The Direct Reading Compass (DRC) - Ch 11+ 12

Question 1

Fluid Filled Case

Answer 1

The fluid is an oiley substance which damps the motion of the compass card

Provides a periodicity and helps sensitivity

Question 2

Ideal Characteristics

Answer 2

Horizontality: Pendular suspension - reduce effect of dip

Sensitivity: Longer/Stronger magnet = increased sensitivity

Aperiodicity: Smoothing out effect - oiley liquid

Question 3

Acceleration Error

Answer 3

0 Acceleration error accelerating N/S
Max error moving E/W
Magnetic EQ, Error = 0
Max error at the poles

Acceleration error moves needle towards near pole
Deceleration error moves needle towards EQ

Question 4

Turning Error

Answer 4

Max error through N/S
Min error through E/W

The errors are opposite to acceleration

NUNOS

Question 5

NUNOS

Answer 5

N. H. Undershoot North, Overshoot South
20/30 degrees normally

S.H. Opposite to NUNOS

Question 6

Liquid Swirl

Answer 6

Liquid Keeps going when you stop turning

Undershooting: Liquid swirl increases turning effect

Overshooting: Liquid swirl decreases turning effect