Section of a composite rotor blade from a Westland 'Lynx' helicopter, 1985.
© Science Museum / Science & Society Picture Library
A rotor blade has to both support and propel a helicopter. It therefore has to be very strong and at the same time appropriately flexible. The required strength is obtained by using layers of different kinds of composite plastics, and aluminium along with foam and honeycomb inserts. Complex shapes that would otherwise be imposible can also be moulded. Carbon fibres are extremely strong and stiff because of the alignment of their crystalline structure. This makes the material highly suitable for use in the manufacture of aircraft wings and fuselages, specialist engineering and sports equipment, and in jet engines and rockets, where strength at high temperatures is required.