Wind calculations on the E6B - I think.

[flying dog]

Folks,

 

Sorry if I have been down this road before, but I am again thinking.

 

I have a KANE computer and on the back you have the "graph lines" where you do wind calcs.

 

Thing is this:

 

The instrucation say to do it a particular way.

 

To me, it is counter-intuitive.

 

Before I rant on too much, here is a link:

 

Flight Computer

 

They show you can do it ANOTHER way and get the SAME answer.

 

I can see how too. But I am not 100% sure it is "legit'" in how I am doing it/using it.

 

I prefere to use it the "other way" where I leave the centre circle stationary after setting the wind and calculate the ground speed from the tip of the wind line.

 

This saves moving the clear plastic up and down as you rotate the wheel with the changing wind/heading things.

 

I can't "talk the talk" and use the correct names and all that stuff to explain how I believe that the second way is a "mirror" of the first OFFICIAL way.

 

Can someone help me though the reasoning why I believe the way I "discovered" and that is explained/demonstrated on the link works too?

 

 

[Yenn]

Nobody else has jumped in here with an answer, probably because the question is not clear, so I will start it off. I don't have my computer here as it is in the plane, so my numbers will not be accurate, but I hope you get the idea.

 

Start by getting the wind forecast, say for example 135 deg 20 kts.

 

On the correct side for the speed you travel at, set the circular scale at 135 deg, and put the centre mark on the transparent disk over a horizontal line.

 

Draw a pencil line down a distance with an inverted arrow head at the bottom corresponding to wind speed. ie 20kts.

 

Now put the centre mark over your TAS. Say 100 kts.

 

Set the circular scale to the track you want to achieve, say for example 045 deg.

 

You will now see the arrow head has been moved to a new position.

 

Read off the drift from the radiating lines. Not having the computer handy I am guessing at it reading about 5deg to the left of the vertical line which is 45 deg.

 

This is telling you that at 45 deg heading, you will have left drift of 5 deg, giving you a track of 40 deg. To correct this, rotate the circular scale to the rightabout 3 deg. to 48 deg heading. If this now shows 3 deg of left drift, you would be tracking at 45 deg, if not just move it around to fine tune it so that drift with heading equals desired track.

 

When this is done you can read off GS from under the arrow head.

 

Hard to explain without the computer in hand, but someone else may be able to shed more light on the subject if I am not clear enough.

 

 

[flying dog]

Yenn,

 

Thanks for the reply, but honestly I think you need to look at the link.

 

I know how to use the calculator as you discribed, but the link makes it just THAT much easier to use. The only "problem" is the drift numbers are reversed. Left = right and Right = left.

 

Other people are adoment (spelling?) that there is only one way to use the device, and that is how it is explained in the manual. This is fair enough, but I am curious to why/how this other way works just as well - AND, want someone to confirm that it is actually correct.

 

 

[Yenn]

I did look at the link and that is what prompted me to reply. It seemed straightforward to me and I was wondering what your query was really about.

 

 

[flying dog]

Well, as "straight forward" as it seems, I am still not 100% sure HOW the maths works to make both ways work.

 

If the other way works, it is WAY easier doing the "other way" rather than the documented way.

 

To make the other way work, all they would need to do is reverse the drift sides. Left = right and right = left.

 

Rather easy/simple.