[FIXED] M-61 Vulcan and Gau-8 Avenger dispersion values

Ok, and ontop of that what do the values in the shell_table.lua mean (DA0) mean exactly.

Well, it does seem like the values are pretty close, I guess it is settled for the GAU-8.

Wasn't that hard now was it ?

Ok, and ontop of that what do the values in the shell_table.lua mean (DA0) mean exactly.

This is really the important question since that's pretty much where the whole thing started, and it really has never been addressed, much less answered.

On the one hand, we have a set of weapons that have values that clearly correspond to specific published test-bench figures, and these values are supposedly accurate for the weapon in question. On the other hand, we have a weapon that have values that are nowhere near any published test-bench figures, and these values are supposedly also accurate.

So which one is it? The only way for both to be accurate is if each weapon is coded so wildly differently that the shell table values are essentially meaningless. Otherwise, one of the two simply must be wrong: the values that correspond to published data, or the values that don't.

This is really the important question since that's pretty much where the whole thing started, and it really has never been addressed, much less answered.

 

On the one hand, we have a set of weapons that have values that clearly correspond to specific published test-bench figures, and these values are supposedly accurate for the weapon in question. On the other hand, we have a weapon that have values that are nowhere near any published test-bench figures, and these values are supposedly also accurate.

 

So which one is it? The only way for both to be accurate is if each weapon is coded so wildly differently that the shell table values are essentially meaningless. Otherwise, one of the two simply must be wrong: the values that correspond to published data, or the values that don't.

Agreed, the GSH23, 30-1, and BMP gun (forgot the name) all have values in the lua file that seem to be accurate. .0005,.0007, .0004 respectively. Yet the Gau8 and Vulcan with similar dispersion values to the first two Russian guns respectively are .0022 and .0017 many times the values used for the Russian guns stated to have similar dispersion values irl.

Ok so i've done in game tests at a 1000 inches to allow comparison with the project vulcan documentation I showed in my first post. Hopefully this can be the new standard for all testing in this regard as it is what is most often used in testing. I set up an F18 at 1000" (83.333 ft) with active pause on then fired at the target (same as in my last analysis post). After this using tacview I extracted the initial and final positions of each bullet. Each test was done with 100 rounds. I ran this test twice with the third time using the value of .0008 for the dispersion. Units for the graphs below are inches. Additionally I then used the data to figure out what the 80% and 100% circles where for each grouping.

Vanilla results:

Spread:

Green = 80% within 10.04mills

100% within 25.78mills

Red = 80% within 9.45mills

100% within 22.86mills

Orange = 80% within 4.27mills

100% within 10.18mills

When all of them are overlayed together along with dispersion pattern 11 you get:

Any chance of ED responding again to this thread? I've provided the evidence to support the dispersion is way to high in multiple posts through this thread.

It is also probably too high on Phalanx, which are tuned to the order of 2-3 mils as they require high concentration of rounds at distance.

Actually less, I found documents stating that it should be just under to just over 1mill. I don't have it on hand right now but when I can get it I can send it to you if you want.

We're probably talking about the same document :)

Probably, and considering that it appears the results of that study were taking into account and additional bracing as added to the phalanx I think it's safe to assume that the results of the study right under 1 mill average is probably what it is even up to today.

An additional point that I want to make (and it seems that keeps getting ignored) is that the 2A42 gun is noted to have somewhere between 3-4 mills of dispersion for its 100% (at least that's what I remember it may be the 80%) circle. And in the code it's set as .0004. Yet the Vulcan for both ships and aircraft is at .0022... Which is 550% higher instead of the 225-245% (~9-10mills for 100% on the Vulcan) indicated by literature and proven by the various videos out there.

Care to comment, ED? Most recent study here by Nighthawk seems pretty darn conclusive...

Fine on the GAU-8, but we've also got the M-61 along with plenty of documentation which has been already presented to ED.

And moreover, there are different tunings for different applications (eg. aircraft vs CIWS).

Naw, that was already addressed by Yo-Yo as well ..

