Any sailplane pilots?

My cousin just bought a Schweizer 1 36 sailplane.

We took it to the airport today where he is going to hanger it today, and
put her together so the FAA could give the stamp of approval with the
airworthiness certificate.

Looks like the sailplane could be alot of fun.

I have never been around them before.

Just wondering how many guys fly gliders...

Have you checked out rec.aviation.soaring ?

--
--
=-----
Good Flights!

Cecil
PP-ASEL

Check out my personal flying adventures complete with pictures and text at:
www.bayareapilot.com

"I fly because it releases my mind from the tyranny of petty things."
- Antoine de Saint-Exupery -

"We who fly, do so for the love of flying. We are alive in the air with
this miracle that lies in our hands and beneath our feet"
- Cecil Day Lewis -

On Sun, 21 Dec 2003 06:00:30 GMT, "Chuck" wrote
in Message-Id: . net:

My cousin just bought a Schweizer 1 36 sailplane.

I've some experience with the Schweizer 1-26. It had an L/D of 30
IIRC. Do you know the L/D of the 1-36?
http://www.dfrc.nasa.gov/Gallery/Photo/Schweizer-1-36/

We took it to the airport today where he is going to hanger it today, and
put her together so the FAA could give the stamp of approval with the
airworthiness certificate.

Looks like the sailplane could be alot of fun.

It is a contest between the pilot and mother nature. The idea is to
spend more time in rising air than sinking air, and thus gain and
sustain altitude. The pilot must mentally visualize the movements of
the air masses in his vicinity, due to convective and orographic
vertical displacement, solely through interpreting instrument
indications and seat-of-the-pants cues.

The spectrum of soaring meteorological conditions ranges from flat
(little or no vertical movement of the air mass) to booming. During
the latter, the pilot is nearly unable to prevent his ship from
rising; it's like having a motor. On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.
Because this can require banks in excess of 60 degrees, occupants ware
a parachute. Such long, constant high-G circling can adversely affect
passengers of multi-place sailplanes, but the pilot will find it
exhilarating. The sport of soaring adds another dimension to similar
naturally powered sports such as sailing, surfing, and skiing...

I have never been around them before.

Just wondering how many guys fly gliders...


[newsgroup rec.aviation.soaring added]

Larry Dighera LDighera wrote:

I've some experience with the Schweizer 1-26.
It had an L/D of 30 IIRC.

L/D on the 1-26 is 23:1, same as the Schweizer 2-33 (2-place).

Do you know the L/D of the 1-36?

31:1

It is a contest between the pilot and mother
nature. The idea is to spend more time in rising
air than sinking air, and thus gain and sustain
altitude. The pilot must mentally visualize the
movements of the air masses in his vicinity,
due to convective and orographic vertical
displacement, solely through interpreting
instrument indications and seat-of-the-pants cues.

Great description!

BTW, on good days during thermal season, it is possible to climb w/o banking in
that extreme or needing a parachute. I climbed to 11K feet this summer in a
1-26 from a 2000-ft tow and was never banked more than 30 degrees ... and the
lift was still strong enough I could have continued, but didn't have oxygen.
Sometimes exposing more of the sailplane surface to the lift (shallow bank)
works as well or better, if you can do that and stay in the thermal ... depends
on the thermal(s) and you don't know until you get in it. Sometimes you fly
right out of it a few times before you figure out where you need to make your
circles.

Very, very fun.

--Shirley

On 21 Dec 2003 16:15:41 GMT, unicate (Shirley)
wrote in Message-Id: :

Larry Dighera LDighera wrote:

It is a contest between the pilot and mother
nature. The idea is to spend more time in rising
air than sinking air, and thus gain and sustain
altitude. The pilot must mentally visualize the
movements of the air masses in his vicinity,
due to convective and orographic vertical
displacement, solely through interpreting
instrument indications and seat-of-the-pants cues.

Great description!

Thanks.

BTW, on good days during thermal season, it is possible to climb w/o banking in
that extreme or needing a parachute. I climbed to 11K feet this summer in a
1-26 from a 2000-ft tow and was never banked more than 30 degrees ... and the
lift was still strong enough I could have continued, but didn't have oxygen.
Sometimes exposing more of the sailplane surface to the lift (shallow bank)
works as well or better, if you can do that and stay in the thermal ... depends
on the thermal(s) and you don't know until you get in it. Sometimes you fly
right out of it a few times before you figure out where you need to make your
circles.

Very, very fun.

--Shirley


I know what you mean. Here's a little story that illustrates your
point:


Cumulonimbus Clouds Possess Awesome Power!

