Pilot's Handbook of Aeronautical Knowledge
Preface
Acknowledgements
Table of Contents
Chapter 1, Introduction To Flying
Chapter 2, Aircraft Structure
Chapter 3, Principles of Flight
Chapter 4, Aerodynamics of Flight
Chapter 5,
Flight Controls
Chapter 6,
Aircraft Systems
Chapter 7,
Flight Instruments
Chapter 8, Flight Manuals and Other Documents
Chapter 9,
Weight and Balance
Chapter 10, Aircraft Performance
Chapter 11, Weather Theory
Chapter 12,
Aviation Weather Services
Chapter 13,
Airport Operation
Chapter 14,
Airspace
Chapter 15, Navigation
Chapter 16, Aeromedical Factors
Chapter 17, Aeronautical Decision Making
Appendix
Glossary
Index |
Figure 7-27. The soft iron frame of the flux valve accepts the flux
from the Earth's magnetic field each time the current in the center
coil reverses. This flux causes current to flow in the three pickup
coils.
As the current reverses between the peaks, it demagnetizes
the frame so it can accept the flux from the Earth's field As
this flux cuts across the windings in the three coils, it causes
current to .ow in them. These three coils are connected in
such a way that the current .owing in them changes as the
heading of the aircraft changes. [Figure 7-28]
The three coils are connected to three similar but smaller coils
in a synchro inside the instrument case. The synchro rotates
the dial of a radio magnetic indicator (RMI) or a HSI. |
Figure 7-28. The current in each of the three pickup coils changes
with the heading of the aircraft.
Remote Indicating Compass
Remote indicating compasses were developed to compensate
for the errors and limitations of the older type of heading
indicators. The two panel-mounted components of a typical
system are the pictorial navigation indicator and the slaving
control and compensator unit. [Figure 7-29] The pictorial
navigation indicator is commonly referred to as an HSI.
The slaving control and compensator unit has a push button
that provides a means of selecting either the "slaved gyro"
or "free gyro" mode. This unit also has a slaving meter
and two manual heading-drive buttons. The slaving meter
indicates the difference between the displayed heading and
the magnetic heading. A right deflection indicates a clockwise
error of the compass card; a left deflection indicates a
counterclockwise error. Whenever the aircraft is in a turn
and the card rotates, the slaving meter shows a full deflection
to one side or the other. When the system is in "free gyro"
mode, the compass card may be adjusted by depressing the
appropriate heading-drive button.
Figure 7-29. Pictorial navigation indicator (HSI, top), slaving meter
(lower right), and slaving control compensator unit (lower left). |
|