Leeham News and Analysis
There's more to real news than a news release.
There's more to real news than a news release.
Leeham News and Analysis
- Boeing unlikely to meet FAA’s 90-day deadline for new safety program April 18, 2024
- Focus on quality not slowing innovation, says GKN April 18, 2024
- Boeing defends 787, 777 against whistleblower charges April 17, 2024
- Dissecting Boeing CEO’s statement next new airplane will cost $50bn April 15, 2024
- Bjorn’s Corner: New engine development. Part 3. Propulsive efficiency April 12, 2024
Odds and Ends: CFM progress on LEAP-1B; advancing 737 MAX EIS, Bombardier and more
CFM on LEAP-1B: Aviation Week has this snippet about progress being made on the LEAP-1B. Contained within is a small reference to Boeing advancing EIS of the 737 MAX, which Boeing said was its desire from the get-go. For those who may have forgotten, EIS is 4Q2017. We understand Boeing would like to bring this forward to 1Q or 2Q2017.
Bombardier on CSeries: the company has been urged to deeply discount the CSeries to boost sales. Ain’t gonna happen, the CEO says.
Helping COMAC win certification: Bombardier says it will help COMAC win certification for the C919 outside China. But we’re still waiting to see what BBD gets out of the deal.
Inerting Boeing 757F fuel tanks: Or not.
Obviously Bombardier took a very different approach on the CSeries than Boeing on the 787. Boeing had a huge backlog from the start, but those airplanes were sold below cost. I always knew that BBD would not take this route because it had nearly put them into bankruptcy back in 2002. They realized at the time what Beaudoin says in the article: they had sold too many airplanes to too few customers, and with an unrealistic discount.
Bombardier had something to prove in those days and they wanted to sell as many airplanes as they could in order to create a big impact. But the experience teach them a lesson, just like the 787 debacle also teach Boeing a lesson. I understood BBD’s strategy from the start because I had read extensively on the issues that brought them into deep financial troubles ten years ago. And that might explain why I am so critical of Boeing some times.
But there is more than just pricing considerations in their approach. They knew early on that they had to avoid any serious delays with the program because of all the bad publicity generated by the problems on the A380 and 787. In order to mitigate the risks they took unprecedented measures to avoid potential roadblocks at any given time in the development of the aircraft. So far it looks like they have succeeded.
If there are no serious delays and the CSeries makes its first flight on time, then the orders should soon start to come in at a pace more in tune with the expected performances of this new aircraft. And if they stick to their policy on pricing the program should reach break-even early on.
the problem with CSeries is there are serious delays. Compare that program to A350, which was also advertised as a 2013 airplane. Airbus is at least making progress on assembly of it’s first airplanes, BBD… not so much. BBD only started their iron bird at the end of May this year… Airbus did that in December 2010. I do not know how BBD and Beaudoin can sit there and still claim “we’re on time” when the facts stare everyone in the face. For them to be “on time” they would have had to have started to build the first airplane already for static test, which they have not. Much less start building the first flight test airplane. Just compare with A350, which is now a mid 2014 AT LEAST program. BBD is just flat out lying. It is amazing that no reporters or analysts have challenged them on this farce.
Looks like they are about 6 months late. Anything up to 12 months will probably be rated as a success by everyone else than Powerpoint-Rangers and KPI-Lemmings.
Fully agree. Moreover, since the 787, 747-8 performance misses and 787, 747-8 and A380 schedule misses, customers are now asking for steep compensation clauses. I think BBD is wise to not pursue the ‘Wall Street darling’ approach with hundreds of orders ‘secured’ early. How many ‘analysts’ dubbed the 787 the ‘most successful commercial aircraft program in history’?
Good news from CFMI on the Leap-1B engine. Design freeze this September is faster than I had thought it would be. I hope Boeing can accelerate the MAX program by about 6-9 months. That would put the MAX EIS about 12-15 months behind the (currently scheduled) NEO EIS.
I guess the 1B has the advantage of being the row, benefitting from the hard work on earlier versions. I think a core shrink is a phantom. CFMI wants to have one core for the 3 engines that are all in the same thrust class. A 10% core shrink for a sofar moderately successful aircraft in a market where thrust requirements will rather grow then decline is a bad investment. The dedicated 1B features will likely be the fan, relocation of accessories, attachment points etc.
