We’ve come a long way from the early days of aeroplanes, where wood was the most common material used in their design. While it was lightweight and strong, it also splintered frequently and required a lot of maintenance. Now wood is typically only used on small homebuilt airplanes. Anything larger – especially commercial planes – require a strong, reliable metal.
But what type of metal? From strength to weight to durability, there’s so much to consider. Steel is four times stronger than aluminium, but it’s also three times heavier. Aluminium doesn’t corrode as readily as steel, but it also loses strength at high temperatures, such as those outside of an airplane flying twice the speed of sound. Then there’s titanium. It’s about as strong as steel and weighs less too. It also resists corrosion better than both, although it is very expensive, making it cost-prohibitive for a lot of would-be aircraft manufacturers.
The answer is aluminium alloy
Most aircrafts operating today are made from different aluminium alloys. This affords the plane with the light weight and strength of aluminium, while also improving its heat-resistance from the different metals incorporated in the alloy. Each part of the aircraft is made with different compositions of alloy, with the most popular options listed below.
Thought of as the aircraft alloy because of its strength and its excellent fatigue resistance, the 2024-T3 is one of the most popular aluminium alloys used in aircrafts today. It’s typically used for fuselage, wing skins and cowls, as well as for repairs on older planes.
This alloy responds well to welding and has excellent corrosion resistance, with a strength level of mild steel. It’s typically used in the structural body of the aircraft as well as landing mats.
This alloy has higher fatigue strength than most alloys as well as excellent corrosion resistance, particularly in marine applications (think seaplanes), however it is non-heatable and not structural. It’s commonly used to build fuel tanks.
Things to consider
Your build requirements will determine the type of alloy you would use to build an aircraft. Some aircrafts with special needs for strength might replace aluminium with a more costly titanium alloy. For everyday crafts, you should look for aerospace-grade aluminium with good mechanical properties such as those above, all of which we supply. They have all been utilised since the 50s-60s and continued to be used today.