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Artillery Discussion Thread

The Military Issues & History Forum is a venue to discuss issues relating to the military aspects of the Indian Armed Forces, whether the past, present or future. We request members to kindly stay within the mandate of this forum and keep their exchanges of views, on a civilised level, however vehemently any disagreement may be felt. All feedback regarding forum usage may be sent to the moderators using the Feedback Form or by clicking the Report Post Icon in any objectionable post for proper action. Please note that the views expressed by the Members and Moderators on these discussion boards are that of the individuals only and do not reflect the official policy or view of the Bharat-Rakshak.com Website. Copyright Violation is strictly prohibited and may result in revocation of your posting rights - please read the FAQ for full details. Users must also abide by the Forum Guidelines at all times.
Manish_P
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Re: Artillery Discussion Thread

Postby Manish_P » 23 Jul 2017 21:14

Please specify what are the 'pre determined specifications and milestones' and how are they determined

Also please elaborate on the precautions which need to be taken and whether all the precautions taken during the trials will still eliminate the risk/chance of faulty ammunition being sent to the frontline units.

chetak wrote:
abhik wrote:How do you prove an "unproven" gun if you don't use it the way it is meant to be used?


The new gun has to meet all pre determined specifications and milestones and the results have to be analysed and certified as having met expectations.

Only after all this will it be accepted into service. until then the firing trials (especially) are to be treated as dangerous and risky and precautions have to be taken.

A burst barrel can be lethal to people standing closeby.

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Re: Artillery Discussion Thread

Postby Manish_P » 23 Jul 2017 21:21

That's true, sir.

But please check the effect of a 155mm round going off a few feet/mtrs in the air.

Or even on the ground (you can check the videos of 155mm IEDs in Iraq)

Even a EOD bomb suit will not give guaranteed protection


shaun wrote:was going through the comments and videos posted , well , Dhanush does have automation but ppl needs to be near for running it. A layer sits on the left hand side of the gun, operating the fire control computer and driving the howitzer when in self-deployment mode. Even CAESAR and ATMOS have crew near to their gun. What I find lacking is personal protective gear with our boys wearing caps.The injuries could have been minimised with better PPE but alas its the same like our infantry , isn't it.

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Re: Artillery Discussion Thread

Postby abhik » 23 Jul 2017 21:29

BTW how many 155mm guns does the IA have currently? Only around 200 of the original 400 bofors guns were said to be operational, did they manage to salvage any of the rest? Also how many M46 were upgunned.
90K rounds manufactured per year does not sound like a lot, If we have say 450 guns, it's just 200 rounds per gun per year.

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Re: Artillery Discussion Thread

Postby Manish_P » 23 Jul 2017 21:43

So many wise words in this one post by Shiv Ji (i have edited it to keep the ones i want to refer to).

I also hope that heated, off-the-cuff, ranting posts do not make this forum lose valuable, knowledgeable posters like Rohitvats, Tsarkar, Deejay and others from the services and Hari Nair, Raghuk from the institutions.

I think soldiers need to be given space to speak and for us to listen


To me, this one single sentence encapsulates what BRF should stand for

shiv wrote:This is the difference between information and knowledge, but BRFites outside of the armed forces do not understand.

Most desis have zero experience of holding a weapon let alone shooting a firearm and it is deadly powerful stuff - that can put one's own life in danger from various issues ranging from mishandling to component failure. And this is at peacetime when no one is shooting at them.

Flying itself is unnatural and flying up in a 5 ton metal box is definitely more risky than going to office every day.

On the other hand we have forum strategic thinkers who tell us "Oh 105 mm is not enough for Himalayas. We need 155 mm" and so on. We see these weapons as toys that will kill Pakis and Chinese and do not even think for a millisecond that an artillery shell is a bomb that is thrown forward by another bomb. One bomb (the propellant) goes off within a few meters of the faces of men who are operating the cannon and the other bomb is supposed to fly off tens of kilometers and burst under a paki's ass. Great fun. No one on BRF stops to think about the risk of bomb no 2 (the artillery projectile) going off a few meters away. Only people who have operated this stuff or have seen it from close by can see how dangerous this equipment is even when handled well and with no failures and how these people are actually putting their lives on line every day - peacetime or wartime. They just don't talk about it.

