[NSRCA-discussion] Weather Vane or Crab

Nat Penton natpenton at centurytel.net
Mon Oct 15 13:46:37 AKDT 2007


Or involuntary reflexes                            Nat
  ----- Original Message ----- 
  From: Bob Richards 
  To: NSRCA Mailing List 
  Sent: Monday, October 15, 2007 4:01 PM
  Subject: Re: [NSRCA-discussion] Weather Vane or Crab


  Funny, I don't think anyone has mentioned coriolis effect yet. :-)

  Bob R.


  Ron Lockhart <ronlock at comcast.net> wrote:
    Assuming earth is flat - well of course! Same as aircraft carrier. 
    And in this case agreeing with Georgie, expect for a few mountains.

    Later, Ron

    ----- Original Message ----- 
    From: "george w. kennie" 
    To: "NSRCA Mailing List" 
    Sent: Monday, October 15, 2007 9:46 AM
    Subject: Re: [NSRCA-discussion] Weather Vane or Crab


    > 
    > Welllll,.......except for a few mountains...................
    > 
    > 
    > ----- Original Message ----- 
    > From: "James Oddino" 
    > To: "NSRCA Mailing List" 
    > 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
    > >> )
    > >>
    > >> 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" 
    > >> To: "NSRCA Mailing List" 
    > >> 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" 
    > >>> To: "NSRCA Mailing List" 
    > >>> 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. 
    > >>>>
    > >>>> Later, Ron Lockhart
    > >>>>
    > >>>>
    > >>>> ----- Original Message -----
    > >>>> From: "Ken Thompson" 
    > >>>> To: "NSRCA Mailing List" 
    > >>>> 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" 
    > >>>>> To: ; "NSRCA Mailing List"
    > >>>>> 
    > >>>>> 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
    > >>>>>
    > >>>>>
    > >>>>>
    > >>>>> _______________________________________________
    > >>>>> NSRCA-discussion mailing list
    > >>>>> NSRCA-discussion at lists.nsrca.org
    > >>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
    > >>>>>
    > >>>>
    > >>>> _______________________________________________
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    > >>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
    > >>>
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    > >>
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