The Vacuum System and Gyroscopic Instruments Flashcards
How are most vaaccum systems powered?
Engine-driven suction pump
How is the suction pump powered?
By the engine
The suction pump powers what system?
Vacuum system
What does a suction pump do?
Creates a vacuum in gyroscopic instruments
How does a suction pump create a vacuum?
Evacuates the cases of instruments
What creates a vacuum in gyros?
Suction pumps
What is the first component in a vacuum system?
Air filter
Where is the suction pump located in the vacuum system?
At the end
What is located at the end of a vacuum system?
Suction pump
What item immediately precedes the suction pump?
Vacuum relief valve
What is the typical required suction?
3 to 5 inches of mercury
What is the most common cause of a low suction gauge reading?
Blocked air filter
What is the most common cause of a zero suction gauge reading??
Suction pump failure
How are excessive vacuum pressures prevented?
Vacuum relief valve
How does a venturi tube provide suction?
The low static pressure area in the venturi will cause higher pressure air in the instruments to flow to the tube
An area of low static pressure drawing airflow from instruments describes what system?
Venturi tube vacuum system
What is rigidity in space?
The ability for a rotating mass to maintain the same absolute direction in space
The ability for a rotating mass to maintain the same absolute direction in space describes what?
Rigidity in space
Gyroscopes have what crucial property?
Rigidiy in space
As an aircraft moves ‘around’ a gyro, what happens to the gyro?
It remains stable in space
What 3 factors affect the degree of rigidity in space of a gyroscope?
Mass of the rotor
Speed of rotation
Radius of mass
What do these symptoms affect:
Mass of the rotor
Speed of rotation
Radius of mass
Rigidity in space
What is the most optimal gryoscope in terms of directional rigidity?
Large mass concentrated at the rim rotating at high speed
What is the secondary property of a gyroscope?
Precession
The change in direction of a gyroscope if a force is applied to it is in what manner?
90 degrees further on to the direction of rotation
Precession describes what kind of movement?
90 degrees further on to the direction of rotation
When will a gryo under-read?
If rotation reduces
If a gyro under-reads, what has happened to it?
Its rotation has reduced
Precession’s angle relationship to direction of applied force?
90 degrees
What causes a slow drift in gyros?
Precession
Precession is associated with what instrument phenomenon?
Gyro drift
What risk may be associated with a vacuum pressure pump, as opposed to a vacuum suction pump?
A pressure pump would also pump contaminants such as oil into the gyroscopic instruments
What kind of gyros do the turn indicator/coordinator use?
Rate gyros
Rotation speed gives the gyro what property to resist tilting or turning?
Inertia
What does inertia mean for a spinning gyro?
It can resist tilting or turning
What allows gyros to hold their position while the instruments rotate around it?
Inertia
Precession iis essentially the combination of what two forces?
Perpendicular to direction of force + direction of rotation
What gyro instruments are vacuum powered?
Attitude Indicator and DI
What gyro instruments are electrically powered?
Turn indicator/coordinator
What does the Turn indicator/coordinator NOT show?
Bank angle
What does the Turn indicator/coordinator show?
Rate of turn
What will a turn coordinator show in addition to what a turn indicator shows?
Rate of bank
A turn coordinator’s 30-degrees angled gimbal means it provides reaction to what?
Rate of bank as well as just bank
What returns the gimbal to the central position in a turn indicator?
Spring
What does a spring do in a turn indicator?
Resists gimbal rotation
What happens to a turn indicator when the aircraft stops turning?
Spring tension returns the gyro to its original position
What kind of gyro is used in the attitude indicator?
Earth gyro
An earth gyro is used for what instrument?
Attitude indicator
What spin axis does an earth gyro have?
Vertical
What spin axis does a rate gyro have?
Horizontal
The pivoting components in a gyro are given what term?
Gimbals
What do gimbals do in a gyro?
Pivot
What term is given to the mechanical errors in DIs that will cause it to drift off accurate alignment with magnetic north?
Mechanical drift
Mechanical drift in DIs are caused by what?
Friction
Friction causes what in DIs?
Mechanical drift
What term is given to the error in DIs that cause drift due to the aircraft’s movement through space relative to north?
Apparent drift
