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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.]"
If we could only do something about my neighbour's pounding stereo.
The dangers of knowledge trigger emotional distress in human beings.
The concorde was EXTREMELY expensive to operate, so even if it was allowed to travel supersonic anywhere it wanted, it still would have failed. airlines are cutting every cost possible in an effort to undercut each other, so the concorde's death was just waiting to happen.
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
Nope. The Boom is omnidirectional. In fact, the downward part of the wave is aided by the increasing atmospheric pressure.
"If we let things terrify us, life will not be worth living."
- Seneca
There was a smaller article like this in Popular Science a while back, and since I am very interested in planes and aerospace, it now is on my wall. I'll type it down for you guys, I'ts actually very interesting...
All Zoom, No Boom
Teaching an F-5E Tiger how to tiptoes.
There's nothing more dramatic than a supersonic jet streaking overhead; and nothing more annoying than the bone-rattling sonic boom it leaves behind. The boom really consists of two bangs caused by the N-wave in the planes wake, with rapid pressure rises corresponding to the nose and tail. Northrop-Grumman hopes that by tailoring a F-5E Tiger with a longer nose an modified tail, and tinkering wiht its body and wngs, the boom can be transformed into a smooth, inaudible hump. Engineers got the idea from research that goes back to the 1970's. Today's computers, which make it possible to model airflows up to 200 yards from a plane, were required to put the theories into practice. Tests being next august. --Written by Bill Sweetman.
I don't know exactly when it was published, but it shows that this is really no new idea. On an interesting side-note, my uncle worked for McDonald Douglas before they were bought out by Boeing, and actually was a systems engineer for the Coherent Readar systems for the F-5F. When I told him about this he thought it was one of the coolest things he'd ever heard.
~I was playing poker with tarot cards the other night. I got a full house and that same night five people died. True story.
Sure, the sonic boom wasn't too good, but that never stopped the US Air Force from flying their supersonic planes day in and day out over populated areas. I still remember periodic sonic booms over Tucson (from a nearby base) as well as over Seattle whenever Boeing was testing their latest SS jet fighter.
Let's face it, the main reason the Concorde wasn't allowed to fly over the US is because it wasn't US made.
Most supersonic aircraft require afterburners in order to go faster then sound, and afterburners are incredibly voracious consumers of fuel. I think that one of the other very important innovations is the "Supercruise" ability, seen on aircraft like the F-22 Raptor. This allows the aircraft to maintain supersonic speed for extended periods of time in a low power setting, and this in turn is just as vital for cheap, commercially viable flights. I hope that advances in sonic boom suppression will also work well with the necessary designs for supercruising, and that we may all be able to take advantage of such flights within the next 2-3 decades. If both aren't taken into account, and designers come up with plans that make for an either-or choice, it could mean supersonic planes will still be relegated to the relatively wealthy.
The short answer is "yes"
.The long answer is "yes, but it's proving to be very difficult."
It used to be that the primary cause of (commercial) jet noise was the engines. Manufacturers have managed to reduce the acoustic output from the engines (somewhat :) through engineering and operation changes (see here for example).
Other challenges include aerodynamic noise and structure-borne noise. Aerodynamic noise reduction can hopefully be achieved through shape changes. Structure-borne noise is a little difficult because it's difficult to mitigate without adding weight to the plane.
My personal feeling is that structure-borne noise reduction can be accomplished using active-vibration reduction, but then again, I'm more of a surface-transportation noise-guy than an aero/astro noise guy.
Geeks like us, and researchers looking to get more grant money, have been babbling about fusion, flying cars, a return to the moon, a trip to Mars, terraforming Mars, anti-gravity devices, transporters, replicators, eternal life, brain transplantation and human cloning for-fucking-ever. YOU KNOW WHAT? I AM FUCKING SICK OF READING ABOUT SPECULATIVE FLIMFLAM. I want to read, for once, a story like:
Flying cars being sold from reputable Web site for $20,000 RIGHT NOW
Holy shit: Man lands on Mars!
Fusion reactor perfected; lauded as "great success". Test reactor already tethered to power grid generating $BIGNUM megawatts; construction on fullscale reactor underway. AND...
Silent supersonic airliner makes first of new daily Transatlantic flights wearing $MAJOR_AIRLINE colours. Book tickets at $URL.
Stop wasting my fucking time until something is actually AVAILABLE NOW. God, I'm fucking sick of reading this kind of pie-in-the-sky bullshit! It's all over SlashDot and, to a lesser extent, all over the "mainstream" news media. Fuck this shit, I don't want to hear about how "at some point in the "near" future" we "may" have such-and-such. I want a fucking link to buy one on walmart.com.
Fucking Christ, are all research organisations just like us geeks-- starting projects but never finishing them?
Oh, and you over there at moller.com: STOP BABBLING ABOUT YOUR GOD-DAMNED FLYING CARS AND START SELLING THE FUCKING THINGS ALREADY!!! YOU'RE ALREADY 10 YEARS LATE, YOU FUCKWITS! And if the FAA won't let you sell them in the US, SELL THEM ELSEWHERE. RIGHT FUCKING NOW!
Honey, I shrunk the Cygwin
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.
