In a post on the Civil Aviation forum the remark was made that Boeing would not use the techneque of spinning a barrel on a mandrel again, because of problems-specifically getting a good enough finish on the outer surface-again. How successful (or unsuccessful) has this construction method been? Has it been a disappointment, and are they making any moves to improve it? Have they had problems joining barrel sections together properly?
[Edited 2016-03-14 08:08:07]
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- WIederling
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RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting SEPilot (Thread starter): |
That was me.
bad fit:
http://www.seattletimes.com/business...-pieces-arent-quite-a-perfect-fit/
IMU fixed with hydraulic presses ( the 777 had the same issue which was only fixed
on the section side in very recent times.
Article afair in the Seattle Times by?Dominic Gates? , though I can't find it atm.)
RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting WIederling (Reply 1): Article afair in the Seattle Times by?Dominic Gates? , though I can't find it atm.) |
I think it is important to note this article is almost 9 years old.
I suspect over that time a lot has been learned about what was then a very new process in a widebody aircraft.
RE: Boeing's Cfrp Barrel Construction: How Successful
The problem that article had nothing to do with barrel production, but was a midfit caused by the way internal structure was installed, causing the barrels to be slightly out of shape. It was nothing but fine tuning of the assembly process.
RE: Boeing's Cfrp Barrel Construction: How Successful
I am interested to find out if the problems have been resolved, and if the production now is going smoothly and producing good parts. In other words, is it meeting expectations now after a large number of frames have been produced? Are there still issues with outside surface quality?
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- VirginFlyer
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RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting L-188 (Reply 2): Quoting WIederling (Reply 1): Article afair in the Seattle Times by?Dominic Gates? , though I can't find it atm.) Originally published June 12, 2007 at 12:00 am Updated June 28, 2007 at 4:14 pm I think it is important to note this article is almost 9 years old. I suspect over that time a lot has been learned about what was then a very new process in a widebody aircraft. |
Indeed. I seem to recall a statement made during the final assembly early on in the process (but I believe after this article) that the fit between components was better than any previous aircraft.
V/F
RE: Boeing's Cfrp Barrel Construction: How Successful
The skins are way smoother due to the much lower fastener count through the skin. They build a barrel every two days.
There was that fire from the ELT battery but Boeing replaced large portion of the barrel section with a very large patch...
I have heard of no groundings due to any interactions with ground equipment.
With 400 or so in service, if there were any real issues we would have heard about it.
I would say its proved its worth.
There was that fire from the ELT battery but Boeing replaced large portion of the barrel section with a very large patch...
I have heard of no groundings due to any interactions with ground equipment.
With 400 or so in service, if there were any real issues we would have heard about it.
I would say its proved its worth.
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- WIederling
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RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting pygmalion (Reply 6): The skins are way smoother due to the much lower fastener count through the skin. |
You'd be surprised how small the difference probably is.
The majority of fasteners is used for window/door framings and attaching the ribs.
IMU the surface problem is that the outer one is formed by applying an elastic matt
on the placed resin impregnated fibers. The circumferential laid fiber pattern pushes through.
Overall surface roughness is increased.
RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting SEPilot (Reply 4): I am interested to find out if the problems have been resolved, and if the production now is going smoothly and producing good parts. |
That appears to be the case considering the current production rate.
Kawasaki started Section 43 for the first 787-10 two weeks ahead of schedule, so they at least appear to be able to pump out barrels at a sustained high rate.
RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting WIederling (Reply 7): You'd be surprised how small the difference probably is. The majority of fasteners is used for window/door framings and attaching the ribs. IMU the surface problem is that the outer one is formed by applying an elastic matt on the placed resin impregnated fibers. The circumferential laid fiber pattern pushes through. Overall surface roughness is increased. |
its more significant than you think it is.. There are metal or composite caul plates and not mats. There is also a surfacer layer on the exterior and no portion of the weave is discernible.
The fastener count through the skin, especially in the forward sections where it really counts, is 10% of that of a metal airplane.
[Edited 2016-03-16 14:08:21]
RE: Boeing's Cfrp Barrel Construction: How Successful
| Quoting pygmalion (Reply 6): have heard of no groundings due to any interactions with ground equipment. |
I have to admit, I was *very, very* skeptical about how it would fare in the real world and thought it would be a disaster when powerpoint ran slap bang into reality... or a baggage cart.
But its very much looking like its working fine - however we'll need to see a few go to full life before being completely sure.
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