned flying hours per year (important!: not including a war), then the B-52 will run out of life around 2040, plus/minus.

Rolls-Royce proposes using the F130 engine, used in some other USAF aircraft, which is based on a commercial engine called the BR 725. The BR 725 has a time between overhaul approximately 10,000 hours. This is the engine used in the Gulfstream 650, and part of the 700 series of engines used in previous Gulfstreams, so it has a maintenance history.

Assuming the changes to the engine the Rolls-Royce will make for the F130 to hang on the B 52 improve, rather than degrade, the endurance of it, then it is a good bet that the engine will not have to be pulled off the aircraft for overhaul during the remaining life of the aircraft.

These factors will be spelled out in the contract. The contractor is not going to sign up for an open ended promise that you’ll never have to pull an engine off a B52, But it will guarantee a certain Time between Overhaul (TBO), perhaps an average per engine, That effectively means the engine will never have to be overhauled during the remaining life of the aircraft.

I think Kelly in Avon was a maintainer, he might have more insight into this, but I was an acquisition guy for a while and this is kind of how these things play out in a contract.

 

[actaeon277]

Yes, I have "little faith".

Many veterans meet that description.

 

[Alamo]

Another cool pic:

[FONT=&amp]Two B-52 Stratofortress fly over Royal Air Force Station Fairford, United Kingdom, Aug. 22, 2020. Strategic bombers contribute to European theater stability as they are intended to deter conflict and offer a rapid response capability. (U.S. Air Force photo by Senior Airman Eugene Oliver)[/FONT]

https://strategypage.com/military_photos/military_photos_20200829185049.aspx

 

[chocktaw2]

This was/wasn't a factor, but, still a huge aircraft.
[video]https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker[/video]

 

[NKBJ]

Just a note of passing interest about bombers, the other day I ran across a video about sticking a turboprop engine in the nose of a B-17. The bomber would fly with the four wing mounted engines shut down.

 

[Thor]

This was/wasn't a factor, but, still a huge aircraft.
[video]https://en.wikipedia.org/wiki/Convair_B-36_Peacemaker[/video]

Six turnin' four burnin'. That was one big airplane.

 

[Alamo]

Yes, I have "little faith".

Many veterans meet that description.

Heh.

Also further consider that jet engines for large aircraft are a very well-studied and known piece of kit. Airlines rack up hundreds of thousands of flight hours per year and have kept close tabs on how long you can use an engine before you pull it off the wing. Even more important than flight hours are flight cycles: takeoff/landing. That's where the wear and tear accumulate, and airliner manufacturers and operators track this closely. Unless damaged by a bird strike or other mishap, jet engines are not removed from the wing for maintenance until a certain number of cycles are achieved, around 2500 to 3000 typically. An airliner that flies 8 hours from CONUS to Europe puts at least 8 hours on the flight clock, but only one flight cycle. That plane will likely return to CONUS starting the same day, or maybe the next day, for a second flight cycle and another 8 or 9 hours of flight. A CONUS airliner like SouthWest that flies 8 (or 10 or 12) hours within CONUS but stopping at four or five or six airports will have the same flight hours, but four or five or six times as a many cycles, thus the engines will need to be pulled chronologically sooner for maintenance.

Now consider the B-52. Peace time mission sorties tend to be lengthy, show the flag missions over long ranges, reconnaissance over the Indian Ocean, etc. It can fly 8,800 miles unrefueled, or about 17 or 18 hours, and longer if refueled. That's one cycle. It probably won't immediately go again like an airliner. Training sorties are often shorter and may include several cycles of touch-and-go for proficiency training, but still nothing like an airline schedule.

Exercises will temporarily ramp up the flight cycle and flying hour count, but only for a short while. Even war, for the B-52, with a mission every day, is unlikely to approach the airline schedule simply because we keep the BUFFs based way back, so mission sorties will be long.

Thus I don't think it's unreasonable to expect that most of the new engines on a B-52 will need to be pulled for the remainder of the B-52s life. Short of a war, the engines will not be used nearly as hard as in civilian life.

 

[Mr Evilwrench]

Of course, the bird strikes depend on whether the chicken was thawed before the test.

