Wind information

On 10/3/2010 11:09 AM, Brad wrote:
On Oct 3, 10:44 am, wrote:

Brad, I thought your come back was funny and I certainly deserve it.

What I get from your opening thread is perhaps your reluctance to
trust the wind information you are seeing or you are looking for
supporting information that would increase your trust in the
information.
Transitioning to ridge would require accurate wind information, but
you write you do this without fear all the time.
If you would elaborate a little more on what you are thinking
regarding wind data , I'm sure others have helpful input and comments.
Myself , operating a 302 with a CAI M-25 backup...they become accurate
as long as I thermal and slowly diverge / degrade with long stretches
of glides. A few turns and I am amaze how quickly they recapture the
wind. I was able to run trials base on observation of smoke coming off
the burning sugarcane fields and learn my instrument.
R
I do feel confident that the wind information is reliable enough to
use within a certain amount of time/airspace. What I mean by that is
since I only get wind info from circling (with my set-up) it is good
only for a certain amount of time until I start circling again. So, If
I climb up and get wind info X, then start a long glide the wind could
be different when I finish my glide and I'll not know what it is until
I start circling again and get a new fix. Probably not a big deal when
I think about it.

It could be a big deal if you are ridge flying, or flying in the
mountains (that's' _in_ not _over_), or wave is present but not strongly
established. Under those conditions, the wind can change significantly
from where you last circled due to valley flows, mountain peaks/ridges
diverting the wind, or wave dipping down into the convection layer (or
coming and going as the speed, direction, and air mass change).

My experience is wind derived from circling is adequate for relatively
open areas, like the Columbia basin in Eastern Washington state, but
"current headwind" derived from an air-data vario like the my 302 is
very useful in the ridge/mountain/wave situations. And, of course,
during long glides (like a final glide), where the glider sinks
thousands of feet lower than the altitudes I at which I was circling and
getting wind measurements.

If wind is important to you, spend the money for an air-data instrument.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz

LK8000 has had a feature called TrueWind for some months now.
By flying at a preset speed for a preset time (say 60kts for 10 secs, but
you choose when configuring), in one of 12 directions, and pressing a
button, you will get the wind. Sounds complicated, but in practice it
isn't. Ideal for checking the wind on a long final glide. You might have
to change heading, but no more than 15 deg, for the 10 secs. However, if
your compass is not accurate, the wind won't be.
Dave

At 02:54 04 October 2010, Eric Greenwell wrote:
On 10/3/2010 11:09 AM, Brad wrote:
On Oct 3, 10:44 am, hretting wrote:

Brad, I thought your come back was funny and I certainly deserve it.

What I get from your opening thread is perhaps your reluctance to
trust the wind information you are seeing or you are looking for
supporting information that would increase your trust in the
information.
Transitioning to ridge would require accurate wind information, but
you write you do this without fear all the time.
If you would elaborate a little more on what you are thinking
regarding wind data , I'm sure others have helpful input and
comments.
Myself , operating a 302 with a CAI M-25 backup...they become
accurate
as long as I thermal and slowly diverge / degrade with long stretches
of glides. A few turns and I am amaze how quickly they recapture the
wind. I was able to run trials base on observation of smoke coming
off
the burning sugarcane fields and learn my instrument.
R
I do feel confident that the wind information is reliable enough to
use within a certain amount of time/airspace. What I mean by that is
since I only get wind info from circling (with my set-up) it is good
only for a certain amount of time until I start circling again. So, If
I climb up and get wind info X, then start a long glide the wind could
be different when I finish my glide and I'll not know what it is
until
I start circling again and get a new fix. Probably not a big deal when
I think about it.

It could be a big deal if you are ridge flying, or flying in the
mountains (that's' _in_ not _over_), or wave is present but not
strongly
established. Under those conditions, the wind can change significantly
from where you last circled due to valley flows, mountain peaks/ridges
diverting the wind, or wave dipping down into the convection layer (or
coming and going as the speed, direction, and air mass change).

My experience is wind derived from circling is adequate for relatively
open areas, like the Columbia basin in Eastern Washington state, but
"current headwind" derived from an air-data vario like the my 302 is
very useful in the ridge/mountain/wave situations. And, of course,
during long glides (like a final glide), where the glider sinks
thousands of feet lower than the altitudes I at which I was circling and

getting wind measurements.

If wind is important to you, spend the money for an air-data instrument.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to
email
me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarm
http://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of
what
you need to know tinyurl.com/yfs7tnz

On Oct 3, 10:54*pm, Eric Greenwell wrote:
On 10/3/2010 11:09 AM, Brad wrote:



On Oct 3, 10:44 am, *wrote:

Brad, I thought your come back was funny and I certainly deserve it.

