My motivation for this thread is based on the following article in Flightglobal.

http://www.flightglobal.com/news/art...rgets-year-end-777x-launch-369074/

Summary of changes to B77W to create B777-9X(407 Seats) :

CFRP wings with 234 ft wingspan

MTOW of 753,000 while preserving current payload/range capability of 77W

Engine thrust at 99,500 lbf. with higher bypass and ceramic matrix

Larger wing with its increased lift to drag ratio, coupled with the a 10% improvement in specific fuel consumption for the GE9X engine.

The 777-9X will be 2 meter longer than the 77W, and will have a slightly wider cabin for more comfortable 10Y. The OEW of 777-9X is an estimate that reflects the longer and lighter fuselage due to use of lighter material, higher wingarea, lighter composites for wings, lighter engines, and additional furnishings for the 42 seats.

General Specifications:

....................................A3510.......................B777-9X

Fuselage Length..............242..........................249 feet

Fuselage Width.................19.6........................20.33

Wingspan.......................213..........................234

Wingarea......................4767.........................5050 sq. feet(my estimate)

Seats(3 class).................350..........................407 (210 lbs. per passenger/baggage)

MTOW.....................679,000....................753,000 lbs.

MZFW......................485,000...................525,000

OEW........................335,000...................375,000 (my estimates)

MSP.........................150,000...................150,000

Design Range................8,400.....................8,200 nm (passenger only, and zero cargo)

List Price........................$309......................$320(?) million

Engine Thrust..............97,000...................99,500 lbf

Ratois

OEW/MTOW.....................0.49...........................0.50

OEW/MZFW......................0.69...........................0.71

MTOW/Wingarea............143............................149 (777 has higher wingloading)

MTOW/Thrust....................3.50...........................3.78 (A350-10 has more powerful engines normalised for MTOW)

Under the assumption of a 7,300 nm (LAX-DXB) mission at MTOW:

B777-9X burns about 3,500 gallons more at a current cost of $13,000.

Negligble difference in cargo payload for the above mission length.

B777-9X has the potential to earn about $24,000 in additional 57 seat revenues at 70% load factor.

Overall, B777-9X has a net operating advantage of $11,000 for a 7,300nm mission in 10-abreast 777-9X configuration, and more if one accounts for 7-abreast J class layout of EK, which would be difficult to arrange in A350-1000. This translates to annual operating advantage of nearly $4 million for B777-9X. One can see why EK is excited about 777-9X.

For an operator like CX which is more likely to configure 777-9X in 9-abreast, the numbers for a 6,300nm mission(LAX-HKG) are as follows:

B777-9X burns about 3,000 gallons more at a current cost of $10,500.

Negligble difference in cargo payload for the above mission length.

B777-9X has the potential to earn about $8,000 in additional 18 Y seat(2 meter stretch) revenues at 70% load factor.

A350-1000 has an operating advantage of $2,500 per trip, which is about $1 million annually.

For long dense routes, B777-9X with 9-abreast is at a slight disadvantage against A350-1000. A350-1000 has a trip cost advantage that bodes well for it with operators looking for flexibilty in deploying one aircraft across many types of route profiles, capacity wise .

http://www.flightglobal.com/news/art...rgets-year-end-777x-launch-369074/

Summary of changes to B77W to create B777-9X(407 Seats) :

CFRP wings with 234 ft wingspan

MTOW of 753,000 while preserving current payload/range capability of 77W

Engine thrust at 99,500 lbf. with higher bypass and ceramic matrix

Larger wing with its increased lift to drag ratio, coupled with the a 10% improvement in specific fuel consumption for the GE9X engine.

The 777-9X will be 2 meter longer than the 77W, and will have a slightly wider cabin for more comfortable 10Y. The OEW of 777-9X is an estimate that reflects the longer and lighter fuselage due to use of lighter material, higher wingarea, lighter composites for wings, lighter engines, and additional furnishings for the 42 seats.

General Specifications:

....................................A3510.......................B777-9X

Fuselage Length..............242..........................249 feet

Fuselage Width.................19.6........................20.33

Wingspan.......................213..........................234

Wingarea......................4767.........................5050 sq. feet(my estimate)

Seats(3 class).................350..........................407 (210 lbs. per passenger/baggage)

MTOW.....................679,000....................753,000 lbs.

MZFW......................485,000...................525,000

OEW........................335,000...................375,000 (my estimates)

MSP.........................150,000...................150,000

Design Range................8,400.....................8,200 nm (passenger only, and zero cargo)

List Price........................$309......................$320(?) million

Engine Thrust..............97,000...................99,500 lbf

Ratois

OEW/MTOW.....................0.49...........................0.50

OEW/MZFW......................0.69...........................0.71

MTOW/Wingarea............143............................149 (777 has higher wingloading)

MTOW/Thrust....................3.50...........................3.78 (A350-10 has more powerful engines normalised for MTOW)

Under the assumption of a 7,300 nm (LAX-DXB) mission at MTOW:

B777-9X burns about 3,500 gallons more at a current cost of $13,000.

Negligble difference in cargo payload for the above mission length.

B777-9X has the potential to earn about $24,000 in additional 57 seat revenues at 70% load factor.

Overall, B777-9X has a net operating advantage of $11,000 for a 7,300nm mission in 10-abreast 777-9X configuration, and more if one accounts for 7-abreast J class layout of EK, which would be difficult to arrange in A350-1000. This translates to annual operating advantage of nearly $4 million for B777-9X. One can see why EK is excited about 777-9X.

