Hacker News Board Hacker News, browsed like a classic message board
Live data from Hacker News

The de Havilland Comet changed aviation for good

bbc.com

Post reply on HN
Print view View original

11–20 of 61 posts

Re: The de Havilland Comet changed aviation for good

#11

Post by cromulent »

cdegroot wrote: post #10

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, ...)…

It's down to the laws of physics. They still fly at around 80% of the speed of sound, as that is close to the so-called "coffin corner".

https://en.wikipedia.org/wiki/Coffin_corner_(aerodynamics)

Re: The de Havilland Comet changed aviation for good

#12

Post by dom0 »

cdegroot wrote: post #10

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, ...)…

Well the Concorde was twice as fast (record: 2 hours and 52 minutes), but it's decommissioned now.

Re: The de Havilland Comet changed aviation for good

#13

Post by cstross »

justinph wrote: post #4
mirimir wrote: post #2

It's indeed a beautiful aeroplane. But what's striking, and indeed rather UFO-like, are the small engine intakes. Anyone know what's up with that?

They're turbojet engines, not the turbofans that you see today. Turbojets have a smaller intake and the entire thing produces thrust. Unlike today's much more efficient turbofans, where a small turbojet turns the larger fans to produce most of the thrust.

The Nimrod maritime patrol aircraft was a modified Comet airframe:

https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod

In the early 2000s, BAe Systems had a project in train to upgrade them to the MRA4 spec, essentially remanufacturing the existing MRA2/MRA3 Nimrods around a new wing structure that could accommodate RR BR700 turbofans, doubling the aircraft's range:

https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_MRA4

(Go look at the photos on the respective wikipedia pages and examine the engine inlets at the wing roots: the MRA4's air intakes are much larger.)

The MRA4 upgrade was at least as radical as the proposal to re-engine USAF B-52 bombers with four GE high-bypass turbofans (as seen in the photograph on the web page below, showing a B-52 flying with the new engine in the inboard starboard pod):

http://aviationweek.com/defense/ge-rolls-pratt-vie-b-52-engi...

... Which also got cancelled; in the case of the B-52 the USAF had so many old engines in mothballs that re-engining the B-52 would cost more than just swapping out old units, and in the case of the Nimrod MRA4 the program ran into nightmarish cost-overruns when it became apparent that the aircraft they were trying to remanufacture were all different — the RAF's Nimrod fleet had been hand-built then patched for half a century and simply couldn't be consistently upgrades.

(Moral of story: upgrading a 50+ year old design is harder than it looks.)

Re: The de Havilland Comet changed aviation for good

#14

Post by ak217 »

cdegroot wrote: post #10

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, ...)…

In 1958, the cost of a ticket was about 4x what it is today (adjusted for inflation but not earnings growth), flying was at least 20x less safe in terms of fatal crashes per departure, and consumed at least 4x more fuel per passenger-mile. Those are some impressive performance tweaks.

Re: The de Havilland Comet changed aviation for good

#15

Post by mirimir »

cstross wrote: post #13
justinph wrote: post #4

Earlier quoted context omitted.

They're turbojet engines, not the turbofans that you see today. Turbojets have a smaller intake and the entire thing produces thrust. Unlike today's much more efficient turbofans, where a small turbojet turns the larger fans to produce most of the thrust.

The Nimrod maritime patrol aircraft was a modified Comet airframe: https://en.wikipedia.org/wiki/Hawker_Siddeley_Nimrod In the early 2000s, BAe Systems had a project in train to upgrade them to the MRA4 spec, essentially remanufacturing the existing MRA2/MRA3 Nimrods around a new wing structure that could accommodate RR BR700 turbofans, doubling the aircraft's range: https://en.wikipedia.org/wiki/BAE_Systems_Nimrod_M…

Doh, I never really noticed how small those B-52 engines are. It makes the plane so elegant and insectile.

Re: The de Havilland Comet changed aviation for good

#19

Post by Animats »

cdegroot wrote: post #10

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.

Re: The de Havilland Comet changed aviation for good

#20

Post by douche »

gaius wrote: post #7

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.
Post reply on HN