Dhruv ALH at Aero India 2011. Photo Copyright © Vijainder K Thakur
The Advanced Light Helicopter (ALH) program was first announced in November 1984. The helicopter was designed with assistance from Messerschmitt-Bölkow-Blohm. The first prototype flew in August 1992.
The project was completed in June 2001 at a cost of Rs. 2,488 crore of which the Army’s share was Rs. 809 crore.
The Dhruv is currently in service with the IAF, IA, IN and border security force. In addition, the aircraft is used by several national and state agencies.
The Dhruv is of conventional design with a high tail boom that allows easy access to the rear doors.
Dhruv uses composites extensively to reduce weight. Nearly 29% of it empty weight (60% of the airframe surface) comprises composites.
Its twin 1000 shp Turbomeca TM333-2B turboshafts are mounted above the cabin and drive a four-blade composite main rotor.
The main rotor can be manually folded; the blades are mounted between carbon-fibre-reinforced plates, the rotor head is constructed from fibre elastomers.
The cockpit section of the fuselage is of Kevlar and carbon-fibre construction; it is also fitted with crumple zones and crashworthy seats.
The aircraft is equipped with a SFIM Inc four-axis automatic flight control system. Avionics systems include a HF/UHF communications radio, IFF recognition, Doppler navigation, and a radio altimeter; a weather radar and the Omega navigation system were options for the naval variant.
An active vibration control system (AVCS) developed by US helicopter company Lord Corporation monitors onboard conditions and cancels out fuselage vibrations.
The Mk.1 features a conventional cockpit and was powered by Turbomeca TM 333-2B2 turboshaft engines. A total of 56 aircraft were delivered to the Indian military.
The Mk.2 features a HAL-IAI developed glass cockpit. A total of 20 aircraft were delivered to the Indian military.
The Mk. 2 included the following advanced features.
The Mk.3 is powered by Shakti engines and features electronic warfare (EW) suite and warning systems, automatic chaff and flare dispensers, and improved vibration control system.
The first batch of 10 Dhruv Mk.3 were inducted into service in 2012.
The helicopter was initially powered by two Turbomeca TM 333-2B2 turboshaft producing 746 kW (1000 shp).
However, the performance of the helicopter with the B2 engines fell short of QR. The ALH was not able to fly above 5000 meter, though the Army’s requirement stipulated up to 6,500 meters. The vibration level at extreme altitudes was not within the acceptable limits.
Dhruv Mk 3, the latest version of the helicopter uses two more powerful Shakti engines jointly developed by HAL and Turbomeca producing 900 kW (1,200 shp).
On December 14, 2011, Minister of State for Defense Shri MM Pallam Raju told parliament that 69% of the material used in Advanced Light Helicopter (ALH) is procured from foreign sources. However, around 90% of the components are indigenously manufactured,
Critical components that have been indigenized include Rotor Blades and main gear box. HAL was earlier importing rotor blades but is now manufacturing them locally. [via PIB]
In September 2007, the Dhruv Mk 3 was cleared for high-altitude flying in the Siachen Sector after six-month long trials. In October 2007, a Dhruv Mk 3 flew to an altitude of 27,500 ft ASL in Siachen. This was the highest that the Dhruv had flown, and was higher than the 25,000 ft record set by an IAF Cheetah helicopter in 2005.
The Dhruv was designed to hover in ground effect at 20,000 feet, carrying 200 kg of payload.
In summer 2010, a Dhruv powered by Shakti engines hovered over the Indian Army's Sonam Post, close to Siachen, at a altitude of 21,000 ft with a payload of 600 kg.
The Dhruv powered by the Shakti engine continues to fall short of the power requirements projected in the Army QRs and HAL is making efforts to reduce the weight of the helicopter and increase the power of its engine.
Current versions of the Dhruv features a glass cockpit.
In September 1995, the Army projected a requirement of 99 helicopters to be inducted by 2007 which was later scaled down to 40.
Despite the shortcomings of the aircraft with the B2 engine four ALHs were accepted by the Army and an order for eight more was placed to sustain the production lines of HAL. The Defense Minister provided a one-time waiver for ALH not meeting the QRs following assurances by HAL to identify a more powerful engine to replace the B2 while trying to improve its performance and reduce the basic empty weight of the helicopter from 2,450 kg to 2,250 kg.
In December 2007, the Ministry finalized another three contracts with HAL for procurement of 105 ALHs for the Indian Army, which were to be fitted with newly developed Shakti engine.
The IAF separately ordered 54 Dhruvs powered by Shakti engines.
On January 1, 2012, the Indian Express reported that the MOD was likely to place an order for an additional 45 Advanced Light Helicopters. The helicopters, estimated to cost Rs 3,310 crore, will come in three variants — utility, armed, special operations.
In October 2008, Defense Minister A. K. Antony announced that the Indian Navy had concluded that the Drhuv was unsuited for operations onboard ships because of its poor performance when fitted with folding blades and unsatisfactory maintenance record.
HAL currently has orders to deliver 260 to 270 Dhruv worth Rs 16,000 crore, its Chairman Ashok Baweja said on Thursday, February 12, 2009, at Aero India 2009 in Bengaluru.
Five Dhruvs were handed over the Ecuador Air Force chief at a high-profile media event at Aero India 2009 on Friday, February 13, 2009.
Five Dhruvs were handed over to the Indian Army at Aero India 2011 as the first tranche of the order for 105 helicopters.