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Old 29th May 2012, 12:47   #121 (permalink)
 
Join Date: Aug 2011
Location: Grassy Valley
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Looking beyond the courage of Ender's remarks, things look worse than thought. It can be said that the culture at Airbus has been less than forthcoming, so as well as refreshing, the comments speak to the gravity of the situation. For eighteen months, a/c will be completed with materials that will fail, and involve serious downtime and cost that is staggering in their repair. Meanwhile, a/c fly with fractured ribs, looking at several milions in repair sooner or later.

Boeing is not immune; the storied delays may in the long run be a saving grace. However, a giant leap into new and untested technology (tested in long term).

In the case of the three-eighty, an ironic failure, naturally in pursuit of profit. Eventually a/c will fly as anorexic hangar queens? Light, Strong.........and Durable?
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Old 29th Aug 2012, 13:00   #122 (permalink)


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Cool

One correction to this post. Only the upper surface wing panels of the A380 are creep formed during the precipitation hardening heat treatment. The lower surface panels on the A380 (as well as A310, A319/20/21, A330 and A340) are shot peen formed. The failing brackets on the A380 attach the ribs to the lower peen formed panels. The photo in this post is, indeed, of an upper surface panel in the autoclave at Broughton, North Wales. I was in charge of the US owned factories in North Wales from 1982 till my retirement in 2005 where all the above named lower Airbus panels were shot peen formed and shot peend along with many other Airbus (and other manufacturers) parts. Shot peening is a specialist cold working surface process which increases resistance to fatigue failure and stress corossion cracking as well is being used to induce form or correct distortion by inducing beneficial residual stresses.
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Old 23rd Sep 2012, 04:52   #123 (permalink)
 
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Is this aircraft safe to fly? The traveling public are led to believe that lots of cracks have been found but it remains safe. Any air frame engineers care to elaborate?
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Old 23rd Sep 2012, 20:02   #124 (permalink)
 
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Retired Peener,

I remember a vid of the upper skin in its machining stage, it was air tabled and routed to thickness. For its profile dimension, the lack of a platten or solid table made it look iffy to get good tolerance over the entire (single!) sheet.

So when the TRENT holed it, I immediately thought, well, there goes the monolithic integrity, they'll patch it. Did they? or did they ship a single sheet of upper skin to Aus, and layer it on site?

Can I assume a rough similarity between shot peening the lower skins to what a Jag scholar or Ferrari assembler would use an English Wheel? (beneficial residual stresses?)

Last edited by Lyman; 23rd Sep 2012 at 20:05.
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