If each of the three rotor helicopter blades is L = 3.69m long and has a mass of m = 159kg, calculate the moment of inertia of the three rotor blades about the axis of rotation.

Answer 1

I need to know how far the center of mass of a blade is from the axis.
If we assume the blade is a uniform rod with cg at its center (unlikely) then the moment of inertia about its end is:
I = (1/3) m L^2

so for 3 we have just
I = 1 m L^2 = 159 * 3.69^2
= 2165 kg m^2