That plane is used for training purposes to be the agressor, it looks like one of the Navy OpFor planes from Palomar. The us military uses mocked up soviet equipment, or sometimes even real soviet equipment to train against.
I used to have a cool sig, back when I cared
The bottom left photo is not a F-20. There were just 1 or 2 made, and they are owned by Northrop, not the Navy.
The F-5 in the lower left is owned by the Navy. The reason that it has the Red Star painted on it is that it's an agressor plane used by the Top Gun dogfighting school.
If tits were wings it'd be flying around.
The reason the Concorde was an economic failure was not the sonic boom - it was a failure because of the enormous fuel consumption per passenger, as well as the enormous maintenance costs per passenger. This was true even though the airlines purchased the Concordes for $1 apiece, and there was no purchase cost to amortize.
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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It's created constantly by supersonic flight. It's a byproduct of the air pressure in front of the plane being extremely high, steadily decreasing as you head back to the tail, and a sharp rise behind the tail when the pressure snaps back to normal.
This is why there are two booms from each aircraft. The first one from the pressure wave preceding the plane, and the second from the posterior wave.
"If we let things terrify us, life will not be worth living."
- Seneca
"the Economist thinks it likely that Boeing will be out of the civil aviation business entirely in ten years time" Well, certinally they will, because we all know that they aren't selling any planes right now, and it'd be impossible for them to develop any new planes out of composite materials with quieter engines. Oh yeah, there's no way things coule possibly turn around for them.
Riiiight...
Top right - F-15
Center - Modified F-5
Bottom left - Standard F-5, painted in TigerShark livery.
The F-20 is just slightly different frm the F-5, as evidenced by the extra bulk around the tail root.
This particular F-15B from NASA has a different nose. More pointed than a line model. That is why you were confused.
Would you like fries with that?
During the SR-71 development, Lockheed agreed to reimburse the cost of repairing windows broken due to the aircraft's sonic booms. To help people prepare for the sonic booms, they'd announce supersonic test flights ahead of time in the local paper. Once, they announced a flight but never actually made it. The complaints still streamed in though, from people wanting free windows replacements.
...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.
The sonic boom is constant. It is because the sound source is travelling than the sound itself, thus the wave doesn't have a chance to decay before it is regenerated by the travelling object. The individual waves add up to form the sonic boom.
When a jet flies by, you would hear two booms: one at the front when the nose pierces the air, and another at the rear when the air fills the void behind the aircraft (in theory its polarity would be opposite that of the first).
Read about it here: Doppler Shift
-Billco, Fnarg.com
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."
[Note: If someone can identify the third plane on the lower left corner of the picture, please tell me what it is.]
I could tell you, but then I'd have to kill you.
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.
No trespassing. Violators will be shot. Survivors will be shot again.
The main boom is the one I was describing, and as far as I can tell, it was accurate. At least the Wikipedia seems to agree with me:
"If we let things terrify us, life will not be worth living."
- Seneca
There are a number of additional reason why Concorde was not a commercial success and was withdrawn from service:-
1) The wings were virtually hand made. This was because at the time of manufacture CNC machines had not been really developed. As a consequence when the linings were put in the fuel tanks on the BA aircraft after the Paris crash, they found the shape of the fuel tanks on each aircraft were completely different. The TU144 (Concordski) had less complicated wings, due to the use of Canards on the front of the aircraft.
2) Concorde could only just make JFK from Paris. If the wind were in the wrong direction, the plane couldn't fly. The proposed (but never built) B version of Concorde could have flown Supersonic from Germany to JFK, and could have reached a number of other destinations from London.
3) The Avionics on Concorde needed to be replaced for the aircraft to continue in service past 2004. I know this as the company I work for built the engine controllers, which were the first controller to have full digital control (RB211 engines on the 747 didn't get this until the 1980's). Needless to say the work was cancelled.
4) After the Paris crash, the work carried out on the aircraft meant that the Air France Concorde could not operate fully loaded with 100 passengers. I believe as Air France could then no longer operate the aircraft economically, therefore withdrew their service. This also made the BA service unviable. Due to political reasons the aircraft were not sold to another air carrier that were prepared to continue operating the aircraft (Virgin Atlantic).
To date Concorde is one of only 2 aircraft with supercruise capability (flying above Mach 1 without afterburn); the other is the F22. It has flown more hours supersonically than all the other supersonic planes in the world.
I spoke to Sir Richard Branson (Owner of Virgin Atlantic) live on BBC TV the day before Concorde was withdrawn from service. I asked him when he expected the replacement for Concorde to enter service, and he replied "not for another 30 to 40 years". I would hope that the developments into reducing supersonic noise and jet engine fuel economy would allow the development of a large passenger jet within the next 15 to 20 years, but that depends on the airline market for such an aircraft. A small supersonic business jet capable of reaching mach 1.4 may be in service in as little as 3 to 4 years, especially as Concorde is no longer in service.
Concorde will end up in history as the aircraft equivalent of the SS Great Eastern; a large Brunel ship that was built some 50 years ahead of its time. It too was never a commercial success, and was scrapped 30 years after entering service. No ship of the size of Great Eastern was built under the SS Titanic era of the early 20th century.