Comments by "" (@neutronalchemist3241) on "A Brief History of: The de Havilland Comet Design Disaster 1954 (Documentary)" video.

There's a reason ships' portholes are not square, and it's exactly the same reason. The designers should have taken the hint.
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In the Comet it was a obliged choice, sinche the engines of the Comet I, Ghost 50 Mk 1, were a little underpowered for the aircraft, so De Havilland used the same "trick" of the Mosquito, that had the radiators in the wings to reduce drag.
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@allangibson2408 On the recovered aircraft it was the antenna mounting (squared holes as well). In the tested one it were the windows. Another problem were the rivets' holes. Punched instead of drilled, they were already microfractured.
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In reality, if you google "de havilland comet windows" you'll see that htey were not really square. They had rounded corners, even if less rounded than modern ones. A successful aircraft as the DC3 had perfectly squared windows, but was not a pressurised aircraft. It's perhaps revealing however that the DC4 (where pressurization was offered as an option) had perfectly round windows.
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@petemaly8950 Since the point of failure had been found to be exactly the corners of the passenger windows and the automatic-direction-finding window t's evident the radiusing was not enough. "just add enough material to make it work" is not a great solution when there are weight constraints, and the material you are working with has not a fatigue limit.
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@petemaly8950 Since both the real-scale tests performed at Farnborough and the analysis of the wrecks shown the points of failures being exactly the corners of the passengers' windows and the automatic-direction-finding window, its' quite evident they didn't test enough before the first flight.
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@petemaly8950 Any time something had not been tested enough, who should have tested it enough was absolutely certain to have tested it enough. It's not like the manufacturer of anything wants to kill some hundred people as a prank. But it's self evident that not enough tests had been performed before the first flight. Unfortunately on aircrafts weight tends to be a factor.
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@petemaly8950 The radiused corners were evidently not radiused enough, since both the real-scale tests performed at Farnborough and the analysis of the wrecks shown the points of failures being exactly the corners of the passengers' windows and the automatic-direction-finding window. "How would De Havilland's have known" is completely immaterial here. What they knew, or didn't, doesn't change where the point of failure was. They would have known had they tested enough or, not testing enough, they could have taken a hint from similar openings that are not square for that very same reason. When the Comet first flew, there already were airliners with oval shaped windows. It's not like the designers chosen that shape due to aesthetic considerations. You know nothing about "my approach". You shouldn't made statement about things you know nothing about.
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@petemaly8950 The radiused corners were evidently not radiused enough, since both the real-scale tests performed at Farnborough and the analysis of the wrecks shown the points of failures being exactly the corners of the passengers' windows and the automatic-direction-finding window, so they didn't "knew" shit. What they thought they knew was wrong. It's fairly simple. Lots of people out there doesn't know what they are talking about. It happens to someone into here as well. When the Comet first flew, there already were airliners with oval shaped windows. It's not like the designers chosen that shape due to aesthetic considerations. So the designers didn't use "all the current, up to date knowledge for the design". Not even close. Fairly straightforward really In real life the Comet G-ALYP was lost due to a fracture starting from the corner of the automatic-direction-finding window. Not enough of the wreckage of the G-ALYY was recovered to establish the cause, of the failure, and the wreckage of the G-ALYV was not investigated enough, even if eyewitness testimony already pointed to a structural failure. In the first test on the G-ALYU the fracture started from the forward escape hatch window, that's identical in shape and structure to the passenger windows. In the second test, the fracture started from the corner of the passenger window N.7. The section of the fuselage with the crack starting from the passenger window is currently on display in the RAF museum at Cosford. So you are wrong again, sorry.
