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BigDon
2012-Jan-27, 02:19 AM
Does anybody know the largest caliber complete round currently in production?

I'm brainstorming with myself about the largest Vulcan-type chain gun you could make without having to produce new unique rounds for it.

The left half of my brain had to ask "What would you use an eight inch Vulcan with a 1200 round magazine for?" (Mentally modeled after my beloved Tomcat's 20mm chain gun)

It took the right half of my brain two minutes to come up with a reply.

The same principle that allows a relatively small caliber round just shred heavy armor should be able to gouge out and plumb deep bunkers without resorting to the polically questionable use of nuclear shape charges.

It would have to be naval, obviously. And would be limited to targets within 30 miles of the coast.

Even a 16 inch vulcan, though expensive, would be less of a technical challenge than let's say, a manned Apollo landing with a return mission.

and you get twenty more miles of range.

We would need another propellant system though.

(See what you post when to have White Russians with dinner!? :) )

Tensor
2012-Jan-27, 04:59 AM
I'm thinking that the 155 mm (6.1 inch) is the largest shell going. I just can't see a 16" chain gun. The 16"/50 calibre Mark 7 guns that were on the Iowa class Battleships weighed 267,900 pounds (including the breech). With a six barrel chain gun, you're looking at trying to move 1.6 million pounds, and that's just the barrels, with breech. Not even talking about the supports. Getting that much weight to rotate at any kind of good speed, reliably, just doesn't seem to be realistic. And, after all, if they just kept the Iowa class Battleships around, you could be firing 16" shells at 18 rounds per minute anyway (9 guns per ship, 2 rounds per minute).

IsaacKuo
2012-Jan-27, 06:41 AM
155mm isn't semi-fixed--the shells and powder are loaded separately. I think the largest semi-fixed round is 127mm (5 inch), used in some modern naval guns.

Tensor
2012-Jan-27, 06:55 AM
155mm isn't semi-fixed--the shells and powder are loaded separately. I think the largest semi-fixed round is 127mm (5 inch), used in some modern naval guns.

Cool, thanks for the correction Isaac.

Shaula
2012-Jan-27, 07:35 AM
You could think about a metal storm type arrangement? Bulky, possibly impractical but a high OMG factor.

swampyankee
2012-Jan-27, 10:55 AM
Maybe BigDon should consider a mitrailleuse.

Ara Pacis
2012-Jan-27, 12:38 PM
I don't know why you'd even want a Gatling-style gun. With artillery, you're using indirect fire instead of direct fire, so you have additional dimensions to play with. Instead of rapid fire, you fire rounds at different trajectories from the same gun so that they all arrive at the prescribed interval, and with enough additional guns you can keep that up indefinitely.

If you really want to dig out a bunker, then you may want to use some sort of penetrating round. The strength of the ogives on large caliber artillery rounds may not be enough to cause penetration to a deep bunker. Perhaps ship-launching BLU-113 bunker-buster bombs on rocket boosters would work.

I'm not even sure I understand how a nuclear shaped charge would work in atmosphere, I thought it would only be useful in vacuum. How would a differential emission of gammas/x-rays affect the yield and overpressure at the surface, and would the overall efficiency be reduced negating any difference in shaping the charge?

Personally, I'd put a mini-nuke in a BLU-113 body and expect that the radiation would stay underground, and if anyone did figure it out, it'd be a fait accompli.

glappkaeft
2012-Jan-27, 12:57 PM
155mm isn't semi-fixed--the shells and powder are loaded separately. I think the largest semi-fixed round is 127mm (5 inch), used in some modern naval guns.
The Bofors Bandkanon self propelled gun fired fixed 155 mm ammunition from a replaceable 14 round magazine. Emptying the magazine took 45 seconds but few where built due to the enormous cost and they where taken out of service in 2003.

BigDon
2012-Jan-27, 05:06 PM
Ara, well for one, if you did build a naval unit along those lines, it would have everybodies attention. Much like the freakin' Deathstar. :O

Well, since brainstorming is an ongoing process I recall this morning the US Navy is switching to rail guns.

This changes a lot of things about design needs.

If I recall correctly the Iowa's sixteen inchers could penetrate 50 feet of granite with armor piercing rounds. So how deep would a stream of thirty to sixty similar projectiles arriving within 1.5 seconds go? Not a similtanious time on target attack as the round ahead should excavate a channel for the round behind it.

Think of the main gun of the A-10 Warthog, the GAU-holycrapitspointedatus. It's not a big shotgun, (which have their uses to be sure) even if the rounds seem to hit similtaniously and I don't believe it would be be nearly as effective against MTBs and bunkers in "semi-auto mode".

Hey Swampy! Thanks!

The resulting wiki search reminded me there was a more practical absurd weapon I wanted to brainstorm, based on the Nockgun.

What do you think of a break open, five barrel 30.06? You could have a speed loader designed for it as well!