Having just obtained my glider license, I was cruising the local area
around El Mirage Airport in the Antelope Valley, California. I was
flying solo in the Southern California Soaring Association club's
venerable SGS 2 33 two-place trainer. It was a sweltering, sunny,
summer day in the Mojave Desert. Lift seemed to be everywhere; it was
almost like flying an engine-powered aircraft. Mother nature's
horsepower was smooth and quiet. I could just cruise around wherever
a whim took me and still sustain a climb without having to circle in a
thermal.

After a while, I was beginning to approach cloud-base, nearly 12,000
feet M.S.L. It was magical to see the land spread out for a hundred
miles in all directions. I hadn't noticed that the day had over
developed. The rest of the desert was still brilliantly lit in the
summer sun. What a joy.

As the ragged bottom of the cloud reached down toward me, and thin
wisps of condensed vapor passed my canopy, I began to think about
descending. Reluctantly I lowered the nose. Airspeed increased, but
I was still going up. What a day! I applied the dive brakes /
spoilers, and lowered the nose some more. These big, double surface,
spoilers are very effective at preventing excessive speed from
building up, I thought. I've never had a chance to try this before.
Aiming the nose of the ship 30 degrees toward the ground, I was really
diving now. But, I was still going up! My rapture faded. Hey, this
is starting to get serious.

With the pitch attitude nearly 40 degrees and full spoilers extended,
I couldn't think of anything else that would cause the sailplane to
descend. If the cloud engulfed me, what would I do?

I had no electrical system or gyro instruments. Thoughts of
techniques to use the compass as a directional gyro by heading south
flashed through my mind as I started to enter the ominous dark gray
cloud that stretched out above me. I've heard that it's possible to
stay right side up with only needle, ball, and airspeed reference, but
compass, yaw string, and airspeed? Doubtful at best.

Full realization of the situation finally dawned on me. I was being
sucked into a thunder storm! The latent heat of condensation can
drive these billowing monsters up 60,000 feet into the stratosphere
where the temperature is MINUS 50 degrees F, and there's not enough
oxygen to sustain life my life! This was really an emergency
situation! I felt helpless. What could I do to get down?

Now I was frightened. In a lightweight ship with all that wing area,
how was I going to extract myself from this? I had never spun a 2 33
before. Perhaps this was the time to get some parachute jumping
experience! Panic was beginning to immobilize me, and my ascent
continued.

I've experienced panic before. It is a warning signal to calm
yourself and start thinking. It's hopeless. I'm going to be spat out
the top of the cloud as a frozen snow ball, or have to jump wearing
this old military-surplus chute.

Calmly, the basic physics I had been taught came to my rescue: Lift =
Weight, Thrust = Drag. I need more drag, I thought. Quickly, I
entered cross-control input and began to slip to increase the frontal
area that the ship presented to the slipstream, but I still continued
upward into mother natures tenacious grip. It was white all around me
now; I could only see the earth if I looked straight down.

Hmm, . . . There is an excess of lift. The lift vector is pointing
up, at the cloud, which now nearly fully enveloped me. I need to
point it someplace else! Yes! That's it! I immediately banked over
60 degrees and began a steep spiral descent. It worked! The
variometer needle finally pointed toward mother earth. Hallelujah!

Just as I landed at the home field and extracted my sweat drenched
body from the cockpit, the cold wind of the thunder storm's telltale
first-gust nearly took the ship. That Cu Nim wasn't done with me yet.
Lightening lit the black sky and thunder boomed almost simultaneously.
In the ensuing cloud burst, I was grateful for the assistance of a
couple of club members who helped me walk the ship to its mooring
spot. The rain felt good.

This was a close encounter with mother nature's awesome power. She
had tried to eat me alive, and driven me from her lofty realm back to
the ground, hurled bolts in my direction, roared her thunder at me,
threatened to send my ship careening into a ball of useless aluminum
foil, and finally drenched me to the skin in a deluge of disgust.
What a woman!

It was a lessen well learned. Never let a cumulonimbus sneak up on
you; they masquerade as an overcast cloud deck when they stalk you.

Larry Dighera
CP ASEL, IR, Glider


Copyright L. Dighera 1997

Larry Dighera wrote:


The spectrum of soaring meteorological conditions ranges from flat
(little or no vertical movement of the air mass) to booming. During
the latter, the pilot is nearly unable to prevent his ship from
rising; it's like having a motor. On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.
Because this can require banks in excess of 60 degrees, occupants ware
a parachute. Such long, constant high-G circling can adversely affect
passengers of multi-place sailplanes, but the pilot will find it
exhilarating. The sport of soaring adds another dimension to similar
naturally powered sports such as sailing, surfing, and skiing...

Just in case you might get the idea from Larry that we all have our
blood at our feet from G loads, note that _most_ us use more like a 30
degree bank (g load hardly noticeable after a few flights), and can go
up just fine!

