[HN Gopher] A DH106 1A Comet has been restored at the de Havilla...
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A DH106 1A Comet has been restored at the de Havilland Aircraft
Museum
Author : rmason
Score : 33 points
Date : 2025-07-29 20:14 UTC (3 days ago)
(HTM) web link (www.cnn.com)
(TXT) w3m dump (www.cnn.com)
| dangle1 wrote:
| Such a beautiful plane. While perhaps the structural issues could
| have been better anticipated and addressed, the fact that the
| engines were incorporated into the wings would likely have been
| the next issue for the aircraft, with fires, seized turbofans,
| and proximity to fuel tanks causing further incidents or
| accidents at rates exceeding those of planes with their engines
| mounted on pylons.
| Animats wrote:
| There were later versions of the Comet. Version 1 was
| underpowered, and had too much weight reduction for that
| reason. By version 4, the design had been debugged. With more
| powerful engines and structural fixes, the Comet 4 went into
| service and did OK. 46 Comet 4 aircraft were built. Last flight
| in 1997.
| pinewurst wrote:
| 2011 if you count the Comet-derived Nimrod.
| spankibalt wrote:
| The Sud Aviation _Caravelle_ is a sibling with a different
| engine configuration.
| SoftTalker wrote:
| I remember hearing that the square window cutouts in the original
| Comet concentrated stress in the corners and contributed to
| cracking. But Wikipedia seems to indicate that's not actually
| true. Nevertheless almost all pressurized aircraft now have round
| or oval window and door cutouts, or at least rounded corners.
| hydrogen7800 wrote:
| I thought that too until I read this
|
| >Many readers familiar with the Comet disasters might be
| wondering why, with this article drawing to its close, I have
| yet to utter the phrase "square windows." But the truth is that
| "square windows" never had anything to do with the Comet
| crashes. The windows were not and never were square -- in fact,
| you can see for yourself in the above image, which shows a
| Comet 1 window next to a modern Boeing 737 window. Can you tell
| which is which? You probably can, but not because one is any
| more "square" than the other.[0]
|
| [0]https://admiralcloudberg.medium.com/neither-money-nor-
| manpow...
| quietbritishjim wrote:
| I've heard that counter-rumour before too but it never seems to
| make sense. The lengthy discussion by Admiral Cloudberg [1]
| seems to pin the blame on the corner of a window:
|
| > De Havilland had calculated a maximum operating stress of
| 28,000 psi at the corners of the windows and doors, but
| investigators noted that this value was an average over an area
| of 2-3 square inches (13-19 square centimeters), meaning that
| in theory, highly localized stresses could be considerably
| greater. This "peak stress" could have been measured through
| the liberal application of strain gauges, but de Havilland had
| apparently elected not to attempt this, believing that any more
| precise measurements would be unreliable. Nevertheless,
| investigators measured it anyway, and from these data they
| calculated a localized peak stress at the window corners of up
| to 45,000 psi under normal pressurization conditions. Not only
| was this much greater than de Havilland's predicted value, its
| relative proximity to the ultimate strength of the material
| (estimated to be 65,000 psi) produced an unfavorable stress
| ratio correlating to an expected fatigue life considerably
| below 10,000 cycles.
|
| [1] https://admiralcloudberg.medium.com/neither-money-nor-
| manpow...
|
| I think counter arguments come into one of two camps:
|
| (1) when they replicated the problem in a pressure chamber at
| ground level it wasn't technically a window that failed but a
| "portal" (basically like a window but wires go through it
| instead of people looking out of it) - a pedantic technicality
| and not to say that all the failures in the air were for this
| same portal/window.
|
| (2) The windows weren't don't have sharp corners anyway but
| rounded, not unlike some modern planes. True but you can see
| the failure was definely near a (rounded) corner.
|
| Admittedly the Admiral Cloudberg article does seem to put more
| weight on the way the rivet holes were made than the angularity
| of the window corners. But it's still failing at a corner. I
| guess it depends how you look at it.
| rwmj wrote:
| Cool, my local aircraft museum. The square-windowed Comet was
| rotting in the open for many years but (as the article notes) has
| been restored. They also have a Comet flight deck which you can
| walk around. It has 5 seats on the flight deck (it really is
| huge!), including a flight engineer and a navigator.
|
| Edit: flight deck photo on Wikipedia:
| https://en.wikipedia.org/wiki/De_Havilland_Comet#/media/File...
|
| Other highlights of the museum are a fully restored Mosquito, and
| a Chipmunk (which will be nostalgic for RAF servicemen and cadets
| of a certain age).
| erikig wrote:
| The wing-integrated jets, while not the most efficient,
| maintainable or powerful, are the best looking piece of
| commercial jet engineering in my eyes. Composite winglets are a
| distant second.
| buildsjets wrote:
| Another DH106 Mk4C has been under restoration at the Museum of
| Flight restoration center in Everett, WA since 1995. I don't
| think that a single thing has been done to it since the outbreak
| of the pandemic in 2019. Allegedly they will be losing their
| lease in few years, no idea if they will do anything to complete
| the restoration before then.
|
| https://www.museumofflight.org/exhibits-and-events/aircraft/...
|
| http://www.dhcomet.com/_main/main.htm
| betamaxthetape wrote:
| Note that there is another Comet (4B variant, so one of the later
| ones) preserved at the National Collections Center [1] near
| Swindon. However it is not available to view [2].
|
| [1] -
| https://en.wikipedia.org/wiki/Science_and_Innovation_Park#Na...
|
| [2] - "[Some items] - including large aircraft - ... are
| therefore not featured on the tour."
| https://www.scienceinnovationpark.org.uk/visit-us/public-gui...
| (at the bottom, "Note on Large Aircraft")
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