I always thought that the 1B would be a very costly programme for CFMI. Normally when a manufacturer develops a new engine it is expected that it will find many applications. That is where the ROI can be found. But in this case it is a dedicated engine that will probably never have another customer but Boeing.
The problem with the 1B is that it is not a real derivative where we see a basic standard design that can be derated for various applications. If the 737 MAX is very successful CFMI could be able to make a profit. And if Airbus had only the 1A to offer it would probably be successful. But with the P&W GTF on the horizon the chances that CFMI will see its money back are slim; because whatever sales they can secure come with a heavy discount due to the unprecedented competition.
TG3 is NOT design feeeze… whatever the article says. TG3 is the end of the concept phase and while the performance at TG3 is a good guidance for the engine to be (usually being a few % off, to be fixed later), the design of pretty much everything is so early that you only have a rough idea of what the structural problems will be.
And problems there will be, nothing is good enough design wise out of the concept design box. There remains LOADS of work before components take their final form, including the turbomachinery. All CFM has at this stage is a good idea of how things will look.
Design freeze can be said to happen when the detailed design phase starts, which is scheduled for Q2 2013 (judging from when TG3 is planned, I’d say that this means late Q2).
It is in the preliminary phase that you find most of your unknown unknowns as you start working more and more details into the design of your components. I’d say that until the preliminary phase is done the engine weight will not be definite, if that gives you some hint of the general state. And I promise you they will be short on life for at least two three major components/frames well into the detailed phase.
And this is all normal, it usually looks like this, so no reason to be alarmed or anything. But definitely not any reason either to be looking forward to what they call design freeze, because it really isn’t.
When Beaudoin says that the CSeries is on time he means that the airplane should make its maiden flight by the end of 2012, as they had said initially at Farnborough in 2008 when they launched the programme.
Because they realized early on that the Dreamliner development schedule was not realistic for an aircraft of that complexity they decided to give themselves more margin. Therefore they launched the CSeries in July 2008 and said clearly at the time that first flight was scheduled for the end of 20012. They also said that first delivery of the CS100 would take place at the end of 2013.
The only thing that has changed since 2008 is that at the beginning of this year they have started to say that first flight might take place at the end of 2012 or beginning of 2013. I think that is because they ran into some problems with the fuselage manufacturer, and possibly other issues, which have since been resolved as far as I know. Until today they have maintained a very tight grip on their suppliers around the world. It is an art that they have perfected ever since the time they launched the Global Express.
It is difficult to compare the CSeries with the A350 which is much bigger. The level of complexity grows very fast withe size, even though the technology remains comparable. BBD is now in the process of assembling the first prototype and I expect the roll-out to occur at the end of the summer or early fall. Airbus is assembling the Static Aircraft first whereas BBD is assembling the first prototype right away with the Static next in line.
When BBD developed the CRJ1000 they ran into serious difficulties with the software on the fly-by-wire rudder control. That might have been a good thing after all for it showed them how this kind of thing can impact on a programme, big or small. So they took defensive measures to prevent this sort of thing from happening again. That is why they created CIASTA, for Complete Integrated Aircraft Systems Test Area. That is where the Iron Bird is located. But it is much more than a conventional Iron Bird. All the systems of the aircraft will be integrated and tested simultaneously or in parallel. Boing and Airbus have similar facilities, but their respective set-ups are not as complete and sophisticated as CIASTA is.
Bombardier likes to keep a low profile until they have delivered on their promises. And they have a tendency to be more secretive. That is relatively easy for them because they are generally neglected by the less informed observers.
The CIASTA is a new technology from Bombardier AND CAE. From last november, Bombardier test many components 24hrs/day and 7days/week. From last march, the CIASTA system valid the integration of many components, 24hrs/day and 7days/week. It’s a big advantage vs the classical iron bird. So, Howard, they are coming fast and more faster than Airbus with the 350…It’s not unreal, but the fact:
http://www.bombardier.com/en/corporate/media-centre/press-releases/details?docID=0901260d80167ce2
And this for CAE:
http://www.cae.com/news/details.ashx?lng=English&location=AviationHP&showEvents=False&count=3&id=899&year=0
Perhaps the the answer to the question asked in the following link will be positive. http://wp.me/piMZI-2hn
Why did you leave Airbus back then, Prabowo?