So by and large we are a bunch of ignoramuses and operate under the excuse that "We are here to learn". Fine. Let us all learn - but no one is going to learn anything by contempt for the people whose job we want to learn about. I think soldiers need to be given space to speak and for us to listen. The media are idiots, no better than us. Anyhow - I am hoping to see some positive changes in BRF.

shaun
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Re: Artillery Discussion Thread

Postby shaun » 23 Jul 2017 22:17

Manish_P wrote:That's true, sir.

But please check the effect of a 155mm round going off a few feet/mtrs in the air.

Or even on the ground (you can check the videos of 155mm IEDs in Iraq)

Even a EOD bomb suit will not give guaranteed protection


shaun wrote:was going through the comments and videos posted , well , Dhanush does have automation but ppl needs to be near for running it. A layer sits on the left hand side of the gun, operating the fire control computer and driving the howitzer when in self-deployment mode. Even CAESAR and ATMOS have crew near to their gun. What I find lacking is personal protective gear with our boys wearing caps.The injuries could have been minimised with better PPE but alas its the same like our infantry , isn't it.


PPE including ear muffler and ballistic helmets are basic protections not luxury and just like our infantry, we tend to ignore it. I have told all along , big ticket inductions of systems is necessary but the men running those systems needs the highest level of protection , be it armoured carrier , light weight helmets and body armour , comm gear etc.

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Re: Artillery Discussion Thread

Postby ramana » 23 Jul 2017 22:22

GCF, OFB Jabalpur, pored over 12,500 documents from Bofors to develop this Dhanush gun. They added more improvements to that design. And lessons learned from the SOLTAM upgrade. They test fired 2000 rounds before handing over for user trials.
Those are the specifications that were met.

There are two issues. The May 2017 issue was due to the fuze activating at short distance from the muzzle.

The July Shell hitting muzzle brake is due to side-slap.
Happens rarely. Looks like it happened in SOLTAM upgrade also.

If one notes the small print the muzzle bore for Dhanush is larger than the SOLTAM upgrade barrel.
If one wants to eliminate effect of side-slap then barrel has to be short or barrel erosion limits have to be tightened to reduce clearance. Taht is barrel life restricted. As GCF makes the barrels this is not a problem.

In many militaries disposal of aging ordnance is a major problem.
One solution is to use it up in tests and demonstrations.
This is where the bug bites.
Sometimes very publicly.

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Re: Artillery Discussion Thread

Postby ramana » 23 Jul 2017 22:23

shaun et al can we have a list of standard PPE used in NATO and FSU countries in artillery troops.

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 02:21

Xxxx
Ramana wrote in artillery thread

"one notes the small print the muzzle bore for Dhanush is larger than the SOLTAM upgrade barrel.
If one wants to eliminate effect of side-slap then barrel has to be short or barrel erosion limits have to be tightened to reduce clearance. Taht is barrel life restricted. As GCF makes the barrels this is not a problem."

If after a n number of shell firing the gun can be pulled into EME workshops and

1) rebore to a slightly bigger size and have appropriate shell dia

2) fit piston rings like on the shell to accommodate the over size bore

Of course the bore has to be machined to the largest dia after erosion or make the e eccentricity equal in the length of the bore

Or cut and weld and heat shrink that part of the barrel with new piece?

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 02:23

It's not simple like that. Re machining causes other problems. The barrel bore is always larger than the shell diameter or won't fit. Shell has a driving band of copper at the base to provide tight fit for gasses to push the shell out of the barrel. The barrel is coated with chromium to give low friction surface. All this wears out and barrel has a finite life. US 175mm guns were rated for 2000 rounds for barrel erosion. In Vietnam the barrels shattered not just cracked after 425 firings. The investigation repeated the conclusions and a huge inventory was benched. However the investigation led to better understand how thick pressure vessels work for repeated loadings.
As GCF makes the barrels just order more barrels. It's not import.