 

https://forums.eagle.ru/showthread.php?t=242921

Well, the fact is though his one post where he actually said something and didn't just ask questions or just said 'wrong' were dismantled...

"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."

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These clamps don't exist in an operational sense. They were experimentally tested once back in the very early 60's as per one project Vulcan report but were not developed further let alone actually used. (also they weren't even clamps but they used a different muzzle to achieve the affect sooo) In particular, for the 20mm this is all i've ever found. After hours of research and even talking to Habu different clamps for the avenger we have 0 proof they A) exists or B) were even used.

 

As the ratio is close to 8, any military can say that it is MEDIAN

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???? The dimensions of the circle are quite clearly given so this makes no sense.

 

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.

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Finally yes the wider dispersion may be of some advantage in certain situations but not for A/G.

 

And moreover, there are different tunings for different applications (eg. aircraft vs CIWS).

 

can we at least get a different dispersion value for CIWS to make it more effective?

Admittedly CIWS needs guidance and burst improvement ... the dispersion helps destroy things at longer ranges, but guidance and correct burst fire is required to make that work anyway.

For now but hopefully, we can show that it needs to change because how it is right now is not accurate and in the case of CIWS detrimental to its effectiveness.

And even then as I hope i've clearly shown that the values don't even get close to the values listed everywhere:

https://forums.eagle.ru/showpost.php?p=4106908&postcount=80

Only just came across this thread - I might add some input. As a f-18 A/B armament fitter I have pulled the m61a1 apart and back together a dozens of times. I also worked at the Aussie bombing range (Saltash) and used to report the shots seen by the acoustic scoring system for the gunnery lanes - the shots go all over the place. There are so many factors involved, the gun is above the radar package and there was much development work on the hornet to ensure that vibration was not effecting the radar excessively. When the gun fires hydraulically you have ballistic gases coming out of the two holes in the blast defuser and engine bleed air going into the gun bay to purge all the gases via the scavange door (thats the loud sound you hear when the gun fires) - all this is happening at 6,000 shot per minute at high rate and with the tolerances on the driving bands on 20mm ammunition you can see that dispersion in real life on the ground. Even when the gun has a high speed stoppage you can physically see the aircraft roll. Further different aircraft were more accurate and tighter dispersion than others.

Nighthawk - I enjoyed reading your posts and views, that said as an actual F-18 armourer who used to observe the shots, DCS has it ok. There may be something else to look at to help ED out with.

Again only my view from working on the jolly thing............

Gunnie - sorry about my poor spelling.

Only just came across this thread - I might add some input. As a f-18 A/B armament fitter I have pulled the m61a1 apart and back together a dozens of times. I also worked at the Aussie bombing range (Saltash) and used to report the shots seen by the acoustic scoring system for the gunnery lanes - the shots go all over the place. There are so many factors involved, the gun is above the radar package and there was much development work on the hornet to ensure that vibration was not effecting the radar excessively. When the gun fires hydraulically you have ballistic gases coming out of the two holes in the blast defuser and engine bleed air going into the gun bay to purge all the gases via the scavange door (thats the loud sound you hear when the gun fires) - all this is happening at 6,000 shot per minute at high rate and with the tolerances on the driving bands on 20mm ammunition you can see that dispersion in real life on the ground. Even when the gun has a high speed stoppage you can physically see the aircraft roll. Further different aircraft were more accurate and tighter dispersion than others.

 

Nighthawk - I enjoyed reading your posts and views, that said as an actual F-18 armourer who used to observe the shots, DCS has it ok. There may be something else to look at to help ED out with.

 

Again only my view from working on the jolly thing............

 

Gunnie - sorry about my poor spelling.

Thanks for the input but this still doesn't change my opinion. We have not only strafing run footage, and piolts agreeing with dispersion being to high, but documentation. And now recently the test I performed all point to one thing and that is the dispersion in DCS is way too high (in particular for CIWS). I'm not saying the gun has 0 dispersion but significantly less than what it is right now. And I just can't come to any other conclusion based on all the evidence shown in this thread. The view that DCS's dispersion is correct I view as illogical in the face of all the previous evidence posted.

