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Son of Concorde
targo writes "BBC reports that EADS is considering a new generation hypersonic commercial aircraft. "Son of Concorde" would be twice as fast, carry twice as many passengers while being much quieter than its predecessor. It would get from Tokyo to Paris in just two hours, US destinations are not mentioned.
However, as Japan's failure last summer suggests, it might not happen too easily."
2 hours to cover half the world... It almost sounds like a low-earth-orbit travel arc.
This sounds like aeronautical vaporware. Boeing's attempt at a higher-speed "Sonic Cruiser" was scrapped last year when the company felt that economical flight at current speeds was the way to go (via the 7E7 project), and the Cruiser wasn't even planning to pass the sound barrier.
It's one thing for EADS to think speed is the way to go, and it's quite another to propose something as ambitious as they have. Based on the article I strongly suspect they're making token research into engine tech but aren't actually trying to design a plane at all here (no mention of fuselage design at all). It's just Fun with Public Relations.
And because of that they dont have to server dinner. Pretty sneaky!
One line blog. I hear that they're called Twitters now.
Until very recently every plane that flew above Mach 1 had to do it while on afterburners, but I believe the new F-22 Raptor can fly at "super cruise" which is some method of breaking the sound barrier without afterburners, which saves a huge amount of fuel. Last I checked the technology behind that was still secret.
I question whether this proposed airplane will actually fly in the hypersonic region, since to an engineer that means Mach 5 or above. If it can actually make the Tokyo-Paris flight in 2 hours, you could spend a day in Tokyo, fly to Paris, get a night's sleep and live the day all over again in the land of love!
Er, no. Concorde flew above 60,000 feet, where air resistance is much less than the customary 35,000 feet. Concorde was just as a fuel-efficient cruiser as subsonic planes; trouble is, it sucked 25% of it's fuel on take-off...
I disagree. Flying halfway around the world is a PITA, even at the fast-ish speeds the current crop of jet-liners can fly at.
Go to any international airport and take a look at the travellers who have spent 12 hours on a flight, with 8 more ahead of them after their stopover.
Trust me on this - if they have the money, people will pay for this high-speed service. Even if it means an "economy" seat for the price of business class, it's worth it to shave 15 hours off your travel time.
Forget thrust, drag, lift and weight. Airplanes fly because of money.
I think Europe to Japan is a North Pole route, so it's a lot shorter then it sounds.
Much as I love Really Fast things, the enviromental effects will be the big hurdel, not noise.
And the best thing about a Polar route? - There's none of that pesky Ozone to get in the way of your hyper-speed aero-plane.
Moneyed corporations, non-working 'poor' and criminal prisoners are turning productive citizens into tax-slaves.
Supercruise is a fairly easy-to-understand phenomenon; in effect, it requires two things:
- lots of thrust from the powerplant;
- subsonic airflow in high quantities through the engine due to the way a "conventional" turbine operates, with slightly supersonic exhaust flows.
Normally, a turbine can't attain supercruise because of the latter; the airflow needs to be slowed considerably going through the powerplant in order to stop a shock stall (where the supersonic shockwave suffocates the powerplant).The powerplant behind the F-22 (Pratt&Whitney F119-PW-200) attains this primarily though a few good engineering tricks such as single-crystal-cast blades with a slightly shallower angle of attack than most; thus allowing the engine to operate at a higher temperature and pressure internally than is "normal". It has a lower bypass ratio (the ratio of cool air passing around the engine to that going through the engine) than most fighter-class engines; thus, it needs a smaller front fan, which in turn reduces the area causing a shock stall. It also wears out quicker, but that's another matter entirely. :)
High bypass ratios are great for fuel efficiency at subsonic speeds, but by virtue of the way these turbines work and their tendency to shock-stall when confronted with a supersonic airflow, are not much good for supersonic flight, and not for the nearly-supersonic airflows that supercruise requires.
