Page 747 - PPL-engelsk 2025
P. 747
Aircraft general knowledge
8.9.7.1 Function of the ignition system
A powerful permanent magnet is rotated, and high voltage is induced, there are
two independent magnets, each supplying its own set of spark plugs.
When the contact opens, the primary voltage is interrupted, the field lines
collapse and thereby induce a high voltage (20,000 volts) in the secondary
winding, which is fed to the spark plugs via a power distributor.
Both ignition systems are checked before take-off.
The magnet system works best when the engine is running at a speed of more
than 800 rpm.
The ignition system is independent of the aircraft's electrical system.
8.9.7.2 The principle of the ignition system
Here you see the principle of the ignition system. Only one magnet is shown.
The rotating magnet is driven by the engine via gears.
Flyveteori PPL(A)(UL)/LAPL Henning Andersen, Midtjysk Flyveskole© 2025 747
