Russian guns balistics...

[Holtzauge]

I am not sure that SuperEtendard has concluded the first point correctly yet - it first has to be established that the axis of the aircraft is not moving in the flight tests.

 

Re vertical vs horizontal dispersion -  I am not saying horizontal dispersion does not matter.  Firstly, I was differentiating between dispersion - the group size at a given range, which includes the horizontal and vertical variance since I assume the group variance is circular - versus the trajectory which is the vertical position of the entire group over range, in which I assume there is no variance for a given shell type.  The second matters much more because you have to know two facts - range and trajectory - to compute the required elevation.  In contrast, irrespective of the group size, placing the pipper on the target's vertical line is always correct - in the case of the zero deflection shot the test is discussing. 

 

You say that the chance of a hit is less with a larger group. That is obviously true only in the case when the pipper is at exactly the right elevation and vertical line. People actually shooting will have an aiming error around the ideal position, and some shots that could not possibly hit with the optimum pipper position will score hits with a larger spread. We are back to the question of what should be the optimum spread for a shotgun cartridge.  In terms of what spread will give the maximum number of occasions on which at least one hit is scored, or the maximum number of hits over a sample of bursts, I am not convinced that the tightest possible spread is optimum at all.  But that can only be established if in addition to the gun data we have measured the actual aiming errors people make.  

 

The optimum group also depends on whether you are prioritizing frequent single hits, or rarer multiple hits. Given that the 109s allegedly fall apart after a single hit, it is not obvious that a very tight group for the ShVAK is an advantage at all in this sort of shot: although a too flat trajectory certainly would be, no argument there.   

 

I agree that if things can be identified as wrong they should be corrected - the problem is being sure what is wrong when in game testing is so tricky and the results are compared with historical documents that were not all compiled on the same basis.

 

Well since the shotgun example is back again I will again say I think that analogy is flawed: First of all shotgun hunting is instinctive and aiming is done with the barrel tip relying on that the cheek is in the right place. In addition, you don’t lead the target but “swing” into the shot. So both the means of aiming and the “aiming” process is totally different from the 800 m sniping shots. In addition, the shot has to take place within seconds and while there may be a second chance there is (usually) no tracer feedback to tell you which way to adjust. So, the solution is to shoot all you have in one go relying on the “spray and pray” principle.

 

The discussion in this thread has been about sniping and while you said before you don’t agree with the parallel to IRL rifle sniping I’ll explain a bit more in detail why this IMHO is a more valid analogy: In both cases (air and ground sniping) you have quality optics that allow precision aiming. In both cases you have time to do the aiming (Remember this is about an extending aircraft at 800 m feeling safe, no jinxing). The relative velocity in x,y and z directions is small. Now this is exactly the sniper problem shooting a moving target. In fact it’s even more difficult since there is wind involved. No matter: the sniper makes a judgement on range, target speed in horizontal and vertical plane and fires. Now usually that is the only chance you get but sometimes the target is clueless and you can watch either the tracer (air case) or the spotter calls the shot. Based on this you correct and fire again. This also covers the mistake in range you bring up: it is better to watch the fall of shot and correct the height error than spray and pray with a larger dispersion.

 

Now if your weapon spreads as much as a man’s heights or a target wingspan in mils you will be clueless if it is your aim or the weapon spread causing you to miss. So to conclude, for long range sniper shots both on the ground and in the air a low spread is good and any sniper will tell you so. So IMHO, if your weapon spread at 800 m with cannon A  covers a circle with the wingspan as diameter you are in a worse position than if you have cannon B which covers only half of that or putting it another way, only ¼ of the area, e.g 4 mils versus 2 mils.

 

Regarding the possibility that the autopilot is worse controlling German planes than Russian: I never saw any difference in my tests and think that can be struck as the explanation based on JtD’s groundtest of MG151/20 and ShVAK but If you still think that’s a significant contributor I think you should try to compile some evidence to support your theory.

 

That leaves the data we have so far which as I see it seems to indicate that both the ShVAK and MG151/20 have around 1.8-1.9 mils spread inherent uninstalled and that when MG151/20 is installed, it in IRL has 3 mils dispersion with engine running when bursts are fired and that in-game it is larger. The ShVAK OTOH has been implemented in-game with a spread that mirrors an IRL test for single shot no engine running. So as I see it, with the evidence we have before us to date, the MG151/20 is pessimistically implemented (at >3 mils) while the ShVAK very much optimistically implemented at around 1.8 mils.

[JG13_opcode]

Good lord, are people really arguing that more dispersion is good?

 

We're not shooting magical tank-flipping 50 cals of myth and legend. We're shooting 20mm HE shells that, individually, have very little effect. You want a higher impact density to maximize rounds on target, not a lower one where you need to pray to the gods of ballistics that you get a lucky strike.

[unreasonable]

What I am saying is that the optimum dispersion to get a particular kind of result is an empirical fact, not one that can be deduced from theoretical musings. This is because the optimum results can (1) be defined in different ways depending on what you are trying to maximize, and (2) are dependent on the aiming error as well as the group dispersion.

 

It is a fact that many automatic weapons are designed to produce a specific size group - not necessarily the minimum that is possible - for precisely these reasons.  In principle I see the weapons under discussions no differently, so when people assert - with absolutely no empirical evidence but only analogies from single shot sniping - that the smaller group size of the ShVAK  is a factor worsening the so called "sniping problem" in game I bring up this topic. 

