Video of Land Phalanx taking out bombs and mortar rounds.

You couldn’t possibly believe that.

Sniper rifle accuracy is described as the size of a group at a certain range, or more often a ratio of size vs range. MOA or minutes of angle roughly equate to about 25mm at 100m, or 1 inch at 100 yards. A group of 5 shots that are less that 25mm at 100m range would be considered sub MOA accuracy. An AKM with good ammo could make 2 MOA, while an average AKM with average ammo would make 6 MOA or worse. (obviously this gives an estimate of impact spread at larger ranges but that does not necessarily hold true… a sub MOA rifle might not even print on the paper at 1,000m.)

The point is that a 0.75 MOA rifle will record impacts in a cone of a diameter of 0.75 MOA. Other than that there is no pattern or curve that can describe how the projectiles make holes in the target… just that with a good shot, good ammo and maintained rifle the projectiles should hit within the circle. Replace the rifle with a water cooled twin barrel 30mm cannon and it will also have a cone of fire where the rounds will impact. This cone is effected also by the accuracy of the drives aiming the cannon (moving target) and also by the accuracy of the location of the target and in tracking the targets future position and laying the guns to follow that position. The muzzle sensor will update the computers as to the velocity of the shells to improve accuracy and the guns themselves may already be toed in or able to be toed in to concentrate their bursts for some targets at particular ranges but the accuracy of a gun that fires from a locked position that uses the gas from its shot to reload the other barrel suggests to me a much more accurate setup than a gatling barrel that moves contiuously. If the Gatling gun was the best idea the Soviets have plenty of gatlings in 23mm and 30mm to choose from when the tunguska was designed.

(You should also remember that both Tunguska and Pantsir have 8-10km range missiles that are equipped with proximity fuses that could also be used against small targets if necessary so even if the guns couldn’t engage a mortar shell the missiles certainly could.)

You couldn’t possibly believe that.

Like with a double-barrelled shotgun, if you miss with the first barrel, you might hit with the second … so why not fire the second first? 😉

For example, throwing dice is random, with a uniform distribution (which is probably what you’re thinking of as a “random distribution”). Things like test scores, height, etc. are also random, but with a z-distribution. Samples from data that are z-distributed have a t-distribution. There are other distributions for other purposes (e.g., f-, Chi-squared, etc. etc.)

I need to google up some images. I think we’re just talking past each other with the same general idea, and different terminology (my fault on that, never was much good at exact definitions.) 😉

Matt

If guns had a predictible pattern or projectile distribution then why fire bursts… surely if there is a pattern or known distribution then you should be able to tell which shell will hit the target and just fire that one…

You couldn’t possibly believe that.

A random distribution is just that, random.
A bell curve implies a pattern to the overall distribution, with a majority of incidences clustered near the designated center, and discrepancies tapering off toward the limits

Matt,

There is nothing called a “random distribution” as opposed to a bell (i.e., normal or z-) distribution. The events that comprise the distribution (i.e, the
random variable) cannot be predicted so you don’t know what the next event will be. However, the events as a whole do have a distribution. (If it weren’t so, most of statistics would not be possible.)

For example, throwing dice is random, with a uniform distribution (which is probably what you’re thinking of as a “random distribution”). Things like test scores, height, etc. are also random, but with a z-distribution. Samples from data that are z-distributed have a t-distribution. There are other distributions for other purposes (e.g., f-, Chi-squared, etc. etc.)

Obviously, you don’t expect a mathmatically perfect curve in a real sample, at least not on this planet, but the overall shape will have such a pattern.

Actually samples *will* be t-distributed (i.e., lower hump and thicker tails) if the underlying population is z-distributed. Also, the t-distribution is parameterized by sample size, so for small samples, the tails are very thick (so the distribution is very wide, implying larger uncertainty). However, as the sample size gets larger, the t-distribution approaches the z-distribution, and for sample sizes near 40 or so, there is almost no difference .

Most of this material is from an elementary probability and satistics course, but as I previously said, you can Google this.

Unless your guns are truly horrendous the rounds won’t be randomly distributed

If guns had a predictible pattern or projectile distribution then why fire bursts… surely if there is a pattern or known distribution then you should be able to tell which shell will hit the target and just fire that one…

I met a deck officer in the RN who said the Phalanx systems that they have are “always breaking down” but that Goalkeeper hardly ever had such problems.

