Kriegsmarine Angriffscheibe Handbuch

[Pisces]

Originally Posted by joegrundman

In the early version of the templates for that tool there was a silght error in the location of the two ship images labelled Vorh. Heck and Vorh. Bug, as the tool wasn't yet fully understood by us at subsim. Later Hitman managed to obtain the actual KM manual for the tool, and since then has shared how to use it with any who ask.These two features are intended to interact with the Vorhalt arm, that is the funny shaped wheel. The locations of the two boat images should be such that the short tails on each boat will neatly indicate a position on the Vorhalt wheel.Once you have an intercept course, and have gathered your necesssary data, you use slide rules to calculate the necessary lead angle (vorhalt) to hit the target. You then set the vorhalt arm to show the AOB of the target at the moment of firing. You then set the bearing indicator to show the correct lead angle on the vorhalt arm, taking into account whether it is a Bow (Bug) or Stern (Heck) shot, and read off the opposite side of the arm the course that you should follow to be able to shoot the target with a 000 gyro angle. Alternatively the difference between your course at the moment of firing and the indicated lead angle course is the gyro angle you should use

I see, the 'angriff kurs' pointer with those symbols that I printed out is indeed different from the pointer shown on the screenshot on the first post of your mod thread. The symbols in your mod are moved away from the center compared to mine, they are also moved outward in the final flash executable. But your's is indentical with mine regarding to the missing centerline, that is there in the flash executable. And your mod and mine has a black triangle at the tip, while the executable flash version (and the manual) has a red triangle. So they are all a little bit different versions. I printed the latest version of Hitman's kriegmarine whizwheel v1.1. As I noticed some other inaccuracies and cosmetic bits I will contact him for an update.

I'm not too happy about my transparent parts anyway. Because they are inktjet transparencies they have one rough side that makes air bubbles a certainty when laminating. Unfortunately the hinge is allready glued together.

[Pisces]

Originally Posted by klh

You may be on to something there. Joe's answer to your first question also gave me some ideas. It looks like I'll have to work on a version 3!

I have another tip for this manual. It involves angles smaller than 5.7 degrees (like torpedo lead/gyro) that the outer angle ring doesn't have. But it requires using a pointer tool too that isn't part of the disk set that Hitman made. Before assembly of my handheld disk was finnished I realised it was quite difficult to align a certain angle with a certain mark on the time disk. So I made a pointer tool myself. I took a long leftover strip of transparent sheet and drew a radial line on it, long enough to reach the edge of the angle disk. Made a fold there to make a U-shape and placed the non-radial-line end between the large and middle disk (to move freely ofcourse around the hinge). The radial-line-half spans across the yellow and time disk over to the hingepoint(again to move freely, not glued!). Hopefully I can convince Hitman to add one to the log-calculator side in another version.

The trick is as follows: I assume you have the middle and inner disks set in a certain way based on a previous 'small angle' calculation. And on one of them is a number that is pointing to a location on the angle disk that represents an angle smaller than 5.7 degrees (left of 90 degrees). The trick is first to 'memorize' this angle position 'in the disk' by aligning the extra pointer tool to it. Now you are free to move the middle wheel to use as a alternative angle wheel. Why? Because the sine of small angles is quite proportional to the angle itself. You should line up the outside 6000m mark on the yellow distance/speed disk to the 6 degrees angle mark on the darkbrown angle disk. And see where the extra pointer tool intersects the yellow disk scale. There is the angle that is smaller than 5.7 degrees. Note ofcourse!!, this angle would be below 5.7 degrees, but can just as easily mean below 0.57 or 0.057 based on the calculation that lead to it. The disks can't tell the difference between 0.01, 0.1, 1, or 10 and so on. You should know which one is right!

[klh]

Originally Posted by Pisces

But it requires using a pointer tool too that isn't part of the disk set that Hitman made. Before assembly of my handheld disk was finnished I realised it was quite difficult to align a certain angle with a certain mark on the time disk. So I made a pointer tool myself. I took a long leftover strip of transparent sheet and drew a radial line on it, long enough to reach the edge of the angle disk. Made a fold there to make a U-shape and placed the non-radial-line end between the large and middle disk (to move freely ofcourse around the hinge). The radial-line-half spans across the yellow and time disk over to the hingepoint(again to move freely, not glued!).

