Why We're Not Going To See Sub-orbital Airliners

glowend writes: Sci-fi author Charlie Stross has an article about sub-orbital flight, and why we'll never see it as a common mode of transportation. Quoting: "Yes, we can save some fuel by travelling above the atmosphere and cutting air resistance, but it's not a free lunch: you expend energy getting up to altitude and speed, and the fuel burn for going faster rises nonlinearly with speed. Concorde, flying trans-Atlantic at Mach 2.0, burned about the same amount of fuel as a Boeing 747 of similar vintage flying trans-Atlantic at Mach 0.85 ... while carrying less than a quarter as many passengers. Rockets aren't a magic technology. Neither are hybrid hypersonic air-breathing gadgets like Reaction Engines' Sabre engine. It's going to be a wee bit expensive."

Stross also makes a more general proposition that's particularly interesting to me: "One of the failure modes of extrapolative SF is to assume that just because something is technologically feasible, it will happen. ... Someone has to want it enough to pay for it—and it will be competing with other, possibly more attractive options."

Comments

huh?

[Aighearach]

So, you're not going to see it, because it doesn't save money. Except, it has the potential to be many times faster. Which is a reason to use it that isn't "it costs less." So the argument can't hope to support its thesis. If it happens or not is not based on just if "because we can." It is going to happen or not based on the actual advantages of being faster, their value, and the final cost.

We can certainly say, based on our experience with Concord, that if it is fast enough and safe enough the rich will use it, and if it as safety issues, they will abandon it quickly.

Re:huh?

[Chrisq]

It certainly was loud. I was in the next plane to take off from the same Heathrow runway on several occasions and can tell you that it is the only plane I ever heard above the noise of my own aircraft (usually Tristar, if memory serves). It was worth it! One of the most beautiful planes flying.

I lived under the heathrow flightpath, and in our school, which had sound-proofing, you could still clearly hear Concorde passing over. I remember one day in a lesson it got really loud, so loud that the teacher had to stop talking and some people put their hands over their ears. It turned out that the undercarriage of the plane landing before Concorde had collapsed and Concorde had to abort the landing, which meant using 100% thrust over the noise-abatement area, something that it was not normally allowed to do.

SF Economic Plausibility

[crow]

Yup, this raise one of my big complaints about some SciFi stories: lack of economic plausibility.

Science Fiction is great for looking at how we might deal with various potential technologies. Readers are perfectly happy to suspend disbelief and accept whatever technology is proposed. What readers aren't willing to do is suspend disbelief and accept people behaving implausibly.

To write good science fiction, you need to accurately portray people. You can make up the technology, but you have to get humanity right. And that means you have to get the economics right.

This is exactly the problem I had with reading the Hunger Games. Everything worked, except why would a society with hover cars and other advanced technology have need of the services of the districts? Surely they didn't need coal, and yet they had a whole district dedicated to mining it. The lack of economic sense pulled me out of the book. Instead of thinking about the characters, I was thinking about why the society that was described didn't make any sense.

Re:SF Economic Plausibility

[iluvcapra]

Surely they didn't need coal, and yet they had a whole district dedicated to mining it.

I'm not sure the Ancient Egyptians needed pyramids, either. Europe is also dotted with stupendously huge cathedrals that basically nobody uses anymore, and even when they were built their actual utility or even ecclesiastical justifications were pretty flaky, they were built mostly by towns competing with each other.

The impression I always got from HG was that the society was driven by outright class warfare as a kind of ideology. They didn't make the districts mine coal because they needed it, they made them mine coal because coal mining is a modality of suffering. The only imperative was: the Districts must suffer.

The 20th century is full of examples of state's imposing illogical, and pointless, and wasteful punishments upon people only to demonstrate the state's power. The German Army, when it was retreating from Russia, had to constantly fight with Eichmann's department for train stock and trackage, because moving Jews to concentration camps was actually given a higher priority than troop movements. Or, when Germany made an alliance with a country like Hungary or Croatia, they made it clear that it didn't matter how many army divisions they committed to the German war effort: their loyalty would be measured strictly on the basis of how many Jews and gypsies they expatriated every day.

The whole point is to send a message to everyone: we can punish whoever we want, neither laws, nor efficiency, nor common sense will stop us, so don't cause trouble. Nothing can take a higher priority than that because that's the entire society is founded in coercion and force.

Re:SF Economic Plausibility

[lgw]

Why? Snobbery is not taste, you know. YA genre fiction is often quite entertaining, and the prose quality of the Hunger Games books was fine. While the premise was a bit goofy, the writing was at least consistent.

An adjunct proposition

[ClickOnThis]

An adjunct proposition to consider is that certain technologies will never disappear, no matter how many attractive alternatives arise.

I'll offer one example right now: paper.

Discuss.

While suborbital flight may be too expensive....

[MtViewGuy]

....We may see a return of supersonic flight within the next 15 years.

Thanks to better understanding of how sonic booms are generated from the shape of the plane and definitely way better jet engine technology, we may be able to very soon build a business jet seating 10 passengers capable of flying at Mach 1.6 at ranges up to 6,000 nautical miles with just about no sonic boom audible on the ground even when the plane is fly at Mach 1.6.

How is this possible? First, aerodynamic research using computational fluid dynamics have identified ways to minimize the pressure wave buildup that causes the sonic boom in the first place with very careful shaping of the fuselage and wings. This makes to possible to effectively eliminate the audible sonic at speeds up to Mach 1.6. Secondly, modern engine design using variable cycle engines (GE Aero Engines successfully tested the technology on a engine intended for the Advanced Technology Fighter program that resulted in the F-22A Raptor) means high-bypass turbofan fuel efficiency at subsonic speeds but can change configuration to fly at supersonic speeds with a small amount of reheat (afterburning) to keep fuel consumption and harmful exhaust missions as low as possible. Finally, by keeping the top speed to Mach 1.6, it means less structural heating from flying at supersonic speeds and less need to run a lot of reheat (afterburning) on the engines, which means lower fuel consumption and less need for expensive high-temperature rated stainless steel or titanium structural parts like those used on the Concorde.

I've read companies that sell fractional ownership of private jets such as FlexJet or NetJets would immediately buy 50 of these supersonic business jets once approved for production. The ability to fly from New York City to London in around 4 hours as opposed to the circa 7.5 hours with current jet airliners makes it very attractive to business customers, especially since many live by the motto of "time is money."