 

As to the data for the group size in game or in documents, I have nothing to add except that Holtzauge's conclusionmay well be correct when he says "That leaves the data we have so far which as I see it seems to indicate that both the ShVAK and MG151/20 have around 1.8-1.9 mils spread inherent uninstalled and that when MG151/20 is installed, it in IRL has 3 mils dispersion with engine running when bursts are fired and that in-game it is larger. The ShVAK OTOH has been implemented in-game with a spread that mirrors an IRL test for single shot no engine running. So as I see it, with the evidence we have before us to date, the MG151/20 is pessimistically implemented (at >3 mils) while the ShVAK very much optimistically implemented at around 1.8 mils."

 

I would not be surprised, however, if these figures are changed to make them more or less equal, the MP sniping complaints will be absolutely unchanged.  My bet is that making the ShVAK trajectory less flat would have a much larger effect on outcomes.  Either way,  no need for anyone to get defensive about it - it is the developers that have to be convinced that there is a mistake, not me.

[Irgendjemand]

Yet again thanks to the usual suspects for spending their time doing research on the matter!
Anyone filing a report ot the devs?

[Holtzauge]

Yet again thanks to the usual suspects for spending their time doing research on the matter!

Anyone filing a report ot the devs?

 

Not that I know of and maybe it would be good to also come to a conclusion about the ShVAK muzzle velocity and trajectory questions: Right now it looks like we have a number of different muzzle velocities, bullet weights and drag numbers which affect how flat shooting the ShVAK should be so maybe it would be good to get to the bottom of that as well before submitting a report?

 

Edit: The same goes for the MG151/20 as well of course!

Edited September 27, 2017 by Holtzauge

[JtD]

Point is we have a source that gives the figures the developers are using. We would need a 'better' source if we were to make a point. I find the German test results much more reasonable than the figures from the Soviet manual, but on that basis it would not be possible to convince anyone. In particular if the devs can expect a mild sh*tstorm if they inform the community that they've based their new ballistics on a couple of figures from a German report and some common sense. There's no reason for them to change anything, and certainly no reason to make the effort.

 

Slightly different story about the dispersion, we have Soviet figures for the ShVAK noted to be single shot, which appear to be met in game. We have German figures for 11 shot bursts, which appear to be exceeded in game. We could make the point for lower dispersion for the MG151, but IMHO the far bigger issue is the muzzle velocity and the speed retention of the ShVAK rounds.

 

So right now, we still need good Soviet test data for the ShVAK, with particularities such as round type used, plus details about what's supposed to be modelled in game.

[ZachariasX]

... We're shooting 20mm HE shells that, individually, have very little effect. ....

It seems you never fired one of those. Depending what they hit, I can tell you they can do considerable damage.

 

Then again, I do agree with the point you‘re making.

Edited September 27, 2017 by ZachariasX

[ZachariasX]

...It is a fact that many automatic weapons are designed to produce a specific size group - not necessarily the minimum that is possible - for precisely these reasons. ....

Size group was obtained by individual arrangement of the individual guns. If it is not a shotgun, dispersion is nothing but bad. For instance (Spitfire as well as others) pilots could choose in their lanes wether the weapons would be aligned for point precision or maximum (resonable) dispersion at shooting distance. Rookies got more dispersion as shooting on the average was tagically bad. So maybe the gun might hit something if the pilot aimed in the wrong place as usual. As soon as someone got confident in his marksmaship, he would set the guns to point target. Results were more than worth it.

 

The „good old“ Oerlikon 35 mm Flak was said to be precsise enough to shoot in the same hole made by the previous bullet. The old versions with their knee joint action the had the appaling fire rate of the pom-poms though.

[JG13_opcode]

It seems you never fired one of those. Depending what they hit, I can tell you they can do considerable damage.

 

Then again, I do agree with the point you‘re making.

I don't mean a real 20mm.

 

The in-game 151/20 does not seem adequately effective to me, but perhaps I'm just used to other sims. I'd much rather have a ShVAK in game. Lighting 109s on fire or taking wings off feels effortless compared to the reverse.

 

A single 20mm from the 109 is rarely enough to cause anywhere close to crippling damage.

Edited September 27, 2017 by JG13_opcode

[unreasonable]

Size group was obtained by individual arrangement of the individual guns. If it is not a shotgun, dispersion is nothing but bad. For instance (Spitfire as well as others) pilots could choose in their lanes wether the weapons would be aligned for point precision or maximum (resonable) dispersion at shooting distance. Rookies got more dispersion as shooting on the average was tagically bad. So maybe the gun might hit something if the pilot aimed in the wrong place as usual. As soon as someone got confident in his marksmaship, he would set the guns to point target. Results were more than worth it.

 

The „good old“ Oerlikon 35 mm Flak was said to be precsise enough to shoot in the same hole made by the previous bullet. The old versions with their knee joint action the had the appaling fire rate of the pom-poms though.

 

That is a different issue - you are talking here about the the harmonization of multiple guns, not the group size of an individual gun.  As your last comment in fact demonstrates, the minimum possible group size is not necessarily optimum - why would you want all the bullets but the first to pass through a hole in the target?