For an operator like CX which is more likely to configure 777-9X in 9-abreast, the numbers for a 6,300nm mission(LAX-HKG) are as follows:

B777-9X burns about 3,000 gallons more at a current cost of $10,500.

Negligble difference in cargo payload for the above mission length.

B777-9X has the potential to earn about $8,000 in additional 18 Y seat(2 meter stretch) revenues at 70% load factor.

A350-1000 has an operating advantage of $2,500 per trip, which is about $1 million annually.

For long dense routes, B777-9X with 9-abreast is at a slight disadvantage against A350-1000. A350-1000 has a trip cost advantage that bodes well for it with operators looking for flexibilty in deploying one aircraft across many types of route profiles, capacity wise .

- DocLightning
**Posts:**19821**Joined:**

Quoting LAXDESI (Thread starter):B777-9X burns about 3,000 gallons more at a current cost of $10,500.
Negligble difference in cargo payload for the above mission length. B777-9X has the potential to earn about $8,000 in additional 18 Y seat(2 meter stretch) revenues at 70% load factor. |

How come that is 57 additional seats for EK and 18 additional seats for CX?

-Carl Sagan

Quoting DocLightning (Reply 1):How come that is 57 additional seats for EK and 18 additional seats for CX? |

I am assuming that CX will configure B777-9X 9-abreast in Y, whereas EK will configure 10-abreast in Y. The 18 additional seats for CX are due to two additional Y rows on the 777-9X(9 X2) relative to A350-1000.

- DocLightning
**Posts:**19821**Joined:**

Quoting LAXDESI (Reply 2):I am assuming that CX will configure B777-9X 9-abreast in Y, whereas EK will configure 10-abreast in Y. The 18 additional seats for CX are due to two additional Y rows on the 777-9X(9 X2) relative to A350-1000. |

So if there are two additional rows, EK gets 20 extra fares and CX gets 18 extra fares. Assuming $500/ea, EK only gets $10k.

How did you arrive at 57 extra fares for EK?

-Carl Sagan

Quoting DocLightning (Reply 3):How did you arrive at 57 extra fares for EK? |

EK is expected to configure its B777-9X 10-abreast, as its B77Ws are 10-abreast Y. So relative to A358-1000, it will have one extra seat for each Y row(37 seats) and two additional Y rows(20 seats) than A350-1000(marketing comparisons).

How about cargo in terms of not payload but container carrying capability?

- DocLightning
**Posts:**19821**Joined:**

Quoting LAXDESI (Reply 4):EK is expected to configure its B777-9X 10-abreast, as its B77Ws are 10-abreast Y. So relative to A358-1000, it will have one extra seat for each Y row(37 seats) and two additional Y rows(20 seats) than A350-1000(marketing comparisons). |

Ahhh!!! I get it. Thanks.

Your comparison shows that the A3510 seems to be a superior aircraft to the 777 in all but extremely long-range, high-density situations. From your analysis, I wonder why any carrier would order it with the possible exception of EK.

-Carl Sagan

Quoting DocLightning (Reply 7):Your comparison shows that the A3510 seems to be a superior aircraft to the 777 in all but extremely long-range, high-density situations. From your analysis, I wonder why any carrier would order it with the possible exception of EK. |

Air France and Air New Zealand are also 10-abreast in Y. Competitive pressure and a slightly wider Y cabin may entice more airlines to go 10-abreast on 777-9X.

Quoting LAXDESI (Thread starter):Engine thrust at 99,500 lbf. with higher bypass and ceramic matrix.......10% improvement in specific fuel consumption for the GE9X engine. |

Turbojet/turbofan engines use TSFC, not SFC, i.e. the mass of the fuel burned per unit time, per unit thrust. The takeoff thrust is being reduced from 115 klb to 99.5 klb, one would expect a similar reduction in the cruise thrust.

Quoting LAXDESI (Thread starter):Wingarea......................4767 |

I have pointed this on a number of threads, that is the wing area of the -800/-900. The OEWs are also too high.

Quoting LAXDESI (Reply 2):
I am assuming that CX will configure B777-9X 9-abreast in Y, whereas EK will configure 10-abreast in Y. The 18 additional seats for CX are due to two additional Y rows on the 777-9X(9 X2) relative to A350-1000. |

Why is the assumption that the plug will be only aft of the wing ? The 777 today is geometry limited for takeoff and landing, if anything I would see them increasing the length in the forward cabin.

Quoting Stitch (Reply 6):
The 777-9 would add another 4-6 LD3 positions |

I suggest you have a look at the dimensions of an LD-3 again, they are around 60" deep, by implication you are suggesting an increase in the cargo hold of 120-180" (3-4.5m) which is out of proportion compared to the length increase in the aircraft (78 " or 2m).

We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar

Which is why I think if a 2m stretch is all Boeing can get, they shouldn't bother.

- DocLightning
**Posts:**19821**Joined:**

Quoting LAXDESI (Reply 8):
Air France and Air New Zealand are also 10-abreast in Y. Competitive pressure and a slightly wider Y cabin may entice more airlines to go 10-abreast on 777-9X. |

Given a higher yield from the premium cabins, I wonder if the airlines would benefit from the 779X in those classes, as well.

