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Chances Of A Re-Engined 757?   
User currently offlineCoronado From United States of America, joined Jun 1999, 1170 posts, RR: 2
Posted (3 years 7 months 3 weeks 2 days 1 hour ago) and read 8873 times:
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As B757's get removed from mainline pax fleets over coming years what are possibilities that they get taken over by the FEDEX and UPS's of the world and re-engined with these new 15% fuel saving engines? This would take us back to the days of all the DC8 re-enginning programs. These are probably the only two companies that would consider such programs. Does the 757's existing landing gear provide enough room for the new high BPR engines being developed to be slung below those big wings?


The Original Coronado: First CV jet flights RG CV 990 July 1965; DL CV 880 July 1965; Spantax CV990 Feb 1973
24 replies: All unread, jump to last
 
User currently offlinekeesje From , joined Dec 1969, posts, RR:
Reply 1, posted (3 years 7 months 3 weeks 2 days 1 hour ago) and read 8825 times:

Quoting Coronado (Thread starter):
Does the 757's existing landing gear provide enough room for the new high BPR engines being developed to be slung below those big wings?

I think there enough room under the wings but the 757 wings are (relatively) small. I wonder what would be the right 37-43 k lbs engines though..


User currently offlinedl767captain From United States of America, joined Mar 2007, 2539 posts, RR: 0
Reply 2, posted (3 years 7 months 3 weeks 2 days 1 hour ago) and read 8690 times:

Would the cost of purchasing new engines be wroth it though? I think you would have to save a lot of fuel to make purchasing two new engines for a 757. The other problem is that the airframes themselves are getting old. Sure you can keep them going but again it comes down to whether it's worth paying for heavy maintenance on older 757s (like has been done on the DL DC-9s) to make two new engines worth it.

User currently offlineBureaucromancer From Canada, joined Feb 2010, 165 posts, RR: 0
Reply 3, posted (3 years 7 months 3 weeks 2 days 1 hour ago) and read 8673 times:

Without digging up the actual numbers I suspect that while this wouldn't be any more technically complicated than the old DC8/707 re-engining programs the benefit would be less between the more advanced base engine and the efficiencies of twin jets.

User currently onlineStitch From United States of America, joined Jul 2005, 30609 posts, RR: 84
Reply 4, posted (3 years 7 months 3 weeks 2 days ago) and read 8633 times:
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Quoting Bureaucromancer (Reply 3):
Without digging up the actual numbers I suspect that while this wouldn't be any more technically complicated than the old DC8/707 re-engining programs the benefit would be less between the more advanced base engine and the efficiencies of twin jets.

Agreed.

Unless fuel really spiked and the freight companies can no longer pass it on via fuel surcharges, the economics might not pan out over the long run.


User currently offlineGarpd From UK - Scotland, joined Aug 2005, 2629 posts, RR: 4
Reply 5, posted (3 years 7 months 3 weeks 2 days ago) and read 8618 times:

Would re-engining the 757 be worth it?

The DC-8 was a different case, engine technology had come on leaps and bound since it launched. From turbojets to turbofans. There was a significant reduction in fuel burn and increase in range (and MTOW I believe).

The 757 might be long in the tooth, but the RB211 is still a good, reliable and efficient engine. Strapping new engines to it might not do anything worthwhile.



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User currently offlinecuban8 From Kiribati, joined Sep 2009, 269 posts, RR: 0
Reply 6, posted (3 years 7 months 3 weeks 2 days ago) and read 8561 times:

Even though the B787 will have more range and payload, wouldn't it be more or less a more capable B757 NEO? Does anybody know if the future A321 NEO will ever compete on certain routes with the B788?

User currently offlineaquila3 From Italy, joined Nov 2010, 251 posts, RR: 0
Reply 7, posted (3 years 7 months 3 weeks 2 days ago) and read 8442 times:

Quoting cuban8 (Reply 6):
Even though the B787 will have more range and payload, wouldn't it be more or less a more capable B757 NEO? Does anybody know if the future A321 NEO will ever compete on certain routes with the B788?

