POWERPLANT SYSTEM

POWERPLANT SYSTEM

TOPICS

 Engine Ignition and Electrical Systems

 Lubrication and Cooling Systems

 Aircraft Fuel System

 Engine Fire Protection Systems
 Magneto-Ignition System Operating Principles
Engine Ignition and Electrical Systems
 The magneto, a special type of engine-
 The basic requirements for
driven alternate current (AC) generator,
reciprocating engine ignition systems
uses a permanent magnet as a source
are similar, regardless of the type of
of energy.
engine. All ignition systems must deliver
 By the use of a permanent magnet
a high-tension spark across the
(basic magnetic field), coil of wire
electrodes of each spark plug in each
(concentrated lengths of conductor),
cylinder of the engine in the correct
and relative movement of the magnetic
firing order.
field, current is generated in the wire.
 Ignition systems
 This can be divided into two MAGNETO PARTS
classifications: magneto-ignition
systems or electronic Full Authority
Digital Engine Control (FADEC) systems
for reciprocating engines.
 Ignition systems can also be
subclassified as either single or dual
magneto-ignition systems


MAGNETO

 Aircraft magneto-ignition systems can
be classified as either high-tension or
low-tension.
 The low-tension magneto system,
covered in a later section of this
chapter, generates a low-voltage that is
distributed to a transformer coil near
each spark plug. This system eliminates
some problems inherent in the high-
tension system that was containing the
high-voltage until it passed through the
spark plug.
 Low tension- create several problem in
the Engine. Most used is high tension.
(hard starting if low tension).
 This is direct with the timing gear.
 The one who supply electricity for
Sparkplugs.

,  Engine Startaing Systems
 Most aircraft engines, reciprocating or
Ignition Harness
turbine, require help during the starting
 The ignition lead directs the electrical energy process. Hence, this device is termed
from the magneto to the spark plug. The the starter. A starter is an
ignition harness contains an insulated wire for electromechanical mechanism capable
each cylinder that the magneto serves in the of developing large amounts of
engine. mechanical energy that can be applied
 One end of each wire is connected to the to an engine, causing it to rotate.
magneto distributor block and the other end is  STARTER>ENGINE>STARTER GEAR> FLY
connected to the proper spark plug WHEEL

Lubrication and Cooling Systems
 The primary purpose of a lubricant is to
reduce friction between moving parts.
 Because liquid lubricants or oils can be
circulated readily, they are used
universally in aircraft engines.
 Air cooled Engine Coolant/ Liquid
Cooled Engine Coolant
 Extending the life span of an Engine.

 Functions of Engine Oil
 In addition to reducing friction, the Oil
Spark Plugs
Film Acts as a cushion between metal
 The function of the spark plug in an ignition parts.
system is to conduct a short impulse of high-  This cushioning effect is particularly
voltage current through the wall of the important for such parts as
combustion chamber reciprocating engine crankshafts and
connecting rods, which are subject to
shock loading.

 Requirements and Characteristics of Reciprocating
Engine Lubricants
 There are several important properties
that satisfactory reciprocating engine oil
must possess, its Viscosity is most
important in engine operation.
 The resistance of an oil to flow is known
as its Viscosity. Oil that flows slowly is
viscous or has a high viscosity; if it
flows freely, it has a low viscosity.

Viscosity Index

 The viscosity index is a number that
indicates the effect of temperature
changes on the viscosity of the oil.