KDX125,
Why are you so personal? I can send you my CV if you need it. By the way, my identity (in relation with my blog’s name Vero Venia) has never been a secret. Perhaps you feel brilliant having found my real-life name, but you should be ashamed by your bad intention. Perhaps you think I was fired from Airbus? No. I left voluntarily from the company to start a new life.
At one point, Airbus proposed a voluntary leave incentive to everybody who was considered as “overhead”in the Power8 cost cutting program. My whole department and others were tagged as “overhead”, it was a very good opportunity to leave, you just can’t refuse the incentive. So, I took the incentive and started my own business ( http://wp.me/piMZI-3A ). When it failed in 2010 I accepted an offer to go to Canada. Hey, I was still worth something in the job market!
Airbus is a very good employer and I lived a very interesting professional life, but after more than 21 working in Toulouse and 11 years as Airbus employee in different areas including Marketing, Structural Engineering, Aircraft Performance and Future Projects, I felt the need for change.
( http://wp.me/piMZI-1Ls )
Do you think it is a wrong to change? This is a globalized world where you need to be dynamic and flexible.
http://wp.me/piMZI-ZB
To be frank, at one point in your life you need to change. The comfort is such that you just don’t want to leave. At one point I asked if people should not ask, “Am I still attractive in the job market?”. I can understand that people can stay in the same company from start to the retirement.
In Toulouse, I also worked with people who are either bored int heir work. I worked with many people with very low motivation. I met people who had nervous breakdown. I told them, “Change job, find another company.” The answer was always, “Where can I have a job with 8 weeks of paid holidays and 14.5 months of salary per year?” I can guarantee that France is the best place for work, but some people need more than just money and holidays. There is more that you should expect from a work, namely satisfaction and challenge.
It is a pity that you spend even ten minutes just trying to “unveil” my name when you can simply send me an email.
Don’t worry, I”ll always as objective as I can toward Airbus, Boeing and others. I also am bound by the deontology / ethics and thus only public information is available on my blog. There won’t be any proprietary information that will be published in my blog.
OK, Everyone: knock off the personality stuff and return to the issues or I close the comments.
Hamilton
VV I find it odd to continue saying the NEO is bad timing. It sold 1400 and has the competitor at the IC. Further orders are slowing only because the A320 backlog has gone to 3300 having a profound impact on prices and delivery slots.
Hopefully Boeing will have a comeback this year. Sofar order intake, customers, prices and conditions have been unimpressive and parity is a far away business goal.
keesje,
You said, “VV I find it odd to continue saying the NEO is bad timing. It sold 1400 and has the competitor at the IC. Further orders are slowing only because the A320 backlog has gone to 3300 having a profound impact on prices and delivery slots.”
Your last sentence is the answer of your question in the first sentence.
It is very odd you can put two subsequent sentences without making the relation between the two.
There was not any reason to launch the neo when the A320 Classic backlog was still at 2,200 units. The only effect of the neo premature launch is the fall of the A320 Classic value. Don’t forget that the A320neo premature launch put the upper bound of the Classic version to 2016 or 2017.
In reality, LEAP was under development for the C919 and the PW1400G is under development for CS-21. Airbus could have waited until 2013 before asking a firm engine configuration to CFM or PW (based on LEAP and PW1400G) for an availability in 2016. The A320neo launch could have waited until 2013 too.
“”It sold 1400 and has the competitor at the IC. Further orders are slowing only because the A320 backlog has gone to 3300 having a profound impact on prices and delivery slots.”
– Your last sentence is the answer of your question in the first sentence.”
Well you can still get 2016 slots. At prices (almost) no operator wants to pay. High demand / little competition / limited availability -> forget discounts. A bit worrying for Airbus might be that slot availability for UA, DL, BA, LH, AF etc. is limited. There are worse problems then too many customers though..
If Airbus could had waited until 2013 before asking a firm engine configuration to CFM or PW (based on LEAP and PW1400G) the CS300 probably would have more orders (slots) at PW and Airbus wouldn’t have stolen away AA (130+395), Republic, Norwegian and Qantas..
