21st Congress of International Council of the Aeronautical Sciences, Melbourne, Australia, 13-18 September, 1998
Paper ICAS-98-4.4.5

MANUFACTURING AND TESTING OF GRAPHITE-EPOXY WING BOX AND FUSELAGE STRUCTURES FOR A SOLARPOWERED UAV-HAVE

Romeo G.
Turin Polytechnical University, Italy

Keywords: graphite-epoxy wing box, fuselage structures, solarpowered, uav-have

The design of an automatic High Altitude Long Endurance (17-20 km) flying platform, capable of remaining aloft for very long periods of time, is presented. After that the vehicle should climb to 17 km by direct sun radiation, the level flight would be maintained by direct solar energy during the day and by a fuel cells energy storage system during the night. A computer program has been developed for carrying out a parametric study for the platform design, by taking into account solar radiation, latitude and altitude, mass and efficiency of solar cells and fuel cells, aerodynamics aspects, etc. A wide use of high modulus CFRP has been made in designing the structure in order to minimize the airframe weight. The final configuration of the platform is a monoplane, with 46 m of span, six brush less motors, twin-boom tail type and two rudders and TOGW of 6000 N. The platform is expected to cost about $ 3 million or 345 $ per hour of flight in one year. The design of a flying scale-sized technological demonstrator has been completed aiming to the realization of a proof-of-concept aircraft. The main wing box structure, two C-spar and two skin sandwich panels, has been manufacturing in three pieces, each one 8m long by using a graphite/epoxy pre-preg tape, and will be tested to shear -bending -torsion up to the ultimate load to verify the theoretical behaviour. A particular design has been. Developed for manufacturing fuselage and boom-tail; a very light pin-jointed CFRP truss-structure 3.6 m long has been manufacturing to carry the applied load. CFRP square tubes are bonded one to each other, by CFRP joints, to form up to seven connections. It will be tested under shear-bending load to show the correlation with the theoretical FEM analysis.

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