Want to read Slashdot from your mobile device? Point it at m.slashdot.org and keep reading!

 



Forgot your password?
typodupeerror
Check out the new SourceForge HTML5 internet speed test! No Flash necessary and runs on all devices. ×
NASA Transportation Technology

Rockwell Collins To Develop Cockpit Display To Show Sonic Boom Over Land 73

An anonymous reader writes: Under contract from NASA, Rockwell Collins is developing equipment to let pilots of supersonic craft know where a sonic boom will be produced. The hope is to make supersonic flight over land practical. Flying higher widens impacts but lessens intensity. “In order for supersonic travel over land to happen, pilots will need an intuitive display interface that tells them where the aircraft’s sonic boom is occurring,” said John Borghese, vice president, Advanced Technology Center for Rockwell Collins. “Our team of experts will investigate how best to show this to pilots in the cockpit and develop guidance to most effectively modify the aircraft’s flight path to avoid populated areas or prevent sonic booms.”
This discussion has been archived. No new comments can be posted.

Rockwell Collins To Develop Cockpit Display To Show Sonic Boom Over Land

Comments Filter:
  • by QuietLagoon ( 813062 ) on Sunday May 17, 2015 @09:35AM (#49710413)
    ... now the pilots can aim the sonic boom to hit the area where their mother-in-law lives....
    • by duckintheface ( 710137 ) on Sunday May 17, 2015 @09:45AM (#49710463)

      becasue you love peace and quiet, well screw you. Is it ok to hit folks in low population areas with a shocking, loud noise. Helpful hint: NO, it is not.

      • by Anonymous Coward

        becasue you love peace and quiet, well screw you. Is it ok to hit folks in low population areas with a shocking, loud noise. Helpful hint: NO, it is not.

        Sonic booms and noise pollution - well all pollution - should be where it rightfully belongs; in poor people's backyards.

    • Re: (Score:2, Informative)

      by Anonymous Coward

      You know that the sonic boom is a constant thing, trailing behind a plane flying super-sonic, right? This will just help pilots by telling them when it's alright to go super sonic.

      • Indeed. This constant "boom" was given an unfortunately misleading name. It is more like an infinite Tsunami, able to sweep over and inundate everything.
  • I think they're developing it so the Israelis will be able better able to piss off the Palestinians.
  • by Anonymous Coward

    Seems like something which could be done by a 'back room' computer when the flight path is being generated. At that point, you could modify the flight path to put the sonic boom where you want.

  • by 140Mandak262Jamuna ( 970587 ) on Sunday May 17, 2015 @10:21AM (#49710637) Journal
    To make supersonic flight possible over sea or over land, the cost must come down. Without reducing the cost it makes no sense to worry about sonic boom, or figuring out ways to show the pilot where it hits the ground and its intensity.

    Also the sonic boom issue was more FUD by Boeing, Douglas and Lockheed than the real issue. Back in the 80s, before the oil crisis, these companies wanted to stop British Aerospace and Aerospatiale from establishing a bridgehead at the luxury travel sector using Corcorde and its derivatives. But thankfully the Arab oil shock stopped Concorde.

    Think about it, the total energy of all the shock and sonic boom is equal to amount of jet fuel burnt. During cruise at Mach 2.05 each Olympus 593 was producing around 10,000 lb of thrust, equivalent to 36,000 horsepower per engine.[18] [wikipedia.org] Two engines, 72000 HP. Or 54 kilowatt, or 54,0000 joules/sec. If all of it ends up as sonic boom, (neglecting skin friction) you are going to spread 54,0000 joules every second over several square miles. Compare this to peak solar radiation 1000 joules per square meter. OK that is purely thermal but this is mechanical. So let us take 10 mph wind. 16kmph. 4.44 m/s. Over 1 sq m cross section, mass flow rate is 4.44 * density of air/second. Air is 1 Kg/m^3. So it is 4.44 kg. 4.44 m/s velocity. Works out to kinetic power (power, not energy because we are using mass flow rate, not mass) of 0.5*mdot*v^2 = 22 joules/sec. This is per square meter. or 22 watts per square meter. 22 million watts per square kilometer. Let us round it up to a nice 100 million watts for several square kilometers. Compare that to 54 kilowatt, total maximum possible power output of those two turbojet engines. 100,000 kW for 10 mph wind vs 54 kW for Concorde. Our eardrums and instruments are sensitive enough to pick up the sonic boom over 10mph wind, but thats about it. Barely detectable. Sonic booms deafening people, cracking buildings and killing birds are all FUD.

