The future of air travel?

[Running with Scissors]

While reading Cecil's article (I didn't post this in Comments on Cecil's Columns because it's not really about the column per se) on high-speed rail, it occurred to me that we appear to have no fallback plan to replace air travel once oil prices become too high to support flights on a regular basis (and while I haven't seen a concensus, I figure it has to happen some time in the next half-century or so based on different predictions I've read) - after all, it is a finite resource.

Unlike autos, hybrid planes aren't practical - there's no regenerative braking (except at the very end of a flight) and the hardware would take up too much of the total weight of the plane. Ditto for battery powered planes, barring some miraculous development in battery technology. Even if hydrogen fuel cell technology becomes practical, hydrogen's energy density is significantly lower than that of gasoline/jet fuel.

So my question is: is there a way to keep planes flying in the post-petroleum world?

[Whack-a-Mole]

Pedal powered planes? ;-)

[Giles]

Zeppelins?

[ivn1188]

I think your prediction is of sometime in the next 50 years is a little off, but it's immaterial.

Should it become too expensive, we will simply switch to hydrogen or ethanol or any of the other renewable fuels.

[yabob]

Biofuels are a possibility. Coal to liquids can be done now. South Africa's Sasol has a lot of experience with it, gained during apartheid, when economic embargoes made it hard for them to import oil (South Africa has large coal deposits). More expensive, of course. A lot of coal derived fuel is still used there, made competetive through government subsidy.

[ElvisL1ves]

Biofuels (still hydrocarbons but not fossil fuels) are already well along in development, using several different varieties of vegetation. Synthetic coal-derived fuels have been around since WW2 (still fossil fuels, but supplies not so constrained as petroleum). Realistically there aren't any alternatives to hydrocarbon liquid fuels in sight yet, but there can be breakthroughs in any technology at any time.

You might well see air travel simply become more expensive again, and even more use of telecommunications and the Net instead of much business travel.

[yabob]

Originally Posted by yabob

Biofuels are a possibility. Coal to liquids can be done now. South Africa's Sasol has a lot of experience with it, gained during apartheid, when economic embargoes made it hard for them to import oil (South Africa has large coal deposits). More expensive, of course. A lot of coal derived fuel is still used there, made competetive through government subsidy.

Correction - I don't think the subsidies which allowed Sasol to develop their CTL industry are still in place. The development certainly would not have taken place without them.

[pan1]

Synthetic fuel is possible, but currently forbiddingly expensive. Probably won't be cheap until electricity is virtually free.

High speed flight will therefore be a rare thing in a world without fossil fuels.

Zeppelins are certainly a possibility. Really very safe as long as you don't fill them with Hydrogen. Once we get a few fusion plants up and running Helium will be a by-product anyway.

[Rumor_Watkins]

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

[yabob]

OK, and Sasol:

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

[UncleNito]

One interim solution might be more and larger turboprop airliners. They burn a lot less fuel, and the speed penalty wouldn't make a huge difference in door-to-door time on trips of moderate length. Acoustic technology can probably overcome the noise issue; I think the Beech King Air already has an active noise-canceling system, although I don't know if it's practical to scale it up.

Also, the trend of the last 10-20 years has been toward smaller planes and more frequent flights. As fuel prices go up, it might begin to make sense to have fewer flights with larger aircraft. Widebodies first came into fashion during a fuel crisis, and regional jets became popular when fuel was dirt-cheap, although I don't know if there's a correlation there.

Longer-term, I'd love to see more high-speed regional rail with seamless integration with the air travel network. Downtown Indy to ORD, for example. I'd be all over that. That would be a sort of hybrid solution: not eliminating airliners, but replacing short connecting flights with rail.

[Zsofia]

Yeah, it would really be nice if you only flew coast to coast or international and took a high speed train for shorter trips - unless they fucked up the security like they have in aviation it would probably take less time when you come down to it.

[This_Just_In...]

