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An Overview of Aircraft Magnetos

In the realm of aviation, the internal combustion engines of piston aircraft rely on a critical component known as a magneto to ensure ignition. This device plays a pivotal role in the ignition system of these aircraft, providing a dependable source of electrical energy to ignite the air-fuel mixtures within engine cylinders. In this article, we will offer insight into the inner workings of aircraft magnetos, exploring their components, functionality, and significance in piston aircraft operations.

The Basics of Magnetos

To comprehend the importance of a magneto in aviation, one must first grasp its general role within the broader context of an internal combustion engine. Aircraft engines, much like their automotive counterparts, require a spark to initiate the combustion process. In a piston aircraft, the magneto fulfills this need, generating the necessary electrical energy for the ignition of fuel-air mixtures.

Components of a Magneto

The typical magneto consists of several key components that work harmoniously to produce the required electrical spark. At its core, it comprises a stator and a magnet rotor, the stator being a stationary coil of wire that surrounds the magnet rotor. This coil generates a magnetic field when current flows through it. Meanwhile, the magnet rotor serves as a rotating magnet.

The Breaker Points

Breaker points are another crucial element within a magneto, these points being situated within the stator. Breaker points are responsible for interrupting the flow of current to the magnet rotor. This interruption creates a sudden collapse of the magnetic field, inducing a high-voltage surge in the coil.

How the Magneto Works

As the aircraft's engine crankshaft rotates during operation, it drives a gear that is connected to the magnet rotor. This rotation induces the magnet rotor to spin within the stator's coil. Simultaneously, the breaker points, which are also linked to the magnet rotor, open and close as the rotor turns.

When the breaker points open, the magnetic field around the coil collapses rapidly. This collapse induces a high-voltage surge in the coil, a phenomenon known as electromagnetic induction. This surge is then sent through high-tension wires to the spark plugs in the engine cylinders, allowing for the fuel-air mixture to be ignited.

The Role of the Magneto Switch

Now, you might be wondering how a pilot controls this critical ignition component during flight. This is where the magneto switch on the aircraft's control panel comes into play. The magneto switch allows the pilot to select between two magneto units, labeled as left and right magnetos. Each unit corresponds to one set of spark plugs, usually arranged in pairs within the engine cylinders for reliability.

Why Two Magnetos?

One might wonder why two magnetos are used when one is sufficient for basic combustion, and the answer is redundancy and safety. Having two separate ignition systems with their own sets of spark plugs ensures that if one system were to fail, the engine would still run, albeit at reduced power. This redundancy is a vital safety feature in aviation, where engine failure can have dire consequences.

Maintenance and Care

Like any other component of an aircraft, magnetos require regular maintenance and inspections to ensure they remain in optimal working condition. Mechanics will often check the breaker points, conduct routine testing, and replace worn-out parts to keep the ignition system reliable. To ensure a proper interval to not let anything slip through the cracks, one should have magnetos inspected based on manufacturer recommendations and/or during scheduled checks.


In summary, aircraft magnetos are a fundamental part of the ignition system in piston aircraft, providing the electrical energy needed for engine combustion. Comprising components such as the stator, magnet rotor, and breaker points, these devices play a critical role in ensuring the reliability and safety of aircraft engines. If you are in the market for top-quality magneto components and aviation products that you can steadily depend on, look no further than Aerospace Domain and our unrivaled selection of items that are ready for purchase at any time.

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