Week 4: Gyroscopic Basics Flashcards
Why do we use gyros?
For stability
When do we use gyro instruments?
When visibility was poor
Which instruments rely on a gyro?
Turn Coord
Directional Gyro
ADI
Gyro stabilized compass
When will a spinning object exhibit gyroscopic properties?
When it reaches the correct speed
What are the 2 important design considerations for a gyro?
Great weight, small size (high density)
high speed rotation with low friction
What makes the gyro have less friction?
Bearings
The heavier the gyro means what for the speed?
Slower speed needed
What are the 2 properties of a gyro?
Precession and Rigidity
What is Rigidity?
When a gyro rotates at high speed, it will remain rigid in the plane it is spinning
What is Precession?
A force acted upon a gyro will be felt 90degrees after the point of application
When do you cage the gyro?
Before spinning up
What are the 2 things that create rigidity?
Mass and speed (increase=increase rigidity)
A gyro has what kind of momentum?
Angular momentum
What are the pivot points that allow the gyro to rotate about its axes?
Gimbals
Does the gyro or the case around it move?
Case around it
The Degrees of Freedom classification disregards what?
The rotors spin axis/plane
What is the term used to indicate the number of directions in which the rotor is free to move?
Degrees of Freedom
1 gimbal is equal to how many degrees of freedom?
1 degree of freedom
What type of gyro uses 1DOF and 1 GImbal
Rate gyros
If spin axis of gyro is parallel to direction of travel what can we measure?
Pitch
What are the 2 types of mountings for a gyro?
Free (Universal)
Restricted (Semi-rigid)
Free mounted are used on which gyros?
Direction and Attitude/vertical gyro
When do we use restricted mounting?
where one of the planes of freedom are held in a fixed relation to base
What do restricted mounting gyros have for temporary displacement?
Spring type mechanism
Where do we use restricted mounting?
For applications where movement is compared to time
Restricted mounting is also know as?
Rate gyro
Which gyro has a spin axis PERPENDICULAR to the earths surface and what instrument does it use?
Vertical Gyro
ADI
Which gyro has a spin axis PARALLEL to the earths surface and what instrument does it use?
Horizontal Gyro
Directional
What is the tilting force that causes a gyro to precess?
Torque
The farther away from the CofG the _______ torque you have to apply
Less
If you want to turn, a turn rate gyro back to level what do you do?
Apply force on Tilt axis which will cause a turn
What is wander?
Any movement of the spin axis away from the fixed direction
gyro wander in the earths horizontal plane is called?
Drift (want N point E)
What is topple?
gyro wander in Vertical plane (want E points S)
What is real wander caused by?
Bearing friction
Imbalance
Inertia of gimbals
What is apparent wander and what is it caused by?
Appears to wander, caused by obverses orientation
What do we use torqueing motors for?
Slowing down gimbal inertia
