Rotorcraft thickness noise control by tip ventilation

Synergistic Noise-By-Flow Control Design of Blade-Tip in Axial Fans: Experimental Investigation

Differential Flat Control for Rotorcraft Trajectory Tracking

The purpose of this communication is to investigate the usefulness of the differential flatness control approach to solve the trajectory tracking problem for a four rotor aircraft. After introducing simplifying assumptions, the flight dynamics equations for the four rotor aircraft are considered. A trajectory tracking control structure based on a two layer non linear approach is then proposed. ...

AIAA 2000–2031 Noise Prediction For Maneuvering Rotorcraft

This paper presents the initial work toward firstprinciples noise prediction for maneuvering rotors. Both the aeromechanical and acoustics aspects of the maneuver noise problem are discussed. The comprehensive analysis code, CAMRAD 2, was utilized to predict the time-dependent aircraft position and attitude, along with the rotor blade airloads and motion. The major focus of this effort was the ...

Rotorcraft Vibration and Noise Prediction Using a Unified Aeroelastic Analysis

A study of the combined helicopter noise and vibration problem was conducted. A refined aerodynamic model capable of calculating the unsteady surface pressure distribution on rotor blade/flap combinations is developed and coupled with an aeroelastic analysis simulation code. An acoustic prediction tool based on WOPWOP is combined with the aeroelastic analysis based on a flexible blade with coup...

Local Search for Designing Noise-Minimal Rotorcraft Approach Trajectories

NASA and the international community are investing in the development of a commercial transportation infrastructure that includes the increased use of rotorcraft, specifically helicopters and civil tilt rotors. However, there is significant concern over the impact of noise on the communities surrounding the transportation facilities. One way to address the rotorcraft noise problem is by exploit...