Pratt & Whitney Canada’s PT-6 is regarded as one of the best engines in the aviation industry. Read on to learn more about why the PT-6 excels.
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The History of the PT6
In the mid-1950s, Pratt & Whitney Canada president Ronald Riley saw a gap in the market for engines with higher powerto-weight ratios. He encouraged engineering manager Dick Guthrie to create a turboprop engine to replace the firm’s piston engines.
In 1958, Pratt & Whitney Canada began developing a turboprop engine delivering 450 shaft horsepower. After a successful test run on a Beech 18 aircraft in 1961, full-scale production on the engine, dubbed the PT-6, commenced in 1963.
By 2014, more than 50 years after its first flight, over 53,000 PT-6s had been delivered to power more than 140 different aircrafts. According to Raymond Pelletier, PT-6 Project Engineering Manager, improvements have made the current PT-6 up to four times more powerful than the original model. These include a 40 percent better power-to-weight ratio and up to 20 percent better specific fuel consumption. These advancements have helped the PT-6 remain Pratt & Whitney Canada’s most popular engine.
Aircrafts Using the PT-6
The manufacturers of superior single-engine planes, double-engine jets, and helicopters all trust engines from the PT-6 family to power their aircrafts. The U.S. military utilizes the PT-6 models known as T74 or T101. The PT-6B and PT-6C are turboshaft varieties seen in helicopters. But the most common PT-6 is the PT-6A. Engines in this series include the original power range of between 580 and 920 shaft horsepower and the large lines, which boast up to 1,940 shaft horsepower. These engines are utilized in many commercial aircrafts and private jets, including the Quest Kodiak and Pilatus PC-12 featured in the Mountain Aviation fleet.
Prized for its Reliability
So many aircraft manufacturers employ PT-6 engines because they’re regarded as the most reliable in the industry. Pratt & Whitney Canada’s Single Engine Reliability Teams help ensure these engines perform as customers expect.
“Reliability is the biggest factor and it is where we differentiate ourselves,” explained Nick Kanellias, Pratt & Whitney Canada’s General Aviation general manager told Aviation Week. “That’s where the people who designed the PT-6 really got it right.”
A Closer Look at the PT-6A
The PT-6A was the original PT-6. It continues to be the family’s most popular engine thanks to advancements that improved its fuel efficiency, performance, and durability.
The PT-6A’s innovative configuration has been a key element of its success. Its rearward, reverse flow inlet and forward-facing turbine section make it easy to access and maintain. It’s a two-shaft engine with a multi-stage compressor that’s driven by a single-stage compressor turbine and an independent shaft. This shaft connects the power turbine to the propeller through an epicyclic concentric reduction gearbox.
The nearly 70 different PT-6A engines are categorized as small, medium, and large depending on their power levels. Greater power is achieved by increasing the compressor air flow and the number of power turbine stages.
The various high-quality aircrafts that trust the PT-6 are a testimony to the quality of this celebrated engine.