I’ve worked with the Phalanx techs on 2 diffrent DDG’s and they tell me they are very reliable.
However, if they were Block 0 mounts with the hydrolics then I can see them having problems.
But comparing Goalkeeper to Phalanx is kind of silly because Phalanx was deisnged to to just bolt on where ever you had room while Goalkeeper you have to design the ship for it from the begining since it takes up space inside.

Unless your guns are truly horrendous the rounds won’t be randomly distributed and should follow the standard bell curve with the rounds being concentrated along the barrel axis.

In my experience of shooting once you have established the accuracy of a rifle, unless you make a mistake you can pretty much draw a circle of a particular size and the rounds will not adopt any particular pattern within that circle.
With a moving target there are tracking and aiming errors as well but they will also add a random bias that will mix up any pattern that might have been present anyway.

Look at most fired at targets and it is exceptionally rare for a nice bell curve pattern to be formed.

Even in the overlap areas you’re not going to have nearly as many rounds as around the centerpoint of a single barrel. Unless you’ve got more evidence than just your opinion I’m inclined to think such a setup has very little chance against a target as small as a mortar round.

If you want to talk about chance then two twin barrel guns firing 30mm calibre projectiles immediately has a better chance of hitting any target than a single barrel gun firing at a lower rate projectiles that are roughly .50 calibre.

This so called centrepoint you talk about is what I am talking about… at 1km it will be over 1m across and at 4km will probably be 5-6m across.

Remember, when it is flying towards you a HARM or ALCM is not exactly a large target either.

A random distribution is just that, random.
A bell curve implies a pattern to the overall distribution, with a majority of incidences clustered near the designated center, and discrepancies tapering off toward the limits

Obviously, you don’t expect a mathmatically perfect curve in a real sample, at least not on this planet, but the overall shape will have such a pattern.

BTW, I do agree, the exact type of distribution between a single and multi mount are pretty much irrevelent for intercepting a mortar shell, assuming that the bore axis difference remains a small percent of the engagement range.

Matt

Please, start again. You can have a random distribution, OR you can have a bell curve distribution.

No such thing as a random bell curve.

Matt

No — in this case I’m absolutely correct. Please Google “random variable” and “probability distribution”. This is also a reasonable place to start.

There is no contradiction between the two. In fact, the shells are likely randomly distributed in a bell curve.

Please, start again. You can have a random distribution, OR you can have a bell curve distribution.

No such thing as a random bell curve.

Matt

Actually I think that you are both right. 🙂

Unless your guns are truly horrendous the rounds won’t be randomly distributed and should follow the standard bell curve with the rounds being concentrated along the barrel axis.

There is no contradiction between the two. In fact, the shells are likely randomly distributed in a bell curve.

Even in the overlap areas you’re not going to have nearly as many rounds as around the centerpoint of a single barrel. Unless you’ve got more evidence than just your opinion I’m inclined to think such a setup has very little chance against a target as small as a mortar round.

True. However, the distance between the barrels is going to be negligible when compared to the engagement range. As a result, the two “cones” are effectively going to be a single cone.

Should I bother answering?

As I said before. Cannon are not lasers. You don’t just draw a straight line from the muzzle of each gun fitted to an anti aircraft gun and that is where the shells hit. Each muzzle that fires creates a circle of impacts. The more accurate the gun the smaller the circle is at different ranges. With a Phalanx there is a single firing point so although it has 6 barrels it acts like a single barrel gun. Of course because the guns are moving accuracy is rather less than with a fixed gun.
Fitting two seperate guns a couple of metres apart actually improves performance not just by increasing rate of fire. If you draw one circle for each gun for the Tunguska you will find that from 1km or closer the circle overlap. They overlap between the two guns. What does that mean? That means that between the two gun barrels there are twice as many shell hits than on the outer edge of the guns circles. If you scatter holes randomly within those circles where the circles overlap there will be impacts from both guns whereas where the circles don’t overlap there will be shell hits from one gun only.

Unless your guns are truly horrendous the rounds won’t be randomly distributed and should follow the standard bell curve with the rounds being concentrated along the barrel axis. Even in the overlap areas you’re not going to have nearly as many rounds as around the centerpoint of a single barrel. Unless you’ve got more evidence than just your opinion I’m inclined to think such a setup has very little chance against a target as small as a mortar round.

I met a deck officer in the RN who said the Phalanx systems that they have are “always breaking down” but that Goalkeeper hardly ever had such problems.

If you don’t think two widly spaced cannon are going to produce a bigger spread than a single barrel you’re even more retarded than I thought. With Gepard it doesn’t matter since it’s an antiaircraft weapon. I’ve seen NO claims that Gepard can shoot down mortar rounds. I also notice you didn’t answer the question which is an answer in itself. No surprise there.

