Which type of material would NOT typically be used for a propeller blade?

Propeller blades are designed to be strong, lightweight, and able to withstand significant mechanical stresses. While wood, aramid composite, and alloy steel are materials traditionally used for propeller blades due to their favorable properties, plastic does not typically meet the rigorous requirements for such applications.

Aramid composite materials possess a high strength-to-weight ratio and excellent resistance to fatigue and impact, making them suitable for high-performance propeller blades. Wood has been commonly used in earlier designs due to its favorable weight properties and ease of shaping, especially in lighter aircraft. Alloy steel, while heavier, offers exceptional strength and durability, often used in specific high-stress components of propellers.

Plastic, on the other hand, generally does not provide the same level of durability and strength necessary for propellers, especially in the demanding environments they operate in. It is more likely to deform or fail under the mechanical stresses that a propeller experiences during operation, making it an unsuitable choice for this application. Thus, while wood, aramid composites, and alloy steel are well-suited and often utilized, plastic does not typically meet the performance standards for propeller blades.