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A350-100 Versus B777-9X(407 Seats) Analysis  
User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Posted (2 years 4 months 2 weeks 6 days 21 hours ago) and read 21135 times:

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 .

74 replies: All unread, showing first 25:
 
User currently offlineDocLightning From United States of America, joined Nov 2005, 19371 posts, RR: 58
Reply 1, posted (2 years 4 months 2 weeks 6 days 17 hours ago) and read 21093 times:

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?


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 2, posted (2 years 4 months 2 weeks 6 days 16 hours ago) and read 21082 times:

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.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19371 posts, RR: 58
Reply 3, posted (2 years 4 months 2 weeks 6 days 16 hours ago) and read 21076 times:

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?


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 4, posted (2 years 4 months 2 weeks 6 days 16 hours ago) and read 21071 times:

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).


User currently offlineCX Flyboy From Hong Kong, joined Dec 1999, 6582 posts, RR: 55
Reply 5, posted (2 years 4 months 2 weeks 6 days 15 hours ago) and read 21015 times:

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

User currently onlineStitch From United States of America, joined Jul 2005, 30532 posts, RR: 84
Reply 6, posted (2 years 4 months 2 weeks 6 days 6 hours ago) and read 20866 times:
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Quoting CX Flyboy (Reply 5):
How about cargo in terms of not payload but container carrying capability?

The 777-9 would add another 4-6 LD3 positions (so 48-50 compared to 44 on the A350-1000), but they A350-1000 should have more available for revenue cargo due to a lower passenger baggage count.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19371 posts, RR: 58
Reply 7, posted (2 years 4 months 2 weeks 5 days 23 hours ago) and read 20734 times:

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.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 8, posted (2 years 4 months 2 weeks 5 days 22 hours ago) and read 20711 times:

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.


User currently offlinezeke From Hong Kong, joined Dec 2006, 8861 posts, RR: 75
Reply 9, posted (2 years 4 months 2 weeks 5 days 21 hours ago) and read 20691 times:

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
User currently onlineStitch From United States of America, joined Jul 2005, 30532 posts, RR: 84
Reply 10, posted (2 years 4 months 2 weeks 5 days 21 hours ago) and read 20687 times:
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Which is why I think if a 2m stretch is all Boeing can get, they shouldn't bother.

User currently offlineDocLightning From United States of America, joined Nov 2005, 19371 posts, RR: 58
Reply 11, posted (2 years 4 months 2 weeks 5 days 17 hours ago) and read 20649 times:

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.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 12, posted (2 years 4 months 2 weeks 5 days 14 hours ago) and read 20607 times:

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.


User currently offlineDocLightning From United States of America, joined Nov 2005, 19371 posts, RR: 58
Reply 13, posted (2 years 4 months 2 weeks 5 days 3 hours ago) and read 20479 times:

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?


User currently offlinemffoda From United States of America, joined Apr 2010, 1051 posts, RR: 0
Reply 14, posted (2 years 2 months 3 weeks 4 hours ago) and read 19146 times:

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.



harder than woodpecker lips...
User currently offlinenomadd22 From United States of America, joined Feb 2008, 1828 posts, RR: 0
Reply 15, posted (2 years 2 months 3 weeks 3 hours ago) and read 19110 times:

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


Andy Goetsch
User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 16, posted (2 years 2 months 2 weeks 6 days 16 hours ago) and read 18904 times:

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.


User currently offlinepanais From Cyprus, joined May 2008, 461 posts, RR: 0
Reply 17, posted (2 years 2 months 2 weeks 6 days 10 hours ago) and read 18845 times:

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.


User currently offlinenomadd22 From United States of America, joined Feb 2008, 1828 posts, RR: 0
Reply 18, posted (2 years 2 months 2 weeks 6 days 9 hours ago) and read 18807 times:

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.



Andy Goetsch
User currently onlineStitch From United States of America, joined Jul 2005, 30532 posts, RR: 84
Reply 19, posted (2 years 2 months 2 weeks 6 days 9 hours ago) and read 18814 times:
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Well an EK A350-1000 will have 317 seats (per EK), so the gap between it and a 777-9 will be not insubstantial.

User currently offlinepanais From Cyprus, joined May 2008, 461 posts, RR: 0
Reply 20, posted (2 years 2 months 2 weeks 6 days 2 hours ago) and read 18692 times:

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.


User currently offlineLAXDESI From United States of America, joined May 2005, 5086 posts, RR: 48
Reply 21, posted (2 years 2 months 2 weeks 6 days 1 hour ago) and read 18665 times:

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.


User currently onlineStitch From United States of America, joined Jul 2005, 30532 posts, RR: 84
Reply 22, posted (2 years 2 months 2 weeks 5 days 22 hours ago) and read 18611 times:
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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.


User currently offlinepanais From Cyprus, joined May 2008, 461 posts, RR: 0
Reply 23, posted (2 years 2 months 2 weeks 5 days 15 hours ago) and read 18522 times:

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.