Of the 415 Bofor guns that were purchased in 1980s about 200 only are there. I think it's barrel erosion. Let's ask around. Or better do the digging ourselves.

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Re: Artillery Discussion Thread

Postby Karan M » 24 Jul 2017 02:43

deejay wrote:... and for some TFTA action - Here is the Dhanush itself



As you can see this is under testing. You judge the distances.


This video tells me the crew is testing the Dhanush in real world conditions and hence no long length cable from far away is being used... hence niran's post about mass casualties is very plausible.. i would presume given how closely packed the guns are, crews from several guns were injured.

I applaud your optimism deejay sir.. but seriously, expecting OFB to rectify this & its ammo QA is hoping for the impossible. Any other DPSU, including HAL, one can expect rectification. OFB .. you were asking me why I was so cynical about their 7.62mm gun.. this is why.
Their "expansion" of the Bofors to this Dhanush variant.. I am not sure as to how much core R&D went into this as versus rough thumb rules.
ADRDE at least for ATAGS would have done everything from basics.

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 03:35

I think we should let the true root cause for the May and July incidents be competed.
They did come to the root cause of the early barrel burst.

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 03:55

From the ScribD linked by tsarkar

The M572 PD does have limitations. It is not watertight and is not drop safe. Prematures have occurred when the weapon is fired at high muzzle velocities from longer-barrelled weapons. These factors led the South African company Naschem, a division of Rheinmetall Denel (Pty) Ltd, to develop the essentially similar, but upgraded M841 PD fuze with some additional components. These components can be retrofitted to existing M572 PD fuzes. The M841 PD can be used with projectiles fitted with Base-Bleed (BB) units and weighs 770 g.


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Re: Artillery Discussion Thread

Postby pandyan » 24 Jul 2017 04:40

Excellent talk by Col Lalit Rai and great background on history, people, topography of Jammu & Kashmir. Watched this for the first time.
Colonel Lalit Rai’s sterling account of the role played by his battalion in the icy heights of Khalubar, coupled with first hand accounts of daring, death and triumph moved the 1200+ audience to tears. It was particularly poignant that General Thimayya had 50 years earlier in 1949 played an equally stellar role in Kargil.

Posting here because of relevance to recent discussions on hardship (With examples) faced by armed forces. His speech starts around 38 minutes.

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Re: Artillery Discussion Thread

Postby niran » 24 Jul 2017 06:54

ramana wrote:shaun et al can we have a list of standard PPE used in NATO and FSU countries in artillery troops.

-Helmets which every soldiers have
-Ear plugs rubber one preferred over silicon one WRT to maintenance like plain water wash.
- Ear muffs for commander (Commander needs to communicate both orally and through radio thus radio equipment forces him to use mufflers) why? muffs there are ear plug radio equip? coz communicating orally to team necessitates taking off the the ear peace ear plugs are pain in the arse to do so.
BTW ear plugs reduces 80% noise if used properly i.e. squish the plug between your thumb and index finger of hand corresponding to the ear(most important) use the other side hand to pull the ear up and away form the head, push in the squished plug.see it takes at least 46 seconds for a trained ones.
these are the PPE for arty all over the world, khan people have those 3M googles too, but have never seen it with others.

WRT trails:
initial trails is done the current trails re user trails e.g. @chetak co. ltd. manufactured a tablet(arty gun) his intial trail would be will the tab boot up on from power button or will it blow off or the buttons fall off with few presses. that stage with Dhanush is done.
current trails are user trail such how quick is goole map(arty shell). how good does the tab (Dhanush) render BRF site(Arty shell)

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 07:33

Not so fast.
Yusuf as you seem to have a hang of it a few questions:

1) In the first shell burst in the barrel attributed to age (12years old shell) and air bubbles in the shell, what was the charge used? Maximum? Was the fuze recovered? What was its condition?

