New aeroplane wing flap improves flight performance
Next time you’re on a plane, take a look out the window. An important concept in successful aerodynamics is laminar flow: the way that air travels above and below the wing. The friction of the air against the wing determines this flow, and aeroplane designers want to reduce it as much as possible. Not only does drag hinder flight performance, it also pushes up carbon emissions. In the EU-funded SWING project, a consortium developed an innovative solution, creating a new flap at the front of the wing that offers increased laminar flow control. “The objective of the project was to validate its industrial feasibility, meaning its manufacturability, and we have reached the required level of technology maturity,” says Christophe Cornu, research project manager at Cetim Nantes and SWING project coordinator. In addition to designing the new wing flap, the SWING project also developed a more efficient way to manufacture flaps, using an advanced thermoplastic implementation process.
Deflecting insects to improve laminar flow
The wing flap is known as the Krueger flap, which offers increased control of laminar flow, reduces the weight of the wing, and is also recyclable – adding more benefits for the aerospace industry. The Krueger flap functions as a ‘deflector’ while in the extended position, deflecting insects away from the wing that could compromise laminar flow. The complex geometry of the flap, achieved by laser welding a thin thermoplastic composite prepreg tape, is expected to reduce the operations and therefore the costs of future composite parts compared to current industrial solutions. The reliability of the process will be a key factor in reducing manufacturing costs of composite parts in the future. This successful process, developed under the SWING project, includes speeding up the raw material laying speed, and reducing loss.
Thermoplastic process for wing creation
One of the main developments was the implementation of the thermoplastic process for manufacturing the Krueger flap. “The main advantage of thermoplastic polymer materials is their recyclability compared to other materials,” explains Cornu. “Also, the processing of thermoplastic materials requires fewer additional operations and therefore costs could decrease in the future when the technology is fully developed.” To create the thermoplastic polymers for the Krueger flap, the team used a robot with a laser head to consolidate the part in situ. This avoids additional processes, and offers greater reliability and repeatability, which improves the overall quality of the part.
Improving technology maturity
Now that the part has reached technology readiness level 4 (TRL 4), the wing design and process will be put through functional tests on the ground. “The kinematic of the Krueger flap will be checked via its interfaces with the wing,” adds Cornu. This process will lead to validation of the product in the laboratory over the next few years. The most important thing was to find the right manufacturing strategy for the part, he notes. This included developing the parts as several components to get a structure resistant to necessary mechanical constraints and making the complex overall form ‘developable’: in a way that the material can be consolidated together during laser welding operation by the robot. “Materials and processes are progressing very quickly, and this will give more enviable solutions to the planet,” says Cornu.
Keywords
SWING, laminar, flow, aeroplane, friction, air, flow, flap, deflect, insects, improve, technology
