This color educational film is about an aircraft magneto which is an engine driven electrical generator that uses permanent magnets and coils to produce high voltage to fire the aircraft spark plugs. Aircraft magnetos are used in piston aircraft engines and known for their simplicity and reliability. This is circa the 1940s.
Opening titles: Scintilla Magneto Division presents The Aircraft Magneto Part 1: Theory Of Operation Of The Four Pole Magneto (:06-:32). Various machine pieces and screws move around and piece themselves together (:33-1:16). Different types of aircraft magnetos. A man places an aircraft magneto down. Magnets and wires are then placed down. A steel magnet is used and attracts iron. Each magnet has poles, north and south, opposite poles attract. Lines of magnetic flux are explained. Iron nail is stuck to a magnet (1:17-3:55). Iron nails are known as temporary magnets. Lines of flux. Magnet and wire (3:56-5:27). Wire and a magnet are near one another and explained with how currents flow. Lines of flux in the magnet and one line of wire. Diagram explains current flow (5:28-7:20). Using a stronger magnet is explained along with more coils of wire as flux linkage increases. Wire carries a current in an experiment (7:21-8:30). In the experiment, when the wire is cut, field around the wire disappears. Magnetic field and flux linkage is shown and explained (8:31-10:27). Lenz’s Law is explained with a title card, a law stating that the direction of an induced current is always such as to oppose the change in the circuit or the magnetic field that produces it. A diagram shows how this works and explains it (10:28-12:15). Soft iron core, two magnets that can be rotated, iron shoes, a diagram shows how these items together will move the flux. Full register position of the magnet (12:16-13:28). Diagram shows magnet turning. A coil of copper wire is the primary coil. Static flux. Primary flux and static flux with the resultant flux (13:29-15:26). Primary wire is cut causing the flux to stop; diagram shows this (15:27-16:21). How a magneto can work is shown in a diagram and explained. E-gap explained (16:22-18:10). Inside the magneto as the flux goes is shown via a diagram. Flux surges (18:11-19:42). Inside the magneto diagram. Break in a circuit causes a flux change.The current and the gap are shown and explained (19:43-21:11). A condenser is connected. The condenser is shown on a diagram and explained. Magneto is ready for use (21:12-22:14). Aircraft ignition system with two magnetos, spark plugs, and switch. How voltage works is explained in a diagram (22:15-23:49). Aircraft magneto as it is assembled. Rotating magnet, crankshaft. Soft iron. Thin sheets of soft iron. Pole shoes and pole extensions. Primary condenser. Nickel foil plates (23:50-25:39). Coil assembly in a magneto is shown and explained with real parts. Breaker assembly, spring and breaker points (25:40-27:00). Distributor block. Diagram inside a magneto as current moves towards distributor. Dots are shown to represent a spark. Magneto. Plane takes off from a Carrier. U.S. planes in the sky (27:01-29:46). End credits (29:47-29:55).