SSTs are basically “prestige” planes for the countries that use them and for the people who can afford to fly on them. The problems as I see them are:
Small payload. Only 100 passengers. The cost per seat-mile is great; and even at the exhorbitant prices the airlines charge, they lose money.
They’re “old tech”, designed in the 60s, and using relatively inefficient engines.
They’re noisy. If the fleet were larger, there might be some fiscal logic to using them in an expanded market. But the major market would be the U.S., which prohibits supersonic overflights because of the sonic shockwave. At subsonic speeds, SSTs are very inefficient. The smallest Boeing 737 carries 100 passengers at the same speeds an SST would legally fly in the U.S., and it does it using less fuel in a much less expensive airplane.
Boeing figured out early on that they’d never make money, but the British and the French had to have them. Boeing dropped out of the SST race to concentrate on aircraft that carriers would buy and make money with.
With modern technology we can build supersonic aircraft that burn less fuel, go faster, and carry more people. Even though supersonic flight burns a lot of dead dinosaurs (okay, mostly plants, but you get the idea), they could be viable… if they didn’t create shockwaves. People in this country won’t stand for rattling windows. (Actually, I used to live near Edwards AFB, so I got used to them.) I don’t think the U.S. government will allow SSTs to fly over land here.
A hypersonic transport is being developed, I believe by, or with the input of NASA. I won’t legally be able to use that speed over land, but it would cut many hours off of a trip to Asia. pop Something just popped into my head: Current transport aircraft fly at around 35,000 feet. In case of a loss of pressure, passengers and crew can breath supplemental oxygen from masks. When I went through the altitude chamber at Edwards, we were told that about 50,000 feet the human body needs a pressure suit (similar to what astronauts and SR-71 and TR-1 pilots wear). A hypersonic transport would operate at the fringes of the atmosphere. Could such an aircraft be certified? What if there’s a leak? Will people want to buy their own custom-fitted pressure suits and helmets to ride in it?
Certainly we can build SSTs that carry enough people and have efficient enough engines to be cost-effective. But the demand isn’t there. Although subsonic, our current fleet is quite adequate to move people to all points of the planet. More, we live in a wired world. Many tasks that required a person to be 10,000 miles away can now be accomplished with a mouse-click. It just doesn’t make economic sense at the present time to build a new generation of SSTs.
The Concorde doesn’t have enough range to cross the south Pacific, so New Zealand’s out. Britain just kept them flying for the prestige (you know, kinda like they do with the Queen), and the French probably felt the same way. 25 years later they can still brag about being the only ones to build and operate a successful SST.
I seem to remember that British Airways was privatized several years ago (Thatcher?), so I don’t know if they’re still getting any kind of subsidy. Maybe they figure the losses are worth it for the PR. Scootin’ around at Mach 2 has got to inspire a certain amount of consumer confidence, something you can never have too much of in their business.
As an aside, I heard that if the Concorde were built today, flying it would be prohibited due to noise and pollution laws. Of course, more modern technology may be able to solve some of that, but there you go.
Has there been any consideratiomn of whether SST’s would have military advantages? I suppose they would probably be much less manueverable that subsonic planes.
The SST is dead. Nobody wants sonic booms over their homes, so it is restricted to flights over water, so its not really very cost effective due to restricted flight lanes (amongst many other reasons).
Besides, recent research indicates that SSTs punch huge holes in the ozone layer. So do rocket launches, but that’s another story.
Umm… the Concorde already flies at that altitude. I hear that when the Concorde gets up to cruising altitude, the sky is black, just like the astronauts see it. The Concorde flies up near the top of the troposphere, it IS the edge of space.
You have heard of pressurized cabins, haven’t you? If they had a leak, they’d just drop to a lower altitude and pop out the oxygen masks, like any conventional plane would.
Chas E.
I was not aware that the Concorde flew at those altitudes. In a rapid decompression, there would be a lot of fatalities. At 35,000 feet, people will survive if they paid attention to the flight attendant and use the O2 masks (assuming they weren’t blown out of the whole, and the airframe damage was not too severe). Yes, if it’s a leak they can descend to a lower altitude.
BTW, the rapid decompression was my favourite part of the altitude chamber. There was a bang and the chamber filled with fog. It was fun (on the ground!).
I haven’t heard anything about ‘hypersonic’ planes, but if they are built, they will probably suffer a fate similar to the SST’s. Supersonic flight is very, very expensive, and noone really needs to get anywhere that quickly. The airline that flys the Concord found this out the hard way, and I’m sure that subsidies from Britain and France are the only thing keeping those planes in the air. It sure as hell ain’t the profit margins.
Also, the Concords are getting pretty old, and they’ll probably have to be retired soon. It’s my understanding that no aircraft company is interested in making a replacement plane, so when the Concords go, that’ll be the end of commercial SST, at least for a while.
The hypersonic transport, while not alive and kicking, is still on the books. At one point it was called the “national space plane” but I don’t know whether that’s a current term or not.
Hypersonic passenger transport is probably just eyewash to keep the government funding rolling in. As has been noted above, supersonic travel is expensive and of limited value. How much could it be worth to save an hour or two in this electronic age?
A couple of technical notes:
A more efficient SST could be developed but the operating costs would never be as low as a similar subsonic aircraft. The drag on an aircraft increases drastically as it approaches the speed of sound, leading to fundamentally higher fuel costs. Commercial aircraft operate at a carefully calculated speed – essentially as fast as they can go without getting into the higher drag region.
As far as military applications, the SR-71 Blackbird flies faster than the Concorde and was used for years as a spy plane. I was once lost on a freeway near San Diego with a group including a fellow who was a former Blackbird pilot. As the rest of us were bemoaning our being lost, he said, “You’ve never been lost till you’ve been lost at 2,000 miles an hour!” He also said it “took two states just to turn around.”
Hypersonic flight is still very much a current research area. Our only current hypersonic vehicle is the Space Shuttle and there’s lots and lots of interest in building a replacement. The X-15 topped out at about Mach 6.
As for hypersonic aircraft, the the National Aerospace Plane (NASP) project is dead. The less ambitious followup is the NASA Hyper-X project, aka X-43. According to their web page:
They are currently building three small (12 feet long) unmanned vehicles to test air-breathing engines at Mach 7. It should fly any time now. By the way, a scramjet engine is like a ramjet engine where the incoming air is compressed by the sheer speed of the plane as well as the geometry of the intake nozzle. The difference is that in a ramjet engine, the incoming air is slowed down to subsonic speed, whereas in a scramjet (supersonic ramjet) engine a supersonic flow of air is mixed with fuel and burned. It’s never been tested in flight, as far as I know.