737 MAX vs A320 neo: The debate continues

Here’s the next round in the continuing debate.

Bernstein Research published this chart detailing how Airbus and Boeing differ on the performance improvements they predict.

There is, of course, no way to know who is correct until the airplanes enter service.

We hear the A320 sharklets are performing better than advertised (Aviation Week actually reported this a while back as well). If the figure we’re hearing proves correct, the neo and MAX should have parity.

62 Comments on “737 MAX vs A320 neo: The debate continues

  1. There is no parity in sales, not for the current ng vs A320ceo nor parity in orders between MAXvsNEO. Boeing has dropped the ball imo. Get that NSA done and stop this fiddle with a 1960´s frame that had its day 10 years ago. Invest some of that 10B cash into something more useful than dividends!

  2. This is still a war of words between two paper airplanes.

    If you want to add more confusion, assume that A and B use different margins for peformance guarantees. On top these margins are different between the engine OEMs 😉

    While we are at it: Shouldn’t we differentiate between NEO/PW and NEO/CFM? I’d expect a few percentiles in favor of the GTF.

  3. Interesting. At one point A was stating that the best that B could do on the engine was 8%. Is the 12% an A number or a Bernstein number?
    Until final configuration I would think that all these numbers are fluid and that the “war of words” is mostly hot air.

    I am thinking that B is undercutting price to maintain market share which is placing pressure on A to match. I would opine that B is still making decent margins but is willing to sacrifice some to make sure the market share does not balloon too far towards A. As long as the WB market is a B stronghold (777, 787 sorting out), this seems a good strategy until they can address the NSA. A is highly dependent on the 320 line and the 330 line but faces a dropoff in 330 orders in the next couple years. The 380 is not exactly smooth sailing unfortunately, though they will eventually sort it out. Thoughts?

    • afair A said “B will have difficulty going beyond 8% effective improvements”.
      ( i.e. engine gain _minus_ drag increase and other losses )
      Later B added an improved tail and the split tongue winglets.

  4. I don’t see why Airbus is under pressure to discount. It seems they have the best product, biggest backlog and big prospect likely to move when more slots become available (AF, LH, BA, UA, Chinese, 757 operators). Boeing & the MAX proves a different ballgame though..

    I think Bernstein is very positive on the MAX gains. I think the improvement gab between MAX and NEO is 5-10% (5% much bigger fan, 2% wingtips, 2% GTF, 1% OEW). And we will never know officially because Boeing will deny/ confuse everyone forever about it.

    I think / hope Boeing won’t wait long with a real answer. Political help (Lion, China) and discounts seem unsustainable sales tools. Blunt Denial proved damaging too (“we can wait, the NG Plus will do, customers will wait, no switches so far, parity has been restored, 50-50 .”)

    • I wonder if Airbus’s “biggest backlog” on the NEO needs to be understood in context. They had a year jump on Boeing which may very easily draw even by the end of this year. If Boeing is committed to a 50-50 split in the single aisle (and everything says they are), then perhaps their strategy is working since most analysts say they make their “real money” on wide-bodies. The 777 sold 200 copies last year alone! The A380 sold 250 airframes in 12 years and is costing them money right now. Boeing rarely predicts sales but their recent giddiness about 2012 sales makes one things they have a good hand going into Farnborough. If Boeing is being aggressive in selling the MAX, then good for them.

      • Drawing even with the NEO would require probably 1500+ firm orders for the MAX in the next six months, assuming that the NEO wins only 500 more before the end of the year (currently the firm orders stand at 451 MAX, 1425 NEO). I think even Boeing is not showing that level of giddiness.

      • What do we know about the pricing incentives that sold 200 777 copies last year 😉

        Not long ago everybody was sure about the NB lines being the bread and butter element of the business.

  5. Despite what some people hope, I think this performance/cost debate will continue long after both MAX and NEO have been in service. Just look at the barbs traded over the current 737/A320 family products in some of the other MAX/NEO posts.

  6. Whatever happened to the 0.5% improvement per inch fan diameter?
    Is that now to be regarded as a myth?

    • “the 0.5% improvement per inch fan diameter” is at the core of efficiency differences and behind the 5% delta because much bigger (10 inch) fan I expect. Its the best ignored, downplayed and overlooked reality in this debate.

