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Old 09-27-21, 08:16 PM   #1
shoiga
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Plz someone teach me how to determine the lead angle for a perpendicular attack with 0° torpedo gyro angle by Angriffsscheibe!
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Old 09-28-21, 09:01 AM   #2
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There are many threads about this subject. Try a google for fast 90 attack, i.e.
Wazoo did a good one too a long time ago.
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Old 09-28-21, 12:57 PM   #3
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Search the subsim downloads for Angriffscheibe Handbuch. It should come up with a community created PDF in RAR archive format. It explains how you can do various calculations with it. (can also be found in the bottom link in my signature)


Just be aware, across-targettrack/perpendicular or 0 gyro angle is not a requirement to get torpedoes on target. Just that is makes the best odds of succes. And are in no way actually part of the lead angle calculation. Only target speed, torpedo speed and AOB through the sine rule : opposite side/sine (angle)=constant
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Old 09-28-21, 04:37 PM   #4
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Kriegsmarine Attack Disc Manual:


https://maikhaas.synology.me:5001/fs...H3%20TUTORIALS
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Old 09-30-21, 05:19 PM   #5
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Plissken: The version on my site seems to be from March 2008. And has better images. Don't know if that synology is yours, but you might want to consider adding it too:

http://ricojansen.nl/downloads/Angri...Handbuch_3.rar
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Old 10-01-21, 04:18 PM   #6
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Quote:
Originally Posted by Pisces View Post
Plissken: The version on my site seems to be from March 2008. And has better images. Don't know if that synology is yours, but you might want to consider adding it too:

http://ricojansen.nl/downloads/Angri...Handbuch_3.rar



Thank you,i will take it and yes,the synology is mine.



PS: It's the same as mine,but yours are in Color.Anyway I'll put your Version on my Server.
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Old 10-03-21, 06:06 AM   #7
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Just keep in mind that the attack disc itself could not compute this, it only ever showed relative angular relationships. The reverse side however, which is not historical to the Germans, is a logarithmic slide rule that allows you to compute trigonometry problems such as this. It should be said though that computing lead angle for a perpendicular attack using that slide rule is somewhat laborious, because it does not include a tangent scale. Sub Buddy app, however, does (highly recommended).

Something like this is very easy to calculate with a calculator. For a perpendicular attack, lead angle = arctan ( target speed / torpedo speed).

So on a calculator take target speed divided by torpedo speed, and then press “tan-1”.
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Old 10-03-21, 09:20 AM   #8
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Quote:
Originally Posted by derstosstrupp View Post
.... It should be said though that computing lead angle for a perpendicular attack using that slide rule is somewhat laborious, because it does not include a tangent scale. Sub Buddy app, however, does (highly recommended).

Something like this is very easy to calculate with a calculator. For a perpendicular attack, lead angle = arctan ( target speed / torpedo speed).

So on a calculator take target speed divided by torpedo speed, and then press “tan-1”.
Meh, his AoB across the torpedo speed, then the lead angle is across the target speed. When you assume the AOB is 90 in perpendicular setupo then this is close enough.
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Old 10-03-21, 09:21 AM   #9
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1. Get ahead of the convoy.
2. Set course 90 degrees to convoy's course.
3. Sink ships.
4. Laugh at the wimpy escorts.
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Old 10-03-21, 02:38 PM   #10
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Quote:
Originally Posted by Pisces View Post
Meh, his AoB across the torpedo speed, then the lead angle is across the target speed. When you assume the AOB is 90 in perpendicular setupo then this is close enough.
Well, say the target speed is 15 kn, shooting a 30 knot torpedo. If you just assume 90 AOB for a perpendicular setup, that is going to give you a lead angle of 30. When in reality using the correct formula for a perpendicular lead angle, yields 26.6. That’s a big difference depending on the range.

There are times when “close enough” is fine, but unless somebody is told that close enough only applies at close range, they would be led astray.

Also easily solvable using vector analysis. Using the fact pattern above, draw a line on the map 30 km long straight up. Draw a line going from the top end of that line but perpendicular, 15 km long. Now draw the third leg of the triangle and measure the angle at the bottom, your lead angle. Allows you to quickly figure out your lead angle for any desired track angle.
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Old 10-04-21, 10:37 AM   #11
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Quote:
Originally Posted by derstosstrupp View Post
Well, say the target speed is 15 kn, shooting a 30 knot torpedo. If you just assume 90 AOB for a perpendicular setup, that is going to give you a lead angle of 30. When in reality using the correct formula for a perpendicular lead angle, yields 26.6. That’s a big difference depending on the range.

There are times when “close enough” is fine, but unless somebody is told that close enough only applies at close range, they would be led astray.

Also easily solvable using vector analysis. Using the fact pattern above, draw a line on the map 30 km long straight up. Draw a line going from the top end of that line but perpendicular, 15 km long. Now draw the third leg of the triangle and measure the angle at the bottom, your lead angle. Allows you to quickly figure out your lead angle for any desired track angle.
Ok, but you can iteratively approximate it more accurately with repeated steps.

Assume AOB =90 ; Torpedo speed is 30 kts ; Target speed is 15 kts. > Leadangle =30

That means the AOB at firing time should be 60 instead. So align torpedo speed to angle 60: Now lead angle becomes 25.5 degrees for 15kts target speed.

That means the AOB at firing time should be 64.5 instead. So align torpedo speed to angle 64.5: Now lead angle becomes 26.75 for 15kts target speed.

That means the AOB at firing time should be 63.23 instead. So align torpedospeed to angle 63.25: Now lead angle becomes 26.5 for 15 kts target speed.

That means the AOB at firing time should be 63.5 instead. So align torpedo speed to angle 63.5: Now lead angle becomes very close to 26.5 again. No need to continue now. (I did this on my handheld template Attackdisk, reading and disk setting accuracy is getting the better of you beyond this point.)
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Old 10-04-21, 11:02 AM   #12
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Oh no I understand that, hence why I said it’s a little more of a laborious process. If it had a tan scale, would be easier. Ultimately the easiest I find if not wanting to use a calculator is vector analysis.
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Old 10-04-21, 11:54 AM   #13
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Math, smath Once I know the target speed and I'm at 90 degrees to it, I just zero the uzo/scope, put the target course direction (port/starboard) in the tdc and sink it.
Beats my head exploding anyway.
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