Mobius' Dispatches from the Front

Nov. 12, 2018
There was a bug in NAAB that didn't re-initialize the shell factors after the first run.  Fixed.  Also, added a selection to display penetration in mm.  This changed the Armor and Gunnery analysis page.

Nov. 8, 2018
I added examples of WWII Russian tank guns.  Also I modified NAAB to change shell quality in case users on't agree with the default values.

Nov. 6, 2018
The Armor and Gunnery at the Copyright office appears to be real.  It is different than either o my copies and I can't explain why.  I added another page for it. 

Nov. 5, 2018
There was a bug in applying the drag coefficient in NaaB.   That has been fixed.
Also, noticed that both the Wikipedia and War Thunder is now posting penetration numbers for the 100mm BR-412/BR-412B and 122mm BR-471/BR-471 which are way out of the norm.   They say that the numbers represent US penetration standards.   But, I have never found US firing tables for these guns.  None that are from testing.  Several people have made them from calculations but they aren't true tested values.
Wiki 100mm
War ThunderWiki 122mm

Sept. 23, 2018
Rifle ballistics.  I'm taking on rifle ballistics for the German K98k and Russian Mosin-Nagant.
While this has little practical application for Panzer War as the table gets fiddlely at that scale it does work for Panzer Command.  As the bullets are used in the light squad machineguns this works for them as well. 

Sept. 3, 2018
Calculations on optics of sights.  Why did the British evaluation of light transmission of German TF-5b sight so much less than their evaluation of the Russian TMFD sight?

June 17, 2018
Wiki is wrong.  OK, yeah it often is.  But  US 76mm M1, M1A1, and M1A1C had 40:1 rifling twist. Only the M1A2 had the 32:1 twist.   3" M5 and M7 also retained the 40:1 twist. 
Updated the bomb table of NAAB2.1 with modern bomb GBU-39.

May 26, 2018
The NAAB2.1 program is changed slightly again.    I received an note from Nathan Okun saying that the elongation scaling should be limited to 18".   So this has been done.  There was another change made as HCWCLCR is updated to HCWCLCR5. Download NAAB 2.1 with bombing here

May 10, 2018
The NAAB2.1 program is changed slightly.   The diameter scaling is cut off at 20" right now.  One other idea may

be have max scaling linked to elongation.
Download NAAB 2.1 with bombing here


April 30, 2018
I'm just going to cut off the scaling a 16" until I find a better solution.   You can download the NAAB 2.1 with bombing here

April 23, 2018
Whoops, I'm having a problem with the bombing section.  Using HCWCLCR the program fails when the

bomb (shell) is too wide and the armor percent elongation is too low.   The scaling algorithm goes to hell.  Basically, it can multiply the NBL by 0 if the bomb is sufficiently wide as is the Tall Boy and Grand Slam and the percent elongation (PE) is lower than 25%.  No problem if the PE is 25% as the scaling algorithm goes to 1.
So here is the problem - the scaling equation.
IF ((PE < 25) AND (D > 8)) THEN NAVYBLM79 = NAVYBLM79 * (1 - (1 - SQRT(PE / 25)) * (D - 8) / 8).
So when the bomb diameter 'D' is 38" like in the Tallboy we have the multiplier = (1 - (1 - SQRT(PE / 25)) * (30) / 8).   Solving for PE we get.  8/30 = 1 - SQRT(PE /25) or  1-8/30 = sqrt(pe/25);   0.7333^2 = pe/25
Or PE = 13.444.   In this case  NAVYBLM79=NAVYBLM79 * 0.   I.e. NAVYBLM79 = 0.
Which means the Tallboy will penetrate an infinite thickness of pe=13.44% armor.
So wanting to see what the Tallboy will do to the Tirpitz with 'Wh' PE=18 deck armor I was surprised to find that it will penetrate over 50" from 18,000 ft. That is a little optimistic.


April 18, 2018
I thought I was done with the NAAB2.0 update but two things keep it going.   One is that it was requested that I add a bombing section.  This seemed a possibility by using homogeneous penetration calculations for deck armor.  Then use the ballistics from a free fall from the apogee of a ballistics curve.  This proved possible and the bombing section is in testing.   The other is that Nathan Okun said the program is missing the FaceHard 7.9 update.  I'm still looking into this as there are several sections of FH that are rewritten and I'd have to test my translation from BASIC. 
One difficulty I have with the bombing logic is what to do with GP/HE bombs when confronted with two armored decks.  With AP and SAP shells it is pretty easy.  Use the remaining velocity and exit angle from upper deck penetration to attack the lower deck.  Right now the GP/HE bomb attacks the upper deck with kinetic energy then attacks the lower deck with explosive energy.  But, that supposes that the bomb does not detonate in the space between decks.  Some decks have larger spaces than others.  This may not have an engineering solution but a probability solution.

April 11, 2018
One question that was asked was why is Face hard penetration more than homogeneous penetration.   Shouldn't it be harder to penetrate face hard armor?  I suppose it should be but a capped shell will penetrate more facehard armor but the cap slightly absorbs some energy in homogeneous armor.  At least that is what calculated armor penetration puts it.  Here is a link to a comparison of armor penetration for 76mm and 90mm tank guns.

April 8, 2018
So the Naval Armor and Ballistics program update is complete.  Link to NAAB2.0 download.

March 27, 2018
More work is being done on Naab 2.0 and further testing.  Here is a look at the documentation for the project.  Link

March 19, 2018
The update of NAaB 2.0 is winding down.    The project has taken longer than I hoped.  Now, working on stuff outside the last version.  Making up HE penetration.  There is a formula for that but I found it doesn't jive with my data.  I am trying to match it up with TM 9 1907 firing tables of concrete penetration.  If concrete is 1/15 the armor of armor.  Now there is some debate of the concrete to armor multiple so 1:15 is my compromise.  One online table has it