 

[NKBJ]

The frozen chicken story was a knee slapper.

 

[Hohn]

A classmate of mine from the Air Force academy is a 3rd generation BUFF pilot. Both dad and granddad flew it.

 

[Alamo]

This is a good home video of the BUFF landing in a heavy cross wind at (then) RAF Leuchars in Scotland.

If an airliner could do this everyone on the left side of the aircraft would have a forward facing window.


[video=youtube_share;TCUHQ_-l6Qg]https://youtu.be/TCUHQ_-l6Qg[/video]

 

[Alamo]

I didn't see it elsewhrre yet. RollsRoyce (and Indianapolis) wins:

Rolls-Royce to re-engine entire US B-52 bomber fleet

Rolls-Royce North America has been tapped to supply the replacement jet engines for the venerable Cold War-era B-52 Stratofortress nuclear heavy bomber. Beating out GE Aviation and Pratt & Whitney, the company will provide its F-130 turbofan engine to power the giant aircraft for the next three…

newatlas.com

 

[Lmo1131]

12 years after the Tarrant Tabor (1929), Curtiss Aircraft Co. built the 'first' B2, the Condor. 90' wingspan biplane, twin engine.

Very large format construction photographs > https://ww2aircraft.net/forum/threads/curtiss-b-2-under-construction.47433/

 

[Karl-just-Karl]

12 years after the Tarrant Tabor (1929), Curtiss Aircraft Co. built the 'first' B2,the Condor. 90' wingspan biplane, twin engine.

Very large format construction photographs > https://ww2aircraft.net/forum/threads/curtiss-b-2-under-construction.47433/

Wow, that is some really cool stuff! Thanks! The link was well worth the visit.

Those men of a different era were certainly men of a different era. I can't imagine the fortitude of this poor SOB sitting in the back of the engine nacelle, behind the fuel tank, tucked into his little cubby until it was time for action when he could stand up in the air-stream of the prop and defend his aircraft.

 

[cosermann]

Back in the day, in the early 80's, when Boy Scouts were still boys and still scouts, we were working on our aviation merit badge as a troop.

As part of it we did a weekend camp at Wurtsmith AFB. Got tours of and climbed all over B-52s, KC-135s, etc. Ate at the base mess. Slept on base. Dad, who never missed an outing, save 1, was an aeronautical engineer and I think enjoyed it as much as I did (maybe more). Great, GREAT time. Dad's gone now, and the base has been decommissioned, but I'll never forget.

 

[indyblue]

Being at the Indy 500 on raceday when the B2 flew over was quite the experience itself.
No noise on approach, nearly invisible, then the entire sky over the track turns dark as it makes a sweeping turn and then the roar as it departs.

I remember thinking I was glad they are on "our" side.

 

[armalitesheepdog]

How many people know in the 60s Bunker Hill Air Base then changed to Grissom AFB was home to a mach 2 supersonic nuclear bomber. The B-58 Hustler. It was a short lived sort of problem ridden bomber that only lasted 10 years but....It was one of the coolest looking Bombers capable of supersonic flight. When I was a kid visiting family up that way I remember the sonic booms that the people lived with.

 

[bobzilla]

How many people know in the 60s Bunker Hill Air Base then changed to Grissom AFB was home to a mach 2 supersonic nuclear bomber. The B-58 Hustler. It was a short lived sort of problem ridden bomber that only lasted 10 years but....It was one of the coolest looking Bombers capable of supersonic flight. When I was a kid visiting family up that way I remember the sonic booms that the people lived with.

And we had our own Broken Arrow incident. Apparently there is a spot on the grounds where the debris was buried.

 

[Thor]

They still have a Hustler in their air museum. Neat place to visit. And yes, that was one cool looking aircraft.

 

[Drewski]

I've never seen one live, in the air. Biggest plane I saw was a couple years ago, playing baseball with my kids at Wilson Park in Chicago when what looks like an Antonov AN-124 used the landing pattern that crosses our old neighborhood. The sound was like nothing I ever heard, and I've spent a good part of my life in airports. Best I could describe, if Darth Vader had a cargo plane, it would sound like this. Absolutely ominous. Everyone stopped to see what was going on.