Saturday, 20 May 2006 - 11:52 PM BST

I think you mean a convair 990. Different type of plane and one that had a fatal flaw, it looked like it was on fire.

http://en.wikipedia.org/wiki/Convair_990

The Airbus is still faster.

Sunday, 21 May 2006 - 5:53 PM BST

As you approach Mach 1.0 you come across many engineering problems.

Concorde would stretch by over 6 inches due to the heating effect of friction.

That is why the Concorde was a small aircraft, with a jet bomber type design, and an uneconomical number of passengers.

Only the one crash in 25 years of service but enough of an excuse to get rid of the loss maker.

Building a supersonic airliner to carry 747 passengers is not feasible.

Sunday, 21 May 2006 - 7:42 PM BST

Both the comments I have had so far seem to be addressing the italicised part of my post, which is in fact a direct lift from Roger Kirkham's blog. I've written to Roger to let him know that people have expressed opinions. Personally, I don't see there being a replacement for Concorde. An engineering triumph in its own right perhaps, but not commercially viable as far as I can make out. But Roger may know different.

I think fuel economy will be a bigger issue in the future too.

DY

Monday, 22 May 2006 - 12:35 AM BST

I'm greatful to David for remembering a post I'd completely forgotten about!

Apologies in advance for what may be the most boring reply ever... Right, here we go:

Comparing the speeds of aircraft is a notoriously difficult task as it depends on a load of factors, the most important being height - basically the thinner the air the faster the plane will go, but on the flip side the thinner the air the less efficient the turbofans are. In practice this means every aircraft has an optimum altitude for level flight which is a compromise between engine efficency and airframe efficiency. Confusing things further is an aircraft's maximum speed and it's crusing speed, - a rough rule of thumb is cruise is somewhere between 85%-95% of the maximum turbofan speed. And we haven't even mentioned various weight factors like fuel load and payload.

Commercial aircraft are designed to make money for their operators (duh!). Over the past few decades, the requirements of fuel efficiency and noise suppression have been more important to engine and aircraft designers than outright speed. In practice this means modern aircraft are very quiet and fuel efficient compared to older designs, but alas, slower too.

When I made my post about the A380, I spent a bit of time researching the relative speeds of it and the 747, and was delighted to learn it was a bit faster. Now the BBC are saying it's a tiny fraction slower (Mach 0.005 or roughly 4 mph). This probably means one or more of the following:

1) I screwed up my research.

2) Airbus have modified their numbers as a result of flight testing.

3) The BBC have got it wrong.

4) There may be a slight difference between the engine option - Pratt & Whitney or Rolls Royce.

5) [Insert your own reason here].

On a personal note, a friend who lives in Bristol saw the aircraft fly directly overhead at low altitude on its way back from a short air display at Filton, where they make the wings, undercarriage and various other components of the A380. She reported it was an impressive sight, and she was spooked by how quiet it was.

****

Regarding the comments about absolute speed and Concorde.

It's absolutely true that as speed rises so does the drag squared, and at about Mach 0.85 things get complicated by a sort of wave effect that builds up causing considerably more friction. So yes, it takes considerably more power to fly at say Mach 0.9 than Mach 0.85 But that doesn't mean it's impossible to envisage civil aircraft flying at Mach 0.9, given decades of research - it's just the research has gone in different directions - fuel economy and quietness.

As for a possible Concorde replacement - I'm certain it'll happen one day, but not anytime soon.

Pity :-(

Wednesday, 24 May 2006 - 11:57 PM BST

Well they certainly are limited as how fast they can go in populated areas. They must stay under the speed of sound which varies according to atmospheric pressure altitude and temperature. But it hovers somewhere around 600 mph.

I've never minded the extra time. I figure it give me more time to chat with the large snoring smelly woman sitting next to me. Or a chance to down 3 or 4 more Cokes (still free!!!!) That way i'm nice and wired when I finally do get off the plane.

It's not the planes that need to get faster, it's the wonderful people who drag all their luggage onto the plane and can't figure out why they're huge 6 foot tall "carry on" doesn't fit in the overhead compartment. Then we all get to wait as Larry and Sue "change seats" with me so they can sit together since they were too short sighted to choose their flight and seats in advance.

Then of course there's the people who board the plane out of order thinking they'll get to their seat faster if they board with the first class passengers. Not realizing that if everyone behind them is trying to get to row 22 and above, that we'll all have to wait for them to sit down in row 6.

Planes aren't too slow, passengers are still too dumb.