Interesting. Could you post a picture of that by any chance?

[Pisces]

I'm sure this will do.

[Puster Bill]

The problem with your idea Pisces is that the ST scale (ie., small values of Sine and Tangent) doesn't correspond exactly with the Sine scale.

For example, on my Pickett N200-ES Trig, the S and ST scales are next to each other.

6 degrees S and .6 degrees ST line up pretty much exactly. THere is a slight difference between 10 degrees S and 1 degree ST.

By the time you get to 2 degrees on the ST scale, you are at 20.5 on S and at 3 degrees you are at 31.5 on S. At 5 degrees ST, you are at 62 degrees S.

There should be a separate ST scale on the wheel if you are going to deal with small angle values.

[Pisces]

Originally Posted by Puster Bill

The problem with your idea Pisces is that the ST scale (ie., small values of Sine and Tangent) doesn't correspond exactly with the Sine scale.

For example, on my Pickett N200-ES Trig, the S and ST scales are next to each other.

6 degrees S and .6 degrees ST line up pretty much exactly. THere is a slight difference between 10 degrees S and 1 degree ST.

By the time you get to 2 degrees on the ST scale, you are at 20.5 on S and at 3 degrees you are at 31.5 on S. At 5 degrees ST, you are at 62 degrees S.

There should be a separate ST scale on the wheel if you are going to deal with small angle values.

I agree that it is going to be in-accurate, and a ST scale is missing. But I am seeing this as an approximation it in a counter-clockwise way (also, I was reffering to the Angriff scheibe, not a linear sliderule), while you are looking at it clockwise the way you describe it.

Since it's no problem calculating angles above 5.7-ish degrees, I suggested extending the angle scale to the left of 5.7 degrees only by crossing over to the meter scale on the yellow disk (when 6000m is aligned to 6 degrees). Once looking below 5.7 degrees I ignore the marks on the dark brown scale. I look where my free pointer is over the meter scale and take that as a good (enough) approximation. I mean, as much as my obsession with accuracy secretly desires it, we do not need sub-arc-minute (no pun intended) resolution, do we? Trust me, sin(x)/x becomes more linear the closer you get to x=0. The sine scale becomes an ordinary log scale the more you go counterclockwise (or left in linear rulers).

[ejhawk56]

Originally Posted by klh

You may be on to something there. Joe's answer to your first question also gave me some ideas. It looks like I'll have to work on a version 3!

Glad I didn't have enough ink to print off the new version yet...looks like more interesting things to come!

Very interesting discussions....now to go figure out what the hell you're all talking about:hmm:

[klh]

Originally Posted by ejhawk56

Glad I didn't have enough ink to print off the new version yet...looks like more interesting things to come!

Don't get too excited. It took me over a month to get version 2 out, and real life is as busy as ever. It will probably be a while before version 3 comes along.

[ejhawk56]

Originally Posted by klh

Don't get too excited. It took me over a month to get version 2 out, and real life is as busy as ever. It will probably be a while before version 3 comes along.

No problem KLH. Plenty for me to digest for now...RL tends to get in the way on this end too.

[klh]

I have published a new version of the Angriffscheibe Handbuch (version 3). You can find the link at the top of this thread, or on my filefront page.

This revision is a major rewrite (32 pages), and now includes 18 examples of how to use the disc. It is formatted to be printed into a booklet (with a front and back cover).

It incorporates some changes to our understanding of how the disc was likely used by the Kriegsmarine.

I must give special thanks and recognition to Joegrundman and Hitman for their help and advice.

If you haven't already, go full manual TDC and "be more aggressive"!

[jmr]

Just downloaded . . . wow what a big update! Thanks for this new and improved version, klh.

[Alyebard]

Just downloaded. You are a Master of Trigonometry . Superb work.

[SteveW1]

It looks like filefront has deleted the file any chance of reposting it please.

Steve

[Pisces]

I have uploaded it to my Filefront page to mirror.

http://files.filefront.com/Angriffss.../fileinfo.html

[klh]

Originally Posted by SteveW1

It looks like filefront has deleted the file any chance of reposting it please.

Steve

I've re-uploaded it to my FF page as well. Thanks for letting me know.