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Matt6461
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2025ish A380-900NEO

Mon Jan 22, 2018 5:28 am

Given the recent EK order, it looks like Airbus has a production bridge to an A380NEO that uses Ultrafan or similar engines, should a business case arise. So will it? Obviously the answer to that question depends, in part, on the economics of an Ultrafan NEO. So I'll take a shot at seeing what seems possible.


Summary of Argument: A 2025 A380-900NEO with large winglets, a revised empennage, A380Plus-style cabin modifications, and perhaps other features seems capable of 35+% per-pax fuel burn reduction, possible trip savings on maintenance and fees, and overall 20+% CASM improvement. The emergence of low-cost longhaul competition to legacy carriers, combined with general traffic increases, could result in a NEO that sells 30-45 frames per year and generates Airbus profits sufficient for ~$3bn investment.

[a.net aside for members: I remain no fan of the A388, still believe it was a waste of opportunity and investment. While I've previously written about VLA futures that involved rewinging the A380 (for ~2021) or its early death so a clean-sheet replacement could be built, it now appears that neither will happen. The best path forward seems Airbus success with an A380NEO. So feel free to think of this post as, "how matt became an A380(NEO) fanboy."].

My standard disclaimers apply: I'm not a professional, I'll be applying basic calculations to the dominant drag/weight calculations, anybody who can do this better or suggest revisions is welcome. I know a little more at the beginning of this thread than I did at the last; hopefully that trend continues.
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Summary of analyzed A380-900NEO features:
  • Stretch by 31ft to fuselage length of 262ft/80m, incorporation of A380Plus cabin modifications and UD door revisions
  • Smaller, lighter empennage due to longer lever arm and other factors
  • 21ft tall (up+down) scimitar-style winglets, increasing effective span to 290ft
  • Engines of Ultrafan generation, contributing 17.5% lower SFC than T900
  • "Internal widening" a la 777X to accommodate 11ab seating (not essential but seems beneficial/feasible)
  • Possible changes not analyzed: Use of Al-Li, modification of landing gear

Each of these proposed changes requires approximations/assumptions and each interacts with the others, so it's not entirely right to analyze them in isolation. But you have to start somewhere, and I don't want to narrate 100 iterative estimation loops. The following are the components of my estimate settling on ~1,200,000lbs MTOW and slightly weaker engines than the current A388.

Section 1: Capacity enhancements, fuselage weight and wetted area implications

A stretched NEO should fully occupy the 80m box by adding 31ft of fuselage length to reach 262ft. Empennage changes discussed below should keep LOA acceptable.

Deltas:
  • Cabin area added: 31ft * (248in + 208in) = 1,178ft2, 109.4m2
  • Fuselage wetted area added [assume 25.8ft diameter]: 31*pi*25.8 = 2,512.6ft2; 233.4m2
  • Cabin area increases by ~20.1% (over 545m2), fuse Swet by ~14.9% (over 1564m2)
  • Assuming A380 Fuse weight (tube-only) is 150,000lbs, and assuming [see note 1] linear escalation with wetted area plus "fudge factor", fuselage weight delta is ~22,400lbs + 4,000lbs = 26,400.
  • Delta to floor beams @6lbs/ft2 = ~7,000lbs
  • Delta to buyer-furnished equipment (BFE), at 60lbs/pax = ~6,000lbs
  • Internal widening weight delta: ~2,000lbs (discussed below)
  • Total fuselage weight delta to OEW: ~41,000lbs
Note 1: The assumption of linear escalation with wetted area wouldn't be valid for any simple stretch, as increasing fineness ratio increases reinforcement needs. I added a 4,000lb "fudge factor" for fuselage reinforcement. Anyone have a better idea how much fudge to add here? I can explain how I got to that but...

Internal widening would occur by narrowing the frame depth on only the lower ~3ft of the MD: ~7.5% of the fuselage circumference. We only want to increase width at seat/armrest level. Actually the "cut" would be gradual from below max cabin width at 258in (eye-level), starting from cabin width of 256in and increasing gradually to 4in (on both sides) down to the floor beams.

  • A 33% decrease from the A380's 12in sidewalls would add 8in of cabin width. Enough for a humane 11-abreast (747/777X space standard).
  • On basic structural engineering principles, a 33% narrower frame would require 50% more material for equal strength
  • Adding 50% to 7.5% of current frame material = 3.75% increase in frame weight
  • If frames are 30% of fuselage weight (probably too high), we get 1.125% delta Fuse weight = 1,687.5lbs.

Let's call it 2,000lbs. Seem reasonable? I haven't seen reports that the 777X gained much weight from its sidewall sculpting, which was ~same proportion as this proposal but for a bigger relative portion of fuse diameter. Potential obstacle could be what's in the sidewalls there - would Airbus need to rewire things going through the frames at the proposed point? Idk but that could get ugly... Nonethless they're using only one design software module now (hopefully).

So what's our total capacity delta? Let's start with EK's latest version of the A380 MD seating 437 pax:

Image

Then let's add:
  • 30 seats for 11ab
  • 14 seats for the aft galley/stairs module. Image

  • 12 seats for front stairs removal, combined captain/crew rest entrance (Airbus says 20 seats but that includes impact on UD, and EK's 2-class layout already has lavs where crew rest usually is): Image

  • 132 seats in 12 rows@31in pitch due to the stretch
  • then let's subtract 15% of added seats for galleys/lavs (10 pax/cart, ~.6seat/cart; ~45pax/lav, 2.5seats/lav)
  • total seat delta is 160 Y seats

That would give us 597 seats on the MD, probably illegal given our 5 MD exit pairs. So make it 550 seats with 240 Y+ seats, 10ab@35in pitch; 310 Y- seats, 11ab@31in (calculated as Y+ = 1.25*Y-) We now have a good mix of Y+ and Y-, more on that later. Nominally that's a ~26% increase in MD capacity.

On the UD, I'd delete Door 8 (as proposed for A380Plus) and add a door at the front. That enables seating forward, in absence of grand staircase. So we have 31ft extra space from the stretch, plus the foward staircase/lavs area is more useful.

LOPA example:
Let's devote the extra UD space to 9 rows of PY, 7ab@38in. Behind that goes, say, SQ's new UD: 6 F seats, 78 J. That would give us 704 seats (310 Y-, 240Y+, 63 PY, 78J, 6F).

Section 2: Wing enhancement via winglets

IMJ an A380NEO should use the most aggressive deployment of winglets yet seen on an airliner. It has the lowest-AR wing in production and can benefit disproportionately from winglets.
For the A380Plus, Airbus proposed 15ft winglets for 4% fuel burn improvement. IIRC Airbus said the winglets used untapped structural margin (no skin/stringer strengthening for increased bending moment). I couldn't find the direct quote (can anyone?).
On a -900NEO, Airbus would have to beef up the wing anyway, so adding increased bending stress due to effective wingspan gain makes sense.
I'd propose 21ft winglets (bigger seems better but IDK the practical limit). Following the rule of thumb that one gains 2/3 effective span per unit of winglet height, this would increase effective span to 290ft (from current ~267ft per Ferpe/Bjorn).
The 8.6% span increase would cut induced drag by 15%.

Weight delta: let's hold off on this until the end, as bending moment involves fuse/empennage/payload weight as well.

Section 3: Empennage

The A380's empennage's area is 654m2 - 91% of one wing's exposed area. http://www.fzt.haw-hamburg.de/pers/Scho ... _A380.pdf( page 38).
By contrast, the similarly-stubby B788's empennage is only 66% of wing's area: 28% less.

What explains the abnormally large empennage, even relative to the abnormally large wing?:

  • Airbus imposed a very low approach-speed constraint (140knots at MLW). Wing Cl is likely highest on approach, the low speed necessitated a huge H-stab sufficient to generate stabilizing/maneuver lift at these low speeds. IMJ this noise benefit is too low to justify the weight/drag expense. Faster-landing planes like 77W don't appear to suffer much, if any, market hit. In any event, the new engines will greatly reduce total vehicle noise. A 10% higher MLW approach speed (154 knots) should allow H-stab area reduction by ~Shstab/1.21.
  • Airbus envisioned the A380F entering service shortly after the A388 and finally cancelled it only long after A380 EIS. Airbus did not, AFAIK, plan to build a separate empennage for it. The A380F would have had MLW significantly greater than A388, higher MTOW (~600t), and significantly higher thrust (at least 78k, RR certified up to 84k). These factors would have required greater tail volume; the A388 likely carries that burden now.
  • A380's hardware stability design lags the state of the art, as one would expect for an older design. More recent planes like E2 series use advanced FBW to enable lower stability margin (and longer lever arm for given fuselage); the A350 has a good wing/empennage ratio. I've read that Airbus revisions to FBW laws have all but eliminated the A380's trim drag, but it can't shrink the Hstab with clever code.
  • Relatively short lever arm compared to LOA

With these parameters in mind, we can posit a new empennage as follows:
  • H/V-stab area decreases according to lever arm length (L), measured by distance between the wing's center of pressure and the stabilizer's center of pressure. On the A388, I estimate L at 110ft. This is less than half of LOA, but very-long chords mean that the CP's are farther aft (wing) and forward (stabilizers). 110 is probably a bit high, actually. I posit an 18ft stretch to rear fuse and 13ft stretch to forward fuse. Our relaxed stability margin and lighter empennage should keep the CoG similar or slightly shifted aft despite the fuselage imbalance. [This is an iterative calculation with the empennage parameters]. Accordingly, the lever arm grows by 18/110 = 16.4%.
  • H-stab area decreases by 10% for a "Modern FBW" technology factor.
  • H-stab area decreases by up to 17%, given our higher minimum approach speed.
  • V-stab area related to engine thrust / 84k lbs (max freighter thrust). I'll use 68k thrust here, as we'll end up with lower MTOW (iterative calculation)

Calculations:
  • A388 H-stab has 410m2 exposed area (~420m2 wetted, after accounting for camber).
  • A389 H-stab modeled at 264m2 = 410 / 1.2 * .9 / 1.164
  • A388 V-stab has 244m2 exposed area (~250m2 wetted area)
  • A389 V-stab has 175m2 exposed area = 244 / 1.16 * (68/84)
  • Total empennage exposed area decreased by 33% to 439m2

A few observations:
-This is a big reduction in empennage size, but we'd still have the biggest empennage by far (~60% bigger than 777-9's H-stab, 80% bigger than 777-9's V-stab).
-I've assumed that the stabilizer's pressure centers didn't move here. That assumption allows us to stay within the 80m box by not overhanging the rear of the fuselage. I'd guess, however, that it would be ok for stabilizers to go a ~5ft past the box, which would allow for a longer lever arm.

Weight implications:
-I've seen typical empennage weight estimates ranging up to 10% of OEW. Whatever the truth, A380 would be at upper end of the range. Most likely the higher estimates include much of empty tail cone in addition to stabilizers.
-I'm going to model the empennage weight delta as (proportional exposed area delta) * 40,000lbs. This seems a compromise between a high estimate and one that ignores all but the stabilizers. The lower lift forces created would mean lighter actuation machinery and less structural stress on the rear fuselage. We're not rebuilding the whole rear fuselage but load/stress paths will necessarily be adjusted during a stretch, and we can harvest some of that via empennage adjustments. Insofar as stabilizers are "wings" that follow square/cube principles, linear weight/area relationship is actually conservative.
-Empennage weight delta = .33 * 40,000 = ~13,000lbs

Section 4: The engines.

