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Towards Silent Supersonic Planes
Roland Piquepaille writes "There is no longer a single commercial supersonic airplane since the retirement of the Concorde last year. And even during its years of glory, the Concorde was not a commercial success, mainly because it was not allowed to cruise at supersonic speed over land. Why? Because of the sonic 'boom' which arises when you break the sound barrier. Now, a joint program between NASA, the military and the aerospace industry wants to remove, or at least reduce, this sonic boom, by changing the shape of supersonic planes. It seems to work. After a 'nose job' on a Northrop Grumman F-5E, about a third of the pressure released when breaking the sound barrier has already been suppressed. This overview contains more details. It also includes a photograph of the modified Northrop Grumman F-5Ea aircraft flying off the wing of the F-15B research testbed aircraft. [Note: Previous results were reported here by Slashdot in last September.]"
Would it be possible to direct the sound of the "boom" upward so that nobody on the surface hears it?
How am I supposed to fit a pithy, relevant quote into 120 characters?
They've only been promising a solution to the Sonic Boom problem for, what, 30 years now?
Not only did the Concorde jump the gun by a few decades, I think it's hindered any development into the field of Commercial Supersonic Transport by being an noisy fuel-hog... Though it was one of the most beautiful planes ever built, right up there with the SR-71...
"If we let things terrify us, life will not be worth living."
- Seneca
Oh, com'on, the Sonic Boom was one of Guile's best moves.
But seriously, while this could be very cool for frequent travelers, I still think that even regular airplanes are too loud. Especially if you live relatively near an airport. Are any airplane manufacturers working on quieter sub-sonic planes?
[SIG] It's like putting a moose in the blender -- a recipe for disaster!
Takes 2 hours to get through the bloody airport and into the plane anyway.
Besides, whats the best we can do commercially? Mach 2 or 3 in the 'near' term (15-30 years). Big deal. Given the cost/benifit ratio I'm going to wager that we will be doing sub-orbital before we have air-breathing mach-3 flight.
Why? The amount of development required to develop 'quiet' and 'fuel efficient' supersonic craft vs. the level of technology already in existance for boosted flight. Leave the atmosphere and sound isn't an issue, and saves a lot of fuel as well; although spending an hour weightless is bound to upset a few tummies.
Either way, I am desperate to see some faster travel. 8 hours to Chicago from London 57 years after breaking the sound barrier and 35 years after landing on the moon is a sad commentary on the human condition at present.
As well as the Shuttle for Areas near Cape Canaveral...
But alas, no. The Concorde has a much higher 'figure of merit' (FM), and creates a much larger boom than a fighter. The size of the boom relates to the weight and length of the aircraft, and since the Concorde is much heavier than the relatively small Fighters...
The Concorde has an FM of 1.4, wheras most fighters have less than a 1... Translation: Concorde leaves a much bigger boom.
"If we let things terrify us, life will not be worth living."
- Seneca
...and a matter of peronal taste, but I think the XB-70A Valkyrie was sweeter than either Concorde or the SR-71.
... they were trying to drum up support from some newsies for a news short on TV, sort of free advertising. Playing the odds figuring so many reporters/broadcasters whatever were there, some one might have took an interest in it. My guess anyway, or someone back at SST headquarters sent them to the wrong show! Might have happened....
Of course, ya never know. I worked tradeshows for 15 years, I have seen some thoroughly weird stuff, and some incredible stuff that just disappeared, never heard of it again. One I remember though, it had to be that dean whassis his name with the segway, his earlier invention, the super wheelchair thing that could climb stairs, and was either voice activated or breath pulses activate, along with a normal joystick. Slickest thing ever, had a tiny cheap 10 foot backwall booth, just pipe and drape and a table, on a medical show, about the cheapest booth there and definetly the best tech on the show that I saw. Another time on a car show, lamborghini had a booth, this was before the explosion in giant SUVs, they had this incredible 4 wheel drive vehicle, with the v-12 engine in it that was in the countache, etc. Dang car was NICE, I mean, r-e-a-l nice, most plush and most rugged thing I ever saw for a passenger vehicle. Cheap old 20 foot of carpet, no booth, just the best vehicle in the show and a little sign on an easel said lamborghinni, that's it, they didn't need no blinken lights booth.
and don't get me going on booth babes.....
The concorde was a major money maker for BA, less so for Air France. The fuel costs were expensive but not unprofitably so. A standard 747 holds 300 people, most in cattle class. All seats on Concorde are first class.
The reason the plane failed economically was part due to the oil price shock hitting when Concorde entered service. A much bigger factor was Boeing lobbying to have Concorde banned from the main US airports, a piece of protectionism the US govt. went along with.
