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Largest A350 Panel Produced  
User currently offlineaviationbuff From India, joined Mar 2008, 1425 posts, RR: 3
Posted (3 years 5 months 6 days 23 hours ago) and read 13763 times:

Airbus' German plant produces largest A350 panel

http://www.flightglobal.com/articles...t-produces-largest-a350-panel.html

Quote:
German manufacturing operation Premium Aerotech has produced the largest carbonfibre fuselage panel for the Airbus A350 twinjet.

The aerostructure will be located on the starboard side of the aircraft and become part of the primary forward fuselage section 13-14.

Airbus says the panel is 93m² (1,000ft²) in area and was created at Premium Aerotech's Nordenham production facility. The section includes cut-outs for the second right-hand passenger door and lower-deck cargo door.

"[We] opted for large fuselage panels for the A350 design as they can be tailored in terms of their thickness according to the different loads required at each part of the airframe," it states.

"This approach enables Airbus to optimise the airframe overall which results in enhanced performance, greater robustness and less weight."


26 replies: All unread, showing first 25:
 
User currently offlineKC135TopBoom From United States of America, joined Jan 2005, 12134 posts, RR: 51
Reply 1, posted (3 years 5 months 6 days 23 hours ago) and read 13706 times:

Why aren't the windows cut out too?

User currently offlineoly720man From United Kingdom, joined May 2004, 6696 posts, RR: 11
Reply 2, posted (3 years 5 months 6 days 23 hours ago) and read 13690 times:

Quoting KC135TopBoom (Reply 1):

Just thinking that as well. I thought machining CF risked introducing cracks. Maybe all the window holes would have made the mould too complicated?

Or, the window holes would be a potential weakness before the fuselage was completed?

[Edited 2011-03-18 10:13:14]


wheat and dairy can screw up your brain
User currently offlinebrons2 From United States of America, joined Sep 2001, 3010 posts, RR: 4
Reply 3, posted (3 years 5 months 6 days 23 hours ago) and read 13644 times:

Sweet looking assembly.  


Firings, if well done, are good for employee morale.
User currently offlinetrex8 From United States of America, joined Nov 2002, 4745 posts, RR: 14
Reply 4, posted (3 years 5 months 6 days 23 hours ago) and read 13550 times:
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What do they do with the 787 barrel for the doors/windows?

User currently offlineeatmybologna From France, joined Apr 2005, 412 posts, RR: 0
Reply 5, posted (3 years 5 months 6 days 22 hours ago) and read 13421 times:

Quoting KC135TopBoom (Reply 1):
Why aren't the windows cut out too?

The door openings you see are probably only rough in size. Premium Aerotech's Nordenham production facility will now drill and precision trim all of the cut out features such as windows, edges, clearances for the wing box, and the roughed out openings of the passenger & cargo doors.

I'm guessing that because of the occurrence of some distortion, shrinkage, or growth during the curing process (autoclave, ) the rough sized passenger window openings were not considered. There would be too much risk for the barrel shape to deviate from nominal.



Isn't knowledge more than just the acquisition of information? Shouldn't the acquired information be correct?
User currently offlinecloudyapple From Hong Kong, joined Jul 2005, 2454 posts, RR: 10
Reply 6, posted (3 years 5 months 6 days 22 hours ago) and read 13252 times:

Quoting eatmybologna (Reply 5):
I'm guessing that because of the occurrence of some distortion, shrinkage, or growth during the curing process (autoclave, ) the rough sized passenger window openings were not considered. There would be too much risk for the barrel shape to deviate from nominal.

Yep. Very very difficult to bake to precision with the windows.



A310/A319/20/21/A332/3/A343/6/A388/B732/5/7/8/B742/S/4/B752/B763/B772/3/W/E145/J41/MD11/83/90
User currently offlinebikerthai From United States of America, joined Apr 2010, 2093 posts, RR: 4
Reply 7, posted (3 years 5 months 6 days 21 hours ago) and read 13094 times:

Quoting oly720man (Reply 2):
Just thinking that as well. I thought machining CF risked introducing cracks. Maybe all the window holes would have made the mould too complicated?

Machining or water jet trimming of CFRP is acceptable. Cracking is not a problem with CFRP, delamination at the trim edge is.