2) In recent May 2017 shell functioning out side the muzzle, Was the debris collected? By any chance what was the charge and again was the fuze recovered? And did it function?

3) In the recent July 2017 trials what was the charge and did the shell function?

Thanks if any one can get this information.

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Re: Artillery Discussion Thread

Postby Singha » 24 Jul 2017 08:42

the atags will be perhaps the first army howitzer in world with a 25 liter chamber unless the pzh2000 and denel G6 has it.
naval cannons however have been 55cal for a while incl all the USN ships.

we got to be careful about considering every aspect of this on the atags.

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Re: Artillery Discussion Thread

Postby shaun » 24 Jul 2017 09:25

ramana wrote:shaun et al can we have a list of standard PPE used in NATO and FSU countries in artillery troops.

:shock: Pretty exhaustive eh.. .!!!...NATO have different armies with various equipment , apart from what Nirav ji have told , i will surely dig in to it.

Please id the below image and whether its still in use.
Image

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Re: Artillery Discussion Thread

Postby JayS » 24 Jul 2017 10:43

Re using conservative SOP for trials:

Folks lets not forget that Dhanush has been through all the pre and post design freeze trials. Dhanush is practically inducted now. Yes on paper status may not be so, but if the gun was not "proven", I highly doubt IA would have moved ahead with "user exploitation". These recent trials are part of "user exploitation" which by definition means the user will use it in a way the gun is supposed to be used in daily operation to see how it works and to develop SOPs. And in daily ops there are 4-5 men always very near to the gun i.e. in the danger zone. Clearly the particular flaw is seen only in a special situation (can't say which since we do not know the test particulars). If it was a systematic design issue, it would have shown up previously under the prototype trials.

Lets assume that the particular issue crops up only under high rate of firing and after certain rounds are fired in continuation (like a gun would fire in an intense war). Had IA opted for a conservative SOP where the gun crew would clear the danger zone every time and move away say 50mtrs after loading every round, would the gun ever achieve the kind of fire rate that would have triggered the failure..? of coarse not, because every loading and firing would take more time now. If not in these trials, it would have cropped up in normal operations or some exercise. The purpose of the 'user exploitation' trials is precisely to push he gun to its intended envelop limits under the regular working environment and see if its performing flawlessly in certified operational envelop. Thus the arguments that the IA crew should have opted for more precautionary approach of gun firing is valid for such trials. For prototype testing its a different matter.

Also regarding the use of good ammunition - I suppose while this is a valid point for prototype testing, again IMO, for user trials this is not a valid argument. Because clearly there is a flaw somewhere in the system - in logistics of the ammunition and how its stored/used up, or with the ammunition itself i.e. failure within certified shelf-life, or with the gun operating SOP. If it wasn't for this instance it would crop up somewhere else. Rather IA should focus on finding out the flaw and removing it. Because Dhanush would be firing older ammo in real life all the time. These trials are there to precisely test such real life scenarios. In user exploitation trials there is a better chance to catch such flaws than under normal operations.

I hope OFB can come up with design mod to remove this issue. In case its not possible for some reason, I think IA will come up with some SOP where the issue will be tried to deal with, may be prescribing operating limits such as max number or rounds fired with certain rate or max rate of fire for certain number of rounds, how much time to allow cooling of barrel so on and so forth. That's how it should be IMO.


Deejay/AK saar,

Apologies. Clearly we need to be more sensitized about the harsh working environments that our soldiers have to endure. But let me state it that this is not out of sheer ignorance or carelessness for soldiers' well beings. I was the one who posted about these instances here first. The way tweets came and the articles later, they implied that there were no major injuries or casualties. That's the reason why perhaps the aam abduls like me failed to think about the possibility of injuries. Its perplexing to me why no one in media reported the injuries. Or may be IA did not release the details..? I don't know. But I can assure this was definitely not out of sheer ignorance or carelessness. Yes, may be lack of knowledge. We need to improve on that. Hope we will, given inputs are coming from folks like you who have first-hand experience from the field.

