Microbursts

Point this out to those who de-ride (pun intended)
the High Parasitic Drag Approach.


At 15:00 03 August 2006, 5z wrote:

wrote:
The 'localisation' is the problem.
To move a small volume with respect to its surroundings,
you have to
apply energy to this 'localisated package' and not
to its surroundings.
I guess lightning/thunder does that ?
Perhaps a laser could too.

Don't have time to get into details, but the best example
of
microbursts here in Colorado, is the 'virga bomb' as
often mentioned in
a forecast discussion.

The air is dry, there's a thunderstorm with cloudbase
at 18K or so. It
starts raining, so there is a localized parcel of air
containing
raindrops. As the rain falls, it evaporates due to
the dry air below.
The evaporation pulls heat from the nearby air and
it rapidly chills.
This cool air is now much heavier and begins to fall
faster, etc, etc.

I've been in situations where the air is falling so
fast, that in a 45
or more degree nose down attitude, my airspeed is still
decreasing (in
an ASW-20B). Luckily, the few times I've encountered
this, I was in or
near the landing pattern, and I flew out the side before
reaching the
ground. Others have not been so lucky, and end up
'landing' in
whatever is nearly directly below them.

-Tom