I do not know if the A320Neo will compete on the 787 field. Probably not. But it WILL by sure on the 757one.



chi vola vale chi vale vola chi non vola è un vile
User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 8, posted (3 years 7 months 3 weeks 1 day 18 hours ago) and read 8022 times:

Quoting Coronado (Thread starter):

As B757's get removed from mainline pax fleets over coming years what are possibilities that they get taken over by the FEDEX and UPS's of the world and re-engined with these new 15% fuel saving engines?

What new 15% fuel savings engines? The PW1000 and Leap-X aren't large enough, and there's no way any engine OEM is going to make any money designing an engine just for a 757 retrofit.

Tom.


User currently offlineBMI727 From United States of America, joined Feb 2009, 15719 posts, RR: 26
Reply 9, posted (3 years 7 months 3 weeks 1 day 17 hours ago) and read 8006 times:

Quoting keesje (Reply 1):
I wonder what would be the right 37-43 k lbs engines though..

There isn't one. PW1000G and Leap-X are too small and GEnx is too big. Having to develop an engine to refurbish 757s would kill the business case. Using off the shelf engines is one thing, but I can't imagine a modification program recouping development costs.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlinePM From Germany, joined Feb 2005, 6870 posts, RR: 63
Reply 10, posted (3 years 7 months 3 weeks 1 day 17 hours ago) and read 7914 times:

I suppose the Trent 500 would be too big?

User currently offlineBMI727 From United States of America, joined Feb 2009, 15719 posts, RR: 26
Reply 11, posted (3 years 7 months 3 weeks 1 day 17 hours ago) and read 7902 times:

Quoting PM (Reply 10):

I suppose the Trent 500 would be too big?

Yes. Compared to the current engines it will give an extra 10,000 lbs of thrust and weighs 3000 lbs more than the RB211s.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlinePM From Germany, joined Feb 2005, 6870 posts, RR: 63
Reply 12, posted (3 years 7 months 3 weeks 1 day 15 hours ago) and read 7802 times:

Quoting BMI727 (Reply 11):
Yes. Compared to the current engines it will give an extra 10,000 lbs of thrust and weighs 3000 lbs more than the RB211s.

Yeah. And it would just blow up anyway...  


User currently offlineAirbusA6 From United Kingdom, joined Apr 2005, 2011 posts, RR: 0
Reply 13, posted (3 years 7 months 3 weeks 1 day 13 hours ago) and read 7666 times:

A Trent 500 powered 757 would certainly be powerful, and even more of a rocket on take off! I'll take one as my private jet 


it's the bus to stansted (now renamed national express a4 to ruin my username)
User currently offlineparapente From United Kingdom, joined Mar 2006, 1548 posts, RR: 10
Reply 14, posted (3 years 7 months 3 weeks 1 day 12 hours ago) and read 7592 times:

The 757 will become (is even) a great "trucker".With the NEO announced and probably the same shortly from Boeing it will, by mid decade, disapear very quickly indeed. It's had a great run,sold a 1,000 copies and wil be well remembered.I feel lucky to have flown on one of the very last BA 757 legs from Spain late this summer. RIP

User currently offlineGarpd From UK - Scotland, joined Aug 2005, 2629 posts, RR: 4
Reply 15, posted (3 years 7 months 3 weeks 1 day 10 hours ago) and read 7490 times:

Quoting parapente (Reply 14):
it will, by mid decade, disapear very quickly indeed

Doubtfull. The NEO will only EIS in 2015 if all goes to plan and it's doubtfull the A320 and A321 will EIS at the same time.
I bet they'll EIS the A320 first. Then the A321.
It will take 10 years or so after that before enough A321NEO's are in service to free up non NEO A321s for convertion and get even close to the number of 757s in service.

I warrant that the 757 will most likely follow it's sister 727's footsteps and continue to fly for many, many years to come.

[Edited 2010-12-10 05:00:08]


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User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12128 posts, RR: 51
Reply 16, posted (3 years 7 months 3 weeks 1 day 8 hours ago) and read 7099 times:

Quoting Garpd (Reply 15):
Garpd

Per the announcement from Airbus on the EIS of the A-32X-NEO;

A-320NEO = 2016
A-321NEO = 2017
A-319NEO = 2018

Flight testing and STC for each model will be about 1 year earlier than the EIS.


