Starting an airplane engine seems like a pretty easy task. Simply flip on the power with the master switch and turn the key to start. Of course, what actually happens between when that key turns to “Start” (or the button is depressed for push- button systems) and when the engine starts developing its own power involves a number of steps and interplays that are quite complex.
The starter does most of the hard work. When the key is turned to the Start position, a solenoid closes, which allows a high amount of amperage to go to the starter motor. The motor then goes to work converting electrical energy to mechanical energy. In most systems a series of gears turn, eventually pushing out a small shaft with a number of teeth on the end that rotate. Those teeth grab on the flywheel or ring gear behind the propeller, turning it, which turns the crankshaft, which starts the combstion process. Even if the pilot doesn’t manually disengage the starter, it will automatically do so at a certain rotation speed. Other starters are mounted on the back of the engine, but that's less common in training airplanes.
