1,721,123 research outputs found
Design of solar high altitude long endurance aircraft for multi payload & operations
No full textResearch is being carried out at the Turin Polytechnic University with the aim of designing a HAVE/UAV (High Altitude Very-long Endurance/ Unmanned Air Vehicle). The vehicle should be able to climb to an altitude of 17-20 km by taking advantage of direct sun radiation and maintaining a level flight; during the night, a fuel cells energy storage system would be used. A computer program has been developed to carry out a parametric study for the platform design. The solar radiation change over one year, altitude, masses and efficiencies of the solar and fuel cells, as well as the aerodynamic performances have all been taken into account. The parametric studies have shown how the efficiency of the fuel and solar cells and mass have the most influence on the platform dimensions. High modulus CFRP has been used in designing the structure in order to minimize the airframe weight. A Blended Wing Body (BWB) configuration of Solar HALE Aircraft Multi Payload & Operation (SHAMPO) with 8 brushless electric motors has been developed, as a result of the parametric study. The BWB solution, compared with conventional designs, seems to provide the best compromise between performance, availability of surfaces for solar-cells, and volume for multi-payload purposes. Several profiles and wing plans have been analyzed using the CFD software Xfoil and Vsaero. The airfoil coordinates at the root and along the wing span as well as the wing planform were optimised to achieve the best efficiency. A FEM analysis was carried out using the Msc/Patran/Nastran code to predict the static and dynamic behaviour of the UAV structure. © 2006 Elsevier SAS. All rights reserve
Design, manufacturing and testing of a HALE-UAV structural demonstrator
No full textSome main activities have been developed as part of the HELINET research project which was financed in January 2000, by the European Commission, (Fifth Framework Program in the IST action), to develop a European project in the field of stratospheric platforms. From the aeronautical point of view the following items were studied: (1) the design of an autonomous high altitude long-endurance unmanned air vehicle (HALE-UAV) platform capable of remaining aloft for very long periods of time (between 6 and 9 months) using a solar-powered and fuel cell system and to gain a complete understanding of the feasibility of a near-term aerodynamic HALE concept, in particular as far as stratospheric platforms are concerned (mainly dependent on high efficiency and reliability of solar cells, fuel cells and electric motors), (2) an evaluation of the production and service costs and an assessment of the safety and regulatory aspects of the platform, and (3) the manufacturing of a scale-sized technological demonstrator and the execution of static tests on it up to the ultimate load. The first HELIPLAT (HELIos PLATform) configuration was worked out, on the basis of a preliminary parametric study. The platform was a twin-boom tail type monoplane with eight brushless motors, a long horizontal stabilizer and two rudders. A scaled-prototype was designed to demonstrate the feasibility of this configuration and to perform some structural static and dynamic tests on it. The main CFRP structures were manufactured by CASA (Spain): the principal wing and horizontal tail tubular spars, booms, vertical tail spars and some reinforced ribs. These parts were delivered to the Aerospace Engineering Dept. (DIASP) at the Politecnico di Torino (POLITO) and assembled using special joints while some other necessary parts were manufactured by POLITO-DIASP. A parallel activity was performed to define the structural test configurations and structural test frame. The manufacturing activities and the development of the structural test system is described in the first part of the paper. Static and dynamic experimental tests were performed in two phases (2003 and 2004) on the prototype and the results of the static tests are presented in this paper and compared with numerical and theoretical computations. 2007 Elsevier Ltd. All rights reserved
Structural Analysys of Slender Composite Thin-Walled Box-Beam for Aeroelastic Applications
No full textImpact of Control Surface Stiffness on Aeroelastic Divergence and Reversal
No full textThis study addressed a gap in traditional aeroelastic models by incorporating the finite torsional stiffness of control surfaces within an extended two-degree-of-freedom analytical framework. By deriving the governing equations and evaluating the static aeroelastic phenomena of Divergence and Control Surface Reversal, the
study demonstrated the significance of including control surface hinge stiffness, which has been typically neglected or oversimplified in existing literature. The results show that ignoring the finite stiffness of the control surface can lead to nonconservative estimations, notably overestimating control surface effectiveness and the associated reversal speed.
The analytical outcomes revealed that a decrease in control surface torsional stiffness relative to the main aerodynamic surface accelerates the onset of Control Surface Reversal. This finding
underscores the importance of precise stiffness characterization in the design phase, especially for critical aeroelastic assessment
COSTRUZIONI AERONAUTICHE: Eserciziario minimo con soluzioni
No full textIl volume è una raccolta di esercizi e di temi d'esame assegnati nei corsi di Costruzioni Aeronautiche e Tecnica delle Costruzioni Aeronautiche del Politecnico di Torino. Ogni esercizio affrontato è brevemente introdotto e quindi risolto introducendo in dettaglio non solo i calcoli, ma anche la spiegazione dei passi necessari per il raggiungimento del risultato. Lo scopo principale è quello di dare un supporto agli studenti che devono sostenere l'esame fornendo loro le nozioni fondamentali per il calcolo della risposta statica delle strutture aeronautiche e del calcolo dello stato tensionale dei componenti lo schema di guscio rinforzato o semiguscio ideale in accordo con l'approccio della "trave a semiguscio". Tali nozioni costituiscono la base per gli approcci avanzati di analisi strutturale forniti nei successivi corsi specialistici. Vengono poi introdotti altri aspetti importanti nelle costruzioni aeronautiche quali la fatica, l'instabilità di pannelli irrigiditi e il dimensionamento di piastre di attacco. Per la parte teorica si fa riferimento a quanto riportato negli appunti delle lezioni
"Airfoil Geometry of Optimal Propeller for the Rapid 200-FC"
No full textDeliverable D8/2 App.2, ENFICA-F
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