[CLOSED] M61 Dispersion

[SonofEil]

bump.

 

Also, does changing this make you no longer IC compliant?

 

Correct. No multiplayer with a corrected cannon, IC will get you.

[Groove]

Dear all,

 

i will point the thread to the apropriate people.

[Eldur]

Then please don't forget the GAU-8 while you're at it, it's also set to spread 22 mils and should be less

[DUSTY]

Dear all,

 

i will point the thread to the apropriate people.

 

 

Many thanks!

[Impact]

So do we get an update on this issue? It is such an easy fix, just one number to change. If there is a confirmation by the military that the M61s dispersion is truly that bad, okay. But it just seems too much.

 

Modern fighter jets get many hours of maintenance after every flight, someone should notice when the screws attaching the gun to the plane are loose and tighten them up a bit.

[Impact]

[iNVESTIGATING] M61 Dispersion

 

The gun of the Hornet seems to dispersing too much. So I did some research and came upon this video:

 

 

The dispersion should be at 8 mil so the value inside the files of DCS seems to be much higher.

In ..Eagle DynamicsDCS World OpenBetaScriptsDatabaseWeaponsshell_table.lua we can see that for each shell, the value is at 22 mil (Da0) which is significantly higher and leads to the high dispersion.

 

shell("M61_20_HE", _("M61_20_HE"), {

model_name = "tracer_bullet_yellow",

v0 = 1050.0,

Dv0 = 0.0060,

Da0 = 0.0022,

Da1 = 0.0,

mass = 0.110,

round_mass = 0.349,

explosive = 0.110, -- 0.0170 kg in real

life_time = 30,

caliber = 20.0,

s = 0.0,

j = 0.0,

l = 0.0,

charTime = 0,

cx = {0.5,1.27,0.70,0.200,2.30},

k1 = 2.0e-08,

tracer_off = 3,

scale_tracer = 1,

 

name = "20mm HE",

 

cartridge = 0,

});

 

shell("M61_20_HE_INVIS", _("M61_20_HE_INVIS"), {

model_name = "tracer_bullet_yellow",

v0 = 1050.0,

Dv0 = 0.0060,

Da0 = 0.0022,

Da1 = 0.0,

mass = 0.110,

round_mass = 0.349,

explosive = 0.110, -- 0.0170 kg in real

life_time = 30,

caliber = 20.0,

s = 0.0,

j = 0.0,

l = 0.0,

charTime = 0,

cx = {0.5,1.27,0.70,0.200,2.30},

k1 = 2.0e-08,

tracer_off = -100,

scale_tracer = 0,

name = "20mm HE",

cartridge = 0,

});

 

shell("M61_20_AP", _("M61_20_AP"), {

model_name = "tracer_bullet_white",

v0 = 1050.0,

Dv0 = 0.0060,

Da0 = 0.0022,

Da1 = 0.0,

mass = 0.110,

round_mass = 0.349,

explosive = 0.0,

life_time = 30,

caliber = 20.0,

s = 0.0,

j = 0.0,

l = 0.0,

charTime = 0,

cx = {0.5,1.27,0.70,0.200,2.30},

k1 = 2.0e-08,

tracer_off = 3,

scale_tracer = 1,

 

name = "20mm AP",

 

cartridge = 0,

});

 

I changed this to 0.0008 and now it seems to work just like in reallife. But this can't be used for multiplayer as the integrity check kicks me out.

 

Please fix this.

Edited June 10, 2019 by NineLine

[RightStuff]

Known and reported issue:

https://forums.eagle.ru/showthread.php?t=211966

 

No idea why it cannot be implemented.

Technically - as you mentioned - it's a piece of cake.

[Yo-Yo]

The gun of the Hornet seems to dispersing too much. So I did some research and came upon this video:

 

 

The dispersion should be at 8 mil so the value inside the files of DCS seems to be much higher.

In ..Eagle DynamicsDCS World OpenBetaScriptsDatabaseWeaponsshell_table.lua we can see that for each shell, the value is at 22 mil (Da0) which is significantly higher and leads to the high dispersion.

 

 

 

I changed this to 0.0008 and now it seems to work just like in reallife. But this can't be used for multiplayer as the integrity check kicks me out.

 

Please fix this.

I wonder how you turn 8 mils (0.008 ) to 0.0008 - what math was behind it?

[Yo-Yo]

And finally: trying to critisize and CHANGE the values - do you know exactly what kind of dispersion units is in the file: sigma, median, circle 80%, circle 90%, whatever?

[Sergeant_Hamlet]

ED has stated many times in the past that they change many details about weapons because they want DCS to be unreliable as a training platform for weapons employment. That's why it hasn't been fixed despite having been noticed as far back as the early warthog days.

