GE analysis post Farnborough

Our wrap up of Farnborough would be incomplete without looking closer at the world’s leading engine supplier, GE Aviation, which together with partners (like SAFRAN in CFM joint venture) garnered more than $36 Billion in orders and commitments during the show. This figure was only significantly bettered by Airbus ($75 Billion) and it came close to Boeing’s $40 Billion. With such level of business the claim by GE Aviation CEO, David Joyce, that the Airbus A330neo engine business was not the right thing for GE as they have more business than then they know what to do with, was certainly no case of “sour grapes”.

It starts with the follow-up business to one the world’s most successful Turbofan programs, the CFM56. The LEAP-1B continuous the exclusivity on the Boeing 737 with the 737MAX and the LEAP-1A has now over 50% of the orders for the Airbus A320neo. With the single aisle aircraft selling in record numbers this means CFM International captures about 75% of this the largest airliner market. It leads to deliveries of more than 1500 engines per year from 2017 from the joint venture. There is every possibility that the LEAP will pass the record of 25.000 engines delivered of the predecessor, CFM56.

LEAP features

LEAP features

The next program that is running well is the GEnx-1 for the Boeing 787. GEnx is now the leading engine with about 60% market share of the announced engine deals for the 787. Background is a 1-2 % advantage in the fuel consumption on longer missions over present Rolls Royce Trent 1000 variants. The GEnx-1 program has seen some initial problems, one which came as GE changed to a more environmentally friendly grease for the assembly of the engines (low pressure shaft cracking). These initial problems are now under control, the only remaining one to solve being a risk of core engine ice build-up when flying close to humid thunderstorm clouds. This will be solved with a new version of the engines FADEC control software which changes the way the bleed ports after the booster are opened during these conditions.

The top engine program, the GE90, designed for the Boeing 777 is also performing well. After a hesitant (for GE standards) start on the initial variants of the 777 the engine family has developed into a run-away success. GE achieved exclusivity for the stretch programs 777-300ER and -200LR in exchange for a considerable further development of the engine and part financing of Boeing’s development of the airplanes. This bold strategy meant further investments but it turned the GE90 program around, not the least because the GE90-110 and -115 over achieved set goals on several important parameters, the fuel consumption being one. This better than expected engine performance propelled the 777-300ER to a 7% overachievement in payload-range and laid the ground for the success of the variant.

Given this performance and the execution of the GE90 program it was no surprise that GE won the competition over Rolls Royce to be the exclusive engine supplier for Boeing’s new 777 variants, the 777-8X and -9X. The engine, GE9X, continuous GE’s tradition of further refining the direct-drive two shaft architecture, setting new performance standards for the individual components in the process.

GE9X cutaway

GE9X cutaway

Technologies behind the success

It is instructional to examine the technology of the GE9X to understand how GE has achieved its dominant position in the segments described. Starting from the front, the GE9X continuous GE90’s pedigree of offering higher By Pass Ratio (BPR) than the competition. GE90 was launched with BPR 9:1 when the competing Trent 800 and PW4000 were around 7:1. GE9X will now have a Take-Off BPR of 12:1 by virtue of an enormous 133.5’’ fan. To mitigate the weight impact of these large fans GE has gone to CFRP fans already 1995 with GE90 and followed up with a CFRP fan case from GEnx. The refinement for the GE9X is an even lower fan blade count, going from GE90’s 22 to 16 blades. This reduces fan blockage which leads to higher fan throughput at lower fan pressure ratios. A low fan pressure ratio gives a low specific thrust (see box) which is the premier measure of an engine with high propulsive efficiency.

Engine thrust is generated by giving air passing the engine a higher speed then surrounding air. This air over-speed multiplied with the air mass-flow through the engine gives the thrust. The lower the over-speed, the higher the propulsive efficiency and the lower the generated noise (but to keep thrust the mass-flow has to increase, hence high bypass ratios for turbofans). Engine people call the average over-speed “specific thrust”, it describes 1 to 1 the propulsive efficiency of the engine. High bypass ratio is a means to achieve low specific thrust, it is therefore not a measure for propulsive efficiency.

Following the fan GE is the industry leader in designing compressors with high pressure ratios. GE90 had the first compressor to pass a pressure ratio of 20 (23 from a 10 stage compressor) and the GE9X betters this record to 27:1 from 11 stages. The GE9X overall pressure ratio will be an unprecedented 61:1 from the combination of fan, booster and high pressure compressor. A high overall pressure ratio is the premier indicator of a high thermal efficiency for a gas turbine.

