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“Inside this need for reduction of aviation environmental footprint, Hybrid Laminar Flow Controlled (HLFC) technology has been identified as one of the more effective and promising technologies for reduction of aircraft fuel consumption”.

Rafael Sánchez
Aerometallic

Aviation industry contributes to economic growth, societal development and cohesion between countries but as in all general world economic system, sustainability and environmental impact has not been well addressed until now.

As the effects of global warming becomes more and more visible, society urges to take effective measures to act on climate change. European Commission take the commitment to becoming the world’s first climate-neutral continent by 2050 (European Green Deal). 

To achieve this great challenge, the European Commission supports aeronautics and air transport sectors towards this green transition. Involvement and commitment of the public and of all stakeholders is crucial to its success. 

Inside this need for reduction of aviation environmental footprint, Hybrid Laminar Flow Controlled (HLFC) technology has been identified as one of the more effective and promising technologies for reduction of aircraft fuel consumption. Aerodynamic studies said that HLFC could reduce between 5% and 9% of fuel consumption on long-range fights. 

However, what is HLFC technology? How it can be explained on a simple way for non-aeronautical engineers? 

When we talk about aerodynamic design, the first thing that comes to mind is the sharp shapes of the sword blade, applied in the design of glider´s wings. This type of aerodynamic design produces low air resistance, minimizing friction drag and turbulences. Actually, this concept in aeronautics is called natural laminar flow (NLF). Air resistance, or viscous drag, is frictional force between the fluid (air) and the surface (aircraft). This drag is much larger in a turbulent boundary than with laminar flow. The energy required to overcome this frictional force in the airplane is a substantial part of the total required to move the airplane through the air. 

Unfortunately, Natural Laminar Flow (NLF) is difficult to be applied on commercial aviation mainly due to transonic speeds and aero surfaces cleanliness requirements. On this case, laminarity conditions with low drag can be still obtain by Hybrid laminar flow control (HLFC) systems. In an HLFC system, the aerodynamic surface becomes a porous surface through which air is sucked to prevent the formation of turbulence. Porous aerodynamic surfaces are getting by laser perforation of millions of microholes on titanium sheets. MULTIPOINT project is focus on microdrilling technologies required for manufacturing this porous wing skins.