Extra 250 kg weigh down HAL's Light Combat Helicopter project

Visitors to Aero India 2009, to be held in Bangalore from February 11 to 15, who hoped to catch a first-ever glimpse of India’s high-tech Light Combat Helicopter (LCH), will return disappointed. Hindustan Aeronautics Limited (HAL) has told Business Standard that design glitches — including extra weight and delays in manufacturing the tooling on which the LCH will be fabricated — have pushed back the first flight by up to a year.

Some consolation will be afforded to enthusiasts of indigenous production from the first display flights of a black leopard-painted prototype of the armed Dhruv Advanced Light Helicopter. Called the Weapons Systems Integrated Dhruv (WSI Dhruv), this is the machine on which the LCH’s armaments and sensors are being perfected, even as designers struggle to pare down the extra 250 kilos that have come up on the LCH.

“An extra 250 kilos may not seem much on a 5.5-tonne helicopter, but it really is a serious problem,” explains HAL’s helicopter design chief N Seshadri. “At altitudes of 6,000 metres (almost 20,000 feet), which the LCH must operate at, the air is so thin that it can only carry a weapon payload of 350-500 kg. If the helicopter ends up 250 kg heavier than planned, its high-altitude firepower will be dramatically reduced,” he says.

Being built on the basic design of the Dhruv ALH, the LCH is currently HAL’s most prestigious project. Many of its components, 
including the engine, crucial moving parts like the rotor, and the instrumentation of the LCH, have already been tested on the Dhruv.

Armaments and the sensors are taking shape on the WSI-Dhruv. With much of this already done, HAL had planned to fly its first LCH prototype by December 8, 2008. A second prototype was to be readied in the first half of this year. But that timeline has turned out to be too ambitious.

One reason for this is that the LCH is technologically far more complex than the Dhruv. The Dhruv is a utility helicopter, designed for simple tasks like reconnaissance, casualty evacuation and for conveying small teams of up to seven soldiers. In contrast, the LCH is an attack helicopter, a flying weapon platform built purely for combat. It must fly and fight by day and by night, bringing down missile, rocket and cannon fire on dangerous enemy targets like tanks. To avoid detection by radars and individuals, it must fly almost at ground level and its crew needs bulletproofing against ground fire. It must have sophisticated electronics to confuse enemy radars.

Plexion Technologies, the private sector company that has designed the LCH’s fuselage, is working overtime to cut down the extra 250 kg. Meanwhile, HAL is trying to convince the air force to accept the first prototype with some extra weight so that flight tests can begin even as Plexion slims down the LCH.

There are some delays also in selecting the weapon systems that the LCH will carry. The air-to-air missile, which will be bought from abroad, has not been selected. The LCH was to be fitted with the DRDO’s Nag anti-tank missile, but the services want a missile that can hit tanks at seven km, compared with Nag’s four-km range. So, while the DRDO works on a longer-range version of the Nag (called the HELINA, or helicopter-mounted Nag), a foreign missile will have to be bought as an interim solution.

Tomorrow: Aero India spotlight on the Light Combat Aircraft