Share

Materials

What Kinds of Materials are Used to Make Aircraft?

Several materials can be used for major structures—wings, fuselage, or landing gear, for example—on different types of aircraft.

Airplane rivets.
  • Wood was used on most early airplanes and is now mainly used on homebuilt airplanes. Wood is lightweight and strong, but it also splinters and requires a lot of maintenance.
  • Aluminum (blended with small quantities of other metals) is used on most types of aircraft because it is lightweight and strong. Aluminum alloys don’t corrode as readily as steel. But because they lose their strength at high temperatures, they cannot be used for skin surfaces that become very hot on airplanes that fly faster than twice the speed of sound.
  • Steel can be up to four times stronger and three times stiffer than aluminum, but it is also three times heavier. It is used for certain components like landing gear, where strength and hardness are especially important. It has also been used for the skin of some high-speed airplanes, because it holds its strength at higher temperatures better than aluminum.
  • Graphite-epoxy is one of several types of composite materials that are becoming widely used for many aircraft structures and components. These materials typically consist of strong fibers embedded in a resin (in this case, graphite fibers embedded in epoxy). Thin sheets of the material can be stacked in various ways to meet specific strength or stiffness needs. Graphite-epoxy is about as strong as aluminum and weighs about half as much.
  • Titanium is about as strong as steel and weighs less, though it is not as light as aluminum. It holds its strength at high temperatures and resists corrosion better than steel or aluminum. Though titanium is expensive, these characteristics have led to its greater use in modern aircraft.

Structures Can Buckle under Stress

Sufficient stress will buckle—and in some cases can destroy—a structure. Aircraft are designed to resist such buckling (though some parts and small areas are allowed to buckle to some extent). Buckling depends not only on the physical properties of the structural material but also on thickness and shape.

Ask an Explainer

Q:

Why don’t most airplanes have skin of steel?

A:

Though steel can be up to four times stronger and three times stiffer than aluminum, it is also three times heavier. Aluminum is lighter than steel, because it is less dense. By using aluminum, the skin can be made thicker (to help reduce buckling and fatigue) without adding as much weight.

Submit a Question See All Questions and Answers

Did You Know?

After repeated bending and twisting, a small crack can form and grow where stress is concentrated. That’s why aircraft manufacturers use nondestructive evaluation (NDE) techniques while making an aircraft, and throughout an aircraft's life, to detect cracks. NDE techniques are used to evaluate the properties of materials without causing damage. A commonly used method of NDE is ultrasound scanning, which analyzes echoes from ultrasonic waves to reveal problems inside the material.

Pop Quiz

Which aircraft was the first large airliner to be made with more than 50% composite materials?

A) Douglas DC-3
B) Airbus A380
C) Boeing 787
D) Concorde

Boeing 787: The 787 is the first large airliner to have more than half of its structure (including fuselage and wings) made of composite materials—materials made from two or more ingredients with different physical or chemical properties.  Aircraft often use composite material made of carbon fibers imbedded in epoxy. Compared to wood, steel, or aluminum, it is stronger and stiffer for its weight, improves fuel efficiency, and resists fatigue better.