At some point when most engines have switched to non-fossil fuel sources, the drop in demand will cause the oil prices to stabilize or even decline. Assuming there are cheaper alternatives, there is some price point that people the world over will not drive gasoline engines, and once the infrastructure is sufficiently modified there would be a lot less demand for oil. If gas was $30/gallon, would you drive a gas engine? Would you save up and pay 8 times more and still take the vacation flight to Hawaii? I certainly would not do the first but I would still fly occasionally I think (albeit less often).

There will always be some oil, even if it has to come from tar sands or even coal.
So probably airlines prices will rise a lot but stabilize at some point. Many airlines will fail and the remaining will cater to the smaller population that can afford flying. Maybe some super large global airline company will buy a chunk of northern Alberta and set up it's own oil production thereby crushing their competition.

[Ravenman]

Let's also recognize that government policy toward fossil fuels will also have a bearing for aviation. If there more alternative fuels able to be used for cars, trains, and whatever, it would make sense to save gasoline and diesel for transportation modes that don't have alternatives readily available.

In other words, the government could choose not to tax aviation gas, and tax the bejeezus out of car gas. Fewer people would use gas for cars, saving the fuel for planes.

[Chronos]

Zeppelins are certainly a possibility. Really very safe as long as you don't fill them with Hydrogen.

Hydrogen is safe, too. Zeppelins are safe no matter what they're filled with, as long as you don't coat the envelope with thermite. And no, I don't know what genius came up with the brilliant idea of using thermite-based sealant on the Hindenburg.

But to the OP, some of us think that high-speed rail is the future of "air travel".

[mnemosyne]

Originally Posted by UncleNito

One interim solution might be more and larger turboprop airliners. They burn a lot less fuel, and the speed penalty wouldn't make a huge difference in door-to-door time on trips of moderate length. Acoustic technology can probably overcome the noise issue; I think the Beech King Air already has an active noise-canceling system, although I don't know if it's practical to scale it up.

Bombardier markets the Dash-8's as Q400s (Q300s, Q200s also built, but only the Q400s are in production today), with the "Q" for "quiet". The newer generation of planes have Noise and Vibration Suppression systems which make the interior noise levels comparable to an typical jet, IIRC. The Q400 (DHC-8-400) is a 70-seater (68-78), and there is currently development for another stretch targeting the 90-100 seat range. The original DHC-8-100 sat 37 passengers, FWIW.

Given the expansion of the DHC-8, I'd say that noise cancelling systems do scale up quite well!

I also think turboprops are going to become increasingly common. The DHC-8 is Bombardier's money-maker right now, given as it flies at about 75% the max cruise speed of a comparable RJ, uses about 30% less fuel, and since the engines are mechanically simpler, has a much lower operating cost, and a passenger load of only about 30% is required to break even on a flight. The Q400 has a similar range to the CRJ900/1000 ERs, too.

I wouldn't be surprised if Bombardier and other airframe manufacturers aren't studying possible designs for future turboprops. They'd be crazy not to!

[Hari Seldon]

Although I would love to see high speed rail (or even medium speed rail), let me point out that hish-speed rail fares in Japan and France are expensive. I don't think they are cheaper than air, at least not now. Also I am not convinced that trains with diesel traction would even use that much less fuel than airplanes. If electricity can be generated without fossil fuels then electric traction makes a lot of sense. Incidentally, both the Shinkansen and TGV are electrified as are most trains in Europe.

I regularly take a train between Montreal and NYC. The distance is about 350 miles and if the train could average 60 MPH, it would traverse the distance in 6 hours. Add stops and an hour at customs (40 years ago the agents were on the train, so there was no holdup there) it should easily make it in 8 hours. Well, a year or so ago, they finally faced up to the fact that their ten hour schedule was a fiction and revised it to 11, but in fact it often takes 12.

[ivn1188]

Originally Posted by Chronos

Hydrogen is safe, too. Zeppelins are safe no matter what they're filled with, as long as you don't coat the envelope with thermite. And no, I don't know what genius came up with the brilliant idea of using thermite-based sealant on the Hindenburg.