I assume we'll use Ultrafan engines or a similarly-good PW/GE product.
Per RR, Ultrafan will have at least 25% lower SFC than original Trent, while the Advance (if built) will show 20% improvement. Ultrafan therefore should show 6.25% lower SFC (.75/.80)
Per Leeham, RR Advance would have 12% lower SFC than T900/GP7200:

Image

So let's say Ultrafan will have 82.5% of the current A388's SFC. [.88 * .9375]

How much thrust do we need? For simplicity's sake let's keep the same T/W as the A388. I calculate below that A389NEO's MTOW should be ~1,200,000lbs. Again, this is an iterative calculation interdependent with our fuselage/empennage weights and Swet's.

The GP7200 and T900 at 72k lbs-T have low thrust/weight ratios and a lot of wetted area relative to thrust. The GEnx/T1000, for example, have lower dry weight, less nacelle Swet, and greater max thrust. Plainly the A388 is carrying bigger, heavier engines meant for the -900 and -800F. Luckily this version won't need more thrust.

RR also plan a shortened core and nacelle for Ultrafan. So despite the higher-BPR and probably slightly-larger fan diameter, I'd expect total engine Swet to be about equal.
Ultrafan shouldn't (IMJ) be heavier per lb-T than current engines: most weight is in the core, which will be shorter, while the larger fan blades will be of advanced material. Assuming 5.5 lbs / lb-T, a 68k Ultrafan engine should weigh ~12,400lbs - ~1,500lbs less than GP7200.

The implied 6,000lbs savings in engine weight is conservative, as dry engine weight is ~60% of propulsion system weight.

Section 5: Performance analysis

Now let's finish estimating an OEW, L/D, and validating/estimating MTOW. So far the weight deltas I've estimated:

  • add ~41,000lbs for fuselage+contents
  • subtract ~13,000lbs for empennage
  • subtract ~6,000lbs for engines
  • so far the total delta is +22,000lbs

Now back to the wing:we need to estimate a weight delta from our bigger wing bending moment due to (1) heavier fuse+contents, (2) longer effective span, (3) ligher engines.

Before that, one more diversion: Payload reduction. The A388 has a payload of ~210,000lbs, depending on operator OEW. That seems excessive. If we reduce payload to 180,000lbs, we can still fit 800pax@225lbs. Or 700 pax and 20,000lbs of cargo. Max payload reduction reduces the MZFW wing bending moment, fuselage weight as well.

So in the past I've done spreadsheet modelling of these questions. The only reactions I've had to those efforts are hostility and silence. If we want to dig deeper into the issue (I do), then we should. For now, here's my guess: 15,000lbs of wing reinforcement.

On the A388, span-dependent wing weight is probably ~80,000lbs (~40% of wing weight, which is ~33% of OEW). I've escalated effective span by 8%, but a winglet's span extension doesn't imply the exponential weight implication of longer wings (drawback is added wetted area and winglet weight versus a higher-AR wing of the same area). So a 15,000lb delta is ~19% delta to span-dependent wing weight.

19% is a lot. And we haven't considered the effect of lower fuel storage in the wing at MTOW plus lighter engines, which has a secondary impact of decreasing the downward deflection of wings in the +2g "taxi bump" case.

Ok so that's my weight delta estimate. From a baseline A388 OEW of 616,000lbs, our A389NEO OEW is 653,000lbs.

What's our L/D? I'm gonna take a shortcut here and go by a (slightly) adjusted ratio of "Wetted Aspect Ratio" (WAR) = Span^2 / Swet
  • Effective span delta is 290 / 267 = 8.61%
  • A380 Swet estimated at 3,960m2
  • A389NEO Swet delta = 233.4 [fuselage stretch] - 215.4 [empennage shrink] + 40 [winglets] = 58m2
  • BUT, fuselage fineness increase means Fuselage Cdp decreases by 2%. Effective fuselage Swet delta is ~197m2
  • For WAR calculation purposes, A389NEO Swet is 3,980m2
  • L/D ratio is proportional to SQRT (WARA389NEO / WARA388)
  • A389NEO has 8.3% higher L/D, per model

Now the money question: what's the relative fuel burn and range? For that let's use the basic Breguet range equation and compare a 489-seat A388 (OEW = 616,000lbs) to a 601-seat (+23%) A389NEO (OEW=653,000lbs), with both planes flying to the A388's max pax-only range.

Breguet equation:
Range = L/D * Speed * ln (MTOW / MLanding))/SFC

Speed is the same, we know our modeled L/D, SFC, and MLanding (=OEW+pax) for each plane. So if we assume equal max range we can solve for the necessary MTOW and mission fuel burn.

Solving the equations, we get the A380-900NEO's MTOW at 1,200,000lbs. (again - I'm presenting the outcome of iterations, all the foregoing modeled parameters are interdependent.)

The A389NEO burns 23.3% less fuel for the trip, which means 37.6% lower fuel/pax (!!!!!).
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If these numbers are in the ballpark, we can probably all see that an A380-900NEO could be an attractive plane, assuming that Airbus uses aggressive winglets and trims the empennage. In fact, the (parasitic) drag savings from empennage reduction can more than compensate for the added fuselage drag on (IMJ) reasonable assumptions about the new empennage.

I'm going to post my thoughts about operating economics and market size later - both because of fatigue and in case anyone wants to point out some conceptual or arithmetic error before I move on.

In general, I think the A380-900NEO could be a good airliner By that I mean it would offer a capacity/efficiency tradeoff that is at least on trend with the broader landscape. Maybe its efficiency motivates some airlines to move out of their frequency comfort zone. As many members here know, I don't think that's the case with A388 (and wouldn't have been with ~2020 NEO). It's entirely possible that Airbus could build this plane and sell 30 or maybe 45 per year some day. And now I hope it happens. It's the only real shot we have at seeing a great VLA offering compelling economics and broadly expanding travel as have the great travel innovations of the past. Time to cheer for the A380.
 
LH707330
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Re: 2025ish A380-900NEO

Mon Jan 22, 2018 7:20 pm

Was that you or someone else that came up with the delta CASM / delta RASM metric when comparing different frames? Assuming your numbers are all correct, 37% might be compelling, but I'd also be interest in an estimate of the overall trip costs. My inner risk manager is asking "Why would I want to pay for this if all I fill it with is an extra 100 backpackers who don't make me any profit?"
 
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Matt6461
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Re: 2025ish A380-900NEO

Mon Jan 22, 2018 8:32 pm

LH707330 wrote:
Was that you or someone else that came up with the delta CASM / delta RASM metric when comparing different frames? Assuming your numbers are all correct, 37% might be compelling, but I'd also be interest in an estimate of the overall trip costs. My inner risk manager is asking "Why would I want to pay for this if all I fill it with is an extra 100 backpackers who don't make me any profit?"


You might be thinking of my "marginal capacity cost" metric, MCC= delta trip cost / delta capacity.
I've often discussed the yield/RASM curve versus the cost/CASM curve in connection with MCC, making the point that MCC must be lower than marginal RASM for a given capacity escalation. I once labeled this minimum marginal RASM (=>MCC) as "MBEY" for Marginal Break-Even Yield. MBEY is pretty clunky though. Would love a better label.

Re your risk manager's question:
I haven't completed writing up the economic analysis of this idea, but in broad strokes we're looking at 5% lower DOC trip cost versus A380 (assuming $2 gas and a 25% increase in sales price). That implies ~40% higher trip cost than a 777-9 with 90% higher capacity (MCC = .44).

To put some hard numbers on it:
  • 6000nm trip cost for A388 @$2 gas is ~$220k (Per Leeham with my own slight adjustment*)
  • A389NEO trip cost would be $210k, 777-9 trip cost $150k.
  • If we devote all of the A389NEO's 90% extra capacity to backpackers, that's about 500 Y-seats.
  • To cover operating cost delta 777-9 ---> A389NEO, we'd need $120k roundtrip, or $240/seat.
*Leeham uses 10.2% of aircraft value as the annual lease rate; airlines with good credit see more like 8%. Leeham uses 12hr daily utilization rate; 13-14 seems better - especially for a plane with great cash operating costs and relatively higher capital cost. You'll be able to keep that thing flying more than a cheaper, thirstier plane.

6000nm covers many northern TPAC flights. A quick price check online tells me the cheapest direct TPAC flights are in the $580 range, with $80 for fees and ~$500 for fares.
These are the kinds of "backpacker" fares that U.S. airlines bemoan and with which Chinese airlines are flooding the market. https://centreforaviation.com/insights/ ... est-369542

A plane like A380-900NEO would make these kinds of fares immensely profitable (whereas Chinese airlines need subsidies to offer them for now).
You can tell your risk manager that you'll be printing cash where others bleed, and will cover costs even if fares drop by half.
And in the meantime our baseline airliner for the marginal comparison - 777-9 - is pretty darn efficient itself and the costs apportioned to flying your premium and higher-yield Y pax are squarely in the profit zone.
Also tell the risk manager that no airline can compete for your (now-profitable) backpackers unless it too flies the A389NEO. So, yes, a new equilibrium will emerge with fares less than $580 but more than $240, but the bigger risk is that your competitor has the A389NEO and you don't: Even if your (above-backpacker) low-yield pax aren't your favorite, you can't afford to lose them all to competitors, and you can't afford to compete for them unless you have the A389NEO.

This logic works in other markets as well: On TATL, for example, longhaul LCC's are targeting backpackers but inevitably draw away much above-backpacker market share from legacies. A389NEO would allow BA, for example, to beat/match Norwegian's TATL fares while flying from LHR/JFK instead of STN/SWF/ISP. That both saves BA's market share and opens up a new, profitable market.

Of course the actual strategy will be some mid-point between boarding 500 additional backpackers and using your efficiency to offer greater space/amenities to comfort-sensitive passengers. An airline flying A389NEO could, for example, offer 20in wide, 36in pitch seats in its full-service Y class for the same price as airlines flying 17/18in*31/32 in 787/A350/777X. Similarly, premium seats could offer ~50% greater area/pax while maintaining CASM parity with smaller twins. Think EK's A380 F seats as your standard J product.
 
GalaxyFlyer
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Re: 2025ish A380-900NEO

Mon Jan 22, 2018 10:33 pm

Oh no, please not another useless A380 thread! What is it about the 380 (and 757) that generates such repetitive interest?

GF
 
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Slug71
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 6:02 am

Interesting analysis. I just think that if Airbus does a stretch, it will be a moderate stretch as was mulled by Airbus in 2015. IIRC, it was said to be around 50 extra seats. All indication from Airbus seems that anything larger, is unlikely. I think whatever they decide, it will be highly optimized as if it were a base model. I suspect it will by highly improved to satisfy EK's "massive update" needs.

"Plus" cabin will be an option for an additional 50-80 seats. Definitely think the Ultrafan will be an engine option. New wing and smaller VSTAB.

I think cost and weight reduction will be big key points of focus. Sourcing what it can from the A350 production line could help with costs. I think there's a good possibility that the MTOW goes down too.
 
