Turbulence and airspeed

On 2006-02-09, Jay Honeck wrote:
That makes a LOT more sense to me than the commonly labeled "UPdraft", which
implies a wind from below. True UPdrafts only make sense to me near the
ground, where wind over ground obstacles can create eddies and currents,
much like water in a stream burbles around rocks and other obstructions.

Not anywhere near correct, I'm afraid, as any glider pilot can tell you.
Thermals also qualify as 'updrafts', and I've spent many hours being
kept aloft by these updrafts. Even with our weak lift here, I've got my
glider to 5,300 feet on these, and in Texas I've been at over 8,000 feet
AGL. Some soaring sites get thermal lift up to 12000' AGL. Wave lift
(which can be considered an updraft, as there is a vertical component to
the air) can reach well into airliner altitudes. Gliders at Minden
regularly reach FL300 and higher.

The only part of turbulence I truly DON'T understand is the kind that tips
one wing up violently. How the heck a "parcel" of air can be so different
in the span of just 30 feet (our approximate wingspan) escapes me, but I've
had turbulence push one wing up so hard that it took nearly full opposite
aileron to remain level.

Again, try some gliding in the summer to understand this better. Quite
often in a glider, you feel one wing rising faster than the other - you
bank into this rising wing because this is where the strongest lift is.
Small, strong thermals can have a very marked boundary and it's quite
easy to have half the plane inside the thermal and half of it outside.

--
Dylan Smith, Port St Mary, Isle of Man
Flying: http://www.dylansmith.net
Oolite-Linux: an Elite tribute: http://oolite-linux.berlios.de
Frontier Elite Universe: http://www.alioth.net

That makes a LOT more sense to me than the commonly labeled "UPdraft",
which
implies a wind from below. True UPdrafts only make sense to me near the
ground, where wind over ground obstacles can create eddies and currents,
much like water in a stream burbles around rocks and other obstructions.

Not anywhere near correct, I'm afraid, as any glider pilot can tell you.
Thermals also qualify as 'updrafts', and I've spent many hours being
kept aloft by these updrafts.

Understood, but I'm making a distinction between "lift" (which is a
consistent area of "updraft") and "turbulence" (which is an inconsistent
area of "updraft" or varying relative wind, i.e.: wind shear).

The line is fine, admittedly, but the sky is complex enough to require it.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"

I'll give you one piece of advice that I have learned by experience. I
fly out of Boulder, CO. West of Boulder is the Continental Divide
rising to 14000+. The prevailing west winds come over the ridge and on
the east side of the ride there is unseen pockets of 'rotor' type
turbulence. Going west you are climbing and are slow, so if you hit
them it's not too bad. But coming east, you are descending. Pilots need
to keep their speed down here. It is easy to point the nose down and
gain speed. Sometimes, except for these turbulence pockets, the route
is smooth, so that doubles the temptation to come down fast. When you
hit the pocket of turbulence it is usually just one or two "thwaps",
like giant hit the top of the wings with a big flyswatter. Then smooth
again. This is one place where keeping an eye on Va is essential.