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To reduce the cost of small wind turbines, a prototype of a butterfly wind turbine (6.92 m in diameter), a small vertical-axis type, was developed with many parts made of extruded aluminum suitable for mass production. An overspeed control system with movable arms that operated using centrifugal and aerodynamic forces was installed for further cost reduction. Introducing this mechanism eliminates the need for large active brakes and expands the operating wind speed range of the wind turbine. However, although the mechanism involving the use of only bearings is simple, the violent movement of the movable arms can be a challenge. To address this in the present study, dampers were introduced on the movable arm rotation axes to improve the movement of the movable arms. To predict the behavior of a movable arm and the performance of the wind turbine with the mechanism, a simulation method was developed based on the blade element momentum theory and the equation of motion of the movable arm system. A comparison of experiments and predictions with and without dampers demonstrated qualitative agreement. In the case with dampers, measurements confirmed the predicted increase in the rotor rotational speed when the shorter ailerons installed perpendicularly to the movable arms were used to achieve the inclination. Field experiments of the generated power at a wind speed of 6 m/s (10 min average) showed relative performance improvements of 11.4% by installing dampers, 91.3% by shortening the aileron length, and 57.6% by changing the control target data. The movable arm system with dampers is expected to be a useful device for vertical-axis wind turbines that are difficult to control. [ABSTRACT FROM AUTHOR]

With the gradual maturity and application of digital assembly technology，the interchangeability design adapting to digital quantity transfer is of significant practical significance for improving the efficiency of aircraft control surface design，stabilizing assembly quality and reducing maintenance cost. Taking the interchangeability design of a certain type of aircraft control surface as the research object，the design points are analyzed according to the requirements of the control surface interchangeability，and the interchangeability design process coordinated with digital assembly is established. The structural elements of the interchangeability design are analyzed from the configuration characteristics of the control surface. The technical approach to realize the interchangeability of the control surface is proposed，and the corresponding reference indexes are given. Combined with the test method of aircraft interchangeability，the aileron of a certain type of aircraft is taken as an example to analyse and design the interchangeability of the control surface，which is verified by the actual assembly inspection. The results show that the design process of control surface interchangeability is feasible，which can satisfy the interchangeability requirements

To reduce the cost of small wind turbines, a prototype of a butterfly wind turbine (6.92 m in diameter), a small vertical-axis type, was developed with many parts made of extruded aluminum suitable for mass production. An overspeed control system with movable arms that operated using centrifugal and aerodynamic forces was installed for further cost reduction. Introducing this mechanism eliminates the need for large active brakes and expands the operating wind speed range of the wind turbine. However, although the mechanism involving the use of only bearings is simple, the violent movement of the movable arms can be a challenge. To address this in the present study, dampers were introduced on the movable arm rotation axes to improve the movement of the movable arms. To predict the behavior of a movable arm and the performance of the wind turbine with the mechanism, a simulation method was developed based on the blade element momentum theory and the equation of motion of the movable arm system. A comparison of experiments and predictions with and without dampers demonstrated qualitative agreement. In the case with dampers, measurements confirmed the predicted increase in the rotor rotational speed when the shorter ailerons installed perpendicularly to the movable arms were used to achieve the inclination. Field experiments of the generated power at a wind speed of 6 m/s (10 min average) showed relative performance improvements of 11.4% by installing dampers, 91.3% by shortening the aileron length, and 57.6% by changing the control target data. The movable arm system with dampers is expected to be a useful device for vertical-axis wind turbines that are difficult to control.

Aileron stiffness simulator is a device to simulate the support stiffness of aileron actuator,which is a key device in airplane ground test. The research on the stiffness simulator is beneficial to its design and application,and has important engineering value. In this research,in order to establish the mechanical model accurately,the stiffness reduction factor is proposed. And the correctness of the mechanical model and simulation is verified through the stiffness test. Lastly,the thickness of the simulator is optimized based on the sensitivity of the target stiffness with distance. The results show that the stiffness reduction factor can be used to quickly predict the stiffness,and 7 mm is the optimal stiffness plate thickness of the simulator.

