Category: Flight Instruments

Directional Gyro Indicator Introduction to Directional Gyro Indicator DGI provides heading using a tied gyro with two degrees of freedom Spin axis of gyro is maintained in the yawing plane of the aircraft Gyro motor is located in the inner gimbal and readings seen on outer gimbal Outer gimbal can rotate through 360 deg Rotor axis, inner and outer gimbals are at right angles to each other In an air driven DGI, engine driven pump provides air jet to spin the rotor The outer gimbal turns whereas spin axis remains…

Drift and Topple of Gyroscopes Gyroscopic Wander Gyro wander is the departure of the gyro spin axis from its original position Wander is calculated with respect to surface of earth Gyroscopic wander is classified as drift and topple Deviation of spin axis in the horizontal plane is called Gyro drift Gyro topple is the deviation of spin axis in a vertical plane Wander in Horizontal and Vertical Axis Gyro Spin axis of horizontal axis gyros are horizontal to the earth’s surface Horizontal axis gyroscopes can drift as well as topple…

Gyroscopes Gyroscope & Instruments Gyroscopes are used in a variety of flight instruments Directional gyro indicator and Gyro magnetic compass Artificial horizon and Turn & slip indicator Inertial navigation systems and Inertial reference systems Yaw dampers and Auto pilot Stabilization of radar scanners Gyroscopic Theory Gyroscope has a spinning disc called rotor which spins around its spin axis Gyroscopes have two basic properties of rigidity and precession A highly rigid gyroscope will have low rate of precession and vice versa A gyroscope with its spin axis horizontal to earth surface…

Direct Indicating Compass Direct Reading Compass Direct reading or indicating compass is the simplest type of aircraft compass DIC uses horizontal component of magnetic field The maximum permissible deviation on any heading is less than 10 deg Horizontality, Sensitivity and Aperiodicity are required in a good compass Construction of Direct Reading Compass Direct indicating compass consists of a liquid filled compass bowl The magnetic assembly consists of a compass card in a pivoted assembly A lubber line in outer casing provides the reference direction The lubber line is aligned with…

Earth’s Magnetism Magnetism Magnetism is the property of certain materials to create a magnetic force Magnetic force attracts or repels similar materials Ferrous metals like steel, nickel or cobalt can be magnetised Non-ferrous metals like aluminium cannot be magnetised Magnetic Field Magnetic field is the space around magnet where magnetic influence is felt Magnetic lines of force is pattern in a magnetic field Varies with shape and strength of magnet Red end is the north seeking end which points to magnetic north Blue end is south seeking end which points…

Angle of Attack Indicator Angle of Attack Angle of attack is the angle between the wing chord line and the direction of air flow Increase in angle of attack provides increased lift until a certain point Beyond a point drag increases abruptly Can cause aircraft to stall Angle of Attack Indicator Angle of Attack indicator, provides visual indication of angle of attack Used in stall warning system Sensors mounted on the side of front fuselage Types of Angle of Attack Sensors Angle of Attack sensors are of two types Slotted…