Quoting eatmybologna (Reply 5):
I'm guessing that because of the occurrence of some distortion, shrinkage, or growth during the curing process (autoclave, ) the rough sized passenger window openings were not considered.

Since this panel was layed up most likely with a automated tape layer, including the cuttout in the pre-cured part would not only involve complicated tape drops and adds that really slows the machine down. Besides, the tape drops are 1/4 inch interval which makes it impossible to lay a straight edge for anything other than 0 or 90.

Once you drop of the tape, you have to fill the void with some sort of tooling to keep the edge true during cure. (If you add the fixture ahead of time, then the tape laying machine will have problem negotiation the step on the fixture). The tooling (if not properly matched with the thermal coeficient of expansion of the cured composite) would induce preloaded stress into the window cutout. You don't want pre-loaded stress in the window cut out.

And Dang . . . that is one impressive panel!!!!  Wow!

bikerthai

[Edited 2011-03-18 11:57:25]

[Edited 2011-03-18 12:00:12]


Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlinebikerthai From United States of America, joined Apr 2010, 2093 posts, RR: 4
Reply 8, posted (3 years 5 months 6 days 21 hours ago) and read 13053 times:

Quoting KC135TopBoom (Reply 1):
Why aren't the windows cut out too?

This may be just a trial demonstration. Windows may be added later or on a later demonstration part.

Quoting aviationbuff (Thread starter):
"[We] opted for large fuselage panels for the A350 design as they can be tailored in terms of their thickness according to the different loads required at each part of the airframe," it states.

"This approach enables Airbus to optimise the airframe overall which results in enhanced performance, greater robustness and less weight."

Red herring . . . optimization can be done with panels or barrel design.

Did I mention that the panel size is quite impressive?   

bikerthai



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineStitch From United States of America, joined Jul 2005, 30867 posts, RR: 86
Reply 9, posted (3 years 5 months 6 days 20 hours ago) and read 12878 times:
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Quoting trex8 (Reply 4):
What do they do with the 787 barrel for the doors/windows?

I recall seeing a picture of a Section 41 fuselage section in the tape-laying mandrel at Spirit and I believe no openings were present. So if my recollection is correct, they are cut out after the fuselage section has been laid down and cured.


User currently offlineikramerica From United States of America, joined May 2005, 21502 posts, RR: 60
Reply 10, posted (3 years 5 months 6 days 20 hours ago) and read 12783 times:

Quoting bikerthai (Reply 8):
Red herring . . . optimization can be done with panels or barrel design.

I know. When I read that, I was all "whaaaaa?!" The whole point of the precision tape laying is that you can optimize thickness throughout the process. Not sure how it's easier to do so on a 60 degree arced panel vs a full round panel.

What Airbus should be touting is the easier production and delivery process, the lack of complexity of manufacture, etc. That's a valuable asset of the program, when compared to Boeing's problems getting full barrels manufactured correctly and delivered easily.



Of all the things to worry about... the Wookie has no pants.
User currently offlineEPA001 From Netherlands, joined Sep 2006, 4721 posts, RR: 39
Reply 11, posted (3 years 5 months 6 days 20 hours ago) and read 12581 times:
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Quoting bikerthai (Reply 7):
And Dang . . . that is one impressive panel!!!!

It sure is. Good to see the progress on the production of the parts that will become the first A350-XWB.  .


User currently offlinebikerthai From United States of America, joined Apr 2010, 2093 posts, RR: 4
Reply 12, posted (3 years 5 months 6 days 18 hours ago) and read 12326 times:

Quoting ikramerica (Reply 10):
What Airbus should be touting is the easier production and delivery process, the lack of complexity of manufacture, etc.

I'll wait until they finish drilling up the many close tolerance holes for the splice joints and install all the titanium fasteners.   

Will they have a machine on a jig to do this? Drilling it up by hand would be a pain!   

bikerthai



Intelligent seeks knowledge. Enlightened seeks wisdom.
User currently offlineseabosdca From United States of America, joined Sep 2007, 5382 posts, RR: 4
Reply 13, posted (3 years 5 months 6 days 18 hours ago) and read 12309 times:

Quoting bikerthai (Reply 8):
Did I mention that the panel size is quite impressive?

