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controls
Secondary control inputs located on the propeller governor include the beta
valve and the fuel governor reset. These controls are used in conjunction
with the propeller low blade angle feedback system and the engine
propeller reversing control system for propeller beta control and reverse
thrust control. A cambox unit is part of the engine control system and its
purpose is to schedule gas generator speed and propeller angle by means
of linkages to the fuel control power lever and to the propeller governor
beta valve and fuel governor reset controls.
Propeller Low Blade Angle Reset Systems
During the development program of an airplane, the most desirable
propeller low pitch limits (primary blade angle) and engine flight idle
settings required for optimum flight handling are determined. In some
cases, certain ground operating requirements such as propeller restricted
speed ranges may dictate a different propeller low pitch limit for ground
operation. Some installations utilize an airframe-supplied propeller low
pitch reset system actuated by means of a switch which senses the weight
of the airplane on the main landing gear. This functionality is integrated
with the engine-supplied propeller beta control system. The system
automatically sets the propeller low pitch limit to either the ground or
light positions.
Automatic Feathering
Takeoff performance for multi-engine aircraft is based upon having one
engine inoperative. Most multi-engine aircraft are equipped with aircraft
manufacturer provided automatic feathering systems to reduce drag on
the aircraft. However these systems are normally not armed during most
other phases of flight. Automatic feathering is not used in single-engine
PT6A engine applications. Please refer to the applicable AFM for specific
operating instructions.
Because the free turbine configuration of the PT6A engine has less rotating
inertia than a fixed turbine engine, an unfeathered propeller creates less
in-flight drag. Therefore, negative torque sensing systems are not required.
controls
Secondary control inputs located on the propeller governor include the beta
valve and the fuel governor reset. These controls are used in conjunction
with the propeller low blade angle feedback system and the engine
propeller reversing control system for propeller beta control and reverse
thrust control. A cambox unit is part of the engine control system and its
purpose is to schedule gas generator speed and propeller angle by means
of linkages to the fuel control power lever and to the propeller governor
beta valve and fuel governor reset controls.
Propeller Low Blade Angle Reset Systems
During the development program of an airplane, the most desirable
propeller low pitch limits (primary blade angle) and engine flight idle
settings required for optimum flight handling are determined. In some
cases, certain ground operating requirements such as propeller restricted
speed ranges may dictate a different propeller low pitch limit for ground
operation. Some installations utilize an airframe-supplied propeller low
pitch reset system actuated by means of a switch which senses the weight
of the airplane on the main landing gear. This functionality is integrated
with the engine-supplied propeller beta control system. The system
automatically sets the propeller low pitch limit to either the ground or
light positions.
Automatic Feathering
Takeoff performance for multi-engine aircraft is based upon having one
engine inoperative. Most multi-engine aircraft are equipped with aircraft
manufacturer provided automatic feathering systems to reduce drag on
the aircraft. However these systems are normally not armed during most
other phases of flight. Automatic feathering is not used in single-engine
PT6A engine applications. Please refer to the applicable AFM for specific
operating instructions.
Because the free turbine configuration of the PT6A engine has less rotating
inertia than a fixed turbine engine, an unfeathered propeller creates less
in-flight drag. Therefore, negative torque sensing systems are not required.
Summary of Contents for PT6A Turboprop
Page 1: ...Key NEW OWNER WISDOm YOUR PT6A turboprop ...
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