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Matt6461
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 6:53 pm

Slug71 wrote:
Interesting analysis. I just think that if Airbus does a stretch, it will be a moderate stretch as was mulled by Airbus in 2015. IIRC, it was said to be around 50 extra seats. All indication from Airbus seems that anything larger, is unlikely. I think whatever they decide, it will be highly optimized as if it were a base model. I suspect it will by highly improved to satisfy EK's "massive update" needs.

"Plus" cabin will be an option for an additional 50-80 seats. Definitely think the Ultrafan will be an engine option. New wing and smaller VSTAB.

I think cost and weight reduction will be big key points of focus. Sourcing what it can from the A350 production line could help with costs. I think there's a good possibility that the MTOW goes down too.


Thanks.
I agree that Airbus would prefer not to do a full stretch if it doesn't have to. The bigger the plane is, the smaller its market niche.
A full stretch is probably necessary, however, to achieve the kind of economics the A380 needs (absent a new wing) to be successful.
Even a full stretch will be carrying "extra" wing and MLG weight/drag due to the initial strategic errors of this program. If you're not going to rebuild the wing/MLG, the marginal cost of extra capacity on an A380NEO platform is very low. So you might as well use it.
This dynamic existed for a NEO with much less efficient engines than Ultrafan will be. That's why Airbus was proposing a "half-stretch" that even EK view as unnecessary. But what's sufficient for EK wasn't for other airlines, which surely wanted to see better economics, which motivated the stretch proposal. Airbus couldn't get there with GEnx/Advance/TXWB engines, but it seems able to get there with Ultrafan engines.

Re cost and weight reduction - sure Airbus will go for that. Maybe Al-Li is possible? That could show a big impact on wing and (to a lesser extent) fuselage weight. Maybe trading out GLARE for Al-Li saves significant production expense as well. The obstacle, IMO, is that Boeing couldn't make Al-Li pencil out for the 777X. Most observers expected it as "low-hanging fruit."

I'm not as confident in the market appeal of this sketch as I am about the market appeal of a rewing or clean-sheet design. (Though I'm even less confident of the OEM appeal of a rewing or clean sheet.) A new wing would both decrease OEW and increase L/D. You'd have to - and want to - revise the MLG and belly fairing with a new wing. That'd be expensive (discussed a lot elsewhere) but would give exponential benefits over even my ambitious NEO sketch.

My guess, for now, is that Airbus has a good shot of making a 2025ish -900NEO work, and that will be "good enough" for a company seemingly content with just keeping the program going.
 
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Slug71
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 9:58 pm

Matt6461 wrote:
Slug71 wrote:
Interesting analysis. I just think that if Airbus does a stretch, it will be a moderate stretch as was mulled by Airbus in 2015. IIRC, it was said to be around 50 extra seats. All indication from Airbus seems that anything larger, is unlikely. I think whatever they decide, it will be highly optimized as if it were a base model. I suspect it will by highly improved to satisfy EK's "massive update" needs.

"Plus" cabin will be an option for an additional 50-80 seats. Definitely think the Ultrafan will be an engine option. New wing and smaller VSTAB.

I think cost and weight reduction will be big key points of focus. Sourcing what it can from the A350 production line could help with costs. I think there's a good possibility that the MTOW goes down too.


Thanks.
I agree that Airbus would prefer not to do a full stretch if it doesn't have to. The bigger the plane is, the smaller its market niche.
A full stretch is probably necessary, however, to achieve the kind of economics the A380 needs (absent a new wing) to be successful.
Even a full stretch will be carrying "extra" wing and MLG weight/drag due to the initial strategic errors of this program. If you're not going to rebuild the wing/MLG, the marginal cost of extra capacity on an A380NEO platform is very low. So you might as well use it.
This dynamic existed for a NEO with much less efficient engines than Ultrafan will be. That's why Airbus was proposing a "half-stretch" that even EK view as unnecessary. But what's sufficient for EK wasn't for other airlines, which surely wanted to see better economics, which motivated the stretch proposal. Airbus couldn't get there with GEnx/Advance/TXWB engines, but it seems able to get there with Ultrafan engines.


Agreed. I think it's highly probable a NEO will have a redesigned wing, especially because of the part I've highlighted. Even though it doesn't seem to be as inefficient as first thought, it's still over engineered. Even for a full stretch. IIRC, the new wing rib feet that was introduced to fix the cracking also added 1 or 2 tons of weight.

Matt6461 wrote:
Re cost and weight reduction - sure Airbus will go for that. Maybe Al-Li is possible? That could show a big impact on wing and (to a lesser extent) fuselage weight. Maybe trading out GLARE for Al-Li saves significant production expense as well. The obstacle, IMO, is that Boeing couldn't make Al-Li pencil out for the 777X. Most observers expected it as "low-hanging fruit."


Possibly, but I think CFRP will still have the edge for most of the components due to cost. I'd think the manufacturing and production processes for CFRP has been significantly improved since it's introduction and the costs are probably much lower today. Especially with 3D printing. There is also CNT which could be introduced for certain parts as it is said to be around 10 times stronger than CFRP at the same weight or a tenth of the weight with the same strength. Perhaps a combination of Al-Li and CNT in key loading areas?
I think Airbus will stick with GLARE for the fuselage though. CFRP doesn't seem to offer any clear weight/cost advantage and the overall design is still considered very efficient. Keeping that in mind, once you start going in that direction, a clean sheet make more sense i'd imagine. Even though i'd welcome a new nose. I think it would look so much sleeker with the cockpit raised slightly(still below the second deck) and curved cockpit windows. And maybe a pointier nose (like the A350's, not 747). But the window belts and door frames, can also be sourced from A350 production lines.

Matt6461 wrote:
I'm not as confident in the market appeal of this sketch as I am about the market appeal of a rewing or clean-sheet design. (Though I'm even less confident of the OEM appeal of a rewing or clean sheet.) A new wing would both decrease OEW and increase L/D. You'd have to - and want to - revise the MLG and belly fairing with a new wing. That'd be expensive (discussed a lot elsewhere) but would give exponential benefits over even my ambitious NEO sketch.

My guess, for now, is that Airbus has a good shot of making a 2025ish -900NEO work, and that will be "good enough" for a company seemingly content with just keeping the program going.


The MLG might not be that expensive though. Again, I look at the A350. If the A359's gear is good for 280t, couldn't you combine a set good for around 560t? Anyone know the weight difference between the A380's 4-wheel bogie vs the A359's? Still, you can replace the two A380's 6-wheel bogies with the A359's. How complex would it be to reduce the current A380 by 15t? What are the penalties? If a stretch is done, would the A359's gear still work?
 
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 10:14 pm

One showstopper is that RR isn't pointing the Ultrafan at this market segment at the moment. They are positioning the engine for the next wave of single aisle aircraft, <35Klbs.

Whether there is a compelling case to go to an A380 installation is by no means clear as it would definitely need a second or third use for the engine to cover development costs. Advance looks more possible as RR did at one stage say they could be offering a crash program to develop an Advance by 2020 or thereabouts for the A380 as much of the cost so far was either sunk or able to be spread across other projects.

What would work well and also reduce Airbus' costs is a plug-compatible Advance to go on a T900 pylon and systems setup. Might this be an option for a minimum-change A380NEO if more advanced changes are uneconomical? Or will RR have had enough of a certain customer?
 
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 10:58 pm

Slug71 wrote:
I think it's highly probable a NEO will have a redesigned wing,

Slug71 wrote:
I think CFRP will still have the edge for most of the components due to cost.


You're talking about a lot of revisions that I don't see falling under the rubric of "NEO." It's maybe just a semantic dispute but a new wing and switch to CFRP materials for fuselage/wing would be something approaching clean sheet redesign.

Don't get me wrong - I love talking new wing for the A380. I just don't see it being very likely. If it were at all likely, the time to do it may have passed. By the time time a new wing EIS's now, it'll cost so much that it would probably be better to start over with a CFRP fuselage that would be lighter have a more efficient layout. I have separate thread for that, though. viewtopic.php?t=776333

Slug71 wrote:
Even though it doesn't seem to be as inefficient as first thought, it's still over engineered


To be clear, I'm not changing my opinion on the wing's efficiency. It's very inefficient, but there was no way to build an efficient 80m wing for a 650-seater using 2000 technology. Nothing wrong with the engineering, just a bad top-level strategic decision to build a 650-seater at all.

Slug71 wrote:
If a stretch is done, would the A359's gear still work?


You can't just move gear from one plane to another. Would be cheaper to start from scratch. Aside from the bogies/trucks, everything about the gear relates to the fuselage/wing it supports.
 
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 11:20 pm

Channex757 wrote:
RR isn't pointing the Ultrafan at this market segment at the moment. They are positioning the engine for the next wave of single aisle aircraft, <35Klbs.


Not true. Good for up to 100k lb-T. http://aviationweek.com/technology/roll ... -test-gear
 
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Re: 2025ish A380-900NEO

Tue Jan 23, 2018 11:31 pm

Matt6461 wrote:
Channex757 wrote:
RR isn't pointing the Ultrafan at this market segment at the moment. They are positioning the engine for the next wave of single aisle aircraft, <35Klbs.


Not true. Good for up to 100k lb-T. http://aviationweek.com/technology/roll ... -test-gear

Read my point again and come back.

RR is positioning the engine for the biggest potential market. The tech might be capable, but RR wants to build for volume. That was what John Leahy was on about, RR is aiming for Ultrafan to be on the 737 and A320 replacements.
 
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Re: 2025ish A380-900NEO

Wed Jan 24, 2018 7:16 am

Matt6461 wrote:
Re cost and weight reduction - sure Airbus will go for that. Maybe Al-Li is possible? That could show a big impact on wing and (to a lesser extent) fuselage weight. Maybe trading out GLARE for Al-Li saves significant production expense as well. The obstacle, IMO, is that Boeing couldn't make Al-Li pencil out for the 777X. Most observers expected it as "low-hanging fruit."


Actually there have been recent automation improvements/cost reductions in the GLARE/FML production process, and Airbus is bullish enough about GLARE to target a fifty-fold production rise. I'd guess it's just as likely that GLARE usage would increase in a new 380 derivative.

Day One highlights from 2016 CFK Valley Stade Conference (7/31/2016 - see bottom section)
The resurgence of GLARE (8/18/2016)
Fiber-metal laminates in the spotlight (7/12/2017)
 
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Re: 2025ish A380-900NEO

Wed Jan 24, 2018 11:42 am

Slug71 wrote:
. IIRC, the new wing rib feet that was introduced to fix the cracking also added 1 or 2 tons of weight.

Any reliable source for that?

IMU the hybrid design ( CFRP web and alloy feet ) saved 300kg overall <selected>.
Airbus returned to all alloy items.
The alloy used was changed.

If you leave out the wheelbarrows of money needed for fixing
the overall effect should be near weight neutral.
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Re: 2025ish A380-900NEO

Wed Jan 24, 2018 3:26 pm

WIederling wrote:
Slug71 wrote:
. IIRC, the new wing rib feet that was introduced to fix the cracking also added 1 or 2 tons of weight.

Any reliable source for that?

IMU the hybrid design ( CFRP web and alloy feet ) saved 300kg overall <selected>.
Airbus returned to all alloy items.
The alloy used was changed.

If you leave out the wheelbarrows of money needed for fixing
the overall effect should be near weight neutral.


I can poke around, but I'm just going off what I read at the time. Of course, a lot of it could have been misinformation.


