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Article
Publication date: 30 January 2007

Yuan Su, Yihua Cao and Kungang Yuan

This paper aims to present a theoretical method for analyzing the stability and control of a hingeless helicopter in the presence of windshear.

Abstract

Purpose

This paper aims to present a theoretical method for analyzing the stability and control of a hingeless helicopter in the presence of windshear.

Design/methodology/approach

In this paper, the stability and control of a hingeless helicopter in the presence of windshear are investigated. First, the rotary wing dynamic model considered is the one of flap‐pitch (including the elastic deformation of the control system)‐torsion coupling. The induced velocity nonuniform distribution derived from vortex theory is taken into account. Then, as for atmospheric turbulence, the linear windshear model is used for modeling the variation of wind field. Finally, according to the calculated results of the stability characteristic roots and the control response of the helicopter, the helicopter performance in wind shear field is analyzed, and some conclusions are obtained.

Findings

Some useful conclusions are obtained through sample analysis.

Research limitations/implications

Although the analyses for stability and control of a hingeless helicopter in the presence of windshear could be obtained using the current method, the model of complex wind field will still be expected in future studies.

Practical implications

A very useful method for analyzing helicopter stability and control.

Originality/value

The proposed method is valid and available for the analysis of helicopter flight dynamics.

Details

Aircraft Engineering and Aerospace Technology, vol. 79 no. 2
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 1 December 2004

Yihua Cao, Yong Chen, Kungang Yuan and Changjiang Jin

Control laws that are based on the nonlinear inverse dynamics (NID) of the aircraft offer the potential for providing improved levels of performance over conventional…

Abstract

Control laws that are based on the nonlinear inverse dynamics (NID) of the aircraft offer the potential for providing improved levels of performance over conventional flight control designs. The NID and its application in the flight control during windshear penetration are introduced here. With the employment of a real engineering windshear model and NID, a low‐altitude windshear penetration flight control law is designed. The simulative calculation results indicated that the NID control logic works effectively in the trajectory control of the aircraft during the penetration of windshear.

Details

Aircraft Engineering and Aerospace Technology, vol. 76 no. 6
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 6 September 2011

Yihua Cao, Kungang Yuan and Guozhi Li

The purpose of this paper is to describe a methodology for predicting the effects of glaze ice geometry on airfoil aerodynamic coefficients by using neural network (NN…

Abstract

Purpose

The purpose of this paper is to describe a methodology for predicting the effects of glaze ice geometry on airfoil aerodynamic coefficients by using neural network (NN) prediction. Effects of icing on angle of attack stall are also discussed.

Design/methodology/approach

The typical glaze ice geometry covers ice horn leading‐edge radius, ice height, and ice horn position on airfoil surface. By using artificial NN technique, several NNs are developed to study the correlations between ice geometry parameters and airfoil aerodynamic coefficients. Effects of ice geometry on airfoil hinge moment coefficient are also obtained to predict the angle of attack stall.

Findings

NN prediction is feasible and effective to study the effects of ice geometry on airfoil performance. The ice horn location and height, which have a more evident and serious effect on airfoil performance than ice horn leading‐edge radius, are inversely proportional to the maximum lift coefficient. Ice accretions on the after‐location of the upper surface of the airfoil leading edges have the most critical effects on the airfoil performance degradation. The catastrophe of hinge moment and unstable hinge moment coefficient can be used to predict the stall effectively.

Practical implications

Since the simulation results of NNs are shown to have high coherence with the tunnel test data, it can be further used to predict coefficients at non‐experimental conditions.

Originality/value

The simulation method by using NNs here can lay the foundation of the further research about the airfoil performance in different ice cloud conditions through predicting the relations between the ice cloud conditions and ice geometry.

Details

Aircraft Engineering and Aerospace Technology, vol. 83 no. 5
Type: Research Article
ISSN: 0002-2667

Keywords

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Article
Publication date: 28 June 2013

Sheau‐yueh J. Chao

The purpose of this paper is to provide the historical background of genealogical records and analyze the value of Chinese genealogical research through the study of names…

Abstract

Purpose

The purpose of this paper is to provide the historical background of genealogical records and analyze the value of Chinese genealogical research through the study of names and genealogical resources.

Design/methodology/approach

The paper examines the historical evolution and value of Chinese genealogical records, with the focus on researching the Islamic Chinese names used by the people living in Guilin. The highlight of this paper includes the analysis and evolution of the Islamic Chinese names commonly adopted by the local people in Guilin. It concludes with the recommendations on emphasizing and making the best use of genealogical records to enhance the research value of Chinese overseas studies.

Findings

The paper covers the history of Islam and describes how the religion was introduced into China, as well as Muslims' ethnicity and identity. It also places focus on the importance of building a research collection in Asian history and Chinese genealogy.

Research limitations/implications

This research study has a strong subject focus on Chinese genealogy, Asian history, and Islamic Chinese surnames. It is a narrow field that few researchers have delved into.

Practical implications

The results of this study will assist students, researchers, and the general public in tracing the origin of their surnames and developing their interest in the social and historical value of Chinese local history and genealogies.

Social implications

The study of Chinese surnames is, by itself, a particular field for researching the social and political implications of contemporary Chinese society during the time the family members lived.

Originality/value

Very little research has been done in the area of Chinese local history and genealogy. The paper would be of value to researchers such as historians, sociologists, ethnologists and archaeologists, as well as students and anyone interested in researching a surname origin, its history and evolution.

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