These compression stages requires a massive amount of shaft horsepower being passed through the two shafts from the back-end of the engine. GE is the leader in material technologies that allows high turbine temperatures and thereby high power output per turbine stage. It introduced CMC (Ceramic Matrix Composites) on the LEAP-1, starting with static parts (the turbine nozzle) and will follow up with more static parts on the GE9X. There were initial talks of employing CMC also on the rotating parts for the 9X (turbine blades) but it is now less clear if this will finally be the case. CMC has the advantage of requiring less cooling air to be tapped from the compressors to stay within acceptable temperatures and as all air tapped from the compressions side will reduce engine efficiency, CMC contributes to the low specific fuel consumption (SFC) for the engines. We also expect GE to start regulating the cooling air to the turbines for these new engines thereby gaining efficiency by virtue of throttling down the cooling flow at cruise power, a technique that Rolls Royce pioneered for civil turbofans on the Trent TXWB.

In our A330neo article covering the Trent 7000 we described the level of air being off-routed from the front part of the engine (up to 20% or more from all compressor parts and including the combustion chamber) for cooling purposes, we also described the weight challenges a direct drive two shaft architecture brings in this article. GE has consequently worked the weight challenge, in the front by employing CFRP for the fan 25 years ahead of its competition; in the rear by using lighter metallic alloys for the low pressure turbine. The low pressure turbines of modern direct drive turbofans are large and therefore heavy as they generate the power to drive 85-90% of the engines thrust trough the fan. At the low RPM that the fan dictates (through the fan blades max tip speed) the low pressure turbines have to be made with multiple large diameter stages (6 for GE90, 9X, 7 for GEnx), classically employing heavy nickel alloys to withstand the high temperatures. The GEnx was the first engine to employ lighter Ti Aluminide blades in the last stages, thereby reducing engine weight with 400 lb, a technique which is also employed on LEAP and GE9X. Through these measures GE engines have remained weight competitive despite the architectures propensity for higher weights.


Through excellence in the described technologies GE has built its position as the leading supplier of turbofans for civil airliners. That this will not continue unchallenged has been made clear by GE losing its market leading role in the small turbofan segment, where GE’s follow up to its successful CF34, NG34 has lost out to Pratt & Whitney’s Geared TurboFan (GTF) for new generations of regional and small single aisle aircraft. This is the first sign that GE and partner SNECMA will have to examine whether the time has come to upgrade the direct drive two shaft to a geared architecture. GE acquired Italian gear specialist AVIO last year, the manufacturer of the GTF gearbox, so there is vital knowledge in-house. Partner SNECMA is also conducting gearbox studies as part of its EU sponsored Clean Sky Open Rotor program, the question is which engine program will trigger going to a geared architecture; Open Rotor or a new ultra high by-pass turbofan for Boeing’s and Airbus new single aisle aircraft? With Boeing likely leading the race with a 757 replacing NSA, a new architecture could be presented from GE / CFM sooner than one think. Should Boeing launch a 757 replacement in the next years GE would certainly have to react and we don’t think an upgraded LEAP would be the answer, if for no other reason then environmental factors.

By Leeham Co EU

68 Comments on “GE analysis post Farnborough

  1. P&W and RR will work very hard on new engines for the Boeing NSA and nexgen NB from Airbus, what ever those airplanes turn out to be. As Scott wrote, GE already has a good head start on these new engine designs that will be required for the next NB airplanes.

  2. GE is sharing the 787 with RR, unvoluntairy absent on the A350 and A330NEO and will deliver to be developped GE9X’s from 2020. While hoping to sell as much as possible GE90’s on discounted 777s in the next 6 years.


    It think it is reasonable to conclude that in the 15-40klbs segment GE simply underestimated PW and its GTF technology. If that had known in 2008, they would have done things differently.

    • I think the market proves otherwise. They have so far beaten the GTF on narrowbodies, and it would be foolish to believe they are resting on their success. where’s RR on NBs? Nowhere, as they bailed out a while ago.

      Unvoluntarily absent on the A350 and A330Neo? Do you not read that GE basically said, “No thanks….market isn’t big enough for us to compete for business for A330 against RR against the development costs..” and the A350? I think they are doing just fine without it, being at 60% and growing on the 787, and exclusive on the 777X. The have a lot of business for a while.

    • If Rolls Royce by the end of the decade makes a deal with Airbus to develop a superior UltraFan engine for an A320neo Mk-2 with EIS in 2025**, then the production life-cycle of the LEAP-1A would IMJ be at risk of being severely curtailed. In all likelihood, GE is counting on the LEAP-X engines being competitive for at least 2 decades, not one just one decade.

