rlwynn
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Re: Best Replacement Engines for the B52

Wed Jul 18, 2018 7:34 pm

DavidMHoffman wrote:
rlwynn wrote:
Why not a new order for new TF33s. There is nothing wrong with them outside that they are old and the is not the big supply of new parts. PW couls easily do it.


That does nothing to lower per flight hour or per ton-mile maintenance costs or reduce per ton-mile fuel consumption.


New engines would lower the maintenance and fuel consumption or power of the TF33 is not an issue as the Air Force has said. They have said that the TF33 has too much power for how they want to fly the B-52.
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LightningZ71
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Re: Best Replacement Engines for the B52

Wed Jul 18, 2018 10:08 pm

I'm beginning to think that this will be perpetually kicked down the road until there is so little life left in the B-52 that any reengining project will not fly long enough to recoup it's costs. At this point, RR has introduced the Pearl (a BR700 development) that seems an even better fit than the current suggested BR700 series engines. With it's promised improvements over the existing BRs, there may never be a reason to refuel a B-52 for a mission again. (OK, I'm exaggerating, but not by much!)
 
GalaxyFlyer
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Re: Best Replacement Engines for the B52

Thu Jul 19, 2018 3:18 am

Well. for one, TF-33s haven’t been built since about 1970. It’s doubtful P&W could build new one and are not interested in doing so.

GF
 
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trpmb6
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Re: Best Replacement Engines for the B52

Thu Jul 19, 2018 3:20 pm

The BR725 is one of the best options. It's already at good production rates thanks to the G650, has the performance, improved efficiency and will have a fairly minimal structures impact on the wing. It's a logical choice. What I don't understand is what the pentagon is waiting on. The only potential snagup is the Air Force's love for PW engines.
 
Ozair
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Re: Best Replacement Engines for the B52

Thu Jul 19, 2018 9:20 pm

trpmb6 wrote:
The only potential snagup is the Air Force's love for PW engines.


Hopefully not going too off topic but does anyone have some justification for the depth of the USAF/P&W relationship, is there a watershed moment when this relationship cemented?
 
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kanban
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Re: Best Replacement Engines for the B52

Thu Jul 19, 2018 10:25 pm

By the time the Air Force has a plan, done some feasibility testing and congress awards some money, we may well be at 2025 or later and the whole issue becomes moot .. and then again certain diehards will want to continue a re-engine program even when the planes are mothballed.
 
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Spacepope
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 4:42 am

GalaxyFlyer wrote:
Well. for one, TF-33s haven’t been built since about 1970. It’s doubtful P&W could build new one and are not interested in doing so.

GF


The E-3 fleet wasn't produced till 1977 with the final USAF TF-33 engined example built in 1984. Did they just install old stored engines on these brand new aircraft?
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mmo
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 6:55 am

kanban wrote:
By the time the Air Force has a plan, done some feasibility testing and congress awards some money, we may well be at 2025 or later and the whole issue becomes moot .. and then again certain diehards will want to continue a re-engine program even when the planes are mothballed.


Current plans, with the re-engining, call for the BUFF to be in service until at least 2050.
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trpmb6
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 1:40 pm

Ozair wrote:
trpmb6 wrote:
The only potential snagup is the Air Force's love for PW engines.


Hopefully not going too off topic but does anyone have some justification for the depth of the USAF/P&W relationship, is there a watershed moment when this relationship cemented?


There might be more to it but I think there are some servicing agreements that are favorable. More importantly though the flight lines are familiar with PW products and know how to work on them.

Could also be that they are trying to keep a third engine manufacturer floating haha. And that PW is mostly US based right? RR being foreign may be a potential snagup that I hadn't really thought too much about.
 
tjh8402
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 3:42 pm

Ozair wrote:
trpmb6 wrote:
The only potential snagup is the Air Force's love for PW engines.


Hopefully not going too off topic but does anyone have some justification for the depth of the USAF/P&W relationship, is there a watershed moment when this relationship cemented?


P&W is the one engine maker that predates the Air Force itself, having built engines for the Army Air Force since before WW2. They also seemed to take the lead on larger jet engines early on. They were the OEM that Boeing selected for the B-52, KC 135, and all the 707 derivatives. GE didn’t really get into the big engine game till the CF6, which is on the VC-25s and C-5M. There have been plenty of other GE powered planes in the Air Force. Plenty of combat planes like F-86, F-4, A-10, B-1, B-2, and F-16 have used GE (GE actually overtook Pratt as the preferred F-16 engine), and the KC-135s are pretty much all CFM powered.
 
