How Magneto Works | Simply explained for student pilots.

Summary

This video explains the operation of magnetos in piston engine airplanes, detailing how they generate high voltage to ignite the fuel-air mixture in the engine. It describes the process of electrical current generation through the movement of magnets and coils, and how a breaker point and capacitor work together to produce a strong spark. The video highlights the importance of the distributor in routing the voltage to spark plugs and notes that airplanes often have dual magnetos for reliability. Overall, it emphasizes the simplicity and effectiveness of this critical component in aviation engines.

Takeaways

• 🔋 Magnetos are self-contained high voltage generators used in piston engine airplanes to provide electrical current to the spark plugs.
• ⚡ The primary function of a magneto is to ignite the fuel and air mixture in the engine at the correct time in the engine cycle.
• 🧲 Electrical current is generated when a magnet moves through a coil of copper wire, creating a magnetic field.
• 💡 The electrical current generated can light up a bulb or create a spark in the spark plug, igniting the fuel and air mixture.
• ⚙️ In a magneto, a strong magnet is driven by the engine through a gear system, rotating inside an iron core.
• 🔄 The magnet rotates at crankshaft speed, inducing electrical current in two coils: primary and secondary.
• 🚫 The primary coil generates insufficient voltage for a spark, but its current creates a magnetic field that is essential for ignition.
• 🔄 The breaker point opens twice per crankshaft revolution, stopping current flow in the primary coil and inducing a voltage spike.
• 🔋 A capacitor is used to prevent arcing at the breaker point, allowing for a quicker collapse of the magnetic field and a stronger voltage spike.
• 🔌 The distributor routes high voltage current from the secondary coil to each spark plug at the correct time in a four-cylinder engine.

Q & A

What is the primary function of a magneto in piston engine airplanes?

The primary function of a magneto is to provide electrical current to the spark plugs, igniting the fuel and air mixture at the correct time in the engine cycle.

How is electrical current generated in a magneto?

Electrical current is generated when a magnet moves through a coil of copper wire, creating a magnetic field that induces an electrical current in the coil.

What components make up a magneto, and how do they work together?

A magneto consists of a strong magnet, an iron core, and two copper wire coils (primary and secondary). The magnet rotates, generating current in the primary coil, which induces a higher voltage in the secondary coil.

Why is the voltage generated in the primary coil insufficient for creating a spark?

The voltage generated in the primary coil is not high enough to create a spark in the spark plug, but it creates a magnetic field that collapses when the current stops, inducing a voltage spike in the secondary coil.

What role does the breaker point play in a magneto?

The breaker point is used to suddenly stop the current in the primary coil, which causes the magnetic field in the core to collapse quickly, leading to a voltage spike that generates a spark.

How does a capacitor improve the function of a magneto?

A capacitor prevents arcing across the breaker points by allowing the current to flow into it when the breaker point opens, enabling a rapid collapse of the magnetic field and a strong voltage spike.

What is the function of the distributor in a magneto system?

The distributor is a rotating switch that routes the high voltage current from the secondary coil to each spark plug at the correct time and in the proper firing order.

What are some potential failures that can occur in a magneto?

Potential failures include fracturing of the plastic gears or failure of the capacitor, which can prevent the magneto from generating a spark.

Why do airplanes typically have two magnetos?

Airplanes typically have two magnetos for backup and improved performance, ensuring that if one magneto fails, the other can still provide the necessary spark for ignition.

How does the rotation speed of the magnet relate to the crankshaft speed in a four-cylinder engine?

In a four-cylinder engine, the magnet rotates at crankshaft speed, which is essential for generating the electrical current needed for ignition at the right moment in the engine cycle.