      **UltraFan engine would have about a further 15 percent lower TSFC than the dead-end LEAP-X engines)

    • While hoping to sell as much as possible GE90’s on discounted 777s in the next 6 years.
      RR will be hoping to sell as much as possible Trent 7000 on discounted A330neo’s, for the life of the program.

      • The Trent-7000 will have a massive amount of commonality with the Trent-1000. Thus RR will be more than able to receive a very good ROI on their initial Trent-1000 investment as more than 2000 Trent-7000 engines might be produced . GE, on the other hand, will have a hard time recuperating their expenses on the GEnx-2B engine. Also, it’s highly likely that the combined Trent-1000/Trent-7000 production output will significantly exceed the total output of GEnx engines, by a significant margin. Hence, the decision by GE to “abandon” Airbus WBs will IMO go down in LCA history as one of the greatest strategic mistakes of all time.

        GE Aviation is said to be pushing Airbus hard to proceed with the neo, using the GEnx-2B engine now on the Boeing 747-8. The -2B is a bleed air engine, which the A330 requires, while the GEnx-1B used on the Boeing 787 is not. It’s been suggested to us by a source familiar with engines that the Airbus GEnx could be a combination of the 1B and 2B technology, however. Expanding the 2B engine to the A330 would be one way for GE to recoup its development expenses for the 2B, a problematic situation today with the slow-selling 747-8.

  3. Not involuntary. GE chose to absent itself from the A340, then chose to absent itself from the A350 (although that might be to do with non-compete clauses with Boeing) and now chose to absent itself from the A330neo. Since A and B have roughly half the wide-body market each, that’s an awful lot of absenting. It means one of a) GE has immense and fully justified confidence in its own ability b) GE is blindly arrogant and has misread its competitors c) GE is driven by short-term shareholder returns, not long-term strategy. Nothing is forever and GE is going to have to be very smart to stay top dog.

    • You do know the A-340-200/-300 had CFM-56-5C engines, exclusively?
      BTW, since 1980 Boeing has delivered 3,821 WB aircraft. Airbus has delivered 2,361 WBs. Since 2000 to 30 June 2014 Boeing delivered 1,551 WBs, Airbus in the same time period delivered 1,315 WBs. The market is not 50/50.

      • Your figures are historic once even the figures since 2000. You should look at the more recent 5 years and also at open orders and expected deliveries, e.g.:
        Looks nice for Boeing but the NEO is missing…

        The 787 production is getting close to 10 aircraft per month and there are still 20 small widebody B767 per year. By the end of 2014 the A350 will enter the market. Things will change.

        If you want to make Boeing feel great just compare the figures between 1960 and 1970.

      • The A340-200/300 were underpowered with the CFM-56 and as correctly said by arkay and Ge was not on the improved & re-engined -500/600, A and B have roughly half the wide-body market each (this does not mean an exact 50/50)

        • Yes, the A-342/3 were underpowered. But that was by choice by Airbus. They could have chosen to power the A-342/3 with PW-2037/-2040/-2043s or the RB-211-535C/Es. Both of these engines were available (they were on the B-757), could fit under the wing, and were more powerful than the CFM-56-5C.
          As far as the A-345/6 are concerned, there were only 131 of them sold and delivered. That is only 524 RR Trent-500 engines, plus spares. The Trent-500 series engines were essentially rehashed and upgraded RB-211 engines.
          Airbus had wanted GE to develop an engine for the A-345/6 in the mid 1990s, but changed their mind when GE wanted to be the exclusive engines for these A-340 models. Airbus said they wanted to offer optional engines. P&W offered an engine after that, so did RR. Airbus settled on the RR engine as the exclusive engine for the type.
          In retrospect, it is good GE did not develop an engine for the A-345/6, as the entire program never made a profit, and RR actually lost money on the deal.

  4. Looking at the next 10 years, GE will probably not be the top dog we used to know during the last 20 years. And that is not an opinion. The 737 line is cornered and market value shared in CFM. On the 320 NEO, LEAP dominance is not assured, to state it carefully. On the CEO the market is shared with AIE too, which dominates A321s.

    The 777X is late (a significant production gap is on the agenda & 777X sales slower then th hoped) and will mainly be a cost driver (development) in the next 6 years. The 787 is a fighting market with RR, with resulting margins. GE did aggresive proposals for the A350 and A330NEO but was shortlisted.

