Influence of Off-Design Performance on the Design of Aircraft with Laminar Flow Technology

Laminar ow is among the most discussed technologies towards satisfying the ambitious goals for more fuel e cient aviation. Both passive as well as active laminar ow control systems are sensitive to external in uences and system failures. A sudden degradation of laminar ow immediately results in loss of ight performance. Such o -design cases have to be considered already in preliminary design synthesis for correct sizing of the aircraft. In the scope of this paper, an approach is presented that incorporates o -design cases of laminar aircraft into preliminary design synthesis. The authors chose to use the extended-range twin-engine performance standards (ETOPS) as framework for deriving operational standards for aircraft with laminar technology. Di erent requirements for minimum o -design performance are derived that directly impact overall aircraft design synthesis. In a case study, the sensitivities of the overall design synthesis towards these o design requirements are discussed. Design parameters such as maximum take-o weight, block fuel, as well as the aircraft economics are used for evaluation of the di erent concepts.