India is pursuing a sophisticated multi‑layered infrared stealth program aimed at reducing the detectability of its future combat aircraft across both the mid‑wave (3–5 μm) and long‑wave (8–14 μm) infrared bands. This initiative reflects the necessity to survive against evolving IRST systems and imaging seekers deployed by advanced adversaries in contested airspace.

The exhaust plume remains the most intense and conspicuous thermal signature, particularly in the mid‑wave band. To counter this, Indian designers are integrating advanced mixing techniques that blend cooler bypass or ambient air with the hot core flow, significantly lowering apparent plume temperature.

Serrated or chevron nozzles, variable ejector‑type mixers, and divergent‑flap configurations are being applied to enhance plume mixing efficiency and reduce IR brightness from rear‑aspect views.

In parallel, chemical suppression methods are under research to alter the emissive characteristics of combustion gases. Fuel‑borne additives and controlled injection of coolant vapours can adjust the plume’s chemical composition, lowering emissivity across seeker‑sensitive wavelengths.

Trials with partially combusted vapour streams also show promise in producing “colder” exhaust patterns, effectively blunting missile seeker tracking and IRST lock‑on capability.

Attention is also directed toward minimising the aircraft’s skin radiation within the long‑wave spectrum. India’s laboratories are developing IR‑absorptive and low‑emissivity surface coatings that scatter or dissipate heat radiated from internal subsystems, avionics, and aerodynamic friction heating.

These paints and composites help reduce thermal contrast from side and frontal aspects, protecting the aircraft from wide‑angle IR sensor arrays and ground‑based surveillance networks.

Application On TEJAS MK-2, AMCA, And UCAVs

India’s multi-pronged IR stealth approach is being integrated and trialled on new-generation platforms, most notably the TEJAS MK-2, Advanced Medium Combat Aircraft (AMCA), and future unmanned combat aerial vehicles (UCAVs). These platforms represent the spearhead of indigenous fighter development under HAL and DRDO stewardship.

For TEJAS MK-2, engineers are optimising the engine exhaust geometry: serrated nozzle flaps and advanced bypass-air mixing systems have been incorporated to curtail thermal spikes during extended supersonic operations. Initial flight trials have demonstrated measurable reductions in rear-aspect IR contrast, increasing survivability against missile threats equipped with imaging seekers.

The AMCA, as a fifth-generation design, integrates comprehensive IR suppression from concept stage. Its S-shaped intake and deeply shielded core engine configuration limit direct line-of-sight to hot components.

The airframe is being coated with proprietary IR-suppressant composites, and self-healing paints that scatter long-wave radiation effectively, countering both airborne IRST and advanced ground-based IR sensors. Early prototypes also feature experimental chemical injectors to fine-tune exhaust emissivity in real time, drawing on flexible fuel-additive technologies.

DRDO and private sector partners are extending these measures to indigenous UCAVs, with smart nozzle shaping, dual-mode mixing, and modular surface lattice coatings being trialled for optimised stealth during deep penetration and surveillance tasks. These UCAVs use lightweight IR-resistant materials around critical heat sources, minimising hot spot formation that adversarial sensors exploit.

Collectively, these applications across TEJAS MK-2, AMCA, and UCAV programs highlight India’s shift toward integrated, all-band IR stealth as a core capability. The result is a marked reduction in platform vulnerability during ‘Day-Zero’ operations and intense electronic/missile threats, directly enhancing operational flexibility and air dominance within Asia’s contested environments.

Together, these advances demonstrate India’s determination to achieve comprehensive IR signature management across all sensor bands.

By addressing both exhaust and skin contributions, future indigenous fighters and UCAVs are expected to operate with markedly reduced detectability, strengthening survivability and mission success in heavily contested theatres.

IDN (With Agency Inputs)