[NSRCA-discussion] Weather Vane or Crab

[george w. kennie]

Welllll,.......except for a few mountains...................


----- Original Message ----- 
From: "James Oddino" <joddino at socal.rr.com>
To: "NSRCA Mailing List" <nsrca-discussion at lists.nsrca.org>
Sent: Sunday, October 14, 2007 8:50 PM
Subject: Re: [NSRCA-discussion] Weather Vane or Crab


> 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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