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@petemaly8950 Before conveniently cancelling your post, you stated that no Comet passenger window failed, IRL or in test. Reality is that you don't know enough of two RL incidents out of three to know what failed, and the passenger window failed in one post incident stress test out of two performed (the other time it had been the forward escape hatch window, that's identical in shape and structure to the passenger windows). So 50% of the times. Fact is that the redesigned Comet had the oval shaped windows. Like other airliners already had before the Comet's first flight. Had they done what others already did (and they did because it was known that rounded openings are more resistant to fatigue than squared oned), the windows wouldn't had failed. In reality the inquiry suggested that the designers would have found the design to be defective already with the tests they performed, had they tested real production parts. But they tested instead prototype parts, treated differently than the production ones, and so more resistant to fatigue. Who would have known that tests should be performed on the parts that really end up in the finished product? It's still fairly simple & it's still not difficult to understand, it's a shame you still doesn't seem to be able to activate at least a braincell to grasp it. Your 4 year old grand daughter would have surely been able to give you lessons at this point.
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@petemaly8950 That's your fixation, not mine. "There's a reason ships' portholes are not square, and it's exactly the same reason. The designers should have taken the hint." And they should. There is a reason other airliners had oval shaped windows, and it's exactly the same reason. The designers should have taken the hint. And they should. There is a reason production parts should be tested instead of parts that simply have the same shape. The designers should have know it. And they should. The designers chose the risk. And the airplanes crashed. Stating that "what failed first was in fact irrelevant" is pretty ridiculous. Your 4 year old granddaughter would surely explain it to you. If you don't like forward escape hatch window, that's identical in shape and structure to the passenger windows, the passenger window still failed in 50% of the tests performed, confirming you are wrong again. Your 4 year old granddaughter would surely explain it to you. Provided her existence. Because, having seen your mental ability, at this point, I wouldn't bet on you really knowing the age of your granddaughter, or her existence IRL.
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@petemaly8950 Yet ships almost always have not square portholes, for exactly the same reason. Because ships' hulls are stressed, and there's no reason to build complex reinforces to have square portholes if you can do them round. The designers of the Comet, should have taken the hint.
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@petemaly8950 Because that's your fixation, not mine. "There's a reason ships' portholes are not square, and it's exactly the same reason. The designers should have taken the hint." And they should. There is a reason other airliners had oval shaped windows, and it's exactly the same reason. The designers should have taken the hint. And they should. There is a reason production parts should be tested instead of parts that simply have the same shape. The designers should have know it. And they should. The designers chose the risk. And the airplanes crashed. That the designers didn't made enough tests is a fact. That the windows of the Comet had been designed wrong is a fact. That the windows of the Comet had problems is a fact. That those problems had been eliminated making them oval is a fact. That they wouldn't have had the problem had them being oval from the start is a fact. So: "There's a reason ships' portholes are not square, and it's exactly the same reason. The designers should have taken the hint." And they should.
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@petemaly8950 And here you are lying. I already told you that you don't know enough of two RL incidents out of three to know what failed, AND THE PASSENGER WINDOW FAILED IN ONE POST-INCIDENT STRESS TEAT OUT OF TWO PERFORMED (the other time it had been the forward escape hatch window, that's identical in shape and structure to the passenger windows). SO 50% OF THE TIMES. Fact is that the redesigned Comet had the oval shaped windows. Like other airliners already had before the Comet's first flight. The section of the fuselage with the crack starting from the corner of the PASSENGER WINDOW is currently on display in the RAF museum at Cosford. With a big arrow pointing to the corner of the PASSENGER WINDOW N.7 that says "ORIGIN OF THE FAILURE". Stop lying please. To say that "failure start points are irrelevant" is ridiculous. The failure start points are what made the aircrafts crash, as it would be simple & very easily understood by anyone with a functioning brain . To say that "De Havilland proved through extensive testing that the aircraft design was good" is hilarious, since the design was faulty and caused the crashes, and you can't "prove" what's false. Something your'daughter's dog would surely be able to lecture you about at this point. Not only, but the "extensive testing" had been made on the wrong pieces. Yeah "There's been lots of serious failures that would have been prevented with more testing". So? Had anyone said that the case of the Comet was unique? Keep in mind however (yeah... like you could..) that you talked about tests. I talked about taking a hint.
