The PT6 Engine, Celebrating 50 Years of Excellence, Part 4

This is our final part in our series on the PT6 Engine, which celebrates it’s 50th anniversary this year! Make sure you catch part 1part 2, and part 3 if you haven’t read those yet, before reading this one. In the comments section below, let us know why you love the PT6 Engine

Many in the aviation industry call the PT6 Engine an aircraft that was ahead of its time.  Many of the original design elements were considered liabilities when the engine first appeared, as most aircraft manufacturers felt that piston engines were the better options.  In fact, those original design elements eventually became the standard for airplane engines that came after its development, mostly due to the free turbine layout of the engine.

Starting Easier

The PT6 Engine was the first engine to use a free turbine layout, whereas traditional engines at the time used a single shaft layout.  The single shaft led to limit engine performance and made maintenance difficult.  In the PT6 Engine, the gas generator turbine is not directly attached to the shaft that turns the propeller, so that starting the engine is much easier.   The starter in an engine only needs gas to ignite, and it then sets the rest of the engine in motion.  By disconnecting the turbine from the shaft, the starter does not need as much torque to start the engine so that the starting system is much smaller.

Simple Control System

The use of the free turbine and fuel distribution system allows the engine to require a single hydro-mechanical engine control system, which prevent s the engine from overspeeding and gets enough fuel to do what it is supposed to do.  In addition, the simple hydro-mechanical engine allows for a wider selection of propeller speeds, allowing the propeller to absorb full takeoff power.  This also allows the aircraft to have maximum thrust during takeoff and improves performance.

Other Benefits

PT6 Engine
(Photo courtesy of Vector Aerospace)

Because the PT6 Engine is also a popular choice for helicopters, the engine had to have a less complex simple sprag clutch arrangement compared to fixed turbine engines.  The design also allows the aircraft to use a simple propeller as it is configured with a spring on one side and a hydraulic piston on the other.  If it had required a double-acting propeller, the propeller control system would have been too complex, increasing cost and lowering reliability.

There is no doubt that the PT6 Engine aircraft engine was ahead of its times, and the benefits to aerospace engineering with the development of this engine literally changed aviation history.  For more information regarding the PT6 Engine or about aircraft maintenance services, visit Covington Aircraft online or contact us by phone today at .

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