Flak Guns

[castor troy]

ORIGINAL: che200

The problem is it is still a game Castor and JFBs have to have a chance as well or otherwise you will not find players to play you.

that´s true but afterall, I´m not bitching about things being one sided, most things go for both sides anyway. And you should know, I am a JFB. I´m only playing the Allied in my PBEM because I am just too lazy to spend halve an hour per turn to do resource and oil logistic and the additional 15 min per tun to do the pilot transfer. This is no critics, we wanted to have those things, there you go. I guess out of 15 or so PBEMs WITP I only had 2 or 3 games going as the Allied.

[JWE]

ORIGINAL: castor troy
But given the fact that ceiling in the game means something different than in real life, my question a page earlier was answered anyway. It also has solved the 6000ft WITP problem which seems to be the 10000ft standard height now. Or is this also wrong?

I'm afraid that is not quite correct. The term 'ceiling' has several well understood meanings in real life, when applied to a gun. There is ballistic ceiling, engagement ceiling, effective ceiling, all of them called ceiling. Indeed, the ceiling term most often reported is ballistic ceiling, because it is physical quantity of a tube/round combination. However, it is also the most meaningless in terms of a ceiling parameter a battery commander or gunnery officer would find useful. They, and the game, use the other ceiling parameters (effective/engagement ceiling). Just for example, a .50 cal Browning M2HB has a ballistic ceiling of ~15,000 feet, an engagement ceiling of ~4,500 feet, and an effective ceiling of ~3,000 feet. Please, oh please, don't suggest the .50 cals should be smiling and dialing up to 2.6 miles (4.2 km).

And yes, the engagement ceiling is a rather hard number (except read on). Pilots usually know what this is and it's a decades old no-brainer to try and fly above a flak envelope. However if the engagement ceiling is 9800 feet, this does not mean that 9801 is safe, or even that 9900 or 10000 is safe. The game adds some 'fuzzyness' to the ceiling number, so some guns might get an extra 1% or 2%, here and there, now and then, just to keep the airfarce boys on their toes.

[Bearcat2]

http://www.youtube.com/watch?v=CUl1mAjTTb0

I like this movie, the ammo clips may be fake[weight], but gives an idea of how the 25mm triple mount worked.

[mikemike]

ORIGINAL: JWE

I'm afraid that is not quite correct. The term 'ceiling' has several well understood meanings in real life, when applied to a gun. There is ballistic ceiling, engagement ceiling, effective ceiling, all of them called ceiling. Indeed, the ceiling term most often reported is ballistic ceiling, because it is physical quantity of a tube/round combination. However, it is also the most meaningless in terms of a ceiling parameter a battery commander or gunnery officer would find useful. They, and the game, use the other ceiling parameters (effective/engagement ceiling). Just for example, a .50 cal Browning M2HB has a ballistic ceiling of ~15,000 feet, an engagement ceiling of ~4,500 feet, and an effective ceiling of ~3,000 feet. Please, oh please, don't suggest the .50 cals should be smiling and dialing up to 2.6 miles (4.2 km).

And yes, the engagement ceiling is a rather hard number (except read on). Pilots usually know what this is and it's a decades old no-brainer to try and fly above a flak envelope. However if the engagement ceiling is 9800 feet, this does not mean that 9801 is safe, or even that 9900 or 10000 is safe. The game adds some 'fuzzyness' to the ceiling number, so some guns might get an extra 1% or 2%, here and there, now and then, just to keep the airfarce boys on their toes.

To reinforce what JWE said: practically every AA projectile with explosive content in WW2 had a self-destruct feature, including VT-fuzed shells. Remember that a heavy AA battery can fire several tons of shells per minute; fragments raining down are bad enough, but you really wouldn't want shells to come down in one piece; that would make it nearly irrelevant for the attacker to drop bombs at all.

