Visible wingtip vortex!

Morgans wrote
A great example of this is when the space shuttle lands, particularly at
Edwards (at KSC it tends to be humid so water vapor forms in the
vortices
and masks the refraction). I've noticed it a few times and it is mainly
visible in video pointed right down the runway. Super high wing loading,
I
would guess.

I had always thought that was mainly due to the fact that the air coming
off
the bottom of the wing was hot as **** from re-entry. Perhaps some of
both?
--
Jim in NC


The effect only seems to be visible where the wingtip vortices would be, so
my guess would be that it's at least mostly due to them. As for the tiles
being as hot as ****, I don't think it's unusual for the ground support guys
and even the crew to wander around the shuttle not long after landing, even
touching the tiles, so I doubt they're still too hot. The tiles work by
storing the energy of re-entry within the material without raising their
temperatures too much. At the aerodynamic surface of the tiles the
temperature does get up into the thousands of degrees due to the shock
heating, but by the time the shuttle touches down they've likely cooled to
somewhat just cooler than ****.

But those are just my thoughts and possible unreliable memories of photos
and video. I hope someone corrects me if I'm wrong.


-Tony "I'm not an aerospace engineer yet but I play one on TV" Goetz

"Tony Goetz" wrote

As for the tiles
being as hot as ****, I don't think it's unusual for the ground support
guys
and even the crew to wander around the shuttle not long after landing,
even
touching the tiles, so I doubt they're still too hot.

by the time the shuttle touches down they've likely cooled to
somewhat just cooler than ****.

chuckle You are most likely right. I remember seeing people pick up a
cube of tile material, just a few seconds after they came out of a furnace,
glowing red hot. Amazing stuff, for sure.

--
Jim in NC

On Mon, 24 Oct 2005 21:34:59 GMT, "Tony Goetz"
wrote:

A great example of this is when the space shuttle lands, particularly at
Edwards (at KSC it tends to be humid so water vapor forms in the vortices
and masks the refraction). I've noticed it a few times and it is mainly
visible in video pointed right down the runway. Super high wing loading, I
would guess. I searched for a while but could only come up with one decent
video showing the phenomena. Pictures don't really demonstrate it. This
video is in quicktime *.mov format, so my apologies if you can't view it.

http://www.fotosearch.com/comp/FIL/FIL101/EV0116.mov

The physics of it are just those of compressible flow. Change in density
leads to change in the index of refraction of the gas. Visible, as someone
else said, via the Schlieren optical system often used in
transonic/supersonic wind tunnels. I've seen such a setup in action at the
supersonic tunnel at my school. Pretty cool stuff.

http://www.ae.su.oz.au/aero/super2d/ssflow3.html
http://web.mit.edu/edgerton/people/v...schlieren.html


-Tony Goetz
Rocket scientist in training.


Yep, that's it, except the one from the AA5 was tiny. It seemed to be
no more than a 2" cone.

Notice how you can't see it at ALL until it gets down into line of
sight along the vortex. Same as my flight.

Guys, I'm gonna get video...it will be on the site. It's just amazing
looking.


Bill Strahan
------------
Find a new reason to fly
www.adventurepilot.com

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"Bill" wrote

Yesterday I was flying back from a weekend camping trip, and came up
behind my friend in his AA5. I started getting up close, and was
feeling the effect of the vortex off his right wingtip. I reached the
point that I had my ailerons deflected almost 50-60% to the right just
to stay level, when I suddenly SAW the vortex hitting my windshield!

I know if I heard this description I would say it was bull****. But I
saw it, as did my passengers. It was a tube of swirling distortion,
dropping down off his wingtip and then coming back to us.

You are the first I have ever heard describe this. Interesting. I would
think that there was a little moisture component along with the density and
diffraction, but perhaps not.

They say the late NASCAR race car driver, Dale Earnhart, could see "the
draft." His success at the highest speed tracks, where the draft was the
most important, would seem to make you think that he had something extra
working for him. Your account makes me give more credence to that legend,
now. Thanks for posting.
--
Jim in NC