DESIGN OF A PROTOTYPE UNMANNED LIGHTER-THAN-AIR PLATFORM FOR REMOTE SENSING: STRUCTURAL DESIGN AND OPTIMIZATION

This work presents the structural design of a new Remotely Piloted Aircraft System (RPAS) concept for land survey applications. The RPAS Lighter-Than-Air (LTA) platform is equipped with a thrust vectoring control system made of six propellers attached to a single-rib exoskeletal load-bearing structure. The load-bearing structure is optimized to minimize structural mass, maximize payload capability, and meet the airship's operational requirements. A finite element model of the load-bearing structure was developed and analyzed under normal operating conditions of the airship, such as mid-air hovering and parking. Additionally, various failure cases, such as crash landing and control system failure, leading to haphazard operation of the propellers, were considered to simulate extreme load conditions on the airship exoskeletal structure. Airship slenderness was also considered an important design parameter and was optimized to maximize aerodynamic performance. A twin paper describes the other non-structural aspects of the airship design.