And for _most_ of us, wearing a parachute doesn't have anything to do
with circling in thermals. They aren't required except in contests, but
most private owners end up with one for various reasons, and wear it all
the time (sort of like wearing a seat belt in a car). Clubs aren't so
likely to use them while flying their gliders.

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

Eric Greenwell
Washington State
USA

Larry wrote:

On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.

Why do you write "anticyclone" Larry. This would mean that all gliders would
circle righthanded to stay as close to the core as possible thereby using
the headwind of the thermal.
I have never found a meteorological reason to circle in a certain direction.
Most pilots circle lefthanded just because they were tought to do so in the
vicinity of their home field. However in x-country flights there is usually
no preference. In low situations the pilot usually circles in the direction
he feels most comfortable. Sometimes the gliders feels better when circling
to the right rather then to the left is my experience.

Karel, NL

"Eric Greenwell" schreef in bericht
...
Larry Dighera wrote:


The spectrum of soaring meteorological conditions ranges from flat
(little or no vertical movement of the air mass) to booming.

Eric Greenwell
Washington State
USA

On Fri, 26 Dec 2003 09:00:24 GMT, "K.P. Termaat" wrote
in Message-Id: :

Larry wrote:

On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.

Why do you write "anticyclone" Larry.

That was my recollection from my soaring experience in the early '70s.
However, it appears that the word 'cyclone' may have more correct now
that I have done some research:

The National Weather Service Glossary page here
http://www.wrh.noaa.gov/Phoenix/general/glossary/ has this to say:

ANTICYCLONE - A region of high atmospheric pressure around which
winds move in a clockwise direction in the northern hemisphere.
Generally associated with warm and dry weather

CYCLONE - An area of low pressure around which winds blow in a
counter-clockwise fashion in the northern hemisphere. Generally
associated with cool, wet and unsettled weather

On the other hand ...

This would mean that all gliders would circle righthanded to stay as close
to the core as possible thereby using the headwind of the thermal.

I'll defer to these sources:

http://www.rc-soar.com/tech/thermals.htm
Do thermals rotate?
They do, but not predictably. Even dust devils don't have a
preferred direction of rotation (see Stull, p.449). Thermals are
too small and too short-lived to be affected by the earth's
rotation (Coriolis force) or by the equator/pole thermal gradient.
Their rotation is determined by local terrain. Rotational velocity
in the core of a typical thermal is small compared to the vertical
velocity.


http://www.skynomad.com/articles/athermal10.html
THERMALS

Do Thermals Spin?
by Peter Gray

Of course, dust devils spin, so thermals probably do also, at
least when they're close to the ground. For many years, I was
convinced that dust devils rotated in random directions. However,
based on a few flights in northern Washington State, where I kept
more careful mental notes, I would guess that about 2/3 to 3/4 of
the dust devils there spin counterclockwise, in agreement with the
Coriolis Effect. Contrary to popular belief, the smaller-scale
equivalent, water going down a toilet or drain, is essentially
unaffected, and the rotation, if it is biased toward one spin
direction, is the result of the geometry of each such basin (check
it out for yourself!).

The dust devils formed by thermals seem to be just large
enough to be affected somewhat by the Coriolis Effect. If I have
the choice, I usually opt for circling against the dust devil's
rotation, most often to the right, in case this will produce a
better climb rate by reducing my circling ground speed, thus bank
angle and sinkrate.

However, when I have reversed direction several times in one
climb, I have rarely detected a significant advantage in one
direction. What little angular momentum thermals start with, they
seem to lose through drag in the surrounding air, and they
probably start with little spin anyway. As with water going down a
drain, very little spin momentum at a large radius can translate
to a rapid spin when the radius shrinks to that of a dust devil.

I have never found a meteorological reason to circle in a certain direction.
Most pilots circle lefthanded just because they were tought to do so in the
vicinity of their home field. However in x-country flights there is usually
no preference. In low situations the pilot usually circles in the direction
he feels most comfortable. Sometimes the gliders feels better when circling
to the right rather then to the left is my experience.

Karel, NL

Agreed. Circling direction is more often dictated by other gliders in
the thermal than meteorological phenomena and physics.

Thanks Larry for your interesting respons with your links to the articles.

As a matter of fact most members of our National Team (my son is one of
them) tend to circle to the right when low. They don't in effect know why.
They say, and I agree, that it usually feels better in getting up again. So
Peter Gray may be right in saying that most of the thermals have the
tendency to rotate to the left in the northern hemisphere, especially when
low when still having small diameters. Coriolis may be the cause then. Would
be interesting to know the experience in the southern hemisphere.

