Question

A helicopter moves horizontally in the x direction at a speed of 120 mi/h. Knowing that the main blades rotate clockwise when viewed from above with an angular velocity of 220 rpm, determine the instantaneous axis of rotation of the main blades.

Answer 1

The instantaneous axis of rotation=

x = 0 ; z = 8.4 ft

Step-by-step explanation:

Given:

Speed of helicopter, Vo= 120 mi/h, converting to ft/sec, we have:

`(5280 * 120)/(60*60)`

= 176 ft/s

Angular velociyy, w = 220 rpm, converting to rad/sec, we have:
`(200*2*pi)/(60) =20.95 rad/s`

The helicopter moves horizontally in the x direction at a speed of 120 mi/h, this means that the helicopter moves in the positive x direction at 120mi/h

To find the instantaneous axis of rotation of the main blades, we have:

Where Vc = 20.95 rad/s

Vo = 176 ft/s

`z = (V_0)/(V_c) = (176ft/s)/(20.95rad/s)`

= 8.4 ft

Therefore the axis of rotation=

x = 0 ; z = 8.4 ft