Dhanush 155mm/45-calibre

Dhanush is a 155x45 Calibre indigenous gun developed by OFB. DRDO is developing 155 mm / 52 Cal Advanced Towed Artillery Gun System (ATAGS) that will upgrade the 155 mm / 45 Cal Dhanush in the future.

Dhanush as an artillery system has proved to be one of the best amongst its class. A 45 Calibre towed gun system capable of targeting at long ranges incorporating autonomous laying features and having one of the most sophisticated suites of electronic and computing systems in the world. The weapon has got maximum range greater than 8 to 10 Kms in comparison to the existing in-service 155mm x 39 Cal Bofors Guns with better accuracy. It can fire all types of ammunition available with Indian Army.

It is a ‘Make in India’ effort in true sense with more than 80% indigenous items. Ordnance Factories have the potential and the opportunity to become the leading player in the acquisition programme of the Indian Armed Forces and to position themselves as a link in the global defence supply chain. To develop this gun, OFB has utilised the expertise available with DPSUs and Indian private industry like BEL, MIDHAMI, M/s Dental. With the development of Dhanush, India has developed the capability to manufacture 155mm Guns for which the country was till now dependent on foreign countries.

OFB has undertaken a project of development of 155 mm 45 cal Gun System with limited scooting abilities. The main systems of the gun are hydraulically operated which is powered by a prime mover mounted on the gun and complete system is controlled electrically. The basic features of the gun are propulsion, laying, loading of ammunition, firing and deployment of the gun as well as tandem driving by a towed vehicle.

The weight of the complete Gun is l2.7 tonnes. ln case, a new engine other than OM 616 D98 specified by the OEM is proposed, the engine aggregate should be ergonomically and adequately accommodated in the available enclosed space and mounted on the existing mounting points with suitable bearers and buffers to with stand acceleration of 59 in all directions. The vendor should keep the space constraints in mind while offering the engine aggregates.

The power plant will drive two hydraulic axial piston pumps which in turn will supply the high pressure fluid to the hydraulic motors for driving the wheels, as well as for operating the loading and laying equipment of the gun. The power plant will also generate electric power, through an alternator, required for the operation of the electric & electronic devices in the gun and charging two 1-2V cold start batteries in series. The air compressor, which is also included in scope of work, is to be mounted on the engine body. The compressor supplies compressed air for operating the wheel brakes.

This 45 Calibre towed gun system, capable of targeting at long ranges, incorporates autonomous laying features and having one of the most sophisticated suites of electronic and computing systems in the world. The tactical game-changer 'Dhanush' 155 mm x 45 calibre Artillery Gun system. It has an effective range of 38 kms in the plains and has advanced day and night direct firing system. ‘Dhanush’ is a unique model of synergized approach for development of a complex system involving all stakeholders, which had undertaken upgunning of 130mm gun to 155 x 45 calibre.

In the Artillery modernisation plan, the Indian army needs 814 Mounted Guns, 1580 Towed Guns, 100 tracked Self Propelled guns,180 wheeled Self Propelled guns and 145 Ultra Light Howitzers. In the twelfth army five year plan 2012-17, which is in consonance with Artillery Profile 2027, the Indian army planned to upgrade its existing field regiments presently equipped with 105 mm Indian Field Gun, 105 mm Light Field Gun and the Russian 122 mm guns to the 155 mm towed gun. The Army’s Field Artillery Rationalization Plan, drawn in 1999, aims to acquire 2,800-3,000 155 mm/52-calibre guns of all kinds and 155 mm/39-calibre lightweight howitzers by 2027. The next batch of Dhanush will be in line with this target and its barrel for the next batch will be 52 calibre.

Dhanush 155 MM/45 calibre gun is based on the 1980’s Bofors FH-77B/39 Calibre artillery gun design and aided by the transfer of technology (ToT) clause signed in the 1980’s with the Swedish company. The Indian version had several improvements to make Dhanush compatible with today’s modern communication techniques. It has an effective range of 38 km as against the 27-km range of the original Bofors. It has a system to auto-correct any variations in ammunition and atmospheric pressures. The gunner has a high resolution sight besides an infrared sight. Its electronics suite enables real-time adjustments for moving and static targets.

The OFB, an organisation under the Ministry of Defence, first unveiled the Indian version of the gun in February 2014 and handed it over to the Army for intensive tests. These were successfully conducted. In the trials being conducted in 2014, structural evaluation of ‘Dhanush’ was carried out as per the design requirement communicated by the manufacturer. The Proof and Experimental Establishment (PXE), Chandipur team formulated the mechanism to measure recoil-run out phenomena, blast pressure profile at multiple locations, muzzle flash simultaneously in time synchronized manner. This enabled the user to evaluate the gun structure comprehensively in a very short time frame.

The indigenously designed and manufactured 155mm x 45mm calibre artillery gun, Dhanush successfully met all technical parameters during the winter and summer trials. Informing the Members of Parliament of the Consultative Committee attached to his Ministry, the Defence Minister Shri Manohar Parrikar said 27 April 2015 Dhanush incorporates many improved features than the guns which the Army is possessing at present. The Consultative Committee was discussing the Role Performance and Future of Ordnance Factory Board (OFB), one of the oldest and largest production organisation of the Ministry of Defence. OFB is a conglomerate of 39 ordnance factories with another two new projects being set up at Nalanda in Bihar and Korwa in Uttar Pradesh.

The final trials of indigenous artillery gun Dhanush started in June 2016. Spread over the next six months, these trials were of a production-level prototype. This was supposed to be the last lap of trials before the Ordnance Factory Board started bulk production. The Army used six such guns at various locations to test its firing ability during summers and also in the winters in the Himalayas. The first three guns of the production-level prototype underwent four-month trial from June to September. Between October and December, three other guns were added and the entire lot was tested in high altitude winter conditions.

The Dhanush is based off the FH-77B, as India acquired the schematics to the gun. Its primary advantage over India's aging arsenal of FH-77B's is a larger caliber, a longer effective range, and a faster rate of fire. The guns were intended to be made of 80 percent domestically-manufactured components. However, it was later revealed that wire race rollers that were labeled "Made in Germany" had actually come from China — and were defective to boot.

The MoD set a stiff delivery schedule. The first 18 guns were to be delivered in 18 months after the signing of contract. Another 36 guns were slated for delivery over the 12 months thereafter. The remaining 60 guns were to be delivered by June 2020. India ordered 114 Dhanush howitzers, which were intended to be phased in between the end of 2017 and sometime in 2019. This cost New Delhi about $2 billion. Eventually, they hope to replace the entire FH-77B arsenal with 414 Dhanush.

Dhanush towed howitzer may be domestically produced, but by September 2017 a multitude of failed tests proved that the weapon was unready for war. An Indian Army source told Defense News that the artillery gun hae failed three times in as many months, pushing the induction date back further and further. "The Dhanush 155mm/45-caliber artillery gun has failed on three occasions in a row in the last three months when the shell of the gun hit the muzzle brake in one of the six prototype guns currently undergoing user trials," the source told Defense News.

"Shells hitting the muzzle brake could be due to a number of reasons such as overexploitation of the munitions, overcharging of the munitions and so on or even faulty ammunition; all of these aspects will have to be evaluated," said Rahul Bhonsle, retired Indian Army brigadier and defense analyst, to Defense News.

This wasn't the first time the Dhanush has encountered troubles. In July 2017, The Times of India reported that "in May when six guns were being fired at one go, a shell hit the muzzle brake in one of the pieces…Last week when the test fires were being undertaken, again a shell hit the muzzle brake, bringing the whole process back to square one."