31–40 of 61 posts
The corner of a square hole in a flat plate has 4x the stress of the surrounding material. It's called a "stress riser". If you look at a concrete slab with such an inside corner, there's usually a crack there. Boeing solved the problem by using rounded windows, and riveting on a forged doubler around the window frame. The skin was also organized so a crack will not propagate far. The success of the latter has shown…
My biggest "surprise" always is how little we have progressed if you just look at how the planes look and how fast they fly (6h11m NY->London in 1958, that's pretty much what they do today, not?). It seems like the airline industry got a lot of stuff just right the first time and since then just has been doing performance tweaks (where I take "performance" to be very broad to include things like safety, economy, ...)…
A little slower today, for fuel economy. Going supersonic uses 3x the fuel. That's what killed the Concorde.
The 757 use to make the SFO-JFK route in a little under 5 hours, these days most flights make it in just under 6 (a 20% increase in time to save fuel).
Air travel is technically capable of big improvements, but economics don't work out.
Such a wasted opportunity. Around the same time, the UK was throwing away its leadership in computing too. Weirdly, both ended up in Seattle.
It's hard to keep up when you've lost the better part of two generations in a row, and most of the stockpiled capital of a century of imperialism - especially when you also lose the empire that generated all that wealth.
Such a wasted opportunity. Around the same time, the UK was throwing away its leadership in computing too. Weirdly, both ended up in Seattle.
It's not as if the UK's contribution to Airbus or other parts of the aviation supply chain today is insubstantial though.
The corner of a square hole in a flat plate has 4x the stress of the surrounding material. It's called a "stress riser". If you look at a concrete slab with such an inside corner, there's usually a crack there. Boeing solved the problem by using rounded windows, and riveting on a forged doubler around the window frame. The skin was also organized so a crack will not propagate far. The success of the latter has shown…
Boeing was by no means the first to use radiused windows in pressurised airliners; the Avro Tudor was doing so in 1946 and there may well have been earlier examples.
Conversely the Boeing Stratoliner was flying with square windows in the early 1940s and didn't suffer fatigue failures, nor did the later DC-6. Corner stresses were understood at the time.
What really undid the Comet was that the fuselage skin gauge was insufficient to accommodate the increased rate of change of pressure differential that was introduced with jet flight. Whereas the preceding piston-engined airliners were lucky to hit 1000 feet per minute climbing to 20,000 ft, the Comet climbed at three times that rate to 35,000 ft +.
The Comet had skin reinforced to 20 swg along the window belt, whereas the succeeding Comet IV had 18 swg with 16 swg framing.
There is a "square windows" Comet 1A in the http://www.dehavillandmuseum.co.uk/ , next to the northern stretch of the M25. Well worth a day out to this quiet little museum (home of the former De Havilland factory) if you live in or around London.
It's surprising the designers made that mistake. Square inside corners were a known problem in shipbuilding.[1] Welding Journal, 1945: "Another contributing failure to welded ship failures is faulty design and in this category the inclusion of square corners is by far the most common and most detrimental. Occasionally some form of square corner will slip by the designer and and draftsman ... Supervisors should call i…
My biggest "surprise" always is how little we have progressed if you just look at how the planes look and how fast they fly (6h11m NY->London in 1958, that's pretty much what they do today, not?). It seems like the airline industry got a lot of stuff just right the first time and since then just has been doing performance tweaks (where I take "performance" to be very broad to include things like safety, economy, ...)…
Not quite the first time: by looking at 1958, the start of the jet age, you have deliberately set as your starting-point the exact point at which they got things right, along that particular dimension (speed). Prop planes such as the DC-3 were most certainly slower.
But it's true that commercial airliners have not got much faster over the past 50 years, and that's, as other replies to your comment point out, down to the speed of sound.
I like the De Havilland story in how it made the managers look like fools: 2 crashes in bad weather, +1 in good weather, a worldwide suspension of operations, resumed a fortnight later with reassuring words from the management, +1 another crash, then a more serious stress test (which should have been done since the beginning), with negative results, then a bankruptcy... Fortunately, that's what happens to the wrong c…
It is possible to extinguish a small fire with jet fuel. Don't try this at home.
Earlier quoted context omitted.
It's hard to keep up when you've lost the better part of two generations in a row, and most of the stockpiled capital of a century of imperialism - especially when you also lose the empire that generated all that wealth.
I've often argued that the root cause for loss of empire, was the best and brightest of a generation was left on Flanders fields. The best and brightest of the ruling class at the time was simple used up as cannon fodder, its also the cause for the decline of the aristocracy too.
The loss of empire was after WW2 not WW1, and partly due to the US insisting (Suez) and partly because it became morally and economically impossible to subdue (Mau Mau etc.). The postwar British disease was labour relations, which were handled far better in Germany with worker representatives at board level.
(I might argue far more cynically that the aristocracy was by definition not a meritocracy, and that only its violent destruction by war enabled Europe to have a chance at becoming more egalitarian.)
The corner of a square hole in a flat plate has 4x the stress of the surrounding material. It's called a "stress riser". If you look at a concrete slab with such an inside corner, there's usually a crack there. Boeing solved the problem by using rounded windows, and riveting on a forged doubler around the window frame. The skin was also organized so a crack will not propagate far. The success of the latter has shown…
> Boeing solved the problem by using rounded windows, and riveting on a forged doubler around the window frame. Boeing was by no means the first to use radiused windows in pressurised airliners; the Avro Tudor was doing so in 1946 and there may well have been earlier examples. Conversely the Boeing Stratoliner was flying with square windows in the early 1940s and didn't suffer fatigue failures, nor did the later DC-6…