France and Japan Planning New Supersonic Jet

jonerik writes "According to this article from the Associated Press, Japan and France are cooperating on research to produce a supersonic passenger plane that would be able to carry 300 passengers (three times as many as the Concorde) and fly from New York City to Tokyo in a mere six hours. Current plans are for the plane to be able to cruise at mach 2.4 while reducing the noise and high fuel consumption associated with the Concorde during its years of service. Although Japan had previously done extensive research towards building a 250-person mach 1.6 passenger jet, the agreement with France - announced at the annual Paris Air Show on Tuesday - represents a interesting shift in technological alliances given the Japanese aviation industry's longstanding ties to the United States. 'To research closely in this area with the Europeans does represent something new,' said Yoshio Watanabe, an official with The Society of Japanese Aerospace Companies, which is heading the new initiative on the Japanese side."

Comments

Does it represent a shift?

[wa1ter]

represents a interesting shift in technological alliances given the Japanese aviation industry's longstanding ties to the United States

Does it really or are they just trying to benefit from France's experiences with the concorde for this project?
Nowhere in the article does it say it'll change it's alliance for anything else.

Re:Engine Noise?

[DeathFlame]

Bing Bing Bing! We have a wrong answer!

Sonic boom is tottaly due to pressure waves created by going faster than the speed of sound.

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

Re:Engine Noise?

[Anonymous Coward]

Here is the flight path from New York to Tokyo:

http://gc.kls2.com/cgi-bin/gcmap?PATH=jfk-tyo

Re:Engine Noise?

[DeathFlame]

From http://en.wikipedia.org/wiki/Sonic_boom

In the late 1950s when SST designs were being actively pursued it was thought that although the boom would be very large, they could avoid problems by flying higher. This premise was proven false when the North American B-70 Valkyrie started flying and it was found that the boom was a very real problem even at 70,000ft (21,000m). It was during these tests that the N-wave was first characterized.

Re:That's because....

[MichaelSmith]

The FAA prohibits supersoinc flight over US Soil @ any altitude without prior special approval

Above 100km altitude is OK because that is in space.

Re:Engine Noise?

[justine_avalanche]

The article's not refering to the sonic boom (usually happens above the ocean anyway), but to the actual engine noise.
The concorde had the loudest engine around, and I think it was a problem for most airport noise regulation.

Re:2015? MAN....

[hazee]

Umm, remember that Concorde was designed in the 60s, and it's *still* the best commercial supersonic aircraft to date.

Jumbos from the same era still fill the skies too.

Advances in aviation don't happen as fast as you seem to think.

Re:Supersonic workaround

[VoidWraith]

Except that 3 is irrelevant, for the fact that the flight path looks like this: http://gc.kls2.com/cgi-bin/gcmap?PATH=jfk-tyo (thanks to an earlier poster).

Re:Engine Noise?

[WolfWithoutAClause]

The great circle route would be used (approximately) ignoring any small deviations for winds etc. Picture is here

Looks like it goes right through Canada, quite a bit of America, and China(?)

Re:Don't forget the other factors

[kabz]

Yep, and for a *really* large vodka, fly Avianca, the Venezuelan airline.

Oh, a voddy poured by one of the worlds most beautiful women ;-)

Re:That's because....

[Zebra_X]

Not true. Actually the FAA is responsible for enforcing the National Environmental Policy Act of 1969. This act protects the "quality of the human environemt". The U.S. is unique in this regard because I don't think many other countries have such legislation.

The bottom line of the FAA directive however, states that "no measureable sonic boom overpressure" may reach the surface of the U.S. except within an authorized test area. There is a rather lengthy procedure to be granted such an authorization.

The thing is

[Sycraft-fu]

Supersonic jets in the past used real jets, not turbofans, afterburners if you like. Basically just burning raw jet fuel and using the hot gas to accelerate the plane. Fast, but VERY inefficient. Normal jets get theri efficiency from their turbofan engines.

Now these days It is possible in theory. The FA-22 has engines that can go supersonic on turbofan, but I don't know that they'd pull Mach 2 (I dunno how fast they can go on TF before they need to go burner). Also just because they can make a small fighter do it does not mean they can make a large passenger jet.

If the jet is a real jet engine it'll be fairly noisy and not very efficient as compared to the new Boeing and Airbus offerings.

