The fuel consumption of an aircraft depends to a large extent on its weight, and every kilogram counts here. The manufacturers and the airlines are therefore working in many areas to save weight. This applies above all to the materials used in aircraft construction. Thus, in addition to special metal alloys, new and lighter materials such as carbon fiber-reinforced plastics are increasingly being found on board the latest aircraft.
In addition to the new materials, bionics is also being used, in which phenomena from nature are transferred to technology, for example to reduce the air resistance of aircraft or to apply design principles from nature. 3D printing is opening up new possibilities for producing components that could not be manufactured using traditional techniques. And: Not only research and development lead to weight savings, but also better organization on board and digital documents.
Click to discover: Climate protection measures on aircraft
Source: Lufhansa Cargo
Digitalization in the cockpit
Thanks to digitization in the cockpit, pilots can dispense with extensive paper documentation. Saves 50 kilograms of weight.
Source: RECARO Aircraft Seating
New materials and designs reduce the weight of the seat rows in a Boeing 737 by more than 330 kilograms.
Source: Lufthansa Cargo
Lufthansa Cargo has more than 5.000 aluminum containers replaced by lightweight containers. This will reduce CO2 emissions by a total of 6.800 tons reduced.
Source: German Aerospace Center (DLR)
Carbon fiber reinforced plastic
Carbon fiber-reinforced plastics weigh less than aluminum and are used in many parts of the aircraft. Here you can see a model of the so-called "slat" made of carbon fiber composite material.
Source: Tom Bruhwiler / travelblogger.ch
Onboard radio networks replace heavy wiring in passenger seats.
The elimination of many kilometers of cables and other components results in a considerable weight saving: In the case of an Airbus A340-600 with 380 seats, this is around 900 kilograms.
Carbon-fiber-reinforced plastic on an engine
By using carbon fiber-reinforced plastics, Rolls-Royce’s latest generation of engines is expected to be around 700 kilos lighter – per unit.
3D printing makes it possible to produce aircraft components from a single casting, for example. Fasteners can then be dispensed with. And 3D printing can be used to replace a solid construction with a ribbed one. So an aircraft with parts from the 3D printer is much lighter.
Source: Lufthansa Cargo
Saving in detail
As part of a clear-out, every single MD-11F in Lufthansa Cargo’s freighter fleet was checked for unnecessary ballast. Since then, each plane takes off about 35 kilos lighter. On the one hand, items were removed that do not necessarily have to be on board, and on the other hand, old equipment was replaced by lighter equipment. In total, this action will save around 250 metric tons of CO2 per year at Lufthansa Cargo.
New materials with less weight
Carbon fiber-reinforced plastic, also known as carbon, is at the heart of new materials for aircraft construction. It is lighter than aluminum and its hardness even surpasses steel. One example of the application is Rolls-Royce’s latest generation of engines, which are expected to make the engines around 700 kilos lighter – per piece.
But carbon is used in many other places as well. This includes, for example, fuselage or wings. As recently as the 1990s, the proportion of carbon fiber-reinforced plastics in passenger aircraft was only ten percent. More than half of the Boeing 787 – better known to many as the Dreamliner – is made of this new plastic.
This reduces kerosene consumption by around 20 percent. In addition to the Dreamliner, half of the Airbus A350 and Bombardier’s CSeries are made of these lightweight materials.
Development of carbon fiber-reinforced plastics in aircraft construction
These and other new materials, such as 3D-printed metallic alloys, titanium, graphene and materials with completely new structures, are one side of the coin. On the other hand, the aircraft industry is also working with old acquaintances such as flax, jute and hemp. These natural materials could be used to good effect in new composite materials, because their production consumes less energy than glass or carbon fibers.
However, there is also a disadvantage: they are more flammable than carbon or glass fibers. Research is currently underway to determine in what form and at what points natural materials can be usefully employed. Another field of research is new and lighter coatings. The Dutch airline KLM, for example, has developed a paint that is 15 percent lighter than previous aircraft paints. In addition, it can be cleaned with soap and water – saving solvents and protecting the environment.
