Gyro Theory

Question 1

Factors effecting gyro rigidity

Answer 1

Mass

Speed of rotation

Distribution of mass - furthest from the axis of rotation the more rigid

Question 2

Gimbals

Answer 2

Allow the gyro to take up and hold its own orientation when the gimbals are moved around

Question 3

Degree of freedom

Answer 3

Each axis on the gimbal excluding the spin axis

E.g 1 gimbal is added = introduced 1 additional rotation axis = 1 degree of freedom

Question 4

If 2 gimbals are used

Answer 4

2 degrees of freedom introduced

Gyro can be moved around 3 planes without disturbing the gyro

Question 5

2 planes of rotation

Answer 5

1 gimbal

1 degree of freedom

Question 6

3 planes of rotation

Answer 6

2 gimbals

2 degrees of freedom

Question 7

Gyro instruments

Answer 7

Direction indicator
Attitude indicator
Turn indicator

Question 8

Gimbal lock

Answer 8

2 or more gimbals become aligned with each other which reduces the planes of rotation and the degrees of freedom

Common during acrobatics

Question 9

Categories of gyro scope wander

Answer 9

Real

Apparent

Question 10

Topple

Answer 10

The motion of axis in the vertical plane

Only occurs if the spinning axis is completely vertical

Dealt with by erection systems

Question 11

Drift

Answer 11

Movement in the horizontal plane

Concern in navigation

Question 12

Earths rotation speed at the poles

Answer 12

The earth rotates eastwards at 600kts and 15.04 degrees/hr

Question 13

Vertical gyro at the equator

Answer 13

The observer will witness a topple by 90degrees every 6 hrs by either ER or TW

Max topple, no drift

Vertical will become horizontal

Question 14

TW

Answer 14

Transport wander, to do with the movement of the gyro when the a/c travels across the earths surface

Question 15

What will happen to the gyro when flying due north up a meridian from the equator

Answer 15

To an observer a vertical gyro will appear to topple backwards and become horizontal at the pole

It will also progressively drift

Question 16

At the poles

Answer 16

Vertical gyros appear not to drift or topple

Horizontal gyros appear to drift

Question 17

At the equator

Answer 17

Vertical gyros appear to topple

An east aligned horizontal gyro appears to topple backwards to the vertical

A north aligned horizontal gyro will neither topple or drift if it remains on the equator

Question 18

Real wander

Answer 18

Happens in all gyros

Caused by bearing friction

Question 19

The Latitude nut

Answer 19

Used to compensate for the ER at the a/c’s operational latitude

Small nut is adjusted which inputs a real wander effect to correct its position