Hey dude - thanks for the reply.

Is there anything I can produce at my end that may give you a visual picture of whats happening on the ground (bombing range stuff) let me know. I am also more than happy to discuss uneven barrel wear with you (clearing sector and firing sector)

I think that the thread has got confusing, you have 20 mm and 30 mm systems mixed together (different ballistics) and comments about A-10 pilots and Tornado pilots (that one has me really confused - they have canon). You also have CIWS into the mix - perhaps you need to separate the subjects out? - not you fault just where things have ended up.

Not once have I read about range / convergence points, unlike what has been stated - yes they do have barrel clamps and yes they do help - there is a torque specification and that is lock wired.

Mate respect you have formed a world view on this and respect all the trouble you have gone to but can you consider what F-18 pilots and armourers can report to you as facts. If there is any additional information I can provide (non classified) just let me know as obviously you are really interested and I would like to help.

I hope you take this post in the best spirit that I intend it to be. There may even be many armament questions you may want to ask that I may be able to help with - cheers mate.

Gunnie

Is there anything I can produce at my end that may give you a visual picture of whats happening on the ground (bombing range stuff) let me know. I am also more than happy to discuss uneven barrel wear with you (clearing sector and firing sector)

Not sure what you have so it's hard to say. If you happen to have hud tapes where we see the impacts that'd probably be the best.

I think that the thread has got confusing, you have 20 mm and 30 mm systems mixed together (different ballistics)

Not really, yes they're different in size but the forces that cause dispersion are fundamentally the same. And I think this is best shown by the fact they have very similar dispersion values. Around 5mills for the 80% circle for both between 10 and 13 mills for the 100% circle for the two.

and comments about A-10 pilots and Tornado pilots (that one has me really confused - they have canon).

As far as I'm aware there is one tornado variant with a Vulcan if I'm wrong then please do correct me.

You also have CIWS into the mix - perhaps you need to separate the subjects out? - not you fault just where things have ended up.

Not really, all of these guns have way to much dispersion and in particular, the CIWS which is mounted in such a way to have 1mill or less of dispersion.

Not once have I read about range / convergence points, unlike what has been stated - yes they do have barrel clamps and yes they do help - there is a torque specification and that is lock wired.

Yes they have barrel clamps but specific clamps to produce a shotgun like dispersion pattern haven't been used operationally on aircraft. I've really only seen one report on this and it was back from the early 60's as a test. And from these tests it was quite clear to produce specific patterns the clamp/muzzle device had to be shapped in quite a unique way.

Mate respect you have formed a world view on this and respect all the trouble you have gone to but can you consider what F-18 pilots and armourers can report to you as facts. If there is any additional information I can provide (non classified) just let me know as obviously you are really interested and I would like to help.

All the facts that my view is based on is present in this thread.

No Tornado carries the Vulcan, they all use the Mauser BK-27 revolver gun that is also carried by the Typhoon and Gripen. The only European-built jet that I'm aware of that uses the Vulcan and flies in the same role as the Tornado, is the AMX.

The only European-built jet that I'm aware of that uses the Vulcan ..., is the AMX.

And the Swiss F-18C. Designed by americans, built by swiss. (Little side note)

I don't follow what hud tapes will tell you - what I am talking about is what the scoring system see's and report back to the pilots. As stated barrel wear can be very uneven due to the nature of operation of the gun (this is a fact) All I am saying is what DSC has matches what is seen in real life (I have seen it myself as it was my job). You can't base comments on DCS having it wrong based on a 1962 document on a gun bolted firmly to a table - it is not like that in the hornet - i.e. the real world.

Wags even posted that he raised this question to A-10 pilots and they stated it was correct, the F-18 pilot they referred to question to said it was correct and I am trying to help you to understand why it been implemented in DCS as I was a guy who actually repaired the hornet gun and worked at a bombing range that recorded dispersion using acoustic ears that detected the shock waves of the rounds.

I wish you luck but I don't think you are going to get too much further on this one.

Gunnie