Gyroscopic Instruments Flashcards
2 characteristics of gyroscopes
Rigidity and precession
Modifiers of rigidity
Rigidity is gyroscopic inertia
Higher mass
Mass distribution to edges
Higher rotational velocity
Precession
Force applied acts 90° in direction of rotation
Rate of precession
Strength and direction of the force applied
Inversely proportional to mass and distribution of gyroscope and rotational velocity
Gimbals
Keep keep gyroscope stabilised and centered
Rotor power source
Spun by air vacuum or electric motor
Air is Venturi system or vacuum system
Vacuum system powered by battery or alternator
Vacuum pump
Provides 8-10” hg reduced to 4.5-6” hg by pressure relief valve
Gyroscope types
Space gyroscope
Free to move on all planes
Earth gyroscope
Kept on y axis by force of gravity
Type of tied gyro
Tied gyroscope
Gyroscope kept in one plane by exterior force
Rate gyroscope
Free in one plane (not plane of rotation)
Movement in third plane is used to measure precession
Attitude indicator
AI
Uses horizontally spinning gyro
Pitch moves opposite roll moves same
Pendulus unit
Weighted unit base of inner gimbal rotor casing
Maintains true vertical
Uses vanes closing ports to apply precessed force that pushes gyro back to true vertical
AI errors
Pendulosity and erection error
Acceleration and turning error
Pendulosity
CoG of Pendulous unit (inner gimbal casing is below the points of suspension
Turning and accelerating causes unit to swing and precess and produce incorrect reading
Erection error
Accelerating and turning causes vanes to swing and create precessed force
Acceleration
Climbing right turn
Decelerating
Descend left
Driven AI limits
+/- 55 degrees of pitch and 90° roll
If exceeded gyro will topple
Cage system locks gimbal allows for reset
