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Breaking the sound barrier by air, by land, and in free fall

  • 15-10-2015 12:48am
    #1
    _Tombstone_
    Closed Accounts Posts: 3,006 ✭✭✭


    http://arstechnica.com/cars/2015/10/breaking-the-sound-barrier-by-air-by-land-and-in-free-fall/
    On October 14, 1947, high above California's Antelope Valley, Charles "Chuck" Yeager became the fastest man alive. That day Yeager—an Appalachian farm boy-turned-fighter ace—flew an experimental rocket plane called the Bell X-1 through the sound barrier and into the history books. Fifty years and one day later (and only about 500 miles due north), another fighter pilot—RAF Wing Commander Andy Green—equaled Yeager's feat but on four wheels. Thrust SSC was the name of his ride, and it made Green the fastest man on Earth. It's a title he still holds.
    The speed of sound—otherwise known as Mach 1 after an Austrian physicist—varies depending upon the medium through which that sound is passing. On a warm day at sea level, it's about 768mph, or 343.2m/sec if you prefer to think in SI units. Throughout the 17th century, scientists in England and France worked to calculate the speed of sound, getting ever closer before William Derham got there—or thereabouts—in 1709. Derham used a telescope, a pendulum, and his church tower in Upminster (now a far suburb of London) to arrive at the answer by observing the interval between seeing a rifle flash and hearing its crack. It would be more than 200 years before a human could attempt to travel that fast, however.

    The first challenger would have to wait for World War II.....


Comments

  • #2
    St. Leibowitz
    Registered Users, Registered Users 2 Posts: 349 ✭✭St. Leibowitz


    Interesting.

    I've often wondered something about sonic booms. Do they only occur during the transition from to and from supersonic speed, or do they happen during supersonic flight ??

    I remember hearing a double boom on several occasions when in Wicklow during the 70's. It only happened when weather conditions were right, and sounded similar to both barrels of a double barrel shotgun being fired in very quick succession, but was really, really deep, and very distinctive. Apparently, it was Concorde going supersonic down around the Bristol Channel. Was this the only boom, or if you were on a ship mid-Atlantic and it passed over, would you hear a boom there also ?


  • #3
    _Tombstone_
    Closed Accounts Posts: 3,006 ✭✭✭_Tombstone_


    St. Leibowitz wrote: »
    Interesting.

    I've often wondered something about sonic booms. Do they only occur during the transition from to and from supersonic speed, or do they happen during supersonic flight ??

    I remember hearing a double boom on several occasions when in Wicklow during the 70's. It only happened when weather conditions were right, and sounded similar to both barrels of a double barrel shotgun being fired in very quick succession, but was really, really deep, and very distinctive. Apparently, it was Concorde going supersonic down around the Bristol Channel. Was this the only boom, or if you were on a ship mid-Atlantic and it passed over, would you hear a boom there also ?

    http://www.boards.ie/vbulletin/showthread.php?p=95850321

    Boom Thread may answer some of your questions.


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