this work deals with effects of asymmetric stiffness on the dynamic behaviour of the rotor system. the analysis is presented through an extended lagrangian hamiltonian mechanics on the asymmetric rotor system, where symmetries are broken in terms of the rotor stiffness. the complete dynamics of asymmetries of rotor system is investigated with a case study. in this work, a mathematical model is ...

Small unmanned aerial vehicles (SUAV) are beginning to dominate the area of intelligence, surveillance, target acquisition and reconnaissance (ISTAR) in forward operating battlefield scenarios. Of particular interest are vertical take-off and landing (VTOL) variants. Within this category co-axial rotor designs have been adopted due to their inherent advantages of size and power to weight ratio....

This paper presents the performance analysis and a parametric study of equivalent ducted/un-ducted rotors using high-fidelity CFD methods. A model-scale ducted rotor case by NASA was analysed used as initial design. An un-ducted producing same thrust power first derived momentum theory. The configurations were later scaled to support four-rotor vehicle 6,000 kg BEMT model. High-fidelity simulat...

The goal of the European project muFly is to build a fully autonomous micro helicopter, which is comparable to a small bird in size and mass. The rigorous size and mass constraints infer various problems related to energy efficiency, flight stability and overall system design. In this research, aerodynamics and flight dynamics are investigated experimentally to gather information for the design...

Hydrodynamic performance of gas microbearings, fabricated with deep X-ray lithography and electroplating, will be presented in this article. Static performance in terms of load parameters and attitude angles was calculated using Molecular Gas Lubrication (MGL) theory. Threshold speed and allowable rotor mass were calculated to investigate safe operating conditions of the fabricated gas microbea...

Multiple metrics are applied to the design of a large civil tiItrotor, integrating minimum cost and minimum environmental impact. The design mission is passenger transport with similar range and capacity to a regional jet. Separate aircraft designs are gener ated for minimum empty weight, fuel burn, and environmental impact. A metric specifically developed for the design of aircraft is employed...

An investigation on new rotor blade designs conceived to produce higher exit relative kinetic energy of a mixed flow turbine is undertaken. Accelerating the through in frame reference improves transfer shaft, which only produced rotating rotor. A three-dimensional converging channel might respond analysis requirements subsonic regimes. Effectively, machine experiences 3.71 % and 3.67 increase w...

This paper addresses the design and commutation of a novel kind of spherical stepper motor in which the poles of the stator are electromagnets and the poles of the rotor (rotating ball) are permanent magnets. Due to the fact that points on a sphere can only be arranged with equal spacing in a limited number of cases (corresponding to the Platonic solids), design of spherical stepper motors with...

The main objective of this research is to improve the feasibility of Energy Momentum Wheels for satellite systems through the development of robust LTI and gain-scheduled controllers for high-speed flywheel rotors supported on active magnetic bearings. A hybrid combination between H∞ loop-shaping and μ-synthesis is used in this paper to design controllers. In order to reduce the computational c...