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I remember as a kid hearing sonic booms and thinking it was so cool. I guess it was military planes in my area. I wonder how many people now even knows what i

I remember as a kid hearing sonic booms and thinking it was so cool. I guess it was military planes in my area. I wonder how many people now even knows what it sounds like. The article mentions commercial air flights taking half the time, but I wonder who needs that kind of speed when I see this- “According to ICCT, supersonic flights would burn up to 9x more fuel per passenger per kilometer than their subsonic flying buddies.“

hamburglar 3y ago
When I was a kid, my dad was a naval officer stationed on an aircraft carrier and I got to go on something called the “Dependent’s Day Cruise” where we sailed out offshore and got tours of the ship and they did a full-on airshow for us. Because we were out at sea, they could break the sound barrier with impunity, and it was mind-blowingly cool to have fighter jets flying over low enough that we could see the pilots, absolutely silently until that massive shockwave hit your chest. It’s surreal.
mpweiher 3y ago
> would burn up to 9x more fuel per passenger per kilometer That number seems a bit hyperbolic, even for Concorde, which was 1960s technology. Modern supersonics will be far lighter, use turbofans instead of turbojets, not require (or even have) afterburners etc. They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture. The truth will probably be somewhere in-between.
- heisenbit 3y ago
  > They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture. This fig leaf is transparent.
  - Maxion 3y ago
    If I burn 10^21 gallons of sustainable, carbon neutral, aviation fuel every year, what would happen? Somehow I think the CO2 sensor on Mauna Loa would need to be dug out from a piece of percipitated carbon.
    - regularfry 3y ago
      Mostly what would happen is a lot of questions about where you are hiding that Dyson sphere you need to power the carbon capture.
  - zmgsabst 3y ago
    How so? If the fuel is made from captured CO2, then there isn’t any net CO2 from burning it after.
    - ajuc 3y ago
      You could capture the CO2 and take a train. No matter how you get your clean fuel - burning more of it is worse for environment than burning less of it.
      - zmgsabst 3y ago
        Okay — but there’s no harm to the environment. You’re just not improving it. The grandparent claimed this was a “fig leaf”: instead, you made an ideological post about how we need to not do even environmentally neutral things — that doesn’t make carbon neutral air travel a “fig leaf”.
        ajuc 3y ago
        You can say anything is carbon neutral if you use synthetic fuel. It's meaningless at best, and manipulative at worst. Producing synthetic fuel requires energy.
        zmgsabst 3y ago
        Okay — like solar? …or nuclear? …or hydroelectric? …maybe geothermal? And yes, that’s correct: Synthetic fuels mean that it’s carbon neutral — that’s a fact, not a fig leaf.
        ajuc 3y ago
        Like oil, natural gas and coal which is top 3 of our energy sources worldwide. Together in 2021 they amounted to 130 000 out of 160 000 TWh of energy produced. Wasting energy is bad. Even if we actually used synthetic fuel. Even if we actually moved to 100% renewable energy sources - we'd still have limited amount of energy. And before we do - it's just PR. Source: https://i.imgur.com/vZkz3sf.png https://i.imgur.com/vZkz3sf.png https://ourworldindata.org/energy-mix https://ourworldindata.org/energy-mix
- carabiner 3y ago
  The 9x factor seems in the ballpark when you consider a Mach 2 jetliner will be going 2.5-3x faster than a subsonic one, and drag increases with the square of the airspeed.
  - implements 3y ago