[Yo-Yo]

ED has stated many times in the past that they change many details about weapons because they want DCS to be unreliable as a training platform for weapons employment. That's why it hasn't been fixed despite having been noticed as far back as the early warthog days.

 

Your statement is deeply wrong in regards of dispersion.

[RightStuff]

ED has stated many times in the past that they change many details about weapons because they want DCS to be unreliable as a training platform for weapons employment. That's why it hasn't been fixed despite having been noticed as far back as the early warthog days.

 

First time I am reading this kind of reason for "not going to fix".

May you have link to a post where exactly this was stated the first time or later on?

 

Edit; Kinda sniped by Yo-Yo.

Edited June 10, 2019 by RightStuff

[Sergeant_Hamlet]

First time I am reading this kind of reason for "not going to fix".

May you have link to a post where exactly this was stated the first time or later on?

 

I'm trying to find it. Could be I just thought I read it. My memory is as fallible as any other human being. I'll keep digging and report back if I find it. Burden-of-proof and all that.

Edited June 10, 2019 by Sergeant_Hamlet

[Impact]

I wonder how you turn 8 mils (0.008 ) to 0.0008 - what math was behind it?

 

There are other ammunitions like the 2A42 cannon of the BMP, and technical documentation hints at a dispersion of 4 mils (https://thesovietarmourblog.blogspot.com/2016/05/bmp-2.html : "Alternatively, a figure of ∼3 meters at a distance of 1000 m can be expressed as a dispersion of 3 mils. This matches the dispersion of 3-4 mils as claimed by technical literature.")

 

And in the file we have these settings:

 

shell("2A42_30_AP", _("2A42_30_AP"), {

model_name = "tracer_bullet_red",

v0 = 990.0,

Dv0 = 0.0081,

Da0 = 0.0004,

Da1 = 0.0,

mass = 0.390,

round_mass = 0.98,

explosive = 0.0000,

life_time = 30,

caliber = 30.0,

s = 0.0,

j = 0.0,

l = 0.0,

charTime = 0,

cx = {1.0,0.66,0.29,0.214,2.98},

k1 = 5.5e-09,

tracer_off = 9,

scale_tracer = 1,

 

name = "30mm AP",

 

cartridge = 0,

});

 

This seemed to be correct, so I tried it out for the M61. 0.008 > 0.0022 so the dispersion is 4 times as large, so it should be 0.0008. It just feels right, I have flewn other simulators over the year including Falcon 4.0, Janes F/A-18, Graphsims Hornet titles, F/A22 Total Air War, and they all feel like they have a similar dispersion. Try playing these and you will notice the difference.

 

edit: I checked out the M197 (https://www.gd-ots.com/armaments/aircraft-guns-gun-systems/m197/) and its' dispersion is the same as the M61 at 8 milliradians. And in the file it is 10 milliradians, which is okay for a gun that was used in combat. If the M61 gets 22 milliradians, why doesn't the M197 get the same treatment?

 

ED has stated many times in the past that they change many details about weapons because they want DCS to be unreliable as a training platform for weapons employment. That's why it hasn't been fixed despite having been noticed as far back as the early warthog days.

 

So why did they allow the F-14 from Heatblur to have the correct settings? Why is the GSh-30-1 of the MiG29 and Su27/33 allowed to have 5 mils?

If that is truly the reason, why even make a simulator? Why should they fix the radar issues, they could simply say "Let the radar stay broken, we don't want anyone to know how to use it if they somehow get their hands on an F/A-18C without a contract with the government of the USA".

Edited June 10, 2019 by Impact

[Yo-Yo]

There are other ammunitions like the 2A42 cannon of the BMP, and technical documentation hints at a dispersion of 4 mils (https://thesovietarmourblog.blogspot.com/2016/05/bmp-2.html : "Alternatively, a figure of ∼3 meters at a distance of 1000 m can be expressed as a dispersion of 3 mils. This matches the dispersion of 3-4 mils as claimed by technical literature.")

 

And in the file we have these settings:

 

 

 

This seemed to be correct, so I tried it out for the M61. 0.008 > 0.0022 so the dispersion is 4 times as large, so it should be 0.0008. It just feels right, I have flewn other simulators over the year including Falcon 4.0, Janes F/A-18, Graphsims Hornet titles, F/A22 Total Air War, and they all feel like they have a similar dispersion. Try playing these and you will notice the difference.

 

edit: I checked out the M197 (https://www.gd-ots.com/armaments/aircraft-guns-gun-systems/m197/) and its' dispersion is the same as the M61 at 8 milliradians. And in the file it is 10 milliradians, which is okay for a gun that was used in combat. If the M61 gets 22 milliradians, why doesn't the M197 get the same treatment?

 

 

 

So why did they allow the F-14 from Heatblur to have the correct settings? Why is the GSh-30-1 of the MiG29 and Su27/33 allowed to have 5 mils?

