Why are Airplanes Made of Aluminum?
Since the Wright brothers first took flight in 1903, aerospace engineers have worked diligently to find which materials best compose an aircraft's body. Throughout the years, numerous metals were tested and proven ineffective. However, aluminum was eventually recognized as the best performing metal and was widely adopted as the material of choice to construct new planes. Today, 80% of aircraft in use are made primarily of aluminum. In this blog, we will discuss the history of how aluminum came to be the optimal choice in aviation and what makes it such an attractive material.
The first planes to ever take flight were made of a mixture of wood, lightweight steel, aluminum, and fabric. However, it was not until 1915 that an all-metal aircraft would take to the skies. Aircraft designers quickly realized that in order for aircraft to support passengers and cargo, planes would eventually need to be made out of more durable materials. In the 1920s, when airplane racing became a popular sport, pilots and engineers found ways to push aircraft to their limits while constantly looking for innovations to increase performance. As such, a variety of materials were tested and eventually, adopted based on performance. For example, a well-known performance test was when the famous Red Baron flew a welded steel fuselage. By the time WWII came around, nearly every fighter jet was composed of aluminum.
There are several physical properties of aluminum that make it the perfect material for aircraft construction:
- Aluminum is extremely lightweight when compared to similar metals, increasing fuel efficiency and lowering the demand for lift that the aircraft must produce.
- Aluminum is extremely strong for its weight, featuring superior compressive strength and tensile resistance. Aluminum maintains this strength regardless of the temperature in which it is operating. This is in stark contrast to a material like steel, which becomes brittle in colder operating environments.
- Aluminum is extremely corrosion-resistant, which is of great concern as planes function in a wide variety of conditions that make them vulnerable to corrosion.
Of the 80% of aircraft produced using aluminum, the vast majority use two particular aluminum grades: 2024 and 7075. These two metals are similar in their composition but share slightly different characteristics. For example, aluminum 2024 offers less corrosion resistance, weaker weldability, but higher strength. As such, 2024 usually makes up the hydraulic components, wing skins, fuselages, and other smaller components in the engine. On the other hand, 7075 is more lightweight and offers superior corrosion resistance. This material is commonly used to construct fittings, gears, and shafts due to their proximity to corrosive elements.
As aircraft engineers are always looking to improve performance and reduce costs, newer aluminum alloys and other materials are being tested. For example, titanium-aluminide and aluminum-lithium are popular in new and experimental aircraft designs. Titanium-aluminide is easily machined and offers corrosion resistance even in the most extreme temperature environments. Likewise, aluminum-lithium is being considered as a possible replacement to 7075, offering higher strength at a lower density and weight.
Regardless of the material that one chooses to fit their aircraft with, it is important to source the components from a reputable distributor. Aviation Parts Circuit is a leading distributor of new and obsolete parts for the civil and defense aviation industries. Owned and operated by ASAP Semiconductor, we have direct access to one of the industry's largest inventories of in-stock components. Additionally, as an AS9120B, ISO 9001:2015, and FAA AC 00-56B certified and accredited enterprise, we subject much of our inventory to rigorous quality-assurance tests before shipping. Also, as the only independent distributor with a strict No-China sourcing policy, we guarantee that all products are fully traceable or come directly from a trusted manufacturer. Submit an RFQ through our website today and experience the future of aerospace parts purchasing.
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