Final answer:
A free-turbine turboshaft engine is a type of engine used in helicopters and some aircraft. It consists of a gas generator and a power turbine, which can rotate independently of each other. This design offers advantages such as optimizing engine performance, facilitating starting and shutdown procedures, and providing a safety feature.
Step-by-step explanation:
A free-turbine turboshaft engine is a type of engine used in helicopters and some aircraft. It consists of two main components: a gas generator, which produces the high-pressure gas needed for combustion, and a power turbine, which extracts power from the high-pressure gas to drive the output shaft. In a free-turbine design, the power turbine is not directly connected to the gas generator, which allows it to rotate independently of the gas generator.
This design offers several advantages. First, it allows the power turbine to spin at a different speed than the gas generator, which can optimize engine performance at different operating conditions. Second, it allows for easier starting and shutdown procedures, as the power turbine can be brought up to speed before the gas generator starts producing high-pressure gas. Finally, it provides a safety feature, as the power turbine can continue to rotate even if the gas generator fails.