Quoting mjoelnir (Reply 147): I have not seen any data up to now that shows the panel approach to come out heavier than the barrel approach.

I have not seen any data that shows the barrel approach is heavier than the panel approach and I am suspicious. Please share anything you can get your hands on.

Quoting zeke (Reply 148): The 788 is 25-30,000 kg heavier than a 767-300ER with similar capacity.

The 788 is closer in size to the 764 and it flies about 2,000nm further with newer, heavier engines. I would expect it to be a lot heavier.

Quoting astuteman (Reply 149): I'm going to suggest that the Boeing slide uses a kind of "sleight of hand" to make the weight comparison one of MTOW rather than OEW as is implied.

Ding ding ding! Not sure why I didn't think of that. Makes sense now. You're right that it implies something different.

tortugamon

Quoting tortugamon (Reply 141): EK said they chose to pas on an 11-abreast A380 with 18" seats even on regional missions;

That was not a normal 11-abreast A380 with 18" seats. One of the seats was placed considerably higher than the rest, which created a very odd cabin layout, and I imagine a lot of passenger complaints. No airline in their right mind would opt for that.

If Airbus actually created a proper 11-abreast A380 with 18" seats, I have no doubt that EK and many others would jump on it.

Now as for a 10-abreast A350, airlines like EK have shown they are comfortable with 17.5" on regional routes, but I think 16.8" is just too narrow even for them. I don't think you'll see a 10-abreast A350 anywhere outside of airlines which mostly operate charters.

Quoting tortugamon (Reply 150): Quoting mjoelnir (Reply 147): I have not seen any data up to now that shows the panel approach to come out heavier than the barrel approach. I have not seen any data that shows the barrel approach is heavier than the panel approach and I am suspicious. Please share anything you can get your hands on.

I don't think mjoelnir stated the panel approach is lighter, only that it isn't heavier. You posted that it is lighter in post 136,

Quoting tortugamon (Reply 136): One of the benefits of the CFRP tube vs the CFRP panel is weight, not just because of the material but fewer fasteners as well.

The onus is on you to supply the data as that is all he was asking you for.

Quoting zeke (Reply 142): Run the same comparison between the 767 and 787, where the 767 is significantly smaller and lighter and you get ......

That said, you can seat 7 abreast on the 767 and 9 abreast on the 787. The A350 also seats 9 abreast, albeit more comfortably.

So the 787 is a smaller airframe with approximately the same passenger capacity per unit length. But longer 787 frames are less capable than longer A350 frames.

I had reason to take the actual weight of a 789 as delivered and try and compare it against the standard Boeing 3 class seat layout. By trial and error I got a set of seat weights that got me within about 200kg of the comparative OEW of the plane I had the data on and the Boeing standard configuration. I set the 789 without seats weight at ~115t. The spread between the 8 nad the 9 is ~7t so I set the 78X at 122t without seats. For an EK , no crew rest (less 1.4t) , 345-seats ( 80J @80kg and 245Y @22kg ) brought the OEW to 132.5t Adding catering and cabin crew at ~ 4t gives a 136.5 +- DOW.

Quoting tortugamon (Reply 150): I have not seen any data that shows the barrel approach is heavier than the panel approach and I am suspicious. Please share anything you can get your hands on.

You just turned my comment on the head.

The diameter of the fuselage of the A350 is 2.6% wider than the 787.
The 787-10 is 2.1% longer than the A350-900.

If you want to declare a significant weight difference in both fuselage, you imply that the panel design is heavier than the barrel design. Please supply the prove.

So a weight difference can be in the wingbox, MLG, appanage, wing and engines.

The overall height of both frames are similar so I do not thing the vertical stabilizer is bigger on the A350.
And I do not think that the horizontal stabilizer makes a big difference.

Leaves wings, engines, MLG and wing box, and I do not believe you will find 10 t there.

Big part of the bigger fuel volume of the A350 is carried in the larger wings and that should allow a bigger difference between the MZFW and MTOW on the A350 than on the 787.

Quoting aryonoco (Reply 151): That was not a normal 11-abreast A380 with 18" seats. One of the seats was placed considerably higher than the rest, which created a very odd cabin layout, and I imagine a lot of passenger complaints. No airline in their right mind would opt for that.

Fact remains, even without increasing the height, not sure they did btw, the could still do a wider seat that their 777s. They obviously have some hangup and it isn't seat width.

Quoting mjoelnir (Reply 147): Yes I think that because the needed thickness of the CFRP layers is not only dependent on the applied forces but also on the impact resistance in certain areas. That is why there is talk about the narrower fuselage not always getting lighter and a bigger diameter works better against bending and torsion at the same thickness.

