AviationBanter - View Single Post

5Z

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