India's National Aerospace Laboratory working on regional jet

India's National Aerospace Laboratory working on regional jet

6 October 2007

Having already delivered 10 indigenously-developed Hansa two-seater trainer turbo-prop aircraft, the National Aerospace Laboratories (NAL) at Bangalore is well on its way to developing the 14-seater Saras light transport aircraft, Dr AR Upadhya, director, NAL, told a packed auditorium at Zephyr 2007, the aerospace meet of the Indian Institute of Technology (IIT) at Powai, Mumbai, on Saturday 6 October.

Two prototypes of the rear mounted twin-engine Saras are already ready, with the aircraft having made its successful maiden flight, powered by Pratt & Whitney engines, on 14 April 2007, Dr Upadhya said. He said full flight certification was expected in 2009. The aircraft earlier was about 500kg overweight, which had been reduced by a greater use of light carbon-fibre composites and a more powerful engine.

NAL is also working on a four- and six-seater aircraft, presently named NM5, in a public-private partnership with Mahindra Plexion, and expects the first flight of the prototype to take place by the end of 2008.

But the most ambitious NAL project is a 70-seater regional jet, which is to have a 50-seater turbo-prop variant as well as a 90-seater extended version.

Apart from regional jet makers Bombardier and Embraer, a number of countries are already in advanced stages of production of regional aircraft, including China, Russia and Japan, Dr Upadhya disclosed, adding that to be successful, NAL's version would have to be lighter and therefore more fuel-efficient than those made by its competitors.

He was quick to add, though, that civil aviation was only one of the dozen or more divisions in NAL, and that the laboratories were technology providers to all sectors of the aerospace industry. NAL also has longstanding foreign collaborations with a number of countries, including China Aerosspace (CAe) and jet turbine makers Pratt & Whitney, with whom it has jointly set up a number of jet propulsion test equipment stations.

Among NAL's more visible achievements is its expertise in carbon fibre composites, a field in which it has made a number of developments, including a pilot project to manufacture the raw materials. It has also pioneered new lower-cost methods through vacuum-enhanced resin infusion technology for making composite components (being used for the wings of the Saras aircraft), as well as indigenously developed autoclaves for curing, which are used by Indian aircraft maker Hindustan Aeronautics Ltd (HAL).

The composite wings for India's prestigious fourth-generation Light Combat Aircraft (LCA) have spars developed by NAL, which has also developed the middle part of the fuselage and airframe, as well as the doors for the landing gear. Around 90 per cent of the LCA's surface, and 45 per cent of the aircraft by weight is made from advanced composites.

Compsites technology is also used for repair of Indian Air Force aircraft, in making radomes for Doppler radars used for weather forecasting by the Indian Space Research Organisation (ISRO) and to make radomes for IAF aircraft. Upadhya said that the NAL has a number of collaborative projects in these areas with HAL. The institution has also specialised in failure analysis, and its scientists and engineers are always involved in crash investigations, he said.

Among other pioneering projects is developing shape memory alloys, to be used for the fins of the reusable launch vehicles being developed by ISRO, developing hydrophobic coatings to bring down laminar flow in aircraft and spacecraft, and developing the technology to burn fuel at supersonic speeds in scramjets, required by ISRO for its air-breathing hypersonic launch vehicle.

It has also developed a prototype for a 55 HP Wankel rotary engine, and is working on a microgas turbine, for which all the parts have already been produced and integration is underway. Another field is development of micro-air vehicles, for surveillance purposes.

In launch vehicle space technology, the NAL has developed Zirconi-based ceramic inserts for high temperature tolerances up to 3,200 degrees Kelvin. It has also developed mouldless slurry casting, nano-technology coatings for precision tools and magnetic non-contact bearings. A runway visibility meter its has developed is now used at a number of airports, including at Goa and Kochi, Dr Upadhya said.

Test equipment is vital to the field of aerospace, and this is one of NAL's specialities, Dr Upadhya pointed out. Among test equipment developed is wind tunnels, both for aviation as well as space flight, aero-elastic modelling techniques, computational fluid dynamics, flow visualisation and pressure-sensitive paint, G-meters for aircraft, software to monitor aircraft performance, active noise control devices, and a semi-free jet test rig (with Pratt & Whitey).