If that is truly the reason, why even make a simulator? Why should they fix the radar issues, they could simply say "Let the radar stay broken, we don't want anyone to know how to use it if they somehow get their hands on an F/A-18C without a contract with the government of the USA".

 

Your estimations are quite rough based on "3 mils for 2A42" . 3 mils is close to this value, but it gives an opportunity to understand what is used as a measure of dispersion.

As the ratio is close to 8, any military can say that it is MEDIAN - app 8 times less then full dispersion (or diameter).

So, 0.0022 will give about 17.5 mils. Why it was choosen? There was an information that the cannon has different barrel clamps to obtain different dispersion patterns. Gatling guns due to their principles can not have the same dispersion as a gun with fixed barrel, but for the guns with high rate of fire the certain increased dispersion is better giving more hit probability.

 

If you watched the video where F-18 shot at the target, you can see that due to aiming mistakes (pilot, aiming system, wind, etc) the target is hit only with few shells. If the cone was less - it would miss.

[Impact]

Your estimations are quite rough based on "3 mils for 2A42" . 3 mils is close to this value, but it gives an opportunity to understand what is used as a measure of dispersion.

As the ratio is close to 8, any military can say that it is MEDIAN - app 8 times less then full dispersion (or diameter).

So, 0.0022 will give about 17.5 mils. Why it was choosen? There was an information that the cannon has different barrel clamps to obtain different dispersion patterns. Gatling guns due to their principles can not have the same dispersion as a gun with fixed barrel, but for the guns with high rate of fire the certain increased dispersion is better giving more hit probability.

 

If you watched the video where F-18 shot at the target, you can see that due to aiming mistakes (pilot, aiming system, wind, etc) the target is hit only with few shells. If the cone was less - it would miss.

 

Then why is the M197, a rotating multiple barreled gun, still having only 0.0010 while the M61, also a rotating multiple barreled gun, having 0.0022?

And you didn't address the point why the F14 of Heatblur is allowed to have the better and seamingly correct settings?

[Contact409]

previous thread with bug report was closed but no update from ED side....

[Yo-Yo]

Then why is the M197, a rotating multiple barreled gun, still having only 0.0010 while the M61, also a rotating multiple barreled gun, having 0.0022?

And you didn't address the point why the F14 of Heatblur is allowed to have the better and seamingly correct settings?

 

We can not answer for 3rd party - it's up to them. As well as for flight performance.

 

Regarding M197 - because it was presumed that it does not use intentionally increased dispersion and has typical 0.008 you desired and as it is specified in

https://www.gd-ots.com/wp-content/uploads/2017/11/M-197.pdf

[Impact]

We can not answer for 3rd party - it's up to them. As well as for flight performance.

 

Regarding M197 - because it was presumed that it does not use intentionally increased dispersion and has typical 0.008 you desired and as it is specified in

https://www.gd-ots.com/wp-content/uploads/2017/11/M-197.pdf

 

The M61 doesn't use increased dispersion either.

https://www.gd-ots.com/armaments/aircraft-guns-gun-systems/m61a1/

 

Where do you get the information about clamps for different dispersion patterns? I can't find anything.

I can find something about the 30mm GAU8 having different dispersion patterns depending on the ground attack mission. In case there are presumably soft targets and for supression of enemy troops a wider disperion is used (but only 16 mil). For a 20mm cannon which is used for air-to-air combat it just doesn't make sense to have a wider spread.

Edited June 10, 2019 by Impact

[Aries144]

While the clamps are mentioned, there is no evidence they were used operationally. They appear to have been an experimental option that was never used.

 

Please examine the video evidence presented which displays an M61 test fired. 8 mil performance is observed.

[MonnieRock]

Hello Everyone,

 

I am not a pilot, nor do I have any experience with these weapon systems. In this thread, there are pilots with real world experience commenting on the situation. I would have to say that means a lot to me to hear their points and consider them a SME.

 

The thread is here and listed as [REPORTED]

 

[REPORTED] Gun dispersion

 

 

Happy Simming,

Monnie

[Lex Talionis]

..... there was never any "dispersion" designed in to the gun. It was simply the MOA accuracy due to manufacture defect tolerances.

 

Find the MOA of the gun and you will have the "dispersion" you are looking for.

[Impact]

As other planes are using the M61, the F15 might have the same problem. I found a thread concerning this: https://forums.eagle.ru/showthread.php?t=198157

[Aries144]

I thought it might be useful to post this screen capture from the video here, for reference.

 

This is a 100 round burst. The circle is 8 mil, as indicated by the narrator of the video. It is useful to note that, of the rounds missing outside the 8 mil circle, they are only barely outside it. Not spread far away.

 

[Impact]

So any update on this? Fixing this would be as easy as changing a number in a file.