Unmanned Systems Technology 015 | Martin UAV V-Bat | William Sachiti | Sonar Systems | USVs | Desert Aircraft DA150 EFI | SeaCat AUV/ROV | Gimbals

were virtually unheard of though. As Jones notes, “We’re reasonably confident that we might not even need the skid, and if that’s the case then it’s really just a source of unnecessary drag. So we’ll either redesign it into more of an aerofoil shape or, as with the ailerons, consider removing it entirely.” Powertrain In addition to keeping the propeller and surrounding objects safe, reducing drag and providing improved control authority over the craft, the duct cowling also provides cooling air for the engine. Most of the air for the system is pulled in from the sides of the shroud, over the lip of the duct, and is then filtered and forced through the engine. The engine used in the present aircraft model is an unmodified Hirth 4201. The engineering team may opt to change the engine at a future date, to reduce the acoustic signature or improve the fuel economy at certain flight stages, but in every test so far the Hirth’s performance has been satisfactory, Jones says. The 4201 is a two-stroke, twin-cylinder 15 hp boxer model with electronic fuel injection. Current acoustic damping comes from twin mufflers, each connected to one of the horizontally opposed cylinders. As with Hirth’s other two-stroke engines, the direct injection system uses the company’s iPower technology. Here, the fuel (either gasoline or JP-8 kerosene for the V-Bat) is injected on a time-dependent basis into a resonance tube, which connects with each cylinder for intake of hot exhaust gases under pressure from combustion. The combination of hover control and a protective shroud means technicians can safely walk up to an inbound V-Bat and manually ease it onto the ground