-Carl Sagan

I think it is useful to see how the proposed 777-8X(224 feet) stacks up against A350-1000(242 feet) in EK configuration. Assuming 4-abreast F, 7-abreast J, 10-abreast Y for 777-8X, and 4-abreast F, 6-abreast J, 9-abreast Y for A350-1000, here's what I come up with:

......................................F....................J.......................Y...........Total

B777-8X.....................12.....................35...................260..........307 seats

A350-1000..................12.....................36...................261..........309 seats

Based on my OEW estimate for 777-9X as laid out in OP, I expect the 777-8X to weigh about 35,000 lbs. less than 777-9X at 340,000 lbs., which is about 5,000 lbs. more than A350-1000 at 335,000 lbs.

It seems to me that 777-8X will come up short against A350-1000 on fuel burn per seat even in the most advantageous configuration of EK. Perhaps the shorter model is likely to be 777-8LX for ULH range.

......................................F....................J.......................Y...........Total

B777-8X.....................12.....................35...................260..........307 seats

A350-1000..................12.....................36...................261..........309 seats

Based on my OEW estimate for 777-9X as laid out in OP, I expect the 777-8X to weigh about 35,000 lbs. less than 777-9X at 340,000 lbs., which is about 5,000 lbs. more than A350-1000 at 335,000 lbs.

It seems to me that 777-8X will come up short against A350-1000 on fuel burn per seat even in the most advantageous configuration of EK. Perhaps the shorter model is likely to be 777-8LX for ULH range.

- DocLightning
**Posts:**19821**Joined:**

Quoting LAXDESI (Reply 12):I think it is useful to see how the proposed 777-8X(224 feet) stacks up against A350-1000(242 feet) in EK configuration. |

That's a 6M difference. What about against the A359?

-Carl Sagan

For all you tech types that like running numbers... aeroturbopower has run some of his own if your interested.

http://aeroturbopower.blogspot.com/2...more-than-challenge-a350.html#more

There are some mistakes, but an interesting take.

http://aeroturbopower.blogspot.com/2...more-than-challenge-a350.html#more

There are some mistakes, but an interesting take.

harder than woodpecker lips...

That sure seems like a small thrust difference for that large a MTOW difference.

Anon

Quoting mffoda (Reply 14):For all you tech types that like running numbers... aeroturbopower has run some of his own if your interested.
http://aeroturbopower.blogspot.com/2...#more |

Thanks for the link. As pointed out in the comments section, MTOW numbers are incorrect.

Quoting nomadd22 (Reply 15):That sure seems like a small thrust difference for that large a MTOW difference. |

Some of it is being compensated by the bigger wings of B777-9X. The current 77W has more powerful(normalised for MTOW) engines than the proposed B777-9X. Ratos for all three with ranks in parenthesis:

Ratois.............................A3510.......................B777-9X...................B77W

MTOW/Wingarea............143(1)........................149(2) ........................168(3)

MTOW/Thrust.....................3.50(2).......................3.78(3)........................3.35(1)

The 77W has the most powerful engines(normalised for MTOW) of the three, but also has the highest wingloading. B777-9X at current spec. is expected to have the lowest MTOW/Thrust ratio. As for wingloading, B77W has the highest wingloading and the A350-1000 the lowest.

Both A350-1000 and 777-9X are designed with lower wingloading than B77W, and lower MTOW normalised thrust than B77W.

However, A350-1000 at current spec. has higher normalised thrust than B777-9X, and also a lower wingloading. At a superficial level it seems that B777-9X should need more thrust than is currently being proposed.

Quoting LAXDESI (Thread starter):Seats(3 class).................350..........................407 (210 lbs. per passenger/baggage) |

Your numbers do not add up. If you take EK, they have configured the B777-300ER at 358 seats 3-class config. The extra 7 feet in length for the B777-9X will give at best 3 additional rows of economy, or most likely an extra row of business and a row of economy class seating. So this is from 16 to 30 seats in total.

Quoting panais (Reply 17):Quoting LAXDESI (Thread starter):
Seats(3 class).................350..........................407 (210 lbs. per passenger/baggage) Your numbers do not add up. If you take EK, they have configured the B777-300ER at 358 seats 3-class config. The extra 7 feet in length for the B777-9X will give at best 3 additional rows of economy, or most likely an extra row of business and a row of economy class seating. So this is from 16 to 30 seats in total. |

Maybe the part about 10 accross being more practical.

Anon

Well an EK A350-1000 will have 317 seats (per EK), so the gap between it and a 777-9 will be not insubstantial.

Quoting nomadd22 (Reply 18):Maybe the part about 10 accross being more practical. |

EK is already 10 seats across in economy.

Quoting Stitch (Reply 19):Well an EK A350-1000 will have 317 seats (per EK), so the gap between it and a 777-9 will be not insubstantial |

When did they say that? The 777-300ER and the A350-1000 have the same length. At 9 abreast economy for the entire length of the A350-1000 compared to the 777-300ER which the last 5 rows are at 8 abreast, the A350-1000 in EK configuration should be 337, 20-21 seats less than the 777-300ER. Therefore, the gap with the 777-9 is going to be 36 to 50 seats. I am of the opinion that it will becloser to 36 seat difference.