Now, here is some data about German AA guns and their ballistic ceilings and fuze limits (I'd expect Allied ammo to be in roughly the same ballpark):

gun....................maximum.......fuze..........(in feet)
20 mm.................3700 m........2200 m.....12130/7210
37 mm.................4800 m........3500 m.....15740/11475
Bofors..................6700 m........4300 m.....21970/14100
30 mm MK103......4700 m........1600 m.....15410/5250
88 mm Flak37....10600 m.......10600 m.....34750/34750
88 mm Flak41....14700 m.......12350 m.....48200/40490
105 mm Flak39..12800 m.......11800 m.....41970/38690
128 mm Flak40..14800 m.......12800 m.....48520/41970

(This shows, BTW, why the MK103 was not a success as an AA gun, it had less effective range than a 20mm, even if the shell was three times as heavy.)

The fuze limits represent the maximum distance a shell can travel before it self-destroys and should more properly be seen as a time limit, i.e. the maximum "life" a shell has after being fired. This corresponds with the maximum possible ceiling for a shell if it is fired vertically upwards, but remember that this can still be rather beyond the range where you can expect a reasonable hit probability.

[JuanG]

ORIGINAL: castor troy

ORIGINAL: Sardaukar

ORIGINAL: castor troy




so it was relatively safe for the Japanese in real life to attack above 10.000ft because only 75mm, 90mm and the big calibre British guns could reach them? [&:] 10.000ft doesn´t really sound high to me and 10.000ft is definetely an altitude in the game from where you get excellent hit rates. 10-11000ft in AE seems to have replaced the 6000ft from WITP. Japanese AA above 10.000ft seems not to be existing but also the Allied is pretty weak if you don´t have a couple of those base forces with two dozen heavy calibre guns each.

You do not really know, what you talk about, do you?

I suggest you'd do some research about weapons before stating that 40mm "reaches 20k" etc. Your sources suck apparently, if they are anything else than Wikipedia. 40mm like so many others, had rounds had self-destruct device designed to go off either when tracer burned out or it was timed. You cannot hit anything above or beyond certain limit, if round is no longer there, do you?

Maybe you could buy some books from for example here: http://www.quarry.nildram.co.uk/miltech.htm

You could also benefit for his articles he provides for free on that page.

Maybe you could occasionally also check: http://www.navweaps.com/

It's free too. [:'(]

When I rant, burden of proof is on my side. I also try to bring in references supporting my point of view. It works same for you.

Frankly, your constantly negative ranting about everything makes you prime example of person to others to use "green ball" on this forum. Didn't I tell you I don't like you?

lol, funny post smart ass, as if I would care. wikipedia? You can clean your arse with it.

Navweaps is a site that isn´t only known by you, mind you.

Navweaps states for the 40 mm/56 (1.57") Mark 1, Mark 2 and M1 an AA ceiling of 22,299 feet (6,797 m) which is pretty much what I´ve written in a post before the one you quoted. So instead of giving an offending answer you should first check it yourselve. So considering I´ve stated that all sources I know of are stating a ceiling of 20.000ft plus I´m pretty much spot on.

You can correct me if I´m wrong, but I guess I haven´t said that it is effective up to 22,299 feet but it´s the ceiling of the gun. If "ceiling" in the game means EFFECTIVE height to engage a target then I feel of course sorry that the game says ceiling but it means something else. My fault probably.

And did I ever tell you I like you? I guess not. [:'(]

Suggestion from someone who has used and uses NavWeaps regularly - read the small print.

Under the "Range - USA" section;
1) USA produced HE-SD ammunition was set to detonate at 4,000 - 5,000 yards (3,700 - 4,570 m) so as to minimize problems due to "friendly fire." HE and AP rounds that did not self-destruct were also manufactured.

Under the "Range - UK" section;
Note: British rounds normally self-destructed at 3,000 - 3,500 yards (2,700 - 3,200 m), but this was increased to 7,000 yards (6,400 m) in some ammunition types.

Other sources support this, and these were both standard issue for ships due to the "close in" allied AA escort tactic.

