Missile I-Derby ER

The I-Derby ER is an evolution of the Derby beyond-visual-range missile, which was itself derived from the Python-4 air-to-air system. Development of this variant was confirmed in June 2015 following the abandonment of a separate project based on the Stunner missile.

The missile utilizes active radar homing for guidance. It is powered by a dual-pulse solid rocket motor designed to increase operational reach. This propulsion system employs a secondary energy pulse that activates during the terminal phase as the missile approaches the target, extending flight time. To optimize internal space for the motor, the missile incorporates an integrated sensor and fusing system that combines these components into a single assembly.

The system has been selected for the Indian Air Force for use on the Tejas fighter. Plans were also established in 2019 to integrate the missile onto Su-30MKI aircraft to replace R-77 inventories. The Czechia is scheduled to receive the missile by 2027.