New w wing shape for airmodels
03 Aug 2021-Vol. 64, Iss: 2
TL;DR: In this paper, the authors proposed a wing shape that approximates the front seen parabola ideal wing by streight lines: line 1 touches parabolas at the axis origin and is 25 % of the length of the wing, line 2 is tangent of parablas at the wingtip and cuts the hotizontal line at 50 % of "a", and line 3 is tangant to parabla, cuts horizontal line at 25 % "a" and cuts line 2 at 75 % of ''a'' and 50 % ''h''.
Abstract: The new W wing shape (half wing, with “a”half wingspan and “h” wingtip height) approximates the front seen parabola ideal wing by streight lines: line 1 touches parabola at the axis origin and is 25 % of “a”, line 2 is tangent of parabola at the wingtip and cuts the hotizontal line at 50 % of “a”, and line 3 is tangent to parabola, cuts horizontal line at 25 % of “a” and cuts line 2 at 75 % of “a” and 50 % of “h”. Real W wing approximated very close the ideal parabolic wing. The new W wing gives more lateral and directional stability.
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TL;DR: In this article, the aerodynamic design and analysis of winglets is presented from an aerodynamic point of view, where the winglets are small fences placed upward at the tip of the wing to improve the wing efficiency by decreasing the induced drag for a given lift.
Abstract: The design and analysis of winglets is presented from an aerodynamic point of view. The winglets considered are small fences placed upward at the tip of the wing to improve the wing efficiency by decreasing the induced drag for a given lift. Viscous corrections are accounted for by using a two-dimensional viscous polar, with the assumption that at design conditions the flow is fully attached. The comparison of the inviscid and viscous designs indicates that viscosity has little effect on the optimum geometry. In the presence of viscous drag, the winglets produce a small thrust; due to viscosity, the overall efficiency gain is decreased. The effect of a small yaw angle on a wing equipped with such optimal winglets indicates that, even in the presence of viscous effects, they provide weathercock stability.
25 citations
TL;DR: This paper accounts for the competition rules by including those requirements in different ways and with different levels of modelisation, which results in the design of the classic configuration with a lifting tail at take-off, which, with the double-element airfoil, have been features of the UC Davis entries for the last few years.
Abstract: Design is an open ended process driven by the mission requirements. In this paper, we account for the competition rules by including those requirements in different ways and with different levels of modelisation. The first step is achieved with a 'cookie cutter' approach in the rapid prototyping code. This is followed by a more accurate estimation of the take-off velocity with total airplane weight, which will be matched with the longitudinal equilibrium capabilities of the complete aircraft. In this process, the location of the centre of gravity is found. The maximum payload is also obtained. With engine-off, the glider can be trimmed for maximum distance or maximum duration. Winglet design is also discussed. Finally, the design of the classic configuration with a lifting tail at take-off is explained, which, with the double-element airfoil, have been features of the UC Davis entries for the last few years.
3 citations
01 Jan 2019
TL;DR: In this article, different types of wings are computed by low and high-fidelity methods to compare their aerodynamic characteristics and the goal of optimization is minimization of aerodynamic drag.
Abstract: In this article different wings are computed by low and high-fidelity methods to compare their aerodynamic characteristics. Thanks to the unusual properties of the wing with the bell-shaped lift distribution, several general geometrical variants of the wings were calculated and their results are presented in this work. Three general wings are assumed and their geometry is defined as rectangular, trapezoidal and elliptical. Airspeed, total lift force, shape of airfoil and root chord are defined, and bending moment is assumed as a surrogate model for wing weight. The goal of optimization is minimization of aerodynamic drag.
3 citations
TL;DR: In this article, an explanation for the lift of an airfoil is proposed based on an intuitive use of Newton's law and the application of the well-established inviscid flow theory of thin airfoils.
Abstract: In this note, an attempt at giving as simple as possible an explanation for the lift of an airfoil is proposed based on an intuitive use of Newton's law on one hand and the application of the well-established inviscid flow theory of thin airfoils on the other. A thin parabolic cambered plate is chosen as profile at zero incidence because the flow it produces minimises viscous effects and the particle paths along the plate, above and below it, have the same length, thus proving the 'equal transit' explanation to be wrong.
2 citations