[NSRCA-discussion] Weather Vane or Crab

[Ron Lockhart]

Hi Ken,

I think my original phrasing is correct, but let me try restating in
different words and using
some specific examples-   This concept would be sooo much easier to describe
and understand
with the white board and beer, which I agree is looking better all the time
<VBG>)

Case 1.   No Wind.
Pilot desires airplane to go to a point that is directly north, or 360
degrees from present position.
There is no wind.
Durring flight airplane the pilot should fly the airplane on heading 360
degrees.  Track will be 360 degrees.
Airplane will get to desired point.

Case 2.   There is wind from west across desired direction of flight-  Pilot
MISSES destination.
Pilot desires airplane to go a point that is directly north, or 360 degrees
from present position.
There is wind from 270 degrees (from left of airplanes intended track)
If pilot flys airplane on heading 360 degrees, it will not get to desired
point, it will get to a point to right (or east)
of the intended point.  During flight airplane heading (direction it is
pointed) will be 360 degrees.  Track will not
be 360, it will be something to the right, such as 010 degrees.  No weather
vane is present.  The 010 track
is caused not by a weathervane effect, but by the body of air moving from
west to east while airplane progresses
through it on north heading.

Case 3   Wind direction still across desired direction of flight- Pilot FLYS
A CRAB ANGLE, and hits destination.
Stubborn pilot still wants to go to a point directly north of present
position, despite wind from 270 degrees (west).
Durring flight airplane the pilot should choose to fly the airplane on
heading 360 degrees, MINUS some number
of degrees.  Lets say pilot guesses 10 degree correction, so pilot flys
airplane on heading 350 degrees.
This is a pilot choice to fly heading 350.  The body of air moving from west
to east will not do it for the pilot.
During flight heading will be 350 degrees.  Track will be 360 degrees
(ASSUMING that the pilots
"Guess" of a 10 degree correction was right.)  Airplane will get to desired
point.  During this flight, (and in
Case 1 and 2) a yaw string would be straight, no wind hits side of airplane.

I'll have a Coors lite.

Later, Ron

----- Original Message ----- 
From: "Ken Thompson" <mrandmrst at comcast.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Saturday, October 13, 2007 9:37 AM
Subject: Re: [NSRCA-discussion] Weather Vane or Crab


> Hey Ron,
>
> Would I be correct in assuming your quote in parenthesis should read,
> "During that flight, airplane "intended" heading and track will not be the
> same", or are you pointing out that a plane will "somewhat" crab, on it's
> own, in a crosswind?
>
> BTW:  I like the white board and beer idea;-)
>
> Ken
>
> ----- Original Message ----- 
> From: "Ron Lockhart" <ronlock at comcast.net>
> To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> Sent: Saturday, October 13, 2007 8:16 AM
> Subject: Re: [NSRCA-discussion] Weather Vane or Crab
>
>
> >
> > If a pilot is flying to a specific point and points a trimmed airplane
> > directly at that point, and there is wind
> > somwhat perpendicular to the intended flight track over the ground the
> > airplane will not get to that point.
> > The airplane will get to a point down wind of the intended point.
(During
> > that flight, airplane heading and
> > track will not be the same.  There will be no wind hitting side of
plane.
> > A
> > yaw string on nose will be
> > straight down fuse)     I suppose we just lost a few folks here....
> > (sigh)
>
> All this would be a bunch easier with a white board and beer.  <VBG>
> >
> > Later,  Ron Lockhart
> >
> >
> > ----- Original Message ----- 
> > From: "Ken Thompson" <mrandmrst at comcast.net>
> > To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
> > Sent: Saturday, October 13, 2007 12:48 AM
> > Subject: Re: [NSRCA-discussion] Weather Vane
> >
> >
> >> Jim and all,
> >>
> >> Most of us realize the plane will do as you and others have described,
my
> >> only point in questioning this is...is it called "weathervaning" while
> > it's
> >> in the air, or is it called "wind induced yaw or crab"?
> >>
> >> Best to you in your recovery.
> >>
> >> Ken
> >>
> >> ----- Original Message ----- 
> >> From: "James Oddino" <joddino at socal.rr.com>
> >> To: <alberji at charter.net>; "NSRCA Mailing List"
> >> <nsrca-discussion at lists.nsrca.org>
> >> Sent: Friday, October 12, 2007 7:14 PM
> >> Subject: Re: [NSRCA-discussion] Weather Vane
> >>
> >>
> >>   If it does, this is my
> >> > definition of weathervaning.
> >> >
> >> > I'm recovering from an emergency appendectomy so I'm depending on all
> >> > you other guys to go try a cross wind stall turn with no rudder
> >> > command tomorrow and report on your results.
> >> >
> >> > Best Regards, Jim O
> >>
> >>
> >>
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> >>
> >
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