User avatar
clickhappy
Posts: 9042
Joined: Thu Sep 13, 2001 12:10 pm

A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:18 am

Was just having a look at the link provide in another thread, where some numbers are provided for the A350XWB family.

Something does not make sense to me. But I am no engineer, so please feel free to set me straight.

The number supplied by Flight International show that the A350-800 has a range max range of 15,730km, with a max fuel capacity of 150,000 litres.

The numbers for the A350-1000 show it to have a range of 15,360km, with a max fuel capacity of 150,000 litres.

The A350-1000 is a much larger plane than the A358, 40 feet longer, with a capacity of 80 more pax than the A350-800. It also has much more powerful engines.

So, how is it that the A350-1000 range will be almost the same as the A350-800, yet it is a much bigger airframe?
 
User avatar
N328KF
Posts: 5810
Joined: Tue May 25, 2004 3:50 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:24 am

Quoting Clickhappy (Thread starter):

So, how is it that the A350-1000 range will be almost the same as the A350-800, yet it is a much bigger airframe?

Bigger belly == more belly tanks.
When they call the roll in the Senate, the Senators do not know whether to answer 'Present' or 'Not guilty.' -Theodore Roosevelt
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:24 am

Quoting Clickhappy (Thread starter):
So, how is it that the A350-1000 range will be almost the same as the A350-800, yet it is a much bigger airframe?

A good reason would be that the -800 engines are derates from the -900 and -1000 versions, and therefore less efficient than the -900 and -1000 series engines. This would make for a lower decrease in range for a larger airframe as the higher thrust engines gain efficiency on the scale. Theres a reduction but not as big as it should be on an 'all things equal' scale because all things are not equal.

[Edited 2006-12-11 20:34:37]
 
User avatar
clickhappy
Posts: 9042
Joined: Thu Sep 13, 2001 12:10 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:25 am

The numbers provided show the max fuel being the same for both models, 150,000 litres.

I would assume you mean that additional fuel can be carried in belly tanks?

Perhaps the specs are wrong?
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:26 am

Quoting N328KF (Reply 1):
Bigger belly == more belly tanks.

But Clickhappy quotes the two max fuel capacities as the same.
 
ikramerica
Posts: 13807
Joined: Mon May 23, 2005 9:33 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:27 am

Or that the 358 is MTOW limited, not fuel limited.
Of all the things to worry about... the Wookie has no pants.
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:27 am

Quoting Clickhappy (Reply 3):
Perhaps the specs are wrong?

Thats the most obvious. We shall see over the next year or two when the specifications and numbers are refined.
 
User avatar
clickhappy
Posts: 9042
Joined: Thu Sep 13, 2001 12:10 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:28 am

Thank you for the replys.

Here is the link if anyone wants to see the numbers.

http://www.flightglobal.com/Articles...s's+A350+vision+takes+shape+.html
 
baron95
Posts: 1106
Joined: Thu May 25, 2006 10:19 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:35 am

Here is what I think the OP is referring to (from the same FI article above).

I think the key is that it is shown as "Design Range". To me that is a fuzzy term that can mean almost anything. My take is that they just adjust the payload down on the larger models to meet the similar ranges - or some other vodoo like that. I have serious doubt that they can get the -1000 off the groun (except maybe with 12,000feet+ runways) with just 95Klbs of thrust.

Big version: Width: 450 Height: 337 File size: 41kb
A350XWB Family Specifications
Killer Fleet: E190, 737-900ER, 777-300ER
 
ikramerica
Posts: 13807
Joined: Mon May 23, 2005 9:33 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:43 am

Look, it's not as weird as it seams.

The fuel capacity of the 787-3 is the same as the 787-8, yet the 787-8 range is 5000nm greater. Just because a fuel tank can hold a certain amount doesn't mean it can lift all that fuel and a full payload at the same time.
Of all the things to worry about... the Wookie has no pants.
 
astuteman
Posts: 6406
Joined: Mon Jan 24, 2005 7:50 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:45 am

Quoting Baron95 (Reply 8):
I have serious doubt that they can get the -1000 off the groun (except maybe with 12,000feet+ runways) with just 95Klbs of thrust.

Isn't 295t (or 650 000lb) remarkably similar to the 772ER, which has similar thrust?

Quoting Ikramerica (Reply 5):
Or that the 358 is MTOW limited, not fuel limited.