Though you may want to bench that somehow before you pulled the trigger...unless you're me of course. :whistle: May have to enclude a monopod with that.

I bet that guy who owns Red Jacket Arms on tv would build one if you ran the idea past him properly. (ie waved 5 to 6 grand in front of him.)

We need VonMazur in this discussion!

Gsquare
2012-Jan-27, 07:05 PM
Think of the main gun of the A-10 Warthog, the GAU-holycrapitspointedatus. !

Yep; Bid Don; that A-10 gatling gun is my favorite.....30mm - footlong shells coming at ya at about 4000 rounds per minute (Yikes!) can really ruin your day.. ;))

Nice clip here: http://www.youtube.com/watch?v=1Oc-xbpy-OI


If I recall correctly the Iowa's sixteen inchers could penetrate 50 feet of granite with armor piercing rounds. So how deep would a stream of thirty to sixty similar projectiles arriving within 1.5 seconds go? Not a similtanious time on target attack as the round ahead should excavate a channel for the round behind it.


Not with a standard naval 16 incher. Shells probably not accurate enough after barreling through the 20 miles air especially with required corrections for wind variation, density changes, coriolis, etc. A new GPS designed shell with guide fins would probably do the trick..
http://www.defenseindustrydaily.com/1726M-for-GPS-guided-Excalibur-155mm-Shells-06835/
G^2

Tensor
2012-Jan-27, 07:34 PM
If I recall correctly the Iowa's sixteen inchers could penetrate 50 feet of granite with armor piercing rounds. So how deep would a stream of thirty to sixty similar projectiles arriving within 1.5 seconds go? Not a similtanious time on target attack as the round ahead should excavate a channel for the round behind it.

I don't' think that 1.5 seconds probably would be any good. 3-4 seconds maybe, 5-6 would be more like it. The debris thrown up by the first shell would have to settle before the second shell arrives. Otherwise, the debris in the air could either throw it off target (even one carefully aimed with Gsquare's GPS shell), or possibly set off the arming fuze before the shell hits. Ending up with the shell not penetrating deep enough before the shell's main explosion.

dgavin
2012-Jan-27, 08:52 PM
I loved the A-10, there is just something so impressive about an aircraft who's main gun can apply more thrust backwards when firing, then it's engines can apply forwards!

If your looking to do some bunker busting, there is a better way which the navy (if i understand it correctly) is already researching. Rail Guns. If you fire something say the size of a Pin Ball at 1% the speed of light, aimed at say a 50 feet thick concrete barrier, it -will- destroy that concrete barrier, along with a good portion of anything nearby. Fire the same ammo at 10% the speed of light, and you get somethign on the order of megatons of energry release, without much radiation.

The main issue with rail guns, or other fast ammo, is keeping the ammo once it's over mach 7 speed or so, from burning up in the air. Thats bassicaly whats been holding up the weapon technology. They've actually been able to build air craft carrier sized rail guns since about the mid 80's, but trying to keep the ammunition intact has been the hold up for this becoming a viable technology.

If what I hear through rumor control is right though, the Navy may be close to figguring that out, but I have no idea what speed or protectile sizes they are aiming for is.

vonmazur
2012-Jan-27, 09:12 PM
All I can say is, in WW 2, some inventor sold the Navy a Rail Gun. They bought it and tested it, and even put a pic in Poular Mechanics or a similar publication....Then it disappeared until the 60's when the idea came up again....now we know what the problem was--friction!!

The only Gatling types I am familiar with are the 5,56mm and 7,62mm models we used in Nam. For some strange reason, they never made a .50 cal version, I guess the 20mm covered that need...

Dale

BigDon
2012-Jan-27, 11:16 PM
Hey Dale what did yours sound like?

On the attack birds like the A-7 the 20mm chaingun was shorter barreled and sounded just like a one note fog horn.

The longer barreled 20 on the Tomcat sounded exactly like the zipper on a big wet canvas tent being pulled open a foot at a time on full length bursts and the short thirty round bursts sounded like a rifle shot drawn out a tenth of a second too long.

Actually Dale I wanted your opinion on the engineering challenges posed by the modern volley gun idea.

dgavin
2012-Jan-28, 12:54 AM
Dale:

.50 cal is not allowed to be used against people according to older geneva convention rules, it a silly hold over from WW2 days, but thats why they never made a chain gun version of the .50 cal.

vonmazur
2012-Jan-28, 01:48 AM
Don: The 7,62mm gun sounded like "BUUUUUURPPP"....the 5,56 model was about the same, not as loud. The major problem was reliable feed. When flying Gunships, I loaded the cans in the cabin myself. It had to be perfect...you can guess why; The ammo is in links, until it gets to the De-linker-Feeder, which was electric and synchronized with the gun itself. If the belts were not perfectly loaded, the motor would trip out the breaker....So much care was taken with this. I think this is a problem peculiar to the UH-1B/C/M, which was a cabin type chopper, the Cobra was designed with this in mind and did not have as much trouble as the C models did...(Airframe the same on the C/M models, just different engines, the B model was the same, but with the earlier rotor system, like the one on the D/H models. At sea level in the Delta, the B model barely got airborne, often we had to sort of slide off the ground effect and barely scrape the ground to get into translational lift.....)