Edit; Can't find much on it now, so it was probably not accurate. Seems it may just be a 90kg increase.

https://www.flightglobal.com/news/artic ... ue-372288/
 
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Re: 2025ish A380-900NEO

Wed Jan 24, 2018 5:14 pm

Matt6461 wrote:
Slug71 wrote:
I think it's highly probable a NEO will have a redesigned wing,

Slug71 wrote:
I think CFRP will still have the edge for most of the components due to cost.


You're talking about a lot of revisions that I don't see falling under the rubric of "NEO." It's maybe just a semantic dispute but a new wing and switch to CFRP materials for fuselage/wing would be something approaching clean sheet redesign.

Don't get me wrong - I love talking new wing for the A380. I just don't see it being very likely. If it were at all likely, the time to do it may have passed. By the time time a new wing EIS's now, it'll cost so much that it would probably be better to start over with a CFRP fuselage that would be lighter have a more efficient layout. I have separate thread for that, though. viewtopic.php?t=776333


Think there might have been a little misunderstanding as I said the same thing about a clean sheet. lol
I don't expect a change from GLARE for the fuselage. I doubt there will be any change to the fuselage other than weight and cost improvements. If and where possible. One possible change to the fuselage might be, using the CFRP door frames and window belts sourced from the A350 production line as a cost reduction measure.
I raised the issue of weight between GLARE and CFRP (for the fuselage) before and the consensus was, that there is no real weight advantage of GLARE over CFRP.

I do think it'll have an all new CFRP wing though. Theres no good reason(other than cost) not to change it. It's not efficient/optimal now, not with a small stretch, and unlikely even with a full -900 stretch(as the freighter is dead). If EK wants a "massive update", the only place it can really come from, is the wing.

Matt6461 wrote:
Slug71 wrote:
If a stretch is done, would the A359's gear still work?


You can't just move gear from one plane to another. Would be cheaper to start from scratch. Aside from the bogies/trucks, everything about the gear relates to the fuselage/wing it supports.


That's interesting. And surprising that it would be cheaper to start from scratch. With the A350's gear in production and about a decade ahead(thinking materials) of the A380's gear, I would have though it would be cheaper to work off that and focus the design changes to the gear bay. I'm specifically referring to the bogies/trucks here. But it's obviously not as simple as that.
 
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Re: 2025ish A380-900NEO

Thu Jan 25, 2018 12:00 am

Slug71 wrote:
Think there might have been a little misunderstanding as I said the same thing about a clean sheet. lol


My bad. But I'd say that what you're proposing - what I myself have proposed repeatedly in the past - would rapidly approach the cost/risk of a clean-sheet project. New wing, empennage, MLG, engines, revisions to the fuselage... The A380's fuselage, while excellent compared to all other existing planes - is somewhat suboptimal. Especially if you keep the current capacity when rewinging (As I think you should). At some point, the marginal benefit of starting from scratch exceeds the savings from reusing the fuselage. Given the benefits of CFRP at A380 scale, later next decade is probably past that point.

Slug71 wrote:
If EK wants a "massive update", the only place it can really come from, is the wing.


What I've sketched above could be construed as "massive update." New engines, empennage, stretch, large winglets...
That said I hope you're right.

CowAnon wrote:
Actually there have been recent automation improvements/cost reductions in the GLARE/FML production process


Thanks!
Interesting stuff but it makes me wonder: why specify that FML is good for fuselage and wing bottoms - presumably only those.
It raises a theory - is GLARE incapable of sustaining the highest compressive forces? Maybe due to delamination at these levels, absent prohibitive thickness? Wing bottoms and upper fuselage panels (i.e. A380 use of GLARE) experience significant tensile stress but comparatively little compressive stress.

If that's the correct explanation of GLARE/FML's suggested and actual usage, then GLARE doesn't seem more than a partial structural material. And if that's true, then I can't see mixed GLARE/CFRP application - even if GLARE is a little lighter than CFRP that adds a lot of complexity.

Still, it would be interesting for Airbus to use GLARE along the A380's wing bottom and maybe over more of the upper fuselage. Back of napkin suggests that's maybe ~100,00lbs of aluminum on the A380; 30% savings would be enormous and so would half of that.
 
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Re: 2025ish A380-900NEO

Thu Jan 25, 2018 5:07 pm

Matt6461 wrote:
Slug71 wrote:
Think there might have been a little misunderstanding as I said the same thing about a clean sheet. lol


My bad. But I'd say that what you're proposing - what I myself have proposed repeatedly in the past - would rapidly approach the cost/risk of a clean-sheet project. New wing, empennage, MLG, engines, revisions to the fuselage... The A380's fuselage, while excellent compared to all other existing planes - is somewhat suboptimal. Especially if you keep the current capacity when rewinging (As I think you should). At some point, the marginal benefit of starting from scratch exceeds the savings from reusing the fuselage. Given the benefits of CFRP at A380 scale, later next decade is probably past that point.


It's all good. Probably some misunderstanding from my side as well. But you are correct. It could easily blur the lines between a update and a clean sheet. It's really too bad the -800 wasn't chosen as the base model. I think that's what adds greatly to the complexity of an update.

Matt6461 wrote:
Slug71 wrote:
If EK wants a "massive update", the only place it can really come from, is the wing.


What I've sketched above could be construed as "massive update." New engines, empennage, stretch, large winglets...
That said I hope you're right.


True.

Matt6461 wrote:
CowAnon wrote:
Actually there have been recent automation improvements/cost reductions in the GLARE/FML production process


Thanks!
Interesting stuff but it makes me wonder: why specify that FML is good for fuselage and wing bottoms - presumably only those.
It raises a theory - is GLARE incapable of sustaining the highest compressive forces? Maybe due to delamination at these levels, absent prohibitive thickness? Wing bottoms and upper fuselage panels (i.e. A380 use of GLARE) experience significant tensile stress but comparatively little compressive stress.

If that's the correct explanation of GLARE/FML's suggested and actual usage, then GLARE doesn't seem more than a partial structural material. And if that's true, then I can't see mixed GLARE/CFRP application - even if GLARE is a little lighter than CFRP that adds a lot of complexity.

Still, it would be interesting for Airbus to use GLARE along the A380's wing bottom and maybe over more of the upper fuselage. Back of napkin suggests that's maybe ~100,00lbs of aluminum on the A380; 30% savings would be enormous and so would half of that.


Thats very interesting! Thanks for sharing CowAnon.

@Matt6461, To be be fair it does say it is BEST SUITED for those areas.
"Mourik says FML is best suited for fuselages, bottom wing skins and, as described above, leading edges of wing and horizontal or vertical stabilizers."

However I do myself wonder why? Perhaps due to cost/complexity at the time and that is now changing? After reading all of that though, it definitely seems like FMLs (CFMLs specifically) is the way forward. Due to minimum thickness requirements of CFRP, wouldn't FMLs still have an advantage on larger twins or VLAs? Or does the advantage start swinging in the way of CFRP once you start increasing the thickness of FMLs for larger aircraft? FMLs seems to have a weight, fatigue, size of panels, and cost benefit over CFRP. Or at least the cost part is coming.

One of the articles also mentioned Al-Li. It almost seems like the perfect FML would be using Al-Li and CNT. After a little digging though, It seems Al-Li is not quite there yet. It's still very expensive and has poor corrosion resistance and fatigue strength. But getting better.

Looking at this though,

Image

There's A LOT of blue that could get turned yellow! Especially if it's cheaper and lighter.
Last edited by Slug71 on Thu Jan 25, 2018 5:27 pm, edited 1 time in total.
 
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Re: 2025ish A380-900NEO

Thu Jan 25, 2018 5:24 pm

I glanced back over those links CowAnon provided and at the bottom of one of them was this,

Out of Autoclave FML
Citing FML's benefits in aircraft construction, NASA Langley sought to address GLARE's traditional manufacturing issues of size limitations and expensive, labor-intensive autoclave processing by developing a vacuum assisted resin transfer molding (VARTM) method (see "Fiber Metal Laminates Made by the VARTM Process"). So far, Airbus and its Tier 1s appear to be focusing on smart robotic-based automation as the manufacturing solution vs. eliminating the autoclave.


So I'm guessing the use for the bottom wing skins, fuselages etc, is due to cost of the current manufacturing process.
From the VARTM link,

Current commercially available FMLs can be expensive to produce, and part size is limited due to the required prepreg and use of an autoclave or press in consolidation.
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 1:22 am

Slug7 wrote:
So I'm guessing the use for the bottom wing skins, fuselages etc, is due to cost of the current manufacturing process.


I can't think of any reason why part size or manufacturing method would result in properties amenable to high-tensile, but not high-compressive sections. A wing bottom is no longer than a wing top, just thinner. Same for fuse bottom versus top.

Slug71 wrote:
Due to minimum thickness requirements of CFRP, wouldn't FMLs still have an advantage on larger twins or VLAs?


I would think exactly the opposite dynamic would hold, as your next sentence suggests. That said, having reason to guess the trendline doesn't give you the answer to the question of which is lighter at a given thickness.

Anybody else know why GLARE seems not-suggested for high-compression uses, and/or when each material has a strength/weight advantage?
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 1:50 am

This is pure speculation but maybe it is down to the sandwich type material tat makes up GLARE being better in tension than compression. Stretching and flexing the glass fibre component may be more tolerated than compressing them, in which case the thin glass strands in the sandwich might start breaking down.

I'm only using a thought experiment here, going off usage of fibreglass in various projects and repairs in the past. Crush the stuff and it starts becoming powdery as the strands snap under squeezing loads. Stretch them as in a fuselage section inflating under pressure and they happily handle the loading.
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 2:28 am

I searched around and found a review of the various FMLs that have been researched. Evidently there are FML types that perform well in compression (aluminum+M5 fiber or magnesium-fiberglass), but it depends on the particular material combinations. (I'm guessing the compression-friendly FMLs are far from production-ready, too.) Also, carbon fiber doesn't work well with Al because it causes galvanic corrosion in the aluminum, plus incompatibilities with stiffness values and thermal expansion coefficients.

http://www.springer.com/cda/content/doc ... 261-c2.pdf
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 4:03 am

Channex757 wrote:
This is pure speculation but maybe it is down to the sandwich type material tat makes up GLARE being better in tension than compression. Stretching and flexing the glass fibre component may be more tolerated than compressing them, in which case the thin glass strands in the sandwich might start breaking down.

I'm only using a thought experiment here, going off usage of fibreglass in various projects and repairs in the past. Crush the stuff and it starts becoming powdery as the strands snap under squeezing loads. Stretch them as in a fuselage section inflating under pressure and they happily handle the loading.


Very good point and definitely plausible.

CowAnon wrote:
I searched around and found a review of the various FMLs that have been researched. Evidently there are FML types that perform well in compression (aluminum+M5 fiber or magnesium-fiberglass), but it depends on the particular material combinations. (I'm guessing the compression-friendly FMLs are far from production-ready, too.) Also, carbon fiber doesn't work well with Al because it causes galvanic corrosion in the aluminum, plus incompatibilities with stiffness values and thermal expansion coefficients.

http://www.springer.com/cda/content/doc ... 261-c2.pdf


Interesting. I wonder if this is maybe something that CNT could resolve? I know it's still carbon, but very different process.
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 5:06 pm

Slug71 wrote:
There's A LOT of blue that could get turned yellow! Especially if it's cheaper and lighter.


