turboprop

A turboprop is a propulsion system in which a gas turbine engine drives a propeller through a reduction gearbox. The gas turbine core comprises a compressor, combustor, and turbine; the exhaust energy also powers a power-turbine that turns the propeller. In most designs the turbine driving the propeller is a free turbine, allowing the propeller to accelerate independently of the gas-generator spool. A propeller governor adjusts blade pitch to maintain the desired rotor speed, providing variable thrust control.

Turboprops offer high propulsive efficiency at moderate flight speeds, making them well suited for short- to medium-range missions. They generally produce better fuel economy than jet engines at lower speeds and altitudes, although their top speeds are lower than those of turbojets and turbofans. Typical cruise speeds for turboprops fall in the 240–360 knots range, with performance varying by model and configuration. They also tend to have good takeoff and landing performance and can operate from shorter or less-developed airfields due to large low-speed propellers and robust gearboxes.

Usage and examples: turboprops power many regional airliners, business aircraft, and military transport planes. Common examples include the Bombardier Dash 8 (Q-series) and ATR 42/72 regional airliners, the Beechcraft King Air family of turboprops, and the Lockheed C-130 Hercules military transport. Turboprops remain favored where fuel efficiency at modest speeds, reliability, and field performance are prioritized.