Slide Rule Targeting for SHIII/SHIV

[Vandecker]

I still can't get it, my biggest problem is i still don't understand what you mean by 'twenty' degrees. Do you meant I have to move the slide rule two little ticks in one direction? none of which add up to twenty in value, or that I have to move the slide rule to a certain 'value' of twenty indicated by the slide.

This step is also not very well illustrated by your photo as from what I can see you have not moved the slide by 'twenty' by either the ticks or value.

I attempted to use this method trying both the value and the tick method but both gave me angles of bearing that were clearly too low i.e: 025 when the target was clearly well above an AOB of 045.

Thanks for Writing this article by the way, I've been hunting round trying to find such an article for a while now since I knew dad still had his old slide rule hanging around.

[steinbeck]

Originally Posted by jmr

My brain is fried. Maybe it's because I don't remember my trig from YEARS ago or that I just suck at math but I'm getting inconsistent results with my rule. I need an idiot's guide to these things.

Go here.......http://oughtred.org/flyers/OS-ISRM_SlideRuleSeminar.pdf for a PDF
D/L


steinbeck..........

[MrSargyano]

Good rules to know Don1reed! The more ways I know to find a solution, the more options I have when I need to calculate one. Not to mention give myself a sanity check if necessary.

Steinbeck, I will make a point to go over the one you have suggested to Jmr before I finish reading the two I have chosen. I have at this point found alot of sites on the slide rules and downloaded a select few PDFs after having perused many. Ought to be fun if I could just stop reading these forums and playing the game long enough to read them . Fortunately, my in-game targeting has become sufficient enough that when I start practicing with the slide rule again, I will have a good point of reference.

Soon I will get rid of the box on the map (RFB w/o TMO) that marks the target locations. Wihtout that, things will get difficult once again. I use them to calculate AoB, speed, and verify solutions. All three of these things are easy as long as they are present. Even distance isn't terrible to calculate with them.

Measuring distance with the stadimeter (minutes of angle w/SCAF mod) will become critical at that point. SONAR will be my only available sanity check (that I know of) and it will not allways be available (surfaced) or sometimes even an option (DD's) let alone entirely accurate :rotfl:.

The challenge awaits.

Thanks ya'll,
Mr. Sargyano

PS I can tell allready this is going to be a great doc for me Steinbeck.

[Puster Bill]

Originally Posted by Vandecker

What is meant by 20 degrees between the 4 and the 7??

I have a proper engineering slide rule infront of me (my fathers from years back), and no matter how I move it so that the slide moves 20 degrees acording to the S table I get results that are at least a degree if not more different to yours. i.e 22 degrees at 7000 metres and 41 degrees at 4000 metres.

How do you calculate that 20 degrees onto the slide rule??

I'd have to see it to know for sure, but I have three rules, two I made and one that was manufactured, and they are all in agreement (within a certain amount).

When I align 23 degrees on the S scale to the second 4 on my A scale, then 43 degrees on the S scale lies directly below the 7 on the A scale.

You might have to use the D (or C) scale with the S scale on your rule, as I noted in my instructions the rule I was using has an S scale that is "double", ie., it goes from just under 40 minutes all the way up to 90 degrees, so I *HAVE* to use the A scale.

If you have a normal S scale that goes from just under 6 degrees up to 80 or 90 degrees, you can't match it against the A or B scale, you have to match it against the C or D scale.

Hope that helps.

EDIT: If you have a normal S scale and the target is coming close to right at you or moving almost directly away, you might have to use the ST scale, which would go from less than one degree up to about 5.5 degrees, give or take, against the C or D scale.