eZoneToday

---

India’s Tejas MK1 fighter Jet:How homegrown engineering created the world’s lightest, multi-role supersonic fighter.

---

For decades, the Indian Air Force (IAF) relied heavily on foreign imports for its fighter fleet. The dream of a truly indigenous fighter jet seemed distant, riddled with technological hurdles and skepticism. Enter the Tejas LCA (Light Combat Aircraft).

Named “Tejas” (meaning ‘Radiance’ or ‘Brilliance’ in Sanskrit) by former Prime Minister Atal Bihari Vajpayee, this delta-winged fighter is more than just a machine; it is a statement of India’s growing technological prowess. It is designed to replace aging legends like the MiG-21 and serve as the backbone of the IAF’s future combat capability.

The Tejas Light Combat Aircraft (LCA) project was initiated by the Indian government in 1983, with the formal establishment of the Aeronautical Development Agency (ADA) in 1984 to manage it, aiming to replace aging MiG-21s; the aircraft was officially named Tejas by Prime Minister Atal Bihari Vajpayee in 2003.

In this post, we’re unveiling the intricacies of this agile jet, showcasing its cutting-edge design, the advanced technology powering it, and the formidable arsenal it boasts for combat.

The Design Philosophy: Unstable by Choice

The defining characteristic of the Tejas is that it is a 4.5-generation, multi-role, supersonic fighter. But what makes it unique is its size. The Tejas holds the distinction of being the smallest and lightest combat aircraft in its class globally.

To achieve extreme maneuverability, the designers at the Aeronautical Development Agency (ADA) made a bold choice: they designed the aircraft to be aerodynamically unstable, a concept known as Relaxed Static Stability (RSS).

Imagine trying to balance a pencil on its tip; it wants to fall. The Tejas wants to change direction constantly. This inherent instability allows for incredibly fast turns and agile dogfighting capabilities, but it makes the jet impossible for a human to fly manually. The solution? Advanced computing.

The Fuselage and Wing design of Tejas Mk1

The visual signature of the Tejas is its compound tailless delta-wing configuration.

• Delta Wing: A delta wing is an aircraft wing planform shaped like a triangle. Its name comes from its resemblance to the Greek uppercase letter delta (Δ). This design is associated with high-speed aircraft, such as supersonic jets, due to its aerodynamic characteristics. The large, triangular surface provides structural advantages, allowing for a strong and lightweight wing. Delta wings allow for better maneuverability and stability at high angles of attack, which is particularly advantageous in fighter
• Tailless: The Tejas features a tailless design, meaning it does not have horizontal tailplanes at the rear of the aircraft. This innovative approach helps in reducing aerodynamic drag, which can enhance speed and fuel efficiency. Additionally, by eliminating these tail surfaces, the aircraft presents a lower radar signature, making it somewhat more challenging for enemy radar systems to detect and track, thus improving its stealth capabilities(eventhough it Tejas is not categorised as stealth). This design choice contributes both to the fighter’s agility and its survivability in combat scenarios.
• Composite Material:  Delta Wing fighter is constructed of aluminium-lithium alloys, carbon-fibre composites, and titanium alloys. Composite materials make up 45% of the airframe by weight and 95% by surface area. Upper and lower wing skins are manufactured from a single piece of carbon-fibre reinforced polymer. Wing spars and ribs are also made out of carbon composites. This material is lighter than aluminum but five times stronger than steel, contributing significantly to its high thrust-to-weight ratio and reducing the number of joints, which increases structural integrity.

The Brain of Tejus: Key Technologies Used

Because the aircraft is inherently unstable, it relies on a “digital nervous system” to stay in the air.

Quadruple-Redundant Fly-by-Wire (FBW)

Fly-by-Wire (FBW) is an electronic flight control system in aircraft that replaces traditional mechanical linkages (cables, pulleys, rods) with electrical signals, using computers to process pilot inputs and move control surfaces.The pilot doesn’t move the control surfaces directly. The pilot tells the computer what they want to do, and four independent flight control computers instantly calculate and execute the necessary adjustments to the flaps and rudder to keep the plane stable while performing the maneuver. “Quadruple redundant” means if one, two, or even three computers fail, the jet can still fly.

Tejas LCA Cockpit and Avionics

Gone are the days of confusing analog dials. The Tejas cockpit is dominated by Multi-Function Displays (MFDs)—large screens that provide navigation, weapon status, and radar data at a glance.

The Tejas aircraft features a night vision goggles (NVG)-compatible glass cockpit, equipped with a domestically developed head-up display (HUD) designed by the Central Scientific Instruments Organization (CSIO). It includes three 5-inch by 5-inch multi-function displays, two Smart Standby Display Units (SSDU), and a “get-you-home” panel featuring a fail-operational/fail-safe air data computer (ADC) manufactured by Bharat Electronics Limited (BEL). This ADC incorporates a computational intelligence-based autoland system that provides essential flight information to the pilot during emergencies, and is integrated with the Indian Air Force (IAF) ground station network to enable emergency control of the aircraft if necessary. The displays present critical information regarding flight systems, controls, and tactical data on a need-to-know basis.

