IIT Madras Develops Bird-Inspired Morphing Skin to Prevent Aircraft Stalls

Researchers at the Indian Institute of Technology Madras (IIT Madras) have developed a bird-inspired “morphing skin” for aircraft wings that can adjust its shape according to changing airflow conditions. The technology is designed to reduce the risk of aerodynamic stalls while increasing lift, lowering drag and potentially improving fuel efficiency.

The research was led by Dr Rinku Mukherjee, with IIT Madras alumnus Antony Samuel B contributing to the numerical code and Dr Aritras Roy involved in wind tunnel experiments and implementation.

An aerodynamic stall occurs when airflow separates from an aircraft wing, causing a sudden reduction in lift and an increase in drag. To address this, the IIT Madras team developed a flexible external wing attachment that can change its shape as airflow begins to separate from the wing surface.

The adaptive skin responds to airflow and adjusts its alignment to help maintain attached airflow over the wing. This could allow an aircraft to retain lift at higher tilt angles and improve its aerodynamic stability in challenging flight conditions.

The system uses Macro Fibre Composite (MFC) strips that enable the wing attachment to sense and produce shape changes in real time. According to Mukherjee, aircraft naturally tilt during takeoff to generate enough force to leave the ground, while unexpected changes in flight conditions can also alter the aircraft’s tilt. The external wing assembly is designed to adjust itself within a safer range and continue generating additional lift.

The research has been in development for more than two decades. The work evolved from studying separated airflow to creating and experimentally testing a physical device capable of influencing aerodynamic properties in real time.

The researchers tested the concept on a three-dimensional wing based on the standard NACA 4415 airfoil configuration. Initial findings indicated that the morphing skin could delay or prevent airflow separation, increase lift and minimise drag.

The research findings were published in the European Journal of Mechanics, with Dr Rinku Mukherjee and Dr Aritras Roy listed as co-authors.

The latest development adds to IIT Madras’ long-running research into adaptive aircraft technologies. Under the Morphing Wing Aircraft Technologies (MWAT) project, funded by the Defence Research and Development Organisation (DRDO), researchers studied a rectangular wing capable of changing its camber during flight. The project, conducted from 2017 to 2022, included numerical analysis, experimental studies and wind tunnel testing, with an MFC-actuated external skin used to demonstrate changes in wing camber.

Another DRDO-funded project carried out between 2015 and 2017 examined the unsteady aerodynamics of a pitching wing. Researchers developed numerical methods for studying aerodynamic behaviour before and after stall conditions and established experimental facilities for measuring pressure and aerodynamic loads.

An earlier project conducted between 2010 and 2012 focused on predicting the two-dimensional and three-dimensional aerodynamic characteristics of unsteady post-stall airflow.

Together, these research efforts reflect IIT Madras’ continued work on aircraft aerodynamics, morphing wing technologies and adaptive systems designed to improve flight performance, control and safety.