NavList:

   

Reply

When teaching student pilots to navigate you start them out drawing a
vector diagram of the "wind triangle" to calculate wind correction
angle and ground speed to make sure they understand what is going on.
After that you introduce them to the E6-B which is just a convenient
way to draw the same vector diagram. Here is a picture of an E6-B:

http://www.rekeninstrumenten.nl/pages%20and%20pictures/12081.jpg

The right hand image shows the "wind side" of the computer but,
unfortunately, it show the slide inserted upside down in an unusable
orientation.

I prefer the MB-2A which doesn't require a pencil and doesn't require
drawing the vector diagram but for many pilots the E6-B is probably a
better choice since it draws a visual picture of what is going on so
as to avoid confusion.

The MB-2A solves the same problem with trig using the rule of sines.
http://www.rekeninstrumenten.nl/pages%20and%20pictures/12071.jpg



The Russian flight computers work the same way an you can buy on on
ebay:


http://search.ebay.com/navigation-slide-rule_W0QQcatrefZC6QQdfspZ32QQfromZR9QQfromZR9QQfstypeZ1QQftrtZ1QQftrvZ1QQsabfmtsZ1QQsacatZQ2d1QQsaobfmtsZinsifQQsspagenameZSTRKQ3aMEFSRCHQ3aSRCH

I liked to play with  my students by giving them a problem to solve an
then hand them my Russian flight slide rule to use, I liked to see
that "deer look in the headlights look" on their faces.

The circular flight computers have an advantage over the newer digital
flight computers in that once you have them set to your ground speed
you can lay them down and then pick them up later and just glance at
them to solve further problems, no need to turn them on again and
reenter data a second time.

gl



On Aug 2, 10:12�am, Paul Hirose  wrote:
> 01 0609
>
> Renee Mattie wrote:
> > I saw an old Weems and Plath Dalton E6B at Bacon's and snapped it up.
> > Imagine my surprise to see that they are still making these things,
> > and offering them for sale athttp://www.mypilotstore.com/MyPilotStore/secp/22.
>
> > On the slide-rule side, the grommet seems to be off-center. �So if I
> > set the dial for 60 miles/hour, I'll apparantly go almost 18.1 miles
> > in 18 minutes, though almost exactly 9 miles in 9 minutes.
>
> > Have I got a good one or a bad one?
>
> A not so good one, I guess. The centering error on mine is barely
> detectable, about the width of a line.
>
> I also have a Jeppesen CR-2 flight computer. It's much more compact than
> an E-6B because the effect of wind is calculated by a different
> principle. With the side of the device that's pictured at the web site,
> you separate wind into headwind and crosswind components. Crosswind and
> true airspeed are set on a sine scale (around the outside in the
> picture) to obtain wind correction angle. Headwind is mentally
> subtracted from true airspeed to obtain groundspeed.
>
> By contrast, on an E-6B you construct the wind triangle and read
> wind correction angle and groundspeed directly. The solution takes
> more space, but workload is less.
>
> Either computer can solve for drift and set in marine navigation. Just
> mentally apply a convenient scaling factor of 10, 20, etc. to the values
> on the wind and airspeed scales. I solved some of the old Silicon Sea
> problems that way.
>
> For time / speed / distance computations both devices have the same
> facilities. As usual with slide rules, the user is responsible for
> placing the decimal point, so ship speeds are as easy to handle as
> airplane speeds. Or car speeds -- I used my E-6B a few days ago to check
> speedometer error.
>
> When compressibility is significant (say, above .4 Mach) the CR
> computers are superior at converting calibrated airspeed to true
> airspeed. E-6Bs assume incompressible flow, so they're inaccurate at jet
> cruise speeds. But airspeed computation is simpler, and the error means
> nothing at typical light plane speeds.
>
> Deluxe E-6Bs are made of sheet aluminum, while CRs are plastic and can
> warp if left in a hot car.
>
> --
> I block messages that contain attachments or HTML.
--~--~---------~--~----~------------~-------~--~----~
Navigation List archive: www.navlist.net
To post, email NavList@navlist.net
To , email NavList-@navlist.net
-~----------~----~----~----~------~----~------~--~---

   

Reply