Re supplying proper safety gears for IA gunner - I think we lack severely in this one. I remember to have read a report saying that majority of Gunners suffer acute hearing loss of various degrees and some of them go nearly deaf. This issue is very serious and IA/GOI should think/do more on how to reduce the damage caused due to extended exposure to loud bangs. I don't know of any DRDO study or product directed in this direction. May be they have one, I am not aware of. If they don't DRDO/CSIR should be directed do undertake one.
Last edited by JayS on 24 Jul 2017 19:53, edited 1 time in total.

Jaeger
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Re: Artillery Discussion Thread

Postby Jaeger » 24 Jul 2017 13:32

shaun wrote:Please id the below image and whether its still in use.
Image


I think it's a 25-pounder or possibly a Yugoslav 76mm Mountain Howitzer.

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Re: Artillery Discussion Thread

Postby Gyan » 24 Jul 2017 13:47

There are two facts of every story:-

Barrel

For instance, INSAS LMG barrel had always been problematic and production was stopped around 2002 and after solving the problem, LMG production was restarted around 2012.

Fake problems

INSAS carbine was criticized/never inducted for not being able to fire INSAS INDIAN ROUND as there was lot of flash, sound and recoil. But the issue was with the design of propellant as it was "slower" burning; the requirement to fire special Indian rounds has been dropped for proposed import of Carbines (as the requirement to fire Indian round through short barrel was physically impossible). So why did INSAS carbine faced vilification for so long?

Conclusion

There is a huge lobby against Dhanush, lets see what happens.
Last edited by Gyan on 24 Jul 2017 19:07, edited 1 time in total.

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Re: Artillery Discussion Thread

Postby shaun » 24 Jul 2017 17:08

Jaeger wrote:I think it's a 25-pounder or possibly a Yugoslav 76mm Mountain Howitzer.


Must be 25 - Pounder but is it still in use.

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Re: Artillery Discussion Thread

Postby ks_sachin » 24 Jul 2017 19:26

Gyan wrote:
[

There is a huge lobby against Dhanush, lets see what happens.


What planet do you inhabit? Have you even read what has been penned in the preceding posts?

11 men have been seriously injured testing a gun being inducted and you make these asinine statements!

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Re: Artillery Discussion Thread

Postby suryag » 24 Jul 2017 19:55

Gyan ji is flame baiting here

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Re: Artillery Discussion Thread

Postby Gyan » 24 Jul 2017 19:56

Deleted
Last edited by Gyan on 24 Jul 2017 20:04, edited 1 time in total.

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Re: Artillery Discussion Thread

Postby abhik » 24 Jul 2017 19:59

Singha wrote:the atags will be perhaps the first army howitzer in world with a 25 liter chamber unless the pzh2000 and denel G6 has it.
naval cannons however have been 55cal for a while incl all the USN ships.

we got to be careful about considering every aspect of this on the atags.

IIRC ATAGS has 27 liter chamber.

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 20:11

shaun wrote:
ramana wrote:shaun et al can we have a list of standard PPE used in NATO and FSU countries in artillery troops.

:shock: Pretty exhaustive eh.. .!!!...NATO have different armies with various equipment , apart from what Nirav ji have told , i will surely dig in to it.

Please id the below image and whether its still in use.
Image

From Sanjay

On the artillery thread - could you educate posters that the gun most recently posted was a 75/24 pack howitzer that was used in the direct fire role during Kargil.

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Re: Artillery Discussion Thread

Postby Singha » 24 Jul 2017 20:51

daish sp cannon in vicinity of DEZ..looking at the long string used to trigger it, the piece is in shaky state so taking no chances which direction it will fire - front or back. they smear mud and sand on vehicles to hide from air recon.

Image

another type of daish piece - looks like a bmp cannon? on a more sturdy tipper truck whose flatbed is very strong.
Image

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Re: Artillery Discussion Thread

Postby abhik » 24 Jul 2017 21:18


ramana
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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 22:13

Marten wrote:Can anyone share the shrapnel (airburst) radius? Unnamed sources claim 100m for 155. Is this correct?