There was a system that was even more fun, the nose mounted 40 mm, with the ammo in the cabin, feeding thru a Rube Goldberg chute, into the the center console, and around the radios to the turret...this one was fun to work on and keep free....When it worked it was really fine, they installed a computer to adjust for airspeed and deflection, finally!! When firing the 2.75" rockets, we used a grease pencil mark on the windscreen, the sight was just about worthless....

Dale

IsaacKuo
2012-Jan-28, 01:49 AM
I wish people would stop calling gatling guns "chain guns".

A chain gun is a completely different type of weapon, with a single barrel. A chain gun has a rotating and sliding bolt, similar to a bolt action rifle, but it is operated by a chain running around a rectangular path.

Delvo
2012-Jan-28, 01:52 AM
There are reasons why this kind of gun & ammo never got very big. Compared to a normal gun of the same size, they weigh more, kick back & shake more, are more trouble to maintain/repair, and generate more heat. Also, a larger one would be worse at handling the heat, and size is also an enemy of high rate of fire because of the greater inertia of the ammo & machine parts. And even if if the higher rate of fire were possible, you'd just use up ammo faster.

Just consider some of the known effects from guns that already have been used. Even at small sizes, they already had to invent the multi-barrel thing to avoid barrel overheating. At just 30mm, an A-10's gun creates more force from recoil than either of its engines can generate as thrust alone; although the two engines combined can make more, the throttle has to be tied in to the trigger so the engines rev up when firing and back down again when not firing, just to control the plane's speed. And back when ships carried big guns, they already carried the biggest ones they could support and still have the ship float and be steerable, firing would shake/rock the whole ship, and the length of time they could stay out and fighting before needing to get more supplies was determined by what they could carry with them all at one time.

Also, I'm not sure that bigger bullets would have the kind of effects on in-ground targets that you have in mind, even if it could be done. The usual targets of gatling guns are free-standing and/or hollow objects, and having some air behind the point of impact presumably affects how the target object reacts when hit.

IsaacKuo
2012-Jan-28, 01:53 AM
The Bofors Bandkanon self propelled gun fired fixed 155 mm ammunition from a replaceable 14 round magazine. Emptying the magazine took 45 seconds but few where built due to the enormous cost and they where taken out of service in 2003.
Interesting! I haven't heard of that one (I'm not very familiar with SPGs). I did a quick search on this weapon and didn't see any references describing the fixed ammunition. However, a YouTube video of it in operation clearly shows what must be a fixed ammunition mechanism, ejecting empty shell cases.

vonmazur
2012-Jan-28, 02:04 AM
Don: 3, 4 and even 5 or more barreled guns have been made in the past, the major problem is sight regulation, this is a major pain to do right. Your friend the gun maker can tell you all about this process. If the barrels are pefectly aligned, then one will shoot high and one low, due to being off center from the gun itself, like a double barreled shotgun, so the makers have to adjust the barrels to account for off set from center of mass...With 3 barrels, like the Germans make, the center barrel is usually under the two shot gun barrels, so not as big a problem, with double rifles like the English make so well, they take their time and have the manufacture down to a science, literally!! If the final finish was not a concern, it would be easier, but on a 30K double rifle, the customer expects perfection, so soft soldering the barrels and adjusting is done carefully, and since a hot blue process would melt the solder, they still rust blue the barrels. I have done rust bluing, takes a long time.....One has to get a good coating of the salt solution on the metal, let it rust or accelerate the process in a steam cabinet, then boil the metal parts in water, this changes the rust from Ferrous to Ferric Oxide (IIRC!!), then using an IRON bristle brush, you scratch off the rust, leaving a sort of gray blue finish, this is repeated-"tantum sufit", until the desired depth of blue is attained...I got tired of doing this so I just send the parts out to a local guy who does it for us....

So if you do not care about the 2k labor finish, just paint the darned thing with semi flat black BBQ Grill enamel!!

Dale

glappkaeft
2012-Jan-28, 03:24 AM
Dale:

.50 cal is not allowed to be used against people according to older geneva convention rules, it a silly hold over from WW2 days, but thats why they never made a chain gun version of the .50 cal.