Whirl flutter of a tiltrotor aircraft is a complex aeroelastic phenomenon and it can result in catastrophic consequences. The deflection of an aileron mounted on a wing has the potential to solve this fatal problem. Whirl flutter suppression using an actively controlled aileron is studied in this study. Firstly, a semi-span aeroelastic model is established for the whirl flutter problem using the Hamilton principle. This model is composed of three parts: a rigid rotor, a rigid nacelle and a flexible wing, and the effect of the aileron deflection on the aeroelastic responses is also taken into consideration through a quasi-steady aerodynamic model. In addition, the accuracy of this aeroelastic model is validated with the results of two different wind-tunnel tests. Then, an LQR controller is developed to control the dynamic deflection of the aileron, and a full-dimensional state observer is built to estimate the state of the time-invariant system of a tiltrotor aircraft. Finally, simulations are carried out using the aeroelastic model and the LQR controller at different flight conditions to study the influence of the aileron deflection on whirl flutter. The simulation results demonstrate that the flutter boundary speed can be improved by 18.1% with the active deflection of the aileron, compared with the uncontrolled condition. [ABSTRACT FROM AUTHOR]

In aircraft wings, aileron mass parameter presents a tremendous effect on the velocity and frequency of the flutter problem. For that purpose, we present the optimization of a composite design wing with an aileron, using machine-learning approach. Mass properties and its distribution have a great influence on the multi-variate optimization procedure, based on speed and frequency of flutter. First, flutter speed was obtained to estimate aileron impact. Additionally mass-equilibrated and other features were investigated. It can deduced that changing the position and mass properties of the aileron are tangible following the speed and frequency of the wing flutter. Based on the proposed optimization method, the best position of the aileron is determined for the composite wing to postpone flutter instability and decrease the existed stress. The represented coupled aero-structural model is emerged from subsonic aerodynamics model, which has been developed using the panel method in multidimensional space. The structural modeling has been conducted by finite element method, using the p-k method. The fluid –structure equations are solved and the results are extracted. [ABSTRACT FROM AUTHOR]

For the purpose of improving the performance of the Savonius wind turbine, we added ailerons to the turbine to rotate with the turbine buckets. Ailerons with a relatively simple structure were installed within the rotating area of the Savonius wind turbine. As such, the ailerons did not increase the wind-receiving portion of the wind turbine. A semi-circular shape similar to the bucket was chosen as the aileron. Three sizes of ailerons were used, the largest of which was half the size of the wind turbine bucket. Experiments were conducted using wind tunnel test equipment, where the Savonius wind turbines fitted with ailerons were tested under various installation conditions. In the experiment, the torque generated by the wind turbine was measured at different tip speed ratios. Due to the installation of ailerons, the torque generated by the Savonius wind turbine increased mainly at low tip speed ratios. The torque increased the most when the largest aileron of the three types was used. It was also found that it is possible to improve the efficiency of the wind turbine when using large ailerons. From these results, it can be said that the installation of ailerons is effective for improving the performance of the Savonius wind turbine.

Whirl flutter of a tiltrotor aircraft is a complex aeroelastic phenomenon and it can result in catastrophic consequences. The deflection of an aileron mounted on a wing has the potential to solve this fatal problem. Whirl flutter suppression using an actively controlled aileron is studied in this study. Firstly, a semi-span aeroelastic model is established for the whirl flutter problem using the Hamilton principle. This model is composed of three parts: a rigid rotor, a rigid nacelle and a flexible wing, and the effect of the aileron deflection on the aeroelastic responses is also taken into consideration through a quasi-steady aerodynamic model. In addition, the accuracy of this aeroelastic model is validated with the results of two different wind-tunnel tests. Then, an LQR controller is developed to control the dynamic deflection of the aileron, and a full-dimensional state observer is built to estimate the state of the time-invariant system of a tiltrotor aircraft. Finally, simulations are carried out using the aeroelastic model and the LQR controller at different flight conditions to study the influence of the aileron deflection on whirl flutter. The simulation results demonstrate that the flutter boundary speed can be improved by 18.1% with the active deflection of the aileron, compared with the uncontrolled condition.

