Complex Math (NAV) Problem

[Syllogism]

Without using a calculator (trig functions):

Does anyone know the quick mental-formula for determining the heading required to proceed from one point in space to another point in space when navigating off a single VOR?

Example:

What heading is required to go directly from the 090 radial 20 DME fix - to the 180 radial 70 DME fix?

I am at a total loss...?

 

[flyburg]

Don't know of any way to calculate, but do know how to visualize .

Not sure if I can explain it simply but here goes. Use your DG or HSI as reference tool. Use the radial with the largest distance first(180), locate it on the DG or HSI and picture the 70 dme fix on the outer limit of the display. ( this becomes your distance reference scale. From the center of the display to the outer limit is 70 miles).

No go to the 090 radial( picture it on the DG) and visualize where the 20 dme fix is on the DG( 2/7 from the center of the DG).

Now draw(visualize) a line through the two fixes you found on the DG. This is the course you have to fly to get from the one to the other, move/visualize this line to the center of the display and you can find the heading to fly.

This all without taking wind corrections into account.

Hope it makes sense, I could show it to you in two seconds, but to explain it in writing is a little more difficult.

Without using a calculator (trig functions):

Does anyone know the quick mental-formula for determining the heading required to proceed from one point in space to another point in space when navigating off a single VOR?

Example:

What heading is required to go directly from the 090 radial 20 DME fix - to the 180 radial 70 DME fix?

I am at a total loss...?

 

[Freight Dawg]

Hopefully this is classroom exercise in futility and not a realistic scenario. I hate to break it to you but we have FMS for this kinda stuff these days. Hopefully there is no wind to have to worry about calculating the correction for either.

Here is a hint, draw a square 2 units across and seven units down, now draw a line corner to corner. Remember the rules of triangles.

 

[340drvr]

Maybe use the 1-in-60 rule? 1 degree of deviation at 60nm is 1 nm "off course". If your example was the 180 radial at 60 dme, then the acute angle of the triangle would be simply 20 deg., making the heading 200. Multiples of 60 for the long leg are easy, but, with the 70dme fix, then it will be "6/7 in 70" or such. As this is an old fashioned problem, it was probably meant to be figured with a whiz wheel, easily set up for "divide by 60" problems. But, I couldn't begin to tell you how to do it at this point, my E6B is buried, somewhere, I think, for 10-plus years.

 

[Skippy]

U could only do a course unless u knew the exact wind.

To get the course would be easy using a grid and some type of uniform measuring unit for the distance. Then drawcourse and use a protractor and get angle and course, plug in wind and get heading. Its math,atecially possible, just note feasable U could eyeball it and say itsa 200 course then apply heading....but eally want to do that?
!
!
---------------$ ( 090/20)
!
!
!
$(180/70)

 

[pilotyip]

Don't know of any way to calculate, but do know how to visualize .

Not sure if I can explain it simply but here goes. Use your DG or HSI as reference tool. Use the radial with the largest distance first(180), locate it on the DG or HSI and picture the 70 dme fix on the outer limit of the display. ( this becomes your distance reference scale. From the center of the display to the outer limit is 70 miles).

No go to the 090 radial( picture it on the DG) and visualize where the 20 dme fix is on the DG( 2/7 from the center of the DG).

Now draw(visualize) a line through the two fixes you found on the DG. This is the course you have to fly to get from the one to the other, move/visualize this line to the center of the display and you can find the heading to fly.

This all without taking wind corrections into account.

Hope it makes sense, I could show it to you in two seconds, but to explain it in writing is a little more difficult.

That is the way we were taught to go from one Tacan fix to another. Used just a while back going into SLN, out of radar contact, cleared "Proceed present position to the 12 DME ARC on the SLN 270 radial", Eye balled it about 100 miles out, took a heading hit the radial and the DME fix within two miles. Don't need no stinkin FMS, or plotting board.

 

[Clutch]

The answer is a course of 196 degrees.


Pythagorean theorum and whatnot.

 

[Skippy]

The answer is a course of 196 degrees.


Pythagorean theorum and whatnot.

I said 200 , what do i win?

 

[Clutch]

I said 200 , what do i win?

A new E6b!

 

[brokeflyer]

I said 200 , what do i win?

nothing because you were wrong....the answer is 196.