5 Piston Engines Ignition – LMS

Results

📄 Notes ⚡ Cheat Sheet

Q1. If an engine fails to stop with the magneto switch in OFF position, the cause may be:

excessive carbon formation in cylinder head

switch wire grounded

fouled spark plugs

defective condenser

Q2. An impulse magneto coupling

gives a retarded spark at starting

reduces magneto speed during engine warm-up

advances ignition timing and gives a hotter spark at starting

gives an automatic spark increase during high speed operation

Q3. An aircraft magneto is switched off by:1. grounding the primary circuit 2. opening the primary circuit 3. opening the secondary circuit 4. grounding the secondary circuit. The combination that regroups all of the correct statements is:

2, 3

2, 4

1, 4

1, 3

Q4. The purpose of a distributor in an ignition system is to distribute:

secondary current to the sparking plugs

secondary current to the condenser

primary current to the sparking plugs

primary current to the condenser

Q5. Under normal running conditions a magneto draws primary current:

from a self-contained electro-magnetic induction system

from the aircraft batteries via an inverter

from the booster coil

directly from the aircraft batteries

Q6. Once the engine has started, ignition systems of piston engines are:

dependent on the DC-Generator

independent of the electrical system of the aircraft

dependent on the battery

dependent on the AC-Generator

Q7. If, when the magneto selector switch is set to the OFF position, a piston engine continues to run normally, the most probable cause is that:

A wire from the magneto is in contact with a metallic part of the engine

There is a carbon deposit on the spark plugs electrodes

There are local hot points in the engine (probably due to overheating of the cylinder heads)

On a magneto, the grounding wire is broken

Q8. What is the best method to stop a running engine if the magneto switch ground wire becomes disconnected?

Feather the propeller

No special method is required, if the wire becomes disconnected the engine will stop

Shut off fuel

Lean out mixture until engine backfires and stops

Q9. When the magneto selector switch is set to ” OFF” position, the piston engine continues to run normallyThe most probable cause of this failure is that:

A wire from the magneto is in contact with a metallic part of the engine

The grounding wire is broken on a magneto

There are local hot points in the engine (probably due to overheating of the cylinder heads)

There is a carbon deposit on the spark plugs electrodes

Q10. Spark plug fouling is more likely to happen if:

power is increased too abruptly

the aircraft cruises at low speed with the correct mixture

the aircraft descends continuously at idle power

the engine runs at maximum continuous power for too long

Q11. The very rapid magnetic field changes (flux changes) in the primary coil of a magneto are accomplished by the:

contact breaker points closing

contact breaker points opening

rotor turning past the position of maximum flux in the armature

distributor arm aligning with one of the high voltage segments

Q12. Dual ignition provides a factor of reliability and:

provides more voltage

improves combustion efficiency

saves wear caused by using one magneto constantly

aids in starting

Q13. If the ground wire between the magnetos and the ignition switch becomes disconnected the most noticeable result will be that:

the power developed by the engine will be greatly reduced

a still operating engine will run down

the engine cannot be started with the ignition switch in the "ON" position

the engine cannot be shut down by turning the ignition switch to the "OFF" position

Q14. An aircraft magneto is switched off by

grounding the primary circuit

grounding the secondary circuit

opening the secondary circuit

opening the primary circuit

Q15. If the ground wire between the magneto and the ignition switch becomes disconnected, the most noticeable result will be that the engine

cannot be started with the switch in the ON position

will not operate at the right magneto

will not operate at the left magneto

cannot be shut down by turning the switch to the OFF position

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