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Revelation
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 6:07 pm

tjh8402 wrote:
Ozair wrote:
trpmb6 wrote:
The only potential snagup is the Air Force's love for PW engines.


Hopefully not going too off topic but does anyone have some justification for the depth of the USAF/P&W relationship, is there a watershed moment when this relationship cemented?


P&W is the one engine maker that predates the Air Force itself, having built engines for the Army Air Force since before WW2. They also seemed to take the lead on larger jet engines early on. They were the OEM that Boeing selected for the B-52, KC 135, and all the 707 derivatives. GE didn’t really get into the big engine game till the CF6, which is on the VC-25s and C-5M. There have been plenty of other GE powered planes in the Air Force. Plenty of combat planes like F-86, F-4, A-10, B-1, B-2, and F-16 have used GE (GE actually overtook Pratt as the preferred F-16 engine), and the KC-135s are pretty much all CFM powered.

Thanks for the post.

It encouraged me to google up the GE aviation history wiki page ( https://en.wikipedia.org/wiki/GE_Aviation#History ).

Turns out they really didn't impact WWII much, but they did really impressive things starting later in the 40s:

Development funds were allotted in 1946 for a more powerful version of the same design, the TG-190. This engine finally emerged as the famed General Electric J47, which saw great demand for several military aircraft; a second manufacturing facility near Cincinnati was opened. J47 production ran to 30,000 engines by the time the lines closed down in 1956. Further development of the J47 by Patrick Clarke in 1957 led to the J73, and from there into the much more powerful J79. The J79 was GE's second "hit", leading to a production run of 17,000 in several different countries. The GE and Lockheed team that developed the J79 and the F-104 Mach 2 fighter aircraft received the 1958 Collier Trophy for outstanding technical achievement in aviation. Other successes followed, including the T58, and T64 turboshaft engines, J85 and F404 turbojets.

The TF39 was the first high-bypass turbofan engine to enter production.[10] Entered into the C-5 Galaxy contest in 1964 against similar designs from Curtiss-Wright and Pratt & Whitney, GE's entry was selected as the winner during the final down-select in 1965. This led to a civilian model, the CF6,[11] which was offered for the Lockheed L-1011 and McDonnell Douglas DC-10 projects. Although Lockheed later changed their engine to the Rolls-Royce RB211, the DC-10 continued with the CF6, and this success led to widespread sales on many large aircraft including the Boeing 747.

Producing 47,000 jet engines even before CF6 was on the market is pretty impressive, IMHO.

It's also kind of interesting how Cutiss-Wright was such a huge player in the piston engine era and failed to make the transition to jet engines.

GE got its early lead ( see link above ) by developing ( exhaust-driven ) turbochargers. At one level it seems to be a pretty natural transition to jet engines, on the other hand it seems they botched their earliest efforts in the early 40s but came on strong in the late 40s.
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bigjku
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Re: Best Replacement Engines for the B52

Fri Jul 20, 2018 9:20 pm

Pratt also built the greatest piston engine fighter plane engine of all time in the double wasp.
 
tjh8402
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Re: Best Replacement Engines for the B52

Sat Jul 21, 2018 2:33 am

Revelation wrote:
tjh8402 wrote:
Ozair wrote:

Hopefully not going too off topic but does anyone have some justification for the depth of the USAF/P&W relationship, is there a watershed moment when this relationship cemented?


P&W is the one engine maker that predates the Air Force itself, having built engines for the Army Air Force since before WW2. They also seemed to take the lead on larger jet engines early on. They were the OEM that Boeing selected for the B-52, KC 135, and all the 707 derivatives. GE didn’t really get into the big engine game till the CF6, which is on the VC-25s and C-5M. There have been plenty of other GE powered planes in the Air Force. Plenty of combat planes like F-86, F-4, A-10, B-1, B-2, and F-16 have used GE (GE actually overtook Pratt as the preferred F-16 engine), and the KC-135s are pretty much all CFM powered.

Thanks for the post.

It encouraged me to google up the GE aviation history wiki page ( https://en.wikipedia.org/wiki/GE_Aviation#History ).

