Artillery: News & Discussion

Locked
Karan M
Forum Moderator
Posts: 20773
Joined: 19 Mar 2010 00:58

Re: Artillery Discussion Thread

Post by Karan M »

Thanks Ramana. I am particularly heartened by small news items which have long term significance. For instance, how many noted on BR, the T-72s now have Mk2 ERA similar to Kontakt-V of local provenance. Now, while these won't make the T-72s invulnerable by any means, they offer significantly more protection against standard TSP FSAPDS ammo & make the T-72s viable in many tank to tank scenarios. This is a DPSU/DRDO success story and will likely go on all the TISAS tanks and ones with the most life remaining. DRDO is now looking for a private partner with production facilities, and private firms are eligible.

Further, Alpha (whose CMD is ex BEL R&D head, ex IA) has now outfitted many hundred T-72s with TISAS. Effectively, a huge chunk of our T-72 fleet (1000 tanks) are steadily receiving TISAS. Similarly over a thousand BMPs are being upgraded with TI sights. This is both a pvt sector and a procurement success story.

Similarly, DRDO has developed a new commanders TI sight for T-72s. BEL has a new STARS-V radio for tanks. There are new Integrated fire systems.. these are all iterative advances. Significantly, we now have new ammunition for the T-72 fleet, wth the Mango round. While not anywhere near cutting edge, this makes the T-72s viable against most TSP threats bar their latest Al-Khalids or T-80 UDs. At lower engagement ranges (<1km) it may even be sufficient against the tanks above.

In short, there is progress even if not as heavy as we want.
Karan M
Forum Moderator
Posts: 20773
Joined: 19 Mar 2010 00:58

Re: Artillery Discussion Thread

Post by Karan M »

Another thing. Folks may note DRDO 120mm Mk2 FSAPDS recently cleared user trials. This is but 125mm round repackaged for Arjun. Point is we have Mango equivalent capability in India. The Russian round is being purchased on accounts of compatibility with existing Russian tanks & infrastructure (firing tables etc). Its a quick boost. What it also means is the next DRDO round can now progress apace as they have the basic performance worked out for the technology & we have several reports on new tungsten alloys & propellant advances. None of this stuff makes it big ticket news like Rafale purchase etc. But it is essential for actual conflict
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Also Arjun gun is rifled which means the FSAPDS is even more difficult vs smooth bore 125mm APFSDS round.
Is the inner Fin Stabilized Discarding Sabot the same?
Singha
BRF Oldie
Posts: 66601
Joined: 13 Aug 2004 19:42
Location: the grasshopper lies heavy

Re: Artillery Discussion Thread

Post by Singha »

can a rifled barrel fire smoothbore shell?
it would seem possible albeit will not get the spin imparted by the barrel.

externally what is the visible diff between these two types of shells ?
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

https://en.m.wikipedia.org/wiki/Armour- ... ding_sabot

And see Rohit Vats thread on anti tank rounds.
shiv
BRF Oldie
Posts: 34982
Joined: 01 Jan 1970 05:30
Location: Pindliyon ka Gooda

Re: Artillery Discussion Thread

Post by shiv »

Singha wrote:can a rifled barrel fire smoothbore shell?
it would seem possible albeit will not get the spin imparted by the barrel.

externally what is the visible diff between these two types of shells ?
Not an expert but AFAIK rifled shells have a copper ring near the base which is slightly raised from the surface and this ring engages the rifling. It probably also aids sealing of leakage of propellant gases

A smoothbore shell will have to not engage the rifling leaving a series of gaps in the side corresponding to the troughs of the rifling through which gas leak will occur. That apart - the shell would probably damage the rifling and vice versa because of wobbling.

I guess a smoothbore shell will have to be encased in an outer casing that acts like a rifled shell and engages the rifling but that would restrict the muzzle velocity anyway because rifled shells typically come out at a lower muzzle velocity since some energy is used up in friction as a rotatory movement is imparted to the shell.