It may possibly be a typo, but it might also be possible that Ikramerica's comment may apply. In practice, the A358 may never actually carry 150k litres, except, maybe on ferry flights, whereas the -1000 might routinely carry 150k litres with high payloads.
(you'd still expect it to have a bigger capacity, though, wouldn't you? )

Regards
 
baron95
Posts: 1106
Joined: Thu May 25, 2006 10:19 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 4:59 am

Quoting Astuteman (Reply 10):
Isn't 295t (or 650 000lb) remarkably similar to the 772ER, which has similar thrust?

True enough.

But I was referring to Airbus claims of a 3-class config of 350 passengers (like an 77W) and 8,300nm range (like an 77L). I don't believe that a plane with that capability (as many pssengers and greater range than a 77W) can weigh (MTOW) as only as much as 772ER. Therefore, I don't think it can take-off with the same thrust, except if the runway requirements are out of sight. Just my 2c - what do I know - they design and build airplanes for a living.
Killer Fleet: E190, 737-900ER, 777-300ER
 
Hamlet69
Posts: 2481
Joined: Thu Mar 09, 2000 2:45 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:02 am

What I don't get is how the A350-800 is roughly 5 feet longer than the 787-9, but will carry 10 fewer LD-3's!!

Anyone?

Hamlet69  profile 
Honor the warriors, not the war.
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:02 am

Quoting Astuteman (Reply 10):
Isn't 295t (or 650 000lb) remarkably similar to the 772ER, which has similar thrust?

A350-1000 - 95,000lb thrust
777-200ER - 90,000 to 93,000lb thrust

A350-1000 - 295mt MTOW
777-200ER - 297mt MTOW

A350-1000 - 15,360km
777-200ER - 14,316km

Good spot there Astuteman, it would seem you are correct.
(data above taken from the chart above and http://www.boeing.com/commercial/777family/pf/pf_200product.html )
 
User avatar
Stitch
Posts: 23453
Joined: Wed Jul 06, 2005 4:26 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:06 am

Quoting Baron95 (Reply 11):
I don't believe that a plane with that capability (as many pssengers and greater range than a 77W) can weigh (MTOW) as only as much as 772ER.

Depends on how much weight-savings Airbus' construction materials provide.
 
EI321
Posts: 4788
Joined: Tue Jul 07, 2009 4:43 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:11 am

Hamlet, maybe there is less room in the hold due to crew rest area, lavs, etc?
 
WINGS
Posts: 2312
Joined: Tue May 31, 2005 1:36 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:13 am

Quoting Hamlet69 (Reply 12):
What I don't get is how the A350-800 is roughly 5 feet longer than the 787-9, but will carry 10 fewer LD-3's!!

Anyone?

Could it be that the A350 will use underfloor galleys,toilets, crew rest compartment?

Regards,
Wings
Aviation Is A Passion.
 
baron95
Posts: 1106
Joined: Thu May 25, 2006 10:19 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:14 am

Quoting RichardPrice (Reply 13):
A350-1000 - 95,000lb thrust
777-200ER - 90,000 to 93,000lb thrust

A350-1000 - 295mt MTOW
777-200ER - 297mt MTOW

A350-1000 - 15,360km
777-200ER - 14,316km

Lets add:
A350-1000 - 350 passengers 3-class config
777-200ER - 301 passengers 3-class config

So Airbus can add 49 passangers (20%), oven 1,000 KM of range (7.5%) and keep have a lower MTOW? I'm not saying it is impossible, but I have a hard time believing they'll get there.
Killer Fleet: E190, 737-900ER, 777-300ER
 
beech19
Posts: 887
Joined: Fri Jul 21, 2006 11:30 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:26 am

Quoting Ikramerica (Reply 9):
Look, it's not as weird as it seams.

The fuel capacity of the 787-3 is the same as the 787-8, yet the 787-8 range is 5000nm greater. Just because a fuel tank can hold a certain amount doesn't mean it can lift all that fuel and a full payload at the same time.

You just compared two different situations though. True they ARE the same size but they -3 is designed to have a lower MTOW because it carries much less fuel (and less wing for that matter). The A358 and A3510 are 40ft difference in size and i would expect the -1000 to have a much higher MTOW, if not the range would be drastically lower based on the same fuel.

