Originally an engineer and aerodynamicist, McEwan was invited by Sir Geoffrey Taylor to collaborate in pioneering studies in electrohydrodynamics and in viscous free surface phenomena. Fundamental work on rotating fluids turned his interest towards geophysical problems. He has devised and conducted laboratory experiments on processes of the atmosphere and ocean as diverse as fronts, waves, convection, stratified and rotating flows, and the quasi-biennial oscillation. His special ability has been to produce simple abstractions of complex real-world situations, capable of innovative experimental and mathematical investigation. Both of these have been pursued at high scientific level, revealing new phenomena and providing new understanding of the complex geophysical dynamics. His work is characterised by an interactive blend of mathematical and physical insights which give his investigations a totality and scientific unity very rarely achieved by one individual.