4 ms·

NASA Claims Supersonic Breakthrough For Biz Jets

80 points by yairharel 15y ago

lysol 15y ago
Don't editorialize the headline. The article is much more nuanced than the headline suggests and it belittles an amazing achievement.
- marklabedz 15y ago
  Agree with your analysis, but OP used the original title from Aviation Week.
  - _delirium 15y ago
    It's been edited; the original submission was "The end of the sonic boom is in sight". Though actually that doesn't seem that inaccurate; the "supersonic breakthrough" discussed in the article is precisely the effective reduction of sonic booms. (Incidentally, Twitter is a good source for finding what titles were before they were edited. In this case I found it at https://twitter.com/#!/newsyc20/status/187650762111844353 https://twitter.com/#!/newsyc20/status/187650762111844353)
fasteddie31003 15y ago
I assume the reduction in sonic boom is a result of the shape of the aircraft. Does anyone have any ideas on what these new shapes could look like? Links?
- Symmetry 15y ago
  Could this press release be related to this other one? http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.html http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.h...
- b_emery 15y ago
  Maybe these? http://www.wired.com/autopia/2010/07/aerospace-giants-design-supersonic-jets-with-a-silent-boom/ http://www.wired.com/autopia/2010/07/aerospace-giants-design... This has a small image of a test vehicle: http://www.nasa.gov/missions/research/sonic_booms.html http://www.nasa.gov/missions/research/sonic_booms.html
  - fasteddie31003 15y ago
    I really want planes to look like the ones in the Wired article.
CountHackulus 15y ago
At 70PNLdB, I doubt anyone in their car could hear it. In fact pretty much only rural quiet areas will hear it. Though I'm sure there's going to be some "concerned citizens" that claim that the sonic booms are causing their children migraines, or something similar. Still, living at one end of Canada and having friends at the other end, I'm excited for the possibility quiet overland supersonic flight.
- Anechoic 15y ago
  At 70PNLdB, I doubt anyone in their car could hear it. In fact pretty much only rural quiet areas will hear it. 70 PNL dB is fairly loud, it will be very noticeable in urban areas and extremely disruptive in rural areas. 65 dB Ldn is the target for normal aircraft and most experts agree that limit is way too high. The research represents a significant decrease in noise from supersonic aircraft, but we're a long way from "quiet."
  - CountHackulus 15y ago
    Got any sources for that? I'm interested in reading that research. Couple anecdotes: I work in a semi rural neighborhood that's 2km from a regional airport (a bit off to the side of the approach path). I work right next to a window and haven't once heard an airplane go by. Now, this might be due to our shielded glass and white noise generators in the ceiling, but that's not bad. Second anecdote, there was an airport downtown on the water that was re-opening with an airline running Bombardier Q400s (Porter Airlines at Billy Bishop). There was a group of protesters that were claiming that the noise would ruin the quiet of a nearby spit. So on the launch day, before the sun rose, they gathered at the spit to protest. Unfortunately for them, they missed the first flight as their talking had drowned it out. Maybe it's just because I lived next to the railroad tracks for 20 years, but I say, bring on the jets.
    - ismarc 15y ago
      More anecdotes, but, I lived 1 1/2 miles perpendicular to the most frequent runway of an airport. If you were outside, you could hear every plane take off and it disturbed an otherwise perfect place to live. However, with zero noise considerations in building, couldn't hear a thing inside. On the other hand, I now live within 2 miles of a medium sized metro area and the normal sound of traffic is louder than the planes were. So while I never took db readings, environment is going to play a huge impact, but even minimal insulation will make it inaudible.
grannyg00se 15y ago
"Boom is proportional to weight, and a small supersonic business is likely to meet that level" Really? I would expect it to be relaated to size and shape.
- icegreentea 15y ago
  Well, it's proportional to volume of displaced air, which should scale more or less linearly with the empty weight of an airplane.
swalsh 15y ago
The jets are aimed to become available around 2025. On a some what unrelated note, does anyone here know what the evolution of commercial planes is in terms of fuel sources? Sources i've seen put non-traditional peak oil at 2030, so it would seem that by the time this technology is developed the fuel could be prohibitively expensive. Will alternative energies provide enough power for super sonic flight?
- Hoff 15y ago
  "Biomass fuel" for commercial jet aircraft is seeing some interest: http://atwonline.com/eco-aviation/news/ten-airlines-agree-purchase-biomass-derived-jet-fuel-0621 http://atwonline.com/eco-aviation/news/ten-airlines-agree-pu... http://motherjones.com/environment/2008/01/virgin-airlines-powered-pond-scum http://motherjones.com/environment/2008/01/virgin-airlines-p...
- ars 15y ago
  There isn't any difference between plane fuel sources vs cars or power plants. In other words there is no change you can make to the plane. The only change is to the fuel source and that applies to everything, not just planes. And don't try to predict peak oil - every single prediction ever made of it has been wrong. And not just a little bit wrong, wildly incorrect. Every time we seem to run out of oil or natural gas we find more - known oil reserves have never been higher.
  - mikeash 15y ago
    There's a huge difference between planes and these others. Power plants can run on a huge variety of other sources, like wind, solar, hydro, or nuclear. Cars can fairly reasonably run on electricity. Airliners as we know them must use some kind of high-density liquid fuel.
    - cwmccarthy 15y ago
      It sounds like ars was trying to suggest that the fuel we currently use is very similar to that aircraft use (ie. if you can synthesize oil you kill two birds with one stone) The cetane number and the flash point is a little different, but to simplify, diesel is Jet-A with additives, mainly for lubrication. You can put jet fuel in a diesel truck and it'll work fine, the military often mixes it in to avoid two separate fuel supplies. The same thing can be done with piston aircraft (100LL vs auto gas) Also, I can only imagine the use of a biomass mix will increase. Last year the USAF was saying it was roughly 10x the cost, but that's dropping with production scale while oil obviously is only going up.
Florin_Andrei 15y ago
> it is possible to design configurations that combine low sonic boom with low cruise drag, characteristics once thought to be mutually exclusive Why mutually exclusive? (just curious) What was the justification previously offered?
- ajross 15y ago
  One possibility is that static analysis for supersonic waveforms is a whole lot easier if you have planar shock fronts (i.e. the shock waves coming off the airframe make simple polygonal shapes). Back when this was done with pencil and paper it was really the only option short of building and testing real objects, so if you wanted to do any sort of optimization you had to do it with airframes that produced big planar shocks. But those big, single shock waves are, of course, perceived by the listener as a "boom".
ChuckMcM 15y ago
Perhaps we'll officially acknowledge the existence of the Aurora :-). There has been great progress in the open literature about developing super-sonic craft which mitigate and possibly eliminate the 'boom' effects. The MIT paper [1] was worth a read as well. [1] http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.html http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.h...
v3rt 15y ago
If a big proportion of business-travel-miles are flown over oceans (which seems reasonable between the most common routes like New York-London, SF-Tokyo, SF-HK...), would it not be cost and time efficient to use low-drag but noisy planes and just hit the speed of sound over the ocean? Flying .9 Mach over the land and 1.5 (or whatever was reasonable) would still save a lot of time and wouldn't disturb anyone.
- stretchwithme 15y ago
  And that's what they were doing before the demise of the Concorde.