Googling for pictures of smoothbore shells throws up mostly sabot-discarding "narrow pointy arrows" that retain muzzle velocity over long distances and penetrate through a narrow puncture
JayS
Forum Moderator
Posts: 4567
Joined: 11 Aug 2016 06:14

Re: Artillery Discussion Thread

Post by JayS »

Singha wrote:can a rifled barrel fire smoothbore shell?
it would seem possible albeit will not get the spin imparted by the barrel.

externally what is the visible diff between these two types of shells ?
Wouldnt the internal pressure behind the projectile leak through groves for smooth bore ammo?? It would be significant impact on range, me thinks.

As a side note, good to hear DRDO round for Arjun clearing trials. I saw the news somewhere a few days ago as well. I remember to have visited ARDE while they were working on it in initial phase, some 6-7yrs ago. Likewise some other projects are bearing fruits which were nowhere in news around then. ATAGS being one of them. I agree with Karan. Things are improving on the bottomline. Particularly with current Govt's focus on short term low-hanging fruits, bang for the buck kind of projects such as smart munitions. Since only high ticket imports, and related desi projects are discussed in MSM a whole lot of desi achievements get buried under the propaganda.
nam
BRF Oldie
Posts: 4712
Joined: 05 Jan 2017 20:48

Re: Artillery Discussion Thread

Post by nam »

Karan M wrote:Thanks Ramana. I am particularly heartened by small news items which have long term significance. For instance, how many noted on BR, the T-72s now have Mk2 ERA similar to Kontakt-V of local provenance. Now, while these won't make the T-72s invulnerable by any means, they offer significantly more protection against standard TSP FSAPDS ammo & make the T-72s viable in many tank to tank scenarios.
Not just ERA upgrade, one of the CVRDE poster mentioned Kanchan armour as well.

So the upgraded T72 should have composite armour, rather than the monkey model armor.
Gyan
BRFite
Posts: 1596
Joined: 26 Aug 2016 19:14

Re: Artillery Discussion Thread

Post by Gyan »

ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Gyan, Thanks for this link. I always wondered how they fire APFDS from rifled barrel and not interfere with the fins function which requires little to no spin.

In rifled barrels its the obturating ring which is soft material which imparts little or no spin to the sabot round.

Its conceivable that both 120mm and 125mm rounds both have the same core FS round. Its only 2.5mm radial difference (that's 0.1"for the US folks) which can be made up in the sabot dimensions.
Gyan
BRFite
Posts: 1596
Joined: 26 Aug 2016 19:14

Re: Artillery Discussion Thread

Post by Gyan »

Leaving aside technical nomenclature. Smoothbore tank cannons use sealing rings to seal the escape of gases. Rifled tank cannons firing sabot rounds use slipping rings which neutralise effect of rifling grooves & reduce spin. Rifled barrels firing He or Heat shells use driving bands or rings to engage with rifling grooves for using spin to improve accuracy.
Smoothbore tank barrels require higher level of finish but are lighter and last longer. Rifled tank barrels are heavier, last less rounds but can be made more accurate with lesser effort theoretically.
There is also a view that pgk type fuses will become so cheap that rifled howitzer barrels may go out of fashion and be replaced by smoothbore howitzers specially in 39 caliber.
The second step might be even these howitzers being replaced by gliding mortar shells with pop out fins.
While long range will be done by MBRLS or missiles.
Recently HIMARS have been mounted on ships.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Gyan, If you read the aerodynamics papers on PGK type canard fuzes, they need the projectile to spin and won't work with rockets which are fin stabilized.
They need some other version for non-spinning projectiles.
Diehl had a 120 mm mortar round with flip-out fins and laser guidance package.
Vayutuvan
BRF Oldie
Posts: 12062
Joined: 20 Jun 2011 04:36

Re: Artillery Discussion Thread

Post by Vayutuvan »

I have a basic (may even be stupid) question here. Why are shrink fit the rings? Can't they simply machine them while machining the shell itself? In theory, it is a very simple change to the numerical program.

