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B-52 & C-17 Engine question for those in the know....


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I That's well over 200,000 total with just four engines. Does the BUFF really need to go from ~ 136,000 pounds of thrust of the eight TF-33s on the "H" to 416,000 pounds with eight CFMs?

Sure it does, then we'd have a Mach 1.5 BUFF....and some RAM and we can got updated help for the B-2 :monkeydance: . Look what Slim Pickens did with one in Dr. Strangelove :wub: .

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That photo shows a GE CF6 being certified for the DC-10, hence the shiny metal, pot-bellied nacelle. I'm not sure if it was the same B-52E that was used for both, but B-52s flew with both the JT9D and the CF6/TF39 at various times.

J

You're exactly right, Jennings. That is the CF6 installation. My bad. That is 0119, the TF-39 testbed. I had forgotten 0019 was bailed to GE for CF6 testing. Thanks for the correction.

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Hey Vindicator,

Didn't mean to steal your thunder. I've had one of those in the "planning" stage for years now but haven't gotten a round to it. My wife keeps swearing she is gonna buy one for me though (the dreaded ROUNDTUIT, from Home Depot)

Good Luck on that, can't wait to see some pics. By the way, are you familiar with the Dale Brown works? The Flight of the Old Dog? I've always wanted to do the EB-52 Megafortress from that series as well. Food for thought!

MAN!!!!! I'm tryin' 2 stop you guys but y'all keep picking my pockets!!! Anyway, you are exactly right as to what my madness is. I have all of dale brown's books and I was thinkin' 'bout tryin' 2 do one of them in 1/144 scale using the revell buff as the starting point for it. By the way, my helo is a bash of the 1/48 academy ch-53 ,the revell ch-53, some hasagawa apache engine exhausts,all the cobra co. detail sets, and some digital camo decals from MAW. I'm going to call it the PAVE HULK when its done. vindicator one

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Somebody posted the CFM-56/7 is rated at 52,000lb. This is not the case... The ones fitted on Ryanair's 737-800 are rated at 26,000lb each (some operaters go in excess of 27K)....so it's easy to see where the confusion comes from (26x2). The most powerfull CFM-56 is the -5C, as fitted to the A340-300. It's basically the same engine as the -5A and -5B as found on the A320 family with a longer nacelle. The -7 is the most recent verion, but the fan diameter is smaller, as it was designed for the B737NG with it's lower ground clearance. Being more recent, it also uses fewer wide cord fan blades (24 in total).

Hope this helps.

Best regards,

Guillaume

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Thanks Guillaume,

My apologies, that would be me quoting from a misinformed or typo-ed source. You are indeed correct that the CFM56-5C is the most powerfully rated of the bunch, at 34,000 lbs ea (now quoting from the CFM website). At those numbers, if the 52 were re-engined using them, the plane would still have the same amount of thrust as it does with the TF-33s, would weigh less, have half the require engine maintenance, be more fuel efficient, and quieter, and have extended range. These engines have been available for fifteen years now, so what kind of savings and performance improvements could have been realized during that time? The bean counters will never admit to any but it's pretty obvious that benefits would have been significant, weighed against the cost to maintain, rebuild/replace TF-33s and continuing to fly the planes with eight old engines verses four new, whether it was the CFMs or something else.

Hey Vindicator One, drop a line. I'd like to hear more about your PAVE HULK! Sounds really cool and right up the "What-If" alley I normally cruise.

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Thanks Guillaume,

My apologies, that would be me quoting from a misinformed or typo-ed source. You are indeed correct that the CFM56-5C is the most powerfully rated of the bunch, at 34,000 lbs ea (now quoting from the CFM website). At those numbers, if the 52 were re-engined using them, the plane would still have the same amount of thrust as it does with the TF-33s, would weigh less, have half the require engine maintenance, be more fuel efficient, and quieter, and have extended range. These engines have been available for fifteen years now, so what kind of savings and performance improvements could have been realized during that time? The bean counters will never admit to any but it's pretty obvious that benefits would have been significant, weighed against the cost to maintain, rebuild/replace TF-33s and continuing to fly the planes with eight old engines verses four new, whether it was the CFMs or something else.