      The A320s bigger CFM56s have a better sfc the the 737NGs CFM56s too. Its not far more complicated. http://www.jet-engine.net/civtfspec.html

  7. Dan Fabricatore :
    I wonder if Airbus’s “biggest backlog” on the NEO needs to be understood in context. They had a year jump on Boeing which may very easily draw even by the end of this year. If Boeing is committed to a 50-50 split in the single aisle (and everything says they are), then perhaps their strategy is working since most analysts say they make their “real money” on wide-bodies. The 777 sold 200 copies last year alone! The A380 sold 250 airframes in 12 years and is costing them money right now. Boeing rarely predicts sales but their recent giddiness about 2012 sales makes one think they have a good hand going into Farnborough. If Boeing is being aggressive in selling the MAX, then good for them.

    • everybody is euforic about the 777, and it is very succesful. Its the type left (vs 737, 747, 767, 787) to be proud of.

      there related realities too.

      – the 777-200ERs/LRs stopped selling some time ago and the backlog is gone, leaving Boeing without a 300 seater (787-9 delayed many years). Meanwhile the A333 got a reveival.

      – all 777s sold in recent years (300ERs) will be delivered before the A350-1000 becomes available. So while the 300ER is a great aircraft, no alternative being available helped too.

      I have the feeling some top notch airlines will order A350-1000s soon. We will see how many 777s will be sold for delivery after 2017. That will be the moment Boeing will have to modify the 777. The 777-9 will have a niche of its own, how the (still heavy) -8 will do remains a question IMO.

  8. I just think “Parity of perf’s” between Max and NEO, is only in the dreams of Randy and Scott !

    The actual war price is coming from Boeing, and for some reasons … is a strong indicator …;
    KDX 125 is right , just add 2% for the GTF case, and may be a little more after 2017 !
    But politically speaking, Airbus and JL, will not make the GTF dominance such an official fact !

  9. At what market share would Boeing rush the NSA? 60/40? If MAX will show the future market share numbers B will lose more market share. 1000 vs 1400 currently?

    Not that the NSA would help right now, but it might keep some customers loyal if they get a brand new Boeing NB in 10 years. I am not convenced MAX will regain the advance the NEO has. There needs to be more.

  10. I do not hink Airbus wants to produce more than 50-55% … they are not able to manufacture much more, in a short term !
    John Leahy just hope to get a better pricing, and not to have to invest more for the A320NEO, if he may avoid it !
    He needs 2 Billions for “His” A330NEO … to sold 5-600 more … dixit Keesje “Prévisions” !

    • There is also a growing worry at A+B about the order race holding orders that may never be delivered. If you biuld more capacity and have many orders cancelled that is no fun experience. The current NB backlog is a bit of a bubble IMO. After the finacail reaper doing a round some of these orders might melt away?

  11. keesje :
    “the 0.5% improvement per inch fan diameter” is at the core of efficiency differences and behind the 5% delta because much bigger (10 inch) fan I expect. Its the best ignored, downplayed and overlooked reality in this debate.
    The A320s bigger CFM56s have a better sfc the the 737NGs CFM56s too. Its not far more complicated. http://www.jet-engine.net/civtfspec.html

    Well, according to the link, the A320 CFM engine is .330 vs .0380 for the B737. Now, I don’t know how these two numbers will translate to. But looking at the fan diameter of the two engines (68″ A320CEO vs 61″ 737NG). Is the CFM 56-5A really 3.5% more efficient? and if so, this would imply that the A320 is over 3% more efficient than the B737. I have not seen many airlines publicly say that as far as I know for the A320, but Lufthansa has said so about the B737 being 2% more efficient than the A320. I believe that was the MAX vs the NEO comparison too. So what gives???

    • The CFM56-5 and CFM56-7 share a common core. The smaller fan on the CFM56-7, combined with a core which is oversized for the thrust needs of the 737NG results in a TSFC penalty and a sub-optimization of the 737NG today. The 737NG overcomes this with a lighter airframe, a higher L/D wing and lower thrust used on any given mission, compared to the A320.

      The fact the 737 MAX is now getting a bespoke core makes the whole issue of trying to make apples-to-apples comparisions of fan diameter moot. You now need to compare the bypass ratio and OPR to get a better understanding of how these two engines will compare on a TSFC basis.