    At constant altitude. I believe Concorde was actually more fuel efficient per passenger mile than a 747 when flying Mach 2 up near 60,000ft where the air was very thin, but as it took half the flight’s fuel simply to get that high and that fast the overall efficiency was much lower.
    - labcomputer 3y ago
      I am extremely skeptical of that claim. It might be true for the original 747-100 (with GE’s first turbofan engine) in unfavorable conditions, but it certainly isn’t for any 747 made in the last 40 years with even a semi-optimal flight plan. Wikipedia gives the TSFC of Concorde’s Rolls-Royce 593 engines as 1.195 lb/lbf-hr and 0.6 lb/lbf-hr for a 747-400’s Rolls-Royce RB211. So that’s 45% less fuel burn per pound of thrust in favor of the 747. Furthermore, drag increases as the cube of airspeed (which corresponds to fuel per mile scaling as speed squared). That means at constant air density, Concorde would consume (2.37)^2 = 5.6 times more fuel (not accounting for the difference in engines) A 747 cruising very low at 30k feet would have ~4 the air density to contend with, but even that doesn’t make up for the speed difference. 747-400’s routinely cruise at over 40k feet… Unfortunately, you can’t just wave your hands and shout “supersonic turbofan”, because high bypass ratios (what accounts for subsonic efficiency gains since the 1960’s) are incompatible with supersonic flight. Edit, one more thing: The General Electric GEnx found on modern 747-8’s are 15% more efficient than the old 747-400’s engines! What is true is that a Concorde flying at subsonic speeds is more efficient per passenger mile than a 747. But that’s mostly due to the very high fineness ratio and drag-reduction-above-all-else design philosophy.
- hef19898 3y ago
  The Concorde is still pretty top notch, tech wise. As far as supersonic and supercruise jet engines go, they are all military. Civilian engine development went all in improving noise levels and fuel economy. And without a viable market, no engine OEM will invest the billions needed to develop a civil supersonic engine. So it is either a huge market, or various governments foot the RnD bills. Both of which are far, far away. All technological promises regarding civilian supersonics only exist in fancy renderings and pitch decks, there is no substance behind. Even less than there is with the various eVTOLs, at least those actually fly. Well, some of them that is...
operatingthetan 3y ago
My girlfriend and I were hanging out at a lake east of Issaquah near seattle and suddenly two Growlers came down low over the lake and we were subject to two sonic booms which was amazing. They sounded sort of like a resonant crack of thunder but much louder. They flew over a boat in the middle of the lake and I shit you not someone on it screamed "AMERICA F YEAH." It turned out this lake was one of the ones they filmed for the new Top Gun film, but it was common for Whidbey pilots to buzz it on their way back to the NAS.
rwmj 3y ago
I read some contemporary articles in a Private Eye annual from the 1960s and the problem was not really the noise but the structural damage that was (allegedly) being caused. I don't know how real that was, but in the UK concerns over structural damage to buildings was what lead to the ban. As for this plane, what are the elements of the design that reduce sonic booms? The comically long nose?
- Mistletoe 3y ago
  I think it is mainly the comically long nose. https://www.thedrive.com/the-war-zone/44307/behold-the-x-59-quiet-supersonic-test-jets-absolutely-epic-schnoz https://www.thedrive.com/the-war-zone/44307/behold-the-x-59-...
hansthehorse 3y ago
My daughter lives relatively close to Cape Canaveral and hears sonic booms from the returning Spacex first stage quite frequently, as does the surrounding neighborhood.

