How fiber-reinforced plastic makes flying more environmentally friendly
Exclusively for K-MAG
Plastics make aircraft lighter and therefore lower in emissions. Copyright: PantherMedia/ewastudio
Around 10,000 m altitude, speeds of almost 1,000 km/h, outside temperatures as low as -60°C. One of the reasons why we as airline passengers don't notice any of this is because of plastics. These are not only mechanically and chemically resistant, but also lightweight. And lighter aircraft cause fewer CO2 emissions, which is of great importance for achieving climate targets.
Almost all components of an aircraft today are made of fiber-reinforced plastics (FRP). These are synthetic resins reinforced with glass or carbon fibers. This material meets the stringent requirements of the aviation industry. The fact that aircraft are becoming lighter, more powerful and more reliable is therefore also a credit to the chemical and plastics industry.
Fiber-reinforced plastic – a success story
Fiber-reinforced plastics were first used in aviation nearly 100 years ago in zeppelins. Copyright: PantherMedia/keko64 (YAYMicro)
The first use of plastics in aviation now dates back almost 100 years. A very early FRP consisted of the bakelite resin phenol-formaldehyde. This incorporated layered paper webs pre-impregnated with a resin for reinforcement. It was used in the airship "LZ 127 Graf Zeppelin", which entered service in 1928. The walls of the passenger lounge were made of 0.8 to 1 mm thick sheets of FRP. Due to the positive experience with regard to corrosion and moisture absorption, the material was also to be used for subsequent airships. Here, the floors and walls of the washrooms and kitchen were also to be clad with FRP sheets.
At the end of the 1950s, major progress was made once again: The "Phoenix" was the first glider made of glass fiber reinforced plastic (GVK). Thanks to lower weight and improved aerodynamic properties, it was possible to achieve flight performance and glide ratios that had previously been unthinkable.
Finally, in the early 1970s, Boing and Airbus began testing the first carbon fiber reinforced plastic (CFRP) components. In 2011, the Boeing 787 Dreamliner entered service – making it the first long-haul commercial aircraft made of 50 percent plastic. A few years later, Airbus followed suit with its A350, which achieves an FRP content of 52 percent.
Plastic, the all-round talent for aircraft
Aircraft today are usually made of more than 50 percent plastic. Copyright: svitlanah
Today, the aviation industry is particularly in the public eye when it comes to environmental and climate protection. The aviation industry has set itself the goal of halving CO2 emissions by 2050 compared with 2005. One approach to saving fuel and thus CO2 is lightweight construction and the associated use of lightweight materials that also meet all the requirements relevant to aviation - and today these are primarily FRP made of carbon. With optimum design, a weight reduction of around 50 percent can be achieved with this material compared with aluminum.
In addition to fuel savings, the reduced weight has another effect: lighter aircraft require more filigree landing gears and smaller tanks. This saves material and compensates for additional costs incurred by FRP. Other advantages of the material include better processability compared with other materials, high chemical and corrosion resistance, high mechanical stability, good sliding properties, low maintenance, temperature resistance and inherent flame retardancy.
Plastic is found in a wide variety of places in aircraft: GVKs have become established in the aircraft interior, while CFRPs are used in the fuselage. Fiber-reinforced plastics are used in fastening elements, seals, cabin fittings and trim parts as well as in propulsion or drinking water systems.
Plastics processing companies such as Röchling SE & Co. KG, igus GmbH or Ensinger GmbH offer materials that meet the high requirements applicable to aviation and also fulfill the fire protection standards FAR 25.853 and UL94 V0.
A look into the future of aviation
Plastics are found not only in the interior of an aircraft, but also in its engines. These must be able to withstand extreme stresses. Copyright: svitlanah
The aviation industry is growing - and growing rapidly. This naturally poses a number of challenges for the industry. For one thing, passenger aircraft have to be manufactured at rates of sometimes more than 70 deliveries per month. For this reason, intensive research is now being carried out to optimize series production – for example, with the development of new resins that cure faster.
On the other hand, the aviation industry must strive to significantly reduce CO2 emissions in order to achieve climate targets. Lufthansa Technik and BASF achieved a breakthrough in a joint project last year: Thanks to the new surface film "AeroSHARK," which is modeled on the fine structure of shark skin, an aircraft's frictional resistance in the air is to be reduced, thereby also lowering fuel consumption. A friction reduction of more than one percent is expected for use on ten Boeing 777F aircraft operated by Lufthansa Cargo. What sounds little corresponds to an annual saving of almost 11,700 tons of CO2.
3D printing also offers great potential. It can be used to produce aircraft components from a single casting, eliminating fasteners. Since a solid construction method can be replaced by a ribbed construction method, an aircraft with parts from the 3D printer becomes much lighter.
But there are already successes to report today, too: German airlines have been able to reduce their fuel consumption per passenger per 100 kilometers by a good 43 percent since 1990. Whereas this figure was 6.3 liters in 1990, in 2019 it averaged just 3.56 liters per passenger. This success is due in no small part to plastics.
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