      • engines used on A320/737-800 resp:
        Model Thrust SFC T-cruise SFC-cruise ( lb/lbh )
        CFM56-5B4 27,000 0.340 5,000 0.545
        CFM56-5B4/P 27,000 0.340
        CFM56-5B4/2 27,000 0.340
        CFM56-5B4/2P 27,000 0.340

        CFM56-7B22 22,000 5,450
        CFM56-7B24 24,000 0.370 5,480 0.627
        CFM56-7B26 26,400 0.380 5,480
        CFM56-7B27 27,300 0.380

        ~5% more thrust @ 15% better sfc in cruise
        explains the A320 long range advantage.
        data via http://www.jet-engine.net/civtfspec.html

        OEW differences are nonexistant. ( going by Manuf. data )
        Installed lower thrust is mostly due to cert changes
        overridden for the NG by grandfathering of the original.

        comparable seatsfc would indicate that the A320 is
        about the seating difference better in blockfuel ~8%

        -8% is in the range of (+5% – 15% )

      • The CFM56-5 and CFM56-7 share a common core. The smaller fan on the CFM56-7, combined with a core which is oversized for the thrust needs of the 737NG results in a TSFC penalty and a sub-optimization of the 737NG today. The 737NG overcomes this with a lighter airframe, a higher L/D wing and lower thrust used on any given mission, compared to the A320.

        The fact the 737 MAX is now getting a bespoke core makes the whole issue of trying to make apples-to-apples comparisions of fan diameter moot. You now need to compare the bypass ratio and OPR to get a better understanding of how these two engines will compare on a TSFC basis.

        Can you translate the acronyms for those of us who don’t know all the jargon, please?

      • OPR = overall pressure ratio
        TSFC = thrust specific fuel consumption (sfc normalized with thrust)
        L/D = lift / drag

        OPR is important as it gives higher efficiency of the base gas turbine. This is one of the base parameters in the Brayton cycle, aka the gas turbine cycle, another important one being T3 (temperature after combustion before entering turbine).

        Basically all engine developments have focused (and still do) on improving either the propulsion efficiency (through increasing BPR) or by improving the base gas generator (through higher OPR and/or T3). All other engine developments are just means to achieve this (except lower weight). This is the only way until something is done to change the basic cycle that the engine uses.

        The latter can be done through e.g. intercooling between IPC and HPC, regeneration of turbine exhaust heat, bla bla.

  12. Dan Fabricatore:
    I am sorry to disagree with you on every point you make.
    The most unrealistic once are: “They (Airbus had a year jump on Boeing which
    may very easily draw even by the end of this year.”
    The fact this, that Bowing was asleep at the helm and never saw the NEO
    coming until it was too late and there is no way that Boeing will draw even by
    the end of this year, if ever, with over 2000 and D.O. setting being sold, while
    Boeing is still struggling to confirm the specification and operating costs of the
    MAX, putting all so-called orders for the MAX up in the air!
    Stating “that their (Boeing’s) strategy is working (and everything says they are),
    since most analysts say they make their “real money” on wide-bodies,” is con-
    tradictory. Which Boeing strategy his working? Hurriedly reacting to the NEO,
    after A. already had firm commitments for over 1000 units, which by now has
    risen to more than 2000 firm commitments, while Boeing is still trying to find a
    way to make the MAX provide operating costs as close as possible to the NEO,
    which It never will?
    And, if I may ask, which of “their strategy is working since most analysts say
    they make their “real money” on wide-bodies?
    The 787, 747–8 or the 767? Only ONE Boeing widebody out of FOUR, the
    777, is producing extremely good profits for Boeiing so far!

    • Wouldnt a simple reengine do until the NSA could enter the market? Call it MAX-lite. Why pour a lot of funds into an airframe that is overdue to be replaced? It will probably never see even 1000 firm orders sadly. A very costly decision instead of going NSA as they were doing. Say it would be 8% better than the NG, its plenty if a brand new NB waits for you in 10 years time?

      Boeings future is in danger IMO, the 777 cant finace the whole comapny and now their military contracs will shrink too. The first thing they have to do is to kick all the McDonnel beancounters out. Let engineers run this company.

      • “..its plenty if a brand new NB waits for you in 10 years time?”

        Wrong timehorizont. You could maybe order in 9 years and
        get delivery in another 7 years all things going well.
        The window for an NB done in new tech _and_ providing significantly better efficiency has not opened yet.

        Boeing tried to drag customers into the “right around another corner” path but rightly lacked coercive strength.

        The MAX is Plan B for B.

    • So let’s draw a couple scenarios:
      1. B gets an additional 600-800 firm commitments for the MAX at Farnsborough totaling out at ~1200 commitments (Currently ~450 firm). A currently has 1400 firm commitments. The percentages are approximately 54%:46%. A is sold out, but willing to overbook to ensure against defaults on orders so sells a few more, but only has so much wiggle room. B is willing to cut margin because it feels it can still be profitable enough and does not want to concede market share. B has delivery slots and eventually closes gap to say 48%:52%. Status quo.