Also, suggest you do a little research on the difference between "Effective Range" and "Ballistic Range" for AA purposes, as Time of Flight increases very rapidly after a certain a point, and with it, the difficulty of hitting a target moving at 200mph.

[Dili]

castor troy let's suppose the round didn't had a timer and destroyed itself, the round would continue to go up with increasing less velocity then would start to tumble and reach 20000ft with zero speed then will start to fall, this of course would depend also on wind at altitude the round is. Impossible to hit anything reliably above 3km with a Bofors it will be a waste of amno. A plane above 3km of a Bofors gun is safe, a plane above 1-1,5km above a 20mm gun is safe, a plane above 6-7km for a 75mm AA gun is safe, a plane above 8-9km for a 88mm is safe.

For example a present day Bofors have range around 12km(achieved at 45 degree tube elevation) but the efective AA range is 4km or less, because that is distance that the round has ballistic properties that make it predictable.

[castor troy]

ORIGINAL: Dili

castor troy let's suppose the round didn't had a timer and destroyed itself, the round would continue to go up with increasing less velocity then would start to tumble and reach 20000ft with zero speed then will start to fall, this of course would depend also on wind at altitude the round is. Impossible to hit anything reliably above 3km with a Bofors it will be a waste of amno. A plane above 3km of a Bofors gun is safe, a plane above 1-1,5km above a 20mm gun is safe, a plane above 6-7km for a 75mm AA gun is safe, a plane above 8-9km for a 88mm is safe.

For example a present day Bofors have range around 12km(achieved at 45 degree tube elevation) but the efective AA range is 4km or less, because that is distance that the round has ballistic properties that make it predictable.

there is no doubt on what you say, never have I said the effective ceiling would be 20.000ft+ even if everyone insist that I said so... the in game info screen on AA guns says CEILING and that ceiling is obviously effective ceiling in the game.

[John Lansford]

Damage from friendly AA fire was a definite problem for the USN after 1944.  Enterprise twice was hit by AA shells that started serious fires among her on-deck planes; IIRC one of them was a proximity fused 5" shell that detonated over the deck, the other was a string of 40mm landing on the planes...

[JWE]

Effectiveness – must say this hasn’t really been looked at for AA AutoWeaps like it has in the case of Arty Anti-Soft. The numbers are generally the same as used in stock-WiTP. If one was to apply the same processing to this as was done for Arty A-S, here is how it might go.

Now, the idea is not necessarily to get an EFF number, rather it is to determine the relative ratio of EFF of one gun to another. The actual EFF value is/can be determined empirically and simply multiplied by the determined ratios. That way, everyone plays nicely together, but changing one requires changing all by the same % amount – keeping everything on the same page, so to speak.

First, is to look at the damage mechanism a round is designed to produce. This means explosive round calculations aren’t comparable to ball (that’s next). So, looking at explosive rounds, there’s several damage mechanisms: raw projectile kinetics (projectile wt), fragmentation kinetics (size and density), incendiary deflagration, blast induced structural deformation. Some of these are second and third order effects, so the primary damage mechanism – fragmentation kinetics – is the best (and easiest) to analyze.

There is a weight equivalence between projectiles, but also an equivalence between the explosive charge as a % of projectile weight. This has a direct relationship to the size and number of fragments (density) produced. But fragmentation density, as a damage mechanism, falls off in accord with an inverse power law (one reason a 105mm isn’t as big a killer over a 75mm given their relative projectile weights). So numerical analysis has to include some square-root calculations.

Ok, here we go: A 25mm has a .55lb projectile with a .020lb filler (that’s 3.6% fill); a US 1.1” has .92lb proj with .035lb fill (3.8%); a 20mm has a .27lb proj with a .024lb fill (8.9%); a 40mm has a 2.0lb proj with a .150lb fill (7.5%). In terms of shell wt %, and using the 25mm as the basis, the 25mm=1, the 20mm=0.5, the 1.1”=1.7, and the 40mm=3.6. In terms of fill % (a biggie), the 25mm=3.6, the 20mm=8.9, the 1.1”=3.8, the 40mm=7.5.

