Turboprop Propeller Engine Control Systems
While the average flyer might not be as familiar with aircraft powered by turboprop engines and propellers, they are found in many single, twin and commuter aircraft. Single and twin engine aircraft use the Pratt & Whitney PT-6 turboprop engine, a popular option with power spanning from 500 to 2,000 shaft horsepower.
Turboprop engines such as the P&W 150 and Rolls Royce AE2100 are used for larger aircraft and can provide up to 5,000 shaft horsepower. Turboprop propellers are powered by a gas turbine engine via reduction-gear assembly, a highly-efficient power source. What follows is a brief introduction to turboprop engines, propellers, and how they work together and separately.
Propeller control systems are segregated into separate types of control: one for flight and the other for ground operation. In flight, the propeller blade angle and fuel flow for a given power level are controlled by a predetermined schedule. If the power dips below the level required for idle flight, the rpm and blade angle schedule will no longer be able to control the engine properly.
Below the ‘flight idle’ power level, the aircraft enters the ground handling range, wherein the propeller blade is no longer controlled by the propeller governor, but instead the power lever position. If the lever is moved below the startup position, the pitch is inverted to provide reverse thrust and deceleration upon landing.
A feature of turboprop engines is that changes in power are not associated with engine speed, but rather turbine inlet temperature. The propeller maintains a constant engine speed during flight, referred to as the 100 percent rated speed, which is the speed at which the most power and performance efficiency is available. Power, and therefore speed, is affected by altering the rate of fuel flow.
Greater fuel flow causes an increase in turbine inlet temperature and a resulting surplus of power, which is transmitted to the propeller in the form of torque. To withstand the increase in torque, the propeller increases its blade angle thereby maintaining the constant engine rpm with additional thrust.
At NSN Fulfillment, owned and operated by ASAP Semiconductor, we can help you find all the turboprop engine and propeller parts for the aerospace, civil aviation, and defense industries. We’re always available and ready to help you find all the parts and equipment you need, 24/7-365. For a quick and competitive quote, email us at sales@nsnfulfillment.com or call us at +1-714-705-4780.
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