IMU GLARE is not suitable for complex forms. i.e. 2D yes 3D no. ??
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 5:14 pm

Slug71 wrote:
Interesting. I wonder if this is maybe something that CNT could resolve? I know it's still carbon, but very different process.


CNT in Metal Matrix Composites:
https://www.sciencedirect.com/science/a ... 8816338312

wonder where that goes.
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 6:03 pm

Slug71 wrote:
Matt6461 wrote:
Slug71 wrote:
Interesting analysis. I just think that if Airbus does a stretch, it will be a moderate stretch as was mulled by Airbus in 2015. IIRC, it was said to be around 50 extra seats. All indication from Airbus seems that anything larger, is unlikely. I think whatever they decide, it will be highly optimized as if it were a base model. I suspect it will by highly improved to satisfy EK's "massive update" needs.

"Plus" cabin will be an option for an additional 50-80 seats. Definitely think the Ultrafan will be an engine option. New wing and smaller VSTAB.

I think cost and weight reduction will be big key points of focus. Sourcing what it can from the A350 production line could help with costs. I think there's a good possibility that the MTOW goes down too.


Thanks.
I agree that Airbus would prefer not to do a full stretch if it doesn't have to. The bigger the plane is, the smaller its market niche.
A full stretch is probably necessary, however, to achieve the kind of economics the A380 needs (absent a new wing) to be successful.
Even a full stretch will be carrying "extra" wing and MLG weight/drag due to the initial strategic errors of this program. If you're not going to rebuild the wing/MLG, the marginal cost of extra capacity on an A380NEO platform is very low. So you might as well use it.
This dynamic existed for a NEO with much less efficient engines than Ultrafan will be. That's why Airbus was proposing a "half-stretch" that even EK view as unnecessary. But what's sufficient for EK wasn't for other airlines, which surely wanted to see better economics, which motivated the stretch proposal. Airbus couldn't get there with GEnx/Advance/TXWB engines, but it seems able to get there with Ultrafan engines.


Agreed. I think it's highly probable a NEO will have a redesigned wing, especially because of the part I've highlighted. Even though it doesn't seem to be as inefficient as first thought, it's still over engineered. Even for a full stretch. IIRC, the new wing rib feet that was introduced to fix the cracking also added 1 or 2 tons of weight.

Matt6461 wrote:
Re cost and weight reduction - sure Airbus will go for that. Maybe Al-Li is possible? That could show a big impact on wing and (to a lesser extent) fuselage weight. Maybe trading out GLARE for Al-Li saves significant production expense as well. The obstacle, IMO, is that Boeing couldn't make Al-Li pencil out for the 777X. Most observers expected it as "low-hanging fruit."


Possibly, but I think CFRP will still have the edge for most of the components due to cost. I'd think the manufacturing and production processes for CFRP has been significantly improved since it's introduction and the costs are probably much lower today. Especially with 3D printing. There is also CNT which could be introduced for certain parts as it is said to be around 10 times stronger than CFRP at the same weight or a tenth of the weight with the same strength. Perhaps a combination of Al-Li and CNT in key loading areas?
I think Airbus will stick with GLARE for the fuselage though. CFRP doesn't seem to offer any clear weight/cost advantage and the overall design is still considered very efficient. Keeping that in mind, once you start going in that direction, a clean sheet make more sense i'd imagine. Even though i'd welcome a new nose. I think it would look so much sleeker with the cockpit raised slightly(still below the second deck) and curved cockpit windows. And maybe a pointier nose (like the A350's, not 747). But the window belts and door frames, can also be sourced from A350 production lines.

Matt6461 wrote:
I'm not as confident in the market appeal of this sketch as I am about the market appeal of a rewing or clean-sheet design. (Though I'm even less confident of the OEM appeal of a rewing or clean sheet.) A new wing would both decrease OEW and increase L/D. You'd have to - and want to - revise the MLG and belly fairing with a new wing. That'd be expensive (discussed a lot elsewhere) but would give exponential benefits over even my ambitious NEO sketch.

My guess, for now, is that Airbus has a good shot of making a 2025ish -900NEO work, and that will be "good enough" for a company seemingly content with just keeping the program going.


The MLG might not be that expensive though. Again, I look at the A350. If the A359's gear is good for 280t, couldn't you combine a set good for around 560t? Anyone know the weight difference between the A380's 4-wheel bogie vs the A359's? Still, you can replace the two A380's 6-wheel bogies with the A359's. How complex would it be to reduce the current A380 by 15t? What are the penalties? If a stretch is done, would the A359's gear still work?

I agree a new wing and new gear. The wing must be lighter.

Ultrafan or GTF. But the engine is the longest lead time item. 2025 has already been missed. It takes that long to engineer and certify an engine that proceeds the 15 month long airframe flight testing program.

I believe CFRP wing, folding wingtps, new geared engine, and a minimum 83m length are required. I see a large market.

I believe the A388 didn't do well as the quantity of new seats that were free vs. had to be filled was too high. My predicted minimum length is versus the 779 post PIPs. Half the added seats vs. the 779 must be carried free or the A380 stretch won't pay for its engineering and production costs.

For the timeframe of service, Boeing will counter with the 787 MAX too.

I think an A389NEO has great potential. But it must be a Udvar-Hazy length with a wingspan greater than 80m, that folds into 80m span, lightened (CFRP or GFRP) wing, and engines better than the amazing GE9X.

I say amazing as I see every reason it will be promise a la GE90-115. Yes, I believe there was management reserve in promised fuel burn.

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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 8:05 pm

Say at 505T MTOW the six-wheel bogey could be replaced by an 4-wheel one and could be stored vertically. Say this would save 1.2 container length. Now say they could get the weight down to 490T by:

    much smaller 80m CFRP wing
    fuel load reduction from GTF engine, lower MTOW, massive induced drag reduction
    smaller MLG
    smaller empenage
    slightly lighter engines (yes bypass goes up but thrust requirement goes down drastically, from MTOW/induced drag).
    Slight range reduction (can later be restored through PIP's)
    Etc.


Now say they use those 15T (505-490T) to stretch the plane 1.8 container length (+2.7m).

So now you looking at a 75.5m, 505T A380-850, that will fit into the 80m box with no problem, folding wings or induced drag penalty with:

    +50 seats
    44 LD3 containers (+6 or +16%). Meaning much more commercial payload to volume ratio
    extremely efficient engines
    extremely efficient fuselage (floor area/wetted area)
    Much improved weight per seat
    competitive induced drag levels (unlike CEO) due to weight reduction, AR increase to 9.5 also due to improved/enlarged winglets
    reduced landing fees


If technically feasible I think this will be the preferred option. A full fledged A380-900 especially when making full use of the plus seating improvements will just have too much capacity. It will again be the whole “how will we get this thing filled profitably” fear and then some.

Engines are perfect to be shared with a reduced range A330 successor. That will sufficiently de-risk and reduce cost on that side of the program.
Last edited by Taxi645 on Fri Jan 26, 2018 8:32 pm, edited 5 times in total.
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 8:14 pm

Lightsaber wrote:
Half the added seats vs. the 779 must be carried free or the A380 stretch won't pay for its engineering and production costs.


Agree re the economic target. I don't know how much of the OP you read (it's a little long I realize), but I project beating that target: 44% marginal capacity cost (MCC), meaning 56% of added seats are free. Because this is a very loose projection, and due to 777-9 PIP's, let's call it 50% MCC.

The economic target is based on couple aero/structural assumptions on which I'd appreciate your opinion/input:
  • That Airbus can achieve ~290ft efffective span via ~21ft winglets. That's a proportionately bigger span delta than I've ever seen from winglets...
  • That Airbus can reduce empennage Swet by ~30% and weight by ~10,000lbs with longer lever arm, FBW enhancement, higher minimum control speed at landing.

Lightsaber wrote:
83m length


It seems reasonable that SUH length be permitted. I modeled 80m length but going to 83m would very efficient given wing area and MLG are already sized for it.

Lightsaber wrote:
I believe CFRP wing, folding wingtps, new geared engine, and a minimum 83m length are required.
A380 stretch won't pay for its engineering and production costs.


That's been my preferred position for years (minus the stretch), but I'm trying to make the best possible argument for a NEO on the same wing.
I agree that Airbus will have difficulty seeing a lot of profit even it can build 30 big NEO's/year.
But Airbus' ambitions for this program seem so small these days that it would love enhancements that merely pay for themselves.
Last edited by Matt6461 on Fri Jan 26, 2018 8:24 pm, edited 1 time in total.
 
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Re: 2025ish A380-900NEO

Fri Jan 26, 2018 8:23 pm

Taxi645 wrote:
Say at 505T MTOW the six-wheel bogey could be replaced by an 4-wheel one and could be stored vertically. Say this would save 1.2 container length.


To harvest the container length you need to completely redesign the MLG bay. I proposed this in past A380X sketches and it would be (operationally) beneficial. But requires extensive fuse rework. Combined with the new wing, MLG, empennage, engines, we're probably talking a $10b project.

That'd be worth it, IMO, for 2021 EIS. But for post-2025 EIS it retains a suboptimal, mostly metal fuselage designed for 1000-pax stretch. Probably better to spend 50% more and get an optimal 500-seat, plastic/CNTP/whatever fuselage and much broader market appeal.
 
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Re: 2025ish A380-900NEO

Sun Jan 28, 2018 9:57 am

Matt6461 wrote:
LH707330 wrote:
Was that you or someone else that came up with the delta CASM / delta RASM metric when comparing different frames? Assuming your numbers are all correct, 37% might be compelling, but I'd also be interest in an estimate of the overall trip costs. My inner risk manager is asking "Why would I want to pay for this if all I fill it with is an extra 100 backpackers who don't make me any profit?"


You might be thinking of my "marginal capacity cost" metric, MCC= delta trip cost / delta capacity.
I've often discussed the yield/RASM curve versus the cost/CASM curve in connection with MCC, making the point that MCC must be lower than marginal RASM for a given capacity escalation. I once labeled this minimum marginal RASM (=>MCC) as "MBEY" for Marginal Break-Even Yield. MBEY is pretty clunky though. Would love a better label.

Re your risk manager's question:
I haven't completed writing up the economic analysis of this idea, but in broad strokes we're looking at 5% lower DOC trip cost versus A380 (assuming $2 gas and a 25% increase in sales price). That implies ~40% higher trip cost than a 777-9 with 90% higher capacity (MCC = .44).


Fascinating analysis! Just a few thoughts

Maybe I am being skeptical here, but only ~370 seats for a 779 with this sort of F/J/W/Y ratio seems pessimistic (10% seats J, 1% seats F, ~15% W). If assuming more proportion of seats are Y on the superwhale, RASM also decreases vs the 779.

The projected ~40% trip cost increase vs 779 also seems optimistic, given how much operation costs don't have economies of scale. With your 90% extra capacity estimate, that already implies paying 12-14 extra flight attendants 6-8 hours each for a TPAC, not exactly trivial. Extra airport fees also appear to scale up linearly according to MTOW at these sorts of weights.. So I don't think the economic numbers would be as rosy as you imply...
 
