Unmanned Systems Technology 001 | UAV Factory Penguin C | Real-time operating systems | Hirth S1218 two-stroke twin | Base stations | ASV C-Enduro | Composites | Datacomms

18 Dossier | UAV Factory Penguin C weight and aero drag. The Penguin’s wingspan has always been 3300 mm (while the craft is 2286 mm long excluding forward-facing pitot tube). Popiks notes that the size of the Penguin was set according to the weight of payload that it was considered desirable to carry – between 3 and 6 kg. “That allowed us to use a small engine – 28 cc, single-cylinder. We wanted a gasoline engine for long endurance. The combination of our engine and our payload capacity keeps us within 55 lb (25 kg), which is expected to be the FAA limit for simplified regulations for UAV operation. Although the FAA only governs the US, doubtless many other countries will follow its rules.” The maximum take-off weight of the Penguin C is 22 kg. Its general layout is straightforward, with the payload carried at the front of the fuselage and the engine mounted at the rear, so that the propeller pushes rather than pulls. The fuselage runs under the wing, which in turn also carries, via twin booms, an inverted-vee tail. Penguin C airframe The Penguin C’s airframe thus consists of the fuselage, the wing, tail section and the twin booms that connect it to the wing. The wing is in three sections and the booms are picked up by the inner section. Attached to the top of the fuselage, the inner section carries a flap each side while each outer section carries an aileron. The inverted-vee tail is in three sections, with the two sloping sides connected by a short right-angle top piece. Each side carries a pair of ‘ruddervators’ – flaps that combine the functions of a rudder and elevators. All the airframe components are made in-house, mostly using advanced composite construction (see sidebar: Advanced Composite Production at UAV Factory). The advanced composite fuselage is a pure monocoque, a load- bearing single-shell structure requiring no internal structural bulkheads. The 7.5 litre fuel tank and a firewall assembly fit tightly within its confines but are not designed to add to overall structural rigidity; they are part of an integrated power module, which is secured to the fuselage by only four lower bolts. The engine cowl is detachable from the rear of the fuselage, which is 288 mm wide and 202 mm high at its maximum cross-sectional area. The payload cover is secured by quick-release Dzus fasteners. Preparation of the fuselage includes the drilling of literally hundreds of holes, and special jigs have to be used to ensure the precise positioning of each one. The manufacturing of what is a superficially simple item is impressively sophisticated. The wing assembly is attached to the fuselage by only four bolts. The GPS module tracking the position of the aircraft sits atop the wing, in the middle, under a detachable cover. Across its 3300 mm wingspan, each of the three wing sections is of equal length. The precision of UAV Factory’s Preparing a Penguin C fuselage Penguin assembly at the UAV Factory – to the right, a worker attends to a ground station November 2014 | Unmanned Systems Technology