And what about United/Continental? 2 Months ago everybody was celebrating the MAX win. Then it became silent. Maybe United took a look again at the A321 NEO PW1400G versus the 737-9 MAX and further evaluations are ongoing? I hope they have long, cool runways in the Caribbean..
forgot to mention that I discussed about the PW1100G and PW1400G here: http://wp.me/piMZI-2pz
keesje,
I really hope for Airbus that airlines would be willing to order an aircraft which burns 15% more fuel for a delivery in 2016 when there are more and more options NOT TO buy them, like using leased older aircraft as a stop gap (interim lift) during four or five years.
It is much cheaper to burn more fuel fuel during four years than burning 15% more fuel fuel during the whole life of the aircraft (new built A320 Classic delivered in 2016)
I discussed about this in my blog entry here: http://wp.me/piMZI-2dG
You can get NEO’s in 2016 if you want. Talk to Airbus or the leasing firms that ordered them. They probably won’t be cheap. Used A320s or CEO’s could be a better idea depending on conditions, operations, prices..
keesje,
You said, “You can get NEO’s in 2016 if you want. Talk to Airbus or the leasing firms that ordered them. They probably won’t be cheap. Used A320s or CEO’s could be a better idea depending on conditions, operations, prices..”
It seems that you start to understand a little bit better now. Your sentence simply means that ALL A320 Classic that will be delivered in 2014 onward will lose its value significantly.
It does not mean that the lease rate of the A320neo will increase compared to the current (2012) A320 lease rate.
You can play different scenarii if you wish, you will always come to the same conclusion. I did it myself and that is why I expressed my opinion repeatedly. Since you do not agree with my opinion, the only solution is to wait until 2015 and see what will happen then.
The same rationale applies to the 737 MAX, although Boeing clearly mentions that the firm configuration will only be achieved end of 2013. So, I can’t speculate much about it whereas the A320neo – “small risk modification” configuration is already well known.
So, as long as Airbus does not change A320neo configuration, I stand firmly beside my opinion. In my humble opinion there are chances that some changes will come later this year or next year.
in 2016, the first alternative reengined aircraft is at least two yrs away..
So, they can simply wait or perhaps buy alternative aircraft like the CS300.
Maybe some smaller airlines will be happy to order CS300 and take delivery of the efficient aircraft as early as 2017. It seems that you are just supporting Mr Pierre Beaudoin’s idea that Bombardier must NOT make any pricing concession now.
I’m not understanding why I am supporting a Mr Beaudoin.. but I guess the CS300 is significantly smaller then an A320.. & capacity does matter. On price concessions, there are OEMs that deeply discount and boost record sales in the media, write off costs on the first 1400 aircraft to proudly present positive quaterly results shortly after. And are getting away with it, because everybody wants to be excited, specially stock holders that are there for the next opportunity to sell & make a profit. I guess I’m conservative & old fashioned in tnat respect..
There are: one of them is DL. They stated their preference for the 737-900ER over the 9MAX as in their business model lower capital outlay is more important than lower fuel costs. And they are definitely not an exception.
If your business model is to offload your planes after 5-7 years when the value is still good, then the MAX or NEO are the only options. If your model is to fly till the cycle limit is reached and the scrappers call, why not a late 320 OEO or 737NG at a very good price?
Boing seems to have a buffer of 6 month in the planning, for the A737-Max !
Certainly Airbus has the same amount for the A320 NEO (P&W powered) … since they may fly, beginning 2014 !
I just imagine the Marketing men pushing both side, and the Engineering hitting the brakes with both feet !
An interesting interwiew of MAX’s chief project engineer, Michael Teal, by Guy Norris and Michael Mecham, on AviationWeek today !
A lot of new details emerge, through a very conservative approach !
Good to see serious comments from Boeing’s technical people !
http://www.aviationweek.com/Article.aspx?id=/article-xml/AW_06_18_2012_p54-465857.xml
Otherwise, the latest news from the PW1100G are here :
http://www.hmgaerospace.com/news/show/3691
Obviously the engines will be the key , and P&W seems to be on the good way to deliver on time and may be better than spec’s !
Apart from what obviously seems to be far more expensive undertaking than what is required for its competitor, the major revelation in the AW&ST story is the bypass ratio of the Leap-1B engine on the MAX: 8.5:1 bypass ratio.