    On the regionals where the CF34 doninated during the last 25 yeras, PW has taken over on the Embraers, while GE missed out on the the CSeries and MRJ too. They are still on low selling the CRJ, ARJ though..

    Upbeat expectation are ok, they must be substantiated by more then past successes.

    • If Airbus decides to launch an all new mega twin family by the end of the decade**, using a cross section that allows for an 11-abreast seating configuration and 18 inch seats and 20 inch aisles, then IMJ the production life-cycle of 777X and the GE9X would be severely curtailed.

      **A360-800X using an all new 100,000 -115,000 lbs of thrust class Rolls Royce engine having at least a 5 percent lower TSFC than the GE9X (i.e. wing span of 80m and including 2 x 7.5m folding wingtips***). EIS in 2025. EIS of a re-engined A350-1000 using the same engine could occur in the following year, while the larger A360-900X and A360-1000X could enter into service later in the decade. A380-800 could IMJ be replaced in 2030 by an A390-800X/900X which would be twin-engine derivatives of the A380 (i.e. wing span: 95m and including 2 x 7.5m folding wingtips*** and an all new engine having around 140,000 lbs of thrust featuring a contra rotating fan in order to maintain sufficient bypass ratio).

      ***In fact, the outer portions of the wings on an A360X and an A390X could be designed with identical folding wingtips.

      • there you go again on the 18″ seat.

        the people who buy airplanes DO NOT CARE about 18″ seats. they only care about CASM, Trip costs, capital costs, maintenance costs and resale values. i.e. dollars, cashola, semolians, lucre, filthy filthy lucre.

        the people who buy tickets (as a rule) only care/know about ticket cost, and might remember that last time they flew on X airline, their knees were in their chest. all coach seats are too narrow, so they are always uncomfortable on shoulder room and sitting next to a fat/big shouldered person is going to be unpleasant.

        18″ seats are not a differentiator to customers. seat pitch is.

        • The point here was 11 across, not the 18 inch seat. The smallest model of an all new A360X mega twin family would be slightly shorter than the 777-9X, have about the same MTOW , but carry a significant number of extra seats. Designing it to cater to both ample aisle space — 20 inches instead of the 17 inches that’s the standard on the 777 at 10 across — and 18 inch seats and 2 inch armrests, won’t make the cross-section that much bigger.

          As for the 18 inch seat — or wider, all the other new single aisle programmes do have that seating standard. Only Boeing, it sees, is stuck in the 1960s.

        • OV, increasing the crossection diameter by 36″ from 20′ 4″ to 23′ 4″ to get those wider seats and aisles will increase cross sectional area by 31.6% in exchange for a 10% increase in passenger capacity for the same length aircraft.

          given that the 777 already has a ton of dead space in the crown and under the cargo bay, how is this economical?

        • Delta uses 17.2″ seats on their A320s, I guess they’re stuck in the 1960s too.

        • “Delta uses 17.2″ seats on their A320s, I guess they’re stuck in the 1960s too.”

          No, Delta is not stuck in the 1960s.

          17.2″ wide seat bottoms and 2″ wide armrests would mean that the aisle is 26″ wide. Some operators like the extra cabin width used in the aisle as this allows for greater speed in boarding/deboarding as it is far easier to pass than the far more cramped 737 aisle.

        • That aircraft could be called A350-1100 “Advance” and could enter the market advance to the 777X. In my humble opinion the X will be the next 8i.

          • Right now there is no A-350-1100, so a model named “-1100-ADVANCED” isn’t in the cards for a long time from now.

        • You got that wrong. The A350 is not a budget and schedule busting programme like the 787, and the Dreamliner R&D cost overruns seem to far exceed those for the A380.

          Well, the A350-1000 already competes with the 777-9X.

          Since Airbus only has to spend a relatively insignificant amount of resources on the A330neo, they will be quite well positioned to launch a mega twin programme in 2017/2018. Boeing, on the other hand is spending upwards of $10 billion on the 777X, or more than half the amount of what would be required for an all new 777 successor aircraft. IMJ, this is a strategic mistake on the part of Boeing. The 777X may look good today, but possibly not so good at EIS.

        • Dear KC,
          just because there is no name for something the possibility is not zero for something to happen. Airbus has enough engineering resources to build a simple stretch of the A350-1000 between 2017 and 2020.

          We have seen this month that Airbus is not deaf and can hear what costumers demand.

          In my opinion the 777X and the A350-1100 are both linked to better engines – GE9X and RR “Advance”. With a better engine an A350-1100 would require a minimum design change in comparison to the -1000 to keep the range.

