Weird Windshear

Felt like a sink, but I've never heard that term, only windshear.

"Bravo8500" wrote in message
oups.com...
Felt like a sink, but I've never heard that term, only windshear.

We use it mostly in gliders -- sometimes referred to as a downdraft
by power pilots. Glider guiders call updrafts "lift." Typically measured on
a vario(meter) in fps or knots. The only difference between a vario and an
VSI is the vario usually beeps. The pitch and period of the beeps sort of
indicate the velocity. Lift and sink work together -- somewhere in the
vicinity there was a rising volume of air. You were unlucky enough to fly
into the negative half.
Sorry if that seems patronizing or pedantic.
That brings up an autopilot question you might answer for me. If you
had not disconnected the autopilot, could it have taken you into a stall?

Downdraft, shear, microburst - bad! The ap I use (kfc200) only knows to
hold altitude, it doesn't care about airspeed, so it will gladly stall
it for you.

I say that, but in reality it may just apply so much back pressure, or
trim, and then it would simply fail to hold altitude. I've never tested
it.

On Fri, 04 Mar 2005 01:53:44 GMT, "Casey Wilson" N2310D @ gmail.com
wrote:


"Bravo8500" wrote in message
roups.com...
Felt like a sink, but I've never heard that term, only windshear.

We use it mostly in gliders -- sometimes referred to as a downdraft
by power pilots. Glider guiders call updrafts "lift." Typically measured on
a vario(meter) in fps or knots. The only difference between a vario and an
VSI is the vario usually beeps. The pitch and period of the beeps sort of
indicate the velocity. Lift and sink work together -- somewhere in the
vicinity there was a rising volume of air. You were unlucky enough to fly
into the negative half.
Sorry if that seems patronizing or pedantic.
That brings up an autopilot question you might answer for me. If you
had not disconnected the autopilot, could it have taken you into a stall?

That depends on the AP, but mine (IF set to altitude hold) will just
keep pulling the nose up until it quits flying. That means you need
to know your power settings when doing a step down approach,.Altitude
hold off, power back (by the numbers), gear down (depends), flaps
(maybe), lead the altitude with power, with the power back to the
proper setting for the approach, turn the altutude hold back on.

BTW, the FAA defines wind shear as *any* abrupt change in wind
direction or speed. That includes up and down.

Roger Halstead (K8RI & ARRL life member)
(N833R, S# CD-2 Worlds oldest Debonair)
www.rogerhalstead.com