OPINION | How good is Tejas?

Air Combat Capability

IAF's Light Combat Aircraft Tejas manouevers during the second day of Aero India 2019 at Yelahanka Airbase in Bengaluru February 21, 2019. DH Photo/Janardhan B K

The MiG-21 has been in the news again — for all the wrong reasons. That aircraft has been the mainstay of the Indian Air Force’s (IAF) air combat capability for decades. However, current developments bring into focus the urgency of further developing and deploying the Tejas Light Combat Aircraft. The IAF plans to order a total of 339 Tejas aircraft of successive iterations. These will form the mainstay of the IAF’s combat aircraft fleet for some decades. A small number are also to be ordered by the Indian Navy for carrier-based operations.

Fortunately, private companies are to undertake much of the manufacturing — Larsen & Toubro (wings), Dynamatic Technologies (front fuselage), VEM Technologies (centre fuselage), and Alpha Design Technologies (rear fuselage). Hindustan Aeronautics Ltd. (HAL) will only undertake final assembly. As a result, the production rate of Tejas will increase to 24 aircraft a year. Importantly, this could help private industry acquire skills to become prime contractors and system integrators, and to someday make aircraft of their own design.

The Aeronautical Development Agency (ADA) undertook design work on Tejas, starting from zero previous experience, and did a commendable job of it. ADA had used advanced technology at every opportunity — advanced computational fluid dynamics for the aerodynamic design, a mock-up designed for the first time in India entirely on computer, advanced carbon fibre composite material for the structure, advanced avionics in the cockpit, and the like.

Kota Harinarayana, at that time programme director for the LCA, had once said that the control laws for the Tejas’ Flight Control System had been test-flown on a US F-16D test aircraft. He had quoted the test pilot as saying that the aircraft actually handled better with Tejas’ control laws. Indian test pilots have praised Tejas’ high-speed handling characteristics, its agility and have said it is easy to fly even at the limits of its operational flight envelope.

Admittedly, Tejas has some shortcomings, like having an inadequate payload/range performance, a high turnaround time between missions, being maintenance-intensive, and the like. Some of these should be addressed in Tejas Mk 2, which will hopefully be up to what is called fourth-generation technology standards. Thus, the Mk 1 and Mk 1A may serve, at best, as point-defence — rather than area defence — interceptors. They may not be adequate for the ground-attack role.

Some of Tejas’ design features are interesting. It is the world’s smallest single-seat, single-engine combat aircraft. It is of tailless, compound delta-wing design. A single-engine aircraft is roughly 30% cheaper to produce and operate than a twin-engine aircraft. However, to meet high performance requirements, particularly for the ground-attack role, twin-engine aircraft are preferred.

A small size reduces the flyaway as well as life-cycle costs. It also makes Tejas difficult to detect. However, it also reduces the vital payload/range performance. Analysts regard the larger SAAB Gripen as the smallest practicable multi-role aircraft. Having a single crewman reduces aircraft costs, but imposes a heavy workload on the pilot. That is countered with greater automation and computerisation in the cockpit.

Tejas is not designed for stealth. However, its small size, the high percentage of non-radar-reflecting composite material (about 45% by weight), and the Y-shaped bifurcated air intakes that prevent radar reflections from the engine’s fan blades, make Tejas difficult to detect – by radar or by unaided vision.

To avoid detection, Tejas can also minimise the use of its own active radar sensor and depend on its passive Infrared Search & Track (IRST) instead. Similarly, it will depend on its datalink for communication with friendly aircraft, rather than use its radio, which would give its position away. The datalink also helps in the exchange of data among friendly aircraft as well as from AWACS.

Need for reliable equipment

India was wrong to try to revive the indigenous Kaveri engine for Tejas. The General Electric F404 that replaced it is a tried and tested engine, in wide use globally. It also has good reliability and maintainability — particularly important for single-engine aircraft. Also, an export customer may not want the untried Kaveri.

Every major country needs to have indigenous defence equipment to protect itself, rather than depend on imported products. However, these need to be adequately developed. An unreliable product would place our armed forces at a disadvantage.

Tejas will have a wide range of weapons, including short-range and beyond visual range (BVR) air-to-air missiles, laser-guided bombs, glide bombs, cluster bombs, a 23-mm cannon, and the like. The Derby and R-73E missiles are “slaved” to the pilot’s helmet-mounted display and sight. To hit an enemy target, he merely has to look in the direction of the target and release the missile. The missile will do the rest.

Being a major importer of weapons, India is naturally keen to export indigenously developed ones. To date, Egypt, Sri Lanka, the UAE and Singapore have “shown interest”. Period. India should wait till the Mk 2 is in service and all its kinks are removed, before offering it. However, the trainer variant is not affected by the low payload/range performance of Tejas and could be offered earlier.

Tejas is likely to be further developed in the future, and to be upgraded with such developments as Direct Voice Control (through verbal signals to the sensors), an engine thrust vectoring nozzle (for greater agility in flight as well as for better runway performance), and hopefully a Variable Camber Wing (which will maintain high efficiency throughout its flight envelope), as well as a more advanced engine. With these developments, India’s aerospace defence industry will have come of age.

(The writer is an aerospace industry analyst) (The Billion Press)

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OPINION | How good is Tejas?

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