I'm thinking its either a limitation by weight or the spec was screwed up. We shall wait and see...
KPAE via KBVY
 
A342
Posts: 4017
Joined: Sun Jul 31, 2005 11:05 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:27 am

Quoting Ikramerica (Reply 9):
Look, it's not as weird as it seams.

The fuel capacity of the 787-3 is the same as the 787-8, yet the 787-8 range is 5000nm greater. Just because a fuel tank can hold a certain amount doesn't mean it can lift all that fuel and a full payload at the same time.

Bingo ! It's the same thing with the A332 and A343. Both have about the same fuel capacity, yet the A332 is significantly smaller, lifts less payload and has a lower range.

A manufacturer might chose to give an aircraft excess fuel capacity so that just one version of the wing/tank has to be produced
Exceptions confirm the rule.
 
futurecaptain
Posts: 1918
Joined: Sat Sep 09, 2006 1:54 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:56 am

From the released design specs...

The A350-8 can fly 15,730 km on 150,000 L of fuel.
So, 9.53 L per Km

The 787-9 can fly 16,300 km on 138,700 L of fuel
So, 8.51 L per Km

At the paper specs for the airplanes the 787 comes out a full 10.7% more efficient than the A350.

Now I realize both I am comparing manufacurers numbers for both birds and neither are in service, but it seems Airbus better have some great technology in the A350 to make up for this.
AirSO. ASpaceO. ASOnline. ASO.com ASO. ASO. ASO. ASO. ASO.
 
Ruscoe
Posts: 1586
Joined: Sun Aug 22, 1999 5:41 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:59 am

Quoting Baron95 (Reply 17):
Lets add:
A350-1000 - 350 passengers 3-class config
777-200ER - 301 passengers 3-class config

This is at 9 abreast for the 350 & 772ER, but the 777 can go 10 abreast and the 350 can't.
Airlines being what they are, and competition being what it is, I think the extra width of the 350, without allowing an extra row of seats, will be a disadvantage eventually.

Seems to me that Airbus have set the width to compete with 787 and weights to compete with 777. I can see problems ahead.

Also $15.5 billion should buy you more than CFRP coverd aluminium.

Ruscoe
 
BoomBoom
Posts: 2459
Joined: Fri Nov 04, 2005 2:26 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:01 am

Quoting WINGS (Reply 16):
Could it be that the A350 will use underfloor galleys,toilets, crew rest compartment?

Won't that limit cargo? I thought the new fuselage cross section will allow for a crown area crew rest.

[Edited 2006-12-11 22:27:18]
Our eyes are open, our eyes are open--wide, wide, wide...
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:03 am

Quoting Futurecaptain (Reply 23):

The A350-8 can fly 15,730 km on 150,000 L of fuel.
So, 9.53 L per Km

The 787-9 can fly 16,300 km on 138,700 L of fuel
So, 8.51 L per Km

At the paper specs for the airplanes the 787 comes out a full 10.7% more efficient than the A350.

Maximum fuel capacity does not equal 'wot will be used for maximum range' - as stated above, the aircraft may be MTOW limited (as is some of the A320 family aircraft due to using the same fuel tanks). Technically thats the capacity, but it wouldnt be usable.
 
RichardPrice
Posts: 4474
Joined: Sat Apr 23, 2005 5:12 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:04 am

Quoting BoomBoom (Reply 25):
Won't that limit cargo?

Thats already been pointed out.
 
jonathan-l
Posts: 394
Joined: Thu Mar 28, 2002 4:20 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:07 am

Quoting Futurecaptain (Reply 23):
From the released design specs...

The A350-8 can fly 15,730 km on 150,000 L of fuel.
So, 9.53 L per Km

The 787-9 can fly 16,300 km on 138,700 L of fuel
So, 8.51 L per Km

At the paper specs for the airplanes the 787 comes out a full 10.7% more efficient than the A350.

The ranges you quote are for max pax.
The fuel capacities you quote are the max fuel capacity.
They do not occur simultaneously on the payload range.
 
EI321
Posts: 4788
Joined: Tue Jul 07, 2009 4:43 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:16 am

edit: double post ..........................

