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Artillery Discussion Thread

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jamwal
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Re: Artillery Discussion Thread

Postby jamwal » 27 Jun 2017 09:57

Did you read the full article ?

A notable feature of the 105 IFG/LFG is its large range, 17.4 km(E1) 17.2 km(E2), compared to contemporary guns, like British M119/L119 105mm having a max range of 13.7 km for Charge 8 and 14.5 km for a standard M760 HE round, Russian D30 2A18 122 mm 15.4 km on an HE round. A common practise among artillery units to increase range of the guns without any major changes to the gun itself, is use to range increasing ammunition like Extended Range 105mm Base Bleed projectile or a 105mm Rocket Assisted Projectile (RAP).



Base Bleed rounds can have significant impact on increment of range (upto 30%), increasing the IFG/LFG’s solid range of 17km to 22-27 km category. I don’t need to tell you how significant this is. A RAP round is also very effective in increasing range, A D30 2A18 can shoot upto a 21.9 km using a RAP, compared to original 15.4 on a HE. M119 uses a M913 HERA (High Explosive Rocket Assisted) to significantly increase its range from 14.5 to 19.5 km. HERA rounds are not only common in 105mm category, almost all NATO armies field HERA rounds to increase their 155mm to shoot 30 km. An indigenous production line of HERA rounds could not only help in increasing 105 mm’s range but also of any other 155mm we may procure (For eg, India bought 145 M777 ULH from US, it was reported that India would be using indigenous rounds in the gun, and since they are meant for Mountain Strike Corps, such rounds can increase the area of influence of any gun ). A RAP could indeed increase the IFG/LFG’s range to 22 kms. OFB as of now, produces 155 mm HEER Base Bleed rounds but not for 105mm.

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Re: Artillery Discussion Thread

Postby Singha » 27 Jun 2017 12:10

on the flipside they are more costly.

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Re: Artillery Discussion Thread

Postby Aditya_V » 27 Jun 2017 12:46

I think there has been some work by OFB in improving the 105 mm shells to increase thier range to 20.5KM and upto 23Km, they were called Heer rounds. Article from 2014. I think Bharat Forge are aldreaddy doing some upgrade to the 105 mm IFG's

Desi Bofors' winter trials a success

OFB also hopes to get its improved shells developed for 105 Indian Field Guns (IFGs)-the basic artillery guns used by the army. The new shells developed by OFB give IFGs an additional 3 km range taking it to 20.5 kms. After recent user trials, the range table for the gun is being prepared. This means it has to be tested whether the gun can fire up to the same range from different angles.
The 105 IFG are considered best suitable for high altitude in absence of bigger ultra light howitzers being procured as it can be easily transported hung to a helicopter.

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Re: Artillery Discussion Thread

Postby rohitvats » 27 Jun 2017 13:07

There was one report of IA working with BF on new truck mounted 105mm gun. There was even a pic of in-service IA truck being modified for the gun. This is something which might see light of the day pretty soon.

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Re: Artillery Discussion Thread

Postby Avinandan » 27 Jun 2017 13:48


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Re: Artillery Discussion Thread

Postby jamwal » 27 Jun 2017 15:34

Singha wrote:on the flipside they are more costly.

Higher cost per round is insignificant when number of rounds fired is brought down.

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Re: Artillery Discussion Thread

Postby JTull » 27 Jun 2017 15:37

Buy the guns but don't spend on the bullets/don't shoot. Wah wah!

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Re: Artillery Discussion Thread

Postby Singha » 27 Jun 2017 15:43

jamwal wrote:
Singha wrote:on the flipside they are more costly.

Higher cost per round is insignificant when number of rounds fired is brought down.


unguided rounds but higher range sir, if you want to attack a target beyond regular shells the number of shells will not come down. also dispersion will be more so you might need more shells.

guided rounds come at $100K a pop when made by massa. dont know for us when we get around to make it but will not be that cheap.

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Re: Artillery Discussion Thread

Postby Katare » 28 Jun 2017 04:37

shiv wrote:
Bishwa wrote:If it is 105mm and based on the IFG, it is hard to believe it can do 22km range unassisted and 30 km assisted.

IFG is rated at 17km max range as per online article https://fas.org/man/dod-101/sys/land/row/ifg.htm

but i may be mistaken

In high altitude areas maybe?


The range is primarily a function of the gun's caliber or the length of the barrel so what's the caliber of 105mm IFG?

