What is this sound?

[gatt]

If you stand a quarter of a mile or so from the threshold at PDX 28R, (or at
the cemetery at McCarran in Las Vegas, the incoming), you hear a windy,
howling sound that is so well defined it seems to take shape in the sky
after the larger jets have passed for touchdown.

Has anybody heard it? What is that? Our theory has always been that its
the wingtip vortices collapsing.

-c

[Jay Honeck]

> Has anybody heard it? What is that? Our theory has always been that its
> the wingtip vortices collapsing.

We've heard it, too. Only the big jets seem to make that noise.

It's very cool, almost creepy.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Pepperoni]

It may be the thrust reversing. I presume that the sound is very much
louder on cool humid nights. I lived south of Willow Run (YIP) for many
years, but on those humid nights I could even hear the jets from Detroit
metro (DTW?) which was much further away.

It could also be the sound echo off the steep sides of those rugged hills,
eh?


"gatt" > wrote in message
...
>
> If you stand a quarter of a mile or so from the threshold at PDX 28R, (or
at
> the cemetery at McCarran in Las Vegas, the incoming), you hear a windy,
> howling sound that is so well defined it seems to take shape in the sky
> after the larger jets have passed for touchdown.
>
> Has anybody heard it? What is that? Our theory has always been that its
> the wingtip vortices collapsing.
>
> -c
>
>

[Jay Honeck]

> It may be the thrust reversing.

Nah -- it's the vortices whistling and zipping, after the plane has passed.

It almost sounds like someone swinging a jump-rope through the air as fast
as they can whip it.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Bela P. Havasreti]

On Mon, 07 Jun 2004 20:33:30 GMT, "Jay Honeck"
> wrote:

>> Has anybody heard it? What is that? Our theory has always been that its
>> the wingtip vortices collapsing.
>
>We've heard it, too. Only the big jets seem to make that noise.
>
>It's very cool, almost creepy.

My vote?

It's got something to do with air building up in front of those large
cowling/nacelle inlets while the jets "glide" towards the airport
at flight-idle.

When the power comes back up, the aerodynamics in front
of the cowling(s) changes and the result is the sound you hear.

(that's my WAG anyway....).

Bela P. Havasreti

[gatt]

"Jay Honeck" > wrote in message news:9a5xc.

> > It may be the thrust reversing.
>
> Nah -- it's the vortices whistling and zipping, after the plane has
passed.
>
> It almost sounds like someone swinging a jump-rope through the air as fast
> as they can whip it.

That's exactly what it sounds like. It's truly awesome on a good, still
night. It's so crisp that it seems like you could almost see it, like a
tornado.

In high school, I used to take dates out Marine Drive to listen to it. Heh.
No, really, that's why we went there.

-c

[Jay Honeck]

> In high school, I used to take dates out Marine Drive to listen to it.
Heh.
> No, really, that's why we went there.

Mary and I drove out to the end of a runway at Mitchell International, in
Milwaukee, WI, just to listen and watch.

And that's all we really did.

*sigh* It's hell to get old...

;-)
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

[Kyle Boatright]

"gatt" > wrote in message
...
>
> If you stand a quarter of a mile or so from the threshold at PDX 28R, (or
at
> the cemetery at McCarran in Las Vegas, the incoming), you hear a windy,
> howling sound that is so well defined it seems to take shape in the sky
> after the larger jets have passed for touchdown.
>
> Has anybody heard it? What is that? Our theory has always been that its
> the wingtip vortices collapsing.
>
> -c

What you're hearing is the wingtip vorticies. A really powerful one sounds
like someone ripping a bedsheet in half.

[Wizard of Draws]

On 6/7/04 6:08 PM, in article aH5xc.18373$Sw.6071@attbi_s51, "Jay Honeck"
> wrote:

>> In high school, I used to take dates out Marine Drive to listen to it.
> Heh.
>> No, really, that's why we went there.
>
> Mary and I drove out to the end of a runway at Mitchell International, in
> Milwaukee, WI, just to listen and watch.
>
> And that's all we really did.
>
> *sigh* It's hell to get old...
>
> ;-)

Jay, you're younger than I am, and I'm not old.
I'm a grandfather six months now and I'm not old.
Old folks don't ride motorcycles like we do. (OK, maybe a Goldwinger can be
old) ;)
Old people don't pilot planes.

I haven't even hit middle age yet, let alone old.
--
Jeff 'The Wizard of Draws' Bucchino
Cartoons with a Touch of Magic�
www.wizardofdraws.com
www.cartoonclipart.com

[Michelle P]

Can you get a recording?
Michelle

gatt wrote:

>If you stand a quarter of a mile or so from the threshold at PDX 28R, (or at
>the cemetery at McCarran in Las Vegas, the incoming), you hear a windy,
>howling sound that is so well defined it seems to take shape in the sky
>after the larger jets have passed for touchdown.
>
>Has anybody heard it? What is that? Our theory has always been that its
>the wingtip vortices collapsing.
>
>-c
>
>
>
>

--

Michelle P ATP-ASEL, CP-AMEL, and AMT-A&P

"Elisabeth" a Maule M-7-235B (no two are alike)

Volunteer Pilot, Angel Flight Mid-Atlantic

Volunteer Builder, Habitat for Humanity

[David Johnson]

> What you're hearing is the wingtip vorticies. A really powerful one sounds
> like someone ripping a bedsheet in half.

My office used to be adjacent to the final approach to Rwy 7 at KSBA, and
I have observed this phenomenon on numerous occasions. Often a sound like
fabric being torn. There was a row of trees parallel to the approach, and
these would often be thrashed about violently when the vortices hit them.
There was also a corrugated steel "vanity wall" (to hide the air conditioning
equipment) on top of an office building - likewise parallel to the approach.
Often the vortex striking this structure would make a sound like it had been
hit with a sledgehammer.

I know that there are those hereabouts who will dispute this, but it is my
observation that airplanes with winglets produce more violent wingtip
vortices than those without.

David Johnson

[EDR]

In article >, David
Johnson > wrote:

> I know that there are those hereabouts who will dispute this, but it is my
> observation that airplanes with winglets produce more violent wingtip
> vortices than those without.

B757's and B767's are known for their violent votices; even the 10 mile
spacing mandated by the FAA is not always sufficient to keep trailing
aircraft from being bounced (especially light, GA aircraft).

[gatt]

"Michelle P" > wrote in message

> Can you get a recording?

GREAT idea! That's kind of a forehead slapper, actually.

-c

[Jim Fisher]

"gatt" > wrote in message
...
>
> "Michelle P" > wrote in message
>
> > Can you get a recording?
>
> GREAT idea! That's kind of a forehead slapper, actually.

Gotta be a directional deal. Your standard mic would suck.

I'd look forward to hearing that.

--
Jim Fisher

[Newps]

"EDR" > wrote in message
...
>
> B757's and B767's are known for their violent votices; even the 10 mile
> spacing mandated by the FAA

What 10 mile spacing? There isn't 10 mile spacing for any two aircraft.