      2. B fails to attract buyers at Farnsborough and loses momentum and only gets 200-300 commitments. This would be a telltale sign that there is something wrong with their product as airlines are not interested in buying an inferior product. B would have to either a. Cut margin more b. Introduce new product. Advantage A.

      So Farnsborough will indicate which scenario is more likely. A-netters aside, airlines don’t have the luxery of picking an airplane because they are fanboys for one company or another. And with margins so tight, $ talks and Bull— walks…

      An interesting thought that was brought up is that the aircraft manufacturing business is a cash flow industry. Since both A and B have already sunk costs into their current WB offerings the fact that they are manufacturing and more importantly delivering planes would be a positive factor. So I think Dan has a point in that although the 787 program is as a whole in a negative posture, it is now delivering planes and bringing in positive cash flow. Same for the 747-8 program. 767 is paid for so all if gravy there. 777 is really gravy and commands a premium.
      For A on the WBs, the 380 is delivering, but unfortunately the wing issue is essentially creating negative cash flow (and resource flow) for this year at least. Perhaps they are getting some positive cash flow, but certainly not what they expected (maybe 1/2?). The 330 is great, the 340 is dead, the 350 is negative with delivery a ways away.

      • Interesting analysis. But even if Boeing was to garner many “firm orders” at Farnborough, those orders would still be tied to future performance guarantees. But there are no guarantees, so to speak, that those performances will be met with the compromised LEAP-1B design.

        And if in the end the specifications are not met the airplane/engine purchase price would go down proportionately. It’s in the contracts. Both the engine and airplane manufacturers would be impacted. For the customers it’s hard to tell how much they would be impacted because it’s tied to future oil prices.

        In regards to the A380 woes, we have to remember that the 747 nearly pushed Boeing into bankruptcy in the early seventies, before becoming a very successful programme afterwards.

  13. Uwe :engines used on A320/737-800 resp:Model Thrust SFC T-cruise SFC-cruise ( lb/lbh )CFM56-5B4 27,000 0.340 5,000 0.545CFM56-5B4/P 27,000 0.340CFM56-5B4/2 27,000 0.340CFM56-5B4/2P 27,000 0.340
    CFM56-7B22 22,000 5,450CFM56-7B24 24,000 0.370 5,480 0.627CFM56-7B26 26,400 0.380 5,480CFM56-7B27 27,300 0.380
    ~5% more thrust @ 15% better sfc in cruiseexplains the A320 long range advantage.data via http://www.jet-engine.net/civtfspec.html
    OEW differences are nonexistant. ( going by Manuf. data )Installed lower thrust is mostly due to cert changesoverridden for the NG by grandfathering of the original.
    comparable seatsfc would indicate that the A320 isabout the seating difference better in blockfuel ~8%
    -8% is in the range of (+5% – 15% )

    The cruise SFC number for the -5B is definitely not correct – way too low!

    • I think the 5B of similar thrust range have a significant lower sfc then the -7s.

      http://www.togo84.com/spec05_gas_turbines.pdf

      Not surprising because they are basicly the same engines but the fan /BPR of the 5 are better. And they e.g have a more efficient inletshape and less body interference.

  14. The MAX is Plan B for B.

    Well looking at the orders A vs B the plan B has failed badly and I can imagine a few inside B being of a different opinion than you and the former McDonnel bean counters. New tech, well compared to the 737 that is a 1960´s design anything i new tech 🙂

    Ok I know you hate B, but what would you do if you were in charge?

    • I don’t know for Uwe, but I love Boeing and would like to see it continue to prosper. And to ensure that I would drop the MAX immediately and would keep a small team working on the 777X. I would do the NSA as soon as possible and offer it with both the LEAP and GTF engines. And shortly before the NSA would enter flight testing I would start to gradually reassign the engineering workforce to work on the 777X.

  15. Here is my idea for B. I would go with keesjes idea, do a 100-150 seat frame in cooperation with Embraer, when that is done you can leave all NSA models below 150 seats alone, growing the NSA so the smallest member would seat 162, a straight shrink of the base model about the size between 738 and 739. With an upper end model in the size of the MS-21-400 but with more range to grow the NB upwards.

