Case Studies - Aviation

QinetiQ's multi-disciplinary optimisation (MDO) capability is helping Airbus consider the future shape of high speed air travel.

Despite the end of scheduled Concorde services, there is continued European interest in high-speed civil transport (HSCT) aircraft. As Concorde was not an economic success, the aim is to determine whether a Concorde replacement aircraft can be made financially viable in terms of passenger numbers, range and the in-service costs such as fuel burn, as well as manufacturing costs and environmental issues such as noise and pollution.

The traditional approach to the configuration design of aircraft has been two-tier in nature. Simple modelling of geometry, aerodynamics, structures etc. is used to identify promising concepts. These concepts are then subject to analysis and refinement in each discipline area, using the best methods available.

While this approach may produce a design that is optimised with respect to a single discipline, it is less likely to identify the design that makes the best use of all the relevant technologies. An MDO approach using high-fidelity analysis methods concurrently thus has the potential to identify improved designs, relative to the traditional process.

Figs 1a & 1b: Starting design - aerodynamic and structural results

Figs 2a & 2b: Final design 1 - aerodynamic and structural results

Figs 3a & 3b Final design 2 - aerodynamic and structural results

QinetiQ scientists and engineers, in conjunction with their counterparts in DLR (Germany), NLR (The Netherlands) and ONERA (France), applied their detailed knowledge of MDO techniques to the HSCT aircraft problem. The work showed how the optimum wing planform shape varies with cruise Mach number, and also the trade-offs between aerodynamic performance and structural mass. The results demonstrated improvements in aircraft range (upwards of 10%) which could be expected through the application of MDO, rather than traditional, sequential discipline-based design. The work was presented in detail at the 10th AIAA/ISSMO Multi-Disciplinary Analysis and Optimisation conference in Albany, New York in August 2004.

The demonstration of the MDO techniques and the results therefrom help Airbus consider the methods by which future aircraft can be designed, and the potential advantages of novel planforms for different cruise speeds.