Should I bother answering?

As I said before. Cannon are not lasers. You don’t just draw a straight line from the muzzle of each gun fitted to an anti aircraft gun and that is where the shells hit. Each muzzle that fires creates a circle of impacts. The more accurate the gun the smaller the circle is at different ranges. With a Phalanx there is a single firing point so although it has 6 barrels it acts like a single barrel gun. Of course because the guns are moving accuracy is rather less than with a fixed gun.
Fitting two seperate guns a couple of metres apart actually improves performance not just by increasing rate of fire. If you draw one circle for each gun for the Tunguska you will find that from 1km or closer the circle overlap. They overlap between the two guns. What does that mean? That means that between the two gun barrels there are twice as many shell hits than on the outer edge of the guns circles. If you scatter holes randomly within those circles where the circles overlap there will be impacts from both guns whereas where the circles don’t overlap there will be shell hits from one gun only. This means that a target in the centre of the line of fire will have double the chance of getting hit than if it were to the left or right of the point of aim.
The phalanx on the other hand will have a single circle that will likely be the size of the two circles created by the tunguska with a relatively even spread of impacts.

Are you serious?

Do you think that when a Gepard fires upon a target it will have two lines of 35mm holes with each shell hole 30cm from the previous hole along the side of the aircraft?

A burst of cannon shells forms a cluster around the aim point for any gun. Using two guns simply increases the number of shells heading toward the target. At most engagement ranges the clusters of two cannon overlap and increase shell density where the target is most likely to be.

If you don’t think two widly spaced cannon are going to produce a bigger spread than a single barrel you’re even more retarded than I thought. With Gepard it doesn’t matter since it’s an antiaircraft weapon. I’ve seen NO claims that Gepard can shoot down mortar rounds. I also notice you didn’t answer the question which is an answer in itself. No surprise there.

For the US Army the Phalanx is an affordable (read cheap) off the shelf solution.

It utilises spare explosive ammunition left over from the retired Vulcan system and an automated quick reaction capability combined with a high cyclical rate making it a desirable solution.

That and they can just get USN personel to maintain them.
One of my LPO’s just did a tour working on an Army Phalanx and he said it worked very well.
Also the Phalanx has another advantage, it was designed as a pretty much bolt on stand alone system that doesn’t take up any room inside a ship, so all the Army had to do was bolt all the equipment on the back of a semi-trailer.

With a target as small as a mortar round and two widly spaced guns on the mount how are they going to hit the target? Do they only aim one gun at the round? If they are angled slightly in to converge at a focal point how do they deal with a mortar round that isn’t in the “sweet spot”?

Are you serious?

Do you think that when a Gepard fires upon a target it will have two lines of 35mm holes with each shell hole 30cm from the previous hole along the side of the aircraft?

A burst of cannon shells forms a cluster around the aim point for any gun. Using two guns simply increases the number of shells heading toward the target. At most engagement ranges the clusters of two cannon overlap and increase shell density where the target is most likely to be.

Doesn’t the Stryker vehicle have a GAU-8 or something similar for air defence along with Stingers?

Combining weapons on a single vehicle reduces cost and makes the vehicle much more flexible but they need longer range weapons than stingers. The purpose of the missiles is to be able to defeat enemy anti vehicle missiles (fired from helos) beyond the range of the helos missiles. A ground launched AIM-9X would be much better (perhaps with a small booster rocket to get it airborne quickly).

AFAIK, they deleted it from the Burkes in favor of the SeaRAM. The latter wasn’t a success and so the Phalanx 1B will later be retrofitted to these Burkes. It’s just a matter of time.
Tor-M1 was also credited with free fall bomb defence.

Doesn’t the Stryker vehicle have a GAU-8 or something similar for air defence along with Stingers?

This is LAV-AD which the Marines were suppose to buy 17 of. Who knows where it actually ended up. They apparently were to be built with 8 Stingers and a 25mm Equalizer gatling (same as the AV-8B). The one in the second picture obviously has a longer set of barrels and it could be the four-barrel version of the GAU-8.

AFAIK, they deleted it from the Burkes in favor of the SeaRAM. The latter wasn’t a success and so the Phalanx 1B will later be retrofitted to these Burkes. It’s just a matter of time.
Tor-M1 was also credited with free fall bomb defence.

Doesn’t the Stryker vehicle have a GAU-8 or something similar for air defence along with Stingers?