Performance and economic assessment of a wing-integrated hybrid laminar flow control system

Abstract The energy efficiency of emerging aircraft designs plays a key role, not only in reducing environmental impact, but also in reducing operating costs in the anticipated rise in fuel prices. The European Clean Sky 2 project HLFC-Win is investigating the feasibility of hybrid laminar flow control (HLFC) technology integrated into the outer wing leading edge for a long-haul aircraft. HLFC technology reduces aerodynamic friction drag by means of suction of the boundary layer through a micro-perforated skin to achieve laminarity and thereby improving aircraft performance. However, integrating such a system is not without its drawbacks, as the integration has an impact on the geometry, mass, aerodynamics and engine offtakes that need to be considered. Therefore, the aim of this current work is to assess the HLFC system based on a fair, objective and transparent comparison between the HLFC aircraft and an aircraft of the same technology level without HLFC. The assessment of the HLFC system is twofold, firstly estimating the mission-based performance at the overall aircraft level and secondly performing a lifecycle simulation with three scenarios to determine realistic fuel and cost savings. The mission-based performance assessment indicates a block fuel reduction of over 3 % for the design mission which averages 1.6 to 2.5 % considering a realistic route scenario and expected degradation. The economic assessment suggests a dependency on the scenario chosen, ranging from a 0.7 % increase in total cost (in an unfavourable scenario) to almost a 1 % reduction in total cost (in a favourable scenario), equivalent to $15 million saved per HLFC aircraft over its lifetime. These results support the commercial viability of HLFC technology, which offers significant aerodynamic and fuel efficiency improvements and operating cost savings to the aviation industry. Importantly, no critical barriers were identified for the integration of HLFC technology, further underscoring its potential to improve aircraft performance.