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Re: 2025ish A380-900NEO

Sun Jan 28, 2018 1:46 pm

Matt6461 wrote:
Taxi645 wrote:
Say at 505T MTOW the six-wheel bogey could be replaced by an 4-wheel one and could be stored vertically. Say this would save 1.2 container length.


To harvest the container length you need to completely redesign the MLG bay. I proposed this in past A380X sketches and it would be (operationally) beneficial. But requires extensive fuse rework. Combined with the new wing, MLG, empennage, engines, we're probably talking a $10b project.

That'd be worth it, IMO, for 2021 EIS. But for post-2025 EIS it retains a suboptimal, mostly metal fuselage designed for 1000-pax stretch. Probably better to spend 50% more and get an optimal 500-seat, plastic/CNTP/whatever fuselage and much broader market appeal.


I think it is quite imaginable that the above optimization can easily sell more than 500 copies. That $10b then turns into a maximum $20m addition per frame. A considerable but not prohibitive amount.

An 80m A380-900 is a +120 seat proposition (over more than 200 seats in plus configuration). I know travel will grow, but I think it's just too much. It then would've been better to make a new design as you've argued. Since Airbus went for the deal with Emirates it seems they believe a successful 2nd generation A380 can be launched. I suspect they found a way to make the 850 work with GTF engines. I highly doubt it will be in the 900 form:

- Less niche market or yield "angst" compared to a 900
- Allows more frequencies than 900
- Unlike a 900 induced drag and wake problem of the CEO can be easily be solved within the 80m box.
- Still a huge 20% MTOW reduction per seat
- Engines can be shared with a more medium range A330 successor
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Re: 2025ish A380-900NEO

Sun Jan 28, 2018 6:22 pm

Taxi645 wrote:
Matt6461 wrote:
Taxi645 wrote:
Say at 505T MTOW the six-wheel bogey could be replaced by an 4-wheel one and could be stored vertically. Say this would save 1.2 container length.


To harvest the container length you need to completely redesign the MLG bay. I proposed this in past A380X sketches and it would be (operationally) beneficial. But requires extensive fuse rework. Combined with the new wing, MLG, empennage, engines, we're probably talking a $10b project.

That'd be worth it, IMO, for 2021 EIS. But for post-2025 EIS it retains a suboptimal, mostly metal fuselage designed for 1000-pax stretch. Probably better to spend 50% more and get an optimal 500-seat, plastic/CNTP/whatever fuselage and much broader market appeal.


I think it is quite imaginable that the above optimization can easily sell more than 500 copies. That $10b then turns into a maximum $20m addition per frame. A considerable but not prohibitive amount.

An 80m A380-900 is a +120 seat proposition (over more than 200 seats in plus configuration). I know travel will grow, but I think it's just too much. It then would've been better to make a new design as you've argued. Since Airbus went for the deal with Emirates it seems they believe a successful 2nd generation A380 can be launched. I suspect they found a way to make the 850 work with GTF engines. I highly doubt it will be in the 900 form:

- Less niche market or yield "angst" compared to a 900
- Allows more frequencies than 900
- Unlike a 900 induced drag and wake problem of the CEO can be easily be solved within the 80m box.
- Still a huge 20% MTOW reduction per seat
- Engines can be shared with a more medium range A330 successor


Both the projected sales and development costs seem rather optimistic IMO. The 777X involved far less new stuff (wing + engine) and its rumored to be a 6-7B program, it's hard to imagine a new MLG, wingbox, and empennage not costing at least 5B extra on top of that.

The A380 is ten years into EIS and only has 330 total orders, some of which are dubious in nature. 500 orders for an improved version, within a "reasonable" timeline (~10 years after announcement) seems... unlikely. Remember that the next biggest jet has only amassed 20 orders within the last 3.5 years, so it's not just an A380 problem. Even if there is some latent demand for VLAs not satisfied by the current planes. Given the timeline of such a potential A380mk2 for a post 2025 EIS, it'd be simple enough for Boeing to use their 777X PiPs, stretch the fuselage to 81/82m and again, get "close" in CASM with a smaller plane, which would leave Airbus in a bind again..
 
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 5:45 am

Taxi645 wrote:
I think it is quite imaginable that the above optimization can easily sell more than 500 copies. That $10b then turns into a maximum $20m addition per frame.


Sure, absent any similarly-efficient competition, an A380X/NWO could sell 1,000 copies, and do so at ~$40mn profit/frame (20mn@500 frames is far too low return for a long-horizon, risky investment. Simply returning cash invested would be a serious program failure for investors and Airbus alike.).

The problem is that a world in which an A380X/NWO sees great market success is a world in which rivals (Boeing but maybe CRAIC/COMAC also) have an opportunity to build a clean-sheet product that beats your A380X/NWO's unit costs at lower capacity level. That's a recipe for capturing the whole market.

This was a much better idea for 2021 EIS (match the 777X's tech investment but greatly exceed its performance delta). By 2026 you'll be competing against much better planes - 787MAX for instance, as well as whatever follows.

JustSomeDood wrote:
Given the timeline of such a potential A380mk2 for a post 2025 EIS, it'd be simple enough for Boeing to use their 777X PiPs, stretch the fuselage to 81/82m and again, get "close" in CASM with a smaller plane, which would leave Airbus in a bind again..


Have to disagree here. There's no way a 80m+ 777-10 comes close to a full-scale A380X/NWO with new CFRP wing. On that plane you're talking up to 50% fuel burn delta. A PIP'd 777-10 stretch would see maximum 3% lower SFC, ~4% better structural efficiency, but slightly lower L/D. Impossible to hit even double-digit fuel/pax reduction.

Re sales of an A380X/NWO compared to A380CEO - apples and oranges. Airlines care about the economic traits of a plane, not its family designation. There'd be more economic difference between a rewinged A380 and A388 than between A359 and A345.
 
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 8:00 am

Regarding the engines. The fan will be a lot bigger, as one would expect the bypass ration to reach around 15:1 on a second gen. GTF. So a very basic calculation would see around a 130-135 inch fan diameter.
 
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 9:37 am

JustSomeDood wrote:
Both the projected sales and development costs seem rather optimistic IMO. The 777X involved far less new stuff (wing + engine) and its rumored to be a 6-7B program, it's hard to imagine a new MLG, wingbox, and empennage not costing at least 5B extra on top of that.


As argued a 850 could share engines with a A330 successor, so yes I think it would be close to $10B.

JustSomeDood wrote:
The A380 is ten years into EIS and only has 330 total orders, some of which are dubious in nature. 500 orders for an improved version, within a "reasonable" timeline (~10 years after announcement) seems... unlikely. Remember that the next biggest jet has only amassed 20 orders within the last 3.5 years, so it's not just an A380 problem. Even if there is some latent demand for VLAs not satisfied by the current planes. Given the timeline of such a potential A380mk2 for a post 2025 EIS, it'd be simple enough for Boeing to use their 777X PiPs, stretch the fuselage to 81/82m and again, get "close" in CASM with a smaller plane, which would leave Airbus in a bind again..


As Matt says apples to oranges:

- CEO had the CATIA disaster
- financial crises
- The CEO was very poorly optimized for it's capacity and has a significant induced drag penalty making it much less competitive compared to it's competion than a 2nd generation A380 will be.
- The aviation market will have grown on more than 20 years.


Matt6461 wrote:
Sure, absent any similarly-efficient competition, an A380X/NWO could sell 1,000 copies, and do so at ~$40mn profit/frame (20mn@500 frames is far too low return for a long-horizon, risky investment. Simply returning cash invested would be a serious program failure for investors and Airbus alike.)


As you can imagine I was calculating added cost per frame. I didn't mention list price. ;)


Matt6461 wrote:
The problem is that a world in which an A380X/NWO sees great market success is a world in which rivals (Boeing but maybe CRAIC/COMAC also) have an opportunity to build a clean-sheet product that beats your A380X/NWO's unit costs at lower capacity level. That's a recipe for capturing the whole market.

This was a much better idea for 2021 EIS (match the 777X's tech investment but greatly exceed its performance delta). By 2026 you'll be competing against much better planes - 787MAX for instance, as well as whatever follows.


My main argument would be that doesn't make a difference for a 850 or 900. Both concepts would face that situation. As we know the bigger the plane the better it's CASM needs to be competitive in the market.

What I question is will the 900 improve CASM enough over a possible 850 to justify it's extra capacity. To me that is doubtful, I suspect a 850 GTF will hit a sweetspot considering the MLG and 80m box/induced drag situation that the 900 will overshoot. I don't have the time, attention span or tools/resources to back that up with thorough calculations. For now I'm okay with that just being my estimation which I admit is not worth that much.



Now back to the the freight situation:

If we compare the LD3 situation between the above 850 and 900 we see the following:

With the 900 you gain 80 – 72,7 = 7,3m. If we divide that by 1,53 m / LD3 we get 4.77 LD3's. Let's round that to 5 LD3's for each side so 10 LD3's. If we then look at the situation after passenger luggage is subtracted (-28 LD3 for the CEO per Leeham), we get + 10 from the stretch – 6 for the extra passengers results in 4 extra LD3's available after passenger luggage. A welcome but not huge addition.

If we now look at the proposed 850 with the rearranged MLG (4-wheel bogey stored more vertically) we see the following. 1.2 LD3 length from redesigning the MLG. An 1.8 LD3 stretch then provides 3 LD3 length worth. So that means 6 LD3's in total. If we deduced 2 extra LD3's needed for the extra passenger's (I counted 42, think that is more realistic than the +50 I mentioned earlier) we get + 6 – 2 = + 4 LD3's positions after passenger luggage.


So after passenger luggage:

900: + 4 LD3's

850: + 4 LD3's


So surprisingly in this calculation the more modest stretch will provide the same extra freight volume after passenger luggage then the full 80m stretch!

This is because of the lower weight allows for a redesign of the MLG. Now I know passengers provide more revenue than freight, but still I think it's important to consider.



Matt6461 wrote:
-I've assumed that the stabilizer's pressure centers didn't move here.


I think you can even gain a few percent extra here cause since their size decreases you can move their centres rearwards at equal rear edge.
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 11:07 am

Taxi645 wrote:
JustSomeDood wrote:
Both the projected sales and development costs seem rather optimistic IMO. The 777X involved far less new stuff (wing + engine) and its rumored to be a 6-7B program, it's hard to imagine a new MLG, wingbox, and empennage not costing at least 5B extra on top of that.


As argued a 850 could share engines with a A330 successor, so yes I think it would be close to $10B.


That depends rather highly on what you believe an A330 sucessor might be.

If it's a widebody taking the 787 head-on in capability, it's engines will be way overbuilt and heavy for your A380X, 500t MTOW needs nowhere near 4x70klbf.

If A intends to make the A330 sucessor a "MoM" product, then maybe, but that presupposes A wants to spend a clean-sheet design tackling this segment when their A32x can be further stretched, much more affordably, for that purpose. (And no, I don't think 4x38klbf works for an A380X either)

Perhaps A could give GE a call, if anyone can make 2 engines lift 500t MTOW it'd be them. It'd be hilarious if the 777X and A380X share the GE9X engine family.