Boeing 787: Less steel and aluminum in use
Big savings in detail
Sometimes all that is needed to reduce weight is a particularly critical look at what is carried on board. This is the case with Lufthansa Cargo’s freighter fleet: All of the company’s MD-11Fs have been inspected for unnecessary ballast. More than 300 individual parts were removed and weighed for this purpose. Then every part was examined for possible weight savings and swapped out. As a result, 35 kilos could be saved per aircraft.
Since then, for example, new and lighter flashlights and seat covers have been installed on board. The 35 kilograms saved per aircraft may not seem like much at first glance, but Lufthansa Cargo saves 80 tons of fuel and 250 tons of CO2 per year in this way Carbon dioxide is a colorless and odorless gas, a component of the air and a greenhouse gas. It is u.a. released during the combustion of fossil fuels. a.
Another example are the well-known and large pilot cases that used to be in every cockpit. They weighed up to 18 kilos. Today, pilots use the Electronic Flight Bag, which electronically stores all navigation charts and documents and weighs only a fraction of the weight of a normal flight bag. But there is another area in the cockpit where things are lighter today: Extensive paper documentation is now available electronically, saving around 50 kilograms in weight – aircraft by aircraft, flight by flight.
The clear-out on the MD-11F
Electrical cables: less length, less weight
In private households and offices, data transmission via conventional power lines is already commonplace. It is still relatively new in aircraft. Its use would be particularly worthwhile in commercial aircraft, where there are literally tons of cables, thus saving weight.
There are more than 500 kilometers of electrical cables in an Airbus A380. And they weigh a whole eight tons! Around 40 percent – that’s three metric tons – have as their sole task the transport of data. However, there is no need for dedicated lines, because existing cables can take over the task.
Since the process is not new in principle, the technical hurdles are rather small. However, the hurdles are justifiably large when it comes to the necessary approvals, which are not yet available. That’s not surprising, because safety always comes first in air travel.
The elimination of heavy cables saves kerosene
And in the future: metallic structures
Aircraft manufacturer Boeing is working on a new metal that could revolutionize structural engineering. Microlattices are metallic structures whose smallest parts are a thousand times thinner than a hair. This makes Microlattice a material that is a hundred times lighter than Styrofoam.
The principle on which the new material is based becomes clearer if one realizes that Microlattice consists of 99.99 percent air. The individual tubes that make up the metal structures are also hollow and thus resemble the structure of bones. The new material could be used for interiors, for example, but also for the fuselage. This new material makes it possible to save weight, which in turn leads to great fuel savings.
Novel structure: Microlattice
The age of 3D printing has begun
An Airbus A350-900 has an empty mass of about 130 tons. Does it depend on a ton more or less? Yes, because 100 kilograms less save 14 liters of kerosene on a route from Berlin to Tenerife. To reduce the weight of an Airbus of this design by one ton, only 140 different components would have to be 3D printed in the future. To put it in perspective: an aircraft of this type consists of more than three million parts.
3D printing is a manufacturing process that makes very strong yet lightweight components possible. This saves weight and thus kerosene during the flight. Aircraft parts from 3D printers weigh up to 55 percent less than conventional components while reducing raw material consumption by up to 90 percent.
Just how far technology has already advanced can be seen in a very special model-making project: Airbus has unveiled the small and functional "THOR" airplane, which was assembled entirely from parts from the 3D printer. From the outside, the plane looks like other planes, but beneath its hull are bionic frameworks that support the fuselage. A lot of weight can also be saved in this way, and so the 3.5-meter-long airplane weighs only 20 kilograms.
THOR – The airplane from the 3D printer
Another example of the combination of 3D printing and bionics, i.e. the transfer of phenomena from nature to technical applications, is the prototype of a partition wall for the Airbus A320. It divides the rear kitchen and passenger area and, at 35 kilograms, weighs just over half as much as the original. The model was bones, which are hollow but very stable. 3D printing is ideal for such tube designs because it builds layer by layer.
Bionic structures from the 3D printer
New materials, structures and manufacturing processes lead to less weight and greater efficiency in fuel consumption.