–
The bypass ratio of the Leap-1A engine on the A320neo is apparently 10:1
http://www.flightglobal.com/directory/detail.aspx?manufacturerType=Engine&navigationItemId=382&engineId=1949&searchMode=Manufacturer&units=Imperial
–
In a recent comment CM claimed that the Leap-1B engine will be tailor made for the MAX (i.e. similar pypass ratio as the Leap-1A engine).
Perhaps CM could explain why the bypass ratio differential between the Leap-1A and the Leap-1B is now close to 100 percent greater than the bypass differential between the CFM56-5/7 engines on the A32X and 737NG? It wasn’t supposed to be like that, was it?
–
Addendum:
Oops, my bad!
The bypass differential is nearly the same (eg: 5.1/5.9 and 8.5/10)
However, the question still stands. The CFM MAX engine has not closed the “gap” bypass-wise with the NEO engine. Why?
Just to note : The PW1100G, will benefit of a BPR close to 12 …!
The still unclear response from CFM, is : For the LeapX … how much MMX will be used, CFM are struggling to push temperatures up, to somewhat compensate the lost efficiency, but it’s still unclear if this technology will be used, up to the moving parts, the HPT rotor and blades !
Today nobody know, if NEO, or MAX will get the Ceramic Matrix Composite, apart in some static vanes, may be the MAX, may be both, and … may be none !
Not sure at all CFM, can meet required time on wing and maintenance cost, with a technology imported from military engines, the CMC in this case !
IMO, the LEAP-1B will be maxed out technology wise at EIS, while the PW1100G, with the expert help of RR, could easily be further improved in the SFC department, by another 5 percent a decade hence. The GTF is a rather conservatively designed engine. The Ceramic Matrix Composite (CMC) technologies slated to be used on the LEAP-1B is unproven in flight conditions as of yet. The Technology Readiness Level (TRL) for CMC engine core technologies is at TRL 5. The GTF is at TRL 7. After the the completion of flight tests for the C-Series, the GTF should reach TRL 8. The GTF will finally reach TRL 9 a couple of years after EIS of the C-series.
http://esto.nasa.gov/files/TRL_definitions.pdf
That is a clear indication that ground clearance has always been a problem, and still is. So, as I have said before, if CFMI wants to keep the 1B competitive with the 1A, some sort of compromise might have to be found in the 1B core. Although I am not absolutely sure of that.
Since the 737 MAX is sill undefined at this stage, we wont know for a while if the MAX will be as competitive with the neo as the NG is with the ceo. But if there is a performance gap between the 1A and 1B equivalent to the expected gap between the 1A and the PW1100G, it will be difficult for Boeing to retain parity in the NB market.
But I am sure CFMI will do everything it can to make the 1A and 1B as close as possible in terms of performance. Where I am less confident is whether or not they will succeed. Especially over the long term when both the 1A and 1B will be further developed and refined. It seems to me that the 1A has a head start since there is little compromise in its initial design, whereas the 1B might start with a small handicap.
With the NEO’s LEAP engine CFMI is fighting a direct battle with Pratt’s GTF. And the NEOs’GTF looks good. Therefor there is enormous pressure on CFMI to realize every possible percent point sfc improvement on the NEO’s LEAP engines possible.
The MAX LEAP-1B engine has no direct competitor on the MAX. CFMI will try to reduce additional investments as much as possible. Standardization of the core with the -1A seems obvious.
Interesting com from “WordPress” June, 4 it seems to be serious !
http://cfm56.wordpress.com/2012/06/04/5/
The LeapX in the 16% better than a CFM56, now, but which one ??
May be just a Mktg hype ?? hum !
The LeapX for the C919, will get through certification first, in 2014, largely ahead of the plane !
Interesting, CFM is holding on the initial timing !
But, the NEO will certainly fly largely ahead of the C919 !
Keesje :
I think the LeapX B will have a reduced (new?) core, slightly down scaled, adapted to the lower max thrust, needed by the B739 MAX , not a new motor but … there are quite a lot of differences !
So, CFM has a lot of work and trials ahead , and EIS, on time and at spec’s for the Max may be a little bumpy !