Quoting panais (Reply 20):When did they say that? The 777-300ER and the A350-1000 have the same length. At 9 abreast economy for the entire length of the A350-1000 compared to the 777-300ER which the last 5 rows are at 8 abreast, the A350-1000 in EK configuration should be 337, 20-21 seats less than the 777-300ER. Therefore, the gap with the 777-9 is going to be 36 to 50 seats. I am of the opinion that it will becloser to 36 seat difference. |

EK long haul 77W is configured with 304 Y seats, which is about 30 rows. At 9-abreast, A350-1000 will have about 30 less Y seats.

I think it will be difficult to fit the current 77W 7-abreast J seats(6 rows) on to A350-1000, leading to a loss of 6 J seats on A350-1000. That is a total loss of 36 seats on A350-1000 relative to EK 77W(358 seats), leaving it with nearly 322 seats, which is very close to Stitch's figure of 317 seats for EK A350-1000.

Quoting panais (Reply 20):When did they say that? |

March 2008 - EK Vice President of Route and Fleet Planning Richard Jewsbury

Quoting panais (Reply 20):The 777-300ER and the A350-1000 have the same length. |

True, but EK fits 10-abreast in the 777-300ER and will fit 9-abreast in the A350-1000. So the 777-300ER gains one extra seat per row of Economy.

Quoting LAXDESI (Reply 21):EK long haul 77W is configured with 304 Y seats, which is about 30 rows. At 9-abreast, A350-1000 will have about 30 less Y seats. |

I really hope that you are not dividing 304 by 10 to make the statement of ...30 rows. EK 77Ws have more than 40 rows of seating. Also , according to the EK website, 77W is 338 seats in regular 3 class seating and 304 seats with private suites.

Quoting LAXDESI (Reply 21):I think it will be difficult to fit the current 77W 7-abreast J seats(6 rows) on to A350-1000, leading to a loss of 6 J seats on A350-1000. |

It is an opinion. They have 7 seats across on the A332 and it is a good product. With the A350 being wider, this will give them another 2.5 inches of width per seat. EK is great at squeezing space with a premium product offering.

Quoting Stitch (Reply 22):True, but EK fits 10-abreast in the 777-300ER and will fit 9-abreast in the A350-1000. So the 777-300ER gains one extra seat per row of Economy. |

Totally agree. therefore, you should be looking at the economy seating difference taking into consideration that EK's 77Ws have 4-8 abreast in the last 4-5 rows.

Quoting LAXDESI (Reply 21):relative to EK 77W(358 seats), |

EK does not seem to agree with this number. More information at http://www.emirates.com/cy/English/f...ng/our_fleet/boeing_777_300ER.aspx

Quoting LAXDESI (Reply 21):leaving it with nearly 322 seats, which is very close to Stitch's figure of 317 seats for EK A350-1000. |

Therefore I stand correct when I am saying that the difference is 20 -21 seats. 338 for today's EK 77W compared to Stitch's 317 is 21 seats.

Quoting Stitch (Reply 22):March 2008 - EK Vice President of Route and Fleet Planning Richard Jewsbury |

You are aware that this statement was more than 4 years ago, there has not been any update or confirmation and you are the only one who keeps quoting it in the last 4 years.

On August 2011 an article at ATW states that "Emirates is drawing up a new configuration plan for the A350-1000 taking advantage of new and more compact galley technology that lifts the seat count to 340" which is an extra 23 seats. EK can do the same with the 77W and add another 2 rows, which fits with what Airbus is saying that the EK 77W is about 15 seats larger than the EK A350-1000.

Quoting panais (Reply 17):Your numbers do not add up. |

Those numbers are based on Boeing's and Airbus' claims. With the 777-9X being longer than the A350-1000, and wider, thus enabling 10-abreast Y and 7-abreast J, it's not inconceivable that the 777-9X will carry substantially more passenger than the A350-1000. Assuming that the 777-9X can fit 3 more rows of economy - that's 30 seats. Then add 1 extra seat per row over 27 rows of Y class seating and you have 57 seats additional seats all up.

Quoting panais (Reply 17):If you take EK, they have configured the B777-300ER at 358 seats 3-class config. The extra 7 feet in length for the B777-9X will give at best 3 additional rows of economy, or most likely an extra row of business and a row of economy class seating. So this is from 16 to 30 seats in total. |

An additional row of economy and an additional row of business class in EK's configuration is 17 seats, not 16. Therefore, the projected total seats for the 777-9X in EK's configuration would be around 374-388 seats, which is still substantially more than the A350-1000's 317.

Quoting panais (Reply 23):They have 7 seats across on the A332 and it is a good product. |

Their A332's J class product is not the same product as on their 77Ws. The product on their A332s is their old regional product.

Quoting panais (Reply 23):EK does not seem to agree with this number. More information at |

That link clearly shows that one of their 3-class 77W configurations add up to 358 seats.

Quoting panais (Reply 23):Therefore I stand correct when I am saying that the difference is 20 -21 seats. 338 for today's EK 77W compared to Stitch's 317 is 21 seats. |

Where did you get 338 seats from?

Boeing 777 fanboy

Quoting CXB77L (Reply 24):it's not inconceivable that the 777-9X will carry substantially more passenger than the A350-1000. |

Nobody is arguing that the 777-9X will not carry substantially more passengers.