Two programs for 120 mm and 125 mm will do the trick. Shrink fit might have the problem of the ring expanding due to the heat of friction and might increase balloting. It is a failure mode that probably has been thought about and addressed I am sure.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

You want the rings to be softer than the barrel material so they can lubricate the shell as it traverses. So it's shrunk fit. In fact, due to friction the ring locally melts and reduces the coeff of friction.
The failure mode is corrosion due to dissimilar copper alloy and steel. So they recommend phosphate coating the shell to avoid galvanic corrosions.
Gyan
BRFite
Posts: 1596
Joined: 26 Aug 2016 19:14

Re: Artillery Discussion Thread

Post by Gyan »

ramana wrote:Gyan, If you read the aerodynamics papers on PGK type canard fuzes, they need the projectile to spin and won't work with rockets which are fin stabilized.
They need some other version for non-spinning projectiles.
Diehl had a 120 mm mortar round with flip-out fins and laser guidance package.
Agree.

I am of the personal view that 155mm Howitzers above 39 caliber is outdated concept. Army resistance is just like Navy which wanted heavy cruisers with huge cannons but was forced to buy missile boats in 1960s. Technology has moved since last 30 years.
Vayutuvan
BRF Oldie
Posts: 12062
Joined: 20 Jun 2011 04:36

Re: Artillery Discussion Thread

Post by Vayutuvan »

Ramana ji, thanks. One learns lot of practical stuff everyday on brf.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

So when are the Dhanush UET to resume in November?

Eagerly await the results.

Have the decided on root cause for the M-777 shell burst in barrel?
Thakur_B
BRF Oldie
Posts: 2404
Joined: 11 Aug 2016 06:14

Re: Artillery Discussion Thread

Post by Thakur_B »

Apparently Saurav Jha has withdrawn his tweet where he mentioned OFB has beaten out pvt competition for M-46 upgunning tender for 300 guns.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

What about this quote from an OFB official (unnamed) that they won the up-gunning contract?

viewtopic.php?p=2226526#p2226526
Katare
BRF Oldie
Posts: 2579
Joined: 02 Mar 2002 12:31

Re: Artillery Discussion Thread

Post by Katare »

Admiral, that article of yours was posted on the last page, on Oct 30th and has been the main source of discussion since than. Slipping on BRF duties are we? :mrgreen:
Rakesh
Forum Moderator
Posts: 18274
Joined: 15 Jan 2004 12:31
Location: Planet Earth
Contact:

Re: Artillery Discussion Thread

Post by Rakesh »

Aiyoo! Result of Old Monk Rum :)

Will delete. Weird though, article had date stamp of Nov 10th.
brar_w
BRF Oldie
Posts: 10694
Joined: 11 Aug 2016 06:14

Re: Artillery Discussion Thread

Post by brar_w »

Some Short term M777 capability (Moving target attack) -

Image

Image

Image

Image

Image

Image
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Per the frontline, Dhanush trials were to resume in November. Its close to middle of the month any news?
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

marten once asked the burst pattern of 155mm shell.

I have picture from a Canadian book. Essentially due to the stiffness the nose and base fragment into large pieces and the middle conical and cylindrical portion will fragment into very tiny pieces. The dispersal is spread about 50m for lethality and ~ 100 meters for injuries. The purpose of the fuze is to burst at proper height to give maximum dispersion of fragments.

In addition the ER/BB and BT shells have high fragmentation steel which gives maximum fragment dispersion.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Some root cause for the Dhanush and M777 shell bursts in barrel

Arty shells broke up in barrel during recent misfires


Artillery shells broke up within barrels during recent misfires
Shishir Arya | tnn |
Updated: Sep 28, 2017, 19:24 IST

Nagpur: Misfires have been reported over the last five months in two artillery guns, US' M777 howitzers recently delivered to India, and the home made Dhanush, modelled on the Swedish Bofors. In all these incidents between May and September, the shell did not explode, but had fractured within the barrel before coming out, probably due to pressure.