Is this thread going to turn into a panel-waving contest?   


User currently offlineruscoe From Australia, joined Aug 1999, 1557 posts, RR: 2
Reply 14, posted (3 years 5 months 6 days 18 hours ago) and read 12239 times:

How is the load gpiong to be transferred from one panel to the next? I understand they will no be overlapped.

One ofd the disadvantages of this is a more comples structure on which to lay the panels.

But it sure is an impressive piece of work.

And good to be seeing some progress for the interest of enthusiasts.

Ruscoe


User currently offlineferpe From France, joined Nov 2010, 2803 posts, RR: 59
Reply 15, posted (3 years 5 months 6 days 17 hours ago) and read 12119 times:

It would be interessting if someone could analyse the amount of fasteners in a certain body lenght compared with the amount of fasteners in the 787 per body lenght.

B has really emphasized that you end up with less fasteners if you do barrels but I don't know if they ment vs these mega panels.

Somehow I feel it will be pretty close to a wash, but that is just a feel. Would be nice to know. 



Non French in France
User currently offlineCFBFrame From United States of America, joined May 2009, 531 posts, RR: 3
Reply 16, posted (3 years 5 months 6 days 14 hours ago) and read 10337 times:

Looking at the panel and thinking about how you hold that large of a piece in place through an a/c's 30 year life will certainly be interesting. That large panel is going to have to deal with temperature change, and vibrations just to name two. All those fasteners attaching to the frame that's expanding, contracting, and shaking. Man, that is an amazing piece of plastic, and it's really big too. Can anybody explain to me how you control that size panel in assembly and then throughout the aircraft's life? I guess during shop visits panels will be able to be replaced?

User currently offlineStitch From United States of America, joined Jul 2005, 30867 posts, RR: 86
Reply 17, posted (3 years 5 months 6 days 14 hours ago) and read 10304 times:
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Quoting CFBFrame (Reply 16):
I guess during shop visits panels will be able to be replaced?

Airbus has at least implied that panel replacements are feasible, but I would expect they'd require significant downtime. It's not something an Airbus AoG (Aircraft on Ground) team will be able to swap out in 24-48 hours in a hangar.   


User currently offlineCFBFrame From United States of America, joined May 2009, 531 posts, RR: 3
Reply 18, posted (3 years 5 months 6 days 13 hours ago) and read 9733 times:

I never thought they would ever use a panel of this size because of the challenges in fabrication (the potential of micro cracks), assembly (using fasteners), and then in operation. Just a snap in place assembly process I guess. I would assume that a portion of the panel will be replaceable and only in limited cases would an entire panel of this size be replaced. So Stitch you are right that 24 to 48 will certainly be out of the question. Thinking about micro cracks, they may not propagate for years, but when they do things will not be pretty. This and the 787 will be interesting to monitor over a 30 year life. Wow.

User currently offlinetdscanuck From Canada, joined Jan 2006, 12709 posts, RR: 80
Reply 19, posted (3 years 5 months 6 days 12 hours ago) and read 9560 times:

Quoting aviationbuff (Thread starter):
"[We] opted for large fuselage panels for the A350 design as they can be tailored in terms of their thickness according to the different loads required at each part of the airframe," it states.

This is just a goofy claim...although it's certainly true of panels, it's equally true of barrels.

Quoting ikramerica (Reply 10):
The whole point of the precision tape laying is that you can optimize thickness throughout the process. Not sure how it's easier to do so on a 60 degree arced panel vs a full round panel.

What's easier is the tooling...it's fairly easy to make the tool surface of a panel be the aerodynamic surface, so if you want to change thicknesses after tool fabrication, you can just change the layup and use the same tool. A male mandrel for a barrel requires that you actually change the tool to accommodate the changed thickness. The end result is exactly the same (vis a vis thickness) but the panel tooling is easier to build and provides lower cost thickness changes.

Quoting ruscoe (Reply 14):

How is the load gpiong to be transferred from one panel to the next? I understand they will no be overlapped.

If they're not overlapped, it would have to be a butt splice. This is pretty common...it's used on most airliners to join sections, and on some (notably Douglas-heritage Boeings) to do some longitudinal skin splices.