Quoting CXB77L (Reply 24):Assuming that the 777-9X can fit 3 more rows of economy - that's 30 seats. Then add 1 extra seat per row over 27 rows of Y class seating and you have 57 seats additional seats all up. |

I do not think that you can get more than 3 economy rows and this might be a stretch. The length of the 777-9x over the 777-300ER is 79.2 inches. EK has 34 inch economy legroom. That means 2.3 rows. But then again EK is really the Ryanair of longhaul so I would not be surprised if they go to 30 inch legroom slimline seats like LH and squeeze more seats.

Quoting CXB77L (Reply 24):Where did you get 338 seats from? |

I have no idea. I counted the seats again and they are more. Maybe my eyes are playing games with me. Apologies for that.

Quoting panais (Reply 23):On August 2011 an article at ATW states that "Emirates is drawing up a new configuration plan for the A350-1000 taking advantage of new and more compact galley technology that lifts the seat count to 340" which is an extra 23 seats. |

ATW Online picked a fine time to have a web server crash, but I did find a cached copy of that article (from August 1st), so thank you (but I will note that it was 317 seats up until that galley change so Mr. Jewbury's comments were still valid over three years after he made them). I will also note that when those same galleys are fitted on the 777-300ER (and 777X), they will add two more rows of Economy seating (so 20 seats).

Quoting Stitch (Reply 26):ATW Online picked a fine time to have a web server crash, but I did find a cached copy of that article (from August 1st), so thank you (but I will note that it was 317 seats up until that galley change so Mr. Jewbury's comments were still valid over three years after he made them). I will also note that when those same galleys are fitted on the 777-300ER (and 777X), they will add two more rows of Economy seating (so 20 seats). |

In summary, with the new galleys fitted on all three, here's what I get:

A350-1000.......340 seats

B77W...............378(358 +20)

B777-9X...........398(2 additional Y rows over B77W)

The difference between 777-9X and A350-1000 in EK configuration with compact galleys is 58 seats, which is almost the same as marketing difference of 57 seats in OP.

So, where is the usual disclaimer, that this many seats are obviously only helpful, if you can fill them...

Quoting nicoeddf (Reply 28):So, where is the usual disclaimer, that this many seats are obviously only helpful, if you can fill them... |

Trip cost is what really matters. If the 777-9 could hypothetically match the A350-1000's trip cost, then those extra seats effectively can't hurt you if they are not filled (but do help you if they are).

Quoting Stitch (Reply 29):Trip cost is what really matters. If the 777-9 could hypothetically match the A350-1000's trip cost, then those extra seats effectively can't hurt you if they are not filled (but do help you if they are). |

And that is never going to happen, the 777 is carrying too much weight, and will always have more drag, it is a physically bigger tube.

The squabbling about seats above is pointless, we saw in the many 787 vs A330 "Analysis" which like this "Analysis" is next to useless when one looks at the actual seat configurations that airlines will operate the aircraft long distance. No 777 with 400ish seats is going to go anywhere with any sort of payload under the floor, let alone normal catering and passenger baggage. The seat count will be reduced to make way for range/payload.

We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar

- rheinwaldner
**Posts:**1261**Joined:**

Quoting Stitch (Reply 29):If the 777-9 could hypothetically match the A350-1000's trip cost |

This will not happen. As simple as that.

The 777X will need every additional seat to be cramped in, to become competitive per seat. That's why it will be about as successful as a 300 or 350 seater, as the A358 will be as 250 seater...

Quoting zeke (Reply 30):And that is never going to happen... |

Quoting rheinwaldner (Reply 31):This will not happen. As simple as that. |

I'm aware of that, gentlemen, hence my use of the word "hypothetical".

I was just illustrating that you don't have to fill every seat in order to justify a larger plane.

[Edited 2012-05-07 08:35:16]

Quoting Stitch (Reply 32):I'm aware of that, gentlemen, hence my use of the word "hypothetical" |

"hypothetical" can be used to suggest it is based upon unproven fact, it maybe possible. I have clarified that such a hypotheses is impossible to obtain for the 777, but not impossible for a new generation twin.

We are addicted to our thoughts. We cannot change anything if we cannot change our thinking – Santosh Kalwar

Re seats etc, here a more useable measure on how the -1000 and -8X and -9X differ:

Aircraft.............................A350-1000.......777-300ER..........777-8X.......777-9X

Seating, 3 class typical.........350..................365..................353............407

Fuselage length....................73,9.................73,9.................68,6...........76,5

Fuselage wetted area m2......1250................1286.................1182..........1337

Maximum cabin width...........5,61.................5,87..................5,97...........5,97

Cabin lenght........................58,8.................58,5...................53,3...........61,1

Cabin floor m2....................329,8................343,4.................318,0.........364,7

As can be seen the 777X is an interesting frame for those airlines that is prepared to go to 10 abrest, if not the -1000 is better from a cabin perspective. Here frame level data I got from my A vs B wing thread:

Aircraft.............................787-10.......A350-900.....A350-950...A350-1000N....777-8X......777-9X

EIS....................................2018............2014...........2018...........2017............2019.........2019

MTOW.kg...........................250.837......268.000.......268.000......308.000........315.247....344.277

MZFW................................188.000......192.000.......202.000......220.000........225.000....245.000

MSP.....................................56.000........57.000........59.000........68.000.........67.000......73.000

OEW..................................132.000.......135.000......143.000......152.000........158.000....172.000

OEW/MTOW..........................0,526...........0,504.........0,535..........0,494...........0,500........0,500

Seating, 3 class typical.........320.............314.............350............350..............353...........407

