IIT Madras achieves breakthrough in vertical take-off, landing technology

Researchers at the Indian Institute of Technology, Madras, have achieved a breakthrough in developing a vertical take-off and landing (VTOL) aircraft and unmanned aerial vehicle (UAV) with hybrid rocket thrusters.

In a sophisticated experiment that combined a real-time hybrid rocket thruster with a virtual simulation, the researchers achieved the necessary velocity for ''soft landing'', a crucial feature for all craft ranging from planetary landing of an unmanned or manned exploration module to terrestrial landing of a VTOL aircraft, they added.

Touchdown velocity is an important parameter to ensure safe vertical landings.

The findings of the research were published in a paper in the reputed peer-reviewed International Journal of Aeronautical and Space Sciences.

The researchers studied the feasibility of using hybrid rocket motors for vertical landing platforms, as they are simpler and safer than liquid engines. Moreover, hybrid rocket systems are gaining popularity due to their inherent safety and throttling capabilities, apart from the possibility of combining the advantages of liquid and solid rocket engines.

Currently, VTOL systems are complex and require high maintenance. Therefore, the researchers conceived the concept of a hybrid rocket thruster-powered platform as part of a system development study to develop an effective propulsion unit for achieving VTOL in aircraft and UAVs.

According to PA Ramakrishna, professor at the Department of Aerospace Engineering, IIT Madras, VTOL enables an aircraft to take off and land vertically, eliminating the need for infrastructure like long runways.

''VTOL capability will enable access to remote locations and rugged terrains where long runways and large airports are difficult to establish. Currently, helicopters are the system operating on those terrains; however, they face limitations in terms of speed, range and efficiency compared to a fixed-wing aircraft,'' Ramakrishna said.

''Once the VTOL system reaches the Technology Readiness Level (TRL) for commercial application, it will be a game-changer in both civil and military aviation. VTOL will help to decentralise air transport to multiple locations rather than a single big airport or an airbase,'' he said.

Such decentralisation brings significant strategic and operational advantages, he said, adding that this study paves the way for the development and demonstration of a proof-of-concept for a hybrid rocket-powered VTOL platform.

Ramakrishna explained that, given the study's positive outcomes, an experimental study of the landing platform with multiple degrees of freedom could be conducted as a future study.

''Once attitude stabilisation (maintaining orientation in a desired direction) of the platform is achieved, a hardware-in-the-loop simulation for landing without the assumption of an attitude-stabilised system could be carried out. This would be a step closer to realising a VTOL platform with hybrid rocket thrusters,'' he said.

Attitude stabilisation of a VTOL platform is the process of maintaining orientation in a desired direction while hovering, taking off and landing.

The developed VTOL technology can be extended to fixed-wing UAVs as an initial implementation, he said.

This not only serves as a proof-of-concept for broader aerospace applications but could also attract attention from industries interested in next-generation air mobility solutions, he said.