That sentence contains nothing but untruths/myths.
* The .50 cal IS allowed to be used against people. The St Petersburg declaration from 1868 disallowed use of incendiary or explosive projectile less than 400 grams agains personel but says nothing about "ball" ammunition. The treaty is also considerd be obsolete in parts (e.g. use against/from vehicles and aircraft).
* The Geneva convention says nothing about what you can shoot people with, it's a treaty that "that establish the standards of international law for the humanitarian treatment of the victims of war".
* As Isaac said Chain gun != Gatling Gun (and while I'm at it != Revolver cannon)
* There exists both Gatling guns (e.g. GAU 19) and Chain guns (ATK Bushmaster) in .50 cal.

vonmazur
2012-Jan-28, 03:43 AM
Boy am I glad to see see this post Glappkaeft, now I will not have to, uh, explain things to some International Court in The Netherlands..:) The "Ma Deuce" was used by US Forces in Nam...("Ma Deuce"==M 2 Browning .50 Cal MG)

About the only thing that bothered me there was the NVA using Soviet 12,7mm guns, and most of the time we had 7,62mm...Hard to engage with the smaller lighter caliber, those Soviet guns....

Dale

Ara Pacis
2012-Jan-28, 10:15 AM
Ara, well for one, if you did build a naval unit along those lines, it would have everybodies attention. Much like the freakin' Deathstar. :OIt would look cool. :)


If I recall correctly the Iowa's sixteen inchers could penetrate 50 feet of granite with armor piercing rounds.I don't know about granite, but for reinforced concrete, the Mark 8 AP shell in plunging fire was expected to only penetrate up to 20ft deep, reaching depths of 27ft in a flat trajectory, and then the bursting charge was only 41lbs of Explosive D. link (http://www.navweaps.com/Weapons/WNUS_16-50_mk7.htm) So, even if you could get it deep, it wouldn't do too much damage. I think the BLU-113 can carry over 670lbs of explosive and also penetrates 20+ft of concrete and 100+ft of earth, officially - unofficially it's alleged to be significantly more.


So how deep would a stream of thirty to sixty similar projectiles arriving within 1.5 seconds go? Not a similtanious time on target attack as the round ahead should excavate a channel for the round behind it.I doubt a large channel would be excavated since we're talking about moving large volumes of earth against gravity. The point of using penetration to neutralize a bunker is not digging it out, but either piercing inside the envelope to explode in air or close enough that shock effects neutralize its capabilities (creating a camouflet (http://en.wikipedia.org/wiki/Camouflet) like the WWII Grand Slam "Earthquake" Bomb (http://en.wikipedia.org/wiki/Bunker_buster#United_Kingdom)).

Since a lot of modern bunkers are reported to use depth with one or more buried concrete roofs/shields between it and the surface, I recommend using the earthquake technique with a long, thin rod-from-god type bomb design (for penetration to 100-200+ft) with a robust, miniature nuclear charge (subkiloton yield).

dgavin
2012-Jan-28, 12:14 PM
That sentence contains nothing but untruths/myths.
* The .50 cal IS allowed to be used against people. The St Petersburg declaration from 1868 disallowed use of incendiary or explosive projectile less than 400 grams agains personel but says nothing about "ball" ammunition. The treaty is also considerd be obsolete in parts (e.g. use against/from vehicles and aircraft).
* The Geneva convention says nothing about what you can shoot people with, it's a treaty that "that establish the standards of international law for the humanitarian treatment of the victims of war".
* As Isaac said Chain gun != Gatling Gun (and while I'm at it != Revolver cannon)
* There exists both Gatling guns (e.g. GAU 19) and Chain guns (ATK Bushmaster) in .50 cal.

Hmm well they simply told us in the army not to use certain weapons on people in army becase of geneva convention, Back in the 80's. But then the army never was know to tell the whole story, much less pay attention to thier own rules. Guatanimo Bay violations are point in fact there. So it's not a case of untruths/myths. Just a case of bad training. Par for the course in army. Always had to figure out what they wern't telling you, or what was wrong.

This discussion prompted me to look up the history of the mingun's over all. Evidently Gatling also invented them first, back in the 1890's with a electic motor version of his gatling gun capable of 1300 round/pm even back then.

snowcelt
2012-Jan-28, 02:55 PM
Third attempt to post. First time to short. Second time was erased. I hope I hit the correct thingy. US never sighed the Geneva Convention; they only conformed. Us Canadians were not allowed to use shotguns. Americans were.

swampyankee
2012-Jan-28, 03:43 PM
The main issue with rail guns, or other fast ammo, is keeping the ammo once it's over mach 7 speed or so, from burning up in the air. Thats bassicaly whats been holding up the weapon technology. They've actually been able to build air craft carrier sized rail guns since about the mid 80's, but trying to keep the ammunition intact has been the hold up for this becoming a viable technology.


Have they dealt with the rather serious problem of wear of the rails?

Gsquare
2012-Jan-28, 04:11 PM
If I recall correctly the Iowa's sixteen inchers could penetrate 50 feet of granite with armor piercing rounds. So how deep would a stream of thirty to sixty similar projectiles arriving within 1.5 seconds go? Not a similtanious time on target attack as the round ahead should excavate a channel for the round behind it.

