Author Topic: ammunition loading and long-range ballistics  (Read 2128 times)

Offline Krusty

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« Reply #15 on: May 08, 2007, 08:55:35 AM »
Unless you can back up the assumption that out of 5 rounds only 1 would hit historically because the ballistics were so horribly off between rounds that only the one type hit, I think you're guessing here.

My guess is that the difference in ballistics at any range up to 600 yards is going to be negligable on weapons that have ranges out up to 1.2k (Hispanos) and 1k (M2 50cal). The weapon's range is far greater than that of the actual effective range. Only over greater distances will the accuracy truly start to suffer. If the dispersion is cone-shaped (like, say, rays of light from a source) and you move the target half as close, you get 4x the concentration.

I don't think the belting in hispanos was very complex. US belting was fairly simple (mostly API if I'm not mistaken). Not sure about Japanese. MG151/20 belting seems to be the most complex, with maybe the exception of MG131 belting...

Don't see how bad individual rounds would differ inside effective range, any more than the random dispersion we have now.


I admit that's just my semi-educated guess.

Offline Kweassa

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« Reply #16 on: May 08, 2007, 10:56:37 AM »
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Unless you can back up the assumption that out of 5 rounds only 1 would hit historically because the ballistics were so horribly off between rounds that only the one type hit, I think you're guessing here.


 Ask anyone who has any experience in rifles about just how much a difference in bullet trajectories can be made due to small initial differences over some 500, 600 meters - and that's only on the ground against stationary targets. Heck, even same rounds have trouble landing in the same spot despite constant conditions. That's why they call it "dispersion" in the first place.


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My guess is that the difference in ballistics at any range up to 600 yards is going to be negligable on weapons that have ranges out up to 1.2k (Hispanos) and 1k (M2 50cal).


 So you're saying different type of bullets propelled in the air will all travel at a same trajectory and only beging to dispers/drop after 600?

 Dream on.


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The weapon's range is far greater than that of the actual effective range. Only over greater distances will the accuracy truly start to suffer. If the dispersion is cone-shaped (like, say, rays of light from a source) and you move the target half as close, you get 4x the concentration.


 If we can assume an acceptable, 'realistic' firing range to be somewhere between 0~200yards, perhaps even out to 300yards in lenient views, try using .target command and see just how much a difference that 300yards can make. In planes with wing-armament, which horizontal convergence is of the greater issue the problem is pretty much evident. Even the planes with nose armament, the convergence range has to be set somewhere - and being 300 yards off the mark is more than enough to miss a plane by a large margin.

 ...and that's still not counting the difference in bullet types, since AH2 doesn't have one.


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I don't think the belting in hispanos was very complex. US belting was fairly simple (mostly API if I'm not mistaken). Not sure about Japanese. MG151/20 belting seems to be the most complex, with maybe the exception of MG131 belting...


 US belting had two~three types of ammunition. Hispano had three, Japan had two, Germany had about two~three. Two different types of ammunition already cuts down the hit rate by 50%, three types by 66%. Think about that.
 

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Don't see how bad individual rounds would differ inside effective range, any more than the random dispersion we have now.


 An 'effective range' is a range which the round stays potent enough to do actual damage. That doesn't mean the trajectory with in that range stays flat. Or rather, if the concept of 'effective range' should factor in a reasonable chance of hitting the target then the 'effective range' in aircraft guns are definately not 1.2k yards.

 Hundreds of meters is a very very long range to expect accurate hits even with a sniper gun on the ground - guess how much would flying at 500km/h at 12 thousand feet up in the air, at a target flying 600m in front of you, would be detrimental to the accuracy of your rounds fired - not to mention the fact the gun fires a different type of round everytime.

Offline Krusty

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« Reply #17 on: May 08, 2007, 11:10:13 AM »
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Originally posted by Kweassa
Two different types of ammunition already cuts down the hit rate by 50%, three types by 66%. Think about that.


See, there! Right there.... You don't know that.

The difference between an API 50cal and an AP 50cal round is minimal, and a tracer round is almost the same, but slightly different (a little lighter -- but not much).

You're making the claim that just because there are different TYPES of rounds they are so radically different that only 1 at any time will hit.


Oh, and as for sniper ranges...

In WW1 the US Marines at Belleau Wood opened fire on enemy troops from "outside" rifle range, at 300 yards, picking off dozens. It was a bloody slaughter, and the enemy thought they were inhuman devils because of their accuracy.

That's with the Mk.I eyeball and a bolt action rifle, no fancy optics. The targets were also a lot smaller than 40-foot-wide aircraft. It's all about training.