Spec range model nm .........6.700..........8.100...........6.700.........8.400...........8.600........8.500

FF kg/hr.............................5.700..........5.700...........5.800.........6.500...........6.500.........7.000

FF kg/nm/per Pax..............0,0365........0,0370.........0,0350.........0,0370..........0,0370......0,0350

The only reason the 777X is competitive (-8X) but not better then the -1000 on a fuel burn level is because it can compensate higher weights with one later engine generation (-2% TSFC). The -8X cabin is more cramped however, if you don't accept to stuff the Y people it will not work, the -9X has the same base for working, if you put people 9 abrest you end up burning 0.0380 level kg/nm/pax ie beyond the -1000 (the -950 is a proposal by CM in the -1000 Ethiad cancellation thread, interesting economy ).

A note about the weights, the -8X and 9X have the 71m wing, other wings does not work for the -8X. That is an extra 6m span and 10m2 area, add new engines with higher PR and the CFRP wing+engines will weight more then the 77W. The extra lenght fuselage eats up the Al Li gain for the -9X as well, the seating then brings 2 etra tons.

[Edited 2012-05-08 08:12:06]

Aircraft.............................A350-1000.......777-300ER..........777-8X.......777-9X

Seating, 3 class typical.........350..................365..................353............407

Fuselage length....................73,9.................73,9.................68,6...........76,5

Fuselage wetted area m2......1250................1286.................1182..........1337

Maximum cabin width...........5,61.................5,87..................5,97...........5,97

Cabin lenght........................58,8.................58,5...................53,3...........61,1

Cabin floor m2....................329,8................343,4.................318,0.........364,7

As can be seen the 777X is an interesting frame for those airlines that is prepared to go to 10 abrest, if not the -1000 is better from a cabin perspective. Here frame level data I got from my A vs B wing thread:

Aircraft.............................787-10.......A350-900.....A350-950...A350-1000N....777-8X......777-9X

EIS....................................2018............2014...........2018...........2017............2019.........2019

MTOW.kg...........................250.837......268.000.......268.000......308.000........315.247....344.277

MZFW................................188.000......192.000.......202.000......220.000........225.000....245.000

MSP.....................................56.000........57.000........59.000........68.000.........67.000......73.000

OEW..................................132.000.......135.000......143.000......152.000........158.000....172.000

OEW/MTOW..........................0,526...........0,504.........0,535..........0,494...........0,500........0,500

Seating, 3 class typical.........320.............314.............350............350..............353...........407

Spec range model nm .........6.700..........8.100...........6.700.........8.400...........8.600........8.500

FF kg/hr.............................5.700..........5.700...........5.800.........6.500...........6.500.........7.000

FF kg/nm/per Pax..............0,0365........0,0370.........0,0350.........0,0370..........0,0370......0,0350

The only reason the 777X is competitive (-8X) but not better then the -1000 on a fuel burn level is because it can compensate higher weights with one later engine generation (-2% TSFC). The -8X cabin is more cramped however, if you don't accept to stuff the Y people it will not work, the -9X has the same base for working, if you put people 9 abrest you end up burning 0.0380 level kg/nm/pax ie beyond the -1000 (the -950 is a proposal by CM in the -1000 Ethiad cancellation thread, interesting economy ).

A note about the weights, the -8X and 9X have the 71m wing, other wings does not work for the -8X. That is an extra 6m span and 10m2 area, add new engines with higher PR and the CFRP wing+engines will weight more then the 77W. The extra lenght fuselage eats up the Al Li gain for the -9X as well, the seating then brings 2 etra tons.

[Edited 2012-05-08 08:12:06]

Non French in France

Quoting ferpe (Reply 34):
Aircraft.............................787-10.......A350-900.....A350-950...A350-1000N....777-8X......777-9X EIS....................................2018............2014...........2018...........2017............2019.........2019 MTOW.kg...........................250.837......268.000.......268.000......308.000........315.247....344.277 MZFW................................188.000......192.000.......202.000......220.000........225.000....245.000 MSP.....................................56.000........57.000........59.000........68.000.........67.000......73.000 OEW..................................132.000.......135.000......143.000......152.000........158.000....172.000 OEW/MTOW..........................0,526...........0,504.........0,535..........0,494...........0,500........0,500 Seating, 3 class typical.........320.............314.............350............350..............353...........407 Spec range model nm .........6.700..........8.100...........6.700.........8.400...........8.600........8.500 FF kg/hr.............................5.700..........5.700...........5.800.........6.500...........6.500.........7.000 FF kg/nm/per Pax..............0,0365........0,0370.........0,0350.........0,0370..........0,0370......0,0350 |

Quoting ferpe (Reply 34):if you don't accept to stuff the Y people it will not work, the -9X has the same base for working, if you put people 9 abrest you end up burning 0.0380 level kg/nm/pax ie beyond the -1000 |

Thanks for the numbers. Your assessment of 9-abreast A350-1000 being better than 9-abreast B777-9X matches what my model indicates as laid out in the OP.

My estimates on OEW and MTOW for B777-9X are about 4,000-5,000 lbs. less than your estimates. Furthermore, my estimate of FF difference between B777-9X and A350-1000 is about 11%, whereas your numbers indicate a difference of 8%.

