PhilSquares
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A350XWB Weight Issues

Wed May 13, 2009 1:56 pm

Looks like Airbus is having some weight issues with the 350XWB.

http://www.flightglobal.com/articles...hrust-values-following-weight.html
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Stitch
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RE: A350XWB Weight Issues

Wed May 13, 2009 5:26 pm

We've known for almost a year that the A350XWB was heavier then originally planned when they announced the 2t MWE overage and 3t MTOW increase to cover it last June. In May of that yeay, Germany’s Handelsblatt newspaper claimed in a report that the MWE overage was in excess of 8t which Airbus denied and subsequently reported the 2t/3t numbers. However, they did not announce a thrust increase would be required to compensate until now. The original thrust reductions were announced in September 2007.

This brings the A350-800XWB back to the original thrust spec, though the A350-900XWB remains 3000lbs less and the A350-1000XWB remains 2000lbs less then the original specification Airbus announced at Paris 2007.

It appears that the claimed superior wing design (which itself was extended close to 1m from the Paris 2007 specs) of the A350-800XWB could not alone compensate for the MWE/TOW increases and Airbus needed to increase the thrust back to 75,000lbs, matching the 245t MTOW 787-9.

Which I personally find mildly intriguing because many have put forward the opinion that the A350-800XWB is "overwinged" for it's size and should therefore have the best aerodynamic performance of the family, yet Airbus could not lower the thrust ratings for it's engines...
 
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jambrain
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RE: A350XWB Weight Issues

Thu May 14, 2009 6:44 pm



Quoting Stitch (Reply 1):
Airbus could not lower the thrust ratings for it's engines

I'm sure RR would say as the TrentXWB for A358 and A359 are identical except for rating plug, it's not exactly the biggest deal in engineering history to add thrust to 800 vesion!
Jambrain
 
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Stitch
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RE: A350XWB Weight Issues

Fri May 15, 2009 2:17 pm



Quoting Jambrain (Reply 2):
I'm sure RR would say as the TrentXWB for A358 and A359 are identical except for rating plug, it's not exactly the biggest deal in engineering history to add thrust to 800 vesion!

I understand it's not a problem for Rolls.

I'm just interested in why, while the larger and heavier A350-900XWB and A350-1000XWB don't need as much thrust as Airbus originally planned for, the A350-800XWB does, and it's supposed to be the most aerodynamically efficient model of the family because the wing is said to be larger then it needs to be for the plane, so it generates additional lift which should reduce the thrust needs.
 
osiris30
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RE: A350XWB Weight Issues

Fri May 15, 2009 2:29 pm

Quoting Stitch (Reply 1):
However, they did not announce a thrust increase would be required to compensate until now.

Not true. This is the second thrust bump on the 350XWB. From the article:

Quote:
This is the second thrust adjustment for the A350. In 2007, Airbus revealed reductions in nominal thrust values of between 1,000lb and 4,000lb for each variant.


(edit) Forget I said anything.. Misread what Stitch said and somehow managed to confuse myself in the process. Thanks for the correction below (/edit)

[Edited 2009-05-15 07:41:15]
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
A342
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RE: A350XWB Weight Issues

Fri May 15, 2009 2:35 pm



Quoting Osiris30 (Reply 4):
Not true. This is the second thrust bump on the 350XWB. From the article:

Read closely. They previously REDUCED the thrust targets.
Exceptions confirm the rule.
 
astuteman
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RE: A350XWB Weight Issues

Fri May 15, 2009 4:17 pm



Quoting PhilSquares (Thread starter):
Looks like Airbus is having some weight issues with the 350XWB.

Thanks for the link.

The thrust bump is news.

The weight "issues" are very old news, and not "issues".
Airbus responded to a 2.2t growth on OEW with a 3t growth in MTOW and 5t growth in MZFW, to resolve the "issue".

Quoting Osiris30 (Reply 4):
This is the second thrust bump on the 350XWB

These thrust levels are still either below or the same as the thrust levels originally declared 2 years ago.

Rgds
 
nomadd22
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RE: A350XWB Weight Issues

Fri May 15, 2009 4:31 pm

Can't we just copy and paste the last 6 years of A380/B787 comments with the names changed and save time?
Anon
 
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Pellegrine
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RE: A350XWB Weight Issues

Fri May 15, 2009 5:06 pm



Quoting Stitch (Reply 3):
I'm just interested in why, while the larger and heavier A350-900XWB and A350-1000XWB don't need as much thrust as Airbus originally planned for, the A350-800XWB does, and it's supposed to be the most aerodynamically efficient model of the family because the wing is said to be larger then it needs to be for the plane, so it generates additional lift which should reduce the thrust needs.

Possibly because it is supposed to have the highest range of the family.
oh boy, here we go!!!
 
osiris30
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RE: A350XWB Weight Issues

Fri May 15, 2009 7:13 pm



Quoting Astuteman (Reply 6):
These thrust levels are still either below or the same as the thrust levels originally declared 2 years ago.

See my edit comment... I was still half asleep responding and my brain took a hard right into 'moron mode'.
I don't care what you think of my opinion. It's my opinion, so have a nice day :)
 
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Stitch
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RE: A350XWB Weight Issues

Fri May 15, 2009 10:29 pm



Quoting Pellegrine (Reply 8):
Possibly because it is supposed to have the highest range of the family.

Well the A350-800XWB's MTOW is now 3t higher then the 787-9, so that it only needs the same thrust might be due to the better aerodynamics of the wing.

With identical wings on the 777-200 and 777-300, the 777-300 needed 20,000 pounds more thrust to support 115,000 pounds more TOW, which is a ratio of 5.75:1.

With identical wings on the A350-800XWB and the A350-900XWB, the A350-900XWB needs 9,000 pounds more thrust to support 44,100 pounds more TOW for a ratio of 4.9:1. And for the A350-1000XWB, it needs 19,000 pounds more thrust to support 110,300 pounds more TOW for a ratio of 5.8:1.
 
Caryjack
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RE: A350XWB Weight Issues

Sat May 16, 2009 12:13 am



Quoting Nomadd22 (Reply 7):
Can't we just copy and paste the last 6 years of A380/B787 comments with the names changed and save time?

What?? and miss all this???

Quoting Osiris30 (Reply 4):
Forget I said anything.. Misread what Stitch said and somehow managed to confuse myself in the process.



Quoting Astuteman (Reply 6):
The weight "issues" are very old news, and not "issues".



Quoting Osiris30 (Reply 9):
I was still half asleep responding and my brain took a hard right into 'moron mode'.

Please pass the popcorn.  laughing 
Thanks,
Cary

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