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@petemaly8950 It's sad to see you have resorted to lying. I already told you that you don't know enough of two RL incidents out of three to know what failed, AND THE PASSENGER WINDOW FAILED IN ONE POST-INCIDENT STRESS TEST OUT OF TWO PERFORMED (the other time it had been the forward escape hatch window, that's identical in shape and structure to the passenger windows). SO 50% OF THE TIMES. Fact is that the redesigned Comet had the oval shaped windows. Like other airliners already had before the Comet's first flight. The section of the fuselage with the crack starting from the corner of the PASSENGER WINDOW is currently on display in the RAF museum at Cosford. With a big arrow pointing to the corner of the PASSENGER WINDOW N.7 that says "ORIGIN OF THE FAILURE". The window of the front escape hatches, that failed in the the first post-incident stress test had the same shape, structure and dimension than the passenger window. the rear one was bigger. To say that "failure start points are irrelevant" is ridiculous. The failure start points are what made the aircrafts crash, as it would be simple & very easily understood by anyone with a functioning brain. To say that "De Havilland proved through extensive testing that the aircraft design was good" is hilarious, since the design was faulty and caused the crashes, and you can't "prove" what's false. Something even teh fleas on your'daughter's hamster would surely be able to lecture you about at this point. And here you are lying again, since the testing having been made on the wrong pieces is one of the conclusions of the inquiry. Yeah "There's been lots of serious failures that would have been prevented with more testing". So? Had anyone said that the case of the Comet was unique? Keep in mind however (yeah... like you could..) that you talked about tests. I talked about taking a hint.
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@petemaly8950 Wrong again. Simple stuff, for anyone but you. You can't "prove" what's false. "as far as they were concerned" count for any testing ever mande on anything that proved to be defective introduced on the market "as far as they were concerned it was safe". But it wasn't. Very very basic stuff, not at all difficult, for anyone but you. Any of your family's pet and various insect around the house could lecture you on the matter at this point. And you keep on lying. I already told you that you don't know enough of two RL incidents out of three to know what failed, AND THE PASSENGER WINDOW FAILED IN ONE POST-INCIDENT STRESS TEST OUT OF TWO PERFORMED (the other time it had been the forward escape hatch window, that's identical in shape and structure to the passenger windows). SO 50% OF THE TIMES. Fact is that the redesigned Comet had the oval shaped windows. Like other airliners already had before the Comet's first flight. The section of the fuselage with the crack starting from the corner of the PASSENGER WINDOW is currently on display in the RAF museum at Cosford. With a big arrow pointing to the corner of the PASSENGER WINDOW N.7 that says "ORIGIN OF THE FAILURE". The window of the front escape hatches, that failed in the the first post-incident stress test had the same shape, structure and dimension than the passenger window. the rear one was bigger. To say that "failure start points are irrelevant" is ridiculous. The failure start points are what made the aircrafts crash, as it would be simple & very easily understood by anyone with a functioning brain. To say that "De Havilland proved through extensive testing that the aircraft design was good" is hilarious, since the design was faulty and caused the crashes, and you can't "prove" what's false. Something even teh fleas on your'daughter's dog would surely be able to lecture you about at this point. Not only, but the "extensive testing" had been made on the wrong pieces. Yeah "There's been lots of serious failures that would have been prevented with more testing". So? Had anyone said that the case of the Comet was unique? Keep in mind however (yeah... like you could..) that you talked about tests. I talked about taking a hint.
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@petemaly8950 Evidently they didn't, since the planes crashed due to design flaws that other designers avoided.
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@petemaly8950 They evidently didn't, since their products crashed due to the faulty design, while other aircrafts of the era didn't. Unless you are insinuating they did that on purpose.
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It's quite fampus among WWII aircrafts aficionados, since it built the "Mosquito" light bomber. One of the most successful aircrafts of the conflict.
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@sandervanderkammen9230 We don't know. Only one of the three fuselages had been recovered and studied.
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It seems that the Comet had a particular liking for the Ciampino airport. Three out of five incidents (and two explosive decompressions out of three) happened to aircrafts that took off (or attempted to) from there.
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Not that shortly. The 737 IE, introduced in 1968, used very slim low bypass turbo fans until the second generation was introduced in 1979.
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