Extensive testing has resulted in E8T89, a new Ethylene Propylene Diene Monomer (EPDM) seal material from Trelleborg Sealing Solutions. According to the company's research and development team it offers 'the best of everything' that an aircraft operator could require of a sealing material for aerospace hydraulic applications. Specifically it provides a unique combination of outstanding elasticity at -55 °C/ -67 °F with unrivalled compatibility in all commercially available phosphate ester hydraulic fluids, ensuring extended long-term sealing performance.

"E8T89 is engineered to conform with the wide range of specifications that apply to hydraulic aircraft systems," says Guy Burridge, Product Manager, Trelleborg Sealing Solutions, Tewkesbury. "Because the material is compliant with all parts of these standards relating to seals, our tests have shown that this EPDM performs better on key criteria than any other material of its type on the market."

Importantly, E8T89 meets the requirement for low temperature performance that has become more significant in aerospace hydraulic applications. Most standards now demand materials that operate effectively at an extremely low limit of -55 °C/ -67 °F, in-line with minimum temperatures faced at high altitudes.

The material also ensures long life as it demonstrates compatibility with demanding phosphate ester hydraulic fluids, such as Hyjet and Skydrol®. In particular, it stands up to potential interchange between different hydraulic fluids during maintenance. In addition, E8T89 provides excellent long-term retention of mechanical properties and facilitates opportunities for stock reduction through part number rationalization.

EPDM E8T89 offers compliance with NAS 1613 Rev 5, NF L 17-241 41B8 and all other relevant national and international standards. It is available in all O-Ring sizes, as gaskets, molded parts or rubber-to-metal bonded components.