GYROSCOPES Aim • To understand the principles of gyroscopes and the considerations involved in their operation Application • Used when relying on the gyroscopic instruments • AH, DG and T&B Overview • Definitions • Principles • Considerations – Gyroscope Errors / Limitations • Airmanship • Review Revision Definitions Gyroscope • A rotating mass, mounted so that its axis is free to move in one or more directions. Shows characteristics of rigidity and precession Definitions Rigidity • ability of a gyroscope to maintain their alignment in space despite what occurs around them Definitions Precession • the tendency for a force to be displaced 90 further on in the direction of rotation, from where it was applied Principles Rigidity • degree of rigidity depends upon mass of rotor, the rotational speed, and the radius at which the mass is concentrated. So, a large mass concentrated near the rim and rotating at high speeds provides the greatest rigidity. Principles • Driving the Gyro – Electrical – Vacuum Principles Types of Gyroscopes • Tied Gyro – is tied to a desired position by an external force. • Earth Gyro – is free to move in two planes. Controlled by gravity and is referenced to the centre of the Earth. • Rate Gyro – measures a rate of change. Principles Power Sources • Air Driven – air directed on buckets to drive rotor. System is unserviceable when vacuum pump fails, which is indicated on the suction gauge. • Electrically Driven – rotates gyro at higher speed (greater rigidity). Unserviceable with electrical failure, indicated by annunciation. Principles • Artificial Horizon Principles • Directional Gyro Principles • Turn Co-ordinator Considerations Apparent Wander • due to Earth’s rotation. As aircraft moves over ground, the line in space from the aircraft to North will steadily change. Predicted using 15s in Latitude Real Wander • due to gyroscopic imperfections (lack of rigidity). Can not be predicted. Failures • vacuum failure = AH and DG unserviceable • electrical failure = T&B unserviceable Airmanship • Align gyroscopes prior to use • Know suction limitations • Taxi checks • Be aware of failures Review作者: 猪也能飞 时间: 2013-10-28 19:17:12