And may be the same for the NEO, I do not see the 15-(16 %Now ?)% promised by CFM, to be effective in 2016, at least for the first year !
a new (slightly) downscaled core with a new fan and relocated accessoiries = a new engine.
something CFMI will try to avoid at any costs. CFMI won’t be pressured to do so, for every -B not sold they can sell an -A, Boeing sidelined them when the NSA was the routemap ahead, Boeing is talking to RR about a 777-X engine and left GE in the cold when the 787s GENX engines were delayed 4-7 yrs.
Downscaling a core for a 10% lower thrust, when the trend is up seems non- sense from a CFMI /GE / Safran standpoint..
It’s quite certain they will use less LPT stages, to move the smaller fan … and a “Smaller core” speaks for himself ..;
Certainly the same technology, but wait for huge différences …
To try to meet Boeing exigences !
So it’s going to be somewhat a new engine !
CFMI will sell roughly twice as many engines (more if GTF is significantly better) for Max than Neo so it is in their best interest to make the Max more competitive and their business case is better.
One detail that keeps getting overlooked is the -1B should be much lighter (smaller core, smaller fan, fewer CFRP blades) which reduces the weight – better for short flights.
Also, as to thrust always increasing – the 777x engines have lower thrust than -3ER. This core be better sized for a NSA.
http://cfm56.wordpress.com/2012/06/04/5/
Is that originating from CFM or is it a hobbyist effort ?
I would be extremely surprised if there was standardization of the core, even though it would considerably more economical for CFMI to do so. One obvious reason is that a smaller core diameter on the 1B will give additional ground clearance to the MAX, which has little to spare. Another one is BPR. If CFMI were to use the same core on both the 1A and 1B, the reduced fan diameter on the 1B would yield a smaller BPR. Standardization is therefore out of the question.
CM made an excellent analysis of this in a recent thread (“737 MAX vs A320 neo: The debate continues”)
(Sorry about the quoting problem above: the quote attributed to keesje is actually Normand, and the rest is mine. But no way to edit the comments after posting …)
No doubt wants a dedicated, tailored core, at no extra costs, same time on wing, MRO costs. They still have to generated 27 klbs, maybe more, for the 737-9 in the same efficient way. The 737-6(00) is unlikely to be build agian, the 737-7 will likely be marginalized by stretched RJ’s.
A fishy business case for CFMI. Develop a second LEAP engine, alongside the GE90X, E-190 engine, GENX ramp-up and Passport development.
A entirely new core, highly unlikely.
Ok Keesje !
Not a truly new engine … the same technology ..
But partly scaled down,
Not the same stage account for the LPT ..
An may be more CMC parts incorporated, to cope with efficiency !
Nearly all the hurdles, trials and certification of a new engine, but quicker and at a lower cost !
And may be the same results, like the transition of the GEnx from the B787 to the B748 !
Sure, GE & SNECMA will make it, but maybe we see some PIP’s coming up through 2018-19 just to meet the spec’s !
GEnx-1B to -2B was near identical core, only change was some part of the HPC due to customer bleed being added to the -2B (the -1B is for all eletric archi. remember?). Everything else is same.
-2B even kept some of the major frames (IMC, MTF) for the -2B to protect schedule and cost, so it is somewhat heavy compared to what could have been done.
2B has 1less LPC and 1less LPT stage, a 6″/5% smaller fan,weighs in at 600kg/10% less and has the pressure ratio of the highest thrust 1B version.
Another interesting growth examples is the cfm56 -7b -5b -5c
triplet.
The LPC and LPT are not part of the core. Core is HPC, combustor and HPT.
I wonder how long until Boeing announces the NSA after the MAX is done? The sales numbers speak for themselves. And the NSA wouldnt need to be out of alien technology to beat A320, Al-Li would do for skin, composite wings is nothing new for Boeing at this point, more room for growth designed in from the start etc
I think the NSA is on the backburner until B realises the below 1000 sales wont improve, then they will rush to commit to the NSA to try to salvage the NB market.
“composite wings is nothing new for Boeing at this point”
I think you mean that composite wings is nothing new for Mitsubishi, Fuji and Kawasaki at this point.