[-=PHX=-SuperEtendard]

I think that having little dispersion can be detrimental in some cases, because it's most likely you are not going to guess the correct target's distance at these long range shots, with the static gunsights we have for the German and Russian planes. If you have 0 dispersion then by misjudging the vertical lead you are just going to miss, even if that mistake is small.

 

You want to have enough dispersion so that you can get an acceptable probability of hitting the target if you have a bit of error in guessing the lead, but not so much that if you get it right then you miss most of the rounds fired anyway. The case in which I fully agree little dispersion is the most desirable is if you have a gunsight which can calculate the lead to the target if you know it's range (which you can find out by adjusting the control until the target fills the sight knowing it's wingspan).

 

The MG 151 15mm has some dispersion, similar to the MG 151/20 I think, yet a much flatter trajectory and imho it's not that much different in long range shooting to the Soviet 20mm. Imho little ballistic drop > dispersion in this long range sniping bursts.

 

 

About the auto drift rudder wobble, yep I noticed it as well, it's a very slight rudder movement. I guess the test with a straight flying plane ahead is a good idea to see if it has a meaningful impact in moving the nose bearing.

[ZachariasX]

That is a different issue - you are talking here about the the harmonization of multiple guns, not the group size of an individual gun. As your last comment in fact demonstrates, the minimum possible group size is not necessarily optimum - why would you want all the bullets but the first to pass through a hole in the target?

 

If you can do that, then this is your fast track to 4 Star General. And as an alcoholic, as you would be awarded a bottle of Champagne each time you do that.

 

 

I think that having little dispersion can be detrimental in some cases, because it's most likely you are not going to guess the correct target's distance at these long range shots, with the static gunsights we have for the German and Russian planes.

 

Again, for longer range guns (not for the shotgun or the Uzi, they are a whole different sport), dispersion is nothing but bad. It is so bad that you even carry a lot of spare barrels for your autocannons and especially for your machine guns. If you are fond of dispersion, just keep the same worn barrel. Result is, you will not hit anything. At all.

 

Now, what does dispersion to you? Example: With a ten shot burst and having for instance a 10 meter circle dispersion at your average shooting distance, it means that you will randomly place 10 shots in one second time in this circle of dispersion. Say, you track the airplane (with this dispersion circle going from wingtip to wingtip and at a good angle so that the airplane covers say 10% of the area of your dispersion) with perfect aim, you can expect to land 1 hit somewhere on the aircraft. With ideally no dispersion, you have 10 hits in one second, or alternatively 1 hit in 0.1 second exactly where you want. Notice also the time difference. Landing 1 hit somewhere with the 10 meter dispersion requires perfect tracking of your quarry over 1 second time. You don't do that, your hit expectancy drops below 1 witch means in practise, you don't hit at all. It totally eliminates the possibility of a snapshot. It may be counterintuitive, but it is a fact.

 

When pilots got their guns set for dispersion, one has to keep in mind that this kind of pilot parked behind their quarry and just hosed it down until it disintegrated, left the Revi for some other reason, or the ammo was gone. These were not the type of pilots that could expect to land a hit with lead shooting. Peeps in IL2 here have a great lot of target practice. Far, far more than combat pilots back then. That does not compare.

 

If you are in the business of just hosing down your quarry, even then dispersion is bad. I will take the example of a garden hose. Do you feel it is easier to hit a plant when you set the spray to a straight flow or when you break the flow open? The answer is clear. As you are tracking your flow of water (or the tracers in cannons) you just walk your spray on the target and you get 100% hit and not a frustrating 10% hit even with exact aim. (I took this example just  for illustration, unreasonable being English is for sure the better gardener than I am, so ask him about gardening practice. )

 

That some pilots still got set their guns for dispersion just shows how abysmal the average shooting abilities were. Pierre Clostermann commented on that in the newly published “Le Grand Cirque 2000”, the completed version of his famous book “The Big Show” that features also the omitted pages (paper shortage after the war) plus comments of his about the events described.

 

To sum up: If you are in the business of shooting, then dispersion is ok. If you are in the business of hitting, then dispersion is your enemy.

 

It also matters a lot if you measure individual shots or bursts, as Holtzauge mentioned above. Ideally, we would need scatter from all guns taken under similar conditions. Otherwise, the scatter is largely dependent on the state of your barrel and that one can be significant, WAY more than the subtleties we are experiencing with the German/Russian guns. We can also say that in the game we are lucky to always have factory fresh machine guns/cannons.

Edited September 28, 2017 by ZachariasX

[unreasonable]

Unfortunately I am one of those rare Englishmen at whose approach plants wither and die.  

 

I still take issue with your assertion that you can adjust the aim like a garden hose. The problem with shooting in this context - distant aircraft - is that it is next to impossible to gauge the fall of shot. If you are firing a MG at a land target - or a hose at a pot plant - you can see where the shots are hitting the ground and make adjustments. Not so in the case of a flying aircraft 500m or so away.

 

So the "hosing" metaphor is misleading - just like the "sniping" metaphor.  A very small group is ideal for a sniper because he only wants to fire one shot, and wants to know with high confidence where it will go relative to the point of aim. Completely different issue.