....
Here is some info on that:

Quote: Airbus has adopted a 4-shell approach to the composite fuselage of the A350 XWB, meaning that a fuselage section is made by jointing 4 composite panels. Unlike Boeing’s 787 Dreamliner, which adopts an innovative composite barrel, Airbus’ move has already led to overweight problem at this early stage. Boeing 787 Dreamliner’s Carbon Fiber Reinforced Polymer (CFRP) barrel eliminates 1,500 aluminum sheets and 40,000 to 50,000 fasteners. This results in a significant weight reduction. Since the A350 XWB’s panel approach requires fasteners to joint 4 panels into a section, this requires a significant additional amount of fasteners over the 787 Dreamliner. Most importantly, the A350 XWB uses a more conservative type of CFRP than the 787 uses, so if John Leahy claims Boeing’s 787 won’t achieve its weight saving over a conventional airliner, then what will the A350 XWB become? Even John Leahy himself made a contradictory comment shortly thereafter, saying the A350 XWB has a more conventional design. “The A350 test fuselage sections at Hamburg demonstrated a more conventional approach to design and construction, where composites were used in the floor, and the underlying ribs to which composite fuselage panels were attached,” he said. One of the major misconceptions is, the A350 XWB can optimize its material use through different thicknesses of composite panels, whereas the 787 can’t do so due to its use of a CFRP barrel. However, this is very wrong in the way that different “thicknesses” of CFRP can be laid down on the 787’s mold in order to optimize its material usage.

http://www.aspireaviation.com/2009/1...-and-mirrors-show-on-the-a350-xwb/

Quoting mjoelnir (Reply 155): The overall height of both frames are similar so I do not thing the vertical stabilizer is bigger on the A350. And I do not think that the horizontal stabilizer makes a big difference.

Size of the empennage is linked to MTOW. A350 is clearly bigger because in an engine out situation it has more weight it has to shift.

Quoting mjoelnir (Reply 155): The diameter of the fuselage of the A350 is 2.6% wider than the 787. The 787-10 is 2.1% longer than the A350-900.

Drag has to do with wetted area. 2.6% for the entire length of the aircraft is more wetted area than a 2% length stretch.

tortugamon

Quoting tortugamon (Reply 156): Here is some info on that: Quote: Airbus has adopted a 4-shell approach to the composite fuselage of the A350 XWB, meaning that a fuselage section is made by jointing 4 composite panels. Unlike Boeing’s 787 Dreamliner, which adopts an innovative composite barrel, Airbus’ move has already led to overweight problem at this early stage. Boeing 787 Dreamliner’s Carbon Fiber Reinforced Polymer (CFRP) barrel eliminates 1,500 aluminum sheets and 40,000 to 50,000 fasteners. This results in a significant weight reduction. Since the A350 XWB’s panel approach requires fasteners to joint 4 panels into a section, this requires a significant additional amount of fasteners over the 787 Dreamliner. Most importantly, the A350 XWB uses a more conservative type of CFRP than the 787 uses, so if John Leahy claims Boeing’s 787 won’t achieve its weight saving over a conventional airliner, then what will the A350 XWB become? Even John Leahy himself made a contradictory comment shortly thereafter, saying the A350 XWB has a more conventional design. “The A350 test fuselage sections at Hamburg demonstrated a more conventional approach to design and construction, where composites were used in the floor, and the underlying ribs to which composite fuselage panels were attached,” he said. One of the major misconceptions is, the A350 XWB can optimize its material use through different thicknesses of composite panels, whereas the 787 can’t do so due to its use of a CFRP barrel. However, this is very wrong in the way that different “thicknesses” of CFRP can be laid down on the 787’s mold in order to optimize its material usage. http://www.aspireaviation.com/2009/1...-and-mirrors-show-on-the-a350-xwb/

That is not prove that is an opinion piece, for prove you have to do better.

The 787 is lower to the ground, but the overall height difference to the A350 is 0.05 cm. That does not imply a smaller horizontal stabilizer.

All the models of The 787 have the same appanage according to the given numbers. As the rudders are also dependent on the length of the arm, the 787 appanage must be optimized for the 787-8, a quite a bit shorter frame than the A350-900.

Quoting tortugamon (Reply 156): Drag has to do with wetted area. 2.6% for the entire length of the aircraft is more wetted area than a 2% length stretch.

I thought we were talking about weight this time, not drag? Or are you switching the conversation?

[Edited 2015-11-08 19:44:02]

[Edited 2015-11-08 19:47:57]

Quoting tortugamon (Reply 150): I have not seen any data that shows the barrel approach is heavier than the panel approach and I am suspicious. Please share anything you can get your hands on.

We are not talking about barrels, we are talking about aircraft. The load cases for an aircraft are not always dominated by pressurization.

Quoting tortugamon (Reply 150): The 788 is closer in size to the 764 and it flies about 2,000nm further with newer, heavier engines. I would expect it to be a lot heavier.

