Nimbus Meta-plane, a New Aerodynamic Concept for Unmanned Hybrid Aerial Vehicle Application 2008-01-2243

The work attains a new hybrid concept of a light unmanned aerial vehicle, called “Nimbus”, based on an inflatable lifting body which combines the characteristics and the performances of Lighter-Than-Air and Heavy-Than-Air platforms. This hybrid design allows short take off and landing (STOL) capability due to its low wing loading, absolute stability reference, good employable payload capacity, high endurance, no runway or ground handling system requirements and easy piloting. The inflatable wing is a cylindrical pneumatic chamber, light weight, V shaped and filled with helium. The main aim of the paper is to describe the approach followed in the preliminary design of the Nimbus platform supported by evidences provided by both CFD simulations and experimental trials of a model prototype. The numerical simulations are performed in order to characterize the near flow field on the blimp lifting body balloon and to estimate the main performances of the aerial vehicle. Flight tests are performed by a model prototype demonstrating the goodness of the preliminary theoretical analysis. A complete system performance overview is reported, covering all main technical features needed to describe possible mission applications. Mission flexibility of the Nimbus aerial vehicle and possible future developments are briefly outlined.