!

Obviously, bunker busting is a major concern....
Just in case you think the US military hasn't got that capability yet, I would like you to know we do and without having to redesign a whole new delivery system....(although the more the merrier as far as I'm concerned).

Like Dale has mentioned the idea is to penetrate far enough in before exploding the ordinance...
Just last year Boeing began delivery to the Air Force 35,000 lb bunker busters (called the GBU-57) Massive Ordinace Penetrator (MOP) able to crack through 60 feet of concrete. GPS guided drop bomb (far better than previous ones used against Saddam) that, if necessary, could drop repetitive ordinaces (from B-2 bombers).... Bet you can't guess who it was designed for ??

check it out: http://www.youtube.com/watch?v=BK2tUKDV9M8

and... http://www.youtube.com/watch?v=WlaIl9J14H4

Nothing beats good ol' explosives to get the job done. :))

G^2

IsaacKuo
2012-Jan-28, 04:50 PM
If you want to use an artillery gun for bunker busting, the best way is to drop it from a bomber (http://en.wikipedia.org/wiki/GBU-28).

HenrikOlsen
2012-Jan-28, 06:52 PM
At just 30mm, an A-10's gun creates more force from recoil than either of its engines can generate as thrust alone; although the two engines combined can make more, the throttle has to be tied in to the trigger so the engines rev up when firing and back down again when not firing, just to control the plane's speed.
That's actually a common misunderstanding made from combining two sets of info, the recoil and the engine being linked to the trigger.
The engine linkup is to prevent flame-out caused by the gun's almost oxygen free exhaust, additionally it lights the engine igniters for the duration of the burst to restart them if flame-out does occur.

The bursts are too short to significantly affect the speed.

Trakar
2012-Jan-28, 07:15 PM
Hmm well they simply told us in the army not to use certain weapons on people in army becase of geneva convention, Back in the 80's...

I take it this was given in the same training session where they told you that it was okay as long as you aimed at their helmets and web-gear, because those were considered "protective armour" and thus exempt from the non-personnel application restrictions?

LOL

Spetznaz paratroopers with wood files to extract access codes, drugs that didn't cure chemical agent exposure just made you not care about your injuries long enough to complete your mission, etc.,.

We need a good military myths and misunderstandings thread!

captain swoop
2012-Jan-28, 11:34 PM
Not allowed to carry Shotguns because of the Geneva Convention? Canada must have signed up to a different version to the UK. British Army has used Shotguns in the Jungle on 'Point' since WW2.

Trebuchet
2012-Jan-29, 12:59 AM
The shotgun reference may have been to WWI, when the US supplied them for use in trench fighting and the Germans complained. http://en.wikipedia.org/wiki/Winchester_Model_1897#World_War_I_Protests

Need I mention my preferred form of artillery has no need for chemical propellant at all?

dgavin
2012-Jan-29, 01:53 PM
I take it this was given in the same training session where they told you that it was okay as long as you aimed at their helmets and web-gear, because those were considered "protective armour" and thus exempt from the non-personnel application restrictions?

LOL

Spetznaz paratroopers with wood files to extract access codes, drugs that didn't cure chemical agent exposure just made you not care about your injuries long enough to complete your mission, etc.,.

We need a good military myths and misunderstandings thread!

Great stars man, that would get larger then the Conspiracy Theory Forum. The amount of tripe the military tries to foist off on people is just staggering to contemplate.

dgavin
2012-Jan-29, 01:58 PM
Have they dealt with the rather serious problem of wear of the rails?

Just know what I've seen on a few programs about it. Mostly the speed of the ammo being the biggest hurdle. Maybe some sort of carrige that wears out faster then the rails would?

dgavin
2012-Jan-29, 02:19 PM
Obviously, bunker busting is a major concern....
Just in case you think the US military hasn't got that capability yet, I would like you to know we do and without having to redesign a whole new delivery system....(although the more the merrier as far as I'm concerned).

Like Dale has mentioned the idea is to penetrate far enough in before exploding the ordinance...
Just last year Boeing began delivery to the Air Force 35,000 lb bunker busters (called the GBU-57) Massive Ordinace Penetrator (MOP) able to crack through 60 feet of concrete. GPS guided drop bomb (far better than previous ones used against Saddam) that, if necessary, could drop repetitive ordinaces (from B-2 bombers).... Bet you can't guess who it was designed for ??

check it out: http://www.youtube.com/watch?v=BK2tUKDV9M8

and... http://www.youtube.com/watch?v=WlaIl9J14H4

Nothing beats good ol' explosives to get the job done. :))

G^2

Thats an impressive bomb. Now if they could figure out how to make the tail section become a temporay plug for the bomb's entrance path, it would become even more effective in the the explosion would be containined inside the concrete itself, leading to even greater fracturing.

