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    Re: Regarding fix bearings
    From: Gary LaPook
    Date: 2008 Dec 26, 01:55 -0800

    Sure Mike we can do that. I fly out of SZP, I live in Moorpark. I
    haven't heard from Greg, he lives in Simi Valley. Where are you
    located?
    Perhaps the three of us could get together and shoot some sun lines in
    flight, you will find it quite different than marine practice.
    
    gl
    
    On Dec 21, 5:57�pm, m_bur...@MSN.COM wrote:
    > Hey GL, Mike Burkes here I would love to! I had a 1962 C-172 �based at
    > El Monte(EMT). I have a Private Pilot with Instrument Rating and 1000+
    > hrs total time but am not current. �Did your C-172 have an astrodome?
    > Just make sure a B-747 does not appear in your bubble or it will burst
    > more than your bubble ha! But seriously that sounds like super great
    > stuff!
    > Mike Burkes
    >
    > On Dec 21, 2:34�pm, "Gary J. LaPook"  wrote:
    >
    > > Not just the military teaches this technique Greg. I have attached an
    > > illustration from the 1998 edition of the Jeppesen Instrument Commercial
    > > Manual which shows the same thing. Note that this page also illustrates
    > > the "double the angle on the bow" technique which works real well in
    > > aircraft. I have been a CFI, airplane, instrument and multiengine since
    > > 1972 and have taught this method.
    >
    > > I fly out of Santa Paula and CMA and I used to flight instruct at Navy
    > > Point Mugu. Are you still flying? About a month ago I had to fly on
    > > business down to Corona from SZP. I rented a Cessna 172 with an
    > > autopilot and shot two sunlines on the way with my MA-2. When checked
    > > against the GPS one line was off by three NM and the other by five NM.
    > > Want to go flying sometime and shoot some sunlines?
    >
    > > gl
    >
    > > Greg R. wrote:
    > > > --- On Sun, 12/21/08, Gary J. LaPook  wrote:
    >
    > > >> Another method is taught to every instrument rated pilot.
    > > >> With the station near the wing tip (near the beam if talking about
    > > >> ships) measure the time it takes for a certain number of degrees of
    > > >> bearing change in seconds. Then divide the seconds by the number of
    > > >> degrees of bearing change and the result is the distance to the station
    > > >> in minutes.
    >
    > > > Seems like I remember reading about that method in my instrument ground 
    school books way back when (mid-70s), but I can't recall ever using it in 
    practice (we mostly used DME back then, and GPS these days). I think you got 
    some/most/all of your flight training in the military (?), so that curriculum 
    might have been different from what us civilians were taught.
    >
    > > > Of course, alternate methods of navigation are always good to have in 
    your back pocket, and I wouldn't sell it short by any means.
    >
    > > > --
    > > > GregR
    >
    > > > --- On Sun, 12/21/08, Gary J. LaPook  wrote:
    >
    > > >> From: Gary J. LaPook 
    > > >> Subject: [NavList 6784] Re: Regarding fix bearings
    > > >> To: NavList@fer3.com, "Beverley Maxwell" 
    > > >> Date: Sunday, December 21, 2008, 1:59 AM
    > > >> It looks like the classic "double the angle on the
    > > >> bow" technique. I am
    > > >> attaching Dutton's explanation.
    >
    > > >> Another method is taught to every instrument rated pilot.
    > > >> With the
    > > >> station near the wing tip (near the beam if talking about
    > > >> ships) measure
    > > >> the time it takes for a certain number of degrees of
    > > >> bearing change in
    > > >> seconds. Then divide the seconds by the number of degrees
    > > >> of bearing
    > > >> change and the result is the distance to the station in
    > > >> minutes. This
    > > >> works because the tangent of �one degree is approximately
    > > >> equal to 1/60
    > > >> and this approximation holds true for small angles.
    > > >> The actual formula is (time/degrees of bearing change) x 60
    > > >> = time to
    > > >> the station. By measuring the time in seconds the
    > > >> multiplication by 60
    > > >> is accomplished automatically when you take the result in
    > > >> minutes. The
    > > >> formula can also be worked to find distance. Simply measure
    > > >> the time in
    > > >> minutes and multiply by your speed in knot, then divide by
    > > >> the number of
    > > >> degrees of bearing change to give you your distance off in
    > > >> nautical
    > > >> miles. Measuring in minutes and multiplying by your speed
    > > >> takes care of
    > > >> the internal multiplying �by 60. In flying the bearings are
    > > >> measured
    > > >> with and ADF or VOR but the same technique works with
    > > >> visual bearings.
    >
    > > >> A simple example. Say it takes 120 seconds for the bearing
    > > >> to change 10
    > > >> degrees. 120/10 = 12 minutes to the station. The same
    > > >> example, 120 knots
    > > >> times 2 minutes divided by 10 puts you 24 NM from the
    > > >> station. This is
    > > >> the same result as multiplying the 120 knot speed by 12
    > > >> minutes divided
    > > >> by 60 minutes per hour. I have attached an excerpt from FM
    > > >> 1-240 that
    > > >> illustrates this.
    >
    > > >> gl
    >
    > > >> George Huxtable wrote:
    >
    > > >>> in...@yahoo.com, or A-08, wrote the posting copied
    >
    > > >> below.
    >
    > > >>> That idea sounds original, simple, and interesting.
    >
    > > >>> Tell us more, A-08.
    >
    > > >>> George.
    >
    > > >>> contact George Huxtable, at �geo...@hux.me.uk
    > > >>> or at +44 1865 820222 (from UK, 01865 820222)
    > > >>> or at 1 Sandy Lane, Southmoor, Abingdon, Oxon OX13
    >
    > > >> 5HX, UK.
    >
    > > >>> ----- Original Message -----
    > > >>> From: 
    > > >>> To: 
    > > >>> Sent: Saturday, December 20, 2008 2:12 AM
    > > >>> Subject: [NavList 6773] Regarding fix bearings
    >
    > > >>> |
    > > >>> | Regarding fix bearings: A convenient practice of
    >
    > > >> taking two bearings at
    >
    > > >>> one landmark is to take the first bearing at 45 deg,
    >
    > > >> then second bearing is
    >
    > > >>> taken off beam (90 deg). �In this case distance off
    >
    > > >> beam is equal distance
    >
    > > >>> traveled.
    > > >>> | There are also few so-called "magic"
    >
    > > >> angles which play the same trick:
    >
    > > >>> upon using them distance travelled is equal distance
    >
    > > >> off.
    >
    > > >>> |
    > > >>> | I wrote a formula which permits for the first
    >
    > > >> bearing chose any angle you
    >
    > > >>> want and then calculate the angle for the second
    >
    > > >> bearing which, as a result,
    >
    > > >>> equals distance travelled to distance off.
    > > >>> |
    > > >>> | I think it gives some flexibility in bearing taking
    >
    > > >> and especially in
    >
    > > >>> calculating distance off.
    > > >>> |
    > > >>> | Respectfully,
    > > >>> |
    > > >>> | A-08
    > > >>> |
    > > >>> |
    > > >>> | ------------------------------------------
    > > >>> | [Sent from archive by: inuik-AT-yahoo.com]
    >
    > > �jepp2-66.jpg
    > > 558KViewDownload- Hide quoted text -
    >
    > > - Show quoted text -
    >
    >
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