So it really depends on what kind of implementation they can get. If they make a jet that's all turbofan, and can do efficient subsonic flight then ya, might be a winner. If it's just a new Concorde I'mm betting costs will be prohibitive, and noise a major problem.

Re:The thing is

[be-fan]

There is a reason turbofans aren't used on mach 2+ aircraft. The basic problem is that in order to operate a turbofan at supersonic speeds, you have to use an engine inlet that uses a shock wave (or a series of shock waves) to slow down the flow to subsonic speeds before it hits the fan blade. Fans, like all propellors, drastically lose efficiency as the incoming flow approaches supersonic speeds. This design causes the loss of some energy, so at a certain point, a turbojet actually becomes more efficient than a turbofan.

Re:The thing is

[be-fan]

Not quite true - the engines for the F-22 Raptor are F119 Turbofans (http://www.pratt-whitney.com/prod_mil_f119.asp)
which enable the aircraft to achieve supersonic flight without afterburner (quite an achievement).

It's completely true. I didn't say you couldn't have turbofans that operated at supersonic speeds. I said that turbofans:

a) cannot reach really high supersonic speeds
b) are less efficient than turbojets at some mach number

This is all the result of the fact that airflow through the fan must be kept subsonic, or else there is a drastic loss of efficiency. If you look at supersonic turbofans like on the F-22, you'll notice the intakes I mentioned that slow down the flow to subsonic speeds before the air hits the fan blades.

A turbofan and turbojet are both turbine engines with a set of fan blades as the first thing the incoming air "sees" after the inlet. These aren't like propeller blades

Turbojets have no fan, they just have a compressor before the combustor. And the solidity ratio doesn't make that much of a difference, fans can be treated using the same theory as propellors. Like propellors, they suffer a drastic loss of thrust as the incoming air approaches sonic speeds.

Your description of turbofans versus turbojets is correct, but you have to consider why turbofans are more efficient. Basically, it's a result of the following two equations describing the jet exhaust:

Thrust = mass-flow-rate * velocity
Kinetic energy = 1/2 mass-flow-rate * velocity^2

As you can see, thrust increases linearly with both thrust and velocity, but the kinetic energy of the air increases quadratically with velocity and only linearly with mass. Any kinetic energy imparted into the exhaust air is basically wasted from the engine's point of view, so its desirable to minimize this residual energy. As you can see, you can double thrust by either doubling the mass-flow-rate or doubling the velocity. Both give you the same thrust, but the latter approach leaves twice as much residual energy in the exhaust.

Turbofans work on the principle of maximizing mass flow rate and minimizing exhaust velocity. Instead of moving a little bit of air at high speed through the core, they extract most of that core energy at the turbine, and use it to drive a fan that moves a lot of air at low speed through the bypass ducts. The result of this is that in a high-bypass ratio turbofan, the fan provides the vast majority of your thrust.

Now, it becomes obvious why turbofans don't work well at high supersonic speeds. The closer the flow through the fan gets to sonic, the less efficient the fan becomes at providing thrust. Since the fan provides most of the thrust of the engine, the engine suffers a drastic thrust loss.

Re:Engine Noise?

[be-fan]

Completely wrong. What event horizon?

Shockwaves are caused by an object moving through a fluid faster than the speed of sound (ie: the speed of pressure wave propagation in the fluid). At subsonic speeds, pressure waves bouncing back from an object affect the incoming flow, basically "warning" it of the existance of the object. That's how the fluid can flow smoothly around the object --- the pressure waves caused the fluid's path to change long before it hit the object. At supersonic velocities, the pressure waves don't move fast enough to affect the incoming flow. So the fluid cannot flow smoothly around the object, and a shock wave is created where the fluid has to instantaneously react to the presence of the object.

Re:That's because....

[follower_of_christ]

Planes launch horizontally and ICBMs launch vertically. ICBMs follow more of a ballistic flight pattern when they are in the atmosphere, planes.... turn. Planes don't leave the atmosphere. The ICBM would have to re-enter the atmosphere and recorrect its descent and begin traveling at the same altitude as a supersonic jet.

