Question

A model of a helicopter rotor has four blades, each 3.40 m long from the central shaft to the blade tip. The model is rotated in a wind tunnel at 550 rev/min.

(a) What is the linear speed of the blade tip, in m/s?

(b) What is the radial acceleration of the blade tip expressed as a multiple of the acceleration?

Answer 1

(a) The linear speed is

$$v=2πnR=11.7 \text{ km/s.}$$

(b) The radial acceleration of the blade tip is

$$a_g=\frac{v^2}{Rg}=4.1g.$$