Featured Articles

The Programme

Project definition (PD) commenced in October 1987 and was completed in September I988. The consultant, chosen from four contenders, was Dassault Aviation, France. Engineers, connected with design and development of aircraft know how vital it is to get the 'definition' correct. From this flows detail de-sign, construction and eventually maintenance costs.

After examining the PD documents, the IAF felt that the risks were too high (likely shortfalls in performance, inordinate delay, Cost over-run, price escalations) to proceed further. A Review Committee was formed in May 1989. Experts from outside the aviation industry were included. The general view was that infrastructure, facilities and technology had advanced in most areas to undertake the project. As a precaution, Full Scale Engineering Development would proceed in two phases. Phase 1: design, construction and flight test of two Technology Demonstrator aircraft (TDI & 2); construction of a Structural Test Specimen; construction of two Prototype Vehicles (PVI &2); creation of infrastructure and test facilities. Phase 2: construction of three more PV '5, the last PV5, being a trainer; construction of a Fatigue Test Specimen; creation of facilities at various work centres. Cost of Phase I - Rs.2188 crores, of Phase II - Rs. 2,340 crores. Phase I commenced in 1990. However, due to a financial crunch, sanction was accorded in April 1993 and was marked by an upsurge in work. The critical path in this programme has been the design, fabrication and testing of its fly-by-wire flight control system FCS). An electronic FCS is a must for an aircraft with relaxed static stability.

The FCS also provides the pilot 'care free handling'; flight limits cannot be exceeded, which at lower speeds on aircraft like the MiG-23/27 or Jaguar, results in the loss of the aircraft. The Aeronautical Development Establishment (ADE) is the nodal agency for development of the FCS. One reason for delay of the first flight could have been the unexpectedly large effort required for coding control laws into the FCS software, which were then checked out on Minibird and Ironbird test rigs at ADE and HAL, respectively. The control laws were developed with the aid of real time simulators at ADE and BAe, UK. As a point of interest, a second series of in-flight simulation tests of flight control software took place in July 1996 at Calspan USA on an F-16D VISTA (variable in-flight stability aircraft); 33 test flights were carried out. Another reason for delay was the sanction imposed after Pokhran II in May 1999. Scientists working at Lockheed Martin, USA were sent back; equipment, software and documents were impounded. Herculean efforts brought the FCS software to a standard where the FCS performed flawlessly over 50 hours of testing on TD 1 by pilots, resulting in the aircraft being cleared for flight in early 2001.

Space constraints prevent any meaningful description of materials, technology, facilities, processes developed for execution of the project. Military aviation enthusiasts may read a monograph on Aeronautical Technology that has attained maturity through DRDO efforts; much of this technology finds application in the LCA project. The monograph was brought out at Aero India 1998. The LCA is tailless with a double-sweep delta wing. Its wing span is 8.2 m, length 13.2 m, height 4.4 m. TOW clean 8.500 kg, MTOW 12500kg. It will be super-sonic at all altitudes, max speed of M 1.5 at the tropopause. Specific excess power and g-over load data has not been published. Maximum sustained rate of turn will be 17 deg per sec and maximum attainable 30 deg per sec. Funds have been sanctioned for a Naval LCA. PD and studies in critical technology areas have commenced. The aircraft will be powered by a Kaveri engine (more information follows) and is to operate from the Indian Navy's Air Defence Ship, under construction. Launch speed over a 12 deg ramp is 100 kts; recovery speed during a no flare deck landing, using arrester gear, is 120 kts. Take off mass 13 tonne, recovery mass 10 tonne. Most stringent requirements are that the airframe will be modified: nose droop to provide improved view during landing approach; wing leading edge vortexes (LEVCON) to increase lift during approach and strengthened undercarriage. Nose wheel steering will be powered for deck maneuverability.

During early flight development, the TD aircraft will be powered by a single GE F404 F2J3 engine (7,250 kg reheat thrust). The indigenous Kaveri engine, under development by the Gas Turbine Research Establishment (GTRE) is slated for installation in a PV aircraft. Over 7,000 hours of ground testing of the core engine (Kabini) and four prototype Kaveri engines, together with flights in a Tu-16 test-bed aircraft would have been completed. Engine components have been produced by several manufacturing units, including HAL, where the exclusive Cellular Manufacturing Facility (CNC machining) was established in November 1988. A concurrent engineering approach has been followed to provide engines early in the LCA's flight development. Salient engine features include the 3 stage fan; 6 stage HP compressor with variable geometry IGV, I and II stators; annular combustion chamber; cooled single stage HP and LP turbines; modulated after-burner; fully variable, convergent-divergent nozzle; length 3490 mm; max diameter 910 mm; dry thrust 52 kN; reheat thrust 81 kN; thrust weight ratio 7.8. The 'Achilles heel; in the successful development of the LCA, in the opinion of this author, is the Kaveri engine.