Chap 5: Gyroscopic Instruments

Question 1

factors that affects amount of rigidity in gyroscope

Answer 1

speed & weight of rotor

distance of mass from axis of spin

Question 2

factors that affects the amount of precession in gyroscope

Answer 2

rigidity of gyroscope

strength of applied torque

Question 3

types of gyroscopes and its uses

Answer 3

tied - heading indicator
earth (vertical) - attitude indicator
two-degree freedom (rate) - turn coordinator
three-degree freedom (space)

Question 4

degrees of freedom in a gyroscope

Answer 4

spinning freedom (XX1) - spin axis
tilting freedom (YY1) - axis of tilt
veering freedom (ZZ1) - axis of veer

Question 5

properties of a gyroscope

Answer 5

gyroscopic inertia or rigidity (resist the force tending to change the plane of rotation of rotor)

precession (angular change in direction of the plane of rotation influenced by applied force)

Question 6

factors that affects rate of precession

Answer 6

strength and direction of applied force
moment of inertia & angular velocity of rotor

higher force = higher rate of precession
higher moment of inertia / angular velocity = smaller rate of precession

Question 7

what is real precession

Answer 7

deflection of spin axis caused by external applied forces

Question 8

types of precession and its causes

Answer 8

real precession (external applied force)
apparent precession (earth's rotation)
random precession (caused by unbalanced motor/bearing friction)

Question 9

purpose of turn and slip indicator

Answer 9

indicates:

1) lateral attitude of the aircraft in straight flight
2) rate of turn of aircraft about vertical axis
3) side-slip or skid

Question 10

purpose of gyro horizon

Answer 10

indicates pitch and bank attitude of a/c relative to vertical axis

Question 11

purpose of erection device on air driven gyro horizon

Answer 11

erect the gyroscope, bring spinning axis to vertical and maintain in this attitude as long as there is suction

Question 12

precautions when using fast erection switch

Answer 12

1) switch must not be pressed for more than 15 seconds to prevent overheating of stator coil due to high current
2) switch can only be pressed during straight/level flights or shallow angles

Question 13

purpose of heading indicator

Answer 13

inform the pilot of the aircraft’s direction that they are heading to

Question 14

purpose of erection device for air driven direction indicator

Answer 14

senses misalignment of rotor axis in terms of unequal air reaction

Question 15

what is an artificial horizon

Answer 15

attitude indicator = gyro horizon = artificial horizon

Question 16

gyroscopic property used in the operation of an artificial horizon is

Answer 16

rigidity

Question 17

indication of a turn indicator is based on

Answer 17

gyroscopic precession

Question 18

erection system of the Gyro Horizon maintains the spin axis

Answer 18

vertical to the earth’s horizon

Question 19

power supply of electric erection device

Answer 19

single phase 20 volts 400Hz

Question 20

how to read gyro horizon

Answer 20

if line is under aircraft: Climbing

if line is middle of a/c: banking / straight level flight

if line is above a/c: descending turn / straight descending

Question 21

how to read turn and slip indicator

Answer 21

straight line w left bar: straight with left wing low
line pointing left w left bar: left turn with slip
line point left with right bar: left turn with skid

if same side means slip
opposite side means skid