Even a 764 is the best part of 20,000 kg lighter than a 788, esp the early 788s.

Quoting DocLightning (Reply 153): That said, you can seat 7 abreast on the 767 and 9 abreast on the 787. The A350 also seats 9 abreast, albeit more comfortably.

If you want to talk 7 across in the 767, compare that with 8 across in the 787, and 9 across in A350 if you are looking at comfort levels. If you want to talk about how many pax you can sardine inside a fuselage, talk about 9 across in the 787 and 10 across in the A350.

Quoting tortugamon (Reply 156): Size of the empennage is linked to MTOW.

Wrong, hint look at the DC-10 vs MD-11

Quoting tortugamon (Reply 156): Drag has to do with wetted area.

Wrong, only skin friction drag, not overall drag.

Quoting zeke (Reply 158): If you want to talk 7 across in the 767, compare that with 8 across in the 787, and 9 across in A350 if you are looking at comfort levels. If you want to talk about how many pax you can sardine inside a fuselage, talk about 9 across in the 787 and 10 across in the A350.

The 787 is uncomfortable at 9-abreast. The A350 at 10-abreast would be cruel, being narrower than the 777. No airline is planning on doing that right now, AFAIK.

The fair comparison is based on what is actually used, not what you could cram in.

Quoting DocLightning (Reply 159): The fair comparison is based on what is actually used, not what you could cram in.

10 across in the A350 is an available configuration in the manual, they call it "high efficiency". The seat width is within 0.1" of the 787, it is about 0.5" wider than the seat used in 9 across on the A330.

Quoting mjoelnir (Reply 157): That is not prove that is an opinion piece

It's also six years old and written by one of the more "Boeing centric" bloggers out there.   

Quoting zeke (Reply 160): 10 across in the A350 is an available configuration in the manual, they call it "high efficiency". The seat width is within 0.1" of the 787, it is about 0.5" wider than the seat used in 9 across on the A330.

Yes, but with very thin armrests...

Quoting 817Dreamliiner (Reply 162): Quoting zeke (Reply 160):10 across in the A350 is an available configuration in the manual, they call it "high efficiency". The seat width is within 0.1" of the 787, it is about 0.5" wider than the seat used in 9 across on the A330. Yes, but with very thin armrests...

And it's all marketing , if airlines could fit the A350 with 10 abreast Y with seats just 0,1" narrower than on a 787, most of them would have selected this option. If you believe Airbus' marketing crap, you would also believe Boeing's ridiculous claim the 777X can fit 18" seats 10Y.

Quoting tortugamon (Reply 17): EK and Sir Tim Clark have been very clear and they rarely waffle.

Have a look:

http://www.bloomberg.com/news/articl...until-airbus-can-prove-jet-s-worth

Quote: "Emirates is looking to add 50 to 70 jets for regional services, and would contemplate splitting the order between Boeing and Airbus, he said."

Very clear indeed.

Quoting frigatebird (Reply 163): If you believe Airbus' marketing crap, you would also believe Boeing's ridiculous claim the 777X can fit 18" seats 10Y.

But...they can and they will!! It says so on the tin...it must be true...right?

Quoting frigatebird (Reply 163):

Most I think are using 9 across on the 787 because airlines need to for the brochure economics to work.

Quoting KarelXWB (Reply 164): Very clear indeed.

To be brutally honest, I don't see why this doesn't just happen, obviously they need to drive down the prices, but if he likes the 78X's economics (which he does) but has an issue with its performance on longer sectors (which he seems to) then a split order makes the most sense. I don't normally like the 'everyone's a winner' approach, but this looks like the best option to me.

Quoting enzo011 (Reply 165): "Emirates is looking to add 50 to 70 jets for regional services, and would contemplate splitting the order between Boeing and Airbus, he said." Very clear indeed.

He did previously say that it would be winner takes all, so not really that clear

Quoting fcogafa (Reply 168): He did previously say that it would be winner takes all, so not really that clear

That was a year ago, he must have changed his mind.

If the 787-10 can't cover all regional routes, a split order would sound pretty logical.

Quoting mfranjic (Reply 146): If I have understood correctly, EPA001, You already have a small collection of the selected works composed by mf … Thank You!!

I do. Many thanks for that btw.  .

Quoting KarelXWB (Reply 169): That was a year ago, he must have changed his mind. If the 787-10 can't cover all regional routes, a split order would sound pretty logical.

It seems to be heading in that direction now. But nothing is still certain for this upcoming and eagerly awaited order.