BigDon
2012-Jan-29, 02:33 PM
In WWI the Germans would *hang* troops caught using shotguns, from either side, they were that serious about it.

Ara, the thought excercise was to come come with a practical use for a massive vulcan-type weapon, not bunker busting per se. Preferably something it can do as well as an equally priced aircraft or better.

We just need a 15 billion dollar aircraft to compare it too.

If you're old enough you may recall the laser didn't have a use when it was first invented either. For years actually. It was merely a "can we do it?" (i.e. create coherent light) kind of invention. Then we found uses for it.

For the longest time the main users of lasers were baby bottle manufactueres who used them to pierce the rubber nipples at speed.

What would you use a eight to sixteen inch Vulcan for if not bunker busting?

How do you feel about a non jammable, doesn't care if your invisble air defense? Then you go from armor piercing to HE/Frag rounds.

With the right sensors I guess you could keep the air space over your city free of tresspassers. (Reindeer and such.)

Though you own troops might have some issue if you were trying to chase down some pesky nape of the Earth flying target.

Antice
2012-Jan-29, 04:44 PM
With the right sensors I guess you could keep the air space over your city free of tresspassers. (Reindeer and such.)


Yes. those pesky flying reindeer and their turds dropping down without warning every x-mas. :whistle:
155mm auto-howitzers sure fit that job splendidly. :D
where can i buy one?

HenrikOlsen
2012-Jan-29, 05:08 PM
How do you feel about a non jammable, doesn't care if your invisble air defense? Then you go from armor piercing to HE/Frag rounds.
I have quite a liking for the Dutch Goalkeeper CWIS, which uses a shortened version of the GAU-8/A aka the holycrapitspointedatus to throw incredible amounts of heavy nastiness at flying targets. It'll take out an SS-N-22 Sunburn going at mach 2 in 5.5 seconds from detection to kill.

dgavin
2012-Jan-29, 05:50 PM
Found a video of the Test firing of the navy's rail gun. All the flame from the firing of this is due to the projectile and it's carridge hitting the atmosphere and starting to burn (and thats just at mach 5). None of it's from chemical explosives at all.

http://www.military.com/video/guns/naval-guns/railgun-update-from-general-atomics/904431955001/

It looks like the rounds are only at mach 5-7 right now. But thats giving them 7km parallel to ground flight after punching through a target even. Kind of impressive.

Imagine one of those coming at you at say 25 times the speed of sound.... OUCH.

JCoyote
2012-Jan-29, 05:51 PM
On rotary large caliber cannons...

The major issue here is trying to rotate something like that. The mass issues have already been mentioned. But let's be honest, what do you think a battleship with nine 16 inch guns is?

Also there seems to be an idea that a rotary cannon somehow magically sends all its shells into the same aim point. They don't. Not even close! For example the .50 BMG GAU-19 is rated at an 80% circle of 5 milliradians. This means that at 100 yards, a football field distance that is within point blank range for the weapon, 8 out of 10 bullets will land within an 18" diameter circle. That's a foot and a half. Increases in caliber also introduce issues that decrease the inherent accuracy of the system and broaden those areas. Contrast this with a semi-automatic .50 BMG rifle that puts 3 out of 3 bullets in a 2 inch diameter circle (or better) at 100 yards. Only the vast quantity of fire of rotary guns makes them "accurate", but they are about area saturation like a shotgun, not drilling holes.

At the 16 inch range, and even the 155 mm range, the decision to fire is actually sometimes a fiscal one. Large battleship guns the cost of ammunition and the wear on the barrels it entails are part of the decision-making process to employ them. There is a matter of human scaling going on here. Rotary cannons at small scales are easier to coordinate than trying to get many people to fire slower weapons on the same target area. But at larger scales where individual barrels require multiple persons to crew them it becomes easier to try to coordinate the crews (since they require crew-coordination to fire even 1 round) than physically manage exponentially larger guns for the caliber. Also, the cost density is a lot higher if you invested that much in a giant rotary gun. A single assault could remove the giant rotary cannon with higher likelihood than a single assault taking out all 9 guns on a battleship. Improved targeting systems are a better and cheaper investment.

A current battleship is MORE likely to land 9 shells on target in a second than any potential rotary 16 inch gun could. The smarter investment is better targeting and intercommunication systems for the guns than trying to spin them up.

The reason automatic fire is considered to have effectiveness against personal armor isn't necessarily that bullets would land on top of each other but that armor isn't designed to handle an infinite number of impacts and deteriorates with every shot. Automatic fire is simply compensating for body armor by wearing it out in a single exchange. The soft components of current body armor won't stop spitzer bullets at reasonable velocities, the hard components have to do that and every shot stresses and damages that plate... and the plate is supposed to get damaged with every round it stops... so that you aren't damaged.