    Would Embraer take the bait? As they just cancelled any ideas on above 100 seat? Or maybe Bombardier would need some investment in their meager position right now? Better to be ahead of the market IMO than reacting late, the MAX was a rushed response. Go carve out a new niche of the future NB market now. Maybe this market i still small, but when large nuumbers of 767s start to be pulled away there will be more room. ANA said themselves the 788 was worse for short haul than even the 757. A larger NB with a high density cabin can be a very popular aircraft with growing fuel prices and growing asian domestic markets. 240/250 seats in a NB? A short haul shuttle for the Chinese domestic market? 220 seat TATL or EU-Africa etc..

    • All the manufacturers that have tried in the past to design an airplane in cooperation with Boeing have been humiliated in the process. Nothing ever came out of those projects except hot air. Think about the British with the 757 wing, the Italians with the QSHA and the Japanese with the 7J7. I don’t see why or how Boeing would let Embraer show their capabilities on an equal footing with them. And for sure if Boeing had cooperated with Bombardier on the CSeries, that aircraft would be terribly late and hugely over budget.

  16. en590swe,
    The problem for Boeing is that there is no “simple” re-engining.
    What will be the saving grace is that Comac, and the others are not ready!
    Its a sad day when I predict that Boeing will pick up crumbs from the Airbus table, but the thing that will save them is that Airbus will not be able to meet demand, with Boeing the only other game in town.
    This new strategy of Airbus offering a “fatt-ass” seat could have huge(no pun intended) marketing advantage as reality about the USA, Australian and Europeans having too many obese people becomes an acknowledged fact not an “inconvenient truth”.

    • Yeah its better to play it safe I guess, but I have a feeling the MAX wont cut it for very long, not having GTF engine option was a stupid idea. Seeing how GE screwed up on the genX, I wont hold my breath for the LEAP-X to be any better.

  17. Uwe :
    The window for an NB done in new tech _and_ providing significantly better efficiency has not opened yet.

    That is what everybody says. But I think it is being very optimistic to assume that the technology to achieve “significantly better efficiency” is to be expected in a not so distant future; 10 to 15 years being the most often quoted. We have arrived at a stage in engine evolution where quantum leaps are harder to come by. And by the way, to call the next generation of CFM engines “LEAP” is not only arrogant but also totally unrealistic. Even the P&W GTF is not that big of a leap, but an important evolution nevertheless.

    The noise barrier of the targeted engine technology for the next generation of NB aircraft will be a lot harder to brake than the aircraft sound barrier was in 1949. Not counting the other numerous roadblocks that open rotor engines have been facing for the last twenty years. If that is where the future lies, then the future is bleak.

    In 2004 Bombardier had a new NB aircraft design but they did not have an engine for it. In 2007 they found one. The CSeries is an evolutionary aircraft and its PW1400G is also an evolutionary engine. But both are still very efficient by today’s standards.

    Airbus responded to this challenge with the neo. But there is still a sizeable gap in efficiency with the more modern CSeries airframe. If the latter had the same seating capacity it would simply destroy the neo business case.

    Boeing also had an opportunity to respond to both the CSeries and neo with the NSA. But its leaders were so caught-up with the 787 fiasco, and numerous other problems, that they finally dropped the ball. This will turn out to be a very costly mistake. They will spend a few billions to remain behind Airbus instead of taking the lead for a few billions more.

    • My words exactly, stop fiddeling with the MAX that wont sell that great anyway, do the minimal engine update and go on with the NSA. The NSA can grow into a role that the 737 cannot. Its not just about technology IMO, its growing the market upwards, even a high density c-series will be nipping at the 737s heels.

      Leave the below 162 seats to the rest and go for ex 757 and 767 space in the lower region.

    • The NSA project is the only strategic move for Boeing in the NB, the only supposed to do with their history of vision. And at the end of 2012, with the first fly of Cseries, ti will be the real starting gun to understand the danger of costly mistake with statistics of GTF, etc. So, at this time, wait and see…

  18. “the 0.5% improvement per inch fan diameter” is at the core of efficiency differences and behind the 5% delta because much bigger (10 inch) fan I expect. Its the best ignored, downplayed and overlooked reality in this debate.

    It’s not that simple; its not just fan dia.

    The IAE V2527-A5 has a 63.5″ fan dia and is generally accepted to have appx 1.5% better fuel burn than the CFM56-5B with a 68.3” fan dia, at equivalent TO thrust ratings, on the same A320-2 airframe.

    We are still talking rubber airplanes.
    Wait until the first flights.
    Till then it is all speculation.