[Edited 2006-12-11 22:19:19]
 
EI321
Posts: 4788
Joined: Tue Jul 07, 2009 4:43 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:17 am

Quoting Baron95 (Reply 17):
Quoting RichardPrice (Reply 13):
A350-1000 - 95,000lb thrust
777-200ER - 90,000 to 93,000lb thrust

A350-1000 - 295mt MTOW
777-200ER - 297mt MTOW

A350-1000 - 15,360km
777-200ER - 14,316km

Lets add:
A350-1000 - 350 passengers 3-class config
777-200ER - 301 passengers 3-class config

So Airbus can add 49 passangers (20%), oven 1,000 KM of range (7.5%) and keep have a lower MTOW? I'm not saying it is impossible, but I have a hard time believing they'll get there.

Its important to take into account that the A350-1000 will weigh less per passenger than the 772ER, so despite having an (approx) 15% higher capacity than the 772ER, the need for a higher MTOW might be canceled out by the lower OEW & fuel consumption per passenger, thus the MTOW ends up being very similar for both.

Quoting RichardPrice (Reply 22):
Quoting A342 (Reply 21):
Uh, what do you mean ?


Dont feed the troll, just suggest delete

Its sarcasm obviously!
 
futurecaptain
Posts: 1918
Joined: Sat Sep 09, 2006 1:54 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:17 am

Quoting RichardPrice (Reply 26):



Quoting Jonathan-l (Reply 28):


Granted, we have to see how both planes perform in service before making sweping generalizations as I have. But it is still fun to think about.  yes   spin 
AirSO. ASpaceO. ASOnline. ASO.com ASO. ASO. ASO. ASO. ASO.
 
gigneil
Posts: 14133
Joined: Fri Nov 08, 2002 10:25 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:17 am

Quoting Baron95 (Reply 17):
I'm not saying it is impossible, but I have a hard time believing they'll get there.

The plane itself is significantly lighter and will consume some 15 to 20% less fuel.

NS
 
atmx2000
Posts: 4301
Joined: Wed Oct 13, 2004 4:24 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:19 am

Quoting Hamlet69 (Reply 12):
What I don't get is how the A350-800 is roughly 5 feet longer than the 787-9, but will carry 10 fewer LD-3's!!

I don't the A350 is tall enough to support an overhead crew rest, so they probably use under deck space. That will take up a fair amount of space.
ConcordeBoy is a twin supremacist!! He supports quadicide!!
 
User avatar
Devilfish
Posts: 5367
Joined: Tue Jan 24, 2006 7:52 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:24 am

Here's the latest FI report on the Trent XWB engine with some details.....

http://www.flightglobal.com/Articles...eleases+new+data+on+Trent+XWB.html

Quote:
"For the original A350, R-R offered the Trent 1700, developed from the Trent 1000 with a 2.86m fan and a thrust range up to the mid-70,000lb (310kN) level.

In contrast, R-R plans to certificate the XWB engine at 95,000lb thrust, but says it will enter service at a rating of 87,000lb on the initial A350 XWB-900 in 2013.

The engine will later be derated to 75,000lb thrust for the smaller, lighter XWB-800 and operated at 95,000lb for the -1000."
"Everyone is entitled to my opinion." - Garfield
 
DIA
Posts: 3053
Joined: Sun Jan 28, 2001 2:24 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:27 am

In reply #8, the table shows a note at the bottom stating that the A350-900R has an EIS of mid-2016. What is an A350-900R?
Ding! You are now free to keep supporting Frontier.
 
User avatar
clickhappy
Posts: 9042
Joined: Thu Sep 13, 2001 12:10 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:30 am

The plane itself is significantly lighter and will consume some 15 to 20% less fuel.

30%, if you believe the hype.
 
User avatar
Stitch
Posts: 23453
Joined: Wed Jul 06, 2005 4:26 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:00 am

Quoting DIA (Reply 35):
In reply #8, the table shows a note at the bottom stating that the A350-900R has an EIS of mid-2016. What is an A350-900R?

"R" is an Airbus designation for a long-range aircraft.

Essentially the A350's answer to the 777-200LR and A340-500.
 
beech19
Posts: 887
Joined: Fri Jul 21, 2006 11:30 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:02 am

Quoting DIA (Reply 35):
In reply #8, the table shows a note at the bottom stating that the A350-900R has an EIS of mid-2016. What is an A350-900R?

One of the many hypotheticals in the A350 project... supposedly a -900 super duper long freaking range. We'll see...
KPAE via KBVY
 
EI321
Posts: 4788
Joined: Tue Jul 07, 2009 4:43 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:10 am

Quoting Beech19 (Reply 38):
One of the many hypotheticals in the A350 project... supposedly a -900 super duper long freaking range. We'll see...