Offline hitech

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« Reply #18 on: May 08, 2007, 11:24:08 AM »
Not going to jump in other than to say, Kweassa's argument is incorrect.

The reasons why he is incorrect is

1. He first makes the assumption that the difference in ballistics will cause one bullet type to miss.

    This could or could not be the case and is completely dependent on the specifics of the case.


2. He assumes that  the the bullets of 1 type will follow the same path  and all hit at about 600 yards.

    I do not know of anyone who can land all bullets at that range

3. He assumes perfect aim, think of the case where you are aiming and all of one type are missing, now going to a mixed ammo belt will actually increase the chance of hitting, not decrease like Kweassa argues.

My point in all this, is yes at some point I would like to have mixed belts. But do not begin to believe it will have much of an effect at all in hit % or the over all out come of fights. It is really just another cool detail to put in, but the ballistic effects on hit % will be minimal if any.

Offline Kweassa

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« Reply #19 on: May 08, 2007, 01:17:50 PM »
They are mere abstractions HT.

 You can't calculate the reality, so some parameters must be equalized in order to achieve at least some kind of objective comparison, and you know this. Like you said it requires some hypothetical parameters such as "perfect aim" or "no dispersion", but what we're digging into here is just what kind of basic difference exists between different round types composed in a single ammunition belt sequence.

 Ofcourse, you'd know this math stuff a lot better than me, but even still the implications are quite clear as to just how much difference different rounds would make. This constitutes at least some kind of loose base in estimating the theoretical probability of hit rates.

 

 For example, I've consulted the following websites for info:

Quote

*Lunatic's WWII Aircraft Gun Ballistics Page
 (http://members.cox.net/rg_lunatic/gunpage/)
 :for estimated data on ballistics coefficient of WW2 guns

* WORLD WAR 2 FIGHTER ARMAMENT EFFECTIVENESS, bu A. Williams and E. Gustin
 (http://www.quarry.nildram.co.uk/WW2guneffect.htm)
 :for information on different round types, weights, and muzzle velocity

* JBM Small Arms ballistics
 (http://www.eskimo.com/~jbm/calculations/traj/traj.html)
 :for ballistics calculation tool


 
 And these are roughly the results I've got.

Conditions
* MG151/20 cannon, 20x82 cartridge
* belt composition: API,  HET,  HE(M)
* projectile weight: 117, 115, 92 gm
* muzzle velocity: 720, 720, 800 m/s
* ballistics coefficient: 0.475
* atmospheric conditions: 16.2 ¡ÆF,  29.92 in Hg, 12,000 ft
* zero range: 300m


 Now, frankly I don't have a clue as to how the ballistics calculation works. However, what I do know is that with all the rest of the parameters identical, the difference in the mere projectile weight(different ammunition) and firing velocity(use of different propellant quantities) alone is to produce the following results.


Range(m) / Drop(in)
:   API : HET : HE(Mg)[/b]
......................................
000m : -1.5 : -1.5 : -1.5
100m : +4.7 : +4.7 : +4.4
200m : +2.6 : +2.6 : +3.7
300m : -8.8  : -8.8 : -4.5
400m : -30.6 : -30.6 : -21.0
500m : -64.2 : -64.2 : -46.8
600m : -111.0: -111.0  : -83.0
700m : -172.8: -172.8  : -131.0
800m : -251.5: -251.5  : -192.3
900m : -349.6: -349.6  : -268.6
1000m : -469.6: -469.6  : -361.9



 The API and HET rounds are nearly identical, but the most potent HE(meingeshoss) rounds have a quite different trajectory coming from different weight and speed alone. Notice all three rounds are roughly equal upto 300m, but from 400m and on the difference manifests. At 600m, the difference is by 28 inches - about 2.3 feet and rapidly increasing, going over 5ft at 800.

 Some factors such as shaky aim, vibrations, dispersions and etc etc.. will no doubt play a large factor in ultimately determining the final hit rate, but looking at the base hit/miss situation alone the most potent HE round cannot connect at the same time as other AP or HET round.
 
 Like mentioned, the difference would hardly be noticeable under the '400' mark in AH2, but when the distance starts showing "600", there's definately going to be some differences.

 Ultimately, there's only one way of proving me wrong - and that would be actually observing the differences in opinion after different ammunition sequences are indeed, modelled in the game.

Offline hitech

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« Reply #20 on: May 08, 2007, 02:04:27 PM »
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Like mentioned, the difference would hardly be noticeable under the '400' mark in AH2, but when the distance starts showing "600", there's definately going to be some differences.


