[NSRCA-discussion] Weather Vane or Crab

Mon Oct 15 13:01:43 AKDT 2007

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
> >>>>>
> >>>>>
> >>>>>
> >>>>> _______________________________________________
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> >>>>> http://lists.nsrca.org/mailman/listinfo/nsrca-discussion
> >>>>>
> >>>>
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