[NSRCA-discussion] Weather Vane or Crab

Matthew Frederick mjfrederick at cox.net
Sun Oct 14 16:43:45 AKDT 2007


Ron, I was halfway through almost the exact thing, but I gave up figuring 
nobody would listen anyway.

Matt
----- Original Message ----- 
From: "Ron Lockhart" <ronlock at comcast.net>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Saturday, October 13, 2007 11:42 AM
Subject: Re: [NSRCA-discussion] Weather Vane or Crab


> 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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