Yes there can be a difference but once again you imply the hit rate would be less with a mixed belt. This is the totally false assumption.

With mixed ammo (assuming different properties) we are creating more of a shot gun, at 600 yards where the odds are higher that your aim is incorrect vs being correct your odds of scoring hits will be greater with the mixed belt. I.E.

Exactly the opposit of your argument.

Offline CFYA

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« Reply #21 on: May 08, 2007, 03:52:01 PM »
Hitech is absolutly correct. For examples I will use extremes...........say all of your bullets go down the same path....ie laser.....if your aim is even slightly off you will miss. Now at say 800 yards you aim dead on with your shotgun the odds off hitting go up even tho your impacts per sq foot go down. In RL velocity variations from bulllet to bullet (same type/batch) could  amount to 5 ft at 800 yards.  I may know next to nothing about ww2 but I know a lot about ballistics. Having shot 5 inch groups at a 1000 yards as taught me a thing or two. FYI The army mandates a bullet dispersion of over 10 feet at 1000 yards on a belt fed 50 cal.
Ryan

Offline titanic3

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« Reply #22 on: May 09, 2007, 06:16:33 PM »
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Originally posted by Blooz
I feel AH2 guns have half as much probability of hitting the target than actual rounds in real life.

Why?

Most of us that play aren't trained combat pilots and we aren't in a situation that is a life and death struggle.

Why not ask for something simpler like gun jamming or wind?

Something as insignificant as the difference in tracer round trajectory would be alot of work just to make kids who are pretending to be fighter pilots miss more than they already do.


technically, we don't miss 'cuz we're in the 21st century, all we do is track, lock, identify, and press the big RED button.

  the game is concentrated on combat, not on shaking the screen.

semp

Offline Blooz

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« Reply #23 on: May 09, 2007, 07:59:30 PM »
We do miss.

We miss alot.

It's programmed into the game.

What I'm saying is between the programmed dispersion of rounds and the untrained nature of our 'pilots' we don't need to model the minor differences between tracer rounds and normal rounds.
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Offline Stoney74

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« Reply #24 on: May 09, 2007, 08:10:32 PM »
Blooz,

I think Kweassa is trying to determine why people have the uncanny ability to get kills at ranges longer than those that were effective historically.  Almost everyone will "try" a shot at 1.0K just to see if they can nick the LA-7 enough to slow it down and catch it, for example.  In real life, very few shots of this nature were ever attempted, as most pilots "knew" they wouldn't be able to hit effectively beyond 300 meters or so.

I think he's just trying to get a more realistic (from a historical perspective) representation from gunnery in the game.  Personally, I think its bull stink that someone can hit me with a Mk108 from 800 meters, and therefore encourage any discussion of this sort.

:aok

Offline Blooz

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« Reply #25 on: May 09, 2007, 09:12:53 PM »
Looks to me as if he's advocating the introduction of ammo rounds that have slightly different trajectories.

All I'm saying is that we don't need it. The dispersion pattern now is twice as much or more than what you'd have in real life and that should be enough to simulate differing ammo types.

As for the reason for uncanny accuracy? Same as collision modelling. What you see on your computer and what the other guy sees are two different things.

If you see someone at 800 shooting at you it's quite probable that he's actually closer due to the time it takes the data to get to the server and back to your computer. It may look like 200 or 400 to him and looks like 800 to 1K to you. It's just the nature of the internet.
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Offline Stoney74

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« Reply #26 on: May 10, 2007, 12:43:07 AM »
Quote
Originally posted by Blooz
All I'm saying is that we don't need it. The dispersion pattern now is twice as much or more than what you'd have in real life and that should be enough to simulate differing ammo types...It may look like 200 or 400 to him and looks like 800 to 1K to you. It's just the nature of the internet.


I agree with you about the different ammunition, but I agree with Kweeasa about the uncanny ability to hit at long range.

I've verified being hit at 800 meters through the film viewer.  I've also checked my distances with squaddies flying close formation, and I'm typically 15 meters further away from them than what I see.  Don't know how scientific either of those two are, but it's all I've got to go on.

From my tests offline, a Mk108 (Bf-110 mounted) with convergence set at 650 on a target at 650 yards has a pattern that appears to contain approx. 75% or more of the rounds within 6 mils (or 3 mils left or right).  The 75% is a guess from looking at the pattern on the target.  That's a pretty tight group for a gun that wasn't supposed to be effective much beyond 200 meters.  Of course, it could have been that since you couldn't change the convergence of the Mk108 in real life, the factory had it BZO'd at 200 meters.  Who knows?

