Rotorcraft rotor blade with sweepback tip

摘要

The rotor blade (1) comprises a leading edge (5) and a trailing edge (6) and is sub-divided into a number of sections which are identified by their distance from the centre (0) of the rotor hub. The first section, extends from the axis of the hub for about 66% of the blade length. A second section extends from the end of the first to about 85% of the blade length. A third section covers the blade length up to 93-97% and a fourth extends from the third to the blade tip. The cord length of the blade increases in a generally linear progression in the first section, reaching a maximum and constant length in the second, decreases in a linear progression in the third, and in a parabolic mode in the fourth. The amount by which the aerodynamic centre is offset relative to the axis in pitch variation is positive and increases in proportion with the distance from the axis of rotation.