Both airbus and boeing already have LR planes in service already, why cant it be done with future models?
 
astuteman
Posts: 6406
Joined: Mon Jan 24, 2005 7:50 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:15 am

Quoting Baron95 (Reply 17):
So Airbus can add 49 passangers (20%), oven 1,000 KM of range (7.5%) and keep have a lower MTOW? I'm not saying it is impossible, but I have a hard time believing they'll get there.

FWIW, I think there's a "virtuous" circle made possible by the improvements in engine SFC, and the improved structural weight combined, provided you know they're there at the start of design.

e.g. if you know your engine is say 10% more efficient, you can design your structure to carry less fuel from the start, which means a lower MTOW, which means lighter and smaller wings, which means lower MTOW, which means less fuel, which means a lower MTOW.......... (you see where I'm going?....)

FWIW, I think that it is this phenomenon that provides the 787 with such startling capability.
And I suspect if you compare the A350 specs with the 787, they're much more representative than if you compare with the 772.

It's also the reason IMO that a clean sheet will always beat a derivative, all other things being equal (and why the 787 beat the orignal A350..).

It's also why I don't believe the 777 can be evolved into a 1 for 1 match for the A350 (ultimately).
To match and beat the A350, Boeing will either need a bigger 787 (-10, or -11), or a Y3.
In this respect I believe Zvezda is correct.

Like you, I can't (and won't) profess to be an airframe designer - it just seems like a logical argument to me....

Feel free to blast away....  Smile

Regards
 
prebennorholm
Posts: 6443
Joined: Tue Mar 21, 2000 6:25 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:33 am

Quoting WINGS (Reply 16):
Quoting Hamlet69 (Reply 12):
What I don't get is how the A350-800 is roughly 5 feet longer than the 787-9, but will carry 10 fewer LD-3's!!

Anyone?

Could it be that the A350 will use underfloor galleys,toilets, crew rest compartment?

We are here assuming figurative and airline specific configurations. Configurations which may, or may not ever exist in reality.

WINGS is likely to be correct. On ultra long range planes there will be a tendency to put as much secondary facilities as possible under the floor. The reasons are:

- to maximize space for the (sleeping) pax.
- ultra long range cargo flight is not economical.

Most cargo is not in such a hurry that it cannot take a fuel stop on an 8,000 nm sector.

If we assume an 8,000 nm cargo flight, then it will cost a lot of fuel over the first 4,000 nm just to carry the fuel needed for the last 4,000 nm.

Alternatively, a lot of fuel will be saved by not carrying all that fuel, but make a fuel stop. But even more important, a lot more cargo can be carried instead of carrying all that fuel.

Therefore we won't see much cargo lifted of ultra long distance flights.

Passengers on the other hand like not to be disturbed in their sleep in the middle of a long flight.

But maybe we will see A358s one day with much more cargo space, on deck secondary facilities and a slightly smaller pax capacity. And, when the cargo capability is utilizes, then a somewhat reduced range.

If what the airline needs is a 6,000 nm plane with a 250 pax and substantial cargo lifting capability, then why not call it an A358? Properly configured, of course.
Always keep your number of landings equal to your number of take-offs
 
atmx2000
Posts: 4301
Joined: Wed Oct 13, 2004 4:24 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:44 am

Quoting Astuteman (Reply 40):
FWIW, I think there's a "virtuous" circle made possible by the improvements in engine SFC, and the improved structural weight combined, provided you know they're there at the start of design.

e.g. if you know your engine is say 10% more efficient, you can design your structure to carry less fuel from the start, which means a lower MTOW, which means lighter and smaller wings, which means lower MTOW, which means less fuel, which means a lower MTOW.......... (you see where I'm going?....)

I have noted this before. If you reduce fuel burn significantly, you need far less fuel to carry the additional fuel required for long range travel. This boosts range significantly. This maybe what Airbus thinks they will get away with on the -1000, but as Widebodyphotog has noted, Airbus is not known for structurally efficient airframes.

Quoting Astuteman (Reply 40):
It's also why I don't believe the 777 can be evolved into a 1 for 1 match for the A350 (ultimately).
To match and beat the A350, Boeing will either need a bigger 787 (-10, or -11), or a Y3.
In this respect I believe Zvezda is correct.