Marten, Excellent question.

When the shell bursts most of the fragments will be from the cylindrical portion. The nose tip and the base would come off as one piece due to their stiffness.
There is a Canadian artillery presentation of the lethality of the shell fragments as function of distance will try to locate. Meantime you can Google too! Use key words: shell fragments super quick and 155 mm.

Airburst shells are different as they have small spherical pellets held together in wax or epoxy. US calls them beehive from the buzz of the pellets whizzing by. These have a proximity fuze and bursting charge along the middle.

In Angola, the South Africans found most Western ordnance developed for fighting in Europe is useless as the shell fragments are too large and hence lose velocity. So they came up with these pellet loaded shells and even 250 kg bombs.
SOP was one regular shell with delay fuze to burst a shelter followed by a pellet shell.


Google For
The Last Cold War Battle: Angola"

ramana
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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 22:18

negi wrote:^ Side slap can cause a shell to go off if the fuze is armed and is designed to go off on impact (be it head on or grazing impact); of course all depends on how violent the side slap is i.w what is impulse which the shell experiences when decelerating within the barrel due to the side slap, however in this case side slap was not the only event that occurred as per reports shell did hit the muzzle break so if the impact was much closer to a head on impact shell would go off.


I am still studying accounts from WWII onwards and will report back.
Side-slap could result in loads up to 40,000 gs lateral.

In the barrel it is accelerating!!!

There is detonation initiation chain from the nose area which occurs only if the fuze is activated.
The side-slap acceleration could be enough to set off the explosives from the shock.
If so the broken nose would be found in debris and not initiated.

That's why all those questions.

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 22:19

Those truck mounted guns don't have stiffness and hence accuracy could be an issue.

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Re: Artillery Discussion Thread

Postby Lisa » 24 Jul 2017 22:32

ramana wrote:
Marten wrote:Can anyone share the shrapnel (airburst) radius? Unnamed sources claim 100m for 155. Is this correct?


Marten, Excellent question.

When the shell bursts most of the fragments will be from the cylindrical portion. The nose tip and the base would come off as one piece due to their stiffness.
There is a Canadian artillery presentation of the lethality of the shell fragments as function of distance will try to locate. Meantime you can Google too! Use key words: shell fragments super quick and 155 mm.

Airburst shells are different as they have small spherical pellets held together in wax or epoxy. US calls them beehive from the buzz of the pellets whizzing by. These have a proximity fuze and bursting charge along the middle.

In Angola, the South Africans found most Western ordnance developed for fighting in Europe is useless as the shell fragments are too large and hence lose velocity. So they came up with these pellet loaded shells and even 250 kg bombs.
SOP was one regular shell with delay fuze to burst a shelter followed by a pellet shell.

Google For
The Last Cold War Battle: Angola"



I may be wrong but I always thought Beehive referred to fléchette rounds, eg,

https://en.wikipedia.org/wiki/Beehive_a ... nnel_round

and

https://en.wikipedia.org/wiki/Flechette

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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 22:49

Everyone uses their own jargon. Essentially it's a nail bomb.

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Re: Artillery Discussion Thread

Postby Singha » 24 Jul 2017 23:15

ramana wrote:Those truck mounted guns don't have stiffness and hence accuracy could be an issue.


another iran-iraq-syria shia militia thing - the so called elephant rocket. a low grade propellant & range but a heavy charge




mlrs propage gas launcher

ramana
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Re: Artillery Discussion Thread

Postby ramana » 24 Jul 2017 23:31

These are like Mughal cannons.

Thankfully IA guns are much superior.

Anyone know who makes the OFB shells? Which factory?

Manish_P

Not only did the OFBs fail to produce critical ammunition for the Indian Army, but produced poor quality ammunition, the CAG has observed.
Of the ammunition found to be faulty, the majority were 81 mm and 155 mm ammunition, the CAG observes. The 81 mm ammunition that the CAG mentions are mortars which are used respond to ceasefire violations by Pakistan. The 155 mm ammunitions are artillery shells - those used by the Bofor's Field Guns. These two alone accounted for about 59 per cent of ammunition returned.