    But cost... That is no mean thing to solve. In supersonic flight the energy needed to overcome the drag created by the shock wave is so high, there is no easy way to reduce the energy consumption. Only way to bring down the cost is to bring down the cost of fuel. The only way to make fuel cheaper is for the world to switch to non-fossil fules in such a large scale the oil industry collapses and oil falls to something like 5 dollar a barrel ( 2015 dollar not 1978 dollar).

    • by Greyfox ( 87712 )
      Back in the 80's at Robins Air Force Base, the fighter jets would drop a sonic boom on the area every week or so. They weren't any worse than a distant thunderstorm and significantly less bad than a nearby thunderstorm. I'm frequently surprised at all the hysteria over them, especially considering how often they occur over most of the continental USA (Never.) In the top 1000 things to worry about or be annoyed by, that shouldn't even be on the list.
      • Some of the hysteria is probably because a very low-altitude plane flying supersonic can probably break windows, so people are worried about that. Of course, we're talking about higher-altitude planes here, so that isn't really justified.

        The other worry is probably the frequency of the booms. One boom a month isn't a big deal, but what if they decide to make a frequent flight path over your house in the suburbs or in the country? Now you've got sonic booms every day, throughout the day. No one wants tha

        • by Greyfox ( 87712 )
          Mythbusters tested that. The guy had to be flying something crazy like 1000 feet in order to cause any damage like that. Very few people sane enough to be allowed to fly a supersonic aircraft would ever actually fly one that low at those speeds. Plow into a bird and you wouldn't even know how you died.
      • We also get a sonic boom every few weeks (Beersheba Israel, and we got them when I lived in Haifa as well). It's less noise than a car going by, and lasts for less time. I'm sure if you buzz a shack at Mach 2 the boom would be deafening, but typical combat aircraft at typical don't-SAM-me altitudes don't make much noise. I've also had the pleasure of hearing the double sonic boom from the STS orbiters coming in to land over Florida. I don't know how fast they were going, but even those booms, though a bit
      • They can be very loud. I was on an airshow when an English electric lightning flew supersonic at low level over the crowd (a practice now banned). That hurt!
    • by rossdee ( 243626 )

      "To make supersonic flight possible over sea or over land, the cost must come down"

      I think you are missing the word 'commercial' in that statement.

      For military flight, cost isn't such a big issue.

      • by PPH ( 736903 )

        For military flight, cost isn't such a big issue.

        But the detectability of supersonic aircraft is. So this is probably the customer at whom this technology is targeted.

    • Think about it, the total energy of all the shock and sonic boom is equal to amount of jet fuel burnt

      Well duh, ANY engine noise is "energy wasted on shaking the air" as any engineer can tell you. A 787 is nice and quiet compared to other airliners but it's still burning fuel to shake some air. It is a legit question to ask if it is *economical* to shake the air at the sonic boom level.

      • by thrig ( 36791 )

        "The supersonics are comingas surely as tomorrow. You will be flying one version or another by 1980 and be trying to remember what the great debate was all about." -- Najeeb Halaby, administrator, FAA.

        Uh yeah. About that.

        • Hahaha, that's like the opposite of that patent office guy circa 1900 who said that everything that could be invented had already been invented.

          • that quote is a myth; the guy actually said more along the lines of so many new things have been invented that he wouldn't be surprised if there were less new inventions in the future. which is a far cry from saying nothing new would be invented.

