[roc-chat] Re: Interested in Sonic Boom Sound

  • From: Lakestake Rocketry <lakestake@xxxxxxxxx>
  • To: roc-chat@xxxxxxxxxxxxx
  • Date: Thu, 14 Jun 2012 18:18:24 -0700

Kurt, Google "speed of sound".  ;)

A pop heard half a second after burnout at an average temperature of 25
degrees C travels at approximately 346m/sec.

If the event occurred at a altitude of 340 meters the pop would have
happened 1/2 second before burnout and been heard half a second after (give
or take the spedd of light).  If burnout was higher it happened even

 On Jun 14, 2012 6:08 PM, "Kurt Gugisberg" <kurtgug@xxxxxxxxxxxxx> wrote:

> Richard, I heard it too.  Seemed to me it was shortly after burnout which
> makes it even more mysterious.  I was watching the flight and, as far as I
> can visualize it,  the burn ended and and half second or more later, the
> pop.
> Kurt
> -----Original Message-----
> From: Richard Dierking **
> Sent: Jun 14, 2012 8:49 AM
> To: roc-chat@xxxxxxxxxxxxx
> Subject: [roc-chat] Re: Interested in Sonic Boom Sound
> Ok, glad that someone else heard this Mike!  And yes, this sounds like a
> very good explanation.  I was a sharp pop and that's what surprised me.  Do
> you know who's rocket it was?  Just wondering if there's video out there.
> Thank you,
> Richard
> On Thu, Jun 14, 2012 at 12:29 AM, Mike Riss <rockt_dude@xxxxxxxxxxxxx>wrote:
>> Richard,
>> I think I heard the same thing, and IIRC, I was standing in the safety
>> zone at the time.  Seemed like it was towards the end of the motor burn.
>> It sounded pretty sharp to me.  I was thinking it was that "liner getting
>> expelled" that usually gets thrown out as an explanation for that type of
>> sound.
>> Mike
>> --- On *Wed, 6/13/12, Richard Dierking <richard.dierking@xxxxxxxxx>*wrote:
>> From: Richard Dierking <richard.dierking@xxxxxxxxx>
>> Subject: [roc-chat] Interested in Sonic Boom Sound
>> To: roc-chat@xxxxxxxxxxxxx
>> Date: Wednesday, June 13, 2012, 8:20 AM
>> During ROCstock after I was doing some maintenance on one of the back
>> pads and was walking away, a rocket was launched.  It was about a 4"
>> diameter, and had a large enough motor to get it going *fast*.  During
>> the flight, I definitely heard a "pop" but it didn't coincide with any
>> event I saw on the rocket.  I thought that a sonic boom could only be heard
>> if the cone created by the disturbance passed by you.  So, what could this
>> have been?  I was thinking perhaps a sound generated by turbulence at the
>> base of the rocket?
>> Anyway, this is the first time I've heard this kind of sound and I wonder
>> if someone has video that includes this "pop."
>> Richard Dierking
> **
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