[NSRCA-discussion] Weather Vane or Crab

[Ron Lockhart]

I'll try "crab" discussion and application.

If a pilot is flying to a specific point and points a trimmed airplane
directly at that point, and there is no wind,
the airplane should get to that point.   (Durring that flight, airplane
heading and track are the same.
There will be no wind hitting side of plane.  A yaw string on nose will be
straight down fuse)

I suspect were all in agreement so far....

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)

The pilot could chose to fly a heading that is not directly pointed at the
intended point.  The pilot could
choose a heading a few degrees toward (into) the wind.  If the number of
degrees is chosen (or calculated
on the basis of accurate airplane airspeed and wind speed) correctly the
airplane will get to the 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)

The difference between the no wind heading to the point, and the heading
chosen by the pilot to compensate
for the wind is called crab angle.   The crab angle has compested for the
movement of the body of air the
airplane is flying in, while it flew toward a specific point.  The crab
angle concept applies to full scale flight in
everyday navigation to destination, and also applies to getting from over
the right pole, to over the left pole
in a cross wind.

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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