Taxi645 wrote:

JustSomeDood wrote:
The A380 is ten years into EIS and only has 330 total orders, some of which are dubious in nature. 500 orders for an improved version, within a "reasonable" timeline (~10 years after announcement) seems... unlikely. Remember that the next biggest jet has only amassed 20 orders within the last 3.5 years, so it's not just an A380 problem. Even if there is some latent demand for VLAs not satisfied by the current planes. Given the timeline of such a potential A380mk2 for a post 2025 EIS, it'd be simple enough for Boeing to use their 777X PiPs, stretch the fuselage to 81/82m and again, get "close" in CASM with a smaller plane, which would leave Airbus in a bind again..


As Matt says apples to oranges:

- CEO had the CATIA disaster
- financial crises
- The CEO was very poorly optimized for it's capacity and has a significant induced drag penalty making it much less competitive compared to it's competion than a 2nd generation A380 will be.
- The aviation market will have grown on more than 20 years.


-Delays and GFC also plagued the 787 program, that didn't stop it from selling, it only delayed EIS and operations.
-The 777-9 certainly can't be said as poorly optimized and inefficient for its capacity, but it still hasn't sold much at all over the last 3.5 years, in fact, it's order book composition isn't awfully far from the A380s...
-I really don't buy the "aviation market increase == more VLAs" argument, sure, average aircraft size has increased, but at the extremes, there has been a decrease in the flying of 400+seat aircraft and <70 seat aircraft, far improved capacity and yield discipline from airlines has seen to that. It'd take a lot of small upguages between models and increased frequency before the world starts demanding lots of A380-sized aircraft, certainly more than a decade in my estimation.
 
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 11:32 am

JustSomeDood wrote:
That depends rather highly on what you believe an A330 sucessor might be.

If it's a widebody taking the 787 head-on in capability, it's engines will be way overbuilt and heavy for your A380X, 500t MTOW needs nowhere near 4x70klbf.

If A intends to make the A330 sucessor a "MoM" product, then maybe, but that presupposes A wants to spend a clean-sheet design tackling this segment when their A32x can be further stretched, much more affordably, for that purpose. (And no, I don't think 4x38klbf works for an A380X either)


I suspect Airbus will position it's A330 successor between MoM size and 787. Thus a good complement to A321 plus plus and the A350. I suspect around 205T MTOW and between 5.800 and 6.700Nm range depending on capacity. An engine family for such a plane would suit a 2nd gen. 850 just fine.

JustSomeDood wrote:
Perhaps A could give GE a call, if anyone can make 2 engines lift 500t MTOW it'd be them. It'd be hilarious if the 777X and A380X share the GE9X engine family.


I wonder what fan diameter a 505 MTOW twin design requires with 2027 GTF bypass standards? I suspect it would be rather shocking in size.


JustSomeDood wrote:
-Delays and GFC also plagued the 787 program, that didn't stop it from selling, it only delayed EIS and operations.
-The 777-9 certainly can't be said as poorly optimized and inefficient for its capacity, but it still hasn't sold much at all over the last 3.5 years, in fact, it's order book composition isn't awfully far from the A380s...
-I really don't buy the "aviation market increase == more VLAs" argument, sure, average aircraft size has increased, but at the extremes, there has been a decrease in the flying of 400+seat aircraft and <70 seat aircraft, far improved capacity and yield discipline from airlines has seen to that. It'd take a lot of small upguages between models and increased frequency before the world starts demanding lots of A380-sized aircraft, certainly more than a decade in my estimation.


Thus my question: why would and even larger 900 be successful? I think a more moderate stretch at close to the same CASM would be less niche.
Innovation is seeing opportunity before obstacle.
 
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Re: 2025ish A380-900NEO

Mon Jan 29, 2018 7:45 pm

Taxi645 wrote:
What I question is will the 900 improve CASM enough over a possible 850 to justify it's extra capacity. To me that is doubtful, I suspect a 850 GTF will hit a sweetspot considering the MLG and 80m box/induced drag situation that the 900 will overshoot. I don't have the time, attention span or tools/resources to back that up with thorough calculations. For now I'm okay with that just being my estimation which I admit is not worth that much.


The issue isn't simply -900 vs. -850. It's -900NEO (no new wing) versus -850X (new wing), plus development cost/risk of each option. There is no reasonable doubt that an -850X would be a far better product than -900NEO, but it would it cost much more to develop.

Re your estimation method... I don't hold it against you for skipping some of the steps I took in, for example, the OP. But I'd encourage you to develop the tools/time to take these steps. It really doesn't take much math skill - I know because I'm not great at math and still plod through it. I'd prefer one long post and substantive follow-up discussion with a few interested members to a series of a.net arguments... Thanks for such discussion so far.

To return to the merits: If you applied some more steps to your A380+new wing analysis, I think you'd see you're way underestimating that idea's operating economics. First order estimates should be -17.5% delta to SFC, +20% delta to L/D, ~15% delta to OEW (-800X, no stretch). The Breguet equation (simple calc., should be part of your toolkit), gives ~45% lower trip fuel burn and ~425t MTOW for those figures. Now you need only ~50k lb-T engines as a quad or a technically realistic twin with ~110k engines.
 
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Re: 2025ish A380-900NEO

Tue Jan 30, 2018 12:31 am

Taxi645"


[quote="JustSomeDood wrote:
-Delays and GFC also plagued the 787 program, that didn't stop it from selling, it only delayed EIS and operations.
-The 777-9 certainly can't be said as poorly optimized and inefficient for its capacity, but it still hasn't sold much at all over the last 3.5 years, in fact, it's order book composition isn't awfully far from the A380s...
-I really don't buy the "aviation market increase == more VLAs" argument, sure, average aircraft size has increased, but at the extremes, there has been a decrease in the flying of 400+seat aircraft and <70 seat aircraft, far improved capacity and yield discipline from airlines has seen to that. It'd take a lot of small upguages between models and increased frequency before the world starts demanding lots of A380-sized aircraft, certainly more than a decade in my estimation.


Thus my question: why would and even larger 900 be successful? I think a more moderate stretch at close to the same CASM would be less niche.[/quote]

Its a lot easier to recoup 3B by selling 150 frames than recouping 10+B by selling 500 frames, the first option requires the ME3 buy in with A380 replacements, the second.. requires a bit more than that.
 
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Re: 2025ish A380-900NEO

Tue Jan 30, 2018 10:08 am

Matt6461 wrote:
The issue isn't simply -900 vs. -850. It's -900NEO (no new wing) versus -850X (new wing), plus development cost/risk of each option. There is no reasonable doubt that an -850X would be a far better product than -900NEO, but it would it cost much more to develop.


I'll make an argument for a new wing:

- If the A380's wing is overbuilt for the CEO it is certainly overbuilt for a 505T 2nd gen. 850 or even a 900.
- The stubby AR can't effectively/easily addressed with the current wing, while the scope to improve this within the 80m box will grow tremendously with a 2nd gen. with GTF's
- Fuel load, that is carried in the wing, will see an extreme reduction with a 2027 GTF, 505T MTOW and much improved induced drag.
- If ever there was a plane that would benefit from (the weight saving of) a CFRP wing it would be a 2nd gen. A380
- At 2027 wing design will have moved on 22 years from 2005 standards.
- The current wing will require wing twist and winglet changes anyway. While not nearly as expensive, it would reduce the difference somewhat.

In my view the argument to do change the wing is so overwhelming that it does justify the considerable cost.


Matt6461 wrote:
Re your estimation method... I don't hold it against you for skipping some of the steps I took in, for example, the OP. But I'd encourage you to develop the tools/time to take these steps. It really doesn't take much math skill - I know because I'm not great at math and still plod through it. I'd prefer one long post and substantive follow-up discussion with a few interested members to a series of a.net arguments... Thanks for such discussion so far.


As said I don't the time or attention span to get a reliable outcome for which I lack the tools or resources. The result for me is just not worth the effort. I do appreciate others, like yourself, who do make the effort to give these discussions more substance. I also hope Bjorn over at Leeham will have a go at what he thinks would be viable 2nd. Gen. A380 options.


JustSomeDood wrote:
Its a lot easier to recoup 3B by selling 150 frames than recouping 10+B by selling 500 frames, the first option requires the ME3 buy in with A380 replacements, the second.. requires a bit more than that.


What strategic use would that be to Airbus? To have the current production trickle on at a loss to be able to sell it's successor at a tiny segment of the market with a barely profitable production run? A plane competitive for a few years until Boeing comes in at the early 30's with a 777 replacement and take the whole market above the A350?

No Airbus is doing this because it has bigger plans for the A380 in the future.
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Re: 2025ish A380-900NEO

Tue Jan 30, 2018 12:39 pm

Taxi645 wrote:
No Airbus is doing this because it has bigger plans for the A380 in the future.


Airbus problem is that the A380 as a design will turn "outdated". Things move on.
In that respect Boeing has entangled Airbus quite successfully with their FUD campaign.
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Re: 2025ish A380-900NEO

Tue Jan 30, 2018 8:51 pm

It's tough. I think straight A388.5 or A389 NEO (low up-front investment) is the way to go. The more pie-in-sky stuff just doesn't pencil out for this niche product. The only thing that will change between now and 2025 is, slot constraints will become more onerous between certain cities. That force will continue to be the only justification for A380. Otherwise, large twins will continue to beat down the improved A380. The central thesis that CASM is king, and A380 will outcompete twins, was a misconception of how the industry works, and that will not change.
 
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Re: 2025ish A380-900NEO

Wed Jan 31, 2018 8:34 am

WIederling wrote:
Taxi645 wrote:
No Airbus is doing this because it has bigger plans for the A380 in the future.


Airbus problem is that the A380 as a design will turn "outdated". Things move on.
In that respect Boeing has entangled Airbus quite successfully with their FUD campaign.


Surely at some point the A380 concept will turn outdated. However I can't imagine Airbus going through all the trouble and expense with extending the production of the CEO if not for waiting for the right engine and market situation to give the A380 the “massive update” they said they will. That's why I'm arguing a more substantial update, because it will “run out of steam” too soon other wise.


Flighty wrote:
It's tough. I think straight A388.5 or A389 NEO (low up-front investment) is the way to go. The more pie-in-sky stuff just doesn't pencil out for this niche product. The only thing that will change between now and 2025 is, slot constraints will become more onerous between certain cities. That force will continue to be the only justification for A380. Otherwise, large twins will continue to beat down the improved A380. The central thesis that CASM is king, and A380 will outcompete twins, was a misconception of how the industry works, and that will not change.


I think the latter argument itself is a misconception. The CEO was not relatively unsuccesful because CASM is not very important, but because the CASM gap towards the smaller twins was insufficiently large because it was a poorly optimized design waisting it's double decker and economies of scale advantages left and right. With the 2nd generation A380 Airbus won't make that mistake again.


Taxi645 wrote:
I'll make an argument for a new wing:

- If the A380's wing is overbuilt for the CEO it is certainly overbuilt for a 505T 2nd gen. 850 or even a 900.
- The stubby AR can't effectively/easily addressed with the current wing, while the scope to improve this within the 80m box will grow tremendously with a 2nd gen. with GTF's
- Fuel load, that is carried in the wing, will see an extreme reduction with a 2027 GTF, 505T MTOW and much improved induced drag.
- If ever there was a plane that would benefit from (the weight saving of) a CFRP wing it would be a 2nd gen. A380
- At 2027 wing design will have moved on 22 years from 2005 standards.
- The current wing will require wing twist and winglet changes anyway. While not nearly as expensive, it would reduce the difference somewhat.