Quoting TheRedBaron (Reply 55):

Quoting tortugamon (Reply 136): You think 13cm wider throughout the entire fuse is going to be negated by 1.5m longer? One of the benefits of the CFRP tube vs the CFRP panel is weight, not just because of the material but fewer fasteners as well. Wing, engine, empennage, and mlg should be heavier IMO. Not the amount quoted below, but heavier:

I think this is obvious for the most part. What is a bit of a mystery is the wire mesh that was put into the barrels for lightning suppression. It was (apparently) underestimated how much was needed, so it is unclear to me if panels, with the lightning conduction built into the subframe, are overall heavier than barrels.

The rest stands to reason, bigger tail, heavier core, bigger wing, fatter fuse, they will add up, not insubstantially.

Quoting zeke (Reply 137): If what your posting is true Airbus would not sell a single A350

The A350 can compete (and win) on newer engine tech (though that will go away soon), larger passenger space (most important, it's why they made it XWB in the first place), customer embedded maintenance processes, price/availability and training. A350 has plenty of other arrows to sling besides weight to win a sale.

Quoting mjoelnir (Reply 157): That is not prove that is an opinion piece, for prove you have to do better.

No, its good enough for me. I don't mind having a different opinion than you. Won't be the last time.

Quoting zeke (Reply 158): Even a 764 is the best part of 20,000 kg lighter than a 788, esp the early 788s.

There is also 2,000nm difference in range. Very different aircraft. This situation is not analogous.

Quoting zeke (Reply 158): Wrong, only skin friction drag, not overall drag.

I didn't say overall drag. Its certainly has an impact.

Quoting scbriml (Reply 161): It's also six years old

I don't think either aircraft have started being assembled differently in that time so I think we're safe

Quoting KarelXWB (Reply 164): Have a look: Quote: "Emirates is looking to add 50 to 70 jets for regional services, and would contemplate splitting the order between Boeing and Airbus, he said." Very clear indeed.

Yep, who can we trust anymore?! If not Sir TC, then who. Ah well.

Quoting fcogafa (Reply 168): He did previously say that it would be winner takes all, so not really that clear

Yes he clearly did.

Quoting KarelXWB (Reply 169): That was a year ago, he must have changed his mind.

Here he is a month ago saying 'one or the other' : "It will be in 2016 – but when, I don't know – and it will be one or the other," he adds.
http://www.flightglobal.com/news/art...n-a350-900-and-787-10-next-417326/

Quoting KarelXWB, reply=169]If the 787-10 can't cover all regional routes, a split order would sound pretty logical.[/quote] What is interesting then is that he is no longer asking for more out of the 78X: "The airline no longer demands further changes to the 787-10 as it “will do most of the world that we want it to do.” http://www.flightglobal.com/news/art...n-a350-900-and-787-10-next-417326/ [quote=justloveplanes (Reply 171): The rest stands to reason, bigger tail, heavier core, bigger wing, fatter fuse, they will add up, not insubstantially.

Exactly. Not sure why we are even arguing this point. Its kind of a slam dunk, its just a matter of it being 6t or 12t or somewhere in the middle.

tortugamon

Quoting zeke (Reply 160): 10 across in the A350 is an available configuration in the manual, they call it "high efficiency".

And if any airline orders that (and gee, I wonder why they haven't?) I defy you to endure it for more than 2-3 hours.

I look forward to reading your TR...

...once the chiropractor straightens you out.

More floor area does not mean you can carry more pax.

The 787 has a fundamentally more efficient fuselage, it has less floor area per row, but can carry the same number of pax per row.

While I do expect a few airlines to go ten abreast on the 350. the seat at sub 17" is just too small, and the other thing is that the aisles are only 15" wide at that narrower seat.

Even a cursory look at airlines shows that for most, pax comfort comes secondary to operating efficiency.

IMO .5 to.8 of an inch per seat is not enough to compensate for the xtra structure which the 350 carries around.

If it is really a straight contest between the 781 and 359 at EK, (and I accept it may not be), the 781 wins clearly as a regional aircraft.

Airbus will have to win this on price or other factors confounding the choice, such as the 380.

Ruscoe

Quoting DocLightning (Reply 173):

It will happen, just like 9 across happens on the A330...MNL-RUH with Cebu Pacific must be the best part of 10 hours. 440 seats on an A330.

See European Leisure Carrier Will Take 10 Abreast A350 (by 817Dreamliiner Nov 9 2015 in Civil Aviation)

Quoting Ruscoe (Reply 174):

Why bother having an rfp if it is as clear cut as the Boeing fanboys make out ?

[Edited 2015-11-09 13:16:31]

Quoting zeke (Reply 175): Why bother having an rfp if it is as clear cut as the Boeing fanboys make out ?

