At the most fundamental level, main rotor loading noise is caused by the harmonically-varying aerodynamic loads (acoustic pressures) exerted by the rotating blades on the air. Rotorcraft main rotor noise is therefore, in principle, a function of rotor control inputs, and thus the forces and moments required to achieve steady, or “trim”, flight equilibrium. In certain flight conditions, the ensu...

The paper presents the results of simulation unsteady turbulent flow generated by helicopter main rotor in presence fuselage with an emphasis on analysis influence rotor-induced and rotor-generated acoustic field. Reynolds-averaged Navier–Stokes equations Spalart–Allmaras turbulence model are used to simulate Caradonna–Tung ROBIN interaction hovering flight. governing discretized using vertex-c...

The Autonomous UAV Technologies Laboratory 1 at Linköping University, Sweden, has been developing fully autonomous rotor-based UAV systems in the miniand micro-UAV class. Our current system design is the result of an evolutionary process based on many years of developing, testing and maintaining sophisticated UAV systems. In particular, we have used the Yamaha RMAX helicopter platform (Fig. 1) ...

The integrity of bonded structures is of paramount importance in the safe and reliable operation of aircraft equipment. Fuselages, helicopter rotor blades and nose cones are multilayered composite structures bonded together. The operational readiness and security of these units depend to a large extent on the integrity of the interfacial bonds. Adhesive and cohesive strength studies do not appe...

Experimental Hardware The installation of two side-arm mounted, isometric controllers in the NAE Airborne Simulator, a modified, variable stability Bell 205’A is described, as is the development of various control systems for use with them. The results of two experiments are presented indicating both the feasibility and acceptability of such systems for a wide variety of tasks in a conventional...

A Tagaki-Sugeno fuzzy model of a six degrees of freedom, four-rotor helicopter is presented. For this model, a state-feedback parallel distributed compensator is designed using a LMI optimization algorithm to ensure stability conditions. Stabilization over translational and angular coordinates is achieved. The simulations were performed without considering the effect of parametric uncertainties...

A time-accurate procedure to model fluid/structure interactions of helicopter blades is presented. The Navier-Stokes equations in conjunction with the one-equation SpalartAllmaras turbulence model are used to compute the flow. Structural dynamics is modeled using the modal equations. The aerodynamic and structural dynamic equations are coupled time-accurately using the linear acceleration metho...