 

The stories about Clostermann et al, harmonization etc are completely irrelevant to the point at issue, which is not what is the ideal group size or harmonization for a pilot of some particular level of skill suitable for the typical types of shot he will be called upon to make: it is whether tiny or larger group will lead to more or fewer hits  in this particular type of shot.

 

No amount of assertion will establish that, because you do not know how many people have just missed who would have made a hit had the group size been larger. It is an empirical matter and we do not have the facts to be sure what the answer is. My hypothesis is that in the range that we have been discussing the group size would make little difference. I could be wrong: but none of us know a priori.  

[JtD]

Well, all I know is that historically most shots missed because of poor aim. Dispersion was irrelevant.

 

In a US study of German guncam of 'good' attacks against bombers, dispersion of attack was about 15-20 mils for 50% of the rounds. Gauss-distribution assumed, this means an about 40 mils error for near 100%.

Mind you, only about half the attacks qualified as 'good' attacks in the first place, and also consider that experienced pilots more frequently had a guncam than inexperienced ones. All in all, 40 mils is massively conservative and still higher by a factor of 5-20 than gun dispersion.

Like I said, dispersion was irrelevant.

[ZachariasX]

No amount of assertion will establish that, because you do not know how many people have just missed who would have made a hit had the group size been larger. It is an empirical matter and we do not have the facts to be sure what the answer is. My hypothesis is that in the range that we have been discussing the group size would make little difference. I could be wrong: but none of us know a priori.

As JtD just pointed out, most shooters shot at nothing but open sky. Indeed dispersion there is irrelevant.

 

But my main point is that scatter from an automatic weapon is a whole different animal than scatter from a shotgun. This is because with the shotgun, all shot will be at the target at (for practical purposes) at the same time. With a machine gun, say it shoots at 600 m/s average bullet speed and .1 second cadence, one bullet its trailing the other by 60 meters. It is not a whole field that is covered with shot in a more or less even pattern that will strike the target as one.

 

The machine gun shoots one bullet after the other, drawing a lottery ticket with every singe shot as. You can thus fly through the bullets as there is plenty of sky between the bullets. Even if you look at the projection of the bullets in the assumed field of fire, some bullets are actually projecting on the airplane. But if the airplane can move in this one second, it might well be that it moved from the one bullet it might have hit it if the bullets arrived all at the same time like shot. Just because the total projected field of fire on the aircraft my show a hit, it is useless as this particular shot might not be there, where the target is, but before or after.

 

With the shotgun, chances of hit are high because you fire shot like one "huge bullet" that requires less precision to be placed upon a target.

 

With the automatic weapon, in the example I gave above when your gun has a field of dispersion 10 times the cross section of your target, chances are 10% for each shot fired when you have perfect aim. In theory, it is possible to fire a million shots at the target and still miss.

 

Here, to ease up things, a proud example of scatter:

 

 

 

 

 

Drawing of a 10% chance ten times assuming you will be lucky are not good odds when your life depends on it, and much worse it is the best option you have. Remember, the alternative is ten times a 100% chance to hit.

 

The "dispersion" made by misalignement of the guns don't add dispersion in the sense of what we're having with the MG151 here. It creates several hitspots in the sky at the determined shooting distance where bullets hit precisely. The problem with that is, out of 6 guns (4 not to speak of) in a Spitfire, only 1 gun can hit the aircraft, no matter how exact you're aiming. Clostermanns personal "mole view" of the bigger picture is indeed taken with a grain of salt, but it is a testimony that misaligning the guns was a strategy performed for all those out there who couldn't hit anything propperly no matter how hard they tried. And they still fared badly. All aces were good shots. Also Clostermann was happy having his guns aligned properly. You can shoot down aircraft like that instead of just brushing them up and then go home and overclaim.

 

You may say, no, this "larger field of fire" produced by the scatter is easier to place on your target. Well, that doesn't help you at all. Remember, in the example with perfect placement, you get 10% hit probability per shot. Moving the scatter field from perfect position reduces the exposed crossection of the target in your "hitting field". Moving the center to the wingtip instead of dead center about halves the exposed crossection, meaning you get 5% chance to hit something less vital for each shot fired. This means, with 10 shots fired, you cannot expect a single hit.

 

Bottom line again: Dispersion makes it harder to hit something. It doesn't matter if you have a machinegun or single action rifle, your chances of hitting drop with your guns increased scatter. There is absolutely no way around that.

 

Also consider that bringing along all those rounds to create your barrage, they are a weight penalty to your aircraft. Ammo is very, very heavy heavy. No, there is no place in batte for just fireworks.

[unreasonable]

Come off it Z!    A plane moving "out of the way" of one bullet is just as likely to be moving into the path of another. Provided that the target is within the group for the duration of the burst, the average number of hits for a large sample of bursts is identical whether the shells arrive simultaneously or one after another. The only difference is that sometimes a plane might "catch" two shots, or more, or none, when a stationary target (relative to the group) would only catch one.  The average number of hits is the same. 

 

As I have said all along, if you want to maximize the number of occasions on which you get, say 5 hits in a 10 round burst, then you do indeed need a very small group.  That might be an optimum dispersion pattern for a very good shot: but it is unlikely to lead to the highest number of hits for the whole population of shooters. It is possible - but that depends on the range of error in the aim of the population, which you do not know, which is why your talk of the perfect aim case gets nowhere.

