David Megginson [EMAIL PROTECTED] said:
No, that's not right after all. Following a message from Jon Berndt,
I took a peek at the property browser, and the wind-{north|east}-fps
is the to- direction, not the from- direction. JSBSim was using the
from- direction already, while the other
RADIS, do you?
=Martin=http://www.iradis.org/
PGP: FE87448B DDF8 677C 9244 D119 4FE0 AE3A 37CF 3458 FE87 448B
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind confusion.
In-Reply-To: [EMAIL PROTECTED]; from [EMAIL PROTECTED] on Mon
. :-)
- --
Regards, I RADIS, do you?
=Martin=http://www.iradis.org/
PGP: FE87448B DDF8 677C 9244 D119 4FE0 AE3A 37CF 3458 FE87 448B
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind confusion.
In-Reply-To: 005501c1b800$8c154700$[EMAIL
From: Andy Ross [EMAIL PROTECTED]
That is a to vector, by definition. Really, the
from convention applies to a 1-dimensional compass direction; I'm
not aware of anyone else trying to apply it to a 3D vector environment.
Ooh! Yeah, that is a good point about the 3D part of it. It's been a
From: Martin van Beilen [EMAIL PROTECTED]
In the same vein, it is a convention to report vertical winds as
'to' headings. Although vertical heading is binary, it is
reported as 'to-up', not 'from-down'. So if you want to stick to
the meteo conventions, your horizontal components should be
Jon S. Berndt [EMAIL PROTECTED] said:
Was there a properties way to do it that is opposite to the above? Perhaps
we are given too much power! ;-)
In the /environment path there are variables for wind direction that specify a
force value as fps from east and/or north, the sum of which
representations of wind should be *to*. (imho).
- --
Regards, I RADIS, do you?
=Martin=http://www.iradis.org/
PGP: FE87448B DDF8 677C 9244 D119 4FE0 AE3A 37CF 3458 FE87 448B
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind
David Megginson writes:
And guess what I discovered when diffing 0.7.8 against 0.7.9? In
Main/options.cxx, around line 900, someone *commented out* the
line dir += 180;, thereby *changing* the definitions of
/environment/wind-{north,east}-fps! Okay, who did that? Just wait
fgfs --aircraft=c172 --airport-id=KSFO --heading=270 --wind=0@50
The JSBSim C172 actually takes off, weathervanes in the air, then
lands again facing north. The LaRCSim C172 flips over, and the UIUC
C172 starts sliding smoothly sideways. YASim takes the prize for this
one, since it
[EMAIL PROTECTED] writes:
Is this now how the system works?
The command-line option has always been meant (and documented) to give
the from direction. I guess it's still up for grabs how the internal
NED properties represent wind.
All the best,
David
--
David Megginson
[EMAIL
Alex Perry writes:
fgfs --aircraft=c172 --airport-id=KSFO --heading=270 --wind=0@50
The JSBSim C172 actually takes off, weathervanes in the air, then
lands again facing north. The LaRCSim C172 flips over, and the
UIUC C172 starts sliding smoothly sideways. YASim takes the
prize
David Megginson writes:
No, that's not right after all. Following a message from Jon Berndt,
I took a peek at the property browser, and the wind-{north|east}-fps
is the to- direction, not the from- direction. JSBSim was using the
from- direction already, while the other FDM's were usign
Alex Perry writes:
I suspect the LaRCSim is the most accurate. It is possible to taxi
(carefully) with those winds, but takes considerable planning and
operation of the controls to make it work out safely.
David comments:
The tests were run with the plane stationary, engine at idle,
Alex Perry writes:
For a slight headwind, or a slight tailwind, you can use the
ailerons to modify the effective angle of attack and oppose that
rolling torque. However, the stated example is exactly at 90
degrees and thus this would have no effect. In real life, you'd
zigzag down
BTW, it's good to see that people have started experimenting with
various combinations of wind and FDM's. There are interesting
differences in ground handling between various models.
