Unmanned Systems Technology 025 | iXblue DriX I Maintenance I UGVs I IDEX 2019 I Planck Aero Shearwater I Sky Power hybrid system I Delph Dynamics RH4 I GCSs I StreetDrone Twizy I Oceanology Americas 2019

23 of them,” says Eudeline, a former officer in the French Navy with a background that encompasses engineering as well as tactical operations. Hydrodynamics One of the first configuration decisions concerned the hull form. V-shaped hulls are common in manned vessels because they provide the internal volume needed to accommodate a crew, but they do not have the most hydrodynamically efficient cross-section. That was important, because iXblue wanted a vehicle that would present the propulsion system with minimum resistance so that it could combine usefully high speed with frugal fuel consumption, while allowing the engine to devote a major portion of its power to generating electricity for onboard equipment. This pursuit of ‘slippery’ hydrodynamics led to a slim hull form that combines the DriX’s 7.7 m length with a beam of 0.7 m at its widest point, giving a fineness ratio (the ratio of the length of a body to its maximum width) of 11:1. That is a figure that wouldn’t disgrace a racing catamaran, and is unusual for a small monohull surface vessel but which Eudeline says is ideal for minimising fuel consumption. This presented an integration challenge in terms of the volume and weight available for equipment inside the narrow hull. The hull is terminated at the front by a sharp reverse bow, a wave-piercing shape reminiscent of early 20th-century dreadnought battleships and the US Navy’s iXblue DriX | Dossier Unmanned Systems Technology | April/May 2019 Quiet confidence