Just think its interesting that the real life guys rarely shot beyond about 300 meters, but here, you can safely go much further out with a high expectation of accuracy.  What I'm most curious about is why the discrepancy.  And, even though I may be putting words in his mouth, I believe Kweeasa is looking for "why" as well, even though he initiated the thread with a discussion of different round-type ballistics.

Offline Knegel

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« Reply #27 on: May 10, 2007, 03:07:20 AM »
Hi,

i dont know why it shouldnt be possible to hit a strait flying target on 800yard. The US 20mm cannon got valued with a max proctical range of 1200yard, while it had a max theoretical range of 2400yard.
The early .50cal had a max practical range of 300yard and a max theoretical range of 900yard.

I dont know how often you got shot down by .50cals on 800yard, but i guess this only did happen with unlimited ammo or while you was in a stallturn and did present the large side of your plane and of course a almost still standing plane is a rather easy target.

I rarely got shot down on 800yard with MG´s, in general i only fear the wing mounted Hispannos and the 3 x 20mm of the La7 on this distance.

btw. while creating a new DM for EAW i found that on long range a higher dispersion often lead to a better hitquote(unwanted of course).
This is so, cause the bullets seems to be much to big, and so they cover a much more big area, in combination with a dispersion you simply cant fail.
I did counter this by setting the dispersion to almost zero, as result the player need to aim VERY exact to hit the target, but this is rather difficult.  In game this result in much more difficult long distance kills.

Of course i dont know how AH work regarding, just a thought.


Greetings,

Knegel

Offline Charge

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« Reply #28 on: May 10, 2007, 06:53:32 AM »
"That's a pretty tight group for a gun that wasn't supposed to be effective much beyond 200 meters."

Those two things have nothing to do with each other.

The low velocity (recoil) and low ROF along with one type ammunition and nose mounting resulted in low dispersion for that particular weapon set.

The practical range was low because of low velocity and thus at long range you do not shoot at the profile of the plane from the rear but in a way you have to "drop" the projectile on the target and in that scenario even a slight change in closure rate makes the aiming very very difficult. At 200 yds you can shoot the target without considering the projectile drop of without suffering from the rapid drop at longer ranges. And I can assure that the 30mm Minen grenade is as lethal at 200 yds as it is in 800 yds or even at 1200 yds...

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Offline Kweassa

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« Reply #29 on: May 11, 2007, 05:38:42 AM »
Was waiting for a bit if Tony can bump in and clarify a few things, but perhaps he's busy for the time being.

 The chance of hit does not directly increase in proportion to dispersion. If that is to be made true it would require another batch of those abstract conditions, such as "dispersion increases the chance of hit in proportion to the amount of rounds fired". Frankly, accounting the dispersion factor as a means to hit an aerial target takes for granted that the process of "reasonable aiming" is non-existant in the first place, and therefore the shooter is to rely on a more a less semi-random patterned dispersion to hit anything.

 In other words, it is a "fire enough rounds in the general direction and hope at least some of those rounds hit" approach. The entire concept of "aim" is neglected in that kind of thinking.

(Frankly, this is the part where the "get rid of the ammo counters" and "get rid of distance indicators inside 1.0" argument justifies itself, since it requires somewhat hefty volume of rounds to be propelled in the air, so a round that is destined to fly inside the general dispersion pattern eventually finds a way in a random chance.

 If the ammo counters are removed, and people do not have the means to keep track of remaining rounds, every attempt in long-range gunnery increases the anxiety factor to the pilot, until it eventually pressures him to stop firing at such distances in the first place - in which case the chance to hit at long ranges eventually reaches near zero levels, since if the pilot does not shoot, that 'chance' influenced by the dispersion becomes meaningless.

 I was preparing a number of 'challenges', with some amount of confidence, for those who claim they don't have any problems in judging distances even without the 200yd incremental 'markers', until my Photoshop crashed on me, so it might take a few more days until it is prepared again.)

 The very process of aiming presumes that by 'aiming', a reasonable chance can be expected to hit the target with reliable accuracy. Therefore, the 'aiming process' is meaningful when the distance is close enough for the human pilot to accurately judge and aim, and then finally pull that trigger to expect a certain amount of hitting accuracy ratio in relation to the total number of rounds fired.

 However, saying that 'dispersion increases the chance to hit" is dangerously misleading IMO, in that such assumption leaves out a single word - which would be "eventually".