Talking about a drain and water brings me to the idea of telling that when
low and looking for a thermal I always try to locate small ponds in dry
areas. It looks to me that the water vapor rising from these ponds is an
excellent means of starting a thermal. Water vapor is lighter then air, so
it increases the boyancy of the air over the pond and off it goes. Starting
at about ground level, circling to the right may then generally be the
better option. Any experience with this Larry?

Karel, NL


"Larry Dighera" schreef in bericht
...
On Fri, 26 Dec 2003 09:00:24 GMT, "K.P. Termaat" wrote
in Message-Id: :

Larry wrote:

On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.

Why do you write "anticyclone" Larry.

That was my recollection from my soaring experience in the early '70s.
However, it appears that the word 'cyclone' may have more correct now
that I have done some research:

The National Weather Service Glossary page here
http://www.wrh.noaa.gov/Phoenix/general/glossary/ has this to say:

ANTICYCLONE - A region of high atmospheric pressure around which
winds move in a clockwise direction in the northern hemisphere.
Generally associated with warm and dry weather

CYCLONE - An area of low pressure around which winds blow in a
counter-clockwise fashion in the northern hemisphere. Generally
associated with cool, wet and unsettled weather

On the other hand ...

This would mean that all gliders would circle righthanded to stay as
close
to the core as possible thereby using the headwind of the thermal.

I'll defer to these sources:

http://www.rc-soar.com/tech/thermals.htm
Do thermals rotate?
They do, but not predictably. Even dust devils don't have a
preferred direction of rotation (see Stull, p.449). Thermals are
too small and too short-lived to be affected by the earth's
rotation (Coriolis force) or by the equator/pole thermal gradient.
Their rotation is determined by local terrain. Rotational velocity
in the core of a typical thermal is small compared to the vertical
velocity.


http://www.skynomad.com/articles/athermal10.html
THERMALS

Do Thermals Spin?
by Peter Gray

Of course, dust devils spin, so thermals probably do also, at
least when they're close to the ground. For many years, I was
convinced that dust devils rotated in random directions. However,
based on a few flights in northern Washington State, where I kept
more careful mental notes, I would guess that about 2/3 to 3/4 of
the dust devils there spin counterclockwise, in agreement with the
Coriolis Effect. Contrary to popular belief, the smaller-scale
equivalent, water going down a toilet or drain, is essentially
unaffected, and the rotation, if it is biased toward one spin
direction, is the result of the geometry of each such basin (check
it out for yourself!).

The dust devils formed by thermals seem to be just large
enough to be affected somewhat by the Coriolis Effect. If I have
the choice, I usually opt for circling against the dust devil's
rotation, most often to the right, in case this will produce a
better climb rate by reducing my circling ground speed, thus bank
angle and sinkrate.

However, when I have reversed direction several times in one
climb, I have rarely detected a significant advantage in one
direction. What little angular momentum thermals start with, they
seem to lose through drag in the surrounding air, and they
probably start with little spin anyway. As with water going down a
drain, very little spin momentum at a large radius can translate
to a rapid spin when the radius shrinks to that of a dust devil.

I have never found a meteorological reason to circle in a certain
direction.
Most pilots circle lefthanded just because they were tought to do so in
the
vicinity of their home field. However in x-country flights there is
usually
no preference. In low situations the pilot usually circles in the
direction
he feels most comfortable. Sometimes the gliders feels better when
circling
to the right rather then to the left is my experience.

Karel, NL

Agreed. Circling direction is more often dictated by other gliders in
the thermal than meteorological phenomena and physics.

In message , Eric Greenwell
writes
Larry Dighera wrote:


The spectrum of soaring meteorological conditions ranges from flat
(little or no vertical movement of the air mass) to booming. During
the latter, the pilot is nearly unable to prevent his ship from
rising; it's like having a motor. On an average day, a pilot will
spend a great deal of time attempting to "core" thermals. That
involves mentally visualizing the sailplane's position relative to the
thermal's vertical anticyclone column center, and guiding his
sailplane to circle as near to the center of it as he is able.
Because this can require banks in excess of 60 degrees, occupants ware
a parachute. Such long, constant high-G circling can adversely affect
passengers of multi-place sailplanes, but the pilot will find it
exhilarating. The sport of soaring adds another dimension to similar
naturally powered sports such as sailing, surfing, and skiing...

Just in case you might get the idea from Larry that we all have our
blood at our feet from G loads, note that _most_ us use more like a 30
degree bank (g load hardly noticeable after a few flights), and can go
up just fine!

And for _most_ of us, wearing a parachute doesn't have anything to do
with circling in thermals. They aren't required except in contests, but
most private owners end up with one for various reasons, and wear it
all the time (sort of like wearing a seat belt in a car). Clubs aren't
so likely to use them while flying their gliders.

Don't know about the states but we use parachutes in everything. As far
as I know everybody does in the UK.

Robin
--
Robin Birch