The aviation industry is one where material science and engineering are pushed to their limits. Broad spectrum durability, economy, weight, machinability and desirable physical characteristics all must be considered when selecting components for aircraft. Given these intense demands, it’s no surprise that the industry has turned its focus to high performance polymers in recent years. That trend really took off at the turn of the millennium, as the amount of high-performance polymers in the industry doubled between 2000 and 2010. There’s good reason for that, as polymers like PEEK and Torlon can deliver what aviation manufacturers need from their components.
Planes and Polymers
What is a high-performance polymer? Put simply, it’s a polymer marked by its superior temperature stability, which far exceeds that of standard and even engineering thermoplastics. High-performance polymers also offer better chemical resistance and mechanical properties.
How is that relevant to aviation manufacturers? After all, aircraft have been constructed from metal for decades. It’s true that metal will also offer a level of structural strength and stiffness that polymers cannot, which means that metal will be used for parts such as airframes into the foreseeable future, but high performance polymers are quickly replacing metals in many other ways. That’s because polymers provide the following advantages:
- Weight reduction – Fuel is expensive, and the heavier the aircraft, the more fuel it will take to keep it in the air. For every pound of weight added to a plane, it will cost an additional $1,000 in fuel over the life of the aircraft. Metals are heavy – polymers are not. In some instances, polymers are much lighter than their metal counterparts, even up to 10 times lighter. And this comes with no tradeoff in durability, allowing aviation manufacturers to make deep cuts into their operating costs of their planes.
- Across the board durability – PEEK and Torlon are extremely inert durable, and are especially fit for the kind of environments that are common in the aviation industry. For example, PEEK and Torlon can withstand extended exposure to aviation fuels and most other chemicals. They also come with inherent fire resistance and resist do not generate smoke and gases other polymers do as well. Beyond their chemical and corrosion resistance, high-performance polymers are resilient even under enormous pressure, with the ability to bounce back from powerful impact and abrasive forces to components like cables and hoses.
- Extensive processability – PEEK and Torlon are among the most durable polymers that can still be melt processed in a variety of ways. They can be injection molded or machined from extruded shapes to precision, giving aviation manufacturers a range of manufacturing options. This versatility workability means that PEEK and Torlon components can be designed to fit highly precise machined one-offs, or molded en masse to keep production unit costs low.
- Superior physical properties – High performance polymers are extremely durable even at temperature extremes. For example, Torlon is stronger at 400F (200C) than most thermoplastics are at room tempearure. It also offers impact resistance under very low temperature conditions and is often specified for cryogenic service. Both PEEK and Torlon offer excellent sealing characteristics, which is essential for preventing air and fuel leaks.
This combination of standout properties is impossible to beat and is why the use of high-performance polymers is growing in many parts of the aviation market. They can be integrated into almost every aviation system, from the craft’s fuselage to small engine components to electronics and even cabin seating. Specifically, here is where PEEK and Torlon can be found on aircraft:
- Aerostructure – Bearings and bushings, reinforcement for composite panels including hard points and thermal isolators and fasteners.
- Systems and support – Actuation and controls, including thermal and power management, engine control, landing system, sensors, de-icing, flight control, door opening and closing controls, cable protection.
- Cabin interior – Seating, chilling system, oxygen system, cabin lighting, drinking water systems, vacuum waste systems and cargo equipment.
- Propulsion – Fuel systems, turbines and nacelles.
Clearly, high-performance polymers like Torlon and PEEK are useful in a wide range of aviation applications. Their excellent longevity, economy and versatility have them out in front of competing materials, including metals, and guarantee that they will be needed in aviation applications for the foreseeable future.