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Re: Artillery Discussion Thread

Postby ramana » 28 Jun 2017 05:49

105mm is the caliber.

From Jamwal's post above on this page:

A notable feature of the 105 IFG/LFG is its large range, 17.4 km(E1) 17.2 km(E2), compared to contemporary guns, like British M119/L119 105mm having a max range of 13.7 km for Charge 8 and 14.5 km for a standard M760 HE round, Russian D30 2A18 122 mm 15.4 km on an HE round.

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Re: Artillery Discussion Thread

Postby shiv » 28 Jun 2017 06:48

Katare wrote:
shiv wrote:In high altitude areas maybe?


The range is primarily a function of the gun's caliber or the length of the barrel so what's the caliber of 105mm IFG?
Propellant charge as well. But I do know that altitude of firing makes some difference and the question was if shooting at 4000 meters (eg Ladakh) as opposed to sea level would make any difference because of reduced air resistance

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Re: Artillery Discussion Thread

Postby Singha » 28 Jun 2017 07:20

i believe more than max range depth fires , higher range presents better basing and hiding options to the unit commander within indian zone.
also areas with no roads can be brought more in range

thats why perhaps 155mm m777 was taken despite us having all the 105mm pieces on the table

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Re: Artillery Discussion Thread

Postby Bishwa » 28 Jun 2017 07:48

The article messed up the gun specs.... it is possible it messed up the range also... mixed up two guns..


This is the range of the M777 which is 155MM/39 caliber (like the article)

Effective firing range M107: 24 km (14.9 mi) ERFB: 30 km (18.6 mi) base bleed

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Re: Artillery Discussion Thread

Postby Katare » 28 Jun 2017 08:13

shiv wrote:
Katare wrote:
The range is primarily a function of the gun's caliber or the length of the barrel so what's the caliber of 105mm IFG?
Propellant charge as well. But I do know that altitude of firing makes some difference and the question was if shooting at 4000 meters (eg Ladakh) as opposed to sea level would make any difference because of reduced air resistance


I don't know the answer to your question, I was adding another range related question to your question.

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Re: Artillery Discussion Thread

Postby rohitvats » 28 Jun 2017 11:19

Firing tables are updated/modified for high altitude areas for each gun type. You need to know where the shell will land.

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Re: Artillery Discussion Thread

Postby JTull » 28 Jun 2017 15:31

Don't they need to verify the tables for each type of shell, from each manufacturer and perhaps from each production lot?

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Re: Artillery Discussion Thread

Postby ramana » 28 Jun 2017 21:54

Agreed for each type of shell.
The shells from different mfg and production lots are accepted based on Lot Acceptance Tests.

So one set of firing tables for each of the shells.
That is what being developed now.

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Re: Artillery Discussion Thread

Postby Katare » 29 Jun 2017 01:00

I just looked up the science for simplistic understanding of drag's impact. This is extremely simplified example with a lot of assumption, focus is to see the effect of altitude/density change and assume rest are constant at both location.

The equation is D= Cd X A X r X V^2 X 0.5

Fire two bullets from the same gun at different elevations, one at sea level and the other at some higher altitude where air density is 20% lower.

Since it's the same type of bullet fired at sea level and at higher altitude we can leave out Cd (depends on aerodynamics of the bullet shape) and A (roughly surface area of the front of the bullet).

So what's left is D= r X V^2 X 0.5

r is density of air and V is the velocity of the bullet. So 20% reduction in r should reduce the drag by 20% but now the bullet would maintain a higher average velocity because it's dealing with a smaller drag force. Since the drag increases as square of velocity the average drag over the entire length of bullet would increase substantially to reduce the gain achieved by low density air.

These two factors work against each other and must intersect at some point on range scale so far 20% reduction in r (air density) we would have range increase of less than 20% but it should be more than what it would be at the sea level ( all other points ignored/constant). Since the actual range is dependent on the bullet shape, gun wear, local temp, humidity, wind and density of air, the only good way might be to make charts and tables at key reference locations and that is why they are doing it.

Example -

Sea level
- Air density 1 (assumption)
- Average bullet velocity 3 Km/second

High altitude
- Air density 0.8 (20% lower)
Average velocity - 3.6 km/second ( assuming 20% higher)

Sea level Drag = 1*3*3/0.5 = 18 drag units
Altitude Drag (20% higher average velocity) = 0.8*3.6*3.6/0.5 = 20 drag units (this can't be true, the number should be lower than 18)
Altitude Drag (10% higher average velocity) = 0.8*3.3*3.3/0.5 = 17.424 drag units (if this is correct assumption the increase in range would be proportional to the difference between 18 and 17.424


So in a nut shell lower drag, at high altitude, would increase average velocity (the bullet would loose speed slowly)
This increased average velocity would increase the drag as a square of change in velocity
Since these forces would work against each other the net gain in range should be small/marginal, if my math is right. Since the bullet at different air density would have different speed profile and hence drag profile, the results would need to be charted on a graph and than converted into usable numbers by some algorithm.