But to the OP, some of us think that high-speed rail is the future of "air travel".

That hypothesis has been discredited by many sources. Hydrogen is flammable, and it takes a lot to make an airship float. It's by no means forbiddingly dangerous, but it's not like hydrogen is as safe as helium, fire-wise.

[Xema]

Originally Posted by pan1

Zeppelins are certainly a possibility.

On the transportation efficiency metric that matters most - passenger-miles per quantity of fuel - lighter-than-air craft are inherently poor. They are okay on fuel at low speed (and far better than any alternative when stopped) but then no one is getting much of anywhere. At the speed of even a moderately fast train, they are really quite bad (think about the energy required to push the necessarily huge amounts of of air out of the way).

By contrast, modern jet aircraft are surprisingly good. A fully loaded 747 can deliver something approaching 100 passenger-miles per gallon of fuel. The fact that it does this at high speeds is a considerable bonus. If fuel prices rise significantly, aircraft will probably slow down - at around 75% of current speeds fuel efficiency would be meaningfully higher. Of course, so would capital and crew costs per passenger-mile.

There's also the point that lighter-than-air craft are inherently flimsy and vulnerable to strong winds. Few large ones have had long careers. Barring some currently undreamed-of technical breakthrough, they are unlikely to play a significant role in transportation.

[Markxxx]

We also could simply go back to the days where people didn't fly much at all. If they took a trip it was for two weeks or they didn't go. You drove cross country, you took the train and it took three days. You didn't fly. You didn't go to San Francisco for two days. You went somewhere closer.

Think about it people in NYC would go to the Poconos or to Atlantic City or other short distances. Now they hop on a plane and fly to LA for the weekend or if they're really rich Paris.

High speed or even low speed rail isn't the answer to travel. It never was. The heyday of the railroads was from the 1870s to the 1920s. But even as soon as 1910 already railway lines and interurbans were going banktrupt on a routine basis.

Railroads for the average Joe, in various locations, couldn't compete in the '20s and they basically had a monopoly on transportation, they certainly couldn't do it today.

Without a population base that travels regularly (five times per day, twice per day) railways can't hope to make a go of it. Even now public transportation wouldn't make it without some government help.

Rail works in high density (that is the key, high density) areas only. Even in Chicago, the north side El Trains are packed compared to the red line south of the loop 'cause the density of the population on Chicago's North Side is so much greater, 'though the population of the South Side over all is much larger, it's spread out. So rail gets used less.

When I was a kid people died and you didn't hop on a plane and go to the funeral. You just sent your sympathy. Even if it was your mum or dad you didn't go. There wasn't time or it wasn't affordable. Immigrants came to this country and it was the norm to find out months after your parents died in the old country that they were actually dead. Now I know people who's father died and they all hoped on a plane and flew to Tanzania to bury him.

I'm not saying that's wrong, I'm saying that is a relatively new way of doing things. People will simply adjust to higher fares and will go closer places they can drive to, or do without. Businesses will do meetings by phone.

[John DiFool]

I wonder how super high-speed rail (c.f., a train in a vacuum-sealed tube, so no drag) will compete with hypersonic airliners, in about 50 year's time...

[Alex_Dubinsky]

Originally Posted by Zsofia

Yeah, it would really be nice if you only flew coast to coast or international and took a high speed train for shorter trips - unless they fucked up the security like they have in aviation it would probably take less time when you come down to it.

It's too bad the train system is all monopolies and vested powers. The principle of rail is very efficient, but because there isn't a highly competitive market the way there is for airlines, it doesn't translate into much real world gain.

[Alex_Dubinsky]

Besides, it's not like the whole cost of the ticket goes into fuel. A large chunk does. 25% of operating expenses go into fuel (as % of ticket it is less, considering margins). Maintenance, airports, etc., take money too. Even if fuel cost increases by a factor of 10, ticket prices will merely triple. Noone will be driving on $30 gas, but people will still be flying.