No abstract

The flight dynamics and handling qualities of any flexible aircraft can be analysed within the Cranfield Aircraft Accelerated Loads Model (CA2LM) framework. The modelling techniques and methods used to develop the framework are presented. The aerodynamic surfaces were modelled using the Modified Strip Theory (MST) and a state-space representation to model unsteady aerodynamics. With a modal approach, the structural flexibility and each mode’s influence on the structure deflections are analysed. To supplement the general overview of the framework equations of motion, models of atmosphere, gravity, fuselage and engines are introduced. The AX-1 general transport aircraft model is analysed as an example of the CA2LM framework capabilities. The results showed that, according to the Gibson Dropback criterion, the aircraft with no control system lacks the stability and its longitudinal handling qualities are unsatisfactory. Finally, the steps for future developments of the CA2LM framework are listed within conclusions.

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.

No abstract

This article aims to indicate the differences between rigid and flexible wing aircraft flying (FQ) and handling (HQ) qualities. The Simulation Framework for Flexible Aircraft was used to provide a generic cockpit environment and a piloted mathematical model of a bare airframe generic high aspect ratio wing aircraft (GA) model. Three highly qualified test pilots participated in the piloted simulation trials campaign and flew the GA model with both rigid and flexible wing configurations. The results showed a negligible difference for the longitudinal HQs between rigid and flexible wing aircraft. However, significant changes were indicated for the lateral/directional HQs of the flexible wing aircraft. A wing ratcheting phenomenon manifested itself during the roll mode tests, the spiral mode exhibited neutral stability and the Dutch roll mode shape changed from a horizontal to a vertical ellipse. The slalom task flight tests, performed to assess the FQs of the aircraft, revealed the degradation of both the longitudinal and lateral/directional FQs.