Stability And Control Of Conventional And Unconventional Aircraft Configurations

Author : Seung-Hyeog Nah
Publisher :
ISBN 13 :
Total Pages : pages
Book Rating : 4.:/5 (16 download)

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Download or read book Desaid written by Seung-Hyeog Nah and published by . This book was released on 1991 with total page pages. Available in PDF, EPUB and Kindle. Book excerpt: As all engineering works are a blend of theory andempiricism, aircraft design, by its nature, represents amixture of aircraft designer s knowledge obtained fromaeronautical engineering disciplines and its usagecombined with his experience. This means not only theapplication but also the integration of all thefundamental knowledge of aerodynamics, structure, propulsion, stability and control, operational andeconomic aspects, etc., based upon the designer sjudgements and experiences. Thus the tasks involved in designing an aircraftconfiguration, without exception, show complexcharacteristics, considering the fact that aircraftconfiguration design means the integration of componentssuch as lifting surfaces (wing), fuselage, power-plant, control surfaces (tail or canard), and undercarriage. The discrepancies and mismatches among the aircraftcomponents make the configuration design iterative, repetitive, and thus time - consuming. Such complexitiesof configuration design processes often requirecompromise, through trial and error, to resolve conflictsbetween the major design areas. Moreover, it takes tens of years to become aexperienced design expert whose sound judgement, basedupon experience and profound knowledge, influencesgreatly the aircraft configuration design. Thedifferences in judgements depend upon the designers imagination and experience, and they are the cause ofvariations in aircraft configurations. Therefore, the efforts were made to overcome thosedifficulties which hinder the aircraft designer frommaking the task of configuration design more efficient, and further to assist the aircraft designer in getting aneasy and interactive preliminary aircraft configurationwithout always relying upon design experts. Hence thecurrent research project is directed at the developmentof an expert system for aircraft design. This involvesthe use of Artificial Intelligence and its programminglanguage called PROLOG (PROgramming in LOGic). The research started from a thorough analysis of themajor component design areas and has constructed anEXPERT SYSTEM to find out the efficient Control Mechanism which can search intensively for the solutions to designproblems for all types of aircraft; civil and military, subsonic and supersonic, conventional and unconventional, etc. In addition, users can have access to theexplanations of important items such as a design process, terminology, equations, and results. The explanationfacility is one of the most important functions ofExpert Systems. Partly due to the limit of computer capacity and partlydue to the magnitude of laborious program execution atthis stage, the system implementation has focused onthe high - subsonic, conventional and jet transportaircraft categories. The approach taken was to find anefficient and effective control mechanism (i. e. anInference Engine), which integrated the PARAMETRICSTUDY, WING DESIGN, FUSELAGE DESIGN, ENGINE DESIGN, TAILDESIGN, UNDERCARRIAGE DESIGN, WEIGHT ANALYSIS AND COSTANALYSIS into a whole configuration system. The comparison between Expert System results andexisting aircraft such as Boeing 747, Airbus 300 series, BAe 146 series, McDonnell Douglas MD series, etc., showedthe permissible ranges of error to be within about 10 %. Such results enable the Expert System to claim that itcan act as a useful design tool for the aircraft designerin the initial stage of aircraft configuration design. Finally, the author believes that the control mechanismdevised for this Expert System can be used as a soundbasis for extending the Expert System to include othertypes of aircraft and further to encompass spacecraftdesign, as the designer wishes.