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

26 August/September 2017 | Unmanned Systems Technology Martin UAV V-Bat Fixed-wing tail-sitter UAS Wingspan: 2.75 m Length: 2.6 m Height: 0.76 m Maximum take-off weight: 37.2 kg Maximum payload weight: 3.2 kg Maximum airspeed: 90 knots (projected) Endurance limit: 8 hours (projected) Service ceiling: 4752 m Range (fuel limited): 560 km Range (telemetry): 50 km Engine: 183 cc, 15 hp, two-stroke twin-cylinder Twin-blade propeller Standard payload: EO/IR gimbal Data links: 900 MHz spread- spectrum two-way modem 2.4 GHz video downlink Sensors: synthetic aperture radar, short-wave infrared, signals intelligence, hyperspectral Mapping payload: digital SLR The V-Bat’s airframe is modular, with certain parts capable of being swapped and replaced depending on operational needs for weight, endurance or sensor type. The body consists of six parts – the ducted fan/tail section, the lower fuselage, left and right wings, upper fuselage and nose section. The body is built entirely in-house, and almost all of it is constructed using a carbon- Kevlar composite, from a wet lay-up into hard tooling moulds. A standard vacuum bagging process is then used to consolidate the materials. Each resulting section is constructed as a monocoque composite shell consisting of a carbon fibre skin over Kevlar hull and bulkheads, except for the wings. These are fibreglass and Kevlar over the entire surface with a balsa wood core, with carbon reinforcements in the leading, trailing and tip edges for robustness when handling the aircraft during pre-flight, take-off and landings. In addition, the outer hull also has a layer of fibreglass skin laid over it for its aesthetic qualities, while the carbon and Kevlar provide the structural integrity. When sitting vertically, the V-Bat rests on four coiled spring shock absorbers made from aluminium, steel or fibreglass, each one being fitted onto a tube strut that protrudes from the bottom of the duct. The engine sits inside the duct section, atop a carbon Kevlar motor mount for vibration isolation (with additional vibration isolators positioned ahead of the engine, facing the lower fuselage section above) with four carbon-Kevlar struts positioned symmetrically about the centre of roll, acting as support structures for the duct by connecting between the shroud and the upper part of the tail section. The tube struts run from the landing springs through these support structures, thereby assisting as the V-Bat lands in spreading the load upwards through the airframe body. This is a critical design feature for avoiding damage to the landing springs, the propeller and the control vanes. The engine directly drives the twin- blade propeller, which in turn sits beneath the motor mount, inside the Anatomy The V-Bat being put through its paces