RE: High Velocity AP round hit-zones (Full Version)

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Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 5:49:42 AM)

I don't like posting some of this research as the unique stuff always seems to end up over at the WOT forum.




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 5:57:16 AM)

So you are using data with ranging errors to check dispersion? I don't follow that at all.

Hopefully you can check my work and see if you agree.

The thread is actually in regards to using zone-fire to bypass these ranging errors. Perhaps this side discussion would be better in a separate thread?




Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 3:54:57 PM)

quote:

ORIGINAL: Yoozername
So you are using data with ranging errors to check dispersion? I don't follow that at all.
No. To check the final output. The dispersion is needed for the calculations but unless the formula produces real world results it's academic.

quote:

ORIGINAL: Yoozername
Hopefully you can check my work and see if you agree.
The thread is actually in regards to using zone-fire to bypass these ranging errors. Perhaps this side discussion would be better in a separate thread?
Give me some examples of guns with zones and I'll run the odds through my ballistics program.




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 5:17:19 PM)

WO 291/180
Do you have the conditions and methodology used in this report? What is the ranging error used? How many rounds were fired for each ranged test? What dispersion information is there? Basically you are saying that your program can achieve agreement with these two guns against TigerIe sized targets under the conditions tested? (stationary, hull up and down)




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 5:34:04 PM)

quote:

Give me some examples of guns with zones and I'll run the odds through my ballistics program.


Run the program for the conditions in the first post. That is, 75mmL48 firing APCR. T34/85 stationary face-on @300m. From 0-500 meters, what are the probabilities of being hit with 30% range estimation error in both directions (210m and 390m). If you could, explain how it's calculated in words if you do not want to reveal too much.




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 6:24:51 PM)

I found the report in an old post
quote:

WW2 hit probabilities
WO 291/180, Accuracy of anti-tank gunnery
Ranges in yards, target assumed to be Pz VI size.
Probability (%) of hitting static hull-up target with first round:
Gun OK for... 500 1000 1500 2000 2500
6 pdr line 100 100 96 87
range 87 33 13 3
both (hit) 87 33 12 3
17 pdr line 100 100 100 98 93
range 98 46 20 10 5
both (hit) 98 46 20 10 5
Probability (%) of hitting static hull-up target after first round:
Gun 500 1000 1500 2000 2500
6 pdr 100 86 59 41
17 pdr 100 94 71 50 36
Probability (%) of hitting moving target (direct-crossing at 15 mph) after first round:
Gun 500 1000 1500 2000 2500
17 pdr 86 48 26(e) 16
Probability (%) of hitting hull-down target with first round:
Gun 500 1000
17 pdr 59 18
Probability (%) of hitting static hull-down target after first round:
Gun 500 1000 1500 2000 2500
6 pdr 85 43 22 14
17 pdr 88 51 29 18 12
Comments and corrections
These values are those plotted on the graphs in the report; the value marked (e) is interpolated from
other data points. The overall shape of the fitted curves in each case is sinusoidal.
This report recommends that the maximum range of engagement for 6-pdr and 17-pdr ATk guns be
considered 800 and 1000 yards respectively. The criteria stated for maximum range of engagement for a
statically-sited ATk gun are:
50% chance of first-round hit on a static hull-up target;
90% chance of subsequent rounds hitting a static hull-up target;
50% hits on a hull-up direct-crossing target moving at 15 mph after MPI roughly corrected;
50% hits on a static hull-down target after MPI roughly corrected.
The first table clearly shows that errors in range have a much more important effect on accuracy than
errors in line.




Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 6:39:02 PM)

The block is using the unadjusted Bird-Livingston formula.
The range number is the target distance. The aim is the point of aim with error.
The P(Hit)% is the percent chance of hitting.
Firing height=7ft.


[image]local://upfiles/21308/725580B6BDDC478D8CBA7E80E26E6D94.jpg[/image]




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 6:56:40 PM)

Is that 30% or 20%? Also, I believe a Hetzer had a 1 meter gun height



Example
Range 411
Aim 505

505-411=94m

94/411=0.2287

It looks like 22.9% over-range to me




Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 7:49:07 PM)

It's the way they handle the range error. It is the std deviation of the error. So 30% it would be 22.7%.




