CoolP wrote on Jan 9
th, 2011 at 11:56am:
[quote author=vanislepilot link=1293253550/0#4 date=1294284621]
Mark is right, the original Comet suffered from at least two disasters where the plane disintegrated at cruise level because the fuselage suddenly "exploded" as the compressed air inside found a weak spot to exit its prison. There wasn't any sign of weakness before and no chance to be prepared, it just happened "now".
They later improved the structure (successfully) but the market is hard when the thing has the same name as the tragic predecessor and the competitors are already offering completely new planes, also jet driven. So the Comet sales went down.
I think the actual cause for the fuselage problems were some not proper attached rivets (they weakened the material too much) and those sharp edges at the weak spots (which are the openings, like windows) of the fuselage which seem to focus (or "collect") some fatigue forces then and therefore make them strong. Stronger as calculated to happen on the thin aluminum skin.
They undertook quite some time- and money-consuming investigations on these cases of the Comet. They built a huge watertank for the whole fuselage

to simulate the constant pressurization and depressurization of the structure and tested it for weeks or so 24/7 until it broke and they could prove the design and manufacturing to be the cause for all problems.
A good but sadly live threatening learning process in aviation industry (you won't see sharp edges on modern airplanes flying high and maintaining a relatively low cabin pressure) there to be experienced on the Comet.
I must admit that she gets even more interesting to be done in FSX then.
The Comet4 was perfect and flawless.
The tragedies in series I and II were due to a weak square bolt that induced early fadigue and a crack. This was corrected. Few remember that the Electra and the Boeing 727...yes, the 727, also had early accidents that required them to be grounded in the 60s.
I flew the Comet my whole infancy, it was a second home to me as my father was a Captain. So many long transatlantic flights I made in it...it was so comfortable and silent in a world populated by noisy props. And here I am...alive and kicking.
The Comet Series 4 was a very different aircraft from the original Series 1 of 1952: it was larger, twice as powerful, with better instruments and totally revised structure and materials. It inaugurated the World's first trans-atlantic jet service, and was in service from 1958-1980.
Check this preview
http://www.youtube.com/watch?v=IrRwLJKCJ7w