          New tricks for old aircraft are not so cheap to realize:

          • I agree, but there have been many proposed derivatives of airplane models that never went anywhere. The A-330-100/-500/-200LITE/-300HGW, Sonic Cruiser, A-380-800F/-900, B-767-400ERX, and the B-747-500/-600/-700 all come to mind.

            Thanks for the update on the wiring harnesses on the KC-46, but this has been known for a few months now. Boeing took the $272M charge off in the last quarterly report.

    • Seems like comments are made without having read the article they are attached to. PW can only reach parity with GE if neo gets 70% vs max and PW gets 70% of the neo, well beyond even the most recent numbers. In TA, even if market share flips completely from now and RR dominates, GE still is much larger than either competior. The regionals is probably a small enough market to not be a major threat.
      As Scott points out, the competitive advantages of superior materials compliments UDF or GTF, whereas the GTF reduces the advantage of the 3 shaft RR design. Another point he makes is that GE met or beat performance goals on both 787 and 777, RR did not. PW had significant problems with its TA engines in the past, time will tell how well it does in the future but it is climbing out of a decade of low performance in commercial.

      • It amazing how some people can read the article and then try to spin it as bad news for GE.

        • It’s puzzling why some people feel the need to resort to ad hominem attacks (i.e. sore loser statement).

          As for the article, please keep in mind that this is an industry where long term strategic planning is much more important than the short-term focus by shareholders on quarterly earnings which can impair on firms’ ability to create long-term value.

        • So are you saying that GE is focused on the short-term quarterly earnings, instead of creating long-term value?

          If not, what are you saying?

        • You’re missing the point. See In 1995, GE dominated A’s WB market. By 2020, with the A330neo in full swing and the A380neo launched, RR will have almost all of A’s WB market. With 40% of B’s 787 market as well, RR is then the world’s dominant supplier of WB engines. How did that happen? Did the Head of Strategic Marketing at GE do a Powerpoint presentation in 1995 saying “our long term strategy is to cede one of our two major civil markets to our weakest competitor?”. FlightGlobal makes it clear that at each point along the road, GE didn’t fight a great battle and failed to win the day; GE didn’t fight at all because they didn’t think any of the battles were worth fighting. So how did GE come to make those decisions and end up where it has?

          BTW, the article above isn’t bad news for GE. It just says how wonderful GE is. But it only addresses the areas where GE is wonderful.

      • My understanding is the the 787 engines (R&R and GE) are not meeting the performance goals EVEN TODAY!!!

  5. I have a great respect for GE, although my area is diesels and steam turbines.
    Have no issues with believing that GE LEAP 1 will deliver on the NEO airframe, but I have difficulty in believing a scaled down version can do as good a job on the MAX.
    It has a lower by pass ratio, and a seriously smaller fan diameter.
    A competitive fuel consumption and comparable noise levels to LEAP 1 seem a trifle optimistic IMHO.

      • Why did Airbus bother with the big heavy fan if both engine sizes are equally fuel efficient? Couldn’t they have gone with the MAX sized engine instead?

        • Actually, the A320 requires a slightly higher trust engines (about 4000 LB more), so it is the 737NG that was carrying as somewhat heavier engine with the same core size as the A320.

        • “lighter 737” is a red herring.
          Last time OEW weights were published they seemed to be on par ( but delta in seat numbers ) .
          A320 has across the family significantly better take off performance. Probably in proportion to the “slight” thrust advantage and some more.
          A320NEO engines versus the 737MAX engines show a difference in efficiency and not in weight.(MAX will be even more underpowered in comparison.)

  6. You never give your competitors and inch, big mistake to let RR run wild.

    Thats how you wind up out of the bussiness.

    • Well, as I read this for the WB market, RR currently has 77% of the A market, see When the A380neo eventually happens, GE will absent itself again (it’s already said that) and RR’s share of A will be over 90% in the 2020-2030 decade. With 40% of B’s 787 business as well, that makes RR the dominant WB engine supplier.

      In NB it’s quite different. RR’s 3-shaft architecture doesn’t scale down well and they have no current place. GE’s 2-shaft architecture is running out of steam. So both RR and GE will approach from opposite ends and go to a 2.5-shaft for the next generation of NB engines. For 2.5-shaft, read GTF, a la P&W. So there will be three, essentially identical, engines fighting for the 2020-2030 NB engine selections. Who will win? No idea. Probably all three because no-one will walk away from this market and no-one will invest $2-3Bn in an engine development and then let it achieve zero orders. But if the market splits three equal ways, GE gets only half the economic value of its share, whereas RR and P&W get 100% of theirs.