Price Price Price

Ruscoe

Quoting Ruscoe (Reply 176):

If it was clear cut price would not be a factor, as it stands the list price on the -10 is 297.5 where the list on the -900 is 304.8

Quoting zeke (Reply 177): If it was clear cut price would not be a factor, as it stands the list price on the -10 is 297.5 where the list on the -900 is 304.8

Be that, as it may, EK could be looking to squeeze the lowest possible price out of Boeing by going through the motions of floating an RFP to Airbus. -ir

Quoting zeke (Reply 177): If it was clear cut price would not be a factor, as it stands the list price on the -10 is 297.5 where the list on the -900 is 304.8

You are well experienced enough in these matters to know that 1) list price means nothing and 2) small differences in price and/or leverage can sway business. Even if the mission seems to give the 787 a clear advantage, EK will look at the 350 for two reasons: 1) in case Airbus offers a price so good that it can overcome the 787's advantage, and 2) to ensure that Boeing remains aggressive on pricing.

Just look at Delta. They bought 100 x 737-900ER and almost bought 40 more despite the fact that the A321 was quite clearly the better aircraft. The reason is price.

Clark and al Baker just love negotiating via the media. The only surprise I have is when people get wound up and take anything they say as gospel.

Tim Clark knows very well the specs and limitations of every aircraft that is available. He is also very well aware of the efforts and costs associated with creating his dream planes.

I have no doubt that he really, really does want the 781 powered by 84,000lb engines. He also really, really wants those engines to be really, really cheap, or at least not cost him a penny more than the currently available engines and they must also be as reliable.

What he will do, is keep playing Boeing against Airbus, GE against RR, until he gets as much of what he wants as he can...all the while spending a lot of time in the news, getting free advertising for EK.

What I want, is a CT-114 Tutor on floats. I don't think I'm getting one...but wouldn't that be so damned cool?

Quoting tortugamon (Reply 69): Supposedly the gear is the limiting item. No immediate MTOW lift available.

That would explain the 781's 553000 lb. T-O vs the 789's 557000 lb. It never made sense to loose that 4000 lb of fuel load.

Quoting tortugamon (Reply 172): Not sure why we are even arguing this point. Its kind of a slam dunk, its just a matter of it being 6t or 12t or somewhere in the middle.

That the A350-900 weighs more than a 787-10 is indeed a slam-dunk.

But the question as you say is "why are we arguing about it?"
Because what really matters is the fuel burn that is derived from the aircraft configuration and engine efficiency.
Ferpe's model shows the A350-900 burning a fraction less fuel, and (conversely) going a fraction further on each tonne of fuel.
Despite the extra weight

Quoting tortugamon (Reply 172): No, its good enough for me.

It shouldn't be. The Aspire publication is just nonsensical, and dissectable at will.
Because Airbus were already building large CFRP panelled barrels for the A380 tailcone, the move to said panels on the A350 fuselage was a low-risk approach.
That's not the same as being low-tech.
Boeing's journey to the CFRP barrels was much larger.
But I'd challenge anyone to demonstrate that there is any meaningful difference in the weight between the two options..

Quoting justloveplanes (Reply 171): The A350 can compete (and win) on newer engine tech (though that will go away soon), larger passenger space (most important, it's why they made it XWB in the first place), customer embedded maintenance processes, price/availability and training. A350 has plenty of other arrows to sling besides weight to win a sale.

Indeed it can

Rgds

Quoting DocLightning (Reply 159): The 787 is uncomfortable at 9-abreast. The A350 at 10-abreast would be cruel, being narrower than the 777. No airline is planning on doing that right now, AFAIK.

LLC has already released notice of 10x in an A350. I won't get on it and I'm not that big. Probably a 16" isle & 16" seats.

Quoting astuteman (Reply 182): Because what really matters is the fuel burn that is derived from the aircraft configuration and engine efficiency. Ferpe's model shows the A350-900 burning a fraction less fuel, and (conversely) going a fraction further on each tonne of fuel.

We have actual numbers for the 787-9 and A350-900 posted by Chaostheory for his airline and it shows the 787-9 (and, by extension, 787-10) with a fractional advantage (200-400kg per hour over 3000nm) so the A350-900 and 787-10 appear to be effectively identical in terms of fuel burn (at least for regional missions) so the RFP will be influenced by other factors (price, capacity, availability, etc.).

Quoting Stitch (Reply 184): We have actual numbers for the 787-9 and A350-900 posted by Chaostheory for his airline and it shows the 787-9 (and, by extension, 787-10) with a fractional advantage (200-400kg per hour over 3000nm) so the A350-900 and 787-10 appear to be effectively identical in terms of fuel burn (at least for regional missions) so the RFP will be influenced by other factors (price, capacity, availability, etc.).

For the technically challenged like myself is the likely very similar fuel burns for the -9 and -10 due to the fact that weights are essentially the same?? Does having a longer fuselage help or worsen fuel burn, everything else being equal. If the MEW/OEW of the -10 is higher that has no effect on fuel burn unless TOW is higher???

