III.H.K8 Flashcards
- The magnetic circuit of a magneto consists of a permanent multi pole coating magnet. The core is made of?
Soft iron.
- How is the strength of a magneto magnet checked?
Hold the points open and check the output of the primary coil with an AC ammeter while operating the magneto at a specified speed.
- The E gap angle is usually defined as the number of degrees between the neutral position of the rotating magnet and the position?
Where the contact points open.
- The greatest density of flux lines in the magnetic circuit of a rotating magnet type magneto occurs when the magnet is in what position?
Full alignment with the field shoe faces.
- Magneto breaker point opening relative to the position of the rotating magnet and distributor rotor internal timing can be set most accurately?
During assembly of the magneto before install on the engine.
- What will be the result of increasing the gap of the breaker points in a magneto?
Advance the spark and decrease its intensity.
- What is the purpose of a safety gap in some magnetos?
To discharge the secondary coil’s voltage if an open occurs in the secondary circuit.
- When timing a magneto internally, the alignment of the timing marks indicates that the?
Magnets are in the E gap position.
- When internally timing a magneto, the breaker points begin to open when the rotating magnet is?
A few degrees past the neutral position.
8512-2. Magneto timing drift is caused by erosion of the breaker points and?
Wear of the cam followers.
- What is the electrical location of the primary capacitor in a high tension magneto?
In parallel with the breaker points.
- In a high tension ignition system, the current in the magneto secondary winding is?
Induced when the primary circuit is interrupted.
- What is the radial location of the 2 north poles of a 4 pole rotating magnet in a high tension magneto?
180 degrees apart.
- Magneto pole shoes are generally made of?
Laminations of high grade soft iron.
- What components make up the magnetic system of a magneto?
Rotating magnet, the pole shoes, the pole shoe extensions, and the coil core.
- When will the voltage in the secondary winding of a magneto, installed on a normally operating engine, be at its highest value?
Just prior to spark plug firing.
- As an aircraft engine’s speed is increased, the voltage induced in the primary coil of the magneto?
Increases.
- When internally timing a magneto, the breaker points begin to open when?
The magnet poles are a few degrees beyond the neutral position.
- The purpose of a safety gap in a magneto is to?
Protect the high voltage winding from damage.
- A defective primary capacitor in a magneto is indicated by?
Burned and pitted breaker points.
- What is the purpose of using an impulse coupling with a magneto?
To produce a momentary high rotational speed of the magneto.
- Aircraft magneto housings are usually ventilated in order to?
Provide cooling and remove corrosive gases produced by normal arcing.
- Failure of an engine to cease firing after turning the magneto switch off is an indication of?
An open P lead to ground.
- Alignment of the marks provided for internal timing of a magneto indicates that the?
Magneto is in E gap position.
- When using a timing light to time a magneto to an aircraft engine, the magneto switch should be placed in the?
Both position.
- 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.
- Magneto breaker points must be timed to open when the?
Greatest magnetic field stress exists in the magnetic circuit.
- A certain 9 cylinder radial engine used a noncompensated single unit, dual type magneto with a 4 pole rotating magnet and separately mounted distributors. Which of the following will have the lowest RPM at any given engine speed?
Distributors.
- What likely effect would a cracked distributor rotor have on a magneto?
Ground the secondary circuit through the crack.
- 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.
- What should be used to clean grease or carbon tracks from capacitors or coils that are used in magnetos?
Acetone.
- Which of the following statements moat accurately describes spark plug heat range?
A cold plug is designed so that the insulator tip is reasonably short to hasten the rate of heat transfer from the tip through the spark plug shell to the cylinder head.
- In order to turn a magneto off, the primary circuit must be?
Grounded.
- When performing a magneto ground check on an engine, correct operation is indicated by?
A slight drop in RPM.
- Ignition check during engine run up 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. The most likely cause is?
Faulty or fouled spark plugs.
- If new breaker points are installed in a magneto on an engine, it will be necessary to time the?
Magneto internally and the magneto to the engjne.
- When installing a magneto on an engine, the?
Piston in the cylinder 1 must be a prescribed number of degrees before TDC on compression stroke.
- If the ground wire of a magneto is disconnected at the ignition switch, the result will be the?
Engine will not stop running when the ignition switch is turned off.
- Advantages of dual ignition in aircraft engines are a more complete and quick combustion of the fuel, provides a backup magneto system, and?
Increasing the output power of the engine.
- Which of the following are distinct circuits of a high tension magneto?
Magnetic, primary, and secondary.
- What component of a dual magneto is shared by both ignition systems?
Rotating magnet.
- What would be the result if a magneto breaker point mainspring didn’t have sufficient tension?
The points will float or bounce.
- The secondary coil of a magneto is grounded through the?
Primary coil.
- In the aircraft magneto system, if the P lead is disconnected, the magneto will be?
On regardless of ignition switch position.