I agree that an upgraded 777 won't be competitive if Airbus can actually build a A350-1000 with similar capacity to the -300ER with greater range that uses 95000 lbs engines. It's just that one has the question Airbus's ability to deliver an entire family of optimized aircraft models.

What might be more problematic is that the 350-400 pax market might be saturated at that point. The A359 makes plenty of sense as it is clear that the replacement market for 300 pax aircraft like the MD11/A333/A343/772A/772ERs will be taking off at that point.

Boeing likely will be better served to bring out Y3 closer to the end of the decade, to start the replacement run for the 773ERs and then move to the replacement market for 748s a few years later.
ConcordeBoy is a twin supremacist!! He supports quadicide!!
 
User avatar
Revelation
Posts: 14474
Joined: Wed Feb 09, 2005 9:37 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 7:55 am

Quoting Beech19 (Reply 18):
The A358 and A3510 are 40ft difference in size and i would expect the -1000 to have a much higher MTOW, if not the range would be drastically lower based on the same fuel.

I'm thinking its either a limitation by weight or the spec was screwed up. We shall wait and see...

Maybe the A358 was done in CATIA v3 and the A359 was done in CATIA v4?  biggrin 
Inspiration, move me brightly! Light the song with sense and color.
Hold away despair, more than this I will not ask.
Faced with mysteries dark and vast, statements just seem vain at last.
Some rise, some fall, some climb, to get to Terrapin!
 
beech19
Posts: 887
Joined: Fri Jul 21, 2006 11:30 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 8:11 am

Quoting EI321 (Reply 36):
Both airbus and boeing already have LR planes in service already, why cant it be done with future models?

I didn't say it couldn't be done... i just said its a hypotetical. We shall see if the A350 ever meets the tarmac... i'm still not a beleiver.  duck 
KPAE via KBVY
 
pygmalion
Posts: 818
Joined: Thu Jun 29, 2006 12:47 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 8:21 am

I still think that the preferred Boeing plan for the Y3 would be to target the Y3-8 at the 350 pax space, the Y3-9 at 400 and the Y3-10 at 450. The Y3-8, -9, -10 would replace the 773 and up to the 748 and compete with the A359 and A3510. The 787-10 would compete with the A358. So after Airbus reaches firm design sign off on the A359 (first to launch) Boeing responds with the Y3-8 and goes from there. Airbus most likely would need another aircraft to fill in the family hole between the A350 and the A380
 
atmx2000
Posts: 4301
Joined: Wed Oct 13, 2004 4:24 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 8:39 am

Quoting Pygmalion (Reply 42):
I still think that the preferred Boeing plan for the Y3 would be to target the Y3-8 at the 350 pax space, the Y3-9 at 400 and the Y3-10 at 450. The Y3-8, -9, -10 would replace the 773 and up to the 748 and compete with the A359 and A3510. The 787-10 would compete with the A358. So after Airbus reaches firm design sign off on the A359 (first to launch) Boeing responds with the Y3-8 and goes from there. Airbus most likely would need another aircraft to fill in the family hole between the A350 and the A380

The 787-10 is the A359 competitor.

Anyway, I think a Y3 will start closer to 370 seats than 350. The 787-10 will likely seat between 310-330 seats with 9Y seating. The seating increments between family members for the Y3 probably should be closer to 60-70 seats, otherwise the models will be too close in size. With that separation, a 3 member family will extend to 500 seats.
ConcordeBoy is a twin supremacist!! He supports quadicide!!
 
pygmalion
Posts: 818
Joined: Thu Jun 29, 2006 12:47 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 8:46 am

I could be off on the A350-XXX... I am so confused by the A350 numbering system  confused  spin  ...

But I think we are pretty much on the same page. At least I can't argue with your numbers ATMX2K
 
Hamlet69
Posts: 2481
Joined: Thu Mar 09, 2000 2:45 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:08 pm

Quoting Prebennorholm (Reply 38):
WINGS is likely to be correct. On ultra long range planes there will be a tendency to put as much secondary facilities as possible under the floor. The reasons are:

- to maximize space for the (sleeping) pax.
- ultra long range cargo flight is not economical.

While I certainly understand and agree with the point you are trying to make, I don't believe that was what the chart was showing. On any manufacturer's detail charts I've ever seen, they usually list a max. value. In other words, max pax, max range, max fuel, etc. In the real world, we know that none of these "max" values are ever seen together, as any route is a balance between them.