The same applies to the A-10 and tank armor. Tank designers have to make decisions on where to put mass. As a tank is a weapon for attacking, the front is where most of it goes as it will do the most good in the intended role. The sides are weaker. The back and top are weakest. The firing rate of the Avenger is less about trying to drill through armor than to make up for the speed of a moving aircraft with saturating the target to insure a decent number hit the target.

Already mentioned are the barrel supports and other things, but what about the sort of turret required? That also could get ridiculous.

But maybe for an alien race that were many times larger than humans it might be practical...

Gsquare
2012-Jan-30, 03:30 AM
Responding to previous posts....

The A-10 gatling gun acts as a 'brake' on the A-10; the pilot feels the negative g, but as HenrikOlsen says, the brevity of the burst keeps a lid on speed reduction.

Just for fun, ignoring the linkage issue, lets do a back of envelope calculation to see what sort of recoil the pilot gets.... since Delvo brought it up:

Using Armor Piercing Incendiary projectiles (15 oz. weight) and a firng rate set at the higher end - 4200 / min.- and a 1100 m/sec muzzel velocity (some stats show a lower 975m/sec, but I think 1100 is more accurate).... He's unloading about 29.5 kg. per sec.
So I get about 32,450 Newtons of 'negative thrust' during firing. Check my results just to make sure. {Using T = (dm/dt)v }

Now the approx. 9000 lbs of thrust per engine gives a total max. forward thrust of about 80,100 newtons .
Comparing that to the neg. recoil of 32,450 Nt. we see it is not insignificant..... placing neg.(recoil) thrust about 40% of the total engine thrust. However, as Henrick said, its the shortness (1 to 2 sec.) of the burst that saves the day.

Lets see what sort of deceleration the pilot feels:
Assuming no ordinance (only ammo) we can use a gross weight of about 15,000 kg. and the above recoil data,..I get about 2.15 m./sec^2 of neg. acceleration WHILE he is on the trigger. (That's between 1/4th and 1/5 g...actually, its .22g)

This is sort of like doing 60 mph in your auto on the freeway and pressing on the brakes for 2 seconds; you feel the negative g but you don't slow down much.

However, lets say we have a trigger happy pilot and he does a full 10 second blast (I know I'd try it just to satisfy the 'test pilot' in me :)) )...he gets slowed by 71 ft/sec.
The % decrease in velocity of the A-10 will be dependent upon his initial velocity.....
If he is doing about 350 mph (and somewhat level), he gets a reduction in speed of about 14 %.
For a lower speed he gets a greater reduction... 250 mph and he gets reduced by almost 20% for a 10 second blast. Higher speed reduces less. (I'm ignoring the minor reduction in weight due to the fact that he unloaded almost 700 lbs. on the target)....

Anyway, just a figuring....check my numbers if you like. ;))

G^2

Gsquare
2012-Jan-30, 04:11 AM
Thats an impressive bomb. Now if they could figure out how to make the tail section become a temporay plug for the bomb's entrance path, it would become even more effective in the the explosion would be containined inside the concrete itself, leading to even greater fracturing.

Yea, well, that's an idea...

The thing that I find appealing about this type of Bunker Buster (besides the loud bang :)) ) is the fact that it requires no propulsion except gravity itself. Its the ultimate gravity assist bomb. I think the terminal velocity gets beyond mach 1 .... or at least it could easily be designed to get up to Mach 3 if dropped above 40,000 feet height. (ya get a sonic boom AFTER the explosion).

Tall Boy was a biggie bult in WW2 and was almost aerodynamically perfect enough to reach mach 3 from 40,000 feet, (but they couldn't drop from that high). .http://en.wikipedia.org/wiki/Tallboy_(bomb)

The Boeing boys could do it with the MOP had they wanted. Gravity solves a lot of propulsion problems in trying to bust through into a hell hole. Just grease up the nozzel... and let gravity do its thing. Yea Gravity ! :))
I think the problem is that when you are trying to get deep PENETRATION, there may be a limiting Mach number before you end up crushing the nose, the casing, or the innerds of the bomb to the point of not being able to preserve the integrity of the delayed response....although I'm not quite sure about that. Probably some damage trade offs with increasing drop velocity.



Found a video of the Test firing of the navy's rail gun. All the flame from the firing of this is due to the projectile and it's carridge hitting the atmosphere and starting to burn (and thats just at mach 5). None of it's from chemical explosives at all.

http://www.military.com/video/guns/n.../904431955001/


I couldn't get your rail gun link to work. Is it just me?

G^2

redshifter
2012-Jan-30, 04:45 AM
When I was in the military, we used to say that if we were attacked and used a .50 cal to take out personnel, we'd just say we were aiming for their helmets; after all a .50 can be used to destroy equipment. I was in a feild artillery unit on a 155mm cannon. The biggest land based artillery was the 8 inch guns. A 16 inch gatling gun would have serious weight issues. A 16" tube probably weighs 10 tons at least. The 155mm tube on the guns I fired was a good 4 tons.

