Aircraft concepts of tomorrow, such as high aspect ratio wing aircraft, are far more integrated between technical disciplines and thus require multi-disciplinary design approaches. Design tools able to predict associated dynamics need to be developed if such wing concepts are to be matured for use on future transport aircraft. The Cranfield University Beam Reduction and Dynamic Scaling (BeaR D S ) Programme provides a framework that scales a conceptual full size aircraft to a cantilevered wing model of wind tunnel dimensions, such that there is similitude between the static and dynamic behaviour of the model and the full size aircraft. This process of aeroelastically scaled testing combines the technical disciplines of aerodynamics, flight mechanics and structural dynamics, to provide a means by which future concept aircraft can be de-risked and explored. Data acquisition from wind tunnel testing can then be used to validate fluid-structure interaction frameworks that model the aeroelastic effect on the flight dynamics of the aircraft. This paper provides an overview of the BeaR D S methodology, and focuses on the Phase I of the programme, being the development of a reduced Cranfield A-13 aircraft cantilevered wing, to mitigate risk associated with the manufacturing and instrumentation approach. It is shown that a low cost acquisition system of commercial Inertial Measurement Units (IMUs) can measure the response of the wing within the desired frequency range. Issues associated with the Phase I testing are discussed, and methods are proposed for the Phase II programme that allow these problems to be resolved for a larger scale flexible wing with active control surfaces.

A feedback control demonstrator is described. The demonstrator is intended for the demonstration of control principles applied to flight control of fixed-wing aircraft and hence is suitable for aeronautical programmes. The demonstrator consists of a two degree-of-freedom wing assembly where the wing is free to pitch in an airflow provided by a simple, benchtop wind tunnel. The second degree-of-freedom is provided by a hinged elevator which is actuated by a servomotor. The wing pitch angle is measured with a potentiometer attached to a pivot shaft, thus allowing feedback control of the elevator pitch to be implemented. The aerodynamics of the wing are modelled, the wind tunnel design is described and computational fluid dynamics analysis presented. An embedded controller that implements a Proportional-Integral-Derivative (PID) controller and a graphical interface have been developed. Some details of these are also given.

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Verification and validation of simulation models are critical steps in engineering. This paper aims at verifying the suitability of reduced order aerodynamic models used in an aeroservoelastic framework designed to analyze the flight dynamics of flexible aircraft, known as the Cranfield Accelerated Aircraft Loads Model. This framework is designed for rapid assessment of aircraft configurations at the conceptual design stage. Therefore, it utilizes or relies on methods that are of relatively low fidelity for high computational speeds, such as modified strip theory coupled with Leishmann-Beddoes unsteady aerodynamic model. Hence, verification against higher order methods is required. Although low fidelity models are widely used for conceptual design and loads assessments, the open literature still lacks a comparison against higher fidelity models. This work focuses on steady-trimmed flight conditions and investigates the effect of aerodynamic wing deformation under such loads on aerodynamic performance. Key limitations of the reduced order models used, namely fuselage and interference effects, are discussed. The reasons for the overall agreement between the two approaches are also outlined.

Aircraft performance can be assessed and improved by considering the key variables linked to weight and aerodynamics in the Breguet range equation. In this paper, the authors present a method for wing design that allows a reduction in induced drag and minimization of the weight associated with the aircraft's vertical tailplane, whilst ensuring desirable lateral-directional flight dynamics. The use case is a general aviation aircraft for which the wing has been modified using Prandtl's 1933 approach where the span constraint is removed to yield a non-elliptic lift distribution. It is shown that such a lift distribution also contributes to the aircraft's lateral-directional stability and as a result, the size and weight of the vertical tail can be reduced. This study was carried out using an analytical framework that combines early design tools such as XFOIL and AVL deemed to be adequate for subsonic flight. Both cruise and approach configurations are considered. Wing twist distribution and span extension have been calculated using lifting line theory. The study demonstrates the design trade-off needed between flight dynamic modes, such as the Dutch roll mode, and vertical tailplane size when the aircraft is equipped with a wing designed to generate a non-elliptic lift distribution. It is shown that this approach allows a 14% improvement in the lift to drag ratio with 44.34% reduction in V-tail weight. These yield a total of 17% improvement in aircraft range. As for the approach phase it share all the characteristics observed in cruise with the difference that Dutch roll mode is stable for almost all the smaller size of V-tail. Further work requires to focus on the placement of ailerons to remove adverse yaw tendencies.