Hey Vindicator One, drop a line. I'd like to hear more about your PAVE HULK! Sounds really cool and right up the "What-If" alley I normally cruise.

sure thing, just let me know what ya wanna know about my build and I'll give ya all the details on it. we may see eye ta' eye on this modeling thing b'coz building models as they are str-8 out of the box sometimes loses its luster 2 me. you should see my super bug that I am doing also. another what-if build of mine is in the b-1b builders thread, just look for vindicator one in it.

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  • 12 years later...

I have been following this discussion, and I wanted to share the attached scan of a medium format negative in my collection of B-52E 56-0636 with the JT9D engine installed. I contacted someone at PW to see if they might have other images of this airplane and flight test for my research.

 

Mike Wilson

B-52E 56-0636 while fitted to test the JT9D engine [MWilson Colo].jpg

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Posted (edited)

Mike, I recently saw a photo of this aircraft in flight, possibly on one of those "This Day in Aviation History " sites.  Ah! Wiki has one. The BUFF, though bailed back to Boeing for the engine fitment and test, still has its 96th BW badge on the nose. I believe that the photo bird in the foreground is a Canberra?

Edited by Dutch
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Cool photo, Mike!

 

I recently read that the reason they’re going with 8 Rolls Royce engines instead of four big fans is due to a lack of rudder authority after an engine failure. This will also avoid the problem of having to do major redesigns of the cockpit, wings, and other systems for four engines.
 

Ben

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Hello Dutch,

I have seen the images online, but none really show the pylon modification to adapt the JT9D engine. That is one of the checkbox items I'm hoping my PW POC can provide. My intent is to build a 1/144 version of this specific B-52. I have four 1/144th scale JT9D resin engines, etc...

Ben the USAF cites cost as the primary justification for retaining four engines. As you noted, it would be super expensive to rework the cockpit, wing and the associate plumbing, etc...

 

Mike Wilson

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2 hours ago, Ben Brown said:

Cool photo, Mike!

 

I recently read that the reason they’re going with 8 Rolls Royce engines instead of four big fans is due to a lack of rudder authority after an engine failure. This will also avoid the problem of having to do major redesigns of the cockpit, wings, and other systems for four engines.
 

Ben

Ben,

Yes. It is going to be expensive enough to convert the old manual engine controls & displays to digital controls & displays that they decided to save money by not having to redesign the pylons.  Hence they stipulated that the new engines fit the same size and placement specs for the old TF33s.  A literal one-for-one replacement.   I guess the tab for the pylon redesign was a deal breaker. 

 

1 hour ago, mikeavphoto said:

Hello Dutch,

I have seen the images online, but none really show the pylon modification to adapt the JT9D engine. That is one of the checkbox items I'm hoping my PW POC can provide. My intent is to build a 1/144 version of this specific B-52. I have four 1/144th scale JT9D resin engines, etc...

Ben the USAF cites cost as the primary justification for retaining four engines. As you noted, it would be super expensive to rework the cockpit, wing and the associate plumbing, etc...

 

Mike Wilson

Mike,

Right!  I hope that he can provide factory drawings.  Fingers crossed!

 

K/r,

Dutch

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One thing I always wondered about this topic is if the big high bypass turbofans are suitable for the B-52 in combat. Is my understanding correct that the draw back to a High bypass turbo fan is that is takes longer to spool up? ... so if they have to speed up to bug out, a smaller engine can spool up quicker and make the plane more responsive. 

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The B-52 is a very large, heavy bomber.  In combat, it’s going to depend on its countermeasures.  I don’t see the spool up time of the engines being a factor in avoiding attack from a modern fighter or missile.

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I can tell you this; the new engines went to the test cells about six weeks ago (no later than one month ago).  These are prototypes, and will probably see a few changes here and there as they are developed. Should be all systems go this time next year. They have only just begun to tool them up, and that alone can take a year or more. Much of the in house equipment is up to the task of manufacturing them, but there is still a lot of new machines needed. 

 

Jet engines; unlike others are a low volume production thing. I doubt they'll set it up for  more than 72 units a year. I know who to ask, and will. Another issue is getting machine time while stealing it from other projects. That place is pretty big, but most of the space is being used for non military projects (where the big money is).  I suspect it will be built in the old TF41 area as it's big enough. The TF56 is still the big money maker, so they won't get in their way

gary

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