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

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...

"Wallace Berry" wrote in message
...


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.

In all seriousness, the bubble experiments produced some very good insights
in low level convective airflow. Neutrally buoyant bubbles have no
aerodynamic qualities of their own so if they are seen to move, it is
because airflow is pushing them. Bits of paper and other debris do have
some aerodynamic qualities so the data is corrupted. Up to that point there
were several studies that used smoke, but that can't be analyzed
numerically. Discrete bubbles provided a means to measure speed and
direction of airflow in 3D to high precision.

Later, larger scale experiments with Mylar balloons were even more
interesting. First pairs would be released and tracked for many miles by
radar. Eventually, large numbers of these balloons were released
simultaneously along a crosswind line in thermic conditions and watched by
radar as they traced out thermal streets.

Today, most work of this kind is done with LIDAR (Laser Radar) which can
track naturally occurring tiny aerosols of pollen and dust revealing the 3D
structure of airflow with great precision over a large area in real time.

Now, putting a LIDAR in a glider WOULD be interesting.

Bill Daniels

Actually for thermal marking purporses smoke would work pretty fine. But I
don't know any smoke machine which is small enough to fit to the glider and
which is controllable. For aerobatics they just fit smoking cartridges that
burn to the end after ignition, but thermal marking needs some repeatable 2
sec buffs of somke.
There's another problem with bubbles. The only reasonable place to put it is
on top of the rear fuselage. But then you spill the vertical fin with wet
bubbles and this harms your L/D.

Regards,
Kaido



"Bill Daniels" wrote in message
news:t6ahc.33650$ru4.33232@attbi_s52...

"Wallace Berry" wrote in message
...


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.

In all seriousness, the bubble experiments produced some very good
insights
in low level convective airflow. Neutrally buoyant bubbles have no
aerodynamic qualities of their own so if they are seen to move, it is
because airflow is pushing them. Bits of paper and other debris do have
some aerodynamic qualities so the data is corrupted. Up to that point
there
were several studies that used smoke, but that can't be analyzed
numerically. Discrete bubbles provided a means to measure speed and
direction of airflow in 3D to high precision.

Later, larger scale experiments with Mylar balloons were even more
interesting. First pairs would be released and tracked for many miles by
radar. Eventually, large numbers of these balloons were released
simultaneously along a crosswind line in thermic conditions and watched by
radar as they traced out thermal streets.

Today, most work of this kind is done with LIDAR (Laser Radar) which can
track naturally occurring tiny aerosols of pollen and dust revealing the
3D
structure of airflow with great precision over a large area in real time.

Now, putting a LIDAR in a glider WOULD be interesting.

Bill Daniels

Perhaps NASA will help us with thermal locating. Quoting from a CNN article
currently at http://www.cnn.com/2004/TECH/space/0...vil/index.html
:
Dust particles in a devil become electrified because they rub against one
another. It's like shuffling your feet across the carpet, the researchers
explained. But they figured the positive and negative particles would be
evenly mixed in a dust devil, keeping the overall electrical charge in
balance.

Instead, it turns out smaller particles tend to gain negative charge, and
the wind carries them higher.

Heavier, positive particles remain nearer the surface. The separation of
charges creates a giant battery. And because the particles are in motion, a
magnetic field is generated by the moving electrical charges, the
researchers explained.

They don't yet know for sure what to expect on Mars.

If dust on the red planet comes in a variety of sizes and compositions, as
expected, then dust devils there ought to be similarly electrified, the
scientists said. NASA could equip a future Mars landing craft with an
instrument to detect a dust devil's electric and magnetic fields.

Mike Koerner

"iPilot" wrote in message
...
Actually for thermal marking purporses smoke would work pretty fine. But I
don't know any smoke machine which is small enough to fit to the glider
and
which is controllable. For aerobatics they just fit smoking cartridges
that
burn to the end after ignition, but thermal marking needs some repeatable
2
sec buffs of somke.
There's another problem with bubbles. The only reasonable place to put it
is
on top of the rear fuselage. But then you spill the vertical fin with wet
bubbles and this harms your L/D.

Regards,
Kaido



"Bill Daniels" wrote in message
news:t6ahc.33650$ru4.33232@attbi_s52...

"Wallace Berry" wrote in message
...


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.

In all seriousness, the bubble experiments produced some very good
insights
in low level convective airflow. Neutrally buoyant bubbles have no
aerodynamic qualities of their own so if they are seen to move, it is
because airflow is pushing them. Bits of paper and other debris do have
some aerodynamic qualities so the data is corrupted. Up to that point
there
were several studies that used smoke, but that can't be analyzed
numerically. Discrete bubbles provided a means to measure speed and
direction of airflow in 3D to high precision.

Later, larger scale experiments with Mylar balloons were even more
interesting. First pairs would be released and tracked for many miles
by
radar. Eventually, large numbers of these balloons were released
simultaneously along a crosswind line in thermic conditions and watched
by
radar as they traced out thermal streets.

Today, most work of this kind is done with LIDAR (Laser Radar) which can

track naturally occurring tiny aerosols of pollen and dust revealing the
3D
structure of airflow with great precision over a large area in real
time.

Now, putting a LIDAR in a glider WOULD be interesting.

Bill Daniels

If anyone has free funds to play around with tinyfogger
http://www.tinyfogger.com/us/tiny-fogger.html I'd be interested in hearing about the results later
on. Funds needed are in range of $1200.

On Mon, 19 Apr 2004 16:39:49 GMT, "Bill Daniels"
wrote:

[snip]
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...

A building with a sign saying "Ziff-Davis"?

rj