Plastics are found in commercial planes, military aircraft and even satellites. While each plastic has unique purposes, it is also crucial to remember not all plastics are suitable for use in this field. High-performance plastics satisfying various standards are required to maximize performance and assure safety.
Plastics for Aerospace Applications
A wide range of parts in the aerospace industry are made from plastics. Engineers first experimented with vinyl materials to see if rubber parts, such as fuel-tank linings, could be replaced by plastic ones. Since then, aerospace engineers have found other numerous ways to substitute not only rubber but also glass and metal with plastics.
Here are some common applications of plastics in the aerospace industry:
- Aerostructure: wings, doors, pipes, leads, cable ducts
- Components: fasteners, bearings, bushings, refueling and fuel systems
- Control systems: landing gear
- Cabin interior: seating, cabin lighting, drinking water systems
- Propulsion systems: engines and components
- Satellites: antenna covers, bearing bushes, sliding elements
Benefits of Plastics
Plastics offer many advantages that other materials do not. For example, plastics reduce manufacturing and operating costs. In general, plastic can be manufactured more economically than other materials. Plastics are also much lighter, especially compared to metals and glass. For instance, plastics are about 50% lighter than aluminum. Because heavier planes, like those made of aluminum, require more fuel to move, lighter planes, like those with plastic components, reduce costs, saving both money and energy.
Plastics stand up in harsh conditions better than other materials. Unlike metals, they are resistant to corrosion and more impact-resistant than glass. Plastics also provide electrical insulation; in fact, some plastics have almost zero conductivity. On top of all these advantages, plastics allow superior design flexibility.
Choosing the Right Type of Plastic
While plastics offer a variety of advantages, not all plastics are suitable for aerospace applications. Since only high performance plastics qualify for certain uses, keep the following considerations in mind:
- Is this plastic material inherently flame resistant?
- Can it endure high temperatures?
- Does it have high chemical resistance, even at high temperatures?
- How likely is it that this material will change its characteristics, such as shape, area and volume, with temperature alterations?
- Is this type of plastic a good electrical insulator?
- How much gas does it release in a vacuum?
PEEK, or Polyetheretherketone, and Torlon are two of the most common plastics used in the aerospace industry.
PEEK or Polyetheretherketone is a semi-crystalline, organic thermoplastic polymer. It is one of the highest performing thermoplastics with low flammability and creep resistance. PEEK can perform under high temperatures (up to 450 °F) and endure high water pressure. As a result, it can often be found in valve seats and pump gears.
Torlon is the highest performing, melt-processible thermoplastic. Torlon’s exceptional mechanical strength makes it appropriate for applications in severe situations, including temperatures up to 500 °F. In addition, Torlon has good creep, thermal, chemical and flame resistance as well as low thermal expansion. Torlon is often used to replace metal in tough jobs.
Plastics are loved in the aerospace industry for their unique properties, quickly replacing both glass and metal. This change has helped manufacturers save energy and money while increasing safety.