“I think the NSA is on the backburner until B realises the below 1000 sales wont improve, then they will rush to commit to the NSA to try to salvage the NB market.”
What would that mean for the American and Southwest MAX orders? Both have made it pretty clear that they wouldn’t, or couldn’t wait for an NSA. Or do you propose they still do the MAX?
I’m just waiting for the first announcement of Al-Li parts in the NEO Vs MAX war !
Airbus has compromised hundred thousands tons of AL-Li … with Alcan !
Much more they may need for wide body aircrafts !
And Boeing will have to respond !
And since , as we saw, a lot of structural parts may be re-designed, the way is largely open !
The Al-Li War, in my opinion, may begin very soon, they will not wait for the NSA to incorporatae a lot of Al-Li parts in the NB !
Not only with Alcan:
http://www.google.com/search?q=airbus+aluminium+contract
http://www.google.com/search?q=airbus+aluminum+contract
Not 100% certain, but in worldpress they are not in this mood, mainly reports and transcription …
Seems to be in the CFM style, but I did not find the original. However I buy it …
Sorry !
Hello boys
16% fuel gain for the leap coming from here
http://www.cfm56.com/cfm-value/technology/x-power
Don’t know the date, but refers to mascot engine test -> mid 2010
So ?
Realism:
http://www.snecma.com/presentation,2414.html?lang=en
MASCOT : Moteur à Aubes de Soufflante en COmposite Taille LEAP
looks like a SNECMA programme.
I bet you if you do a survey on this blog and ask other members what they mean when they speak of the core of a turbofan engine, the answer for the majority will be: compressor, combustor and turbine.
The impression I have, and I could be wrong, is that your definition might apply to a turbojet engine only. If that is really the case, my explanation would then be that the evolution of the turbofan engine gave a new meaning to the word core. Here the fan divides the flow into two distinct sections: the bypass section and the core. In other words the bypass section produces the outside flow (bypass flow), whereas the core produces the internal flow (core flow).
Normand,
the definition I gave is the one used by engine OEMs (I have worked with three of the major four – GE, PW and RR, not Snecma), i.e. the core is the high pressure system (HPC, CC and HPT). The low pressure system (fan/LPC and LPT) is not part of the core. The core is also called the gas generator, i.e. it generates the gas to drive the LPT (and hence fan).
Whether the frames between LPC/HPC and HPT/LPT are part of the core or not is up for debate…
I do agree it might be confusing for newcomers to aero engines.
If the turboshaft is single shaft architecture, the core is also the whole engine, of course.
Thanks for the explanation. I had noticed before that OEMs use HPC, CC and HPT as a definition of the main core parts. But on the other hand I have the impression that many of us, who are not propulsion engineers, have a different usage of the word core. And there is a reason for that.
As I have mentioned in my original post, the way I see it is that OEMs have retained the original turbojet designation for core, but for a turbofan engine many of us need a name to differentiate the fan section from the other smaller diameter power sections of the engine. Therefore we will use the word core quite often to designate the LPC, HPC, CC, HPT and LPT. Although it is technically wrong to do so.
I would appreciate your thoughts on this.
I would not use the term core for the “smaller diameter” part of the engine, I think it confuses even more (especially when you read other literature where they use the term and mean HPC, CC and HPT).
But we might need to come up with something to designate this smaller diameter portion… contest anyone?
Forgot: google aero engine core, pick the first link, it will give you an idea.
Interesting.
NEWAC : MTU
do all the leading edge project have european backing?
That is exactly what I had done before writing my original post. The various links that came up all said the same thing: The core is composed of the compressor, combustion chamber and turbine. In their definition of the word core, none of the links I went through separated the compressor and turbine into their respective LP and HP sections.
I knew that OEMs use your definition, the official one. But I am not comfortable with that definition for the reason I gave you before. For this particular issue, Internet did not help me very much, including Wikipedia. I would have had to hit a link reserved for specialists to find the proper usage of the word core.
Uwe, NEWAC is not only MTU, but also RR, Turbomeca, Avio, Volvo Aero and Techspace Aero and all the usual bunch of unis and institutes on top of that. MTU coordinated the whole effort, that’s why their name is in bold type.
Many research projects have EU backing in the shape of the Frame Program (now on version 7 btw), especially the ones for the far future or for key technologies (heat transfer for example), but also some demos with more mature technology (google the Antle demonstrator).
