Question

a model of a helicopter rotor has four blades, each 3.40 m in length from the central shaft to the tip of the blade. The model is rotated in a wind tunnel at 550 rev/min. A) what is the linear speed, in m/s of the blade tip? B.) what is the radial acceleration of the blade top, expressed as a multiple of the acceleration g due to gravity?

Answer 1

angular velocity, ω
= 550 rpm
= 550 * 2π /60
= 55π/3 radians/s

radius, r
= 3.4 m

A.
Linear speed, v
= r ω m/s
= 3.4 * 55 π/3 m/s
= 195.83 m/s

B.
radial acceleration
= r ω²
= 3.4 (55π/3)² m/s/s
= 11279 m/s/s
= 11279 / 9.81 g
= 1149.7 g