Remote Indicating Compasses

Question 1

Basic principle of how the remote indicating compass functions?

Answer 1

Since magnetic flux passes through the length of a ferrous metal bar when parallel to the flux, if the angle of the bar is changed magnetic flux change can be measured (Horizontal component) leading to a magnetic heading indication.

Question 2

Flux heading ambiguity can be resolved by using?

Answer 2

3 flux valves positioned 120 degrees apart

Question 3

The detector unit contains the?

Answer 3

Sperry Flux Valve

Question 4

Can the direct indicating compass relay information to other equipment?

Answer 4

No

Question 5

The Remote Indicating Compass usually replaces the?

Answer 5

DI

Question 6

Does the Remote Indicating Compass suffer from turn and accelerate error?

Answer 6

Yes, but it’s suppressed and not shown by the indicator.

Question 7

Can The Remote Indicating Compass heading be relayed to other equipment?

Answer 7

Yes

Question 8

When operating in very high latitudes where the magnetic compass becomes unreliable the Remote Indicating Compass can be?

Answer 8

Used as a directional gyro at the flick of a switch

Question 9

Sperry Compass principle of operation?

Answer 9

The three induced voltages from the flux valve(Detector Unit) , which it receives by sensing the earths magnetic field, are fed to their three respective stator coils in the
signal selsyn of the gyro unit. The stators are energised and produce a magnetic feld. A rotor coil mounted on a mechanically driven
shaft will sense the direction of the magnetic field produced by the stators.
The compass pointer or compass card is on the same shaft as the rotor of the signal selsyn and is
aligned during manufacture so that when the rotor coil is at right angles to the magnetic field
produced by the stators, the magnetic heading of the aircraft is correctly indicated.

Question 10

If the rotor of the signal selsyn is not at the null position( Gyro and compass not synchronised)?

Answer 10

An AC current is induced. This error signal is passed to the precession amplifier where it is amplified, rectified and phase detected and passed in DC form the precession circuit of the gyro.

1. The error signal is fed from the precession amplifier via the annunciator to the precession coil of the gyro unit.
2. The precession coil is energised
3. The precession coil magnetic field interacts with the magnetic fields produced by the two horn permanent magnets, repulsion from one, attraction from the other. This is a precessional force F1
   which acts at 90 degrees in the direction of gyro spin as force F2 and the gyro and the horizontal bevel gear on which the gyro is mounted precess anti- clockwise.
4. The horizontal bevel gear drives the vertical bevel gear, which rotates the shaft, the signal selsyn rotor and the compass card.
5. When the rotor reaches the null position, the error signal disappears and the circuit to the precession coil ceases, F1 and F2 disappear, the gyro and the compass are synchronised.

Question 11

The Annunciator indicates whether the?

Answer 11

Compass is synchronised or not

Question 12

The Sperry CL 1 is erected by?

Answer 12

Two torque motors