The Radars Used in Tejas Mk1

The initial Tejas Mk1 variants use a hybrid Israeli EL/M-2032 multi-mode radar.The ELM-2032 is an advanced multimode airborne Fire Control Radar (FCR) designed by ELTA Systems Ltd, part of Israel Aerospace Industries. This sophisticated radar system is tailored for multi-mission fighters, supporting a diverse range of operational demands including air-to-air, air-to-sea, and strike missions. 

A fire-control radar (FCR) is a radar that is designed specifically to provide information (mainly target angle, elevation, and range) to a fire-control system in order to direct weapons such that they hit a target.

Key features of the ELM-2032 include Pulse Doppler technology, all-aspect look-down shoot-down capabilities, and a low sidelobe planar antenna. It also boasts a Monopulse and guard channels, a Programmable Signal Processor (PSP), and compatibility with all avionic interfaces

However, the game-changer is the upcoming Uttam AESA Radar. The Uttam AESA (Active Electronically Scanned Array) radar, developed by India’s Defence Research and Development Organisation (DRDO) is a fully indigenous Active Electronically Scanned Array radar. Unlike older mechanical radars that physical turn to scan, AESA radars scan electronically, allowing them to track dozens of targets simultaneously across air, land, and sea, while being much harder to jam.

In a recent interview Dr. Samir V. Kamat, Chairman of Defence Research & Development and Chairman of the Defence Research and Development Organisation (DRDO) ,has confirmed that “plan is to integrate the Uttam AESA radar starting from the 41st Tejas Mk1A jet”

The Heart of Tejas MK1 Jet: The Engine

An indigenous jet needs an indigenous engine. India began developing the “Kaveri” engine for the Tejas. Unfortunately, jet engine technology is notoriously difficult to master, and the Kaveri program faced significant delays in meeting the required thrust parameters.

To ensure the Tejas entered service without further delay, India selected a proven, reliable international alternative.

• Current Engine: The Tejas Mk1 is powered by the American General Electric F404-GE-IN20 turbofan engine. It is reliable, powerful enough to push the light airframe past Mach 1.6, and has a good operational history.
• Future Engine: Future, larger variants of the Tejas (like the Mk2) will likely use the more powerful GE F414 engine.

Arms Deployed on Tejas

Don’t let its small size fool you; the Tejas is a “bomb truck.” It has 8 hardpoints (stations to attach weapons) under the wings and fuselage, capable of carrying over 4,000 kg of payload. It is a true multi-role fighter, meaning it can switch from air-to-air combat to ground attack in the same mission.

• Air-to-Air Missiles (AAM):
  • Beyond Visual Range (BVR): It currently deploys the Israeli Derby missile. Crucially, it is being integrated with India’s indigenous Astra BVR missile, a massive step toward self-reliance.
  • Close Combat: The Russian R-73 and Israeli Python-5 (one of the most advanced heat-seeking missiles in the world) handle dogfights.
• Air-to-Ground:
  • Laser-guided bombs (LGBs), unguided bombs, and cluster weapons for ground targets.
• Anti-Ship:
  • Capable of carrying specialized missiles to engage maritime targets.
• The Gun:
  • A twin-barrel GSh-23 23mm cannon for close-quarters engagements.

The Road Ahead: Future Plans

The Tejas Mk1 currently flying is just the beginning of the ecosystem.

Tejas Mk1A:This is the immediate successor currently entering production. It fixes the minor shortcomings of the Mk1. Key upgrades include:

• The indigenous Uttam AESA radar.
• An advanced Electronic Warfare (EW) suite designed in India to jam enemy radars.
• Mid-air refueling capability to extend range.
• Easier maintenance.

Tejas Mk2 (Medium Weight Fighter):This will be a significantly different beast. The Mk2 will be larger, heavier, and more powerful (using the GE F414 engine). It will feature “canards” (small winglets near the cockpit) for even better maneuverability and increased payload capability. It is designed to replace aircraft like the Mirage 2000 and Jaguar.

AMCA (Advanced Medium Combat Aircraft):While not strictly a “Tejas,” the experience gained from the Tejas program is directly fueling India’s 5th-generation stealth fighter project, the AMCA.

Performance and range of Tejas Mk1,Tejas Mk1A and Tejas Mk2

The path of the Tejas was long and often criticized for delays. But today, as squadrons of these delta wings patrol Indian skies, they represent a monumental achievement. The Tejas proved that India could master fly-by-wire technology, composite airframes, and complex avionics integration. It is an agile, capable, and evolving platform that has secured India’s place at the high table of military aviation manufacturers.