Discussion:
Barrel sections for the A350 ?
(too old to reply)
JF Mezei
2011-03-10 06:56:29 UTC
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Was lookinfg at the Airbus web site photo galleries to see if any
progress was being made on the A350.

Stumbled onto :

Loading Image...

The caption is:
##
Airbus starts production of first fuselage barrel for the A350 XWB (7
December 2010).
##




Since Airbus had announced that the 350 was going to have separate
panels (4 per cylinder section) that would be riveted to a composite
frame (as opposed to the 787's single piece fuselage barrels), I got
quite puzzled by the above image.

It shows a tape layup machine coating a rotating cylinder. The
cylinder's surface is smooth (as opposed to Boeing whih has the ridges
for the ribs that are to be part of the fuselage). However, the cylinder
is far from being round, or "aircraft" shaped.


Will they coat the whole barrel, and then slice pieces out, and then
bake them ?


Or is Airbus gotten a surprise with single piece barrel sections ?

Some time ago, they had a video of tape layup machine creating the
first fuselage panel, and it was on a table that looked flat.
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Uwe Klein
2011-03-10 09:12:33 UTC
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Post by JF Mezei
Was lookinfg at the Airbus web site photo galleries to see if any
progress was being made on the A350.
http://www.airbus.com/typo3temp/pics/65a96fd457.jpg
tailcone, see below.
Post by JF Mezei
##
Airbus starts production of first fuselage barrel for the A350 XWB (7
December 2010).
##
Since Airbus had announced that the 350 was going to have separate
panels (4 per cylinder section) that would be riveted to a composite
frame (as opposed to the 787's single piece fuselage barrels), I got
quite puzzled by the above image.
Produced and stuffed sections are barrel like ( just like
the assemblies for all Airbus types).
Boeing actually produces a one piece fuselage _skin_ with coccured
stringers, all other structure must be inserted and fastened:
titan frames, windows, doors, .... imho a cul de sac.
Post by JF Mezei
It shows a tape layup machine coating a rotating cylinder. The
cylinder's surface is smooth (as opposed to Boeing whih has the ridges
for the ribs that are to be part of the fuselage). However, the cylinder
is far from being round, or "aircraft" shaped.
That is the tailcone. Wound filament like the same part on the A380.
Post by JF Mezei
Will they coat the whole barrel, and then slice pieces out, and then
bake them ?
Or is Airbus gotten a surprise with single piece barrel sections ?
Tube segments make no sense for CFRP with an eye future progress
like cocured stringers, frames, doorframes and windowframes.
My guess is Airbus aims for "just joined segments" without all supportive
structure on the segments for the future.
Post by JF Mezei
Some time ago, they had a video of tape layup machine creating the
first fuselage panel, and it was on a table that looked flat.
The fuselage crown: a 1/4 section over the full length of that fuselage segment.

uwe
Post by JF Mezei
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Uwe Klein
2011-03-18 15:52:35 UTC
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Post by JF Mezei
Was lookinfg at the Airbus web site photo galleries to see if any
progress was being made on the A350.
OnTopic:
Quarter circumference side section forward fuselage:
http://www.flightglobal.com/articles/2011/03/18/354540/picture-airbus-german-plant-produces-largest-a350-panel.html
and some ancillary information on production progress
in various plants across Europe and the SU.

interesting:
the big cutouts are done ( passenger and belly door )
windows not.

I would have liked to see a picture of the inside too.



G!
uwe
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JF Mezei
2011-03-19 02:52:58 UTC
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Post by Uwe Klein
http://www.flightglobal.com/articles/2011/03/18/354540/picture-airbus-german-plant-produces-largest-a350-panel.html
The article mentions "starboard". is there any reason why the port side
would not be symmetrical (without cargo door) ?


Puzzling that they would have bothered painting the outside before
cutting out the windows.

How will they mount such a large spine-less panel to the frame ? Would
they use succion cups to lift/support it while it is mated to the
structure until there are enough rivets to keep it attached ?


Or does it have enough stiffness that they can grab it by the top and
lift it into position and it would retain its curved shape even if
grabbed by one side ?
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Uwe Klein
2011-03-19 09:52:46 UTC
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Post by JF Mezei
Post by Uwe Klein
http://www.flightglobal.com/articles/2011/03/18/354540/picture-airbus-german-plant-produces-largest-a350-panel.html
The article mentions "starboard". is there any reason why the port side
would not be symmetrical (without cargo door) ?
Puzzling that they would have bothered painting the outside before
cutting out the windows.
My guess is the female mould this piece was assembled and cured on
got a filled first layer of resin in layup. ( Boeing barrels and the
Airbus tailsections are done on male moulds. Female mould gives you
perfect surface for the "use"/visible side.
And most/all of the surface is done with prepreg fabrics and rovings
and not with a slow tapelayer.
The manufacturing future goes the towards large pieces of CF fabrics
and rovings sewn together with fine structure like windowframes,
doorframes, stringers, ... getting difusion resin impregnation on
a female mould. i.e. the mould is loaded with a sheet of resin, on top
goes the prepared structure cloth a pressure membrane next and
the whole assembly is heated under vacuum suction ( process for the
pressure bulkhead currently.)
http://www.c-technologie.com/Downloads/Resininfusion1.pdf
http://www.google.com/search?q=CFRP+pressure+bulkhead

Airbus argument is that a nonclosed loop workpiece will always
allow better process and quality control than a barrel section
resulting in better quality and/or lower manufacturing cost.
( going by the problems Alenia forex has with tape "folding" and the
less than perfect fit of barrel sections this does seem to carry
some truth.)
Post by JF Mezei
How will they mount such a large spine-less panel to the frame ? Would
they use succion cups to lift/support it while it is mated to the
structure until there are enough rivets to keep it attached ?
That's why I would like to have an inside picture
to see how much structure is cocured to the skin.
my guess is stringers, windowframes, attachment points, all the small stuff you
traditionally rivet on.
Post by JF Mezei
Or does it have enough stiffness that they can grab it by the top and
lift it into position and it would retain its curved shape even if
grabbed by one side ?
Even if it deforms slightly you won't stress it beyond capabilities.

uwe
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Uwe Klein
2011-03-19 09:59:10 UTC
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Aerotec Augsburg has some educational material on their site:

http://www.premium-aerotec.com/
http://www.premium-aerotec.com/en/Aerostructures.html
http://www.premium-aerotec.com/en/Fuselage.html

Good overview how the pieces are "jigged".

uwe
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