Magnetos
What likely effect would a cracked distributor rotor have on a magneto?
Ground the secondary circuit through the crack.
If an aircraft ignition switch is turned off and the engine continues to run normally, the trouble is probably caused by
an open ground lead in the magneto.
A spark plug's heat range is the result of
its ability to transfer heat from the firing end of the spark plug to the cylinder head.
What is the electrical location of the primary capacitor in a high-tension magneto?
In parallel with the breaker points.
Ignition check during engine runup indicates excessive RPM drop during operation on the right magneto. The major portion of the RPM loss occurs rapidly after switching to the right magneto position (fast drop). The most likely cause is
incorrect ignition timing on both magnetos.
What would be the result if a magneto breaker point mainspring did not have sufficient tension?
The points will float or bounce.
When the ignition switch of a single (reciprocating) engine aircraft is turned to the OFF position,
the primary circuits of both magnetos are grounded
Defective spark plugs will cause the engine to run rough
at all speeds.
The amount of voltage generated in any magneto secondary coil is determined by the number of windings and by the
rate of collapse of the magnetic field around the primary coil.
Ignition check during engine runup indicates a slow drop in RPM. This is usually caused by
incorrect ignition timing or valve adjustment.
Magneto pole shoes are generally made of
laminations of high-grade soft iron.
In a high-tension ignition system, the current in the magneto secondary winding is
induced when the primary circuit is interrupted.
If a spark plug lead becomes grounded, the
magneto will not be affected.
How many secondary coils are required in a low-tension ignition system on an 18-cylinder engine?
36
When a magneto is operating, what is the probable cause for a shift in internal timing?
The cam follower wear and/or the breaker points wear.
When internally timing a magneto, the breaker points begin to open when the rotating magnet is
a few degrees past the neutral position.
Why are high-tension ignition cables frequently routed from the distributors to the spark plugs in flexible metallic conduits?
To reduce the effect of the high-frequency electromagnetic waves emanated during operation.
If it is found that a shielded ignition system does not adequately reduce ignition noise, it may be necessary to install
a filter between the magneto and magneto switch.
The purpose of a safety gap in a magneto is to
protect the high-voltage winding from damage.
The purpose of staggered ignition is to compensate for
diluted fuel/air mixture around exhaust valve.
The magnetic circuit of a magneto consists of a permanent multi-pole rotating magnet. The core is made of
soft iron.
In a high-tension ignition system, a primary capacitor of too low a capacity will cause
the breaker contacts to burn.
When removing a shielded spark plug, which of the following is most likely to be damaged?
Core insulator.
As an aircraft engine's speed is increased, the voltage induced in the primary coil of the magneto
increases.
Alignment of the marks provided for internal timing of a magneto indicates that the
magneto is in E-gap position.