If your numbers on FF turn out to be correct, B777-8X in EK configuration(10-abreast Y, 7-J, 6-F) is nearly on par with A350-1000--except for LD3 positions.

Quoting ferpe (Reply 34):
Aircraft.............................787-10.......A350-900.....A350-950...A350-1000N....777-8X......777-9X EIS....................................2018............2014...........2018...........2017............2019.........2019 MTOW.kg...........................250.837......268.000.......268.000......308.000........315.247....344.277 MZFW................................188.000......192.000.......202.000......220.000........225.000....245.000 MSP.....................................56.000........57.000........59.000........68.000.........67.000......73.000 OEW..................................132.000.......135.000......143.000......152.000........158.000....172.000 OEW/MTOW..........................0,526...........0,504.........0,535..........0,494...........0,500........0,500 Seating, 3 class typical.........320.............314.............350............350..............353...........407 Spec range model nm .........6.700..........8.100...........6.700.........8.400...........8.600........8.500 FF kg/hr.............................5.700..........5.700...........5.800.........6.500...........6.500.........7.000 FF kg/nm/per Pax..............0,0365........0,0370.........0,0350.........0,0370..........0,0370......0,0350 |

Back of the envelope calculations based on your estimates:

B777-9X(at MTOW) carries 11.7% more weight while burning only 7.6% more fuel per hour than A350-1000N--a gain of about 4%. As you have indicated, 2% is accounted for by relative advantage of newer engines on 777-9X over TXWB engines on A350-1000N.

I am still trying to get my head around the remaining 2% advantage of B777-9X. Perhaps Boeing 777-9X has a better wing(design, aspect ratio) that is able to generate the remaining 2%. Time will tell.

Quoting LAXDESI (Reply 35):My estimates on OEW and MTOW for B777-9X are about 4,000-5,000 lbs. less than your estimates. Furthermore, my estimate of FF difference between B777-9X and A350-1000 is about 11%, whereas your numbers indicate a difference of 8%. |

Here my reasoning around the weight:

WING

The wing weighs typically 12.5% of the MTOW,. CFRP ideally buys you if you can change 100% of the wing weight 20%, but your can't, tank equipment etc is not CFRPs, some ribs might be AlLi etc. Damage tolerance for outer skins etc also reduces your practical gains. Wing size increases 10% and engines get heavier as pressure ratios increase 50% (40 to 60). MLG can be a tad lighter (from 352t to 344) but the RR engine is larger dia so it might be a wash. In the end your are lucky if the wing + engines + MLG weighs the same as the 77W, most likely slightly heavier.

FUSELAGE

Fuselage structure is about 10%, AlLi buys you 5% for the parts you can change, say 2/3 so you gain about 1t. The frame is 2.6m longer however and each m cost you something like 1.5t. Finally those 47 extra Pax nead to sit and eat so that cost you (if all are Y) another ton.

All things counted B have done a great job if the -9X is only 4t heavier then the 77W.

Non French in France

Quoting ferpe (Reply 37):Fuselage structure is about 10% |

Quoting ferpe (Reply 34):
Aircraft.............................A350-1000.......777-300ER..........777-8X.......777-9X Seating, 3 class typical.........350..................365..................353............407 Fuselage length....................73,9.................73,9.................68,6...........76,5 Fuselage wetted area m2......1250................1286.................1182..........1337 Maximum cabin width...........5,61.................5,87..................5,97...........5,97 Cabin lenght........................58,8.................58,5...................53,3...........61,1 Cabin floor m2....................329,8................343,4.................318,0.........364,7 |

The 777-8X fuselage is shorter by nearly 11%. Applying your 10% rule on fuselage structure, and assuming no change in wings and MLG, B777-8X should be about 4 ton lighter, whereas your estimates show it to be 14 ton lighter than B777-9X?

What way is the B777-8X different than B777-9X?

Quoting LAXDESI (Reply 38):The 777-8X fuselage is shorter by nearly 11%. Applying your 10% rule on fuselage structure, and assuming no change in wings and MLG, B777-8X should be about 4 ton lighter, whereas your estimates show it to be 14 ton lighter than B777-9X?
What way is the B777-8X different than B777-9X? |

The -8X has another parent structure, the 287t -200ER. There is not point in downsizing a 352t structure to a 315t -8X, also upsizing the -200ER 28t is also questionable with such methods. For the -9X it is a 2.6 m stretch and a modes 8t decrease of MTOW, there one can apply such rules if one also checks the OEW/MTOW ratio for reason. For the -8X I have gone on the OEW/MTOW ratio for the 777 (about 0.48) but the engines are heavier (50% in PR) and the wing is larger, therefore I have kept the -9X ratio also for the -8X, it will be close to 0.50 for both of these, give or take 0.5% IMO.

The new engines and wings lowered fuel burn reduces the fuel fraction so much that the ratios goes towards 0.50 rather then the old state of the art 0.48.

Non French in France

Quoting ferpe (Reply 39):The -8X has another parent structure, the 287t -200ER. |

IMO, Boeing is likely to use the same wing and MLG on B777-8X and B777-9X.

B77W is 14% longer than B772LR and weighs 14% more(OEW). B772LR's MTOW is just 4 ton(1%) less than that of B77W. B772LR has an OEW/MTOW ratio of 0.42.

