Paul Jen asked:
Love your show; listen to it on podcast. Also thank you for answering a few of my questions in the past (survival time in sealed car, coughing while cleaning ear).
I was on an interminable flight from New York to Hong Kong a few days ago, and I don't understand why are Boeing and Airbus not working on increasing the speed of air travel? They have worked hard to improve the seat comfort, entertainment and food, but heck, if they just shortened the trip by 50% that would please me 500%. Are we going to be forever stuck in this air speed? What are the constraints of aerodynamics? Are noise rules the issue? Can a supersonic jet be ever built with "decent" fuel economy? Will we ever see another "Concorde" in our lifetime?
Sara - This week, we buckle our seat belts ready for takeoff with this question from listener, Paul Jenn.
Paul - I was on an interminable flight from New York to Hong Kong a few days ago and I don't understand why airplane manufacturers arenít working on increasing the speed of air travel.
Sara - So, why can't we fly just a little bit faster? Is it a case of better design and engineering or will we be stuck at this slow speed forever? Well, weíre off to a flying start as Neil Scott, head
of engineering at Airbus shot back fast with this answer...
Neil - In short, speed costs fuel and money. If you're driving your car at 40-mile an hour and then accelerate to 80 miles an hour, what happens to fuel consumption? It goes up. The same is true on an aircraft. The faster you go, the more fuel you burn. Drag, which causes the increase of fuel burn, is actually proportional to the square of the speed [addendum: energy to overcome drag is proportional to the cube of the speed]. So, drag increases at a faster rate than increasing speed. So, you can't just get there more quickly, you have to pay for it. One of the biggest costs for an airline of course is fuel, therefore the likelihood of us designing a supersonic aircraft for major commercial flying is probably not going to happen anytime soon.
Sara - Basically, more speed means more air resistance, means that cheap holiday flight you were planning on booking wonít be so cheap anymore.
Neil - Another advantage of decreasing fuel burn of course, is there's less CO2 emissions, less nitrous oxide emissions and less noise, so we all win.
Sara - Well, itís good to hear that we all benefit from flying slower, but is it a flight fancy to think I wonít be stuck in the air for 13 hours at a time as a jet setting grandma?
Neil - At the moment, itís not possible to build a super efficient plane that's also super speedy and cost-efficient. But with future innovations in propulsion systems, thatís engines, based for example on hydrogen or electricity, it might well be possible in the future.
Sara - Thanks, Neil. Maybe someday then. In the meantime Paul, maybe try to get some shuteye on the redeye. For next week, Matthew Boniface wrote in this yawn first of a question...
Matthew - Why do I yawn and why do cats yawn and can I catch a yawn from a cat?
Sara - What do you think?
Law of diminishing returns applies to making aircraft go faster...
Yes, but this can be solved by flying higher, which is what Concorde did. I generally agree though, we have not got the technology yet to both speed up the flights AND make it cheaper. graham.d, Tue, 17th Jun 2008
The Boeing 7E7, which eventually emerged as the 787, was originally planned to be a highly area-ruled design, capable of flying at just below the speed of sound for the same fuel burn as the then current range of airliners. However, this aspect of the design was eventually dropped in favour of flying at the same speeds as other airliners, but with reduced fuel costs, the main reason being that the airline businesses could charge the same price for the same journey time at a reduced fuel cost to themselves. Reducing the journey time would have seen the same fuel costs - guess which option was most attractive to the airline businesses?
yeah i would imagine it being really expensive and polluting and if its too fast it may give people heart attacks so there may be a speed limit for a aeroplane to be able to made up to benep, Tue, 17th Jun 2008
Aiplanes at present flying altitude have reached the maximum efficieny level. As can be seen be the abadoned Concord.
One version of this "soon to be revealed" project died in 1988.
Air travel gets slower and slower the time actually spent in the aircraft is often about half the of the actual journey time syhprum, Tue, 25th Nov 2014
If you've time to spare, go by air.
The next step may be sub-orbital rocket-assisted space hops.
