Turboprop Aircraft 2020

At the heart of many turboprop aircraft is the dependable Pratt & Whitney Canada PT6 family of engines. They are the most popular turboprop aircraft engines in history and are particularly well-known for their exceptional reliability. The main variant, the PT6A, is available in a wide variety of models, covering the power range between 580 and 1 940 shaft horsepower.

By the 40th anniversary of the Pratt & Whitney’s maiden flight in 2001, including all versions more than 51 000 PT6As had been installed. The engine is used in more than 100 different applications. The engine consists of two sections that can be easily separated for maintenance. In the gas-generator section air enters through an inlet screen into the low-pressure axial compressor. This has three stages on small and medium versions of the engine and four stages on large versions.

The air then flows into a single-stage centrifugal compressor, through the annular reverse-flow combustion chamber and finally through a single-stage compressor turbine that powers the compressors at about 45,000 rpm. The hot gas from the gas generator section then flows into a separate power section of the engine, containing a single-stage power turbine driving the power take-off system at about 30,000 rpm.

For turboprop use, this powers a two-stage planetary output reduction gearbox, which turns the propeller at a speed of 1,900 to 2,200 rpm. The exhaust gas then escapes through two side mounted ducts in the power turbine housing and is directed away from the engine in order to provide up to 600 lbs. (2,700 N) of jet thrust.

The engine is arranged such that the power turbines are mounted inside the combustion chamber, reducing overall length.