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22 In conversation | Jean-Claude Tourn Heat management One of the most challenging aspects, Tourn says, was the design of the hot line ducts from the jet engine to the exhaust nozzles via the rotating bifurcation. That meant splitting the jet exhaust stream into two and feeding it reliably and efficiently to nozzles at the tips of the rotating arms. The other was ensuring a smooth and tight connection between the engine exhaust and the rotating bifurcation. The materials used for the components in this system changed several times, from stainless steel to Inconel and then to the ceramic matrix composite used now. Key flight test milestones achieved so far include stable take-off and landing, stable hover, elimination of vibration and resonance problems, and what Tourn calls perfect response in pitch, roll and yaw. Still to come are testing for speed and altitude performance, crosswind response and crashworthiness. The aircraft has also grown with each new iteration. The original E Yo 200-05 had a take-off weight of 100 kg and a 45 kg payload; the current E Yo 550-01 takes off at up to 280 kg and carries up to 200 kg in payload. There is an even larger vehicle planned. The E Yo 1.000 has a projected take-off weight of 565 kg and a 450 kg payload, and will be powered by JetCat’s upcoming P1000. What’s in a name? The vehicle’s unusual name originated in the search for an appropriate one that hadn’t already been used. Tourn wanted to call it Scarabeo (scarab) at first, honouring the dung beetle that can carry the largest payload in the insect kingdom, but there are many products that already use this name, mainly scooters and motorcycles. Then he wanted to call it Herakles, but for this kind of application the name was already registered to Safran. His third choice was Heli-Lift, which served for several years during development while he was searching for something better. The current name was inspired by the electronic yaw control system. The E Yo Copter needs very little power for yaw control because the rotor generates no torque reaction to turn the fuselage in the opposite direction. In fact, slight drag between the rotating and stationary elements of the exhaust seal cause the fuselage to rotate slowly in the same direction as the rotor, which is countered by an electric thruster or, ingeniously, by a small integral torque motor. The name was to have been E Yaw Copter, but that wouldn’t quite do either. “Then I found on the internet thousands of people called E Yaw in Asia, so I changed it to E Yo Copter, and it has had a very good reception,” Tourn says. Its similarity to the lugubrious Eeyore from the Winnie the Pooh stories hadn’t occurred to Tourn, but it amused him when I pointed it out. It seems appropriate for a beast of burden. February/March 2018 | Unmanned Systems Technology Tourn is the president of E Yo Copter, the company he formed to develop an unmanned flying crane after having witnessed the effects of the 2004 tsunami in Sumatra. Educated at the Lycee Carnot in Cannes and the Faculté de Droit Nice, he earned a qualification in business administration from the Institut d’Administration des Entreprises. A lawyer and businessman by background, he ran marketing, licencing and acquisition operations for haute couture companies and Paris fashion houses Mendes/Jean-Patou, Georges Rech and Group Guy Laroche for almost 30 years. Flying is a lifelong passion, and he became involved in aerospace engineering through his friendship with Jean Soulez Lariviere, inventor of a canard tilt-rotor aircraft. Jean-Claude Tourn Joining two or three E Yo Copter modules together could create a multi-copter system with greater lift capabilities, an idea that manned helicopter designers have explored in the past