What Is a Turboprop Aircraft?
A turboprop aircraft is an aircraft equipped with a turboprop engine utilized as the power source for small or low-subsonic-speed aircraft.
A turboprop engine is a type of gas turbine engine that extracts 90% of the gas energy as rotational energy for the propeller, utilizing the remaining 10% as exhaust jet energy.
A turboprop engine consists of an air intake, a compressor, a combustion chamber, a turbine, and an exhaust port.
Air is taken in through the air intake, compressed as it passes through the compressor, and the compressed air is directed to the combustion chamber. Fuel-injected into the combustion chamber mixes with the compressed air flow, and combustion is initiated by vaporized fuel and a spark from an ignition plug. The expansion energy of the generated gas rotates the turbine connected to both the compressor and the propeller at high speed. The exhaust gas flow produced during ejection from the exhaust port accounts for approximately 10% to 25% of the total thrust generated by the engine.
Uses of Turboprop Aircraft
Turboprop engines were developed to combine the characteristics of both piston engines and jet engines during the transition from piston engine to jet engine aircraft, facilitating a smooth transition. They are employed in aircraft flying at subsonic speeds.
However, there are limitations to achieving high output due to constraints on the size and installation position of the reduction gear system relative to engine output. Additionally, limitations on the maximum speed arise from structural restrictions on propeller rotation speed and the inability to significantly reduce the aircraft’s aerodynamic resistance.
Although used extensively for low-speed aircraft in the latter half of the 20th century, and being gradually replaced by high-performance engines, turboprop aircraft are currently employed in small transport planes and twin-engine light aircraft, typically accommodating around several dozen passengers.
They are also utilized for transporting vaccines to remote islands.