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Structural design of a ULM PrandtlPlane wing system

The task of the thesis is to optimize the wing structure of a non conventional very light airplane starting from a PrandtlPlane prototype currently in phase of development.
This treatment is divided in several parts. In the first part an introduction about the main features of a PrandtlPlane aircraft is given.
In particular, the first chapter explains what was the idea which led to this new solution, its main advantages and the reasons which led to employ this configuration in the branch of light aviation.
The second part depicts all the features of the prototype, in terms of regulation, structures, materials used to build it, and loads that act on the structure. The third part aims to the describe the design process and how it is implemented, starting from a previous tool and showing how this process can be used in order to further develop this configuration.
Finally, in the last part of this job the results of the design process will be verified through a finite element analysis, in order to perform a comparison between the prototype and the optimized structure.

Mostra/Nascondi contenuto.
Chapter1 Introduction In the last years,the increasing cost of fuel and the need for a reduction in air traffic pollution has led civil aviation to move its attention toward the construction of more efficient aircraft. In order to achieve this goal, the aeronautic industries have usually tried to improve aerodynamics and to build lighter structures but, recently several solutions have been proposed in order to lead a radical change in the standard aircraft configuration. Among them, the attention of the aeronautic community has been focused on the Blended Wing Body and the multiplane configurations and currently, NASA and Boeing are developing the first one. This thesis aims to examine one of the multiplane configuration, which is called PrandtlPlane . In particular the present work faces the problem of finding the minimum weight solution for the main wing structures of a n ultralight PrandtlPlane . In the last years, Pisa University Aerospace Engineering department has started this project following the idea of Best wing System, an alternative aircraft configuration elaborated by L.Prandtl in 1924. 1.1 Best Wing System The Best Wing System idea was presented by L.Prandtl in the TN 182 NACA report, in which Prandtl showed that once wingspan and total lift are given, as the number of wings used increases, the induced drag decreases. Then, for instance a biplane is more efficient than a monoplane, triplane is more efficient than biplane and so on. In this respect the best result available is a box-shaped wing, shown in Figure 1.1, then called Best Wing System. The main characteristics of this configuration, as shown in [1], are an equal lift on upper and lower wing and a butterfly shaped (lateral) forces with nil resultant on the vertical winglets (Figure 1.2). Even though such conditions are necessary to minimize the induced drag, they aren’t suitable for practical use, since 1

Laurea liv.II (specialistica)

Facoltà: Ingegneria

Autore: Alberto Viti Contatta »

Composta da 160 pagine.

 

Questa tesi ha raggiunto 273 click dal 07/07/2011.

 

Consultata integralmente una volta.

Disponibile in PDF, la consultazione è esclusivamente in formato digitale.