Quoting ferpe (Reply 15):

It would be interessting if someone could analyse the amount of fasteners in a certain body lenght compared with the amount of fasteners in the 787 per body lenght.

B has really emphasized that you end up with less fasteners if you do barrels but I don't know if they ment vs these mega panels.

They did. Panels, even really big ones, have to have more length of splice than equivalently sized barrels. The gain is lower for "mega panels" vs. barrels as compared to conventional Al construction, but it's still a gain.

Quoting CFBFrame (Reply 16):
Can anybody explain to me how you control that size panel in assembly and then throughout the aircraft's life?

During assembly, you do CNC layup on really accurate and thermally matched tooling, then trim to final size after cure (this takes out any variance that showed up during the cure). Once it's cured they don't go anywhere, so through the aircraft life isn't really an issue.

Quoting CFBFrame (Reply 16):
I guess during shop visits panels will be able to be replaced?

Technically yes, but it would be even more work than doing a skin panel replacement today (because it's a bigger part), which is to say....really really really hard and extremely unlikely.

Quoting CFBFrame (Reply 18):
Thinking about micro cracks, they may not propagate for years, but when they do things will not be pretty.

All composites (and all metals) have microcracks. It can't be avoided. One of the huge advantages of composites is that cracks don't propogate nearly as easily as they do in metals, and even when they do propogate the strength reduction is much smaller.

Tom.


User currently offlineCFBFrame From United States of America, joined May 2009, 531 posts, RR: 3
Reply 20, posted (3 years 5 months 6 days 11 hours ago) and read 9135 times:

Quoting tdscanuck (Reply 19):
One of the huge advantages of composites is that cracks don't propogate nearly as easily as they do in metals, and even when they do propogate the strength reduction is much smaller.

Thanks for sharing Tom.


User currently offlinedynamicsguy From Australia, joined Jul 2008, 869 posts, RR: 9
Reply 21, posted (3 years 5 months 6 days 10 hours ago) and read 8930 times:

That's a really impressive lump of composite. I'd love to see a photo showing the other side. Presumably it has integral stringers. Anyone know if the frames are integral or if they're fastened in later?

Quoting bikerthai (Reply 12):
Will they have a machine on a jig to do this? Drilling it up by hand would be a pain!

I would bet on this being done by machine. Drilling and reaming is not too bad, but countersinking composites accurately by hand is an utter pain.


User currently offlineGlideslope From United States of America, joined May 2004, 1611 posts, RR: 0
Reply 22, posted (3 years 5 months 6 days 3 hours ago) and read 6275 times:

Congrats to the Airbus Team. Impressive.

Question: Why is this panel white, and on the 787 they are Tan? Has this piece not been "Cured" yet? Or different combo of composite composition?



To know your Enemy, you must become your Enemy.” Sun Tzu
User currently offlineStitch From United States of America, joined Jul 2005, 30867 posts, RR: 86
Reply 23, posted (3 years 5 months 6 days 1 hour ago) and read 4744 times:
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Quoting Glideslope (Reply 22):
Why is this panel white, and on the 787 they are Tan?

I'm going to guess the panel has already been given a coat of primer? It might also be some type of protective covering applied while it's being handled, which is then removed once it's been attached to the airframe (or just prior to attachment).


User currently offlinedynamicsguy From Australia, joined Jul 2008, 869 posts, RR: 9
Reply 24, posted (3 years 5 months 5 days 20 hours ago) and read 3503 times:

Quoting Glideslope (Reply 22):
Question: Why is this panel white, and on the 787 they are Tan?

It could be a tedlar film or similar. We use tedlar on a lot of our pre-preg parts to give the white finish you see, although it's usually on the inner surfce rather than the outer mould line. The tedlar is cured with the composite part to give it a paint-like finish.

As for the 787, I've always wondered what it is which give it the tan appearance. They're definitely black on the inside.


25 Post contains images astuteman : And that guy. Lifting it up. All on his own...... Rgds
26 bikerthai : You can get an approximate by using the following assumptions: 1) Fasteners will either be 1/4" or 3/16" dia. with the majority being 3/16" 2) Fasten
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