I think this would apply to what would feel like an updraft. The
second most important thing that an airplane does is provide lift when
you give it airspeed. A sudden supply of airspeed would give a sudden
burst of lift, and feel like an updraft. In fact, I think that would
be a lot more efficient way to lift an airplane than blowing air up
from underneath it at any speed.

Interesting. So what we've always interpreted as an "updraft" is *really*
an increase in relative wind, which (in turn) increases (or decreases) lift?

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.

A change in relative wind would also better explain the other common type of
turbulence, where the tail is "kicked" to one side or another, creating that
annoying "fishtail" feeling.

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.
--
Jay Honeck
Iowa City, IA
Pathfinder N56993
www.AlexisParkInn.com
"Your Aviation Destination"