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Re: Artillery Discussion Thread

Postby ramana » 29 Jun 2017 04:38

Supersonic drag and lift are different. Function of mach number and length of the shell. I will find the formulae latter but generally, shells experience more lift at altitude leading to overshoot. Hence need to have firing tables for mountains.

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Re: Artillery Discussion Thread

Postby Bishwa » 29 Jun 2017 07:27

Artillery guns do exhibit longer range at high altitude.

As per Major Praveen Shawneys "Himalayan Conflict Forges Artillery Doctrine"

"Once stabilized (in siachen base camp), the FH-77B has shown itself to be both accurate and consistent, achieving a range of 42km from altitudes of 12,000ft using High Explosive Extended Range (HEER) base bleed ammunition."

In the plains the figures for the FH-77B is much lower even with HEER

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Re: Artillery Discussion Thread

Postby Katare » 29 Jun 2017 08:12

I only considered drag forces and used simple formula given at the NASA website. I am not sure what else would change, if both gun and target are at the same altitude? You can get much longer ranges if you shoot from mountain top at targets located at bottom of the mountain. At siachen indian positions are located at much higher altitude than Pakistani positions so our guns would shoot much longer but that is a result of geometry not altitude.

I'll be interestd in learning how/why lower density of air would increase/create lift in a symmetrical shape bullet? To generate lift forces you need asymmetrical structures like wings of an aircraft to get the different air velocity at its surface. How would one generate lift in a rotating symetrical wing less bullet? Can one generate lift on a fast moving sphere?

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Re: Artillery Discussion Thread

Postby Bishwa » 29 Jun 2017 08:21

This is another data point on the impact of high altitude on a bullet

"The increase in efficiency causes bullets to strike higher on the target
at high altitude than at sea level. At an elevation of 10,000 feet (3,050 m), a round fired
at a target at a distance of 1,000 meters will impact almost 70 inches higher than at sea
level."

Source : High altitude warfare: the Kargil Conflict and the future, Acosta, Marcus P.
Monterey, California. Naval Postgraduate School

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Re: Artillery Discussion Thread

Postby Katare » 29 Jun 2017 08:42

That makes sense, because higher average velocity at higher altitude would give gravity lesser time to pull it down so it will hit higher at target.

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Re: Artillery Discussion Thread

Postby Singha » 29 Jun 2017 09:01

70 inches over 1km is HUGE offset. some serious recalibrating of gunsights will be needed even at typical 200-300m rifle ranges

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Re: Artillery Discussion Thread

Postby tsarkar » 29 Jun 2017 18:38

shiv wrote:
tsarkar wrote:Field Trails is an all encompassing term, but in context of M777, it's preparation of ballistic tables and Standard Operating Precedures for regular units. The same is being done for Dhanush too.
Thank you. So it is not about importing first and then finding out if it works.


http://indiatoday.intoday.in/story/m777 ... 84904.html

To witness the field testing of newly acquired Howitzer, a US made gun, an India Today team traveled for more than 600 km from Jaipur to Jaisalmer.

At the location, the India Today team witnessed the formation of firing table. A firing table is formed to collect and collate data which can be used later during field firing. Every shot fired from the Howitzer gun was recorded. The trajectory, its speed, frequency, range, etc, was being monitored and the data recorded.

As per the contract agreement, firing tables are being prepared by the contracted agency - US Government and BAE GCS Ltd with support of Indian Army.

Researchers and personnel from US, Switzerland, and BAE systems were present at the location to assist the Indian Army in collecting the data. This data is considered significant for accurate firing during actual usage.

It can use all types of 155 mm ammunition. However, currently, its being tested on four types of 155 mm ammunition, including the HE, the smoke, the illumination and the fire bust.


http://www.financialexpress.com/india-n ... ow/674221/

According to IE, the M777 guns have been designed to fire Indian ammunition in Indian conditions.


http://www.thehindu.com/news/national/t ... 490830.ece

“Two M777 A-2 (Indian) ULHs arrived today for preparation of firing tables. During this event, the guns will fire 155-mm indigenous ammunition. As per the contract agreement, firing tables are being prepared by the contracted agency — U.S. government and BAE Systems with support of the Army,” the Army said in a statement.


