Question

Rotating unbalance is also impportant in rotorcraft such as helicopters and prop planes. The tail rotor section of the helicopter shown consists of four blades, each of mass 2.3 kg, and an engine box of mass 28.5 kg. The center of gravity of each blade is 170 mm from the rotational axis. The tail section is connected to the main body of the helicopter by an elastic structure. The natural angular frequency of the tail section is observed as 135 rad/s. During flight, the rotor operates at 900 rpm. What is the vibration amplitude of the tail section if one of the blades falls off during flight ? Assume damping ratio of 0.05. Ans. 9.25 mm

Answer 1

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