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