I'll add one more argument to the above and to why the considerable cost could be justified.

The R&D spent on designing a CFRP wing won't just benefit the A380 itself, but all subsequent programs, for instance the A330 successor I mentioned earlier. Thus (a small) part of the $10B doesn't not need to be allocated towards the A380 2nd gen. program. Together with the knowledge gained from the C-series Airbus will be in a very strong position regarding CFRP wings for their full spectrum of products.
Innovation is seeing opportunity before obstacle.
 
RJMAZ
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Re: 2025ish A380-900NEO

Wed Jan 31, 2018 9:28 am

I applaud your effort on this post :)

Some of these improvements the cost is far too great for the amount of efficiency it provides.

The more money Airbus spends on the A380NEO the more aircraft it must sell to get a return for its investment. It would be wise to rank the improvements on a cost Vs benefit scale.

In my opinion the stretch is the best value for money improvement. It provides A a big percentage increase in seats for a small percentage increase in fuel burn. It also improves CASM significantly. All the other improvements listed should take into account a stretch.

A new lighter carbon wing wouldn't rank high on the cost Vs benefit scale. The current wing we might say is 10% oversized in terms of weight, size and lift. However if a stretch comes it might be only 5% oversize and overweight. So we've halved the amount of improvement that a new carbon wing would provide. So a new wing would drop down in the cost Vs benefit scale.

The landing gear might be overbuilt and overweight but if Airbus decide a stretch is needed then the landing gear might be acceptable in weight.

Wing tips are an obvious improvement of a couple percent and are cheap. So they would rank highly in the cost Vs benefit scale.

Engines are costly. Every year they are improving.
Rolls have the Trent XWB and the Trent 7000 which both have slightly better fuel burn than the current A380's engines. Current developments are the advance and the ultrafan. The advance will be available very soon and is another improved Trent. The ultrafan is a geared fan and might be a decade away.

The advance could allow the A380NEO to fly in 5 years time. It combines the trent families best core and their best fan in one engine. The demo engine is currently running. It would have a big advantage over the 787 and A350 in terms of engine tech for nearly a decade.

The ultrafan is quite a while away but provides a bigger improvement and will more costly. However waiting 10 years means the 787NEO and A350NEO might come out a few years later with similar engine tech.

Thinning the cabin walls would be worst on the cost be benefit scale.

In summary I would do a stretch to 80m, install some new wing tips and put on the more basic Rolls Royce advance engines. The new engines would allow the centre fuel tank to be deleted. This would keep wing bending moment the same even though the fuselage weight has increased with the stretch. No wingbox or wing strengthening mods would be required reducing costs significantly. It would be a cheap 787-10 style stretch not an expensive A350-1000 stretch.
 
WIederling
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Re: 2025ish A380-900NEO

Wed Jan 31, 2018 10:42 am

Taxi645 wrote:
The R&D spent on designing a CFRP wing won't just benefit the A380 itself, but all subsequent programs, for instance the A330 successor I mentioned earlier. Thus (a small) part of the $10B doesn't not need to be allocated towards the A380 2nd gen. program. Together with the knowledge gained from the C-series Airbus will be in a very strong position regarding CFRP wings for their full spectrum of products.


Airbus isn't really short on experience in using composites. historically they are early adopters.
The A380 wing is a laminated layer Al design using quite intriguing forming techniques.
H and V Stab ( NB comparable size are CFRP

The A400M has a CFRP composite wing.
The A350 has a CFRP composite wing.
vast amounts of items ( even very large ones today are out of autoclave / resin infusion.
( largest earliest: rear pressure bulkhead for the A340NG )

A380: the center wingbox fueltank is designed ( Just like A330.) in but has never been used.
nothing to gain. nothing to delete.
Murphy is an optimist
 
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Taxi645
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Re: 2025ish A380-900NEO

Thu Feb 01, 2018 10:15 am

RJMAZ wrote:
A new lighter carbon wing wouldn't rank high on the cost Vs benefit scale. The current wing we might say is 10% oversized in terms of weight, size and lift. However if a stretch comes it might be only 5% oversize and overweight. So we've halved the amount of improvement that a new carbon wing would provide. So a new wing would drop down in the cost Vs benefit scale.

The landing gear might be overbuilt and overweight but if Airbus decide a stretch is needed then the landing gear might be acceptable in weight.


I think you're strongly underestimating the weight saving potential of a 2nd gen. A380 optimized around it's capacity especially with GTF engines.

WIederling wrote:
Taxi645 wrote:
The R&D spent on designing a CFRP wing won't just benefit the A380 itself, but all subsequent programs, for instance the A330 successor I mentioned earlier. Thus (a small) part of the $10B doesn't not need to be allocated towards the A380 2nd gen. program. Together with the knowledge gained from the C-series Airbus will be in a very strong position regarding CFRP wings for their full spectrum of products.


Airbus isn't really short on experience in using composites. historically they are early adopters.
The A380 wing is a laminated layer Al design using quite intriguing forming techniques.
H and V Stab ( NB comparable size are CFRP

The A400M has a CFRP composite wing.
The A350 has a CFRP composite wing.
vast amounts of items ( even very large ones today are out of autoclave / resin infusion.
( largest earliest: rear pressure bulkhead for the A340NG )

A380: the center wingbox fueltank is designed ( Just like A330.) in but has never been used.
nothing to gain. nothing to delete.


I must admit poor argument on my part. On the flip side having the experience limit's the R&D expense needed for a CFRP wing for the A380.


One more argument on the A380 getting outdated at some point. One could argue that the weight saving on fuel load from GTF engines and following weight optimizations actually make the concept of a 10+8 tube within a 80m box (opposed to for instance 9+6 or 10+6) much more viable than it was at launch.
Innovation is seeing opportunity before obstacle.
 
RJMAZ
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Re: 2025ish A380-900NEO

Thu Feb 01, 2018 9:47 pm

Taxi645 wrote:
I think you're strongly underestimating the weight saving potential of a 2nd gen. A380 optimized around it's capacity especially with GTF engines.

I think you underestimate the cost of an optimized A380. A new carbon wing, centre wingbox, engines, landing gear, stretch and tail would easily cost two thirds of a clean sheet design. It may even need to be recertified.

Spending $2 billion for 200 sales is much better than spending $10 billion for 500 sales.
 
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Taxi645
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Re: 2025ish A380-900NEO

Thu Feb 01, 2018 10:37 pm

RJMAZ wrote:
Taxi645 wrote:
I think you're strongly underestimating the weight saving potential of a 2nd gen. A380 optimized around it's capacity especially with GTF engines.

I think you underestimate the cost of an optimized A380. A new carbon wing, centre wingbox, engines, landing gear, stretch and tail would easily cost two thirds of a clean sheet design. It may even need to be recertified.


As said above, I fully realize it will be a costly affair.

RJMAZ wrote:
Spending $2 billion for 200 sales is much better than spending $10 billion for 500 sales.


The cost vs reward reality for a 2nd. generation A380 is a bit more complex than a one-liner.
Innovation is seeing opportunity before obstacle.
 
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Taxi645
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Re: 2025ish A380-900NEO

Fri Feb 16, 2018 10:23 pm

I'll try to briefly explain a bit more why the A380Mk2 vs. 777x situation is quite different from the A380 vs. 773 situation and what the implications are.

Leeham in 2014 published an interesting article on a A380NEO and how it related to the competition:
https://leehamnews.com/2014/02/03/updat ... -involved/


Much of the below contents is based on the tables shown in the above article but adapted to A380Mk2 concept with Ultrafan type engines. The table lists both the 80m A380-900 with the old wing and the 75,5m A380-850 with a new wing and 4-wheel boogie. In the below specification list I'll focus on the A380-850.


The A380-850 specifications:


Image


As you can see despite the small 2,7m stretch the huge fuel saving from a ultrafan type engine and the optimization on the sold capacity allows the MTOW to be reduced from 575t to 505t. This allows for two things:

1 A 4-wheel boogie that saves further weight and cargo space.
2 A significant reduction in induced drag at equal 80m wingspan.


The A380Mk2 vs. The CEO and the 777x:


Image

So anyone who drags out the old and tired well the A380CEO didn't do well so a Mk2 can't do well either is unable to grasp and/or acknowledge the huge difference in fuel seat per mile cost and resulting market dynamics in the 773/A380 (equal at equal seating density) vs. 779/A380Mk2 (-25%) scenario clearly shown in the above table.


Considering development cost and list price of the A380-850:


Development cost: $10Bn
Copies: 500
Cost per plane: $20Mn
10% financing: $22Mn

Additional list price: $55Mn
Current list price: $445,6Mn

New list price: $500,6Mn

If we compare this with the 779 at $425,8Mn, I find $500,6Mn or +17,6% very competitive for a plane that has 53% higher capacity and per seat mile fuel consumption that is 25% lower.


So yes I think an A380-850 will have considerable development cost. However given the above market potential, yes I would consider that development cost worthwhile.
Innovation is seeing opportunity before obstacle.
 
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Matt6461
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Re: 2025ish A380-900NEO

Fri Feb 16, 2018 11:40 pm

Taxi645 wrote:
I'll try to briefly explain a bit more why the A380Mk2 vs. 777x situation is quite different from the A380 vs. 773 situation and what the implications are.


Bravo for putting some numbers to paper. I'll summarize some suggestions/objections and maybe develop more detail later after giving you a chance to respond:

  • You ignore the empennage. Even the belated NEO proposals modified the empennage; this is lower-hanging fruit than MLG/cargo revisions.
  • Your OEM business case model is far too rosy. OEM's need far more than 10% ROI to justify a risky project like this. Aim for at least $3bn annual future profit stream.
  • What's your OEW, L/D, and SFC. You can state the latter two as a ratio to A388. It's impossible to judge the feasibility of a proposal without some reasonable range for those three basic parameters.
  • You're still on this "induced drag" thing. Maybe look back at our TechOps thread on this. L/D is non-dimensional; unrelated to actual weight (with some slight caveats).
  • Please address the relative cost/benefit of rebuilding ~30% of the lower fuselage to enable +6 LD3's. This is a massive revision and cargo just isn't THAT valuable.

Finally, to the extent that you present this as an alternative to an A380NEO, notice that your trip fuel is higher than for my above-sketched A380-900NEO. If I'm right about the -900NEO, why would Airbus spend more to build a worse product?

Of course feel free to tell me I'm dead wrong about the -900NEO. But please show your work.
 
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Matt6461
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Re: 2025ish A380-900NEO

Fri Feb 16, 2018 11:48 pm

Matt6461 wrote:
You're still on this "induced drag" thing. Maybe look back at our TechOps thread on this. L/D is non-dimensional; unrelated to actual weight (with some slight caveats).


One more crack at this, as you seem not to trust me here (don't blame you; I'm open about not being an engineer/expert). Let me try to appeal to your intuition:

If L/D weren't non-dimensional as I claim, then how could a 1/10th scale, basically weightless model, "flying" in a windtunnel, have any predictive merit?

The fact is windtunnels work pretty well; better than anything we can do here and well enough to ground $billions of investment. They have to address the caveat I mentioned above - Reynolds numbers effects. But hopefully the windtunnel picture appeals to some intuitive sense that L/D and weight are basically unrelated.

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