Even if we get suborbital flights that can reach anywhere on Earth in a few hours (most of which is spent getting the last 50km through the atmosphere), there is still the jet lag, which is sometimes quoted as 1 day elapsed time to fully recover from each hour of timezone change. evan_au, Wed, 26th Nov 2014
I suppose you could minimize your jet lag by flying from Britain to South Africa, or Australia to Korea. Just choose your destinations carefully.
I think airline pilots gain brownie points for saving fuel and often fly the aircraft much slower than the technology alows syhprum, Sat, 29th Nov 2014
The object of airline flying is to meet a schedule: missing a landing slot can be very expensive and screws up everyone else's day too. Private pilots and bush pilots on the other hand tend to fly for maximum range. The speed you fly, in either case, depends on the expected wind vector. Flying slowly is rarely the answer unless you have a hell of a tailwind. You can reduce your fuel consumption to "idle" but in the case of a small piston engine you may end up going backwards (it's quite good fun in a Piper Cub), and in the case of a jet the burn rate at stall speed can actually be higher than the cruise consumption.
The following isn't much help for crossing oceans, but on all other paths it would be better to use a system like the hyperloop - maglev capsules running through vacuum tubes on a narrow track. Faster than planes and environmentally friendly too. David Cooper, Sat, 29th Nov 2014
High speed rail is already being used in many places around the world, except in the USA.
A Moscow to Beijing and on to Alaska high speed rail line is already in the planning stage and will get built if wars don't intervene syhprum, Sun, 30th Nov 2014
The time has changed! http://robbreport.com/aviation/airbus-joins-aerion-develop-as2-supersonic-business-jet http://edition.cnn.com/2014/09/24/travel/airbus-supersonic-jet/ Christophe B, Mon, 1st Dec 2014
Planes are now about as good as the best cars for pollution put out per mile, but there's greater potential for cars to improve. Planes also enable people to make lots of unnecessary trips that they simply wouldn't do by car, so the pollution goes up an up. There are a few people who do need to travel around more than the norm, of course (you may be one of them), and they can justify that travel as it is necessary and of benefit to all, but we need to eliminate unnecessary travel. We also need to free people up by eliminating unnecessary work so that they have more time to travel and can get places without needing to go so fast so that they can do it in much less polluting ways than using cars, planes or conventional high-speed trains. David Cooper, Tue, 2nd Dec 2014
Air travel is essential for environmentalists to attend conferences on pollution. Along with politicians, they have a neolithic intellect and are unable to use Skype. And if it were not for conferences on pollution, we wouldn't be able to exempt the major polluters (India and China) from abiding by the rules they make for everyone else. Apparently it is terribly important for people of limited brain power only to talk when the sun is within 60 degrees of the zenith, so they all have to be in the same place at the same time (with a break for lunch - the middle 30 degrees has some primitive religious significance). I've just been hearing about a 2-day conference of 5000 people in Sydney. Everyone went to dinner with their usual five friends and of course nothing was decided: 5000 environmentalists = 5000! (it's an astonishingly big number) arguments. You can't do that without aeroplanes.
Planes are essential so that environmentalists, politicians, and other highly paid saviours of the planet who are unable to use the telephone, can gather in one place in such numbers that they cannot make a decision.
Cars also enable people to make lots of unnecessary trips that they simply wouldn't do by foot or horseback. And there are many trips that people do in cars that would be better to do on foot or by bike. CliffordK, Wed, 3rd Dec 2014
Unnecessary air travel is only undertaken by primitive people like politicians and environmentalists, who are unable to use a telephone and cannot communicate unless they are all in the same place. So they travel to huge conferences involving too many people to actually make a decision, apart from exempting the worst polluters from complying with their wishes. I've just been hearing about a 2-day environment conference in Sydney involving 5000 delegates from around the world, who achieved absolutely nothing by being there.
Most conferences are a waste of time - there's no point in going anywhere to hear a speaker, and while small group discussions are more productive, they lend themselves well to video conferencing.
It's a good read and I think the most telling part is the fuel consumption panel. Concorde operated at 17 passenger miles per gallon, about a quarter of the efficiency of a small Cessna, whilst a 747 (or Airbus 380) flies at over 100 passenger miles per gallon, competitive with a diesel car and far less environmetal impact than road or rail travel.