The tab below will take you to a re-recording of Dr Brown's online lecture to the Bedford branch of the Royal Aeronautical Society, delivered on 9 March 2022.

In his lecture, Dr Brown examines our current understanding of the Vortex Ring State - a particularly hazardous operating regime that a rotorcraft can enter into during the critical descent and landing phases of flight.

He tells the story of how data from laboratory and numerical experiments was combined in the mid-'00s to change our understanding of the basic mechanisms at the heart of the phenomenon. As an illustration of how mathematical abstraction can lend deep insights into practical engineering problems, he then shows how a theory was developed that is now used throughout the world to help aircraft designers to understand the susceptibility of their creations to this potentially dangerous aerodynamic phenomenon.

Dr Brown ends the lecture by discussing the implications of his research for the next generation of helicopters and eVTOL aircraft that are about to come into service.