[NSRCA-discussion] Weather Vane or Crab

[James Oddino]

Ron, you are assuming the earth is flat.  (vbg)

Jim


On Oct 13, 2007, at 9:42 AM, Ron Lockhart wrote:

> 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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