User currently offlineAADC10 From United States of America, joined Nov 2004, 2073 posts, RR: 0
Reply 17, posted (3 years 7 months 3 weeks 1 day 3 hours ago) and read 4650 times:

Quoting Coronado (Thread starter):
As B757's get removed from mainline pax fleets over coming years what are possibilities that they get taken over by the FEDEX and UPS's of the world and re-engined with these new 15% fuel saving engines? This would take us back to the days of all the DC8 re-enginning programs.

The chances of a re-engined 757 are close to zero. The cost to benefit ratio would not be good enough to make it worthwhile. The re-engined DC8s were a comparatively minor change, essentially installing a high bypass turbofan to replace an earlier generation turbofan. Improving fuel burn slightly is not enough to make it worthwhile, especially for cargo aircraft that spend more of their time on the ground than passenger airliners.

Quoting BMI727 (Reply 9):
PW1000G and Leap-X are too small and GEnx is too big.

There are other reasons why they would be impractical. It is unclear if the PW1000G or Leap-X could be scaled up to power a 757 with any gains in efficiency and again fuel efficiency is less important in cargo aircraft. The GEnx is a bleedless engine and the 757 could probably not be reconfigured to operate with that type.


User currently offlinePPVRA From Brazil, joined Nov 2004, 8942 posts, RR: 40
Reply 18, posted (3 years 7 months 3 weeks 1 day 3 hours ago) and read 4391 times:

In any case, I don't think anyone would be looking at re-engining the 757 for at least another 10-15 years. Lot's can happen between now and then. The only question is whether there would be enough 757s with enough life left in them to justify a re-engining program.


"If goods do not cross borders, soldiers will" - Frederic Bastiat
User currently offlineB777LRF From Luxembourg, joined Nov 2008, 1302 posts, RR: 3
Reply 19, posted (3 years 7 months 3 weeks 1 day 2 hours ago) and read 4257 times:

There are exactly two chances of that happening: Fat and none. Pick preferred option at your leisure.


From receips and radials over straight pipes to big fans - been there, done that, got the hearing defects to prove
User currently offlineBMI727 From United States of America, joined Feb 2009, 15719 posts, RR: 26
Reply 20, posted (3 years 7 months 3 weeks 1 day ago) and read 3674 times:

Quoting AADC10 (Reply 17):
It is unclear if the PW1000G or Leap-X could be scaled up to power a 757 with any gains in efficiency and again fuel efficiency is less important in cargo aircraft.

That' falls under too big or too small, I should have clarified.

Quoting AADC10 (Reply 17):
The GEnx is a bleedless engine and the 757 could probably not be reconfigured to operate with that type.

The version going on the 747 will have bleed air. The reason that GEnx bleed would be an issue for the 757 is a business problem, and probably not a technical one.



Why do Aerospace Engineering students have to turn things in on time?
User currently offlineSchorschNG From Germany, joined Sep 2010, 500 posts, RR: 0
Reply 21, posted (3 years 7 months 3 weeks 12 hours ago) and read 3455 times:

The majority of B757 have been delivered in the 1990ies, so retirement is likely to spike in the 2015 region.
If a good replacement is available before lifetime is over, they'll go to cargo carriers. See DC10/MD11.
If no real replacement is available and the aircraft does the job, they are flown to death.

The A321 can do 80% of all B757-200 missions today, with NEO probably 90 to 95%.



From a structural standpoint, passengers are the worst possible payload. [Michael Chun-Yung Niu]
User currently onlineSEPilot From United States of America, joined Dec 2006, 6834 posts, RR: 46
Reply 22, posted (3 years 7 months 3 weeks 7 hours ago) and read 3259 times:

The DC-8 was fortunate in that the CFM56 existed and was a good fit. There is no engine that is a good fit for the 757, they are all too big or too small. And there are no aircraft under development that will require a 757 sized engine either, so the chances of a re-engining program are exactly zero. Nobody is going to put upwards of a billion dollars in developing an engine for an orphan, let alone the costs of designing and certifying the conversion.


