Performance and Stability Analysis of a Shrouded-Fan UAV

TL;DR

This paper presents models to estimate the performance and stability of a shrouded-fan UAV, accounting for complex aerodynamic interactions and ground effects, crucial for flight in ground effect scenarios.

Contribution

Developed two comprehensive models to evaluate aerodynamic coefficients and rotor thrust, incorporating fan-shroud interaction and ground effect for UAV stability analysis.

Findings

Performance varies significantly with flight conditions.

Ground effect substantially alters rotor thrust and aerodynamics.

Models effectively predict stability across different scenarios.

Abstract

This paper deals with the estimation of the performance and stability for a shrouded-fan unmanned rotorcraft whose mission profile also prescribes the flight in ground effect. The not so simple estimation of the aerodynamic coefficients and of the thrust in the various situations makes the performance calculation and the stability analysis difficult tasks. This is due to the strong interaction between the fan flow and shroud that causes quite different flow structures about the airframe depending on flight conditions. A further difficulty is related to the ground effect which produces substantial modifications in the rotor thrust and aerodynamic coefficients. To evaluate performance and stability, two models have been developed. One determines the aerodynamic coefficients of the shroud, whereas the other one calculates thrust and moment of the rotors system. Both models take into account the mutual interference between fan flow and fuselage and ground effect. Performance and stability are then discussed with reference to significant flight conditions.