 Imagine a situation where you have a limited amount of rounds to fire against a plane's 6 o'c angle. At a distance of 100~200yards, when you have limited 100 rounds to fire, the hitting accuracy can be deadly high.

 However, imagine the same target at 600yards, and you fire that same 100 rounds against it. How many here thinks that when the parameters are set identical, only 100 rounds to be fired, that you will still achieve a higher rate of hit because of dispersion?? Only when you fire, 100, 200, 300, 400 more rounds, will the dispersion finally allow some of the fired rounds to connect at the target. Dispersion doesn't allow a higher hit rate at the same parameters - it only allows it at the price of wasting very many rounds to finally achieve a satisfactory number of hits - I don't call that 'higher hit probability'. I call that 'higher hit probability simply due to more numerous attempts".

 What we're talking about here is the hit probability that can be attained and influenced by human aim. When I am talking about "long-range hits", I'm not talking about those fluke shots which rarely happens in the game. I'm talking about the people who can aim at a target flying at least some 500~600yards in front of him, and then constantly achieve a meaningful probability to seriously damage, or even shoot down the target in only the first or second burst fired from his plane. Perhaps Stoney's case of being on the receiving end of those MK108s at 600 yards out, could be one of these cases.

 Clearly, those people have a correct aim, and do not rely on the pure chance factor of the dispersion pattern to hit the target - they actively aim, and aim accurately despite very far distances and while I do admit at least some 60~70% of their "good aim" is due to experience and skill, at least some 30~40% of the secret to their success is caused by some parameters from the game that existed in real life, but do not exist in the game, which (this is the catch) can be introduced into the game without causing too many problems.

 Some people say that is caused by the different FEs, but I distinctly remember Wotan/Batz/Bruno's experients which proved that actual difference in the FE rarely, if ever, extends further out than 100~200 yards. I only wish Bruno was here to clear the point.

 But I digress.

 In the above mentioned cases of people who regularly achieve a reasonably high chance of shooting down planes at such distances, I suspect the entire process is influenced by specifically the ammo counters, distance indicators, and the identical ammunition fired. I imagine what they are doing is;


1) see the plane, judge the relative E factors, and then make a 'guess' as to just where the plane is when it indicates "600".

2) Relying on that visible, verifable "600" number, they place the target plane at a certain position on the gunsight, giving a vertical lead as they are trained to by using the "600" verification.

3) This aim may not be as accurate as closer distances, but it is enough to place the target smack in the middle of the dispersion pattern, where the bullets are most grouped.


 Therefore:

1) by removing the "600", the 200yd incremental distance indicator from the icon, we first remove the very basic judgement tool which more or less verifies a certain range of the target, that the pilots can rely on, and move the entire "judge distances" to the realm of uncertainty, as it should be.

2) then we remove the ammo counters, and move the "calculated risks concerning spending available ammunition", again, into the realm of uncertainty. Perhaps in his first, second, or even third engagements the pilot would pretty much not hesitate to "spray" some of his rounds at long distances, expecting a hit, but I can bet that when it comes to his 4th, 5th, or more engagements he would be ever more uncertain about the condition of his available ammunition - which, will ultimately discourage him from even attempting a long distance shot.

3) and then, by introducing different ammunitions, we not only diverge the "quality" of his hit at long distances (in case of cannons, some of his hits achieved might not be the powerful HE rounds, but rather the more weaker AP rounds), but we also influence the dispersion itself. A pilot, with experience, may be able to lead the target so it rests at the most concentrated, center location of the circular dispersion pattern - but at least more than half of his rounds (that have different ballistics), will fall lower from that most concentrated place.


 
 In the end, I do not believe long-distance gunnery is achieved by skill alone. I think it is also achieved by a significant amount of unvoluntary 'exploitation' of the system (if you can call it 'exploit' in the first place) - which, IMO, can be corrected. AH was always forthcoming when it came to "situationary realism" as opposed to "technical realism" and that is one of AH's great points IMO. I don't see why my suggestion cannot be valid, as it is not as if I am requesting for an artificial "bullet inhibitor" that prevents hits at long ranges.

 All I am asking is that AH be a little bit, just a tad bit more life-like, and let's all see where that leads to.


I mean, in the worst case scenario, I could be totally wrong and people would still be achieving 600yd hits regularly - no harm done to any of you out there, since the game stays the exactly same.

 In the best case scenario, the gunnery distance would be shortened, and people will have a lot more hear-pumping dogfights at close-ranges.


 Nothing to lose, only lots to gain - what can be more better than this?