5 ms·

Apparently (can't find the article I read on it) the noise would be much less of a problem today. The magnitude of the sonic boom is relative to mass, and mode

by mabbo 10y ago

Apparently (can't find the article I read on it) the noise would be much less of a problem today. The magnitude of the sonic boom is relative to mass, and modern planes are being built lighter and lighter (to save on fuel). Something like a 50-seat mostly-carbon-fiber super sonic aircraft at 50,000 ft might well be perfectly fine to fly over land at Mach 2. The smaller size might also help with the problem of empty seats. As well, ideas like wings that change shape/angle for different portions of the flight could also help. Someone just needs to put down the R&D money and take the risk to build such a plane.

Fuddh 10y ago
I did not know this - great point! Actually being able to use simulations to a much larger extent than was possible back when Concorde was being developed must play a role in lowering the costs of building a new supersonic aircraft. I believe this is what Boom is trying to do! Let's hope they can spur more investments into this field - it would be very cool if we got to see supersonic travel again :)
- mabbo 10y ago
  Apparently, I was wrong! While many organizations are working on reducing sonic booms, mass is not a factor.
brian_cloutier 10y ago
That doesn't sound reasonable. The sonic boom is caused by (I had thought) air being compressed at the front of the plane. That would mean the loudness is determined by speed and shape of the plane. The only way mass would have an effect is if the exhaust (which heavier planes presumably generate more of) contributed to the sonic boom, which doesn't sound right. I'll believe that modern planes might generate smaller sonic booms, being more efficient sounds like it's related to how you displace the air, which sounds very related to the size of the boom, but I don't believe you that mass is related.
- mcguire 10y ago
  Not necessarily. The amount of air displaced is related to the mass of the aircraft. A heavier plane displaces more air, leading to a more energetic boom.
  - nf05papsjfVbc 10y ago
    Are you suggesting that if we have two planes of the same size and shape, the heavier one displaces more air? I can understand that objects floating on water follow that principle but that's because they are floating. Once fully suspended in water, I think the amount of water they displace is just their volume. Shouldn't it be likewise for aircrafts in the atmosphere?
    - mcguire 10y ago
      To maintain level flight, a plane has to generate lift equal to its weight. It generates lift by forcing a mass of air down. More mass means more air disturbed.
      - nf05papsjfVbc 10y ago
        Interesting. I never thought of it this way. Thanks for helping me see the missing part of the picture.
        mcguire 10y ago
        When people explain flight through Bournoulli or whatever, they tend to forget Newton's basic laws, which really are the simplest way to understand flight. It won't make you an aerospace engineer, though.
      - mzs 10y ago
        You are describing ground effect not lift.
        10y ago
ohitsdom 10y ago
NASA is working on quieter sonic booms. http://arstechnica.com/science/2016/02/meet-nasas-new-x-planes-quiet-sonic-booms-and-engines-at-the-back/ http://arstechnica.com/science/2016/02/meet-nasas-new-x-plan...
- digi_owl 10y ago
  I seem to recall that they did some testing with a fat nosed F-5 that showed such a configuration greatly reducing the shockwave.
  - spitfire 10y ago
    https://en.wikipedia.org/wiki/Shaped_Sonic_Boom_Demonstration https://en.wikipedia.org/wiki/Shaped_Sonic_Boom_Demonstratio... Pretty cool looking actually. Though it does dull the "fighter-planes-fighter-plane" look of the F-5 a bit.
    - iainmerrick 10y ago
      I disagree, it looks much better! It's like something right out of Flash Gordon or Dan Dare.
LeifCarrotson 10y ago
The magnitude of the sonic boom is not relative to mass. It is relative to the altitude and to the speed of the aircraft, and the duration and maximum amplitude of the shock wave are dependent on the shape of the aircraft. You may have misread an article describing pounds-per-square-foot as a measure of sonic boom intensity. This measurement is not about the mass or density of the aircraft relative to its area, this is the change in air pressure at the ground caused by the sound wave.

by mabbo 10y ago

Fuddh 10y ago

I did not know this - great point! Actually being able to use simulations to a much larger extent than was possible back when Concorde was being developed must play a role in lowering the costs of building a new supersonic aircraft. I believe this is what Boom is trying to do! Let's hope they can spur more investments into this field - it would be very cool if we got to see supersonic travel again :)

mabbo 10y ago
Apparently, I was wrong! While many organizations are working on reducing sonic booms, mass is not a factor.

brian_cloutier 10y ago

That doesn't sound reasonable. The sonic boom is caused by (I had thought) air being compressed at the front of the plane. That would mean the loudness is determined by speed and shape of the plane. The only way mass would have an effect is if the exhaust (which heavier planes presumably generate more of) contributed to the sonic boom, which doesn't sound right. I'll believe that modern planes might generate smaller sonic booms, being more efficient sounds like it's related to how you displace the air, which sounds very related to the size of the boom, but I don't believe you that mass is related.

mcguire 10y ago
Not necessarily. The amount of air displaced is related to the mass of the aircraft. A heavier plane displaces more air, leading to a more energetic boom.
- nf05papsjfVbc 10y ago
  Are you suggesting that if we have two planes of the same size and shape, the heavier one displaces more air? I can understand that objects floating on water follow that principle but that's because they are floating. Once fully suspended in water, I think the amount of water they displace is just their volume. Shouldn't it be likewise for aircrafts in the atmosphere?
  - mcguire 10y ago
    To maintain level flight, a plane has to generate lift equal to its weight. It generates lift by forcing a mass of air down. More mass means more air disturbed.
    - nf05papsjfVbc 10y ago
      Interesting. I never thought of it this way. Thanks for helping me see the missing part of the picture.
      - mcguire 10y ago
        When people explain flight through Bournoulli or whatever, they tend to forget Newton's basic laws, which really are the simplest way to understand flight. It won't make you an aerospace engineer, though.
    - mzs 10y ago
      You are describing ground effect not lift.
      - 10y ago

ohitsdom 10y ago

NASA is working on quieter sonic booms. http://arstechnica.com/science/2016/02/meet-nasas-new-x-planes-quiet-sonic-booms-and-engines-at-the-back/ http://arstechnica.com/science/2016/02/meet-nasas-new-x-plan...

digi_owl 10y ago
I seem to recall that they did some testing with a fat nosed F-5 that showed such a configuration greatly reducing the shockwave.
- spitfire 10y ago
  https://en.wikipedia.org/wiki/Shaped_Sonic_Boom_Demonstration https://en.wikipedia.org/wiki/Shaped_Sonic_Boom_Demonstratio... Pretty cool looking actually. Though it does dull the "fighter-planes-fighter-plane" look of the F-5 a bit.
  - iainmerrick 10y ago
    I disagree, it looks much better! It's like something right out of Flash Gordon or Dan Dare.

LeifCarrotson 10y ago

The magnitude of the sonic boom is not relative to mass. It is relative to the altitude and to the speed of the aircraft, and the duration and maximum amplitude of the shock wave are dependent on the shape of the aircraft. You may have misread an article describing pounds-per-square-foot as a measure of sonic boom intensity. This measurement is not about the mass or density of the aircraft relative to its area, this is the change in air pressure at the ground caused by the sound wave.