After nearly two decades, India’s first indigenous rotorcraft is poised for civil certification in that nation this month, with FAA/ JAA approval expected within the year. And as its creators reveal more details of its design, Hindustan Aeronautics Ltd.’s (HAL) Advanced Light Helicopter (ALH) emerges as a capable, cleverly executed design, clearly able to hold its own against any modern design from the West.
The saga of the ALH began in 1984, when the Indian government decided its home-grown aeronautical industry should cut its teeth on a helicopter that began with a blank sheet of paper. However, the Indian designers knew a good thing when they saw it and weren’t above adapting proven technology, at least when it meant solid engineering around the very heart of their new helicopter. Impressed by the facility, simplicity and toughness of Messerschmitt-Bölkow-Blohm’s (MBB) hingeless rigid rotor system (as introduced by MBB on its widely sold BO 105), HAL contracted with MBB for design support, development and production aid on the ALH design.
“The intent was to incorporate that proven rotor technology with a lot of our own innovations for a helicopter that would serve well in missions throughout all the flight environments we encounter here in India,” said Wing Commander C.D. Upadhyay, ALH program chief test pilot and the first man to fly the ALH when flight testing began 11 years ago. “We fly helicopters in everything from dense coastal jungle to high, dry desert to the flanks of the Himalayas, the tallest mountains in the world. The helicopter we designed and built had to have the broadest possible flight envelope.”
Actual work on the ALH began in the mid-1980s, and progressed very slowly, gradually sauntering past the usual program milestones (first prototype rollout, June 1992; first flight, August 1992) at what many criticized as a snail’s pace. “Yes, to many it seems the project was slow,” admitted Upadhyay, “but it was slow for two reasons. The first is that this was India’s first indigenous helicopter design. We intended to build everything ourselves, really only subcontracting out the engines. Every component we designed was flown on the ALH for the first time. There was nothing derivative. Design, fabrication, testing and validation of every part took a lot of time, but we were content with that because we were doing more than just building a new helicopter. We were building an industrial base. We were not trying to meet an arbitrary deadline imposed on us from the outside. But then there was the matter of the engine…”
Upadhyay was alluding to the delays caused by a May 1998 trade embargo instituted by the U.S. when the Indian government refused to sign the nuclear test ban treaty and continued tests of its nuclear arsenal. In those days the ALH was to have been powered by two U.S.-made LHTEC CTS800 turboshaft engines, the 1,200-shp jointly produced Honeywell/Rolls-Royce powerplant that drives the Boeing/Sikorsky RAH-66 Comanche.
Barred from use of their desired engine by diplomatic fiat, HAL designers opted for the 889-shp Turbomeca TM333B2 engine for initial ALH production, while planning an Indian-made engine currently in development at HAL under the project name “Shakti.”
New engines were jointly developed by Turbomeca and HAL, to be known as the Ardidea by Turbomeca and the Shakti by HAL. The first Shakti (aka Ardidea 1H) will begin test stand runs in 2005.
“The idea behind the Shakti is to give the ALH the best possible hot-and-high performance,” explained Upadhyay. “Indian helicopters routinely fly at very high altitudes, and we think that with this new engine the ALH will be the most capable hot-and-high helicopter available.”
As currently powered by a pair of TM333B2, the ALH’s service ceiling is rated as 14,760 feet. Under Shakti power, a service ceiling of 19,685 feet is targeted. (Ironically, this is just about the altitude of the base camp for climbers of Mount Everest, an elusive hot-and-high goal for what have in the past been stripped-down Nepalese air force Eurocopter AStars, operating at the roof of the world in only the best weather conditions.) The Shakti is designed to produce 1,167 shp. The ALH’s main rotor gearbox is derated to 900-shp max continuous operation.
“It’s the combination of the ALH’s big cabin and its superb high-altitude performance that’s going to sell this helicopter,” Upadhyay claimed. “We developed it at HAL’s facility in Bangalore, which is near the ocean at nearly sea level on India’s east coast. But I can crank that helicopter around at our high-altitude test site and do everything I do at Bangalore at 11,900 feet and on a 80 degree day. And that’s with the less powerful engine.”
When series production of the ALH did begin (as always, slowly) about three years ago, initial production went to the Indian army, navy, air force and coast guard. To date, a total of 18 helicopters outfitted with mission equipment packages specific to the needs of their respective services have been delivered. So far just one “Dhruv,” as the ALH has come to be called (meaning “north star” in Hindi), has been leased to a commercial customer–Indian offshore oil-support operator Azal India.
In profile, the Dhruv resembles a Eurocopter BK 117 on steroids, with access to its 12-passenger interior eased by a pair of amply sized doors on each side. Cockpit entry/egress is via two more doors dedicated to just that purpose. Aft cabin access is via a pair of clamshell doors in a BK 117-style-configuration that’s sure to please aeromedical operators. And, as on the BK 117, HAL’s designers set the tail rotor up high and safely away from ground personnel.
Plans call for production civil Dhruvs to be IFR certified with a glass cockpit manufactured and integrated by Israel Aircraft Industries. Chiefly concerned with supplying the Indian armed forces with an undisclosed number of Dhruvs, HAL has admitted to a production rate of roughly one every 20 days beginning last April and extending at that rate until next March. Price (or as a company-issued document termed it, “basic indicative budgatory price”) is set between $5 million and $5.5 million. Direct operating costs are estimated at $650 per hour.