The CAG report says 81mm and 155mm shells (~50% of the returns) were returned for cause by the IA to the OFB. Do we know what was the defects that were found?

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Re: Artillery Discussion Thread

Postby chetak » 25 Jul 2017 00:29

ramana wrote:
negi wrote:^ Side slap can cause a shell to go off if the fuze is armed and is designed to go off on impact (be it head on or grazing impact); of course all depends on how violent the side slap is i.w what is impulse which the shell experiences when decelerating within the barrel due to the side slap, however in this case side slap was not the only event that occurred as per reports shell did hit the muzzle break so if the impact was much closer to a head on impact shell would go off.


I am still studying accounts from WWII onwards and will report back.
Side-slap could result in loads up to 40,000 gs lateral.

In the barrel it is accelerating!!!

There is detonation initiation chain from the nose area which occurs only if the fuze is activated.
The side-slap acceleration could be enough to set off the explosives from the shock.
If so the broken nose would be found in debris and not initiated.

That's why all those questions.


detonation may not always be fuze initiated, especially when it happens within the barrel.

if the ammo being fired was around 12 odd years old and the barrel was very hot there is a possibility that a phenomenon called "cook off" which may have caused the explosion without the involvement of the fuze.

The behaviour of such older ammo can be unpredictable because of age and environment related changes in the propellant.

sometimes, when guns jam and they have to be cleared, on occasion the round blows up while it is being extricated/cleared. If the armourer isn't careful, while clearing the cooking round, serious injuries to fingers/hand may result.

A detailed examination of the damaged barrel by a good metallurgist will reveal grain structure details which will help him conclude the possible cause(s) of the incident. Thereafter, the guys who made the ammo as well as the guys who made the barrel can work backwards to the root cause(s).

ramana
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Re: Artillery Discussion Thread

Postby ramana » 25 Jul 2017 06:44

From a blog I found Dhanush Muzzle velocity is 885 m/sec* which in feet/sec is 2903.53 ft/sec

I also found standard twist for 155mm howitzers is 1:20 cals (Assumption)
i.e. 20*155 = 3100mm or 122.0472 inches

Applying standard formula for rpm given muzzle velocity =(m.v.)*720/twist in inches

2903.54*720/122.0472 = 17130 rpm or 17000 rpm

This is within the greater than the 2000 rpm minimum required for the M572 Fuze made by OFB

* This is fantastic. The M109 A2/A3 attains 700m/s which is its max for that caliber. In contrast Dhanush 45 cal is almost 200 m/s faster.

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Re: Artillery Discussion Thread

Postby Singha » 25 Jul 2017 07:30

885 m/sec tallies with what i read...the APDS rounds of tanks are faster around 1500 m/s but hesh and heat are fatter and slower and as is tube artillery. hesh shells are a good analogue to tube shells.

>>This is within the greater than the 2000 rpm minimum required for the M572 Fuze made by OFB

what are other armies doing - letting it go and arm within the tubes or using a different fuse? a lot of armies have long tube 52cal arty france, israel, soko, turkey, germany .... even north korea.

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Re: Artillery Discussion Thread

Postby ramana » 25 Jul 2017 09:42

We need to understand better the dynamics inside the tube. Everyone is confident that they arm 200 feet away from the muzzle. So what other feature is needed?
I really wish we get answers to my questions.
All boil down to was the detonation trail from the nose fuze initiated? Or the shell auto detonate as its a Class 1.1 explosive.

BTW 12 years for theses shells is about shell life but not unsafe. Still within use by date.

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Re: Artillery Discussion Thread

Postby Jaeger » 25 Jul 2017 10:28

ramana wrote:From Sanjay

On the artillery thread - could you educate posters that the gun most recently posted was a 75/24 pack howitzer that was used in the direct fire role during Kargil.


Very interesting. Was not aware of this piece of ordinance. Information online seems thin on the ground. Many thanks.


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