Thermal mapping

Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?

Assuming this is not a troll-

In the spring I like to use 'controlled' burns in the
forests for this. I can spot the smoke from a long
way, and by examing the plumes try and figure out the
strongest lift areas. Depending on how high above
the fires I can use the smoke smell as an olfactory
vario.

Typically these burns are done with an unstable atmosphere
to keep the smoke from sitting low in an inversion.
Once fire season gets going again I don't venture
near the conflagarations, but sometimes watch them
from afar.


At 15:24 19 April 2004, John wrote:
Here is a thought:

Was in the back yard making thousands of soap bubbles
(Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the
entire airflow
pattern in the back yard....even a little ridge lift
over the glider
trailer!

Wonder if you could add a soap bubble machine to a
sailplane? Turn it
on when you first hit a thermal and a trail of bubbles
is created.
After one circle, just fly toward the highest bubbles
and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might
could add a
color die to enhance visibility further.

Any thoughts on this?

John wrote:

Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?

You should install a sound system and play this guy's music.
http://www.welkshow.com/welk.html
But maybe you could integrate a bubble generator with a pilot relief
system. Its already an over-board liquid dispensing system, plus you'd
have the added benefit of discouraging leachers, at least those that are
familiar with your system.
:-)

Seriously, I'd use dust or smoke. I suspect the airspeed would shred
all but the smallest bubbles. Also, would enough bubbles persist long
enough to be seen? I do think visibility of bubbles would be the
biggest problem. Can you make bubbles with glitter in the solution? Or
dispense with the bubbles and just funnel the glitter out the vent
window. Hmm, sink rate is probably more than the glider's so it would
only work in a strong thermal. Also could clog the pitot system.


Shawn

"John" wrote in message
om...
Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?

Sounds maybe a little silly but it's sound thinking. Way back in the 1960's
I worked for Paul McCready at a little company called Meteorology Research
in Pasadena, California. One of my projects was to develop techniques to
map boundary layer turbulence.

We had made the same observation you did that soap bubbles trace airflow
very well. The first idea was to generate a bunch of bubbles, film them
with a pair of carefully calibrated movie cameras to get 3D data and then
analyze the film to plot the individual bubble trajectories. We thought we
could do a lot of interesting science with this data. (With the Lawrence
Welk TV show the rage, you can imagine the reputation this project quickly
developed - Welk was a band leader who used soap bubbles on his set to
highlight his "champagne music")

There were several problems. First, soap bubbles don't last very long -
maybe 20-30 seconds outdoors. (It seems UV degrades the soap films.)
Second, even with dye in the soap solution, bubbles are nearly invisible.
We tried filling them with colored smoke which reduced the average bubble
lifespan to about a second.

Tackling the bubble half life problem head on, I sought the help of some
chemists at CalTech who recommended adding polyvinyl alcohol to the bubble
solution. With PVA in the solution, a solid PVA film formed as the PVA was
polymerized by UV. The PVA+soap film seemed to be pretty gas tight and the
bubbles lasted a long time, but now they were heavy and quickly sank to the
ground.

Back at the drawing board, we dreamed up a modified bubble machine that
allowed the introduction of a carefully controlled amount of helium. With
this device pouring out bubbles, we could adjust the helium needle valve
until the bubbles showed neutral buoyancy. Now the bubbles traced the
airflow streamlines perfectly, we just couldn't see them very well and the
cameras didn't see them at all. Welk wasn't impressed.

Now we were delving into bubble optics. We knew that tiny glass spheres
would reflect light back to the source since that is what is used in
reflective paint on highway signs. Would bubbles do the same? Yes, but
altogether too well. The little glass spheres in reflective paint are
deliberately flawed. Our bubbles were perfect so they reflected a
searchlight beam directly back into the searchlight. If you were standing
next to the searchlight, you saw no reflections.

Now we built a camera mount with a huge beamsplitter so the cameras could
look right down the axis of the searchlight beam. Success! Our little
bubbles shown like stars tracing every little twist and turn of the airflow.