The 20mm gatling guns for ground based air defense were referred to as 'burp guns' as someone alluded to already. Sounded just like one too. The Vietnam vets in my unit said they used the 20mm gatling guns to clear landing zones.

Tensor
2012-Jan-30, 05:47 AM
When I was in the military, we used to say that if we were attacked and used a .50 cal to take out personnel, we'd just say we were aiming for their helmets; after all a .50 can be used to destroy equipment. I was in a feild artillery unit on a 155mm cannon. The biggest land based artillery was the 8 inch guns.

You don't mean the biggest ever, do you? The US (WWII) and Britain (1854) both had 914 mm (36 inch) siege mortars. Neither were actually fired in combat and the US mortar was actually modified to be a siege mortar. Germany, during WWII, had the Schwerer Gustav, an 800 mm (31 inch) railway gun that was used on the Eastern Front, during the siege of Sevastopol (fired a seven ton shell, 23 miles). Wikipedia list 10 guns or mortars (non-naval, explosive shell) that are larger than 16 inches. Germany had a 600 mm (24 inch) SELF-PROPELLED siege mortar during WWII, although at 6 miles per hour, self-propelled may be almost exaggerating. It was primarily moved by rail.


A 16 inch gatling gun would have serious weight issues. A 16" tube probably weighs 10 tons at least.

At least. As mentioned earlier, the 16"/50 Mark 7 was ~119 tons with just the tube and ~133 tons with breech.

BigDon
2012-Jan-30, 12:27 PM
VonMazer, I wouldn't need that level of engineering, where all barrels had the same aim point. The one I saw as a youth made a circle five inchs in diameter at 100 yds. A direct fire shotgun as it were. A reproduction of a Nockgun, a smoothbore muzzle loader.

I was thinking of a meant to just fire forward, break open, rifled version. So you could do that at 300 to 500 yards AND use a speed loader, though a cylinder comes to mind as well. Would a cylinder be less of an engineering challenge than a break open, or vise versa?

Mr. Coyote has a point, (and unlike mine, isn't on top of his head), first, I don't think I've ever said "welcome to the forum", so welcome to the forum, and two, spinning five, 100 ton cannon barrels does sound like a bit much. Though my carrier had four twenty ton propellers, that were attached to shafts that weighed close to 100 tons, the mission isn't to make cannon as expensive as possible.

So that means the barrels stay stationary and the breach would have to rotate. Probably within the circle of barrels.

Putting it on a ship with those stablizers, like those North sea oil rigs have would obviate the need for a traditional turret. And you could use compartment flooding to elevate and depress the barrels! Keep the good ideas coming J!

Note to self: J gets to fire the first burst.

dgavin
2012-Jan-30, 03:14 PM
I couldn't get your rail gun link to work. Is it just me?

G^2

Trying to post it again here, wasn't working for me either.

http://www.military.com/video/guns/naval-guns/railgun-update-from-general-atomics/904431955001/

redshifter
2012-Jan-30, 07:42 PM
[QUOTE=Tensor;1984896]You don't mean the biggest ever, do you? QUOTE]

I should have been more specific. I meant the largest caliber US Army land based artillery piece deployed and in use as of 1985.

Ara Pacis
2012-Feb-02, 08:23 AM
Ara, the thought excercise was to come come with a practical use for a massive vulcan-type weapon, not bunker busting per se. Preferably something it can do as well as an equally priced aircraft or better.That's my point, bunker-busting probably isn't that mission, since 16" AP rounds don't penetrate deep enough or carry enough explosive to damage deep bunkers.


If you're old enough you may recall the laser didn't have a use when it was first invented either. For years actually. It was merely a "can we do it?" (i.e. create coherent light) kind of invention. Then we found uses for it.IDK, the idea of the death ray had been around for decades if not centuries. Light had already been used for signals and even recording audio tracks on film. Same with RADAR.


What would you use a eight to sixteen inch Vulcan for if not bunker busting?

How do you feel about a non jammable, doesn't care if your invisble air defense? Then you go from armor piercing to HE/Frag rounds.

With the right sensors I guess you could keep the air space over your city free of tresspassers. (Reindeer and such.)

Though you own troops might have some issue if you were trying to chase down some pesky nape of the Earth flying target.I was thinking air-defense, as well as saturation bombardment, like they already can do.

Ara Pacis
2012-Feb-02, 08:26 AM
Speaking of gatling guns, I was thinking that a solution to rail-gun rails degrading was to use two gatling-like rail carriages. They both rotate between shots so the new round has new/cleaned rails. Depending on the degradation, they used rails may be refurbed between shots for multiple uses before needing to be removed from the carriage rotation.