Quoting tortugamon (Reply 172): I don't think either aircraft have started being assembled differently in that time so I think we're safe

In fact the A350 hadn't even begun assembly when the piece was written, so claims about the A350's construction causing weight problems cannot be taken seriously. The fact that batch 3 aircraft will be at target weight shows how overblown the "issue" was.

Quoting trex8 (Reply 185): For the technically challenged like myself is the likely very similar fuel burns for the -9 and -10 due to the fact that weights are essentially the same?

That is what I imagine is the case.

Quoting trex8 (Reply 185): Does having a longer fuselage help or worsen fuel burn, everything else being equal.

I would imagine there would be an additional drag penalty from the longer center fuselage section, but the 787 fuselage is quite smooth due to having fewer fasteners so I expect said penalty is very small.

Quoting astuteman (Reply 182): It shouldn't be. The Aspire publication is just nonsensical, and dissectable at will. Because Airbus were already building large CFRP panelled barrels for the A380 tailcone, the move to said panels on the A350 fuselage was a low-risk approach. That's not the same as being low-tech. Boeing's journey to the CFRP barrels was much larger. But I'd challenge anyone to demonstrate that there is any meaningful difference in the weight between the two options

If there was no weight benefit for the tube vs panel approach than I doubt Boeing would have done it the way that they did. It certainly adds a ton of complexity in production and the repair costs could be more significant. It could ease final assembly I imagine but I can't see this being the primary reason. Certainly at the very least the lack of fasteners contributes to weight loss.

Quoting scbriml (Reply 186): In fact the A350 hadn't even begun assembly when the piece was written

The part I was interested in in the quote was the fewer fasteners part. I don't think that has changed.

tortugamon

Quoting Stitch (Reply 184): We have actual numbers for the 787-9 and A350-900 posted by Chaostheory for his airline and it shows the 787-9 (and, by extension, 787-10) with a fractional advantage (200-400kg per hour over 3000nm) so the A350-900 and 787-10 appear to be effectively identical in terms of fuel burn (at least for regional missions) so the RFP will be influenced by other factors (price, capacity, availability, etc.).

We also have "The Godfather" himself, Hazy chiming in as well.   

“If it’s identically configured, the -10 has a little bit of an edge on the -900,” Udvar-Hazy, 67, chief executive officer of Air Lease Corp., told reporters today at the Paris Air Show after the company agreed to buy 30 of the planes. “The -900 has a little more range, but this has lower fuel burn.”

http://www.bloomberg.com/news/articl...boeing-787-10-beats-airbus-on-fuel

Quoting jacobin777 (Reply 189): We also have "The Godfather" himself, Hazy chiming in as well.

We actually can hear it from the horse's mouth:

"Describing both the A350-900 and 787-10 as “good aeroplanes”, he says the Airbus twinjet would likely have the required performance “but is it as fuel efficient as the -10? Probably not. But the A350 is a heavier aeroplane, it’s got more thrust, more tankage, and it’s designed to fly further [than Emirates needs].”
http://www.flightglobal.com/news/art...etter-hot-performance-from-413281/

If the fuel difference was minimal I would think this wouldn't be too much of a negotiation (in favor of the A359) and we know the A350 has better engines and I assume we can believe the aero is similar. So that really just leaves a weight difference which some seem to be doubting? STC says straight out that it is a heavier airplane.

And again, 85% of EK's flights are under 8 hours and EK says that the 787-10 can fly 8.5 hours without a kink in the (larger than A359) payload.

Interestingly this article also says that the engine is spec'd at 70-72,000lbs yet we know there is a 77,800lbs RR Trent 1000 engine already certified let alone the yet to be certified Trent TEN.

tortugamon

Quoting IslandRob (Reply 178): Be that, as it may, EK could be looking to squeeze the lowest possible price out of Boeing by going through the motions of floating an RFP to Airbus. -ir

Or it could be that the A350 is better than the Boeing fan boys give it credit for. This is the same airline that had previously ordered and cancelled the A350, because we were told on here that the 787 was soooooooooo much better, and yet they are contemplating it.

Quoting seabosdca (Reply 179): ) list price means nothing and 2) small differences in price and/or leverage can sway business.

I disagree with both of those, list price dons mean something, it is the starting point. An airline would be very happy to pay an extra 5-10 million for an airframe that will generate more yield over a 10-20 year life.

Quoting seabosdca (Reply 179): EK will look at the 350 for two reasons:

How about 3) the possibility it is technically better than what the Boeing fanboys on here give it credit for.

Quoting seabosdca (Reply 179): the A321 was quite clearly the better aircraft. The reason is price.

You don't know if the 321 is the better aircraft for DL.