The problem with making things foolproof is that fools are so doggone ingenious...Dan Keebler
User currently offlineSchorschNG From Germany, joined Sep 2010, 500 posts, RR: 0
Reply 23, posted (3 years 7 months 3 weeks 6 hours ago) and read 3161 times:

Quoting SEPilot (Reply 22):
The DC-8 was fortunate in that the CFM56 existed and was a good fit.

Not too surprising, as the CFM56 was designed as plug-in replacement for the B707-derived KC135s.
But the DC-8 is probably a one-time event, as the step change in efficiency was so great, the engine life was greatly increased, noise dramatically reduced and the cost easily re-earned.
An only marginally more efficient engine wouldn't probably make no sense.
I think the only current re-engining program is the C-5B update.



From a structural standpoint, passengers are the worst possible payload. [Michael Chun-Yung Niu]
User currently offlinemilesrich From United States of America, joined Jul 2003, 1992 posts, RR: 6
Reply 24, posted (3 years 7 months 3 weeks 6 hours ago) and read 3112 times:

Quoting Garpd (Reply 5):
Would re-engining the 757 be worth it?

The DC-8 was a different case, engine technology had come on leaps and bound since it launched. From turbojets to turbofans. There was a significant reduction in fuel burn and increase in range (and MTOW I believe).
Quoting AADC10 (Reply 17):
The chances of a re-engined 757 are close to zero. The cost to benefit ratio would not be good enough to make it worthwhile. The re-engined DC8s were a comparatively minor change, essentially installing a high bypass turbofan to replace an earlier generation turbofan. Improving fuel burn slightly is not enough to make it worthwhile, especially for cargo aircraft that spend more of their time on the ground than passenger airliners.
Quoting SEPilot (Reply 22):
The DC-8 was fortunate in that the CFM56 existed and was a good fit. There is no engine that is a good fit for the 757, they are all too big or too small. And there are no aircraft under development that will require a 757 sized engine either, so the chances of a re-engining program are exactly zero. Nobody is going to put upwards of a billion dollars in developing an engine for an orphan, let alone the costs of designing and certifying the conversion.
Quoting SchorschNG (Reply 23):
Not too surprising, as the CFM56 was designed as plug-in replacement for the B707-derived KC135s.
But the DC-8 is probably a one-time event, as the step change in efficiency was so great, the engine life was greatly increased, noise dramatically reduced and the cost easily re-earned.
An only marginally more efficient engine wouldn't probably make no sense.
I think the only current re-engining program is the C-5B update.

The quoted text above says it all. First of all, the DC-8-71/3 conversion replaced relatively inefficient first generation low bypass turbofan engines (JT-3D), not turbojet JT-4's, with high bypass CFM-56 turbofan engines. This was a real leap in technology. Today, 737NG's are powered by the latest versions of the CFM-56, so in effect, the DC-8 conversion swapped 1961 technology for technology still in use today on new aircraft. Secondly, the conversion, especially of the -61's into -71's provided increased range. The DC-8 fuselage also has a fair amount more capacity than the 757, so there was another good reason to adopt it by the cargo carriers. Also, quite a few of the -71's, 42 to be exact, were converted by the passenger carriers, UA and DL, before they were sold off to the cargo carriers in the late 80's/early 90's. (I know they sold and then leased back, with Delta retiring theirs and turning them over to UPS before United retired all of their fleet). Thirdly, the DC-8 probably was a bit more stout in terms of structure, and therefore, had a longer service life. The other issue is that, at least in the USA, the carriers that fly the 757, (CO, US, DL, AA, and UA) all except US, have fairly good sized fleets and no aircraft on order to really replace the 757, and the four carriers also have sizable 767 fleets which allow them to use the same flight crews because of the rating and similar cockpit layouts. Right now, the 757 is the best aircraft for long thin over water routes. Therefore, I do not think we will see these airlines getting rid of many of their 757's until they are economically used up, perhaps requiring D-checks or other very intense and expensive maintenance. As has been pointed out, saving 15% in fuel would most likely not justify the costs involved in re-engining, requiring a possible strengthening of the wing etc. And lastly, with the slow down in the world economy and the lingering debt crisis in many countries, it is really doubtful that increased capacity will be needed in the short to medium term.


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