 

Just look at the real world.  If it were true that "Dispersion makes it harder to hit something"  we would all shoot at flying ducks with M-16s instead of shotguns, or only shotguns with a full choke.   Just in case you have never used a shotgun, here is what wiki says about choke: "For shooting most game birds and clay pigeons, a desirable pattern is one that is as large as possible while being dense enough to ensure multiple hits on the target."   There is an optimum spread for any given target and range, it is simply nonsensical to claim that a smaller group is always better for any multiple projectile attack.

 

Harmonization of multiple guns, ammo weight etc are all irrelevant. 

[ZachariasX]

f it were true that "Dispersion makes it harder to hit something" we would all shoot at flying ducks with M-16s instead of shotguns,

No. We don't to that because

 

scatter from an automatic weapon is a whole different animal than scatter from a shotgun. This is because with the shotgun, all shot will be at the target at (for practical purposes) at the same time.

Why you use shot (and fire of all pellets at once) is because the chances of hit is higher because hitting chance of each pellet adds up.

 

Taking the analogy of the lottery again to show you why nobody on earth likes scatter in rifles/machine guns.

The shotgun approch is the following: Buy a lot of lottery tickets for each game drawn. (lots of shots in ONE slug) With increasing number and spread, the highet are your chances to be lucky.

The machine gun approach using scatter is the following: You buy one ticket per game, but you keep on playing lots and lots of rounds.

 

Just look at the real world.

I do. I find nobody that wants scatter as a feature of an automatic weapon. Name me one.

 

Harmonization of multiple guns, ammo weight etc are all irrelevant.

It is the essence of bringing a good weapon in the field. You want to accomplish your mission with the minimal effort. It is actually how you asses aircraft guns. You calculate their weight and time needed needed per air kill. There are other factors like reliability and availability, that for incance make the rather heavy Cal.50 Browning gun still a good solution. But increasing the reqired number of rounds fired is against every logic.

 

Imagine yourself as a soldier. You would be given the chice of two different (automatic) assault rifles. One hits precisely where you aim plus 100 rounds of ammo. Or alternatively one that shoots in the general direction of where you aim plus 10'000 rounds of ammo. What is your choice? Why?

 

But this is as far as I want to take my point. Maybe I'm a little oversensitive to this, but believe me, we've spent many weeks shooting at moving aircraft

 

 

such as these

 

 

and hitting rates (For the bag! Not the aircfaft! Although close shaves did occur. You could see him dropping the bag and dive away, tossing the bag, later followed by a nice phone call.) were poor even with good barrels. With more scatter, you didn't even need to sit on the cannon. You positively hit NOTHING with worn barrels and their increased scatter. And that is the real world experience I can bring.

 

So much for that. Never mind my traumas.

Edited September 28, 2017 by ZachariasX

[JG13_opcode]

edit:  never mind, I'm not going to even engage with some philosopher on the internet who thinks that assault rifles are built with inherent dispersion as a feature.  That's just comical.

Edited September 28, 2017 by JG13_opcode

[JtD]

edit:  never mind, I'm not going to even engage with some philosopher on the internet who thinks that assault rifles are built with inherent dispersion as a feature.  That's just comical.

So assault rifles are a prime example of long range precision attacks in fully automatic mode, where gun dispersion is the most important factor for the eventual accuracy of the fire?

[JG13_opcode]

So assault rifles are a prime example of long range precision attacks in fully automatic mode, where gun dispersion is the most important factor for the eventual accuracy of the fire?

Please don't put words in my mouth, that's beneath you. This quote:

 

It is a fact that many automatic weapons are designed to produce a specific size group - not necessarily the minimum that is possible - for precisely these reasons.

Indicates a fundamental misunderstanding of government procurement, the principles of marksmanship, and I would argue the fundamentals of economics and design.

 

You don't have the "minimum possible" dispersion because it's cost prohibitive. That is NOT the same thing as purposefully introducing inaccuracy to the weapon as a "feature" and it is not the same thing as setting up the guns in the P-47 to harmonize into a kill zone rather than a point.

Edited September 28, 2017 by JG13_opcode

[unreasonable]

snip

 

Indicates a fundamental misunderstanding of government procurement, the principles of marksmanship, and I would argue the fundamentals of economics and design.

 

You don't have the "minimum possible" dispersion because it's cost prohibitive. That is NOT the same thing as purposefully introducing inaccuracy to the weapon as a "feature" and it is not the same thing as setting up the guns in the P-47 to harmonize into a kill zone rather than a point.

 

I have said all along that the issue of harmonization is entirely different, which is why I am getting fed up with people raising it: we are simply talking about what is the optimum spread for a single gun. 

 

An example of when a too small group is highly undesirable is a heavy machine gun in sustained fire mode on a tripod.  You want the group to be small enough to engage a target such as an enemy MG emplacement, but large enough to create a beaten zone. A HMG has to be able to function as an area weapon, and it cannot do that if all of the shots fire into too small a space.  Hitting a man with a single 7.62 round is generally quite enough: having the whole burst hit a single man serves no useful purpose.  This is completely different from an assault rifle that has to be accurate for single shots, and where an area affect is achieved by the operator swinging the rifle around.  At least that is what is what I was taught at Sandhurst and as an infantry officer.  As a philosopher I was taught not to bring irrelevancies into discussions or use ad hominem comments. I suppose the temptation is that if you load enough of them into your post you get a wider dispersion, so one of them might hit?