Quoting astuteman (Reply 182): Ferpe's model shows the A350-900 burning a fraction less fuel, and (conversely) going a fraction further on each tonne of fuel.

Just like the 787 vs 767 ....

Quoting trex8 (Reply 185): Does having a longer fuselage help or worsen fuel burn, everything else being equal.

Fuel burn increases, additional drag, CG difference, and airflow into the engine.

Quoting tortugamon (Reply 188): If there was no weight benefit for the tube vs panel approach than I doubt Boeing would have done it the way that they did.

Weight was never the main driver, it was for manufacturing and maintenance.

Quoting tortugamon (Reply 188): Certainly at the very least the lack of fasteners contributes to weight loss.

You have clearly never seen a 787 up close, they have heaps of fasteners.

Quoting tortugamon (Reply 188): The part I was interested in in the quote was the fewer fasteners part. I don't think that has changed.

Its a misconception from one person who is not an engineer being read by another person who is not an engineer, the blind leading the blind. They both need lots of fasteners.

Quoting zeke (Reply 191): 3) the possibility it is technically better than what the Boeing fanboys on here give it credit for.

You neglected that you were responding to a conditional. Sure it may be technically better (although it's hard for me to see how on these missions, given similar fuel burn and lower capacity). My sentence was based on an *assumption* that was not the case.

Quoting zeke (Reply 191): You don't know if the 321 is the better aircraft for DL.

I just go by what Anderson says. He said at one point that he liked the 321 better but that he got a deal he couldn't refuse on the 739ER. I don't think that's much of a surprise to anyone, in any case -- the 321 is the more capable and efficient aircraft at only a slight weight penalty.

Quoting Stitch (Reply 184): We have actual numbers for the 787-9 and A350-900 posted by Chaostheory for his airline and it shows the 787-9 (and, by extension, 787-10) with a fractional advantage (200-400kg per hour over 3000nm) so the A350-900 and 787-10 appear to be effectively identical in terms of fuel burn (at least for regional missions) so the RFP will be influenced by other factors (price, capacity, availability, etc.).

Again, Ferpe's numbers show the 787-9 as being better than the A350-900 (as you suggest) and the 787-10 about the same to a fraction (and a small one at that) worse.
Which seems to be in agreement with your comment , and CT's numbers   

Quoting tortugamon (Reply 188): If there was no weight benefit for the tube vs panel approach than I doubt Boeing would have done it the way that they did.

Where did I say "no" advantage? I said "meaningful".
Where the A350-900 might have an OEW 6-8t higher than the 787-10, I'm willing to bet that only about 200kg of that would disappear if it were made from barrels..

Quoting tortugamon (Reply 188): The part I was interested in in the quote was the fewer fasteners part. I don't think that has changed.

Again, it is unquestionable that too much is made of this. especially by the Aspire article
There are still vast numbers of fasteners in both aircraft to secure the CFRP to the frames.
You only have to look at the photo linked by Zeke
The number of extra fasteners required by 3 long seams is very small in that context.

So why did Boeing go barrels? Because they went for the moonshot and left nothing on the table. Not even c. 200kg (IMO)
Whether that was actually worth it in the end is a question we will never know the answer to.
It unquestionably resulted in a superb aeroplane.
But then so have the panels on the A350  

Quoting tortugamon (Reply 190): If the fuel difference was minimal I would think this wouldn't be too much of a negotiation (in favor of the A359)

Why?
A 787-10 burning about the same fuel as an A350-900 will unquestionably have better fuel burn per seat by dint of it's 3 extra rows.
The question is what other advantages might the A350-900 bring to offset this natural advantage to the 787-10?

Rgds

Quoting zeke (Reply 191): An airline would be very happy to pay an extra 5-10 million for an airframe that will generate more yield over a 10-20 year life.

Its very likely that the 78X would yield more than the A359 for EK over a 10-20 year life.

Quoting zeke (Reply 191): 3) the possibility it is technically better than what the Boeing fanboys on here give it credit for

Do you need your A350-fan stroked or something? The A359 is awesome! Probably the best single widebody model on offer. Right on top of the sweet spot of around 300 seats which is where the average widebody sales has been for 15 years. An impressive EIS and it will be phenomenally successful. Long live the A359!!

It still can't win every order and wont' be ideal for every RFP just like:

Quoting zeke (Reply 191): You don't know if the 321 is the better aircraft for DL.

You don't know the A359 will be better for EK.

Quoting zeke (Reply 191): They both need lots of fasteners.

I didn't think it was held together by super glue. Thanks for the lesson  

tortugamon

Quoting Stitch (Reply 184): We have actual numbers for the 787-9 and A350-900 posted by Chaostheory for his airline and it shows the 787-9 (and, by extension, 787-10) with a fractional advantage (200-400kg per hour over 3000nm) so the A350-900 and 787-10 appear to be effectively identical in terms of fuel burn (at least for regional missions) so the RFP will be influenced by other factors (price, capacity, availability, etc.).