hamburglar 3y ago

When I was a kid, my dad was a naval officer stationed on an aircraft carrier and I got to go on something called the “Dependent’s Day Cruise” where we sailed out offshore and got tours of the ship and they did a full-on airshow for us. Because we were out at sea, they could break the sound barrier with impunity, and it was mind-blowingly cool to have fighter jets flying over low enough that we could see the pilots, absolutely silently until that massive shockwave hit your chest. It’s surreal.

mpweiher 3y ago

> would burn up to 9x more fuel per passenger per kilometer That number seems a bit hyperbolic, even for Concorde, which was 1960s technology. Modern supersonics will be far lighter, use turbofans instead of turbojets, not require (or even have) afterburners etc. They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture. The truth will probably be somewhere in-between.

heisenbit 3y ago
> They also claim that they will be net-zero Carbon due to advances in sustainable aviation fuels, with processes like CO2-fuel direct air capture. This fig leaf is transparent.
- Maxion 3y ago
  If I burn 10^21 gallons of sustainable, carbon neutral, aviation fuel every year, what would happen? Somehow I think the CO2 sensor on Mauna Loa would need to be dug out from a piece of percipitated carbon.
  - regularfry 3y ago
    Mostly what would happen is a lot of questions about where you are hiding that Dyson sphere you need to power the carbon capture.
- zmgsabst 3y ago
  How so? If the fuel is made from captured CO2, then there isn’t any net CO2 from burning it after.
  - ajuc 3y ago
    You could capture the CO2 and take a train. No matter how you get your clean fuel - burning more of it is worse for environment than burning less of it.
    - zmgsabst 3y ago
      Okay — but there’s no harm to the environment. You’re just not improving it. The grandparent claimed this was a “fig leaf”: instead, you made an ideological post about how we need to not do even environmentally neutral things — that doesn’t make carbon neutral air travel a “fig leaf”.
      - ajuc 3y ago
        You can say anything is carbon neutral if you use synthetic fuel. It's meaningless at best, and manipulative at worst. Producing synthetic fuel requires energy.
        zmgsabst 3y ago
        Okay — like solar? …or nuclear? …or hydroelectric? …maybe geothermal? And yes, that’s correct: Synthetic fuels mean that it’s carbon neutral — that’s a fact, not a fig leaf.
        ajuc 3y ago
        Like oil, natural gas and coal which is top 3 of our energy sources worldwide. Together in 2021 they amounted to 130 000 out of 160 000 TWh of energy produced. Wasting energy is bad. Even if we actually used synthetic fuel. Even if we actually moved to 100% renewable energy sources - we'd still have limited amount of energy. And before we do - it's just PR. Source: https://i.imgur.com/vZkz3sf.png https://i.imgur.com/vZkz3sf.png https://ourworldindata.org/energy-mix https://ourworldindata.org/energy-mix
carabiner 3y ago
The 9x factor seems in the ballpark when you consider a Mach 2 jetliner will be going 2.5-3x faster than a subsonic one, and drag increases with the square of the airspeed.
- implements 3y ago
  At constant altitude. I believe Concorde was actually more fuel efficient per passenger mile than a 747 when flying Mach 2 up near 60,000ft where the air was very thin, but as it took half the flight’s fuel simply to get that high and that fast the overall efficiency was much lower.
  - labcomputer 3y ago
    I am extremely skeptical of that claim. It might be true for the original 747-100 (with GE’s first turbofan engine) in unfavorable conditions, but it certainly isn’t for any 747 made in the last 40 years with even a semi-optimal flight plan. Wikipedia gives the TSFC of Concorde’s Rolls-Royce 593 engines as 1.195 lb/lbf-hr and 0.6 lb/lbf-hr for a 747-400’s Rolls-Royce RB211. So that’s 45% less fuel burn per pound of thrust in favor of the 747. Furthermore, drag increases as the cube of airspeed (which corresponds to fuel per mile scaling as speed squared). That means at constant air density, Concorde would consume (2.37)^2 = 5.6 times more fuel (not accounting for the difference in engines) A 747 cruising very low at 30k feet would have ~4 the air density to contend with, but even that doesn’t make up for the speed difference. 747-400’s routinely cruise at over 40k feet… Unfortunately, you can’t just wave your hands and shout “supersonic turbofan”, because high bypass ratios (what accounts for subsonic efficiency gains since the 1960’s) are incompatible with supersonic flight. Edit, one more thing: The General Electric GEnx found on modern 747-8’s are 15% more efficient than the old 747-400’s engines! What is true is that a Concorde flying at subsonic speeds is more efficient per passenger mile than a 747. But that’s mostly due to the very high fineness ratio and drag-reduction-above-all-else design philosophy.
hef19898 3y ago
The Concorde is still pretty top notch, tech wise. As far as supersonic and supercruise jet engines go, they are all military. Civilian engine development went all in improving noise levels and fuel economy. And without a viable market, no engine OEM will invest the billions needed to develop a civil supersonic engine. So it is either a huge market, or various governments foot the RnD bills. Both of which are far, far away. All technological promises regarding civilian supersonics only exist in fancy renderings and pitch decks, there is no substance behind. Even less than there is with the various eVTOLs, at least those actually fly. Well, some of them that is...

operatingthetan 3y ago

My girlfriend and I were hanging out at a lake east of Issaquah near seattle and suddenly two Growlers came down low over the lake and we were subject to two sonic booms which was amazing. They sounded sort of like a resonant crack of thunder but much louder. They flew over a boat in the middle of the lake and I shit you not someone on it screamed "AMERICA F YEAH." It turned out this lake was one of the ones they filmed for the new Top Gun film, but it was common for Whidbey pilots to buzz it on their way back to the NAS.

rwmj 3y ago

I read some contemporary articles in a Private Eye annual from the 1960s and the problem was not really the noise but the structural damage that was (allegedly) being caused. I don't know how real that was, but in the UK concerns over structural damage to buildings was what lead to the ban. As for this plane, what are the elements of the design that reduce sonic booms? The comically long nose?

Mistletoe 3y ago
I think it is mainly the comically long nose. https://www.thedrive.com/the-war-zone/44307/behold-the-x-59-quiet-supersonic-test-jets-absolutely-epic-schnoz https://www.thedrive.com/the-war-zone/44307/behold-the-x-59-...

hansthehorse 3y ago

My daughter lives relatively close to Cape Canaveral and hears sonic booms from the returning Spacex first stage quite frequently, as does the surrounding neighborhood.