Most modern aircraft employ discrete ailerons for roll control. The induced drag, rolling moment, and yawing moment for an aircraft depend in part on the location and size of the ailerons. In the present study, lifting-line theory is used to formulate theoretical relationships between aileron design and the resulting forces and moments. The theory predicts that the optimum aileron geometry is independent of prescribed lift and rolling moment. A numerical potential flow algorithm is used to evaluate the optimum size and location of ailerons for a wide range of planforms with varying aspect ratio and taper ratio. Results show that the optimum aileron design to minimise induced drag always extends to the wing tip. Impacts to induced drag and yawing moment are also considered, and results can be used to inform initial design and placement of ailerons on future aircraft. Results of this optimisation study are also compared to theoretical optimum results that could be obtained from morphing-wing technology. Results of this comparison can be used to evaluate the potential benefits of using morphing-wing technology rather than traditional discrete ailerons. [ABSTRACT FROM AUTHOR]

Commercial aircraft have well-designed and optimized systems, the result of a huge experience in the field, due to the large fleet of aircraft in operation. For light, utility, or sports aircraft, with a multitude of shapes, tasks, and construction types, there are different solutions that seek to best meet the requirements of the designed aircraft. In this sense, for a sport plane, an increased maneuverability is desired, and the system that controls flaps and wing must be properly designed. A new flap mechanism command solution is proposed and justified in the paper, for use in sports and recreational aviation, in order to achieve angles of braking greater than 40°, take-off and landing in a shorter time and over a shorter distance, as well as the gliding of the aircraft in critical flight conditions or when fuel economy is needed. A finite element model is used to verify the optimized command system for the flap and wing and to check if the strength structure of the aircraft is properly designed. The main result consists of the new design command system for flaps and wings and in verifying, by calculation, the acceptability of the new mechanism proposed from the point of view of the strength of the materials.

Some bird species fly inverted, or whiffle, to lose altitude. Inverted flight twists the primary flight feathers, creating gaps along the wing's trailing edge and decreasing lift. It is speculated that feather rotation-inspired gaps could be used as control surfaces on uncrewed aerial vehicles (UAVs). When implemented on one semi-span of a UAV wing, the gaps produce roll due to the asymmetric lift distribution. However, the understanding of the fluid mechanics and actuation requirements of this novel gapped wing were rudimentary. Here, we use a commercial computational fluid dynamics solver to model a gapped wing, compare its analytically estimated work requirements to an aileron, and identify the impacts of key aerodynamic mechanisms. An experimental validation shows that the results agree well with previous findings. We also find that the gaps re-energize the boundary layer over the suction side of the trailing edge, delaying stall of the gapped wing. Further, the gaps produce vortices distributed along the wingspan. This vortex behavior creates a beneficial lift distribution that produces comparable roll and less yaw than the aileron. The gap vortices also inform the change in the control surface's roll effectiveness across angle of attack. Finally, the flow within a gap recirculates and creates negative pressure coefficients on the majority of the gap face. The result is a suction force on the gap face that increases with angle of attack and requires work to hold the gaps open. Overall, the gapped wing requires higher actuation work than the aileron at low rolling moment coefficients. However, above rolling moment coefficients of 0.0182, the gapped wing requires less work and ultimately produces a higher maximum rolling moment coefficient. Despite the variable control effectiveness, the data suggest that the gapped wing could be a useful roll control surface for energy-constrained UAVs at high lift coefficients., (Creative Commons Attribution license.)

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Abstract: Imaging of a major collision zone between the Tanami region and Aileron Province of the Arunta Orogen in Northern Australia, and recognition that several of the major gold deposits within the Tanami region are within near-surface antiformal stacks or uplifted and exhumed crustal sections associated with major crustal-penetrating shear zones, are fundamental results from the 2005 Tanami Seismic Collaborative Research Project. The suture, which is interpreted to have resulted from collision, separates the northwest-dipping structural grain of the Aileron Province crust in the south from the southeast-dipping structural grain of the Tanami crust in the northwest. The collision between the Tanami region and the Aileron Province is interpreted to have occurred prior to ca. 1840 Ma. The correlation between the surface extension of crustal-penetrating shear zones that extend to the Moho boundary and the locations of known gold-rich mineral fields is significant and has implications for minerals explorers within the Tanami region, and elsewhere. In the near-surface, where the crustal-penetrating structures cut relatively shallow upper crustal Tanami Group rocks, there is a significant increase in the degree of local deformation and results in through-going thrust faults, associated pop-up structures, ramp anticlines and antiformal stacking. All known ore deposits appear to be located within these more complexly deformed zones and therefore have a direct association with larger-scale structures. [Copyright &y& Elsevier]