The shell had hit the muzzle of Dhanush's barrel during test fires in May and July. The muzzle, which is on the top of the barrel was damaged in the incident. A similar incident was reported in the American M777 ultralight howitzers on September 2. Sources say the damage to M777 was much more severe as compared to Dhanush. The first batch of 25 M777s were delivered by BAE Systems in May this year.


However, it is too early to say whether the shell or the gun is faulty, say sources involved in the matter. The Ordnance Factory Board (OFB) has said a joint investigation is underway in the M777 incident. Primary investigation into May's incident with the Dhanush points to problems in the shell. Now, the entire case is being studied with a fresh perspective, said sources. This is a peculiar situation, say experts involved in the case, as shell fracturing is not common.

Artillery shells used by the Army are manufactured in ordnance factories located across Vidarbha. The shells are made in the ordnance factory at Ambajhari and the explosives are manufactured at Bhandara. In all the three incidents, the shells used were made by the ordnance factories. Now, due to the similar problems, a relation is being suspected in all the cases.


Sources involved in the probe say that the reason cannot be easily pinpointed and a detailed investigation is underway. If needed, changes may be made in the Dhanush guns. However, before this, the need for the changes will have to be confirmed. Since misfires have happened once in 1,200 rounds, it's difficult to ascertain the exact cause. There are plans to conduct intense internal trials of the gun before going for another round with the Army, said sources.

{What they are saying is its rare event and hence cant pin down the exact cause.}

In 2013 too, there had been a barrel burst in the Dhanush. It had led to major damage to the barrel but there were no casualties. At that time, it was a rouge ammunition that had burst within the barrel, says the report.


Data accessed by TOI shows that there were cases of muzzle hit and barrel burst in the original Bofors too. In three instances, 'bore premature' has been mentioned as the reason. This means the shell exploded prematurely, within the barrel. There are a couple of reports in which the inquiry says that neither the gun nor ammunition could be blamed. :?: :?: :?:

Earlier, shells manufactured by South African firm — Naschem — were used in the original Bofors guns. Nearly a dozen instances of barrel or muzzle being damaged took place with the Naschem ammunition, says data with TOI.

There have been earlier instances of accidents in the M777 guns too. This year, two soldiers died in an explosion within the barrel during an engagement with the IS in Iraq. There were two separate incidents in 2014 in the US and Australia, apart from March 2011.

{So its not impossible but rare event and has occurred in other countries also. Not unique to India only.}

Record range achieved using same shells

Recently, developers of the ATAGS, another 155mm gun, claimed that it set a world record by achieving a range of 48km. Based on a design by Armament Research and Development Establishment (ARDE), a unit of the DRDO, the gun is being developed by Tatas and Bharat Forge.

Incidentally, the shell used during the trials when the record was achieved has also been made by the ordnance factories. A source in one of companies engaged as development partner of ATAGS said, "Though the shell had achieved a record range, it was with the barrel manufactured by us." :((

"Range is a function of propellent charge and capacity of the weapon to withstand pressure. Earlier imported, the propellent is now made by the ordnance factory," the source said.
To my one track mind this is a very clear case of balloting or spinning top issue.

To recollect this happens when the clearance between the bourrelet (the cylindrical portion of the shell) and the barrel has excess clearance, the shell center of gravity is off axis to one side i.e. eccentricity (this causes the shell to spin like a top and wobble around the rotating band), and if the charge is maximum(to give maximum range) which gives most energy to this spinning shell.As the shell travels along the barrel it hits the sides of the barrel due to the wobbling motions. As the shell slaps the barrel with a lot of force (up to 40,000 gs = 100 lbs (weight of shell) * 40,000 = 4 Million lbs force!). This huge force can shatter the shell and the fuze breaks off without functioning. To exacerbate the situation the shell is the ERFB/BB unit as the above report says was used on the ATAG models and achieved large range of 48km. The ERFB is made with frangible steel to give maximum fragmentation effect. The steel has low fracture toughness in order to break up into very small pieces. So its like a cast iron shell that shatters when dropped with high force or hit with sledge hammer.
And to confirm this recover the fuze and verify its state of functioning. I am willing to bet the fuze never functioned.

