Chapter 6 - Gyroscopic Principles Flashcards
a gyro with two gimbals is said to have…
Two degrees of freedom
What are the two properties of a gyroscope?
Rigidity (gyroscopic inertia)
Precession
What is Rigidity of a gyroscope?
the ability of a gyro to stay fixed in space
property of a gyroscope which resists any force tending to change the plane of rotation of its rotor.
Spin axis tends to maintain a fixed direction in space.
Rigidity is dependent on three factors which are?
the mass of the rotor
The speed of the rotation (RPM) and
The distance of the mass from the centre of the rotor (radius)
What is rigidity proportional to?
Rotors moment of inertia and its angular velocity
What is precession?
the change of direction of the plane of rotation of the rotor caused by an applied force
Transfer the applied force to the gyro rotor
Move 90° in the direction of rotor rotation and this is the point where the applied force acts
What factors affect precession? (3 things)
- Magnitude and direction of the applied force
- Moment of Inertia
- Angular velocity of the rotor
What is precession proportional to?
Force/Rigidity
Indirectly proportional to the rigidity
What is wander? and how many types of wander?
‘wander’ is used to describe any movement (real or apparent) of the gyroscopes spin axis away from a chosen datum, and can be split into 3 types:
What are the three types of wander?
Real, Apparent and Transport
What 2 directions does wander take place?
Topple and drift
What is real wander?
Movement as a result of applied forces such as friction in the gimbal bearings.
What is apparent wander?
A gyro will appear to wander when the direction of its spin axis is compared with a datum which is not, itself, a fixed direction in space. gyro will do its job and maintain its orientation. However, as the aircraft moves around a spherical surface, to an observer, the gyro will appear to wander.
Due to earths rotation
What is transport wander?
A gyro will maintain its original orientation with the north direction as was. Initially aligned with north, it will appear to wander if it travels in an east-west direction. This is due to the convergence of the meridians.
What is topple?
Any movement of the gyro axis in the vertical plane is called topple (or tilt)
