PPRuNe Forums


Tech Log The very best in practical technical discussion on the web

Reply
 
Thread Tools Search this Thread
Old 14th Jan 2018, 10:51   #1 (permalink)
Thread Starter
 
Join Date: Sep 2013
Location: France
Age: 41
Posts: 14
Hello everyone,

It's been a while since I've been able to return to this beautiful community of professionals in a field that I love, aviation and aeronautics, even if unfortunately I could not make my profession of it ... Oh and with a little delay I wish you all a happy new year 2018. Moreover, I beg my English-speaking readers to apologize for any clumsy aeronautic formulations in english because I am French-speaker.

The Leap engine is about to succeed the CFM 56 I think in the coming decade. So I'm wondering when the production line of the latter engine will definitely be stopped. It seems to me that today it remain only the -5B and -7B variants on the 737 NG and the A320 ceo . I hypothesize that the production of the CFM 56 will definitely be stopped with the complete replacement of the 737NG and A320 ceo fleets through the world ... Could it be possible however for these aircrafts to be updated with Leap engines?

I still find quite limiting for customers of the 737 MAX family the unique choice of the Leap 1B engine, even if the PW1000G GTF still seems to know some sins of youth ... Why have imposed this unique engine?

In the impatient expectation of your kind answers.
Yan104 is offline   Reply With Quote
Old 14th Jan 2018, 13:02   #2 (permalink)
 
Join Date: Aug 2009
Location: Either down at the pointy end or up in the crew rest...
Posts: 492
Well, take a close look at a LEAP-1B, and tell me that you don't find it in any way similar to a CFM56

Its still made by CFM, comes in equivalent thrust ratings to the CFM56-7B, and is probably closer to the -7B than the -3B is to the 7B
STBYRUD is offline   Reply With Quote
Old 14th Jan 2018, 13:54   #3 (permalink)
 
Join Date: Apr 2008
Location: Nearer home than before!
Posts: 351
The 7BE has been in production since 2014. The wing is hte same, more or less, so re-engining is perfectly possible, however, with the life expectancy of most CFM engines being very good, the real question is will the number of -NGs going to the boneyard provide enough to keep the new build NGs in the air for the next 30 years. Probably more than likely.

The reason for the single supplier is cost saving for Boeing. One thing that really blows costs out of proportion, is too many options and choices. Airbus must be rueing the day they gave in on that with the A380....
RVF750 is offline   Reply With Quote
Old 14th Jan 2018, 14:08   #4 (permalink)
 
Join Date: Aug 2016
Location: Brussels
Posts: 9
The Leap 1B engine is also heavier by a few hundred kg's compared to the CFM56, so I don't think a "simple" re-engining is possible. They had to increase strength of some structural components.
Themax23 is offline   Reply With Quote
Old 14th Jan 2018, 19:33   #5 (permalink)
 
Join Date: Jul 2013
Location: Everett, WA
Age: 62
Posts: 1,450
The CFM56-7B will remain in production as long as Boeing is still building P-8s. It would cost a not so small fortune to recertify the P-8 with the Leap - too much to be justified for a relatively small production run.
I don't expect to see the NG re-engine with the Leap. The integration of the engine with the airframe makes it cost prohibitive (this is true for most modern airliners).
tdracer is offline   Reply With Quote
Old 15th Jan 2018, 14:48   #6 (permalink)
Thread Starter
 
Join Date: Sep 2013
Location: France
Age: 41
Posts: 14
Hello everyone,

I thank you for your participation. I answer each of you point by point by broadening the debate:

Quote:
STBYRUD said

Well, take a close look at a LEAP-1B, and tell me that you don't find it in any way similar to a CFM56

Its still made by CFM, comes in equivalent thrust ratings to the CFM56-7B, and is probably closer to the -7B than the -3B is to the 7B
First of all STBYRUD your answer seems to me a little off topic, I did not speak of comparison between the performance of the CFM56 and the Leap, but the moment when will be decided the stopping of the chain of the CFM56, and the total replacement of this engine by LEAP.
But even so, I doubt that motorists would commit millions of dollars and a program of 5 years of research and development (is the rule for any new engine in this sector) to produce machines without real progress for airlines customers both in terms of consumption performance and engine thrust ... The standard for current engines is a dillution rate of 9 when at the time of the first CFM56 when reaching the 7 was a feat !!. ..And according to Safran Engines, the CFM56-3 thrust range was 82/105 kn compared to the 124.5kn of Leap 1B !
I think in fact that the current goal of any motorist is to lighten up the entire reactor by using more and more composite or other alloys conferring endurance and strength especially for blades of compressors and turbine , and the resistance of the combustion chamber, to space maintenance cycles, and to refine more and more the specific consumption by improving the dillution rate to give more autonomy to the aircraft equipped.