Abstract: The current full depth aluminium aileron installed on the P180 AVANTI aircraft has been selected, as reference baseline, for the design of a new CFRP aileron developed within the VITAS project (Vector for Innovative Sustainable Air Transportation). This new composite laminate structure, manufactured by using the RTM process, has been designed maintaining the same geometry, functional performances and attachment fittings of the aluminium component. An iterative design methodology, developed by using both simplified and detailed design approach, has led to an optimized aileron concept characterised by a strong reduction of the number of the structural subparts and by a considerable increase of the weight/costs ratio. Finally, the effectiveness of the developed full scale demonstrator has been successfully proved at the ultimate static load, satisfying the same test performed for the certification of the aluminium aileron. [Copyright &y& Elsevier]

The paper is concerned with mechanical phenomena accompanying ground run of aircraft with near-critical slip angles. Such phenomena (reduced effectiveness of directional control, self-excited frictional vibrations of a landing gear, internal resonance of an aileron, transverse oscillations of the legs of a multileg landing gear) are due to the nonlinear dependence of the side force on the slip angles [ABSTRACT FROM AUTHOR]

Abstract: The paper presents the configuration requirements and the strategy of mesh generation for wing-body configurations including spoilers and ailerons. Samples of final mesh features are shown, convergence issues are addressed and a number of sample solutions are discussed with respect to varying incidences, spoiler and aileron deflections and Reynolds numbers. The effects are discussed and compared with measurements. [Copyright &y& Elsevier]

Some bird species exhibit a flight behavior known as whiffling, in which the bird flies upside-down during landing, predator evasion, or courtship displays. Flying inverted causes the flight feathers to twist, creating gaps in the wing's trailing edge. It has been suggested that these gaps decrease lift at a potentially lower energy cost, enabling the bird to maneuver and rapidly descend. Thus, avian whiffling has parallels to an uncrewed aerial vehicle (UAV) using spoilers for rapid descent and ailerons for roll control. However, while whiffling has been previously described in the biological literature, it has yet to directly inspire aerodynamic design. In the current research, we investigated if gaps in a wing's trailing edge, similar to those caused by feather rotation during whiffling, could provide an effective mechanism for UAV control, particularly rapid descent and banking. To address this question, we performed a wind tunnel test of 3D printed wings with a varying amount of trailing edge gaps and compared the lift and rolling moment coefficients generated by the gapped wings to a traditional spoiler and aileron. Next, we used an analytical analysis to estimate the force and work required to actuate gaps, spoiler, and aileron. Our results showed that gapped wings did not reduce lift as much as a spoiler and required more work. However, we found that at high angles of attack, the gapped wings produced rolling moment coefficients equivalent to upwards aileron deflections of up to 32.7° while requiring substantially less actuation force and work. Thus, while the gapped wings did not provide a noticeable benefit over spoilers for rapid descent, a whiffling-inspired control surface could provide an effective alternative to ailerons for roll control. These findings suggest a novel control mechanism that may be advantageous for small fixed-wing UAVs, particularly energy-constrained aircraft., (© 2022 IOP Publishing Ltd.)

Commercial aircraft have well-designed and optimized systems, the result of a huge experience in the field, due to the large fleet of aircraft in operation. For light, utility, or sports aircraft, with a multitude of shapes, tasks, and construction types, there are different solutions that seek to best meet the requirements of the designed aircraft. In this sense, for a sport plane, an increased maneuverability is desired, and the system that controls flaps and wing must be properly designed. A new flap mechanism command solution is proposed and justified in the paper, for use in sports and recreational aviation, in order to achieve angles of braking greater than 40°, take-off and landing in a shorter time and over a shorter distance, as well as the gliding of the aircraft in critical flight conditions or when fuel economy is needed. A finite element model is used to verify the optimized command system for the flap and wing and to check if the strength structure of the aircraft is properly designed. The main result consists of the new design command system for flaps and wings and in verifying, by calculation, the acceptability of the new mechanism proposed from the point of view of the strength of the materials. [ABSTRACT FROM AUTHOR]