That missile better have some very sophisticated Atificial Intelligence and be on a registered flight pattern because we'll be trying to communicate with it if it isn't and before it even gets close we'd probably scramble jets before it crossed any of our borders if its not telling us with a human voice what it is. There aren't any non-military supersonic jets in service currently so a single supersonic object floating around will be very closely monitored.

Laws of Physics

[EddyKilowatt]

SST's get re-studied every decade or so. Boeing and Douglas (remember them) last took their turn in the 80's, courtesy NASA funds. Gulfstream and one of the Russian design houses got far down the road toward a supersonic bizjet in the 90s. Now it is Japan's turn. They all run into the same laws of physics, and the same laws of economics. Until there's a breakthrough in engines, structures, fuels, or aerodynamics (or perhaps all four), don't look for an SST anytime in the next decade or two. An SST could be built today, even without breakthroughs, but it wouldn't make anybody any money. The laws of physics guarantee that the planes are exotic (skin temperature hot enough to boil water), thirsty (inefficient supersonic wing lift), and noisy (sonic boom = flight routes over land very restricted). These factors all add up to expensive tickets, and the market studies (including the one called Concorde) all show that the market isn't there. And that's not even beginning to take environmental concerns into account, such as high-altitude ozone depletion and of course greenhouse gas emissions.

Re:Japan and France

[El Cabri]

The EU was the one that would be negotiating at the international level from the start. The French bid first disputed a primary within the EU against a Spanish proposal for who would host ITER if awarded to the EU. After the Spanish retracted their bid the French project officially became the EU proposition.

Re:interesting

[zippthorne]

Um.. you test engines in wind tunnels. Hypersonic wind tunnels are really hard to come by. There's one at Glenn Research Center near Cleveland, Ohio. They have a "moveable wall" to dial up different mach numbers for various projects made of inch and a half thick steel. It is one of the largest tunnels of its kind (very few are actually walk-in tunnels) but the usefull stream is probably very close to the size of the engine to be tested. I am unsure of what it's maximum mach number is, but it's definately single digit.

You start out by testing the engine at low speeds, and keep increasing speed until you notice some vibration mode that you didn't find before or you reach the limits of the materials you chose for initial testing. (like maybe you didn't wait for the blades to crystalize, but you're not using maximum engine stress so it cut fab time for the prototype) or any of a number of pre-defined stop points at which you evaluate the condition of the engine and either proceed with more testing or scrap and redesign. It seems they haven't tested it at its design speed yet.

Re:internet has obsoleted the necessity for contac

[tsotha]

The internet/voip and other communication mediums have obsoleted the necessity for face to face contact and the costs associated with business travel. This is why (at least in the US) airlines are going bankrupt every single year. Only southwest manages to survive, but that's because they are like the walmart of the skies.

That's just plain wrong. Last year, 2004, saw the greatest number of passenger miles flown in history. The terrorist attacks of 2001 hurt the entire industry, but that only sped up the inevitable. The simple fact is Southwest and similar carriers are eating everyone else's lunch - the large incumbent carriers are saddled with inefficient systems and expensive union contracts, so they just can't compete.

Yes, they were loud

[tkrotchko]

I remember in the 80's and early 90's when they would regularly fly in and out of Dulles airport. I lived between DC and Baltimore and you could hear those things coming for minutes before they got there and minutes after they left. It was very distinctive.

The only thing louder is/was when military fighter craft were patrolling right on and after 9/11.

The Concorde was *loud*.

Memories of the Concorde

[Beatlebum]

I hope the project is successful, however, if it doesn't get buy-in from the beginning it could suffer the same fate as Concorde. Although Concorde was a technical marvel, the U.S. did everything it could to scuttle the project, for example, its flight certificate was delayed by the FAA until it was sure the project was busted. The premise of Concorde was fast trans-atlantic flight, but its first scheduled route was Heathrow to Bahrain because countries followed the U.S. and refused flight certificates. By the time the U.S. did grant a heavily restricted certification the lack of orders had made continued manufacture untenable. It's quite ironic that the U.S. refused certification on environmental grounds.

I'm sure there will be the usual Concorde counter-arguments posted here, some of them are true. It's true that it was a fuel hog and it's true that it was noisy. But if 500 were built instead of just 16 supersonic flight would have become much cheaper. With only 16 all parts were custom built and very expensive. Heck the Concorde has more in common with the SR-71 than a 737. It boggles the mind to think that it cruised faster than an F-18's top speed.