 

 

 

Taking the analogy of the lottery again to show you why nobody on earth likes scatter in rifles/machine guns.

The shotgun approch is the following: Buy a lot of lottery tickets for each game drawn. (lots of shots in ONE slug) With increasing number and spread, the highet are your chances to be lucky.

The machine gun approach using scatter is the following: You buy one ticket per game, but you keep on playing lots and lots of rounds.

 

I do. I find nobody that wants scatter as a feature of an automatic weapon. Name me one.

 

It is the essence of bringing a good weapon in the field. You want to accomplish your mission with the minimal effort. It is actually how you asses aircraft guns. You calculate their weight and time needed needed per air kill. There are other factors like reliability and availability, that for incance make the rather heavy Cal.50 Browning gun still a good solution. But increasing the reqired number of rounds fired is against every logic.

 

Imagine yourself as a soldier. You would be given the chice of two different (automatic) assault rifles. One hits precisely where you aim plus 100 rounds of ammo. Or alternatively one that shoots in the general direction of where you aim plus 10'000 rounds of ammo. What is your choice? Why?

 

<snip>

 

 

 

 I have snipped a bit out because you keep making a lot of points which are not relevant:  machine guns are not rifles, ammo, harmonization etc.   

 

We are talking about the difference between say 3.5 mills and 2 mils - or even if 3.5 would make a difference compared to 3.0, if the MG151/20 is incorrect as SuperEtendard's experiment suggests.  The question is would 3.0 mils lead to better results than 3.5, not should you be spraying shots all over the sky.  I have not said that a larger group is always better - I am saying that a small group is not necessarily better.  The shotgun example, which I think is irrefutable since it is about hitting a single moving target, and the HMG sustained fire mode, which perhaps you did not know about, demonstrate this.

 

There is a statistically optimum group size for each combination of number of projectiles in the group, target and range, shooter accuracy and the required number of hits to make an effective kill. 

 

If you are sniping with a rifle,  you have an accurate shooter (one hopes) and only require one hit per target - edit: indeed you only have one shot per "burst".  You want a zero size group.  If you absolutely must make multiple hits, say firing at an He111 with rifle calibre MGs, then having a very large group that increases the chances of making single hits but reduces the chances of making many hits is undesirable.

 

In the case under discussion - 500m zero deflection shot on a fighter with a 20mm cannon, my hypothesis is that any singe hit is likely to be effective - even if will rarely destroy the aircraft, it will probably render it much easier to catch and kill.  Multiple hits are nice to have, not essential.  In which case maximizing the total number of occasions when a hit is scored is the key - not the number of occasions on which, say, three hits are scored.  If you think that is wrong, and say a minimum of three hits are required, then you will need a smaller group for the same number of shots.   

 

My point is that no-one here knows what the optimum size group is because no-one has all of the facts needed to calculate it, especially the most important, shooter accuracy. So far I see little attempt to even address this issue, let alone refute it.

Edited September 29, 2017 by unreasonable

[JtD]

There is a statistically optimum group size for each combination of number of projectiles in the group, target and range, shooter accuracy and the required number of hits to make an effective kill.

I put that into a chart. Assume a 4 mil target (2m diameter at 500m distance) and fire guns with varying dispersions.

Best gun for 1 shot = 1 hit (100% accuracy): lowest dispersion possible, 1 mil works inside of 3 mils aiming error (+/- 1.5)

Best gun for 3 shots at least 1 hit (33% accuracy: 3 mils dispersion - works inside of 4.4 mils aiming error (+/-1 2.2)

Best gun for 5 shots at least 1 hit (20% accuracy): 7 mils dispersion - works inside of 5.7 mils aiming error (+/- 2.85)

Best gun for 10 shots at least 1 hit (10% accuracy): more than 10 mils dispersion.

The downside is that large dispersion guns that give you a good chance to score a single hit, even when aiming poorly, don't really give you a good chance to score multiple hits, even when aiming properly. The 7mils dispersion doesn't give you more than 33% to-hit chance even when your aiming is spot on.

 

Anyway, in practice systematic errors don't exist like that, and all is put together into one common random error - aiming, piloting, environment, gun performance. As stated above, the better ~50% of attacks carried out by experienced Luftwaffe pilots shooting easy targets showed roughly 40mils dispersion. If that included a 9mils gun dispersion, and you'd reduce that to 0mils, you'd end up with 39mils attack dispersion. Negligible effect. Which is why pilot training and aircraft stability were so much more the focus than straight firing guns.

Edited September 29, 2017 by JtD

[ZachariasX]

There is a statistically optimum group size for each combination of number of projectiles in the group, target and range, shooter accuracy and the required number of hits to make an effective kill.

I think I got your reasoning and I used to think like that with the idea of the "hitbox" until I was handed such weapons.

 

In the real world

pilot training and aircraft stability were so much more the focus than straight firing guns.

that is what matters. You cannot compensate for aim.

 

If that included a 9mils gun dispersion

That is actually a very big scatter. Ten mil is what you try not to exceed for 3 shot salvos with assault rifles. That is more difficult than you might think. You can rock an airframe considerably for that dispersion.