A typical mid-to-high bypass turbine used in a fighter will have a bleed air system to reduce the airspeed running through the turbine; this has to be counteracted by dumping raw fuel into the bypass & exhaust (i.e. afterburner). Indeed, to get much over M1.0 the F22 needs to employ this same trick. A low bypass turbine can operate with input airspeeds closer to M1.0, which in turn means less air needs to be bled, while still producing a slightly supersonic exhaust out the rear end.
As I read /. I am struck by the persistence of people saying:
* This can't be done!
* This can't be done economically!
* We shouldn't try because it can't be done.
I just hope the people working on making a plane that will cut down on my travel time have a different attitude. I hope they are asking how can it be done? rather than why can't it be done.
It's easy to be a nay sayer. Nothing exposes genius faster than naysayers proven wrong.
-- $G
It appears the Beeb has confused peak speed with average speed.
According to the US Department of Agriculture, the Great Circle distance from Paris to Tokyo is 6033 miles. Let's round that to 6000 mi. The speed of sound varies with temperature, but using 750mph makes the math easy (at aircraft altitudes, the speed of sound is closer to 700mph).
If it could hold the fuel, the Concorde at Mach 2 (1500mph) could do 6000 miles in four hours. If the EADS jet achieves Mach 4 (3000mph), it could do 6000 miles in two hours. If the entire distance were covered at cruising speed.
My impression (purely from being a passenger) is that it takes half an hour or so for a typical commercial airliner on a 1000 mile flight to reach cruising speed and altitude; the plane will then be at cruising speed for about 60 minutes, and then another 30 minutes is spent in deceleration. Of the 2 hours spent in the air, only half of the time is actually spent at crusing speed.
How long would it take for the EADS-SS to reach Mach 4? And how long would it take it to slow down from that speed to the typical 150mph (+/-) landing speed that current runways are designed for? I doubt the typical passenger is prepared for Michael Schumacher / John Force g-forces on takeoff and landing.
Let's say the EADS-SS takes 45 minutes to reach Mach 4, and another 45 minutes to drop back to landing speeds. Assuming linear acceleration and deceleration, that's an hour and a half spent at an average speed of 1500mph. So 2250 miles of the trip takes 1.5 hours. Transiting the remaining 3750 miles at Mach 4 (3000mph) would take another 1.25 hours, for a total trip of 2.75 hours. [Ignoring any ground taxi times or other delays.]
I would think, fuel-wise (which is basically the only marginal cost of airplane flight), that going from Mach 2 to Mach 4 is more expensive than going from Mach 1 to Mach 2. On the other hand, Mach 1 -> 2 is done in denser air than Mach 2 -> 4, so maybe not.
This could be a great question for a final exam in Engineering Analysis and Synthesis.
Concorde didn't use its afterburners while cruising.
http://www.concordesst.com/powerplant.html
Perhaps you should think before you post?
not quite. I work for an airline. A positively giddy amount of work goes into flight planning. Shortest path comes into it if you're trying to be quicker, but these days fuel burn and thus cost matters a lot. Trying to maximize your tailwind, reduce headwind, avoiding restricted airspace and following airways (like an interstate in the sky) for air traffic control reasons. This might answer the "hops" you talk about. Its navigational beacons which are often at airports.
Which brings us to tracking. If you're over the open ocean you follow tracks. Its a bit like hunt for red october going through the canyons. This speed, at this altitude through these points to maintain separation. Over land, you can be spotted within a couple hundred miles by your ground-air comms. And theres a lot of those. You are almost right on the airports, depending on where you're flying, type of aircraft and and how many engines you must be within a certain flying time of a suitable airport. Its called ETOPS.
So lots of things to worry about, including weather, but it typically starts with shortest distance.
By going with a smaller aircraft, Learjet sized, you can reduce design and manufacturing costs. That and you can target the filthy-rich-let's-buy-a-trip-on-a-Soyuz-for-fun market instead of the save-bucks-at-all-costs airline market.
Once a few supersonic bizjets are on the market, it would be easier to scale the designs up to airliner sizes.
Meldroc, Waster of Electrons