Helicopter blades are made out of various materials, including titanium, aluminum, stainless steel, carbon fiber, and fiberglass. These materials are mixed together to form a composite material in order to take full advantage of each material’s unique properties and strengths.
This hasn’t always been the case, though. It only applies to the modern helicopters you see flying today. Helicopter blades have been made from a variety of materials over the years.
A Short History of the Materials Helicopter Blades Are Made From
The very first helicopters like the Bell 47, which was introduced in 1946 and was the first helicopter certified for civilian use, had blades that were made out of wood.
Wood rotor blades may have been strong and flexible and worked well at the time, but they certainly had their pitfalls. Wooden blades could easily be damaged beyond repair by the environment and the elements, such as rain, dust, and stone. This often resulted in a dangerous out-of-balance rotor system, which caused lateral vibration and made starting up the helicopter challenging.
Additionally, as the blades were flown as sets, if one was damaged then you had to replace both, which was hardly efficient or cost-effective.
Due to the problems that were inherent with wooden blades, metal blades began to appear. One of the great advantages of switching to metal blades was that the individual blade could be replaced instead of the whole set.
Metal blades weren’t perfect, though. If a metal blade cracked or was damaged in an important area it could result in catastrophic failure. A pilot wouldn’t even have any prior warning so would be unable to take any evasive action.
Soon after, the introduction of honeycomb construction appeared and was an important milestone in the design of helicopter blades. This allowed the blades to be designed in a better shape that increased performance while also creating greater strength.
Non-Metallic Composite Blades
Metal blades may have been a step-up over wood, but their sudden weakness of being damaged or cracked in a critical area couldn’t be overlooked. Non-metallic blades made out of composite materials were therefore introduced and gave plenty of warning if a problem started to develop.
The first non-metallic blades utilized fiberglass skins that could prevent catastrophic failure in two ways. One was that there would be visible damage to the blade itself, and the other was there there would be a gradual increasing vertical vibration that pilots could notice.
Today helicopter blades are made out of composite materials, including titanium, aluminum, stainless steel, carbon fiber, and fiberglass that cover a foam or Nomex core. This has resulted in several improvements to helicopter rotor-blade design, with their very slow failure arguably being the most important.
This is down to the composite blades being designed in a way that uses crisscrossed layers of fabric to resist cracking. The blades also do not corrode and can be made with fewer joints and fewer parts.
When it comes to performance, composite blades also come out ahead due to the great deal of blade stiffness and flexibility that designers can take full advantage of to create custom molds. This gives designers a lot of room to create helicopter blades that can reduce vibration, produce as much lift as possible, reduce drag as much as possible, be as efficient as possible, last as long as possible, and closely match actual blade performance to their paper designs.
However, helicopter composite blades can be expensive to manufacture, requiring more money and effort during the fabrication and finishing process. Ultimately, though, this increased cost and effort is more than worth it in the long run for both safety and performance purposes.