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The rotor of turbojet engine of an aircraft has a mass 180 kg and polar moment of inertia 10 kg.m2 about the rotor axis. The rotor rotates at a constant speed of 1100 rad/s in the clockwise direction when viewed from the front of the aircraft. The aircraft while flying at a speed of 800 km per hour takes a turn with a radius of
1.5 km to the left. The gyroscopic moment exerted by the rotor on the aircraft structure and the direction of motion of the nose when the aircraft turns, are
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- 1629.6 N.m and the nose goes up
- 162.9 N.m and the nose goes up
- 162.9 N.m and the nose goes down
- 1629.6 N.m and the nose goes down
Correct Option: D
Given, m = 180 kg, I = 10 kg.m², V = 800 km/hr., W = 1100 rad/s, R = 1.5 km = 1500 m
We know that, Gyroscopic couple G = Iωωp 
Effect ⇒ Nose goes down
| G = 10 × 1100 × | 1800 × 18 |
= 1629.63 Nm
G = 1629.63 N.m