      Whichever way it goes, GE does not look like the future dominant force in civil airliner engines.

  7. “OV, increasing the crossection diameter by 36″ from 20′ 4″ to 23′ 4″
    to get those wider seats and aisles will increase cross sectional area
    by 31.6% in exchange for a 10% increase in passenger capacity for the
    same length aircraft.”

    I’m sorry, but your numbers are all wrong, but your percentage increase
    in cross-sectional area is about right.

    Also, please keep in mind that an internal width of 266″ allows for a
    business class section with three aisles and direct aisle access from
    every seat and where only the outboard seats would be staggered.

    10 abreast with 18 inch seat bottom widths + 2 inch armrests + 2 x 20
    inch wide aisles = 246″ = 20′ 6″

    11 abreast with 18 inch seat bottom widths + 2 inch armrests + 2 x 20
    inch wide aisles = 266″ + = 22′ 2″

    777 internal width: 231″ = 19′ 3″
    777X internal width: 235″ = 19′ 7″

    Sure, the internal volume of a fuselage grows faster than its surface
    area (square-cube law), but you’ve got to think about its fineness ratio
    as well. Slender fuselages in large aircraft with a fineness ratio of
    12-15, may well involve stiffness problems, and they would require
    additional stiffening (i.e. increase in OEW). The slenderness ratio for
    the 777-9X is much less favourable than what would be the case for a
    slightly shorter A360-800X mega twin.

    Here are the fineness ratios for A346, A350-1000, 77W and 777-9X

    NB: Fuselage length is not identical to overall length.

    _______________l-F/d*-F_______Fineness Ratio


    *External diameter in meters

    “given that the 777 already has a ton of dead space in the crown and
    under the cargo bay, how is this economical?”

    The “dead space in the crown” doesn’t have much mass, does it? 😉

    Now, if the crown has enough useful internal height (i.e. standing
    height not infringing on the cabin below, then you could, for example,
    move quite a few of the lavatories , and even a galley, upstairs around
    doors 2 and 4; or similar to how Lufthansa has located lavatories and a
    galley downstairs on their A340-600 fleet. Neither the 747 (i.e. aft
    fuselage) and 777 have sufficient standing room in the crown to accommodate
    lavatories, although the 747 crown could conceivably be outfitted with a
    galley-cart stowage system.

    • Addendum

      2.7 The Slenderness Parameter

      The slenderness parameter (also called fineness ratio) is given by
      the length of the fuselage divided by the fuselage diameter

      (13) Lambda F = length-F / diameter-F (l-F/d-F)

      According to own statistics, the value of the slenderness for
      today’s aircraft is about 10.3. This parameter is a key parameter in
      aircraft design, respectively aircraft cabin design. If the aircraft is
      too short (with a small slenderness), then the empennage surface
      increases, due to the short lever arm. On the contrary, a long fuselage
      means a high wetted area and, accordingly, high drag. This
      interdependency represents for this paper the core of the optimization

    • What is an A360 in your eyes? A single deck aircraft or an A380 with two passengers decks but with just 1 big engine under each wing?

      I have the feeling the A350 is close to the right size for a single deck aircraft while the 777 is slightly to wide. A slightly larger aircraft should have a additional passenger deck just like the A380.

      • By 2030, would it be possible to have the necessary technology to develop a twin engined derivative of the A380?

      • A 9 frame stretch of the A350-1000 will not have a very favorable fineness ratio** (e.g. 13.08), although it would have a composite fuselage. Also, the wheelbase, or landing gear footprint would be significantly larger on an A350-1100 than it’s on the 777-9X.

        One reason IMJ that the 777-9X is going to quite heavy is that its fineness ratio is borderline and that the fuselage will still be made out of alumnium materials that have less strength and stiffness than composites. The A330-900neo, on the other hand, has a fineness ratio of 11.14 which is much more favourable for keeping an alumnium fuselage light.

        The fuselage of an A360X should IMO have an external diameter of about 7 meters. In a single deck configuration, the fuselage would have enough standing height in the crown in order to allow for some lavatory and galley facilities to be located upstairs, but only in areas above doors 2 and 4 (i.e. assuming 10 doors overall).

