Preliminary reliability design of a solar-powered high-altitude very long endurance unmanned air vehicle

Abstract

Within the research project HELINET (network of stratospheric platforms for traffic monitoring, environmental surveillance and broadband services), a preliminary reliability design is performed in conjunction with the platform design. The aim of the discussion consists in determining the configuration of the propulsion system and in the choice of the number of propulsion units (a propulsion unit consists of one propeller and one or more motors). The reliability and the weight of different very simple systems are evaluated and compared with one another in order to indicate the best one. The analysis of the fleet reliability and a study of its standby platforms is also taken into consideration. The analysis of the reliability of the solar cell array is also an interesting issue. A parametric analysis based on well-known formulae is used. Some results are verified by means of a numerical simulation based on the Monte Carlo methodology. Some important design indications could be obtained from this effort.