Excel target speed calculator

I'm using this pattern:-

http://www.sphere.bc.ca/test/build/yokota-loglog.pdf

Originally Posted by Puster Bill

Here is how it works:

You take observation 1, say, 7300 yards at bearing 220
Then, a few minutes later, observation 2, 6100 yards at bearing 213.

Subtract 213 from 220, giving 7 degrees.

that makes sense.

Originally Posted by Puster Bill

Fiddle with the S scale on the slide against the A scale until the distance between 6100 and 7300 on the A scale matches 7 degrees. In this case, it comes to about 52 degrees matching with 6100 (actually, 6.1 on the scale). That is the AOB at the second observation.

you say the distance between 6100 and 7300, do you mean 1200? (1.2 on the A scale)

where do you get the 52 degrees from? If i line up 7 on S with 6.1 on A i can find ~52 on the T2 scale. If i line 7 on S with 1.2 on A then i can't see anything like 52 (or even 5.2) lined up with 6.1

Originally Posted by Puster Bill

Without moving the slide, move the cursor along the S scale down to the 7 degree mark on the S scale. This will give the distance traveled on the A scale, in this case about 1,480 yards (it will actually read 1.48).

Now you've lost me totally. I haven't moved the slide (as requested) so as far as i can see, 7 on S still lines up with 6.1 on A. Where do i get the 1.48 from.

Originally Posted by Puster Bill

Now, you remembered to time the observations, right? If you are using a variant of the 3 minute 15 second rule, you are golden, as you can convert directly to knots.

14.8 knots in this case?

Originally Posted by Puster Bill

However, if you had to go take a dump or whatever between observations, and couldn't do it exactly, don't sweat it.

Lets say that you had to wait for 4 minutes, or 240 seconds, between observations. Align the distance, 1,480 yards on the A scale (again, actually 1.48) with the time in seconds on the B scale (actually, 2.4). We then read the speed in yards per second on the B scale under the 1's on the A scale, in this case 16.2 YPS (actually, it will read 1.62).

gotcha

Originally Posted by Puster Bill

To get knots, simply align the middle '1' on the B scale with 5.7 on the A scale. Slide the cursor to the speed in YPS, or 16.2 (1.62) in our example, on the B scale. You can then read the speed in knots on the A scale right under the cursor, or in this example 9.35 knots.

this is using the 1.62 to the Right of the middle "1", yes?

Originally Posted by Puster Bill

If you are doing your calculations in meters instead, you would use 5.2 on the A scale to give speed in knots.

You now have everything you need, distance, AOB, and speed in knots. You could print up a chart with common YPS/Knot equivalencies if you are lazy.

or make an excel spreadsheet to do it for me!


Thanks