One avenue of investigation should be to take ten shells from each lot of those shells and measure the bourrelet diameter and to put them on a spin table (moment of inertia measuring machine) and see how they measure up. Then call the ARDE folks and conduct a balloting analysis on their software. I know they have this software for they write articles in Defence Science Journal.
Also tabulate all the incident with:
Date, Type of shell, Type of Charge, Fuze Comments

Comments can be if the shell was a first of firing or in the midst of a volley. The reason here is if there is residue due to tempo of firing, the shell does not seat properly. Looking at the shell shattering I think this unlikely.
And who made the shell OFB or foreign supplier

This table will point out what is common and what is different in all the above incidents that Shishir Arya notes with Bofors (3+2), Naschem (12), Dhansuh (1+2) and M 777 (1). Total 21 instances.

Based on results of this they need to put more controls on the shell manufacture at OFB Ambajhari where the shell is machined.

Do we have any BRF members in Nagpur who can contact Shishir Arya of TOI and take a dekko of the records if he still has them?

I don't think they need to make any changes to the Dhanush barrel.
Its the shell dimensional and procedures updated based on ARDE analysis.

Links to past posts:

Discussion on M107 vs. ERFB shells: viewtopic.php?p=2221916#p2221916

ERFB shell materials viewtopic.php?p=2222838#p2222838
Vinay_GR
BRFite -Trainee
Posts: 19
Joined: 15 Aug 2017 20:16

Re: Artillery Discussion Thread

Post by Vinay_GR »

dear Gurus :) will the countless and endless trail's end and are we going to induct any on the indigenous artillery units any time soon
Singha
BRF Oldie
Posts: 66601
Joined: 13 Aug 2004 19:42
Location: the grasshopper lies heavy

Re: Artillery Discussion Thread

Post by Singha »

the need for quality becomes more important as one moves to higher fire rates and higher pressures of 155mm from the old loosey goosey 105mm types.

clearly there are areas where our OFBs are not exactly running like a smoothly oiled Honda plant. the only way out is let ammo be manufactured by the private sector using whatever machinery and expertise they need to buy or import. their workers usually from machine tools and automotive background will be more disciplined as well. and their managers more watchful and process oriented.

we have already lost years of time .... how long will this circus go on? the new 155mm circus started in 1998 after kargil...today its on verge of 2018...I was unmarried brf fresher in 1998, today my son is in grade 7 .... :rotfl:
Yagnasri
BRF Oldie
Posts: 10390
Joined: 29 May 2007 18:03

Re: Artillery Discussion Thread

Post by Yagnasri »

Please wait for your grandchildren to come we are in the fast track mode in a bullet train speed.

On the serious side, I think we have already made progress in this sir. I do not see any import lobby messing up things now. At least I hope they can not at this stage.
Pratyush
BRF Oldie
Posts: 12195
Joined: 05 Mar 2010 15:13

Re: Artillery Discussion Thread

Post by Pratyush »

Import lobby can only mess up things when domestic suppliers are only OFB. By involving OFB and pvt sector players the ATAGS has become too big to fail. The dhanush can still be scrapped. Bit of that happens. It will just be replaced with the ATAGS.

So no worries in any respect WRT Arty.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

I think the way ahead is to come up with ERFB shells from low carbon steel such that they have high fracture strength and don't shatter in the barrel. In other words make them with material from M107 type shells.

