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.

Wingtip folding is a means by which an aircraft’s wingspan can be extended, allowing designers to take advantage of the associated reduction in induced drag. This type of device can provide other benefits if used in flight, such as flight control and load alleviation. In this paper, the authors present a method to develop reduced order flight dynamic models for in-flight wingtip folding, which are suitable for implementation in real-time pilot-in-the-loop simulations. Aspects such as the impact of wingtip size and folding angle on aircraft roll dynamics are investigated along with failure scenarios using a time domain aeroservoelastic framework and an established system identification method. The process discussed in this paper helps remove the need for direct connection of complex physics based models to engineering flight simulators and the need for tedious programming of large look-up-tables in simulators. Instead, it has been shown that a generic polynomial model for roll aeroderivatives can be used in small roll perturbation conditions to simulate the roll characteristics of an aerodynamic derivative based large transport aircraft equipped with varying fold hinge lines and tip deflections. Moreover, the effects of wing flexibility are also considered.

It is well known that increasing wing span leads to improved aerodynamic performances. To comply with airport infrastructure limits, ground folding wingtips are implemented as a solution for wing span extension. To further justify the mechanism's weight penalty the concept of in-flight folding is investigated here. A time domain aeroservoelastic simulation framework is used to asses its impact on lateral flight dynamics. An established system identification method, was used to derive key lateral aerodynamic derivatives and investigate the aircraft's roll handling qualities. A range of wingtip deflections and various flight conditions were used to generate a sufficiently large database of coefficients to assess the effect of wingtip morphing as a function of airframe flexibility and flight conditions. Results show that overall, small changes in lateral aerodynamic derivatives are introduced with wingtip morphing. Different trends in aerodynamic derivatives were identified as a function of flight condition and wingtip deflection, leading to the derivation of prediction models to replace the aerodynamic derivatives database.

This paper provides an overview of the work conducted as part of the Cranfield BEAm Reduction and Dynamic Scaling (B R D S) programme, which aims to develop a methodology for designing, manufacturing and testing of a dynamically scaled High Aspect Ratio (HAR) Wing inside Cranfield 8'x6' wind tunnel. The aim of this paper is to develop a methodology that adopts scaling laws to allow experimental testing of a conceptual flexible-wing planform as part of the design process. Based on the Buckingham π theorem, a set of scaling laws are determined that enable the relationship between a full-scale and sub-scale model. The dynamically sub-scaled model is manufactured as a combination of spar, skin, and added mass representing the stiffness, aerodynamic profile, and aeroelastic behaviour respectively. The spar was manufactured as a cross-sectional shape using Aluminium material, while the skin was manufactured using PolyJet technology. Compromises due to the manufacturing process are outlined and lessons learned during the development of the sub-scaled model are highlighted.

The impact of in-flight folding wingtip on roll characteristics of aircraft has been studied in the past. In this study, a handling qualities assessment carried out to de-risk further development of such a device. A specialised flight simulation campaign is prepared to evaluate the roll dynamics in different morphing configurations. Various manoeuvres, including the Offset Landing Manoeuvre and herein presented Slalom and Alignment Tracking task are used. Cooper Harper Rating scales and flight data analysis are used to collect pilot opinion and validate pilot-in-the-loop simulation results. This example is used to demonstrate the use of the slalom and Alignment Tracking manoeuvre for lateral dynamic assessment.