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 8:25:22 PM)

Most range error data just states +/- XX meters.

From the report WO 291/180...

quote:

These values are those plotted on the graphs in the report; the value marked (e) is interpolated from
other data points. The overall shape of the fitted curves in each case is sinusoidal.


I suppose that if it sinusoidal, it might look like this...

[image]local://upfiles/20015/7B88DC6FA8174C909DC4ECDD2B2F7805.jpg[/image]




Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 9:32:56 PM)

This curve too is sinusoidal. I ran a 30% error as if it were the std. dev.
Also, changed the gun firing height to 4'.
The curve is from the data.


[image]local://upfiles/21308/9C5813DC2A234B509F21233550D6C209.jpg[/image]




Mobius -> RE: High Velocity AP round hit-zones (12/3/2012 10:24:56 PM)

This what a sinusoidal accuracy curve looks like.

[image]local://upfiles/21308/E6AE905346F342F3BADD4F811EA16EFA.jpg[/image]




Yoozername -> RE: High Velocity AP round hit-zones (12/3/2012 11:22:32 PM)

I assume you have a standard target height/width? 2.5m x 2m?

Also, the 'Over(m)', I take this is vertical dispersion at the actual range?




Yoozername -> RE: High Velocity AP round hit-zones (12/4/2012 12:29:39 AM)


[image]local://upfiles/21308/9C5813DC2A234B509F21233550D6C209.jpg[/image]
[/quote]

Can you run this with the following numbers:

Range: 183, 229, 274= Aim 250
Range: 320.......640= Aim 500
Range: 686.......869= Aim 775




Mobius -> RE: High Velocity AP round hit-zones (12/4/2012 2:19:07 AM)

I can't give it a fixed aim number. It goes by fixed range error. So I have to give it a different range error for each row.


[image]local://upfiles/21308/14B259649B67488F806DFB81026DFA02.jpg[/image]




Yoozername -> RE: High Velocity AP round hit-zones (12/4/2012 3:19:05 AM)

I suppose you could just change the numbers a little. That is, just enter:

183 249
229 250
274 251
320 252

366 496
411 497
457 498
503 499
549 500
594 501
640 502

686 774
732 775
777 776
823 777
869 778

Edit: Can you just enter the minimum range error??? My whole point is that it should not matter. I am not sure if you are following this.





Mobius -> RE: High Velocity AP round hit-zones (12/4/2012 4:30:12 AM)

When the range and the aim point are only a few meters apart it reduces down to just the dispersion inaccuracy.

[image]local://upfiles/21308/4BA1898E93FA43F39C2ED7C2DE90E52B.jpg[/image]




Yoozername -> RE: High Velocity AP round hit-zones (12/4/2012 4:42:02 AM)

What happens if you inpt these numbers?
quote:

ORIGINAL: Yoozername

I suppose you could just change the numbers a little. That is, just enter:

183 249
229 250
274 251
320 252

366 496
411 497
457 498
503 499
549 500
594 501
640 502

686 774
732 775
777 776
823 777
869 778

Edit: Can you just enter the minimum range error??? My whole point is that it should not matter. I am not sure if you are following this.







Mobius -> RE: High Velocity AP round hit-zones (12/4/2012 12:02:07 PM)

Right now it only computes if the aim is greater or equal to the range. In a short aim when the projectile hits the ground the run is over. To work with the formula it would have to be made to continue on and pass beneath the target to find the distance from the path to the center of the target.

Here are a subset of what I can find.

[image]local://upfiles/21308/ECC653D501AC4B2190A6275BE4C2EDB2.jpg[/image]




Mobius -> RE: High Velocity AP round hit-zones (12/4/2012 2:34:28 PM)

I can find precious few live fire accuracy tests. All I do find are British. Though the two donít agree with each other. This table has an unknown target size. Assuming it is Panzer IV sized I ran another test with different gun heights and 25% ranging error. 17-pdr and 75mm match to a high degree. The 6-pdr doesnít match the WO 291/180. And the APDS values seem highly optimistic.

