Commercial flights faster than sound

[cpast]

I watched Flightradar24 carefully and noticed that long-haul flights usually fly 10% faster than those on short flights. In a short flight, cruise is just about 50-70% of time, so 10% faster means 5..7% faster flight. On long flights, cruise is about 90% of time.

Are you sure it's showing airspeed? Ground speed depends on winds aloft, which can be very fast (and so have a huge impact on ground speed).

[AngelLestat]

Here there is good info about efficiencies, speeds and why there is a big change after 0.85% in fuel consumption.

http://en.wikipedia.org/wiki/Energy_efficiency_in_transportation#Aircraft

[Sidereus]

The noise was a bit of an overblown problem. Nobody complains about sonic booms from military jets or the space shuttle. The real reason it became an issue in the US was protectionism with Boeing, Lockheed and McDonnell-Douglas's strong lobbying to ban supersonic jets. With the ban, the only viable routes became Paris/London-New York, which made Concorde uneconomical.

There's two big problems with this: People DID complain about sonic booms from military jets, and they were eventually restricted from going supersonic overland in many circumstances as well. I used to live relatively near NAS Fallon in Nevada (well, "close" in supersonic jet terms - I was around 200 miles away) and I remember hearing sonic booms fairly regularly up until the mid '90s or so, after which they stopped completely. From what I understand, they're still mostly allowed to go supersonic above 10,000 feet, but rarely do so over inhabited areas for public relations reasons. They can only go supersonic under 10,000 feet in very limited circumstances. A lot of people really don't like sonic booms.

The second is that the restrictions on the Concorde started in the late '70s. The plane flew for another 20+ years before retirement. It may have hurt sales a bit, but there isn't any indication that was some kind of a death blow.

As for overland supersonic, I have no idea how much noise Concorde made at cruising attitude. An modern supersonic plane can be made so you don't hear the boom on ground.

AFAIK, the technology for that is still in the testing stages, though the last time I read anything about it was probably five or so years ago... ETA: Just rectified that. It does indeed still seem to be in testing stages, at least as of early 2014.

Edited April 1, 2015 by Sidereus

[Nibb31]

The second is that the restrictions on the Concorde started in the late '70s. The plane flew for another 20+ years before retirement. It may have hurt sales a bit, but there isn't any indication that was some kind of a death blow.

The airlines operated the handlful of Concordes that they got, because well, the planes were purchased and delivered, so they might as well have flown them. But the production was given a death blow by the early 70's with the 1973 Oil Crisis and lobbying from the US manufacturers. British Airlines and Air France managed to operate them profitably, but BAe and Aerospatiale didn't make any money on the Concorde.

[Sidereus]

The airlines operated the handlful of Concordes that they got, because well, the planes were purchased and delivered, so they might as well have flown them. But the production was given a death blow by the early 70's with the 1973 Oil Crisis and lobbying from the US manufacturers. British Airlines and Air France managed to operate them profitably, but BAe and Aerospatiale didn't make any money on the Concorde.

That doesn't seem to have been true, at least for British Airways. They seem to have made a pretty decent profit around £30-50 million per year during peak years. They also made a profit just prior to retirement, as the last flights were all booked solid. In total, they made £1.75 billion in profit for £1 billion in operating costs, which isn't all that bad.

http://www.concordesst.com/retire/faq_r.html

http://www.bloomberg.com/apps/news?pid=newsarchive&sid=ayK_dRjyq3Tc&refer=europe

You also ignored the first part of that section. It wasn't just the lobbying of the US manufacturers, there were and are a LOT of people who simply don't want to hear sonic booms going overhead to the point where they mostly stopped the US military from doing it over inhabited areas. I think that even if the Boeing or any other US manufacturer had developed a supersonic airliner, it'd have been banned from going supersonic overland as well. That's a serious obstacle that any manufacturer who designs supersonic civilian aircraft is going to have to overcome.

Edited April 1, 2015 by Sidereus

[Nibb31]

BAe = British Aerospace, not British Airways. Both BAe and Aerospatiale lost money on the 15-year development program and only sold 14 aircraft. Those manufacturers were strongly backed by the government, so British and French taxpayers footed the bill for Concorde in the end.

But I specifically said that British Airways and Air France did operate them profitably mainly thanks to the luxury niche pricing.

