China
Africa
Explore chapters and articles related to this topic
Canard Airplanes and Biplanes
Published in James DeLaurier, Aircraft Design Concepts, 2022
It was most noted for tracking down and disabling the German battleship “Bismarck”, as well as performing notable service in the Mediterranean. In many ways, it looks even more primitive than the Fokker design, having wire bracing as well as struts. In fact, its crews affectionately referred to it as a “Stringbag”. So, the question must be asked as to why such designs persisted in a time when streamlined monoplanes were possible. The answer is that biplanes can offer aerodynamic advantages for situations where the wing-spans are fixed. Consider the following illustration for wings of given span b:
From Radio-Controlled Model Aircraft to Drones
Published in David R. Green, Billy J. Gregory, Alex R. Karachok, Unmanned Aerial Remote Sensing, 2020
David R. Green, Cristina Gómez
Fixed-wing platforms have been subdivided into high-wing monoplanes or biplanes, with both powered and power/powerless categories; the latter better known as ‘gliders’. In practice, fixed-wing small-scale aircraft have tended to find more favour for applications than rotary wing in the past. The reason for this is that monoplanes have good stability and a slow flying capability. Biplanes, however, although more complicated to construct and more susceptible to damage, offer advantages of an increased wing area and therefore an increased capacity to carry equipment and to fly slowly. Seldom mentioned in the literature, gliders have also found uses where there is a need for quiet operation e.g. wildlife monitoring and habitat surveys, but they generally offer less of a practical solution than a powered plane.
Adventures in Aeronautical Design: The Life of Hilda M. Lyon
Published in The International Journal for the History of Engineering & Technology, 2020
On graduation, Hilda joined the Siddeley-Deasy Motor Company in Coventry, one of the smaller aircraft builders, as an aircraft technical assistant undertaking stress analysis calculations and working directly under the Chief Designer. In 1920, Hilda moved to the Bristol firm of George Parnall & Company, another small firm. There she calculated stresses in the bracing wires of a proposed large biplane bomber and worked on several other projects, none of which went into production, until 1924. She later wrote that in her first two jobs she ‘was the Stress Office and the Aerodynamics Department, responsible only to the Chief Designer for my work and with no assistants to check it’ and ‘gradually learned to speak the engineering language’. About this time, Hilda came to see herself as an engineer rather than a mathematician and joined the Women’s Engineering Society. In 1922, she was elected an Associate Fellow (now known as ‘Member’) of the Royal Aeronautical Society.
Structural design and analyses of a fabric-covered wind turbine blade
Published in Advanced Composite Materials, 2019
Dong-Guk Choi, Chan-Ho Kwak, Soo-Yong Lee, Jae-Sung Bae, Hak-Gu Lee
Large WT blades have been studied with an emphasis on decreasing weight and increasing performance. However, thus far, the rate of weight reduction has been very small. Cox and Andreas [4] designed a 10-MW WT blade using hybrid composite structures with glass and carbon composites to keep the weight down. In particular, they used 0° carbon fiber and ±45° glass fiber. Balokas et al. [5] compared the failure characteristics between glass and carbon fiber with respect to large-scale WT blade applications. They concluded that carbon fiber plies provided a lower critical load in comparison to that of E-glass fibers. Roth-Johnson et al. [2] designed the spars of a 100-m biplane WT blade to improve the overall performances of the blade and reduce its weight. They anticipated significant weight reductions in the WT blades because the root bending moment of their biplane spar had a 75% smaller maximum root bending moment than a monoplane spar. Buckney et al. [6] studied the structural efficiencies of a new WT blade design by using topology optimization, in which alternative structural layouts were investigated to minimize the blade’s weight as well as the wind energy costs. Barnes et al. [7] designed WT blade structures using a genetic optimization algorithm. The variables of their optimal design were the chordwise location of the spar, trailing edge reinforcement, and shear web spanwise location. The mass of the blade was reduced by 3.5–7.4%. Ha et al. [8] and Hayat et al. [9] researched the effects of shallow-angled symmetric and asymmetric skins with off-axis fiver angles of less than 45° for a WT blade. Applying the 35° or 25° shallow-angled skin, they reduced the weight of the WT blade by up to 8% and 13%, respectively. Although the usage of carbon composites, shallow-angled skins, optimal design techniques, and biplane spars have led to improvements in WT blades, the structural design concept, such as that depicted in Figure 1, has not fundamentally changed for the past decade. These research efforts have not led to an innovative structural design of large-scale WT blades because these blades still utilize the conventional design concept and are accordingly heavy.
Preliminary design procedure for large wind turbine blades based on the classical lamination theory
Published in Advanced Composite Materials, 2021
In this context, the blade structure significantly affects the blade stiffness of a wind turbine. Thus, it is one of the most important research areas with respect to wind turbines. Balokas and Theotokoglou [12] examined the behavior of a box girder of a blade under flap-wise loading for both GFRP and CFRP materials using the quasi-static finite element analysis (FEA) and a post-processing methodology. By utilizing two types of analyses, such as two-dimensional and three-dimensional finite element models, stress distributions and deflections were obtained. Hayat and Ha [13] conducted a parametric study on typical blade skin laminates to explore potential improvements to the existing composite layup design of large blades. The study was extended to perform a multi-objective optimization, which in turn lead to an optimal design of blade composite layup. Furthermore, all design requirements and all design load conditions were simultaneously considered and evaluated. Perry et al. [14] presented a structural design of the spars for 100-m biplane wind turbine blades. They focused on the design of the internal biplane spar structure for 100-m biplane blades. Several spars were designed to approximate the Sandia SNL100-00 blade (monoplane spar) and biplane blade (biplane spar). Jang and Ahn [15] presented a theory for a two-dimensional linear cross-sectional analysis, recovery relationship, and a one-dimensional nonlinear beam analysis for a composite slender wing structure with an initial twist using VABS. Choi, et al. [16] studied the structural designs of fabric-covered wind turbine blades. The structural properties of the blade sections calculated via VABS were compared with those of the reference model, i.e. the NREL-5 MW wind turbine blade. Barr et al. [17] optimized tow-steered composite wind turbine blades for static aeroelastic performance with multiple materials and angles and enabled the coupled bending–twist deformations under aerodynamic loads. Additionally, an optimization of the spar caps in wind turbine blades were examined by Liao et al. [18]. The thickness and location of the spars were chosen as design variables. An aeroelastic simulator was used along with the unsteady blade element momentum (BEM) code. Based on previous studies, it was determined that an optimal design for the spar cap and numerous repetitive design changes were required for the structural design of a blade.