User currently offlineCXB77L From Australia, joined Feb 2009, 2596 posts, RR: 5
Reply 24, posted (2 years 2 months 2 weeks 5 days 10 hours ago) and read 18469 times:
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CHAT OPERATOR

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
25 panais : Nobody is arguing that the 777-9X will not carry substantially more passengers. I do not think that you can get more than 3 economy rows and this mig
26 Stitch : 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 no
27 LAXDESI : 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...........
28 Post contains images nicoeddf : So, where is the usual disclaimer, that this many seats are obviously only helpful, if you can fill them...
29 Post contains images Stitch : 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 yo
30 zeke : 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 squabblin
31 rheinwaldner : 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 wil
32 Post contains images Stitch : 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 jus
33 zeke : "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 obt
34 Post contains images ferpe : Re seats etc, here a more useable measure on how the -1000 and -8X and -9X differ: Aircraft.............................A350-1000.......777-300ER.....
35 LAXDESI : 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
36 LAXDESI : 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
37 ferpe : 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 weig
38 LAXDESI : 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 b
39 ferpe : 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
40 LAXDESI : 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
41 Post contains images ferpe : 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 d
42 zeke : 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 add
43 OldAeroGuy : Are you sure the A350 fuselage only weighs 223 kg/m? Seems a bit light, since that would be about 12.5 lb/in.
44 zeke : 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 m
45 Post contains images LAXDESI : 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
46 OldAeroGuy : It also matches the 9 A/B (A350) vs 10 A/B (777X) Y class seating.
47 Roseflyer : 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 fus
48 zeke : 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
49 Max Q : 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 ?!
50 nomadd22 : I gather better aerodynamics means better lift and better acceleration, so you don't need the same power to weight ratio to cruise or get off the gro
51 Post contains links ferpe : The key is the new wing and especially it's 71m span, at the start some 75% of the drag is induced drag which is dependent on the span. Look in the t
52 zeke : Wrong.
53 OldAeroGuy : When you include a konstant to account for span efficiency, which Ferpe does, he is correct. Do you have a better explantion for the factors that inf
54 Roseflyer : That is where the factor for various wing designs comes in. In reality induced drag depends on airspeed, aspect ratio and wing area. Ferpe’s overal
55 ferpe : aspect ratio = span^2 / wingarea , this is why induced drag reduces to span, weight, dynamic pressure (more correct then airspeed) and your span effi
56 zeke : I take it you are referring to Oswald's efficiency factor ? If they were the ONLY factors that dictate induced drag, the aerodynamic design of wing w
57 OldAeroGuy : This is likely the result of finding the 1 g flight shape was different than the predicted deflections. Oswald is a little simple for the high lift r
58 zeke : Simple question, are the factors he listed the ONLY factors, yes or no ? And no, the press comments at the time of the twist chage said to improve ef
59 OldAeroGuy : Same thing, if the inflight twist had matched the design value (ie most efficient), there would be no need for a change. He was explaning why use of
60 rheinwaldner : This result seems not to be plausible, IMO. At least not if induced drag shall be responsible for the difference. Induced drag is Di = 2 * L^2 / (Rho
61 astuteman : Understanding the reduction in induced drag, I thought that the physical characteristics of wing loading and the sheer size of the area producing lif
62 ferpe : 1. You shall use the effective wingspan of both wings, ie including the induced drag mitigating effect of the wingtip devices, otherwise you will dis
63 ferpe : The start is the case were the induced drag is your real problem, look in the thread Boeing Vs. Airbus Wing Design Philosophies, there are some simul
64 OldAeroGuy : These parameters are of more interest for takeoff field length characteristics. You can have two wings with the same wing loading (W/S) and span effi
65 sweair : Can you guys do a run on the 779-X vs 748i? It would be interesting to compare these two frames. In 2014 LH expects to get a lighter frame and GE has
66 Max Q : I am only a Pilot, not an engineer but it still doesn't add up to me. Regardless of what this new structure is made of or how much longer the wing is
67 LAXDESI : Roughly speaking, for a 6,000nm trip: B748 burns about 14,000 more gallons of fuel($45,000) than B777-9X. B748 can carry up to 20,000 lbs. more cargo
68 Post contains links ferpe : The model I have built is a simplified model of preliminary analysis tool described here: http://adg.stanford.edu/aa241/AircraftDesign.html. This in
69 rheinwaldner : Ok, thanks. So the Di will favour the A351 even more. I did not put in values. Just by looking at the formula, one can see that the 778X has more ind
70 astuteman : you will have to explain to me how the 777-8X ends up with 20% less parasitic drag with wings that have 10% more surface area than the A350-1000, and
71 ferpe : This is what I did in the table below, sorry about the dots, it is an Excel delimiter for 1000 in European writing, my fault. The table should have b
72 ferpe : It should not, if the wingarea is 10% larger then the wetted area is 20% larger and the 70m2 diff in fuselage area does not compensate that. The pres
73 sweair : Maybe a combi model of the 748i is the best compromise, as a pure passenger hauler the 779-X will be better. The 748i is not the same NG as the 777 wi
74 JoeCanuck : Good work folks. The back and forth is providing interesting insight into the theoretical future of the 777...especially considering those crunching t
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