India's TEJAS MK-1A fighter jet represents a remarkable leap in aerospace engineering through its extensive use of carbon-fibre reinforced composites—a strategic decision rooted in decades of innovation and operational necessity.

Over 90% of the TEJAS's visible surface is made from advanced composites, with approximately 45% of its structural weight comprised of these materials. This is one of the highest composites-to-surface ratios of any frontline fighter jet globally, surpassing many advanced Western fighters, which typically feature far lower proportions of composites.

Why Use Over 90% Composite Skin?

The choice to make such a large fraction of the TEJAS’s skin and structure from composites arises from several critical performance and operational imperatives:

Weight Reduction: Compared to traditional aluminium or titanium alloys, carbon-fibre composites are dramatically lighter for the same strength, reducing the overall airframe weight by about 21–25%. This weight saving is crucial for a single-engine aircraft, allowing the TEJAS to achieve higher agility, longer operational range, greater fuel efficiency, and an increased payload capacity.

Structural Efficiency: Carbon-fibre composites provide superior strength and stiffness relative to their weight, outclassing both steel and aluminium. This enables designers to create components that withstand immense aerodynamic loads while keeping the aircraft nimble and robust. Structural elements such as wing skins, spars, ribs, fin, and large sections of the fuselage are fashioned from these advanced composites, enhancing the aircraft’s structural efficiency and durability.

Reduced Part Count And Fatigue: The process of moulding composites enables the fabrication of complex, monolithic (single-piece) components, which drastically reduces the number of joints, fasteners, and rivets compared to metallic construction. This not only cuts maintenance demands but also improves resistance to fatigue and structural cracks over the aircraft’s lifespan.

Corrosion Resistance: Unlike metals, carbon-fibre composites are innately resistant to corrosion and do not rust. This trait is vital for fighter jets operating from coastal bases or under humid, saline conditions, extending the TEJAS’s operational longevity and reducing upkeep.

Stealth And Radar Cross-Section (RCS): Composites, especially carbon-fibre, possess favourable electromagnetic properties that scatter and absorb radar waves, thus lowering the jet's radar cross-section. While TEJAS was not designed as a stealth fighter, the extensive composite skin makes it harder to detect than most comparable non-stealthy fighter aircraft—a significant tactical advantage in modern aerial warfare.

Manufacturing Advances: Indian companies such as Hindustan Aeronautics Limited (HAL) and L&T have mastered cutting-edge composite manufacturing techniques, including automated fibre placement and autoclave curing. These processes create high-strength, almost void-free structures that conform precisely to aerodynamic requirements, while non-destructive testing ensures uncompromised quality and safety.


What Makes These Composites Tough And Light?

High Strength-to-Weight Ratio: Carbon-fibre composites are made by layering woven carbon fibre fabric, impregnated with resins (like epoxy or bismaleimide), and cured in high-pressure, high-temperature environments. This yields panels and airframe parts that are several times stronger per kilogram than steel or aluminium, without the associated mass penalty.

Fatigue And Temperature Resistance: These materials retain their mechanical properties even after millions of operational cycles. Special high-temperature resistant variants—developed for critical zones such as engine bay doors—can withstand up to 200°C, a feat difficult for conventional materials at similar weights.

Customisation And Integrity: By controlling the orientation of carbon fibres, engineers tailor strength and stiffness to specific loads, resulting in optimized, highly resilient components with minimal excess mass. The monolithic nature of key parts also enhances resistance to impact and delamination, ensuring toughness in demanding flight scenarios.

Additional Benefits

Simplified Maintenance: Damaged panels can often be replaced modularly without invasive structural repairs.

Design Flexibility: Composites can be moulded into complex aerodynamic shapes that would be difficult, heavy, or expensive to replicate with metals.

In sum, the TEJAS MK-1A leverages the full spectrum of advanced carbon-fibre composite benefits to produce a fighter that is lighter, tougher, and stealthier than would be possible with traditional metals. This approach provides tactical and operational advantages, setting a new benchmark in military aviation materials science.

IDN (With Inputs From WION)