        If the A360X fuselage would have the same external dimensions below the main deck as that of the A380 fuselage, then you could develop an A370X family concurrently with the A360X. They would both have the same wing (80m span) and engines, MLG as well as most sub-systems.The A370X would use the same fuselage as that of the A380, and would be optimised for intermediate range. Hence, an A360X/A370X would be similar in scope as that of the original A330/A340 programme.

        Now, an A390X would be a twin-engined version of the A388 (-/A389) but would not EIS until 2030, at the earliest.

        **_______________l-F/d-F_______Fineness Ratio


    • OV, the numbers I used were based on external diameter and going from 10 17″ seats and 17″ aisles to 11 18 inch seats and 20″ aisles as proposed in your first post.

      The 31% increase in cross sectional area for a 10% increase in seats was not about fineness ratio, but purely about aerodynamic drag, of which cross sectional area is a major factor, additionally wetted area, another major drag factor, would increase by 15%.

      dead space doesn’t weigh much, but is cross sectional area and thus drag that serves no functional benefit.

      belly space in excess of that needed for side by side LD3s is not terribly useful until you get to 3 wide LD3s, so in this case, the added length of the 777 is useful in that it provides more LD3 spots.

      • “OV, the numbers I used were based on external diameter and going from 10 17″ seats and 17″ aisles to 11 18 inch seats and 20″ aisles as proposed in your first post.”


        “The 31% increase in cross sectional area for a 10% increase in seats was not about fineness ratio, but purely about aerodynamic drag, of which cross sectional area is a major factor, additionally wetted area, another major drag factor, would increase by 15%.”

        There’s no need to confuse people. Again, the internal volume of a fuselage grows faster than its surface area (square-cube law), thus the wetted area increases linearly. A single deck A360X at 11 abreast and 20″ aisles would have about a 13 percent larger diameter than the 777X, however it would be optimised around the base model A360-900X having a fuselage length of around 80 m. Hence, the wetted area would be in the neighborhood of 25 percent larger.

        Now, the longer cabin would have 5 more economy class seat-rows than the 777-9X; or 55 seats. In addition you’d have one more seat than the 777-9X passenger seat rows; or 30 + seats. Then, by moving economy class lavatory facilities upstairs above doors 4 and maintaining the cabin width almost all the way to doors 5, you could keep the 11 abreast configuration all the way back to doors 5 (i.e. no lavatories forward of doors 5). That’s another 20 + seats right there as the 10 abreast configuration of the 777-9X will have to be reduced to 8 abreast in the last 5 rows (i.e. assuming no lavatories ahead of doors 5).

        So, what do we have, then. 105 more economy class seats than the 777-9X and up to 10 more business class seats (i.e. for the same cabin length) at 8 abreast and three aisles: 2-2-2-2 with the outboard business class seats being in a staggered configuration. That’s about 30 percent more seats on an A360-900X than the 777-9X, which would seem to indicate that a 7 m wide fuselage barrel starts to get more efficient than the uncomfortable 10 abreast 777X barrel for fuselage lengths above 78-80 m.

        Now, what I was actually talking about was the strength and stiffness of a fuselage. If a fuselage cylinder is getting longer and longer, it will tend to bend downwards. In order to maintain buckling resistance, you would need to add internal reinforcements (i.e weight). Thus, a longer fuselage cylinder of a set diameter needs more weight to keep it straight — and you’re probably aware of the fact that a composite fuselage inherently has more stiffness than an aluminium one.

        “belly space in excess of that needed for side by side LD3s is not terribly useful until you get to 3 wide LD3s, so in this case, the added length of the 777 is useful in that it provides more LD3 spots.”

        Again, the lower fuselage below the main deck of an A360X could be designed to be very similar to the lower fuselage on the A380. So, we’re not talking about “3 wide LD3s”.

        Now, by designing for maximum commonality with the A370X/A390X, a modified A380 cockpit section could be used on the A360X as well. The raised cockpit position should be able to be integrated into an A360X fuselage due to the significantly increased fuselage height of an A360X. Of course, the cockpit roof on an A360X would have less tapering than what’s the case on the A380.

        Finally, a shorter A360-800X would be a URL derivative — possibly having sleeping accommodations upstairs along most of the length of the pressurised cabin. Also, a stretched A350-1100 and A350-1200 could use a modified version of the A360X wing, but with the wing area reduced in chord and span.

  8. Does a fuselage have to be round? A horizontally arranged, slightly oval cross-section would give more seating area without increasing wasted space in the crown and still be strong from a pressurisation point of view

  9. This reached LOL status when discussion touched a A380 lower fuselage twin. There won’t be another vla twin aluminum derivative. The next moves will be irregular shaped (ovoid) carbon barrels. The debate about what the “ideal” width/ratios will be going on after all of us posting today are long deceased.