    • by PPH ( 736903 ) on Sunday May 17, 2015 @12:14PM (#49711375)

      Think about it, the total energy of all the shock and sonic boom is equal to amount of jet fuel burnt.

      Um, there's a lot of air being heated as well. In fact, that's the point.

      Or 54 kilowatt, or 54,0000 joules/sec.

      More like 54 * 10^6 joules/sec

      Our eardrums and instruments are sensitive enough to pick up the sonic boom over 10mph wind, but thats about it.

      Go back and crank in that 10^3 factor. It's not that quiet. But then again, since our ears and perception are logarithmic, it's not that bad compared to other sounds.

      It's also a function of altitude. If you can keep supersonic aircraft at or above 60,000 feet (and there are reasons other than noise for doing so), the shock wave energy is spread out over a greater area and attenuated.

      • Thanks for the correction. I missed it by a factor 1000 in power estimate. But I also lowballed the area by orders magnitude. Plane at 6 miles altitude, sonic boom energy is spread over a conical surface of base radius 10 km, area of at least 300 sq km. Wind energy goes as the cube of velocity, (squared in the kinetic energy term, and linear in the mass flow rate term). So at most it will be compared to a breeze of 12 or 13 mph rather than 10. But that is about all.

        Still feeling like a chump for missing t

    • Also the sonic boom issue was more FUD by Boeing, Douglas and Lockheed than the real issue. Back in the 80s, before the oil crisis, these companies wanted to stop British Aerospace and Aerospatiale from establishing a bridgehead at the luxury travel sector using Corcorde and its derivatives. But thankfully the Arab oil shock stopped Concorde.

      Out of curiosity, how old are you? I was a kid in the 1970s. 1970s jet engines were LOUD. When we were playing during recess and a jet plane passed overhead at 30,0

      • I enjoyed my very first hangover on an early morning flight on a 727 "Whisper Jet". Whisper my ass...

    • Thanks for all your calculations, but you entirely neglect auditory acoustic response issues, or the fact this energy is coming exclusively in rapid rise impulses.

      There is more direct information in this readily available [nasa.gov]. We read here that the
      "Concorde's sonic boom noise level was 105 PLdB. The PLdB that researchers believe will be acceptable for unrestricted supersonic flight over land is 75, but NASA wants to eventually beat that and reach 70 PLdB."
      The measure PLdB is "perceived level of decibels" whi

    • Your prodigious display of math is all for naught since you've essentially proved 1=2.

      I grew up in the early 60's when sonic booms were part of the background along with Duck and Cover. Nuclear war was just around the corner, or so we thought, and jets routinely generated sonic booms. Sometimes they'd sound like distant thunder and other times they'd rattle the house. Those were far louder, and more objectionable, than your putative 10 mph breeze.

      Thankfully, they tapered off towards the end of the 60's as t

  • by TheRealHocusLocus ( 2319802 ) on Sunday May 17, 2015 @10:23AM (#49710643)

    âoeOur team of experts will investigate how best to show this to pilots in the cockpit and develop guidance to most effectively modify the aircraftâ(TM)s flight path to avoid populated areas or prevent sonic booms.

    Yes. On Sunday it will do this. But Monday thru Saturday this technology will be used to test methods for waging Cymatic Warfare [google.com]... in which fighter planes slave their autopilots to a central computer that flies them in passes towards a target zone from several vectors, such that the sonic boom interfaces-to-ground converge at the same instant. We have yet to see what might happen as standard building materials are subject to this type of harmonically amplified sonic energy. By Saturday afternoon we'll know.

    Because there is no such thing as a single-use technology.

  • About 10 years ago or so.

  • There was a breakthrough a few years back where they found how to prevent the bow shock from forming in the first place. Did that die in R&D?
  • A device in the cockpit to tell the pilot where to go, so as to minimize sonic boom impact? This is a one-time job, map out good regions to fly through, done.

What sin has not been committed in the name of efficiency?

Working...