The Magnetic Compass

Question 1

An aperiodic compass is one whose needle takes?

Answer 1

Up its direction with one movement, without oscillation.

Question 2

Compass liquid, methyl, kerosene or a silicon fluid, is used to?

Answer 2

Achieve aperiodicity, which is to reduce oscillation.

And to lubricate the pivot

Question 3

Th degree of oscillation also depends on the?

Answer 3

Moment of inertia, which in turn depends on the size of the magnets.

Question 4

The magnetic compass is free to tilt?

Answer 4

+/- 20 degrees from the horizontal

Question 5

There is a delay in the compass card stopping after a turn, this caused by and called?

Answer 5

Caused by the liquid within the compass to turn with the aircraft, called liquid swirl.

Question 6

Improving magnet strength of the magnetic compass, is achieved by?

Answer 6

Adding more magnets, the magnetic compass contains two or four magnets.

Question 7

Magnetic compass acceleration and deceleration error increase with, and is zero at the?

Answer 7

Increases with latitude, and is zero at the magnetic equator

Question 8

Accelerate and decelerate is zero on what cardinal headings?

Answer 8

North and South

Question 9

How to remember accelerating and decelerating error?

Answer 9

Just sketch the compass pointer with a forward PIVOT point towards the northern side, resulting in a rearward CG, and use common sense on what the effects of inertia will be.( For the southern hemisphere, reverse if northern hemisphere)

Question 10

In the southern hemisphere, how to remember turning error?

Answer 10

ONUS

Question 11

In the northern hemisphere, how to remember turning error?

Answer 11

UNOS

Question 12

At the magnetic equator acceleration and deceleration errors are?

Answer 12

Zero

Question 13

Acceleration and deceleration error increase with?

Answer 13

Increasing latitude

Question 14

In the Northern hemisphere, why undershoot north?

Answer 14

Because the compass is “under” indicating

Question 15

In the Northern hemisphere, why overshoot south?

Answer 15

Because the compass is “over” indicating

Question 16

In the Southern hemisphere, why overshoot north?

Answer 16

Because the compass is “over” indicating

Question 17

In the Southern hemisphere, why undershoot south?

Answer 17

Because the compass is “under” indicating

Question 18

Acceleration / Deceleration is maximum -

And zero -

Answer 18

On East / west headings

On North / South headings

Question 19

You accelerate to the west in the northern hemisphere, what is the apparent heading change?

Answer 19

The assembly turns anti-clockwise, resulting in an apparent increase in heading to the north, the compass over-reads.

Question 20

You accelerate to the east in the northern hemisphere, what is the apparent heading change?

Answer 20

The assembly turns clockwise, resulting in an apparent decrease in heading to the north, the compass under-reads.

Question 21

Explain acceleration / deceleration error:

Answer 21

Moving away from the magnetic equator, the compass needle wants to point down towards the north pole(magnetic dip). As a result, the pivot point moves forward towards the north pole(south pole in the southern hemisphere) resulting in a rearward CG.

As the aircraft accelerates or decelerates on East / West headings inertia will act on this CG moving the compass assembly causing an error.

Accelerate West in the northern hemisphere: Assembly will rotate anti-clockwise, causing an apparent increase in heading towards the north pole.

Accelerate East in the northern hemisphere: Assembly will rotate clockwise, causing an apparent decrease in heading towards the north pole.

the rest will be long to type, just use your knowledge on the pivot and CG change.