Assessment of airfoil aerodynamic characteristics is essential part of any optimal airfoil design procedure. This paper illustrates rapid and efficient method for determination of aerodynamic characteristics of an airfoil, which is based on viscous-inviscid interaction. Inviscid flow is solved by conformal mapping, while viscous effects are determined by solving integral boundary layer equations. Displacement thickness is iteratively added to the airfoil contour by alternating inviscid and viscous solutions. With this approach efficient method is developed for airfoil design by shape perturbations. The procedure is implemented in computer code, and calculation results are compared with results of XFOIL calculations and with experiment. Eppler E387 low Reynolds number airfoil and soft stall S8036 airfoil are used for verification of developed procedure for Reynolds numbers 200000, 350000, and 500000. Calculated drag polars are presented in this paper and good agreement with experiment is achieved as long as small separation is maintained. Calculated positions of laminar separation, reattachment, and turbulent separation closely follow experimental measurement. The calculations are performed in relatively short time, which makes this approach suitable for low Reynolds number airfoil design.

Usually fin represent as one of the important structures in all type of airplane and the fin structure was greatly improved, especially for modern supersonic speed constructions. The main aim of delta fin construction is to minimize the weight of structure as much as possible and keeping the stiffness of material structural in margin of safety under design load [1]. The primary difference between classical method and finite element are the view structure and the ensuring solution procedure. Classical method considers the structure as a continuum whose behavior is governed by partial or ordinary differential equations [2]. By using finite element method consider the structure to be an assembly of small finite-sized particles. The behavior of the particles and the overall structure is obtained by formulating a system of algebraic equation that can be readily solved by developed methodology, which will be presented in form of software.

Abstract –Wings are the main lift generating sources for any aerospace vehicle. The performance of an airborne vehicle largely depends on its wing design. That is why it is important to understand and be able to calculate wing characteristics in every design process. The analysis of the 3 dimensional transonic flow over ONERA M6 wing at two Mach numbers and angles of attack from 0 to 6 degrees and operating Reynolds number of 11x106 is presented. Computational Fluid Dynamics CFD as a widely used analysis and design tool still need to be validated by comparison with experiment. Ansys/Fluent is used to solve the governing equations with k-SST turbulence model. The validation is done through comparing pressure coefficient distributions over wing surfaces at seven span locations, with experimental measurement . Wing geometry is successfully modeled inside Ansys geometry modeler and unstructured mesh is generated with Ansys mesh modler. Results show good agreement with experimental data at Mach number of 0.84 and 3 degrees angle of attack. On the other hand, as Mach number and angle of attack are increased, numerical results show poor accuracy in capturing shock wave position. 

The characteristics of composite materials are of high importance to engineering applications; therefore the increasing use as a substitute for conventional materials, especially in the field of aircraft and space industries. It is a known fact that researchers use finite element programs for the design and analysis of composite structures, use of symmetrical conditions especially in complicated structures, in the modeling and analysis phase of the design, to reduce processing time, memory size required, and simplifying complicated calculations, as well as considering the response of composite structures to different loading conditions to be identical to that of metallic structures. Finite element methods are a popular method used to analyze composite laminate structures. The design of laminated composite structures includes phases that do not exist in the design of traditional metallic structures, for instance, the choice of possible material combinations is huge and the mechanical properties of a composite structure, which are anisotropic by nature, are created in the design phase with the choice of the appropriate fiber orientations and stacking sequence. The use of finite element programs (conventional analysis usually applied in the case of orthotropic materials) to analysis composite structures especially those manufactured using angle ply laminate techniques or a combination of cross and angle ply techniques, as well considering the loading response of the composite structure to be identical to that of structures made of traditional materials, has made the use of, and the results obtained by using such analysis techniques and conditions questionable. Hence, the main objective of this paper is to highlight and present the results obtained when analyzing and modeling symmetrical conditions as applied to commercial materials and that applied to composite laminates. A comparison case study is carried out using cross-ply and angle-ply laminates which concluded that, if the composition of laminate structure is pure cross-ply, the FEA is well suited for predicting the mechanical response of composite structure using principle of symmetry condition. On the other hand that is not the case for angle-ply or mixed-ply laminate structure.

Modeling of take-off and landing motion for a fixed wing (UAV) is necessary for developing an automatic take off and landing control system (ATOL). Automatic take off and landing system becomes an important system due to wide spread of unmanned aerial vehicles in different applications ranging from intelligence, surveillance, up to missile firing. Automatic take off and landing system reduces damage to an unmanned aerial vehicle and its payload that may be caused by human pilot errors. Furthermore, training human pilot to a sufficient level of skill and experience for takeoff and landing may take several years and significant cost. A human pilot also may impose additional restrictions for UAV operation especially at night time or dusty desert conditions. Although, ATOL adds complexity to the system, it reduces the long run cost and risk caused by takeoff and landing process, and makes UAV takeoff from different runways and at different atmospheric conditions. A mathematical model for takeoff is successfully developed for a small fixed wing UAV. A Matlab/Simulink simulation model is prepared for the ground roll phase, and some simulation results are also shown.