The Concorde consoirtium had the last laugh, these days it is known as Airbus and the Economist thinks it likely that Boeing will be out of the civil aviation business entirely in ten years time. In response to the US protectionism the EU underwrote development of Airbus. Boeing tried to respond with the idiotic 'fly by wire is dangerous FUD' and the rest is la historie. Boeing's current survival strategy is renting some very overpriced fuel tankers to the pentagon that meet far fewer of the original criteria set than the Airbus bid and cost about twice as much. But don't call that protectionism, its free enterprise.
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They train with the german airforce who has a number of soviet aircraft accuired before the unification of germany.
...Are cruise planes.
:)
/. reader with more physics knowledge tell me if this can/ cannot work?
There are lots of people that want to do New York- Paris in 1 hour, but most people I know aren't in that situation.
Maybe a blimp-like plane, that could transport transatlantic freight faster than a sea ship but at similar cost, or passengers on a leisurely voyage.
Fuel savings could make up for some of the extra costs. Better efficiency might appeal to the green crowd too.
Other advantages would include less jet-lag, and hopefully a more relaxing adventure.
And another one: terrorists aren't likely to send a blimp into a building at a stealthy 100kmh
Ok, can some
Information: "I want to be anthropomorphized"
The Concorde operation was profitable once they were purchased for a pound, or whatever it was. The fuel capacity of concorde was 96 tonnes and it carried around 100 passenger, each of whom paid about $10000 for return trip.
Fuel costs about $400 per tonne plus taxes.
You do the maths.
KnightStalker has it close enough; Fryguy is off by a lot. First let's talk about what a shock wave is. A shock wave is traditionally modeled as a discontinuity of pressure (in reality pressure steps down sharply over a small but finite length). A shock wave builds due to higher pressures 'downstream' trying to talk back 'upstream' but is physically impossible...that is, after all, the definition of the speed of sound; it is the rate at which pressure waves propogate through the medium. So as some point the 'high' pressure has to meet the 'low' pressure (all relative), and that is where the shock forms.
:) and it is believed that both the shocks and direct dumping of fuel exhaust (contaminants) at that altitude are very harmful to the atmosphere.
Taking the simpler case of a fully supersonic aircraft, a strong shock wave will form off of any surface that would cause a stagnation point in the flow: nose of plane, canopy, leading edge of wing and tails. There are many classic photos of F-14s with their shocks visible due to water vapor. Where are those shocks most visible? Nose/canopy and wing. The tail can also be a strong contributor especially in older aircraft. But in fact there are MANY other smaller/weaker shocks all over the aircraft (tails, antennaes, gaps in panels), but because they are weak, we don't tend to hear them distinctly.
So what this program is attempting to do is similar in thought to radar scattering. Rather than making one/two STRONG shocks (radar returns), but gently turning/blending the surfaces at critical points they can spread the shocks out, making more but smaller/weaker. And since energy dissipates as R^2, any weaking is magnified quickly.
And, btw, another problem with the Concorde (and Soviet Tu-144) was environmental. The aircraft cruised much higher than normal commercial craft (in the stratosphere....or one of those sphere's
Just my $0.03 worth.
And in the larger sense, what is the fuel efficiency delta between the quietest plane verses the most fuel efficient design possible.
Unless that delta is quite small, I'd say it ain't going to happen.
"It's the height of ridiculousness to say for those 9 lines you get hundreds of millions."
The reason it *failed* was because one leveled an apartment building when it crashed, and the other's seemed to have the same problems it had, maintenance/design-wise.
You may not realize this, but there are people, lots of people, who are both willing and able to pay $10,000 for a plane ticket, if only to get from London to New York in half the time. For some people (bankers, investors, musicians, models, movie stars, people of that nature), it actually makes damn good financial sense to pay that much extra for a ticket. When you make $10,000 for a 2 hour appearance, you can fit in 2 extra appearnces with that much time earning yourself an extra $10k.
Just because most people in the world can't buy a house that sells for $41 million dollars doesn't make it a failure in the real estate business. Someone out there can and will. It becomes a failure when one or two of the rooms cave in on the new owners, and no one wants to buy it from them.
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While I agree that Boeing did some bad things during the 1990s I can't help but notice that they did build the 777 wide body during that time and that airliner has sold very well and has had a good amount of backlog at their factory. It completed very well against Airbus' widebody twinjet the A330 and to some extent to A340. If Boeing hadn't built the 777 then Airbus would have gotten alot more widebody twinjet orders than they did.
The really interesting news along these lines is that Lockheed's Skunkworks is working on supersonic business jet. Its rumored that Warren Buffet is behind it.
For those that don't know, Bershire Hathaway owns Netjets, the largest purchaser of business jets.
It wasn't really because there were originally problems with flying over land - the American aerospace lobby were so threatened by the fact that the Brits/France had manged to do something that they'd been spending serious amounts of money on that managed to stir up US environmentalists to the point where they managed to *get* Concorde banned from flying over land!
There, that ought to put the cat amongst the pigeons!