If the B777-8X has the same engines, wings, and MLG as B777-9X, then effectively it is a B777-8XLR. Assuming it to be XLR, it should weigh about 11% less than B777-9X(going by B772LR to B77W comparison)--about 19 tons less than B777-9X. This brings the OEW of B777-8X very close to that of A350-1000.

B777 -8XLR should have a range of about 10,000 nm, which should make SYD-LHR non-stop(9,200 nm) more likely.

Quoting LAXDESI (Reply 40):B77W is 14% longer than B772LR and weighs 14% more(OEW). B772LR's MTOW is just 4 ton(1%) less than that of B77W. B772LR has an OEW/MTOW ratio of 0.42.
If the B777-8X has the same engines, wings, and MLG as B777-9X, then effectively it is a B777-8XLR. Assuming it to be XLR, it should weigh about 11% less than B777-9X(going by B772LR to B77W comparison)--about 19 tons less than B777-9X. This brings the OEW of B777-8X very close to that of A350-1000. B777 -8XLR should have a range of about 10,000 nm, which should make SYD-LHR non-stop(9,200 nm) more likely. |

This was in the original article by John Ostrower, it has since been refuted by Jim Albaugh in an interview with Flightglobal, B has no interest in doing a follow up to 200LR, the -8X and the -9X are aimed at the mainline "8000nm" market and the -8X has a 315t MTOW. You can't make a -8XLR on a MTOW of 315t, it will fall out of the sky after 8600nm .

Thus to base it on the 200LR fuselage you would have to reduce dimensions on every single part being made for the flightloads of the 200LR (352t). In essence it will be a 777 fuselage but stressed from the beginning for the 315t case. The wing, engines will be the same (but the wing restressed) as the -9X, the MLG need to be a lighter variant.

My point is in such a case any extrapolations up or down is more error prone then the natural law that all frames are certified and stressed to the same standards. The ULH ones then end up at between 49-51% if they employ the new engine generations and the "mid range" or really long to midrange ones (333, 7810...) end up between 51-53%,

this all being just my .

Non French in France

Quoting LAXDESI (Reply 40):Assuming it to be XLR, it should weigh about 11% less than B777-9X(going by B772LR to B77W comparison)--about 19 tons less than B777-9X. This brings the OEW of B777-8X very close to that of A350-1000. |

The 77L/77W fuselage mass is around 2230 kg/m, the A350 fuselage is around 90% less per meter.

Based upon the additonal fuselage length alone the additional 2.64 m of the 777-9X would make that fuselage 5.9t heavier than the 77W, and the 777-8X being 5.26 m shorter, would make it around 11.7 t lighter than the 77W. This does not include the proposed high denisty seating which will drive up OEW as well.

I also think the 777-8X/9X wing will be heavier than the current 777 wing, not lighter.

- OldAeroGuy
**Posts:**3208**Joined:**

Quoting zeke (Reply 42):The 77L/77W fuselage mass is around 2230 kg/m, the A350 fuselage is around 90% less per meter. |

Are you sure the A350 fuselage only weighs 223 kg/m? Seems a bit light, since that would be about 12.5 lb/in.

Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis

Quoting OldAeroGuy (Reply 43):
Are you sure the A350 fuselage only weighs 223 kg/m? |

No, typo on part, 90% of what the 777 does.

It is line with the gross error check of 90% of the volume per meter, which would be the about the same mass if one assumes a similar density.

Quoting ferpe (Reply 41):You can't make a -8XLR on a MTOW of 315t, it will fall out of the sky after 8600nm . |

I wasn't suggesting an MTOW of 315t.

My comments on B777-8XLR implied an MTOW closer to that of B777-9X. It may be that it will build B777-8X and not XLR.

Edited to delete incorrect MTOW weight on B772ER.

[Edited 2012-05-10 20:03:54]

- OldAeroGuy
**Posts:**3208**Joined:**

Quoting zeke (Reply 44):No, typo on part, 90% of what the 777 does. |

It also matches the 9 A/B (A350) vs 10 A/B (777X) Y class seating.

Airplane design is easy, the difficulty is getting them to fly - Barnes Wallis

Quoting zeke (Reply 44):Quoting OldAeroGuy (Reply 43):
Are you sure the A350 fuselage only weighs 223 kg/m? No, typo on part, 90% of what the 777 does. It is line with the gross error check of 90% of the volume per meter, which would be the about the same mass if one assumes a similar density. |

Are you analyzing weight divided by length? That is a very strange metric to compare airplanes since less than half the weight of the airplane is fuselage structure. An empty fuselage tube is about 25-35% of the weight of the airplane (from what I have been told). The rest is the wing, systems, empennage, landing gear, etc which does not depend on length of the airplane.

LAXDESI was comparing OEW/MTOW which is a very useful comparison. Length to weight would indicate that the 757-300 would be a best selling airplane. I've never seen length to weight ever compared in my engineering experience in aviation.

[Edited 2012-05-11 16:27:11]

If you have never designed an airplane part before, let the real designers do the work!

Quoting Roseflyer (Reply 47): |

Not when one is looking at aircraft that have fuselage plugs added/removed to change capacity. It is easy to estimate the OEW change due to the plugs as the remainder of the aircraft often changes little.

I guess I just don't get it.

This new 777 weighs just a little less than the current 77w but has substantially less power.

What am I missing ?!

This new 777 weighs just a little less than the current 77w but has substantially less power.

What am I missing ?!

The best contribution to safety is a competent Pilot.