[image]local://upfiles/21308/C625EBED6DA741888A619EA924921DC9.jpg[/image]




Yoozername -> RE: High Velocity AP round hit-zones (12/4/2012 3:19:50 PM)

I think I have some 17 pdr. info also.

How about entering 425 aim up to 411 range, enter 650 aim up till 640 range and 875 up to 869 range? That should work even though it isn't exactly the zone fire I would want. It could demonstrate some principles.




Mobius -> RE: High Velocity AP round hit-zones (12/5/2012 1:41:42 AM)

411-425=100%
640-650=89.8%
869-875=76.7%




Mobius -> RE: High Velocity AP round hit-zones (12/5/2012 2:24:16 PM)

Here an interesting report on range estimation.
http://www.dtic.mil/dtic/tr/fulltext/u2/a132616.pdf




Yoozername -> RE: High Velocity AP round hit-zones (12/5/2012 4:26:28 PM)

quote:

ORIGINAL: Mobius

When the range and the aim point are only a few meters apart it reduces down to just the dispersion inaccuracy.

[image]local://upfiles/21308/4BA1898E93FA43F39C2ED7C2DE90E52B.jpg[/image]


So, if I understand this correctly, you are saying that this is for a German 7,5cmL48 gun firing APCBC or APCR?

This data shows a weapon with no range error? Target size 2.5m by 2m?

Just for reference:

75L48 TUNGSTEN CORE
100m....0.1m/0.0m
300m....0.2m/0.1m
500m....0.3m/0.3m
800m....0.5m/0.4m
1000m..0.7m/0.6m

75L48 APCBC
100m....0.1m/0.0m
300m....0.2m/0.2m
500m....0.3m/0.2m
800m....0.4m/0.4m
1000m..0.6m/0.5m





Mobius -> RE: High Velocity AP round hit-zones (12/5/2012 7:05:48 PM)

quote:

ORIGINAL: Yoozername
So, if I understand this correctly, you are saying that this is for a German 7,5cmL48 gun firing APCBC or APCR?
APCR

quote:

ORIGINAL: Yoozername
This data shows a weapon with no range error? Target size 2.5m by 2m?

Just for reference:

75L48 TUNGSTEN CORE
100m....0.1m/0.0m
300m....0.2m/0.1m
500m....0.3m/0.3m
800m....0.5m/0.4m
1000m..0.7m/0.6m

75L48 APCBC
100m....0.1m/0.0m
300m....0.2m/0.2m
500m....0.3m/0.2m
800m....0.4m/0.4m
1000m..0.6m/0.5m
It doesn't matter the target size or range error, it's a gun variable.





Yoozername -> RE: High Velocity AP round hit-zones (12/5/2012 10:59:56 PM)

So, I assume that P(Hit) is a percentage to hit something? Does that something have any size characteristics? Or it could be a KV-2 or a lend lease jeep?




Mobius -> RE: High Velocity AP round hit-zones (12/6/2012 1:40:43 AM)

For the German projectiles it is the size of a T-34/76 from the front. I take a cue from the WO tests and use the most common size of the enemy tank.




Yoozername -> RE: High Velocity AP round hit-zones (12/6/2012 5:39:30 PM)

At 800 meters, you have about 1 out of 5 APCR shots missing the target T34 (I assume this is first round accuracy on a known range). The vertical 50% dispersion is 0.5 meters at 800 meters. Even if I use 3 sigma conversion, it is just barely over the target height. About 2.28m. The 0.14 meter distance, both over and under the target, represents, what...a 4-5%?





Mobius -> RE: High Velocity AP round hit-zones (12/6/2012 6:44:18 PM)

It is the first shot 30% range error. Firing at 1040m will be 1.65m above the center of the target at 800m.




Yoozername -> RE: High Velocity AP round hit-zones (12/6/2012 6:47:38 PM)

This is the data I am referring to.
quote:

ORIGINAL: Mobius

When the range and the aim point are only a few meters apart it reduces down to just the dispersion inaccuracy.

[image]local://upfiles/21308/4BA1898E93FA43F39C2ED7C2DE90E52B.jpg[/image]





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