80 points by yairharel 15y ago

lysol 15y ago

Don't editorialize the headline. The article is much more nuanced than the headline suggests and it belittles an amazing achievement.

marklabedz 15y ago
Agree with your analysis, but OP used the original title from Aviation Week.
- _delirium 15y ago
  It's been edited; the original submission was "The end of the sonic boom is in sight". Though actually that doesn't seem that inaccurate; the "supersonic breakthrough" discussed in the article is precisely the effective reduction of sonic booms. (Incidentally, Twitter is a good source for finding what titles were before they were edited. In this case I found it at https://twitter.com/#!/newsyc20/status/187650762111844353 https://twitter.com/#!/newsyc20/status/187650762111844353)

fasteddie31003 15y ago

I assume the reduction in sonic boom is a result of the shape of the aircraft. Does anyone have any ideas on what these new shapes could look like? Links?

Symmetry 15y ago
Could this press release be related to this other one? http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.html http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.h...
b_emery 15y ago
Maybe these? http://www.wired.com/autopia/2010/07/aerospace-giants-design-supersonic-jets-with-a-silent-boom/ http://www.wired.com/autopia/2010/07/aerospace-giants-design... This has a small image of a test vehicle: http://www.nasa.gov/missions/research/sonic_booms.html http://www.nasa.gov/missions/research/sonic_booms.html
- fasteddie31003 15y ago
  I really want planes to look like the ones in the Wired article.

CountHackulus 15y ago

At 70PNLdB, I doubt anyone in their car could hear it. In fact pretty much only rural quiet areas will hear it. Though I'm sure there's going to be some "concerned citizens" that claim that the sonic booms are causing their children migraines, or something similar. Still, living at one end of Canada and having friends at the other end, I'm excited for the possibility quiet overland supersonic flight.