    • we are comparing two CFM LEAP engines, one with a bigger fan. I think we can predict the sfc pretty well, just like the guys who spend billions ordering them. Nobody has to wait for first flight, modelling supported by windtunnel and engine testing proved surprisingly accurate during the last decade.

      • Keesje,

        I know you want the fan diameter argument to stick, but it only works for people who don’t understand airplanes and engines. When all other factors are the same, then the fan diameter=airplane fuel burn argument has technical merit. But for all things to be the same, the airframe and the engine core must have no differences. When JL says 1″ fan dia = 0.5% fuel burn, you can bet that number is very close to the truth when comparing a 77″ fan with a 78″ fan on the A320 with the LEAP-1B core. The difference in fan diameter does not have this simple relationship with airplane fuel burn when the wing, weight, thrust and core are all different.

  19. CM :
    I know you want the fan diameter argument to stick, but it only works for people who don’t understand airplanes and engines. When all other factors are the same, then the fan diameter=airplane fuel burn argument has technical merit.

    So it only works for people who don’t understand airplanes and engines?

    Are we supposed to think that your statement about fan diameter has itself technical merit? I will reluctantly answer yes, but only a little. You know as much as I do that if Boeing were in a position to increase the fan diameter they would. And you know as much as I do that they can’t.

    • I probably didn’t explain myself very well, but I think you are missing the point of my post, Normand. Yes, when all else is equal, the fan diameter argument is valid. That’s not the case in the A320 vs 737 discussion, which eliminates the possibility for there to be a 1:1 rule that works for the two airplanes. For example, If the A230neo has 10″ of additional fan diameter over the 737 MAX, there can be no rule of thumb to calculate the block fuel difference between the two airplanes using that information. It is, however, the argument JL, Keesje and others have been trying to promote; that an extra 10″ = a 5% fuel burn advantage for the A320neo.

      Now let’s talk about 737 MAX fan diameter. 737s operate with about 20% less installed thrust than the A320, so it stands to reason the 737 is not going to want the same engine as the A320. As noted above, the 737NG has the same core as CFM equipped A320ceo aircraft, but a reduced fan diameter. A quick comparison of the CFM56-5 versus the CFM56-7 shows that that the 737NG fan diameter was sized about right for the thrust difference with the A320:

      19% thrust difference between the two engines (33K vs 27K)
      20% fan area difference between the two engines (3632 vs 2922 sq. in)

      However, since the CFM56-7 core flow was sized for the thrust needs of the A320, the compromise reveals itself in the ratio between core and fan flow:

      CFM56-5 BPR = 5.9 : 1
      CFM56-7 BPR = 5.1 : 1

      The issue of using the other guy’s core will no longer be a compromise the 737 has to live with. The two aircraft, for the first time, will compete with the 737 using engines which are tailored to its requirements. If we assume the LEAP-1A engine is optimized (I have no reason to believe it’s not) we can use it as the baseline of what an uncompromised architecture looks like. When we compare The LEAP-1A’s relative sizing with the LEAP-1B, Boeing’s 69.4″ fan looks about right:

      19% thrust difference between the two engines (33K vs 27K)
      21% fan area difference between the two engines (4778 vs 3783 sq. in)**

      With CFM now creating a bespoke core for the LEAP-1B, I would expect the LEAP-1B BPR to be very similar to that of the LEAP-1A engine. If you believe the LEAP-1B core will be compromised in some way, I’d love to hear why.

      In my view, the LEAP-1B will not have the architectural compromises the CFM56-7 lives with today… an engine solution the 737NG seems to do OK with. As further anecdotal evidence that Boeing has no reason to further grow the 737 MAX fan, Boeing stated they have room to go up to 70″ or 71″ with the 8″ NLG extension. If we believed the JL/Keesje argument, Boeing would be foolish to leave the extra 0.5% – 1.5% fuel burn reduction on the table by not moving from 69.4″ up to 70″ or 71″. Since Boeing says they can do it, but yet they don’t, the argument it would greatly benefit them rings pretty hollow.

      • CM, why didn’t you tell Normand that you were comparing the installed maximum thrust on the 737-900ER with the installed maximum thrust for the A321, and not the maximum thrust differential between the 737-800 and the A320.

        The maximum installed thrust of the CFM56-7B27 engine on the 737-800 is 27,300 lbs.