Quote:
RVF750

The 7BE has been in production since 2014. The wing is hte same, more or less, so re-engining is perfectly possible, however, with the life expectancy of most CFM engines being very good, the real question is will the number of -NGs going to the boneyard provide enough to keep the new build NGs in the air for the next 30 years. Probably more than likely.
I think that a remotorization is not directly related to the type of wing but rather with the ancillary equipment accompanying the operation of the reactor: the kerosene circuit is it the same, the pumps are they the same, are the various accessories out of the engine block the same for a CFM56 as for a LEAP? If not, is their replacement expensive in addition to installing the new engine?
On the other hand, I would be interested to know the elements that determine the maximum life of a reactor in general, and different variants of the CFM56 more precisely (if possible)? Which elements of the reactor wear out the most and which others are so vital that it is necessary to replace it with a new engine? For how many hours of flight are the current CFM56-7Bs expected compared to LEAP?
Do not the conditions of use of an airplane affect the life of a reactor: for example low-cost airlines that have the practice of using their aircraft at the maximum of the number of hours they can do per day, and therefore the multiplication of takeoff cycles where the engines give their full power, does it not reduce more the life of the reactors that equip them than in other companies generally state?
The climatic environment in which reactors commonly operate can also, in my opinion, affect the overall service life of a reactor: if, for example, it is in a salty climate, the wear of the parts will be greater than for an aircraft operating in mountainous areas do not you think?

Quote:
RVF750

The reason for the single supplier is cost saving for Boeing. One thing that really blows costs out of proportion, is too many options and choices. Airbus must be rueing the day they gave in on that with the A380...
Regarding the variety of engines proposed by an aircraft manufacturer, I think that opposite to you it gives the choice to companies to refine the performance of their aircraft in terms of operating costs and autonomy, and to play competition between engine manufacturers in terms of the performance of engines that each offers in terms of maintenance cost, endurance, and adaptation to noise and ecological standards. I think in fact that it is not up to the aircraft manufacturer to impose a particular type of engine, unless it has difficulties of integration with other competing models. It is true that for the Leap the nacelle of 737 MAX has been modified, but I do not know if it really is what dictates the only choice of this engine.

And finally another question to come back to our subject, is the production line of an engine stops automatically with that of an airplane (so with the chains of the A320 ceo and B737NG), or is it maintained for the used aircraft market for spare parts? Since planes are generally intended for a maximum lifespan of 40 years, the 737NG and A320 ceo will not leave the scene until 2030, is to say that the CFM56 continue to exist until that date?

Last edited by Yan104; 15th Jan 2018 at 15:17.
Yan104 is offline   Reply With Quote
Old 17th Jan 2018, 15:40   #7 (permalink)
 
Join Date: Feb 2013
Location: 60 north
Age: 53
Posts: 249
The production of the CFM 56 will be on for the next 15 years for sure.
With that many air-frames needing new engines before frame is scraped.
I never fly aircraft older then 10 years, and every so often I see an " old " one with one new engine.

The rate of production is hard to tell this early.

Are You asking because You work for the Manufacturer"
BluSdUp is offline   Reply With Quote
Old 17th Jan 2018, 22:13   #8 (permalink)
 
Join Date: Jul 2013
Location: Everett, WA
Age: 62
Posts: 1,450
When the new aircraft market goes away, the engine will go out of production soon after. The engine manufacturer will calculate how many spares will be needed to support the fleet through the expected retirement, build that many engines, then shutdown everything aside from the normal consumable spares (things like turbine blades and 'life limited' parts). It's simply not cost effective to maintain a production line that's only making a few spare engines. And, even a huge fleet of engines such as the CFM56-5 or -7 won't need that many additional spares - as aircraft get retired those engines are often overhauled and put back into the spares pool. Look at something like the JT8D - something like 10,000 manufactured with many still flying around, but Pratt hasn't built a new JT8D in nearly 20 years.
That being said, the CFM56 is still scheduled to go on new build aircraft for several more years - it won't be going OOP anytime soon.
tdracer is offline   Reply With Quote
Old 17th Jan 2018, 23:32   #9 (permalink)
 
Join Date: May 2015
Location: Inverness
Posts: 910
Quick comment with regards to the comment of being able to re-engine a NG with the Leap...

To fit it on the Max they had to raise the nose gear by 8 inches to accommodate the larger diameter fan and then added jiggery magic with the spoilers to maintain the landing attitude etc and that is the few highlights of what is different to connect the larger engine.

I can't see it happening.. the CFM in it's current guise is a very reliable economic engine and while the leap is more economic I can't see fuel getting high enough in price to cover those mods if it is even possible.. certification costs etc would be wildly prohibitive.
TangoAlphad is online now   Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT. The time now is 10:11.


1996-2012 The Professional Pilots Rumour Network

SEO by vBSEO 3.6.1