This may very well be correct regarding comparing the 787-9 and 350-900 fuel consumption per hour.

However, if it is correct than it must be that the 787-10 have several percentage points higher fuel consumption for the same stage lenght compared to a 787-9.

We can assume the exact same wing and engine SFC efficiency on both the 787-9 and -10. A 787-9 taking off with a full passenger load and no cargo for a 3000 mile trip will need some amount of fuel and have some specific take off weight for that trip.

Now, for the 787-10 to make the same trip with full passenger load and no cargo it will obviously be heavier before taking aboard any fuel. Fuselage empty weight is maybe 5 tonnes more and it takes some 30 passengers more, more flight attendants, more catering etc. So, say ten tonnes more weight in total before fuel. Then we have a longer fuselage with more wetted area giving more drag. Aproximately 3-4% more wetted area. Wetted area constitutes most of the drag, so 2-3% more drag and fuel consumption from this. Then say we are in the neighborhood of 210 tonnes take off weight for the 787-9 for this mission. Our -10 would be on average 11-12 tonnes heavier throughout the trip. This constitutes an additional induced drag penalty of ca 10 percent. Induced drag beeing less than parasittic drag, this 10 percent increase in induced drag would constitute to about 4 percent increase in required thrust and fuel consumption.

So, in total, a 787-10 will have in the order of at least 6-7 percent higher trip/per hour fuel consumption compared to the 787-9 for a full passenger load over the same 3000 mile trip. At the same time the -10 takes more than 6-7 percent more passengers, so the fuel consumption per passenger will still be a fair bit less compared to the 787-9.

This simple calculation shows that it is completely wrong to assume the -10 will have the same trip or per hour fuel consumption as the -9 based on that those two models have the same maximum take off weight, engines SFC and wing. So, anyone comparing the fuel consumption of a 350-900 and a 787-10 for the same trip lenght can not assume this comparison to be the same as between a 350-900 and a 787-9. The 787-10 will have a significant higher trip fuel burn than a 787-9

Note my distinction between trip fuel burn and per seat fuel burn.

[Edited 2015-11-09 18:42:24]

[Edited 2015-11-09 18:45:43]

Quoting astuteman (Reply 193): Where did I say "no" advantage? I said "meaningful".

True you did. Another poster above...

Quoting astuteman (Reply 193): So why did Boeing go barrels? Because they went for the moonshot and left nothing on the table. Not even c. 200kg (IMO)

Hard to believe they could be so stupid but the 787 program wasn't without other head scratchers. You could be right and it could be about assembly and a tiny amount of weight. Still we are in agreement on the overall weight. My personal believe is closer to the 6-8t difference than the 10t difference but I am very anxious to see where it shakes out. SQ will operate both so maybe that will be our first indication if we can get an inside source.

Quoting astuteman (Reply 193): It unquestionably resulted in a superb aeroplane. But then so have the panels on the A350

Certainly in agreement there.

Quoting astuteman (Reply 193): Why? A 787-10 burning about the same fuel as an A350-900 will unquestionably have better fuel burn per seat by dint of it's 3 extra rows. The question is what other advantages might the A350-900 bring to offset this natural advantage to the 787-10? Rgds

Ah, I meant fuel burn per seat not overall fuel burn. I think the holy grail for Boeing would be to have identical trip cost or lower vs the A359 meaning that everything you gain in cargo and seats is gravy as long as you don't need A359's range' and flexibility. I foresee a long battle in this space. Will be fun to watch.

tortugamon

Quoting zeke (Reply 177): If it was clear cut price would not be a factor, as it stands the list price on the -10 is 297.5 where the list on the -900 is 304.8

The Boeing catalog price comes without engines and other stuff.

A fully equipped 787-10 is more expensive than the A350-900.

Quoting jacobin777 (Reply 189): We also have "The Godfather" himself, Hazy chiming in as well.

You left out the most important piece of information: according to Hazy, the difference between the 78X and A359 in terms of fuel burn is only 1-2%. Not that much to discuss about.

Quoting KarelXWB (Reply 197): You left out the most important piece of information: according to Hazy, the difference between the 78X and A359 in terms of fuel burn is only 1-2%. Not that much to discuss about.

Is that regarding trip fuel burn or per seat fuel burn? If the latter, for how many seats in each plane is the calculation done for?

[Edited 2015-11-10 01:29:06]

Quoting KarelXWB (Reply 197): The Boeing catalog price comes without engines and other stuff.

Actually its not. This is an old graphic, out of the purchase price of US$140 million for a 77W, Boeing only saw 54 million for the airframe. 60 million went to GE.