Have M107 shells ever burst in the barrel in Indian Army usage?
Gyan
BRFite
Posts: 1596
Joined: 26 Aug 2016 19:14

Re: Artillery Discussion Thread

Post by Gyan »

So import of M777 continues but Dhanush goes back for more trials?
la.khan
BRFite
Posts: 467
Joined: 15 Aug 2016 05:02

Re: Artillery Discussion Thread

Post by la.khan »

Pratyush wrote:Import lobby can only mess up things when domestic suppliers are only OFB. By involving OFB and pvt sector players the ATAGS has become too big to fail. The dhanush can still be scrapped. Bit of that happens. It will just be replaced with the ATAGS.

So no worries in any respect WRT Arty.
Good to hear this! So, once the trials are completed and IA approves the gun, all pvt players (Tata or BF or ????) have to do is hit their production stride and churn out 4-5 guns per week? I hope we induct 200-250 guns a year. A 1000 ATAGS will be an awesome asset :twisted: on either of the borders.
Will
BRFite
Posts: 637
Joined: 28 Apr 2011 11:27

Re: Artillery Discussion Thread

Post by Will »

Heard the OFB's are planning on going on strike pretty soon. Maybe a good idea for the govt to announce a lockout and get rid of those white elephants. But does anyone :mrgreen: have the will??
Vips
BRF Oldie
Posts: 4699
Joined: 14 Apr 2017 18:23

Re: Artillery Discussion Thread

Post by Vips »

The union leaders should be treated like anti-nationals that they are and made an example of. They are bound to be in touch with Opposition party leaders or even some outside elements, there should be a sting operation and they should be systematically targeted, tracked and exposed.

I would go even a step further and treat them as Naxals/Terrorists threatening India's security.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

ramana wrote:I think the way ahead is to come up with ERFB shells from low carbon steel such that they have high fracture strength and don't shatter in the barrel. In other words make them with material from M107 type shells.

Have M107 shells ever burst in the barrel in Indian Army usage?

Chances of Muzzle Strike or side slap happen in longer barrels.
When this happens with HF-1 family of high fragmentation steel then high probability of shell burst.

I looked at US M749A1 and M795 ERFB shells in the US Army manuals on line.
Both are HF-1 steel. These are high fragmentation steels.
Its matter of time they also get shell bursts.
One thing would be to fire them from 39 caliber guns to reduce the accidents.
If requirement is to fire from longer 45 and 52 caliber guns then revert to M 107 style high ductility shells that can withstand the side slap.

I would use M 107 with Base bleed motors for extra range and PGK type fuze,
We get range and target lethality with accuracy.
Crew Safety is bonus.
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

Have the Dhanush and M777 trials resumed as stated in Frontline article?
ramana
Forum Moderator
Posts: 59773
Joined: 01 Jan 1970 05:30

Re: Artillery Discussion Thread

Post by ramana »

I wonder when.ARDE PGK will be tested? Would be major milestone.
Pratyush
BRF Oldie
Posts: 12195
Joined: 05 Mar 2010 15:13

Re: Artillery Discussion Thread

Post by Pratyush »

ramana wrote:I wonder when.ARDE PGK will be tested? Would be major milestone.
Indeed, when accepted into service it will address one of my biggest pet peeves regarding long range Arty.

But the numbers will have to go beyond khadi gram udyog numbers.
shiv
BRF Oldie
Posts: 34982
Joined: 01 Jan 1970 05:30
Location: Pindliyon ka Gooda

Re: Artillery Discussion Thread

Post by shiv »

Pratyush wrote:
ramana wrote:I wonder when.ARDE PGK will be tested? Would be major milestone.
Indeed, when accepted into service it will address one of my biggest pet peeves regarding long range Arty.

But the numbers will have to go beyond khadi gram udyog numbers.
Please do not use needlessly derogatory expressions about stuff that originates in India.
tsarkar
BRF Oldie
Posts: 3263
Joined: 08 May 2006 13:44
Location: mumbai

Re: Artillery Discussion Thread

Post by tsarkar »

Another shot in the arm came when DAC under the aegis of Hon’ble Raksha Mantri Smt Nirmala Sitharaman cleared the Limited Series Production (LSP) of 40 ATAGS.
Wonder which one was chosen, Tata or Kalyani?
Locked