 

Also, a machine gun is like a rifle, an ordinary gun. It just can keep shooting. But a gun doesn't scatter randomly. It exerts force on you while shooting, a lot of force twisting your aim away from where you are aiming to. And that is why even JtD's nice example is slightly misleading. Time is required to keep the gun on the target to shoot all rounds of a salvo and during this time, the gun is working against you. It also is more difficult to keep the sights perfectly on target for 1 second than for .1 second. This is why in the real world, your hit probability is much lower than on JtD's graph.

 

The increasing scatter just makes that more difficult. as I keep on repeating. Unless in the case of course when the Chinese (or whoever your BöFei supposedly is) agree to put up their stooges on a stand so that you can let go at them with all time in the world. I'm telling you, the enemy moves considerably when you shoot at him. Say, he is taking a dump and you are shooting at him with an automatic weapon. You miss with the first shot, you will be surprised how fast he'll start moving if you miss the first shot and if you don't start tracking immediatly he will have left your sights by the time you finished your burst. So you'd be placing your "hitbox" over a very blurry target.

 

Scatter in a gun, in the real worls is mainly a function of the cost making it. The Sten Gun ot the Walther WA 2000 are good examples for that. As long as scatter is low enough to hit your target in the envisioned fighting range, the scatter is tolerated. And by hitting it means possibility of hitting with individual shots.

 

You miss with the first shot, you're not likely to hit at all.

 

Plus your shooting likes to walk away from the target (and the target away from you, if it still can). That's what it does. Not the other way around. The only way that your target walks inside your fire, that is when you shoot a barrage and the other does the stupid thing.

 

And as for aircraft to conclude, as JtD writes

If that included a 9mils gun dispersion, and you'd reduce that to 0mils, you'd end up with 39mils attack dispersion.

There is just no way around a good aim. Unless you shoot nukes at the other.

Edited September 29, 2017 by ZachariasX

[FTC_Riksen]

Im not a real pilot, nevermind a WW2 pilot but in the game I definately prefer to know and be able to predict where my shot will go than to make aim and have my shot take a random course due to dispersion. I assume the real fighter pilots also prefered that way but I could be wrong. If one is able to aim, scatter is the worse thing that can happen during your shots ...

Edited September 29, 2017 by 4./JG52_Riksen

[unreasonable]

Aim obviously matters - if your target is not in your group, you cannot hit.  I said right from the very beginning that the assertion that a larger group size would reduce the ShVAK "sniping" problem was not necessarily true, precisely for this reason.  Which is the particular case that we were discussing - not a general point about the best overall cost effective solution for gun/ammo system grouping across the broad range of uses.  If you increase the group size, some of the shots that previously hit will now not, but some that previously missed will now hit. You cannot deduce the total change in hits unless you know both sides of the equation.

 

I gave the examples of the deliberately induced dispersion in both shotgun choke and sustained fire MGs, to illustrate the issue.  Another one would be if you are designing an assault weapon to produce a three round burst, you absolutely do not want the smallest possible group. In that case you want a group size to give a  soldier the maximum chance of scoring one hit at the typical combat range you expect, given the typical accuracy of soldiers under combat conditions.  For single aimed shots you want the smallest group you can affordably design in - which also depends on how well the ammunition is standardized. You might have to compromise between the two.

 

It may well be the case that for aircraft cannon and MGs the smallest practical group size is best overall: I do not know. but that is not something I have ever raised.

 

Z, You are not the only one here who has handled automatic weapons.  I am leaving this thread now - pretty tired of being misrepresented, and I have a production deadline for my soon to be released IL-2 007 movie.

[ZachariasX]

Z, You are not the only one here who has handled automatic weapons. I am leaving this thread now - pretty tired of being misrepresented, and I have a production deadline for my soon to be released IL-2 007 movie

The world would much of a better place if I was the only one using them. If I misrepresented you, that was not my intention. I just tried to therad on your reasoning and tried to point out where I see it falling short of the real world application. But you're right, let's leave it at this.

 

Either way, looing forward for your movie.

[JtD]

Will Bond use automatic guns?

[ZachariasX]

Ask Q.

[III/JG52_Otto_-I-]

By the way .. Why we have a ballistic discussion in a thread for FM (Flight Model) discussion?

Or ..Must we take in account that the exaggerated wobble of the Bf-109 at low speed (due to bad FM), is affecting to the gunnering accuracy?   

For example, .. Unlike the Yak´s, they have almost nothing of wobble at low speed especially with the FLAPS DOWN.   
 

Edited September 30, 2017 by III/JG52_Otto_-I-

[Guest deleted@83466]

 

By the way .. Why we have a ballistic discussion in a thread for FM (Flight Model) discussion?

Or ..Must we take in account that the exaggerated wobble of the Bf-109 at low speed (due to bad FM), is affecting to the gunnering accuracy?   

 

For example, .. Unlike the Yak´s, they have almost nothing of wobble at low speed especially with the FLAPS DOWN.   

 

 

 

I think if real BF-109 flew as easy and effortlessly as you wish this one to fly, they shouldn't have called it a BF-109, they should have called it 'Concorde.'

Edited September 30, 2017 by Iceworm

[III/JG52_Otto_-I-]

I think if real BF-109 flew as easy and effortlessly as you wish this one to fly, they shouldn't have called it a BF-109, they should have called it 'Concorde.'