    • There will be a need for VLAs with 500+ seats in the coming decades but I don’t think it would be in numbers that warrant an expensive all new aircraft development program. An A380 based derivative may be the most you can ever justify.

  10. “Through these measures GE engines have remained weight competitive despite the architectures propensity for higher weights”

    These measures makes the engine weight competitive at the expense of extra cost, and the majority of them can be applied as well to other architectures.

  11. Agreed, actually with the GTF using those materials would give you a double upside.

    As for the 757, there seems to be people stuck on it, but the market is not there (at least in the current form).

    While its a repeat, the vast majority of that market (lower end) has been picked off. Upper end is minimal.

    Boeing needs a 737RS, not a 757.

    It needs a direct range competitor to the A330NEO (787-8 or 9 or both with a new wing and possibly GTF engines)

    P&W should be in the lead with the GTF as they have the experience that no one else has (both for 737RS and the A330 competitor as they have studied scaling the existing GTF up) Yes you can prototype it (RR and GE), but having numbers on wings and getting the feedback as to how it all worked is the key to a mature engine.

    Keep in mind P&W really is not P&W, its really MTU and Japans consortium (if they choose to use them), so they have some heavy chops both capability wise as well as production capability

  12. Boeing should be looking at a 737/757 replacement design centered on 737-9/a321 passenger capacity, with a modular center wing box/inner wing/pylon/landing gear complex designed to be delivered in LGW and HGW versions and a modular outer wing that comes in C gate and D gate sizes.

    -8 -9 -10 LGW/C-gate for domestic hub and spokers (~2000 mile range)
    -8 -9 HGW/C-gate for domestic point to pointers/icelandair (~3200 mile range)
    -9 -10 HGW/D-gate for transatlatic/long thin (~5-6000 mile range)
    -8 HGW/D-gate for BBJ (7k+ range)

    combine that with a PIP’d PW1100 for LGW and a 40-45klb GTF+ for HGW and you have covered the single aisle mainliner market

    • oh, and throw in 19″ seat bottoms and a 24″ aisle. that would really mess with the Airbus fanbois…. 🙂

      • not sure how you propose saving 15% weight over the LGW/C-gate version. the majority of weight difference between a short range aircraft and a long range one is not in the fuselage, but in the wingbox/landing gear/pylons and engines.

        • so, basically a bombardier C series or Embraer 195E2? Despite the statistics you show (and there are similar statistics at the mid-size widebody level where average segment length is 2kmiles or less) the current state of both products (and medium widebodies) shows that the airlines want and are willing to pay for the ability to use their narrowbodies on relatively long (6-7 hr) legs (and medium widebodies on 10-12 hr legs).

          clearly Airbus’s biggest area of advantage over the 737 is in the -9/A321 space, they are both equally uncompetitive at the -7/A319 space vs the BBD/EMB products.

          to compete with the EMB/BBD products, Airbus would have to commit to a clean sheet design in an area of the market where margins are even thinner than they are for their current product line, which seems to me to be an unlikely proposition.

          btw, I think the next place you are going to see major technological innovation in search of weight is in the use of composites for main members in the landing gear. there is just too much dead iron being hauled around for that not to become a juicy target.

        • addendum – looking at that chart you provided I can’t help but notice that it is largely governed by the capabilities of the existing fleet, both in seat capacity requirements and in range. there are huge spikes at the 150 seat and 189 seat levels, which line up nicely with the sizes of the existing airframes, and there are a tremendous number of older A320s and early 737NGs out there with max ranges that make legs much longer than 2K uneconomic or unreliable for range/payload restriction reasons.

    • I think both A & B see the market for 180-250 seat aircraft (which is much larger then just 757 replacement of course). IMO can fix it with an A322 for ~3-4 billion, mainly investing in 10-20% larger wing (Lift, fuel). The LEAPX and PW GTF can go up to 40k lbs.

      Boeing going there with a 737 replacing NSA risk them at risk at the 150-160 seat <1500NM segment. A CS500 or something new from Toulouse would capturing most of the sales.

      A concept I (Great graphics by Henry Lam) promoted a decade ago was an aircraft focussed at 120-160 seats, Large Regional Jet. It would splitting the current NB segment in two, a lighter super efficient city hopper and larger high capacity range platform.

      1 Airframe fits all was a good idea when fuelprice was low and stable and the market 3 times as small as today.

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