A lot is still done in-house, especially the most sensitive stuff (might be nationally funded). Most of it a much like the NASA programs GE and PW are involved in (GEs E3 program comes to mind).
Normand: the NEWAC project was for core technologies only (NEW Advanced Cores), nothing for the low pressure system (as it happened that was done in the VITAL program). The reason I recommended it is because it has some good pics (click on About then one of the SP’s).
I also doubt Wikipedia would be much help in this case… you need websites intended for professionals (and there are not that many, too low volume of users I guess). If you want to read more, actual books are pretty good (Cohen, Roger and Saravanamuttoo is not too difficult, also the ones by Gunston are good, I like the one on the early jet engines).
Why not calling it “the motor”. 😉
The only Gunston book I have is “World Encyclopedia of Aero Engines” (5th Edition). It was of no use for our problem though. I went through other books in my personal library and they are no different than what I found on the Internet.
“Jet Engines” by Klaus Hünecke, shows the LPC and LPT sections under “core engine”. In “Aircraft Powerplants” by Bent McKinley, there is an illustration of a CF6-50 that has the HPC, CC and HPT under “Core”; but then they show both the Fan and LPC under “Fan”. In Pratt & Whitney’s “The Aircraft Gas Turbine Engine and Its Operation” they have a drawing of a Gaz Generator which includes the LPC, HPC, CC, HPT and LPT.
Yet I know you are right mneja. But don’t be surprised if you still see me using the term core which would include the LP section. But the more I think about this problem, the more sense it makes to simply call this part of the turbofan engine the “Motor Section”. Or if we want to use the word core in the loose sense, we could put “motor section” in brackets, like this: core (motor section). While we are at it, why not just call it the “MS”. 🙂
🙂
But you are right, it is very confusing.
It is just that we need to consider this when CFM say this and this engine share a common core (CFM56-5 and -7) they mean the high pressure system only, with a different fan everything on the LP shaft is different.
You make me look at this differently than I used to. So when I will hear that two engines share a common core, it will now mean that everything on the HP shaft is the same, whereas everything on the LP shaft might be different. I never looked at it this way. I like it!
For a three-spool engine, I imagine that for two Rolls-Royce engines that would share a common core, it would go like this: Everything on the HP shaft is the same, whereas everything on the respective IP and LP shaft might be different.
I assume that the fundamental reason for wanting to share a common core is the fact that the gaz generator is very expensive and would be complicated to modify for a specific derivative; but on the other hand it can easily be derated with the appropriate plug.
You are spot on: the gas generator is extremely expensive…! Much of the money is in the HPT, with cooling, coatings and what have you, but the HPC is no bargain either.
The LPT is easier overall due to lower temps, but influences the fuel burn more (due to its direct connection to the fan, from which the majority of propulsive power comes), so the aerodynamics need to be more optimized. Plus: it has more stages. If you change the fan you better modify your LPT, or you’ll mess up your engine…
The HPT with its special cooling and super high tech casting (singel crystal these days) is something you want to keep the same if you can.
For the HPC it is a little the other way around: the HPC has many more stages than the LPC (typical stage ratio > 2) and influences the overall performance more than the LPC.
It is relatively easy to add a stage or so to the LPC, you must change the LPT anyway if you modify the fan. You can possibly do minor stuff to the HPC (change blading, removing maybe the last stage and so on), but you generally want to keep it as similar as you can, or you need to change the HPT as well (the power delivered from the HPT drives the HP shaft with the HPC so the latter better consume what the former delivers, not more and not less).
You do not plug the core, it is not that simple. What you do is what I said before, play with the stage counts in the LPC and LPT to match the overall pressure ratio (OPR) you need and to match the LPT power to that of the fan + LPC.
RR is difficult, most likely it is like you say, but I suspect they sometimes keep the IP shaft stuff the same too (if they can), if two engines are very similar. I think for example that Trent 700 and 800 share the IP turbine, but have different IP compressors. I have seen a chart of this once, but I do not have it anymore.
What I meant is that if you start with a standard engine and add a derivative that shares the same core, you can plug the derivative to derate it. Or put differently, the FADEC will manage the two identical cores differently.