        The maximum installed thrust of the CFM56-5B4 engine on the A320 is 27,000 lbs.

        http://www.cfm56.com/products/cfm56-5b/cfm56-5b-technology

        Hence your little thesis here is all fine and dandy, but not very accurate in respect to the “issue”, is it? 😉

  20. @OV-099. The reason I didn’t mention lower thrust ratings used because they are inconsequential to any inneffiencies related to the engine’s architecture. The lower thrust levels in the CFM-56-5 & -7 are achieved via thrust plug only. The core and fan dia don’t change when you derate the engine. All -5 engines are fundamentally sized for 33K thrust. All -7 engines are fundamentally sized for 27K. If there are efficiencies or inefficiencies related to architecture, they will exist at whatever thrust plug is used and at whatever thrust level is purchased for the engine.

    • I believe you are correct CM, that the 737MAX will be able to win a couple of percent due to the customised core, sizing for a thrust limit of 27 klb. But I have to agree with keesje and others that Boeing would obviously go for a bigger fan if they could. I mean, even the CS300 with only 23klb thrust has a fan almost 4 inches bigger than the MAX has. So lets not pretend that this 69 inch sweet spot is in any way an ideal outcome. It may be ideal, but only within the constraints Boeing is facing with the 1960s fuselage.

      And we might also ask why Airbus has the 33klb spec for the A321. Today, I believe, the 737-900ER needs 3100m to take off at ISA +15, whilst the A321 only needs 2100m. The lack of takeoff performance may be one reason therefore, for the ERs poor sales record. Seeing as Boeing shows the MAX needing about 800-1000kg more in added MWE compared the weight Airbus is adding to the ceo to make the neo, this situation will only get worse for the -9MAX.

      Bearing all this in mind, assuming Boeing continues on its current path, I can imagine a future in about 10 years times where clever airlines will be going for the Pratt engine and take CS100/300/A320neo/A321neo. The 737MAX will be more or less reduced to just the -8 variant, albeit with an engine running less time on wing and more stages to maintain when it comes off.

    • No, the CFM56-5B engine was not sized for 33,000 lb of thrust.

      As the A321 programme firmed up, it became obvious that the weight and payload requirements for the aircraft would require a higher baseline thrust. The -5B was therefore retargeted for certification at 31,5001b with offerings at two main ratings; a -5Bl at 30,000lb and a-5B2 at 31,000lb. CFMI also saw the chance to sharpen its competitive edge against the V2500, and made the new engine available for the A320 from late 1994 onwards. On the smaller aircraft, the engine was to be derated to 28,5001b thrust, with a common A320/A321 nacelle and pylon, offering significant take-off performance and lift-on-wing advantages.

      http://www.flightglobal.com/pdfarchive/view/1999/1999%20-%201413.html

      The CFM56-7B engine incorporated the -5B core and low-pressure turbine, but used a new smaller low-pressure compressor.

      The -5B4 engine on the A320 has a pressure ratio of 32.6, while all the -7B engines have pressure ratios of 32.8. To achieve the highest thrust levels reguired for the A321, CFM had to significantly increase the pressure ratio to 35.4 on the -5B1 (30,000lb thrust) and -5B2 (31,000lb thrust) engines and to 35.5 on the -5B3 (33,000lb thrust) engine.

      This means, of course, that the CFM56-5B engines on the A321 were more or less “custom-made” to the demanding requirements of the A321, and that the -5B engine for the A320 is not just a derated A321 engine.

  21. CM :
    I probably didn’t explain myself very well, but I think you are missing the point of my post, Normand.

    I love it when you get mad CM! 🙂
    It seems that it’s only when we provoke you that we get the best from you…

    I never subscribed to the direct rule of thumb of fan diameter versus SFC in the 737 versus A320 debate. But I firmly believed that the 737 MAX did not get the optimized fan diameter it required. And I always thought that the 737 would need more thrust than you specify because it was going to be heavier than the NG. But if the ratio of fan area and thrust remains the same for both engines (1A and 1B), then I have to admit that the 1B core should not have to be compromised.

    I have always been under the impression that the 1B core would have to be pushed to the limit in order to extract the targeted performance, and therefore would require exotic materials to sustain the purported temperature increase. That is what I meant by compromised core. But if your argument is valid, and I have no reason to think it’s not, then the 1B will be okay. And so will be the MAX I suppose.

    I only wish you had jumped into the discussion earlier with your latest point on fan area over thrust remaining proportionately constant between the 1A and 1B. Maybe you did and I failed to grasped its simple logic. But for sure this time around it strikes me as being quite hard to refute.

    That being said, the MAX still has to face the fact that it cannot accept an optimized P&W GTF engine, because the fan diameter would still be larger for that particular engine. Even if the 737 has some margin left for further nose gear extension. And that would give a decisive advantage to the A319/A320/A321 and CSeries CS300/CS500/CS700.