Anechoic 15y ago
At 70PNLdB, I doubt anyone in their car could hear it. In fact pretty much only rural quiet areas will hear it. 70 PNL dB is fairly loud, it will be very noticeable in urban areas and extremely disruptive in rural areas. 65 dB Ldn is the target for normal aircraft and most experts agree that limit is way too high. The research represents a significant decrease in noise from supersonic aircraft, but we're a long way from "quiet."
- CountHackulus 15y ago
  Got any sources for that? I'm interested in reading that research. Couple anecdotes: I work in a semi rural neighborhood that's 2km from a regional airport (a bit off to the side of the approach path). I work right next to a window and haven't once heard an airplane go by. Now, this might be due to our shielded glass and white noise generators in the ceiling, but that's not bad. Second anecdote, there was an airport downtown on the water that was re-opening with an airline running Bombardier Q400s (Porter Airlines at Billy Bishop). There was a group of protesters that were claiming that the noise would ruin the quiet of a nearby spit. So on the launch day, before the sun rose, they gathered at the spit to protest. Unfortunately for them, they missed the first flight as their talking had drowned it out. Maybe it's just because I lived next to the railroad tracks for 20 years, but I say, bring on the jets.
  - ismarc 15y ago
    More anecdotes, but, I lived 1 1/2 miles perpendicular to the most frequent runway of an airport. If you were outside, you could hear every plane take off and it disturbed an otherwise perfect place to live. However, with zero noise considerations in building, couldn't hear a thing inside. On the other hand, I now live within 2 miles of a medium sized metro area and the normal sound of traffic is louder than the planes were. So while I never took db readings, environment is going to play a huge impact, but even minimal insulation will make it inaudible.

grannyg00se 15y ago

"Boom is proportional to weight, and a small supersonic business is likely to meet that level" Really? I would expect it to be relaated to size and shape.

icegreentea 15y ago
Well, it's proportional to volume of displaced air, which should scale more or less linearly with the empty weight of an airplane.

swalsh 15y ago

The jets are aimed to become available around 2025. On a some what unrelated note, does anyone here know what the evolution of commercial planes is in terms of fuel sources? Sources i've seen put non-traditional peak oil at 2030, so it would seem that by the time this technology is developed the fuel could be prohibitively expensive. Will alternative energies provide enough power for super sonic flight?

Hoff 15y ago
"Biomass fuel" for commercial jet aircraft is seeing some interest: http://atwonline.com/eco-aviation/news/ten-airlines-agree-purchase-biomass-derived-jet-fuel-0621 http://atwonline.com/eco-aviation/news/ten-airlines-agree-pu... http://motherjones.com/environment/2008/01/virgin-airlines-powered-pond-scum http://motherjones.com/environment/2008/01/virgin-airlines-p...
ars 15y ago
There isn't any difference between plane fuel sources vs cars or power plants. In other words there is no change you can make to the plane. The only change is to the fuel source and that applies to everything, not just planes. And don't try to predict peak oil - every single prediction ever made of it has been wrong. And not just a little bit wrong, wildly incorrect. Every time we seem to run out of oil or natural gas we find more - known oil reserves have never been higher.
- mikeash 15y ago
  There's a huge difference between planes and these others. Power plants can run on a huge variety of other sources, like wind, solar, hydro, or nuclear. Cars can fairly reasonably run on electricity. Airliners as we know them must use some kind of high-density liquid fuel.
  - cwmccarthy 15y ago
    It sounds like ars was trying to suggest that the fuel we currently use is very similar to that aircraft use (ie. if you can synthesize oil you kill two birds with one stone) The cetane number and the flash point is a little different, but to simplify, diesel is Jet-A with additives, mainly for lubrication. You can put jet fuel in a diesel truck and it'll work fine, the military often mixes it in to avoid two separate fuel supplies. The same thing can be done with piston aircraft (100LL vs auto gas) Also, I can only imagine the use of a biomass mix will increase. Last year the USAF was saying it was roughly 10x the cost, but that's dropping with production scale while oil obviously is only going up.

Florin_Andrei 15y ago

> it is possible to design configurations that combine low sonic boom with low cruise drag, characteristics once thought to be mutually exclusive Why mutually exclusive? (just curious) What was the justification previously offered?

ajross 15y ago
One possibility is that static analysis for supersonic waveforms is a whole lot easier if you have planar shock fronts (i.e. the shock waves coming off the airframe make simple polygonal shapes). Back when this was done with pencil and paper it was really the only option short of building and testing real objects, so if you wanted to do any sort of optimization you had to do it with airframes that produced big planar shocks. But those big, single shock waves are, of course, perceived by the listener as a "boom".

ChuckMcM 15y ago

Perhaps we'll officially acknowledge the existence of the Aurora :-). There has been great progress in the open literature about developing super-sonic craft which mitigate and possibly eliminate the 'boom' effects. The MIT paper [1] was worth a read as well. [1] http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.html http://web.mit.edu/newsoffice/2012/supersonic-biplane-0319.h...

v3rt 15y ago

If a big proportion of business-travel-miles are flown over oceans (which seems reasonable between the most common routes like New York-London, SF-Tokyo, SF-HK...), would it not be cost and time efficient to use low-drag but noisy planes and just hit the speed of sound over the ocean? Flying .9 Mach over the land and 1.5 (or whatever was reasonable) would still save a lot of time and wouldn't disturb anyone.

stretchwithme 15y ago
And that's what they were doing before the demise of the Concorde.