FEATURE BEARINGS, SEALS & GASKETS


ENGINEERED FOR EXTREMES: BEARINGS BUILT TO WITHSTAND AEROSPACE DEMANDS


A crucial component in the aerospace industry, bearings need to withstand extreme loads, temperatures and forces. Carter


Manufacturing looks into the solutions


A


n essential system, where even minor defects or failures could lead to catastrophic consequences, aircraft landing


gear has to meet operational safety and efficiency in the most demanding and extreme conditions. With the typical lifespan of the most popular aircraft models today – the Airbus 320 family and Boeing 737 – being around 20 to 25 years, or 60,000 to 75,000 flight cycles, landing gear maintenance represents around 20% of total maintenance costs as it directly impacts safety, reliability and performance. Bearings are an essential component in landing gear systems, with correct installation critical to harness the full potential of a bearing’s performance and safe operation. This applies to initial installation into an airframe assembly, a main shaft on a jet engine, or a suspension system.


aerospace manufacturing. Specialised bearings are essential for unmanned aerial systems (UAS) like the PHASA-35 from BAE Systems, which encounter extreme temperature variations that challenge conventional bearings. Addressing these issues, Carter collaborated with the Silverthin Engineering team to develop a tailored thin-section bearing solution. Leveraging advanced calculation software, a lightweight, compact and


or drill press to install or replace the bearing. So why are spherical plain bearings the


SPHERICAL PLAIN BEARINGS Due to the extreme loads and forces occurring in landing gear systems, spherical plain bearings are an ideal option. Typically larger than in other aerospace applications, however, this can present challenges in tooling design. Many of the larger landing gear applications require the tooling to be portable, without compromising tool performance, and often cannot be mounted in a pillar drill,


32 DESIGN SOLUTIONS MAY 2025


best option? • Load Distribution – Aircraft landing gear must support the entire weight of the aircraft. As an example, an Airbus A320 has an approximate take-off weight of around 77,000kg. Spherical bearings are designed to handle both radial and axial loads, ensuring that the weight of the aircraft is distributed evenly across the landing gear components. • Articulation – Landing gear components need to articulate or pivot to accommodate the various angles and forces encountered during take-off, landing and taxiing. Spherical plain bearings allow for this, enabling the landing gear to move in multiple directions while maintaining structural integrity. • Shock Absorption – During landing, aircraft experience significant shock loads as they touchdown on the runway. Spherical plain bearings help absorb and dampen these shocks, reducing the transmission of impact forces to the rest of the aircraft structure. • Corrosion Resistance - Aircraft often operate in challenging environmental conditions, including exposure to moisture, salt and other corrosive elements, which is why spherical plain bearings are typically made from corrosion resistant materials. • Weight Considerations - Spherical plain bearings are chosen for their ability to provide the necessary load-bearing capacity, whilst keeping weight to a minimum. Carter Manufacturing is an approved aerospace bearing supplier to industry leading landing gear manufacturers and is accredited to ISO9001, incorporating the requirements of AS9120 with flow down from AS9100. Carter also offers the full range of UNASIS Aerospace Bearing Tools, giving customers the ability to correctly install bearings, first time, every time.


SPECIALISED BEARINGS However, although design to ensure precise and consistent performance in demanding applications, high-altitude bearings play a crucial – yet often under-appreciated role – in


cost-effective design was created that met all operational requirements, showcasing an ability to innovate when tackling aerospace challenges. Temperature changes cause materials like


steel and aluminium to expand when hot and contract when cold, impacting the fit and alignment of the bearing and leading to issues such as increased friction, tightening or loosening of fits, and a reduction in bearing life. These issues can generate excessive heat. Where high- altitude UAS aircraft require lightweight, stable components, it’s essential to manage the thermal-induced stresses from surrounding structures that can impact bearing performance. Temperature-resistant materials and flexible


designs allow bearings to expand and contract without affecting their performance. Selecting materials with appropriate thermal expansion properties reduces the risk of misalignment and damage, improving bearing reliability. In high- altitude aircraft these designs are critical to withstand diverse environmental stresses, such as extreme temperatures and high-altitude pressures, while maintaining system stability. Furthermore, high temperatures can degrade


lubricants, while low temperatures can also hinder their performance. Engineers can select lubricants which can help bearings to function correctly over the required temperature range, thus supporting extended operational endurance and expanding maintenance interval. The advances in bearing technology in projects


like PHASA-35 have pushed the boundaries of sustainable, long duration flights, thanks to developments resulting in their ability to manage the effects of thermal expansion. Engineers continue to set new standards of reliability through precision designs and materials that support proven and long-lasting performance in the most challenging of environments. These improvements not only extend the life of bearings but also pave the way for prolonged, efficient missions, across a wide range of high-stakes applications.


Carter Manufacturing T: 01865 821720 www.carterbearings.co.uk


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