You have no idea, .."Concorde" was a flying brick, ..she was all, but nothing "easy" to fly ..Please read more about airplanes.      

By the way British test of the Bf-109E said that: ""the controls of this aeroplane are pleasantly light at all speeds up to about 250 m.p.h ".[400 km/h] "

What the mean of "pleasantly light" for you??  .. You must pull like a mule?  

 

[Guest deleted@83466]

You have no idea, .."Concorde" was a flying brick, ..she was all, but nothing "easy" to fly ..Please read more about airplanes.      

By the way British test of the Bf-109E said that: ""the controls of this aeroplane are pleasantly light at all speeds up to about 250 m.p.h ".[400 km/h] "

What the mean of "pleasantly light" for you??  .. You must pull like a mule?  

 

 

I was referring to being able to enjoy a glass of champagne without so much as a ripple forming on the surface because the ride is so smooth...

 

I said that I was going to spend more time in the 109, and I've just started that, so I'll tell you my impressions:  At 400 kph, the controls feel as "pleasantly light" to me as any plane I've flown in this game.  When you get up to about 550 - 600 kph, the controls start to get heavy, just like historical accounts say they should.  Too much, too little? don't know... Lots of people were complaining about "wobbling" before the 2.012 update, but as a result of that update, it seems that the wobbles are quite minor, at least to me.  In fact I hadn't noticed them before.    Since this thread is about gunnery, I have not yet encountered a situation that inclined me to believe that the aircraft or it's guns were the reason for a missed shot...

Edited October 1, 2017 by Iceworm

[StG2_Manfred]

I think if real BF-109 flew as easy and effortlessly as you wish this one to fly, they shouldn't have called it a BF-109, they should have called it 'Concorde.'

 

In that comparison one consider the La or the Yak as an Extra 300. I have not read only one post where you questioning allied plane performance!

 

[Edited]  ~200 posts from you, only trolling! I recommend to ban you from forums and multiplayers - you're just a shame - 

Edited October 3, 2017 by Bearcat

[Guest deleted@83466]

In that comparison one consider the La or the Yak as an Extra 300. I have not read only one post where you questioning allied plane performance!

 

You are a troll. ~200 posts from you, only trolling! I recommend to ban you from forums and multiplayers - you're just a shame - 

 

Like I've always said to guys like you, go ahead and fly the Yak, the La-5, or any other VVS aircraft.   If you are so frustrated with the 109 then stop flying it, and show how much easier and better the Yak or La-5 is.  Prove that the Russian aircraft are what you believe them to be, and that 109's have all the handicaps you believe them to have. 

Edited October 1, 2017 by Iceworm

[BlitzPig_EL]

Manfred, must you always get personal?

 

Can we please get back to discussion of FACTS, not FEELINGS, please.

[III/JG52_Otto_-I-]

Like I've always said to guys like you, go ahead and fly the Yak, the La-5, or any other VVS aircraft.   If you are so frustrated with the 109 then stop flying it, and show how much easier and better the Yak or La-5 is.  Prove that the Russian aircraft are what you believe them to be, and that 109's have all the handicaps you believe them to have. 

Yes my friend, i've proved the Russian aircraft's, and i feel the differences between Bf-109 and Yak-1, Mig-3, etc. And yes I´ve used the "magic" flaps of the Yak against Bf-109´s. With the flaps down the Yak  is very stable, no wobble, no vibrations, at any airpeed and is more easy hit a target, than the Bf-109.

Is that the real behaviour of the Yak-1 flaps ??  ..I think not. 

As far as I know, The opening of the the pneumatic flaps generates flutter and a lot of disturbances if you tried to open them at high speed. And when flaps are totally open, they stop the airplane in the air with the danger of fall like a stone. That is the reason because in the real Yak manual the flaps is only mentioned for landing, 

[BraveSirRobin]

Is that the real behaviour of the Yak-1 flaps ??  ..I think not. 

 

Based on many hours of RL Yak-1 stick time, I assume?

 

And when flaps are totally open, they stop the airplane in the air with the danger of fall like a stone. That is the reason because in the real Yak manual the flaps is only mentioned for landing,

 

That sort of behavior doesn't really sound too useful for landing.

[unreasonable]

 

By the way .. Why we have a ballistic discussion in a thread for FM (Flight Model) discussion?

<snip>

 

 

Best place to have it: since it is about the modeling of the flight of the projectiles. 

 

The other advantage is that it is (or should be ) held under FM sub-forum rules, which are supposed to ban all of these my side/your side squabbles and focus on the theory and evidence alone.

[Guest deleted@83466]

 

Yes my friend, i've proved the Russian aircraft's, and i feel the differences between Bf-109 and Yak-1, Mig-3, etc. And yes I´ve used the "magic" flaps of the Yak against Bf-109´s. With the flaps down the Yak  is very stable, no wobble, no vibrations, at any airpeed and is more easy hit a target, than the Bf-109.

 

 

 

With all due respect, you've proved what, and to whom? 

[-=PHX=-SuperEtendard]

With all due respect, you've proved what, and to whom? 

 

He meant tested/tried. In Spanish "to test" and "to prove" are the same word and it's closer to the latter ("probar"), a case of "got lost in translation".

Edited October 2, 2017 by -=PHX=-SuperEtendard