So here's the scene, high noon in downtown Pasadena with a couple of rented
Hollywood carbon arc searchlights, 35mm movie cameras and billions of
bubbles drifting around the buildings. It took several hours and the
company attorney to convince the authorities we weren't filming a movie and
didn't need a permit to do so.

We moved the project to the desert. It expanded from bubbles to Mylar
balloons, dozens of cameras and produced mountains of data. Unfortunately,
the IBM 360 punch card computer we used wasn't up to the task of analyzing
all the data. Last I heard, the data were still being re-analyzed by each
new generation of supercomputer.

So, would your idea work? I proved it would but all that heavy gear will be
pretty hard to get into a glider. Throwing out bits of toilet paper
probably works better. Hmmm, Lets see.....what would a toilet paper
dispensing machine look like...

Bill Daniels

This is not my idea but it sounds pretty good to me. "Doug" at Texas Soaring
Association (TSA) folds up TSA tow tickets so that they have two helicopter
blades and a body. As kids, we used to do this and throw them in the air and
watch them rotate and disappear in a thermal or rotate to the ground. When
"Doug" finds a thermal he throws a few of these folded helicopter tow
tickets out the vent window. They tend to go to the core of the thermal and
he follows them up. Don't anyone report "Doug" for excessive use of TSA tow
tickets or I will be in big trouble.

Hoping to center the thermal,
Bob Kibby "2BK"


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"John" wrote in message
om...
Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?

So, would your idea work? I proved it would but all that heavy gear will be
pretty hard to get into a glider. Throwing out bits of toilet paper
probably works better. Hmmm, Lets see.....what would a toilet paper
dispensing machine look like...

Bill Daniels



Someone beat you to it. Ted Teach had a 1-26 with a toilet paper
dispensing mechanism in the turtledeck. It was a little trapdoor with a
cutting edge. Open the door and toilet paper unrolled into the
slipstream. Close the door and it severed the paper. Repeatedly opening
and closing the door supposedly dispensed tp chaff to be followed as a
thermal marker. Teach's 1-26 also had a reprofiled nose and canopy and
doors that enclosed the landing gear (retractable gear being against the
rules in 1-26 racing. Mark Connor later had this 1-26 and was undoing
all the "Teachisms" on it.


People in this sport tend to be inventive. Wierd, but inventive...

"Bubbles, toliet paper, and bent tow tickets seem to center thermals by
themselfs. Free flight model airplanes do a good job of centering thermals
by themself. Ever consider what might happen if we just trimed out our
sailplanes and kept our hands off of the controls?

Duane

Duane Eisenbeiss wrote:

"Bubbles, toliet paper, and bent tow tickets seem to center thermals by
themselfs. Free flight model airplanes do a good job of centering thermals
by themself. Ever consider what might happen if we just trimed out our
sailplanes and kept our hands off of the controls?

How do we know they are centered? All I knew is the model was going up,
but I didn't know if it would do better in a different location.

I know just flying steady circles with the least amount of adjustment
needed to maintain attitude doesn't work well for me!

--
-----
change "netto" to "net" to email me directly

Eric Greenwell
Washington State
USA

(John) wrote in message . com...
Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?


This has been tried on and off for more than 50 years.
Popular markers were baloons, toilet paper, and most recently
published a bunch of years ago, newspaper.
Harry Senn found that newspaper was about what it took to be able to
see. Soaring had a very funny article on this experiment with classic
cartoon with it.
Reality- it doesn't work in the real world.
UH

How about throwing dollar bills out the canopy sliding window? That would
be a more direct way of wasting money on soaring and would also attract non
fliers to the sport.


"John" wrote in message
om...
Here is a thought:

Was in the back yard making thousands of soap bubbles (Mr. Bubbles)
for the baby. Slight breeze. Clearly could tell the entire airflow
pattern in the back yard....even a little ridge lift over the glider
trailer!

Wonder if you could add a soap bubble machine to a sailplane? Turn it
on when you first hit a thermal and a trail of bubbles is created.
After one circle, just fly toward the highest bubbles and that is
where the thermal's core is.

I could see the bubbles about 200 feet away, but might could add a
color die to enhance visibility further.

Any thoughts on this?