Turns out they really didn't impact WWII much, but they did really impressive things starting later in the 40s:

Development funds were allotted in 1946 for a more powerful version of the same design, the TG-190. This engine finally emerged as the famed General Electric J47, which saw great demand for several military aircraft; a second manufacturing facility near Cincinnati was opened. J47 production ran to 30,000 engines by the time the lines closed down in 1956. Further development of the J47 by Patrick Clarke in 1957 led to the J73, and from there into the much more powerful J79. The J79 was GE's second "hit", leading to a production run of 17,000 in several different countries. The GE and Lockheed team that developed the J79 and the F-104 Mach 2 fighter aircraft received the 1958 Collier Trophy for outstanding technical achievement in aviation. Other successes followed, including the T58, and T64 turboshaft engines, J85 and F404 turbojets.

The TF39 was the first high-bypass turbofan engine to enter production.[10] Entered into the C-5 Galaxy contest in 1964 against similar designs from Curtiss-Wright and Pratt & Whitney, GE's entry was selected as the winner during the final down-select in 1965. This led to a civilian model, the CF6,[11] which was offered for the Lockheed L-1011 and McDonnell Douglas DC-10 projects. Although Lockheed later changed their engine to the Rolls-Royce RB211, the DC-10 continued with the CF6, and this success led to widespread sales on many large aircraft including the Boeing 747.

Producing 47,000 jet engines even before CF6 was on the market is pretty impressive, IMHO.

It's also kind of interesting how Cutiss-Wright was such a huge player in the piston engine era and failed to make the transition to jet engines.

GE got its early lead ( see link above ) by developing ( exhaust-driven ) turbochargers. At one level it seems to be a pretty natural transition to jet engines, on the other hand it seems they botched their earliest efforts in the early 40s but came on strong in the late 40s.


GE made a big splash with smaller jets engines (such as in the F86 and F4 that I mentioned, as well as in century fighters), but they didn’t show up on larger transports or airliners till the CF6 debuted. All of the USAFs larger planes up until then were Pratt powered which was what I was noting. It is amazing how Curtis-Wright never survived the transition to jets.
 
FrmrKSEngr
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Re: Best Replacement Engines for the B52

Sat Jul 21, 2018 4:09 am

How about this. Get Paul Allen involved. He has experience getting old jets restored. Fully rebuild the B-52s. The only part you need keep to call an aircraft a restoration as opposed to a replica is the ident plate. That should get it all past congress. Restored planes are not new planes. ;)
 
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kc135topboom
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Re: Best Replacement Engines for the B52

Mon Jul 23, 2018 12:07 am

If the USAF were to reengine the B-52H, they need a cheap engine because they don't have the money for any other option. That said perhaps the best engine choice is the P&W JT-8D-219? You may only need 6 of them as each engine has about 6,000 lbs. more thrust that the TF-33s. The USAF already looked at this engine in the now aborted E-8C reengine program. II believe this is the same engine on the B-707RE, too.
 
Max Q
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Re: Best Replacement Engines for the B52

Wed Jul 25, 2018 2:23 am

kc135topboom wrote:
If the USAF were to reengine the B-52H, they need a cheap engine because they don't have the money for any other option. That said perhaps the best engine choice is the P&W JT-8D-219? You may only need 6 of them as each engine has about 6,000 lbs. more thrust that the TF-33s. The USAF already looked at this engine in the now aborted E-8C reengine program. II believe this is the same engine on the B-707RE, too.



Interesting idea, make it like the B47
it’s six engine predecessor
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mmo
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Re: Best Replacement Engines for the B52

Wed Jul 25, 2018 6:46 am

Just a couple of issues that I see. First, the pneumatic system would require extensive re-engineering since the pneumatic system would need more bleed from 6 low bypass engines. Also, the number 8 engine has the generator so the electrical system would have to be re-designed. In addition, you still might have a problem with Vmca and Vmcg and the current rudder. The H model is right on the edge with its current rudder and engine combo.
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GalaxyFlyer
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Re: Best Replacement Engines for the B52

Wed Jul 25, 2018 4:08 pm

The KC-135R engines were old QF and PAA 707 engines—JT-3D, civil TF-33.

GF
 
rlwynn
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Re: Best Replacement Engines for the B52

Thu Jul 26, 2018 1:25 pm

I tell you. It is going to be an updated TF-33. They do not need anything more.
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mmo
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Re: Best Replacement Engines for the B52

Thu Jul 26, 2018 2:09 pm

rlwynn wrote:
I tell you. It is going to be an updated TF-33. They do not need anything more.

