In this paper the design, fabrication and analysis of behavior by full-scale ver-ification testing for the tail rotor blade of composite laminated materials for a heavy transport helicopter is given. The verification test program for the tail rotor blade encompassed static and dynamic test-ing. The static tests of the blade involved experimental evaluation of torsional and flexional blade stif...

This paper presents the application of a viscous adjoint method to the multipoint design optimization of a rotor blade through blade profiling. The adjoint method requires about twice the computational effort of the flow solution to obtain the complete gradient information at each operating condition, regardless of the number of design parameters. NASA Rotor 67 is redesigned through blade profi...

This paper addresses the feasibility of using trailing edge flaps to reconfigure a helicopter rotor blade following a failure of the pitch link, which makes the blade freefloating in pitch and otherwise uncontrollable. A coupled rotor-fuselage model is developed which allowed for rotor anisotropy. A new, optimization-based, trim procedure is developed to determine the dynamics of the failed bla...

by Junye Wang A computational study is carried out to investigate the noise generated by a ten-bladed rotor ingesting low-Mach-number turbulent flow. Two types of turbulent inflows are considered: homogeneous and isotropic turbulence mimicking gridgenerated turbulence in a previous experiment and a turbulent cylinder wake. A hybrid computational approach combining LES with Lighthill’s aeroacous...

A fuzzy logic system (FLS) is developed for ground based health monitoring of a helicopter rotor blade. Structural damage is modeled as a loss of stiffness at the damaged location that can result from delamination. Composite materials, which are widely used for fabricating rotor blades, are susceptible to such delaminations from barely visible impact damage. The rotor blade is modeled as an ela...

Modern utility-scale wind turbines are typically controlled using yaw, generator torque, and blade pitch actuation (Pao and Johnson, 2011). The yaw motor is used to align the rotor with the wind direction for the purpose of maximizing power capture. Generator torque is controlled during below-rated (region 2) operation to maximize power capture by maintaining the optimal tip speed ratio. In abo...

This paper reviews recent achievements in the application of active-materials actuation to counteract aeroelastic and vibration effects in helicopters and fixed wing aircraft. A brief review of the induced-strain actuation principles and capabilities is done first. Attention is focused on the smart rotor-blade applications. The induced twist, active blade tip, and active blade flap concepts are...

A computational study of helicopter vibration and rotor shaft power reduction is conducted using activelycontrolled trailing-edge flaps (ACFs), implemented in both single and dual flap configurations. Simultaneous vibration reduction and performance enhancement is demonstrated under level flight condition at high advance ratios, where dynamic stall effects are significant. Power reduction is ac...

On the cover: Representation of the flow around a helicopter blade with a Gurney flap. Summary Today's helicopters are the result of collaborative work in mechanical engineering and aeronautics. The European project " Clean Sky " aims at improving the efficiency and the global transport quality of aircraft. In the field of rotorcraft, the research in this project is currently focussing on activ...

The problem of helicopter parameter estimation and blade number selection is addressed. The parameters are estimated based on Maximum Likelihood methods, and the corresponding Cramér-Rao bounds are derived. To avoid ambiguities in blade number estimation, we apply information theoretic criteria for blade number selection incorporating alternate penalty functions. We assume that a clutter filter...