My father worked on the project from the beginning, for those interested here's a link to a couple of photos he took when Concorde 002 made its maiden flight-

http://latte.com/gallery/Concorde-002-First-Flight

Re:Memories of the Concorde

[amabbi]

The first flight of the PROTOTYPE Concorde was in 1969. After test flights, modifications were made to the design. The rollout of the first PRODUCTION version of the Concorde was January 31, 1975. This, incidentally, was the aircraft that crashed in 2000.

Thus, your assertion that there was a 6+ year delay due to US certification issues is warrantless. THIS IS FACT.

Furthermore, once the US did certify Concorde flights in 1976 and 77, why did the airlines then order the aircraft? Because it was too expensive to operate, and used far too much fuel at a time when fuel was scarce due to the Arab oil embargo.

Re:2015? MAN....

[calidoscope]

Consider the CF6-50 (old 747-200 engine). It's fuel consumption at cruise (35,000 feet and mach 0.8-ish) is about 0.62 pounds of fuel per pound of thrust per hour. The Concorde engine's consumption at cruise (53,000 feet at mach 2.0) is 1.19 pounds of fuel per pound of thrust per hour. Now, consider that during supersonic cruise, your drag skyrockets by a factor of 2-3. So not only are you using 2x as much fuel for a given level of thrust, but your thrust needs to be twice as high to keep the plane flying!

If the L/D remains the same, then using twice as much fuel per hour to go twice as fast results in the same fuel consumption per mile or kilometer. You are correct in that the L/D is 2-3X lower for a supersonic aircraft.

Engine technology has advanced a bit more than you suggested, especially for supersonic aircraft. Chief example is the F-22 that can fly supersonic without afterburner.

I'm wondering if going to Mach 2.4 is a good idea compared to Mach 1.6. At M1.6, it is possible to get almost isentropic conversion from supersonic flow to subsonic flow with multiple oblique shock waves - which would do wonders for engine performance - now if there was a way of improving L/D.

Another example of gas turbine progress - an early 1950's 4500HP GE gas turbine had a thermal efficiency of ~18%, the latest H series turbines from GE have a 46% thermal efficiency.

Re:That's because....

[Anonymous Coward]

Now that's rich! The US forbid supersonic flight over their own territory while sonic booms from USAF fighter planes were a common occurance in germany in the 80s!

Re:Measurements

[Anonymous Coward]

Vietnam. Yep. We got sucked into that one by the French. Should have stayed out of that one. Or, at least not fought it as a damned police action. The only time we were on track was when we took the war home to the NVA.

In virtually every major action the coalition forces (yes there were other folks there, except the French who had gone home, besides the US) beat the NVA on the battlefield. It was Jane Fonda and her ilk who undermined domestic support that caused politicians to fear being tossed out of office that finally drove the US out of 'Nam.

That, by the way, is very probably what will happen in Iraq. While the US (and non-combatent Iraqi) losses seem high, by 'Nam standards they are pretty low. We were seeing hundreds of casaulties, on all sides, a day back then.

Re:Engine Noise?

[nospmiS remoH]

Your wrong :). The sonic boom is from the shockwave created when the aircraft is going faster than the speed of sound (> Mach 1). Think of the shockwave as a cone with the point at the nose of the aircraft. That cone expands outward like, well, a cone. Where that cone intersects the ground, that is a sonic boom. Here is a good description

Re:Measurements

[Anonymous Coward]

Being British I shouldn't do this but I can't help it:

WW I - France on winning side
WWII - France on winning side (both actually :-)
Korea - Odd definition of win, I'd say a draw at best
Gulf War 1 - France on winning side again
"The First Persian Gulf War,. Jan.-Feb., 1991, was an armed conflict between Iraq and a coalition of 32 nations including the United States, Britain, Egypt, France, and Saudi Arabia."

Re:Little people

[rvega]

According to Wikipedia, the French are taller, on average, than Americans (67.15" vs. 66.85", assuming a 50/50 male/female split). You're right about the Japanese, though: At 5'9", I never felt like a big person until I spent some time on Tokyo trains. I never felt that way in France.

For bigger planes, we'd be better off having them designed by the Dutch. Whatever happened to Fokker, anyway?