The ALH (Dhruv) ("Pole Star") is a multi-role helicopter developed and manufactured by India's Hindustan Aeronautics Limited (HAL). Military versions inducted in ARMY are for transport, utility, reconnaissance and Casualty -Evacuation roles.
There are three types of ALH being used by Army Aviation –
Conventional ALH Mk - I Glass cockpit ALH Mk -II (IADS) Shakti engine ALH Mk –III
Design Features. The ALH features a 'System Bolkow' four-blade hingeless main rotor with carbon fiber composite blades. The blades have advanced aero foils, swept back tips for reduced nose, and feature a ballistic tolerance against bullet hits of up to 12.7mm caliber. The fiber elastoner rotor head holds the blade between a pair of CFRP star-plates, with manual blade folding and a rotor brake provided as standard equipment. A four blade bearing-less crossbeam tail rotor is fitted on the starboard side of the pylon. Vibration damping is provided by an anti-resonance isolation system compromising four isolator elements between the fuselage and the main gearbox. An integrated drive system transmission comprises of the rotor hub, main transmission, upper controls and main rotor hydraulics. The ALH also features a four axis automatic flight control system, with an integrated control & stability augmentation system from France.
Airframe. The airframe makes extensive use of composites (Glass Fibre, Carbon and Kevlar) and accounts for 29% of overall structural weight and 60% of surface area. The Army helicopters include crashworthy fuel tanks, frangible couplings and infra-red suppressors for the engines. The helicopter design enables the crew to survive vertical impacts of up to 30 feet per second, due to the safety seats and a design of controlled deformation of fuselage crumple zones. The cabin was designed to seat 12 people; however 14 can be accommodated in a high-density configuration. Rearward-sliding passenger doors are featured on either end, with large clamshell doors at the rear of the cabin. The clamshell doors can be removed, in exceptional cases, to carry unusual & unwieldy loads. An under slung load hook is standard on army helicopter.