Edited April 1, 2015 by Nibb31

[Iskierka]

That doesn't seem to have been true, at least for British Airways. They seem to have made a pretty decent profit around £30-50 million per year during peak years. They also made a profit just prior to retirement, as the last flights were all booked solid. In total, they made £1.75 billion in profit for £1 billion in operating costs, which isn't all that bad.

You also ignored the first part of that section. It wasn't just the lobbying of the US manufacturers, there were and are a LOT of people who simply don't want to hear sonic booms going overhead to the point where they mostly stopped the US military from doing it over inhabited areas. I think that even if the Boeing or any other US manufacturer had developed a supersonic airliner, it'd have been banned from going supersonic overland as well. That's a serious obstacle that any manufacturer who designs supersonic civilian aircraft is going to have to overcome.

To ensure that the vehicle entered service, BA and AF had special contracts that their initial orders could be to purchase the aircraft for a value of just £1 each (possibly 1 frank for AF, but BA paid £1). BAe and Aerospatiale, the manufacturers, most definitely did not make a profit - though governments funding the development mean they didn't specifically lose money on the project, just broke even.

Also, it was just the lobbying of US manufacturers. Most people didn't think Concorde would be loud enough to be a problem initially, and indeed it was quieter than many aircraft of the time. Why did people start complaining? Because US manufacturers lobbied, and made overblown PSAs, and did everything they could to make people think there was a problem that didn't particularly exist, so that the US government had to cave and give the bans they requested. The knock-on effects of this is that the rest of the world found out what was going on, heard things about "supersonic aircraft are loud", assumed that the truth was being told and the aircraft were as loud as claimed at the time (again, they weren't), and so very few countries in the world lack a ban on supersonic flight - those that do likely lack any rules around flight. If a US manufacturer had successfully developed an SST, then you can be absolutely certain, supersonic overland flight would've been legal for at least decades longer, as they'd've done everything in their power to do the exact opposite of what they used everything in their power to do initially.

And yes, all the techniques for reducing sonic booms are technically purely experimental. This is purely because there is no vehicle, in flight or in development, able to use them - military aircraft have much greater freedom so do not need reduced sonic boom unless it also provides greater efficiency with no other losses, and there are no commercial vehicles that would have significantly gained from the techniques. If you could somehow convince someone to develop an SST now, it would be incredibly quiet, especially compared with military aircraft that is most people's only idea of sonic booms - but no-one thinks that's the case, and because of that you can't fly most of the useful SST routes, and so no airline is interested in an SST, and so no manufacturer is interested in developing an SST, and so these technologies remain ideas in a lab. Sometimes they get applied to UAVs and proven, but largely they remain ideas in a lab.

All because the US threw a hissy fit over losing the SST race four decades ago.

[cpast]

Also, it was just the lobbying of US manufacturers. Most people didn't think Concorde would be loud enough to be a problem initially, and indeed it was quieter than many aircraft of the time. Why did people start complaining? Because US manufacturers lobbied, and made overblown PSAs, and did everything they could to make people think there was a problem that didn't particularly exist, so that the US government had to cave and give the bans they requested. The knock-on effects of this is that the rest of the world found out what was going on, heard things about "supersonic aircraft are loud", assumed that the truth was being told and the aircraft were as loud as claimed at the time (again, they weren't), and so very few countries in the world lack a ban on supersonic flight - those that do likely lack any rules around flight. If a US manufacturer had successfully developed an SST, then you can be absolutely certain, supersonic overland flight would've been legal for at least decades longer, as they'd've done everything in their power to do the exact opposite of what they used everything in their power to do initially.

This is incorrect. The US ran experiments for sonic booms in preparation for an SST. The majority were OK, but an extremely vocal minority were not. A huge part of cancelling the SST was that these experiments, plus the fact that the government paid little compensation to those affected, led to public outrage. Supersonic flight absolutely *does* cause serious noise issues (just note how every single time fighters go supersonic on an intercept, people notice and complain).

[PakledHostage]

Supersonic flight absolutely *does* cause serious noise issues (just note how every single time fighters go supersonic on an intercept, people notice and complain).

And the sonic booms produced by Concorde were stronger than those produced by a little fighter. I've heard sonic booms from both^* and the Concorde's would literally give you a thump your chest while those from high altitude fighter jets pretty much just sound like thunder.

^*As I've previously explained elsewhere on these forums, I sailed across the Atlantic via a northerly route about 12 years ago. We heard the Concorde go over a good dozen times during that 3 week passage. You'd feel the thump in your chest each time. This despite the fact that it was 50 odd thousand feet up and almost certainly not directly overhead.