"Chris Reed" wrote in message
...
Jmarc99 wrote:
You wrote that something like 90 degrees= nil wind. So if someone
do a slip in the wind direction in order to sayt alligned with the runway
during the final leg, the pitch angle of the sailplane is somewhere
greater
than supposed! In this case, with 90 degree wind, the sailplaine have
to travel a longer way through the air mass.

Though, the sailplane fly more faster than supposed, and the pilot
doesn't use much airbrake! Is that what effectively happen in that
wind condition?

Jmarc


I'm not suer I understand the question properly.

My crosswind landing technique is to crab into wind, and then kick off the
drift after the roundout. This works fine for, say, a 10kt crosswind at 90
degrees, and at that wind speed there's no real danger of wind shear.

I also prefer crabing than slipping!
I also agree that a little wind, coming from any direction, can't produce
dangerous wind shear. No wind means no real effective change in the
wind speed or wind direction.


However, if the wind is gusting 20kts or more at 90 degrees, that's
outside the demonstrated crosswind limits of my glider. Ideally, I choose
a better landing direction. If I had no choice (e.g. poor or late field
selection), then this would be one of those "interesting" landings which
test one's improvisational and piloting skills. I'd be using a combination
of crabbing and slipping, to give me less drift to kick off,and I'd
certainly add 10 kts or more to allow for gusts and wind shear unless that
seemed more dangerous than approaching at a slower speed.

I guess the point I was really trying to make is that if on every landing
you add extra speed for "safety", the result is that you never learn to
land with the minimum safe energy.

No need for extra speed when there is no wind at all! I agree again
that is important to learn to land with the minimum safe energy..!

This is a skill that I think every XC pilot needs. However, in gusty or
high winds, you have to allow for the possibility of needing extra control
authority or suddenly losing 15kts airspeed through wind shear. So minimum
safe energy landings are for benign conditions.

The real point to talk in this thread is "how much" speed to add to
the 1.3 Vstall speed, depending on the wind speed? Especially if
the wind come from a side or the back!

All pilots seams to say that only the heading portion of the wind
should be took in care, when choosing the landing (circuit) speed.

Is someone might agree that a 15-20 knots wind, at low altitude
(like the final leg) may produce windshear that may lower the
the relative airspeed, instead of increasing it, even when the
wind come frome the back?

This is the real question. I think that very experienced glider
pilots, lurkink in this newsgroup, might have someting very
interesting to say about that!

Sure, the good thing is to land upwind, anyway! But, is that
right to reduce the speed to only 1.3 Vstall when you realize,
when doing the base leg, you're going to land tailwind?

Thanks Chris, for your interest to this question!

Jmarc...