    Regards, Normand

  22. Normand Hamel :
    I love it when you get mad CM!

    Not mad, in this case, but certainly frustrated at the apparent effectiveness of an genius marketing gimmick which has no real technical merit.

    Normand Hamel :
    That being said, the MAX still has to face the fact that it cannot accept an optimized P&W GTF engine, because the fan diameter would still be larger for that particular engine.

    On this we agree. By my math, even the A320neo wants its GTF fan to be around 90″ in order to achieve the optimal BPR of the GTF engine, which is 14 : 1. The GTF on the A320neo is currently around 12 : 1, I believe. The 737 would want a GTF with about 20% less fan area, but that’s still a 80.5″ fan to meet 737 thrust requirements. There’s no way that could happen without new main gear on the 737 MAX.

    Normand Hamel :
    And that would give a decisive advantage to the A319/A320/A321 and CSeries CS300/CS500/CS700.
    Regards, Normand

    I may be dense, but where is this “decisive” A320neo advantage coming from? I can see the potential of a couple percent on fuel burn, but that’s not decisive… unless you are claiming the 737NG has a “decisive” advantage over the A320 today. The CSeries is a different story. It will be more fuel efficient than either the A320neo or 737 MAX, but fuel burn is not the only area an aircraft must compete. Never has this last fact been more evident than in Bombardier’s effort to break into the bottom of Airbus’ and Boeing’s market.

    Cheers!

    CM

    • Sorry, Normand, for making my comment appear as your quote 🙁 Not my intention at all.

      • Of course you were not mad. I was just joking and that’s why I put a smily at the end of the comment. But I found in the past that you tend to produce your most interesting comments when you have been piqued a little by our less informed comments.

    • It is true that the advantage should not be decisive initially. But later on, as the GTF is developed further and refined, it should eventually generate a “decisive” advantage for those who will be able to benefit from the latest iteration. And that is because the GTF has more potential than any LEAP engine will ever have.

      In regards to BPR, I believe the ratio is 12:1 for the CSeries and 11:1 for the neo.

      • For my friend the Beaver pilot, I have this to add: Think of the GTF as the 21st Century Wasp engine. 😉

  23. Normand Hamel :
    It is true that the advantage should not be decisive initially. But later on, as the GTF is developed further and refined, it should eventually generate a “decisive” advantage for those who will be able to benefit from the latest iteration. And that is because the GTF has more potential than any LEAP engine will ever have.
    In regards to BPR, I believe the ratio is 12:1 for the CSeries and 11:1 for the neo.

    You may be right about future PIP growth for the GTF. However, to get there, Pratt will need to increase OPR and temps. Their history with this is not great, as they have never demonstrated the ability to maintain reliability and on-wing life when pushing to the kinds of temps and pressures the other engine manufacturers operate at. In this regard, the partnership with Rolls may be a brilliant move for Pratt, as it will give them access to compressor, combustor and turbine technology which is significantly better than what Pratt has access to internally or through MTU.

    I would also add that CFM has a consistent track record of improving their own product over time. To believe they have somehow hit a cliff in terms of what they will be able to do with the LEAP engine going forward is to ignore a lot of history which argues otherwise.

    Normand Hamel :
    For my friend the Beaver pilot, I have this to add: Think of the GTF as the 21st Century Wasp engine.

    Indeed, the GTF will not be Pratt’s first innovative or enduring design. You won’t find me slighting the geared engine concept at all; architecturally, I think it is a brilliant design. In my opinion, geared engines will likely earn a place on any clean-sheet design going forward. Equally likely is that GE, CFM and Rolls will take a new look at the geared architecture for their own engines.

  24. Looking at order numbers, even the A319/737-700 seem to be less popular. NSA and whatever Airbus calls their replacement might just skip this size range as well, A320,321 and bigger, Boeing would have 738,739 and bigger. They would however have to make the new NBs really good as they have been outdone below 150 seats really. New players are growing upwards, A and B being so focused on their duopoly fight they might just be too late to respond to the market 10 years from now and end up with their pants down.

  25. Airbus will raise A320 production rates to 50 aircraft per month in early 2017 and to 60 by 2019. Boeing has committed to 52 aircraft per month with the capacity to go up to 60 as well. With an uncertain engine situation, availability could actually be more decisive a factor in neo versus MAX contests than the turbines beneath the wings.
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    And Happy New Year!

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