A new bracket technology suitable for use in hydraulic and fuel brackets for the wings, center box and fuel tanks of aircraft can reportedly result in significant weight reduction of at least 40% compared to metals. Enhancing the fuel economy of aircraft further, along with cost savings and streamlined manufacturing, has been a principal driver for the bracket manufacturer Denroy Plastics Ltd.

The UK-based precision plastics injection molding specialist developed the optimized brackets in close collaboration with Bombardier and polyetheretherketone (PEEK) supplier Victrex. Made of an electrostatically dissipative Victrex PEEK-ESD polymer, with proven performance in harsh environments including aggressive aerospace fluids, the bracket is specified in commercial aircraft such as Bombardier's C-Series, Global, and Learjet aircraft.

The target was clearly defined: To replace small to medium-sized machined aluminum and titanium brackets intended to last for the life of the aircraft even though many of these brackets are constantly immersed in fuel. In addition to developing a reliable solution, weight and cost savings were keys to success. With cost savings and streamlined manufacturing among the advantages of using injection molded polymers, the new bracket technology is now being introduced to the aircraft industry.

Denroy has adopted a consistent approach to replacing metal brackets with Victrex's PEEK resin. "Here at Denroy, we've invested in a manufacturing cell dedicated to the production of PEEK brackets. We have now developed optimized molding processes and invested in new equipment. Victrex´s advice and support have been very valuable in the delivery of a durable bracket weighing at least 40% less than the metal design," noted Jim Knowles, Sales & Marketing Manager at Denroy Plastics.

For Bombardier, the new bracket technology results in significant cost savings in fuel and lower CO₂ emissions. In addition, cost savings during manufacturing can be achieved due to consolidated parts, integration of complex shapes and geometries, elimination of secondary processing (e.g., machining and painting), as well as by reducing both scrap material and production time.

"Victrex is committed to address specific challenges in aerospace such as weight reduction and simplified manufacturing by providing a range of PEEK grades that enable this, including the Victrex PEEK-ESD polymer. The proven track record of Denroy in the automotive industry has enabled them to adapt their knowledge and experience to the design and production of aerospace components", says Tim Herr, Aerospace Strategic Business Unit Director at Victrex. Victrex is known for its polyaryletherketone (PAEK)-based solutions specified for use in aerospace and has just recently introduced a new hybrid molding technology for loaded brackets.

In the case of the Denroy brackets, Victrex used proprietary fillers, which do not break down under shear, to support design freedom - a critical feature if the brackets were to be optimized to their fullest extent. This reportedly allows moldings to be produced under the optimum molding conditions without affecting the electrostatic discharge properties of the components.