Speaking of ground handling, all aircraft have the tendency to
slowly float sideways, even with zero wind,
you?
=Martin=http://www.iradis.org/
PGP: FE87448B DDF8 677C 9244 D119 4FE0 AE3A 37CF 3458 FE87 448B
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind confusion.
In-Reply-To: [EMAIL PROTECTED]; from [EMAIL PROTECTED] on
Mon, Feb 18
?
=Martin=http://www.iradis.org/
PGP: FE87448B DDF8 677C 9244 D119 4FE0 AE3A 37CF 3458 FE87 448B
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind confusion.
In-Reply-To: [EMAIL PROTECTED]; from [EMAIL PROTECTED] on
Sat, Feb 16, 2002 at 04
Tony Peden [EMAIL PROTECTED] said:
I'd be happier if we kept it as is. Wouldn't be the first time
engineers have traded correctness for pragmatism.
Ah pragmatism! Is that the excuse engineers use when they get their vectors
math bass-ackwards? ;-)
Best,
Jim
On Sun, Feb 17, 2002 at 04:00:03PM -, Jim Wilson wrote:
Tony Peden [EMAIL PROTECTED] said:
I'd be happier if we kept it as is. Wouldn't be the first time
engineers have traded correctness for pragmatism.
Ah pragmatism! Is that the excuse engineers use when they get their vectors
Bah humbug. Engineers, seeing that there were two incompatable
standards simply choose to break the one normally seen by people who
should be able to understand the problem and adapt. Obviously, in this
case, they chose the wrong group. :)
Ha! Someone made the suggestion that we are doing
Martin van Beilen wrote:
I think I am beginning to understand what the source of the
confusion is. As most of you know, weather reports specify the winds
as a _from_ heading. However, in simulated space I tend to think of
wind as a vector, i.e. a _to_ heading. Apparently, two out of three
Martin van Beilen [EMAIL PROTECTED] said:
I have been playing around with the wind some more, and it seems
that JSBSim doesn't only have the up/down winds inverted, but the
north and east winds as well.
Hmmm...doesn't look like it to me. Just rolling down the runway I applied a
200knot
From: Martin van Beilen [EMAIL PROTECTED]
To: [EMAIL PROTECTED]
Subject: Re: [Flightgear-devel] Wind confusion.
In-Reply-To: [EMAIL PROTECTED]; from [EMAIL PROTECTED] on Sat,
Feb 16, 2002 at 09:57:25PM -
X-S-Issue: [EMAIL PROTECTED] 2002/02/16 23:31:56
24b4ecf6e536a36cee51907741fe94b6
Please note that there is a difference between fgfs's internal
representation of wind, and the way it is set by the user. As an
engineer, I am partial to using 'to' vectors internally.
Yup, that is more mathematically correct.
IMHO, I think the way JSBSim does it is more consistent from
On Sat, 2002-02-16 at 15:22, Jon S. Berndt wrote:
Please note that there is a difference between fgfs's internal
representation of wind, and the way it is set by the user. As an
engineer, I am partial to using 'to' vectors internally.
Yup, that is more mathematically correct.
Please note that there is a difference between fgfs's internal
representation of wind, and the way it is set by the user. As an
engineer, I am partial to using 'to' vectors internally.
Yup, that is more mathematically correct.
There is nothing mathematical about the wind vector
Tony Peden writes:
One could apply a similar argument to a vane; it doesn't change the
fact that the air is flowing the other way ( and that may well be
why the aviation convention is from )
And here in the northern hemisphere when you refer to a 'north wind'
you are usually talking about
On Sat, 2002-02-16 at 16:56, Curtis L. Olson wrote:
Tony Peden writes:
One could apply a similar argument to a vane; it doesn't change the
fact that the air is flowing the other way ( and that may well be
why the aviation convention is from )
And here in the northern hemisphere when
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