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Comet crashes...

Posted: 12 Sep 2008, 11:50
by DanKH

Re: Comet crashes...

Posted: 12 Sep 2008, 16:08
by Tako_Kichi
Thanks for that link Dan. I found the episode fascinating but then I was originally trained as an engineer so the behaviour of metals is something I have some understanding of anyway.

I knew the Comets went down due to metal fatigue but for many years I was under the misapprehension that it was metal fatigue in the wing roots that caused the crashes. It was only earlier this year that I discovered it was related to the windows/hatches.

Re: Comet crashes...

Posted: 12 Sep 2008, 19:12
by TSR2
Very interesting how riviting as opposed to gluing the skin couls have such disasterous consequences. Thanks Dan :thumbsup:

Re: Comet crashes...

Posted: 12 Sep 2008, 19:30
by Garry Russell
They just punched them through as well

DH actually produced the fuselage different to how it had been designed..that puts a different light on the whole affair

Garry

Re: Comet crashes...

Posted: 12 Sep 2008, 19:42
by TSR2
I think there was a bit more to it than in the program Garry, the shape of the windows (Square) didn't lend itself to a strong structure as a square metal frame is significantly more stressed at its corners that a circular or mor oval shape. Also the aluminium skin was too thin.

Re: Comet crashes...

Posted: 12 Sep 2008, 19:46
by RobDob
I can't believe they just 'bashed' the rivets through! But maybe that was the norm in those days.

Re: Comet crashes...

Posted: 12 Sep 2008, 19:56
by Garry Russell
There was Ben

But the fatigue failure started from rivet holes that should not have been there.

Maybe there would have been a failure soon but these failures started from those holes.

They had a lot to learn which makes it all the more surprising that for the sake of easier production they used such a poor method of riveting when the design called for bonding.

I saw this video a little while ago now but it must be more than thirty years since I was told the true cause was riveting when the windows should have been bonded......I didn't think too much of it at the time.

Garry

Re: Comet crashes...

Posted: 12 Sep 2008, 23:47
by DispatchDragon
I think one of the most wide spread fallacy's is that DH Engineers "Didnt understand" metalurgy and metal fatigue. What has
always intrigued me is that Neville Shute's book "No Highway" was written 3 years before the crash of 'YP. Many people think that Shute was writing about the Comet crashes - where as he was actually making social comments on the state of the
aircraft industry in the UK at the time and how breaucrat's (The Ministry) who knew little to nothing of aircraft engineering, stress and fatigue were actually making decisions and changes to designs that would endanger peoples lives - DH had a very solid (pun intended) footing and knowledge of bonding materials not just wood but metals as well - simply the Comet was
an aircraft built by committee (Lord Brabizons) and to that end short cuts were taken to speed production and lower costs in a
sales enviroment that was becoming already far to cut throat -- DH had Vickers,Hawker and Bristol all breathing down their necks, even Miles had a long range passenger aircraft drawn up, so they had to cut corners - they did - and the rest is history.

Oh by the way I find Documentaries, (Docudramas) Like this one that graphically show death and destruction a bit off putting did we really need to see bodies floating in the water and flying out of breaking up airframes? would think the
members amongst us - The fishheads who served in the Falklands, people like Techy and Neil will tell those of you who have
not experienced violent death it is nothing to be glorified

Ill take my soap box and leave now

Leif

Sorry I'm in a really Sh*tty mood and watching the piece attached piece of dreck didnt help...Ah Mr Honey -- where are
you when we (the world) need you?

Re: Comet crashes...

Posted: 12 Sep 2008, 23:55
by RobDob
I see your point, but I don't think it was glorified.....just a reasonably accurate reconstruction.

Re: Comet crashes...

Posted: 13 Sep 2008, 05:05
by mgchristy
Slightly off-topic: I was a bit surprised at how young the cockpit crew of Yoke Peter was. Learn something new everyday...

http://www.geocities.com/CapeCanaveral/ ... ogalyp.htm

Captain Gibson: 31yrs
First Officer Bury: 33yrs
Engineer MacDonald: 27yrs
Radio Officer McMahon: 32yrs

I have have no doubt that despite their age the crew were supremely qualified...but I just always assumed that only more senior (age-wise) crews were staffed to jets in the early years. Interesting...