Once again looking at that chart provided by Airbus for FT, we see this holds true (MTOW, max fuel volume, max range, etc.). Therefore one must come to the logical conclusion that when "LD-3 containers" is listed, the amount noted is how much volume capacity is involved, not payload capacity. In other words, if an airline wants the A350-800 to fly 250 pax. 6,500nm in order to carry more cargo, that cargo will have to be more dense, as the airline can not suddenly fit in an extra few LD-3's.

Once again, that is my reading of the chart provided. Note that it is also early in the development process, so all these numbers are of course subject to change.

Regards,

Hamlet69  profile 
Honor the warriors, not the war.
 
ap305
Posts: 970
Joined: Mon Jan 03, 2000 4:03 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 5:52 pm

It appears, from the figures, that the a350-800xwb pays the price of over engineering for a stretch(-1000). The 787-9 carries more passengers with a greater range at the same mtow. On the other hand if Boeing stretches the growth envelope of the 787 this advantage may swing the other way.Interesting that Airbus has not revealed the empty weight- maybe a case of once bitten twice shy?.

[Edited 2006-12-12 09:55:46]
 
SailorOrion
Posts: 1959
Joined: Tue Feb 06, 2001 5:56 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 6:13 pm

Just to shed some light into the darkness, I've been crunching some numbers.

When using some first-order approximation, I get the following data:

I've started out with a 77W baseline aircraft, with specs taken from Boeing.
I have a takeoff mass of 345,000kg, an empty mass of 167,829kg and 69,853 kg worth of payload. This buys me a range of some 5500nm. Please note that absolute figures are of no interest in this observation.

Now lets assume we cut SFC to 90% (i.e. going from 1.00 to 0.90), and look at three options.
Option 1: We keep the masses and see that the range goes up by 11.1%.
Option 2: We want to keep the range, so the amout of fuel is reduced to 87.8% while MTOM is reduced to 96%.
Option 3: We want to keep range and MOTM, then payload goes up by 12.4%, the amount of fuel goes down to 92%.

On another model, we keep SFC untouched, but reduce OEW to 90%. (i.e. going from 1.00 to 0.90 again).
Option 1: Range goes up by 20.3% by increasing amount of fuel by 16%.
Option 2: Amout of fuel is reduced to 91.7%, MOTM drops to 93%.
Option 3: Payload up by 24.5%, amount of fuel unchanged.

Now lets combine both, we have SFC down to 90% and OEW down to 90%.
Option 1: Range up by 34%, amount of fuel up 16%.
Option 2: Amount of fuel reduced to 81%, MOTM down to 89%
Option 3: Payload up by 37%, amount of fuel down to 91%

How to interpret that data is up to you now  Smile

SailorOrion
 
EI321
Posts: 4788
Joined: Tue Jul 07, 2009 4:43 pm

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 9:10 pm

Quoting Ap305 (Reply 46):
The 787-9 carries more passengers with a greater range at the same mtow

Its a bigger aircraft.
 
ap305
Posts: 970
Joined: Mon Jan 03, 2000 4:03 am

RE: A358 Vs A351x Numbers Don't Make Any Sense

Tue Dec 12, 2006 9:55 pm

Quoting EI321 (Reply 48):

Its a bigger aircraft.

Yes but it weighs the same.

Popular Searches On Airliners.net

Top Photos of Last:   24 Hours  •  48 Hours  •  7 Days  •  30 Days  •  180 Days  •  365 Days  •  All Time

Military Aircraft Every type from fighters to helicopters from air forces around the globe

Classic Airliners Props and jets from the good old days

Flight Decks Views from inside the cockpit

Aircraft Cabins Passenger cabin shots showing seat arrangements as well as cargo aircraft interior

Cargo Aircraft Pictures of great freighter aircraft

Government Aircraft Aircraft flying government officials

Helicopters Our large helicopter section. Both military and civil versions

Blimps / Airships Everything from the Goodyear blimp to the Zeppelin

Night Photos Beautiful shots taken while the sun is below the horizon

Accidents Accident, incident and crash related photos

Air to Air Photos taken by airborne photographers of airborne aircraft

Special Paint Schemes Aircraft painted in beautiful and original liveries

Airport Overviews Airport overviews from the air or ground

Tails and Winglets Tail and Winglet closeups with beautiful airline logos