Now you have to leave the realm of raw numbers and enter the wonderful world of the physics of affectivity analysis. Raw effectivity is kinda a square root of ‘fill’, so there is an equivalence of root-fill; and again using the 25mm as the basis, the 25mm=1, the 20mm=1.1, the 1.1”= 1.3, the 40mm=2.7. And then there is damage physics which is also a square root quantity (to first order), so the equivalent EFF, at the sharp end, is adequately modeled by a Sqrt(fill equivalence). So what you get, at the end of all this crapucino, is:
25mm = 1.00
20mm = 1.05
1.1 in = 1.15
40mm = 1.65
So whatever EFF number is used as a basis, that is how the different guns should play with respect to one another. If basis is 10, then the 25mm=10, the 20mm=10 (or11), the 1.1”=11 (or 12), the 40mm=16 (or 17).

That is how I would do it. Some different things happen if you are shooting ball (13.2mm, .50 cal, .30 cal, etc..). It seems that affectivity changes and that raw round kinetics become first order. An interesting feature of the analysis is that at low altitudes (those within the engagement envelope of a ball firing AAMG) machine guns begin to have a larger relative damage affectivity than their explosive cousins. Fiz-iks, fiz-iks, it’s all fiz-iks.

[Sardaukar]

I think you also have to figure in pure kinetic energy from shell, which is considerable. 

[JWE]

ORIGINAL: Sardaukar
I think you also have to figure in pure kinetic energy from shell, which is considerable. 

Actually, Sardukar, that is not the case. Fuzed, explosive, shells have two degrees of damage freedom in the second order from shell weight, and three degrees of freedon in the third order from shell weight. They are not considerable given the primary damage mode.

Shell kinetics play a large part in analysis of affectivity of ball firing weapons, but are only analytically a root-2 or mainly a root-3 factor in fuzed weapons.

[edit] this the danger associated with pinging on a single parameter as though it made a difference. Four to six different things have to play in the same sandbox. A unified conceptual approach seems best when dealing with the game engine.

[Alfred]

ORIGINAL: JWE


...[edit] this the danger associated with pinging on a single parameter as though it made a difference. Four to six different things have to play in the same sandbox. A unified conceptual approach seems best when dealing with the game engine.

JWE,

How true! How true!

BTW, are you sure you really are a mild mannered lawyer dealing with patents. More of a renaissance man along the lines of a da Vinci, methinks.

Alfred

[Yaab]

Thread resurrection successful!

Does anybody know what are "AAA Auto-Weaps", mentioned several times in this thread by JWE? Are they the AAMGs only, or 20-25-37-40mm guns are also included?

[witpqs]

ORIGINAL: Yaab

Thread resurrection successful!

Does anybody know what are "AAA Auto-Weaps", mentioned several times in this thread by JWE? Are they the AAMGs only, or 20-25-37-40mm guns are also included?

I think it includes the 20mm, 25mm, 40mm. I'm not sure if the 37mm was auto or was it manually loaded? But if auto then it would be included. And the various MGs as you note.

Adding: Isn't there a 1.1 inch also?

[Yaab]

Seems AA guns of 20-40mm caliber fired 100-140 rpm, including 37mm M1A2 guns. Then, 75-90mm guns average 15-20 rpm - these are loaded manually.

Maybe any AA gun fed by a clip is an auto-weap,along with AAMGs?

There are those small IJA AA units consisting solely of 20mm AA guns and 13.2mm AAMGs, which have a slightly different LCU icon with adittional letters "MG". They are mostly in Kwantung at start. Their TOE is 2209 (DaBabes), and is called Auto-Weap TOE in Tracker. It is strange that the British all-Bofors AA regiments don't have the same icons - they also have only auto-weapons in their TOEs.