Additionally, Rick said that he could see standing waves of pure sound
energy in the blades of grass on the hillside, I believe he mentioned 3 Hz
and the human abdomen resonates at 7Hz, or visa versa. And Yes, a single
large nozzle generates much lower frequencies than multiple nozzles of
equivalent total thrust and exhaust velocity has a bearing on SPL, Also
higher exhaust velocities equates to louder engines and jets with
afterburners are far louder than w/o AB.
On Mon, Apr 27, 2020 at 4:50 PM Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
Ears are perishable, yes. Ears and lungs. Don't squander their capacity;
you'll need them later.
On 4/27/2020 3:17 PM, Troy Prideaux wrote:
Ken, I don’t know if you ever knew/met Bill Bullock?... but one post of
his I’ll never forget:
Envision an OLD man slowly mounting a well-worn soapbox, and then:
Things I have heard:
An Atlas A-2 lifting off just 380 feet away...in the open,
A Navaho on liftoff from 550 feet away...in the open,
Multiple Snarks launched with JATO packs from less than 100 feet.
Bullpups from 30 feet,
Over 50 Liquids, Solids and Hybrids from 12 feet,
105 Howitzers as I slept under the carriage all night,
300 Win. Magnums fired 300-5-- rounds per day 5 days a week forever,
11" (bore) X 14" (stroke) Superior Engines close up with no exhaust
suppression,
J-54`s less than 10 feet away,
350 hp Lycoming on an airboat with no suppression,
etc..., etc...
WHAT I WISH I COULD HEAR:
The wind through a pine tree,
The wings of a Wood Duck settling in for the night,
What my wife whispered to me during Church this morning,
"Real" crickets at night,
When my grandsons whisper "I love you, Grandpaw!" in the restaurant,
What a friend says across the room at a party,
etc...,etc...,etc...
Now envision an OLD man slowly descending from his well-worn soapbox
in his almost complete personal silence. Anyone care to ask me my opinion
on
the subject?
Respectfully,
Bill Bullock
*From:* arocket-bounce@xxxxxxxxxxxxx [mailto:arocket-bounce@xxxxxxxxxxxxx
<arocket-bounce@xxxxxxxxxxxxx>] *On Behalf Of *roxanna Mason
*Sent:* Tuesday, 28 April 2020 2:35 AM
*To:* arocket@xxxxxxxxxxxxx
*Subject:* [AR] Re: rem0ved from l1st?
On that Soyuz video, makes me wonder what actually is the 'safe'
acoustical distance from a large rocket/engine.
I knew a guy who witnessed F-1 engine tests at RPL/Edwards AFB, my old
stomping grounds but post Apollo, and he said at a 1/4 mile he was bouncing
on the ground he was standing on. Immediately after the test he felt tingly
almost euphoric then awhile later got nauseated. W/O empirical data it's
hard to quantify SPL when a water cooled flame bucket is involved but with
a launch you get the whole gambit from water to being inside the cone of
max decibels. That guy at the Soyuz launch looked like he was within that
zone, The camera and the guy didn't even shake. Such privilege/fun.
On Sun, Apr 26, 2020 at 2:20 PM Henry Vanderbilt <
hvanderbilt@xxxxxxxxxxxxxx> wrote:
I edited away from "Unsubscribed?" as my original title for that exact
reason. Got no error messages on my three tries with "removed" in the
title though - one fail, two posts. So freelists may be a tad
inconsistent. But hey, the price is right and it mostly works.
Nope, no mailbox overflow. Nothing in the spam folder either. Dirtlink
was apparently hosting too many spammers at one point and messages
originating there would occasionally get blocked en route on narrowly
specific routes, but not in years, and not for incoming. Auto unsub with
errors does seem more likely though than an intersection between the
(significant) set of people I sometimes irritate, the (presumably very
small) set of people with file-access to freelist, and the (hopefully
extremely small) list of people who'd do something nefarious with that
access.
I skimmed through the archives, and yes, a slow couple weeks. Interesting
to know teflon will burn in supercrit oxygen or with hot magnesium, useful
to know the combustion products are hideously toxic so don't mess with it.
A few things about Apollo 13 and Surveyor I didn't know. And whoever took
that vid of a Soyuz launch was (very) roughly 150-200 meters away, from the
(very) roughly half-second (maybe a bit more, but well under a second -
roughly half a "one-missouri") delay between the visible main-engine start
and the sound. I'd have to figure out a way to view the vid on a
frame-by-frame basis, with visualization of the audio amplitude, to get
more precise, and I won't bother because it wouldn't change the basic
conclusion: The person taking the video had one hell of a front-row seat!
Henry
On 4/26/2020 1:13 PM, Ben Brockert wrote:
(Replied earlier but got an error message because the list thinks the
subject looks like a remove request)
Is your mailbox near full, or any other reason emails to you would bounce?
Fairly common for list software to automatically unsubscribe accounts with
errors.
You haven’t missed anything. Maybe Bruno will post the cool thing he
posted to Twitter today.
On Sunday, April 26, 2020, Henry Vanderbilt <hvanderbilt@xxxxxxxxxxxxxx>
wrote:
2nd try, my first follup attempt still hadn't shown up after twenty
minutes, either in the archive or emailed back to me... FWIW, I managed to
set and unset vacation mode just before this retry, so at least that part
of freelists still thinks I'm subscribed.
Retry: OK, as I thought, unsub security is solely via email confirmation.
So I changed my email password to be on the safe side. But it was a
relatively new password before that, fairly strong, and I had no other
reason whatsoever to think it was compromised.
And, a clue: First time I resubscribed today, I did not see the freelists
ToS agreement page. Second time, after explicitly unsubscribing, when I
resubscribed I did see the ToS agreement page.
Which suggests to me that something may have happened to my entry on the
actual freelists arocket emails list, without altering my previous record
of consenting to the ToS. A bug? Or something. Just sayin'.
Henry
On 4/26/2020 12:04 PM, Henry Vanderbilt wrote:
Interesting. Sometime between 4/10/20 22:34 and 22:36, I was unsubscribed
from the list - again. Second time in two weeks, the first being
midmorning MST of 3/27. I don't *think* I'd done anything flagrant in
either case, and I never heard from list management either time, so I'm
beginning to think someone may be messing with me.
Or is there some known issue where this just happens - has anyone else
been hit?
Gonna go run through the unsubscribe procedure to see what security's on
it, then resubscribe and go look into what that may have said about local
security issues...
Henry
