What happens to the turbine in the pneumatic starter when it is activated?

When the pneumatic starter is activated, the turbine is driven by compressed air. This causes the turbine to turn, which then engages the reduction gears connected to it. The purpose of this mechanism is to translate the high rotational speed of the turbine into a suitable speed for starting the engine. The reduction gears help to control the speed and torque, allowing the starter to effectively crank the engine until it reaches a self-sustaining speed. This process is crucial in ensuring the engine starts properly and efficiently, making the engagement of the reduction gears a key part of the turbine's operation in the pneumatic starter system.