The Indian suffix connotes India specific customizations. Every customer has specific requirements, so equipment have designations like Mirage 2000H (Hindustan) Mirage IIIEP (Pakistan), Su-30MKI, MKM (Malaysia) MKA (Algeria).

After firing tables are ready, three more guns will be received in in September for training purpose, the statement said.

Another officer explained that range tables are required when integrating local ammunition with the gun and calibrating it against variables such as weather and temperature.

Dhanush, an upgraded and indigenous version of the Bofors gun, is in the final stage of trials and induction is slated to begin soon.


So there is no conspiracy against Dhanush, and its field trials are firing tables being prepared and its users trained. It is actually ahead of the curve of M777 for induction.

Lastly folks, please appreciate the systematic approach of preparing firing tables and training users as a precursor to induction.

If such detailed reporting was not present, members would've gone bonkers with superstitious conspiracy theories of "field trials after induction."

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Re: Artillery Discussion Thread

Postby tsarkar » 29 Jun 2017 18:43

The IFG/LFG is a great gun but its time to move on with Dhanush & ATAGS.

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Re: Artillery Discussion Thread

Postby rohitvats » 30 Jun 2017 00:11

I've often repeated this on BRF - there was a time when divisional artillery brigade had 3 x Field Regiments and 1 x Medium Regiment. Medium was M-46 or Bofors. Field was IFG. But during 90s, most of these field Regiments we're converted to medium role. Break-up of USSR made 100s of M-46 available on cheap. IFG/LFG are used as required - mountain division still has more 105mm caliber than medium guns. M-777 is NOT a replacement for IFG/LFG - it adds medium category firepower for which M-46 was being earlier used. A role it is not suited for given gun angle issues. M-46 is field artillery for plains. We will definitely see some new 105mm avatar in IA service.

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Re: Artillery Discussion Thread

Postby Singha » 04 Jul 2017 21:40


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Re: Artillery Discussion Thread

Postby brar_w » 04 Jul 2017 21:45

Here's the same DV release on YT -


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Re: Artillery Discussion Thread

Postby Singha » 04 Jul 2017 21:53

takes 10 men per gun

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Re: Artillery Discussion Thread

Postby brar_w » 04 Jul 2017 22:06

Yup and the Marines had to have it this way because they put a 4500 kg not to exceed weight limit (compared to 7300 kg for the howitzer it replaced) on the weapon which dictated the configuration and how much advanced technology they could roll in both due to the weight itself, but also due to the fact that a lot of its cost was driven by the increased use of Titanium.

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Re: Artillery Discussion Thread

Postby Prasad » 04 Jul 2017 22:44

What is that mounted at the end of the gun like a bayonet?

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Re: Artillery Discussion Thread

Postby negi » 04 Jul 2017 22:51

^ That's a projection with a hole for towing.

Image
Last edited by negi on 04 Jul 2017 22:52, edited 1 time in total.

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Re: Artillery Discussion Thread

Postby brar_w » 04 Jul 2017 22:52

Yes, a tow catch -

Image

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Re: Artillery Discussion Thread

Postby Khalsa » 05 Jul 2017 03:22

Woah

Gun being towed with barrel towards the direction its travelling in
Cool, haven't seen that before.

Is it a better handling for hairpin bends in J&K especially Ladakh area

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Re: Artillery Discussion Thread

Postby brar_w » 05 Jul 2017 03:30


Rakesh
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Re: Artillery Discussion Thread

Postby Rakesh » 16 Jul 2017 07:41


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Re: Artillery Discussion Thread

Postby ArjunPandit » 16 Jul 2017 08:02

Rakesh wrote:M-777 Ultra Light Howitzer
http://tejasmrca.weebly.com/land-system ... t-howitzer

rakesh saar the page is getting blocked due to some proxy issues or appropriate site warning from company laptop

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Re: Artillery Discussion Thread

Postby Rakesh » 16 Jul 2017 08:21

Arjun Saar, I just checked the link. I am not facing the issue. Can you and others please try again from your home computers? Your company probably does not allow access to sites like this.

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Re: Artillery Discussion Thread

Postby jamwal » 16 Jul 2017 12:09

Weebly is ablog hosting service somewhat like Wordpress, blogspot and banned in some networks.


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