Care to explain the second part of your statement?
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rlwynn
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Re: Best Replacement Engines for the B52

Thu Jul 26, 2018 2:45 pm

The TF-33 already has more than enough power and more would not help. It already has the range needed according to the Air Force. The fuel saving will be minute in the overall fuel use of the Air Force according to them. And new pylons and wing stuctures and everything else associated with new engins are much money. Also the old tech EPM suvivabiliy is much easier to deal with than digital engines.

People sa y P&W cannot produce them anymore as they are long out of production. Well, they are just pieces of metal assembeld together and making new pieces of metal is much faster and cheaper than it was when the engines were first built.

Also it is P&Ws first choice on what to do.
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mmo
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Re: Best Replacement Engines for the B52

Thu Jul 26, 2018 8:29 pm

rlwynn wrote:
The TF-33 already has more than enough power and more would not help. It already has the range needed according to the Air Force. The fuel saving will be minute in the overall fuel use of the Air Force according to them. And new pylons and wing stuctures and everything else associated with new engins are much money. Also the old tech EPM suvivabiliy is much easier to deal with than digital engines.

People sa y P&W cannot produce them anymore as they are long out of production. Well, they are just pieces of metal assembeld together and making new pieces of metal is much faster and cheaper than it was when the engines were first built.

Also it is P&Ws first choice on what to do.


The problem is more than fuel efficiency. Right now the H will have to be retired in 2040 with no mods at all. The mods necessary for the proposed re-engining would allow the Buff to continue flying into the 2050s. The upper wing skin is the limiting factor which would be replaced under the program. In addition, the electrical, pneumatic and hydraulic systems would be updated/upgraded.

PW has stated they did not want to produce new TF-33 engines but rather would like to produce an upgrade kit. https://www.flightglobal.com/news/artic ... en-424327/ However, the current overhaul costs are the real problem. By FY06 that cost had increased to $1.025M for each engine, much more than the studies had anticipated. By 2040, the projected end of the B‑52 service, it could cost more than $7M to overhaul each TF33. The re-engining program would pay for itself based on overhaul costs alone. In addition, some studies have indicated a 45% increase in the range which would reduce tanker dependency.

If you want to read a very good justification for the program, have a look here. http://www.airpowerstrategy.com/2016/11 ... w-engines/
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flyingclrs727
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Re: Best Replacement Engines for the B52

Thu Jul 26, 2018 9:45 pm

GalaxyFlyer wrote:
The KC-135R engines were old QF and PAA 707 engines—JT-3D, civil TF-33.

GF


Don't you mean the KC-135E? The KC-135R's have CFM-56's.
 
GalaxyFlyer
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Re: Best Replacement Engines for the B52

Fri Jul 27, 2018 2:55 am

Ah, yes I do mean the E.

GF
 
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Tugger
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Re: Best Replacement Engines for the B52

Fri Jul 27, 2018 3:58 am

mmo wrote:
In addition, some studies have indicated a 45% increase in the range which would reduce tanker dependency.

Which in turns saves a lot of money AND force demands. The USAF loves those kinds of things.

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Buckeyetech
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Re: Best Replacement Engines for the B52

Fri Jul 27, 2018 12:54 pm

Not sure this has been posted yet. GE will submit two proposals for engine replacements. I know the Air Force won’t do it, but fingers crossed they go with the more advanced Passport engine.

http://www.airforcemag.com/Features/Pag ... ogram.aspx
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LightningZ71
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Re: Best Replacement Engines for the B52

Fri Jul 27, 2018 4:30 pm

Hmm, cf-34-10 or Passport. The CF-34-10 is a few inches larger in outside diameter, so it'll need more extensive mods to the nacell, though will have a significant down-rate to extend life. The Passport may be slightly smaller, so it may fit better, and will also have significantly better SFC than the 34.
 
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trpmb6
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Re: Best Replacement Engines for the B52

Fri Jul 27, 2018 7:20 pm

No matter what there will be extensive work on the pylons and nacelles. Even if they had the same fan diameters you can't just slap the current nacelles on a different engine. The interfaces are all different.

Based on everything I've seen, RollsRoyce still has the best offering.

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