What I get from your opening thread is perhaps your reluctance to
trust the wind information you are seeing or you are looking for
supporting information that would increase your trust in the
information.
Transitioning to ridge would require accurate wind information, but
you write you do this without fear all the time.
If you would elaborate a little more on what you are thinking
regarding wind data , I'm sure others have helpful input and comments.
Myself , operating a 302 with a CAI M-25 backup...they become accurate
as long as I thermal and slowly diverge / degrade with long stretches
of glides. A few turns and I am amaze how quickly they recapture the
wind. I was able to run trials base on observation of smoke coming off
the burning sugarcane fields and learn my instrument.
R
I do feel confident that the wind information is reliable enough to
use within a certain amount of time/airspace. What I mean by that is
since I only get wind info from circling (with my set-up) it is good
only for a certain amount of time until I start circling again. So, If
I climb up and get wind info X, then start a long glide the wind could
be different when I finish my glide and I'll not know what it is until
I start circling again and get a new fix. Probably not a big deal when
I think about it.

It could be a big deal if you are ridge flying, or flying in the
mountains (that's' _in_ not _over_), or wave is present but not strongly
established. Under those conditions, the wind can change significantly
from where you last circled due to valley flows, mountain peaks/ridges
diverting the wind, or wave dipping down into the convection layer (or
coming and going as the speed, direction, and air mass change).

My experience is wind derived from circling is adequate for relatively
open areas, like the Columbia basin in Eastern Washington state, but
"current headwind" derived from an air-data vario like the my 302 is
very useful in the ridge/mountain/wave situations. And, of course,
during long glides (like a final glide), where the glider sinks
thousands of feet lower than the altitudes I at which I was circling and
getting wind measurements.

If wind is important to you, spend the money for an air-data instrument.

--
Eric Greenwell - Washington State, USA (change ".netto" to ".us" to email me)
- "Transponders in Sailplanes - Feb/2010" also ADS-B, PCAS, Flarmhttp://tinyurl.com/yb3xywl
- "A Guide to Self-launching Sailplane Operation Mar/2004" Much of what you need to know tinyurl.com/yfs7tnz- Hide quoted text -

- Show quoted text -

I agree with Eric.
Circling winds are useful for general information and adequate for
much of our flying but they fall short in 2 very important aspects.
1. Long glides through deep boundary layers with direction changes in
the boundary layer. Really good wind info from air data/ GPS
computation updates your situation which can make final glides more
accurate and, most useful for me, I can see direction changes to help
me picture where shears are and what direction they are.
2. I somtimes go for quite some time on the ridge without circling.
Knowing the wind vector is hugely useful, in terms of how ridge works
now and what the trend is during the day. Can I go to Cumberland 90
miles away and use this turnpoint a couple hours from now?
FWIW
UH

On Oct 3, 7:54*pm, Eric Greenwell wrote:

If wind is important to you, spend the money for an air-data instrument.

Even the best on board measuring system can only tell you what the
wind is here and now, and what it was where and when.

No on-board measuring system can tell you what the wind will be
someplace you have not been yet at some time in the future, and that
is what we need for those long final glides and presumably for long
ridge flights and ridge transitions.

Flight management systems allow the entry of wind forecasts at
multiple altitudes for the various en-route waypoints. Perhaps a smart
glider flight computer would allow entry of discrete point wind
forecast data, or even derive them automatically from a web source.
Perhaps a smarter one would enable the wind forecast data to be
updated in flight. For example local winds at different altitudes
could be derived from FLARM transmissions from other gliders in the
area.

One problem with dreaming of systems like this is that in-flight
reception of weather data, other than by voice radio, is prohibited by
US contest rules. It's OK to listen to an AWOS or ATIS but not OK to
receive the same data from, for example, XM weather.

In the past looking outside has provided very useful indicators of
wind strength and direction. I see no reason to assume that source
will go away as technology advances.

Andy

On Sun, 03 Oct 2010 19:54:52 -0700, Eric Greenwell
wrote:

If wind is important to you, spend the money for an air-data instrument.

If someone flies in mountain environment, I feel I can recommend the
Zander vario-computer, coupled to an electronic (rs232) interface on
the compass. (I have no connection with the maker nor any seller).

I have used computers of many brands, many models, I have fine tuned
almost every possible variant, but in the end I was hardly satisfied.
Nothing beats the Zander setup (if you can guess through the obscure
reasoning which inspired the author of the user's manual).

Just don't think about other setups based around solid state
compasses; the affordable ones are too pitch sensitive to be of any
use.

With the Zander, once it's correctly tuned (airspeed, and extremely
careful compass calibration), you get a consistent, reliable wind
reading. If you see sudden changes, in direction, you may be
reasonably sure the wind is locally deviated by some local features or
breeze. It happens frequently. I find it interesting and sobering
(thinking, the risks of wind-shears when ridge flying).

On occasions, such local wind regimes can have a huge influence on
your average speed on a competition task, and the information I get
from the Zander gave a few very valuable opportunities)

I have tested the "True Wind" function in LK8000 for PDA, and I was
positively impressed. Keeping accurate compass heading and speed is
easier than I thought when crossing valleys, while it's out of
question when close to approaching a ridge.
Of course, my Duo has a perfectly calibrated compass.

Aldo Cernezzi