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21 In 1981, he entered Exeter College at Oxford University to begin his undergraduate degree, in zoology, eventually becoming professor of biomechanics in Oxford’s zoology department. “Zoology was my first degree, but my PhD was on the aerodynamics of bird tails, and was jointly supervised by the departments of theoretical ecology and aeronautical engineering at Lund University [in Sweden],” he says. “I’ve always transitioned between aerodynamics and hydrodynamics: it’s just a difference in fluid densities.” Malolo In January 2015, Prof Thomas and entrepreneur Alex Caccia founded Animal Dynamics, after having already done a lot of work on developing Prof Thomas’ ideas on underwater propulsion. This propulsion project, called Malolo, was initiated in 2014, and its first working prototype went active in October that year. Malolo now consists of an array of demonstrators aimed at achieving considerable benefits in hydrodynamic and energy efficiency. Most recently, Animal Dynamics received InnovateUK funding to perform a Phase 1 Feasibility Study of the Malolo systems, with the agency splitting the demonstrators into two classes. One, based on skates and rays, is for efficiently cruising around seabeds as well as setting down and relaunching without becoming clogged by seaweed, as can happen with propellers. “In that class, our Malolo ‘rays’ integrate two tail-drives with high gearing to mimic the angle of attack and waveform typical of manta ray fins, since mantas swim with a cruise efficiency of well over 90%,” Prof Thomas notes. “We’ve created a lot of different drive systems and designs to replicate the movement of various fish and sea mammals, with tuna perhaps being the one we’ve studied the most. Tuna are everywhere, so there must be a reason why they’re so evolutionarily successful.” The other class consists of long- endurance, high-efficiency designs that were found to use around 20% less energy than propellers, which the professor notes could be useful for shipping. Since freighter component companies such as Rolls-Royce work on orders going back roughly 25 years, however, he does not anticipate this class being a future direction for the Malolo systems. The Skeeter The Malolo project was put on hold between 2015 and mid-2019, as Animal Dynamics received funding from the UK government’s Defence Science and Technology Laboratory to pursue Skeeter, a new project centred on aerial biomechanics, and inspired by studies of dragonfly wing lift. “By then we’d investigated a huge range of airborne animals, and how their shapes and movements contribute to how they work. Dragonflies were an easy choice because you can throw a dead dragonfly and it’ll glide effectively – there’s a great Japanese study where researchers essentially just threw a bunch of them into the air to calculate their lift-to-drag ratio,” Prof Thomas says. “When wings fly that well without a living brain controlling them, it takes away much of the problem of how to design an effective control system, so it made sense to engineer dragonfly-based propulsion before, say, birds or bats.” The Skeeter therefore has a four-wing design – two each on its left and right – which are timed so that the forward wings flap out of phase with the rear wings (although each left-hand one Adrian Thomas | In conversation Unmanned Systems Technology | October/November 2020 The Stork UAV’s parafoil flight has been inspired by Prof Thomas’ studies of hydrostatic skeletons in nature, as well as his successes in the British National Paragliding Championships