The present disclosure relates generally to aircraft propeller control, and more particularly to feathering a propeller.
For propeller driven aircraft, a control system may adjust the blade angle of the propeller blades to a feather position to reduce forward drag on the aircraft. For example, a propeller electronic controller may control a feather solenoid and a protection solenoid, which both have the ability to drive the propeller blades to the feather position. An additional solenoid connected to a lever in the cockpit of the aircraft is typically provided for emergency purposes to feather the propeller. However, this additional solenoid adds weight and additional cost to the overall propeller system.
As such, there is a need for improvement.
In one aspect, there is provided a system comprising a solenoid configured to cause a propeller to feather when the solenoid is energized, an electronic controller connected to the solenoid through a first electrical connection for energizing the solenoid to feather the propeller, and a mechanism connected to the solenoid through a second electrical connection for energizing the solenoid to feather the propeller, the second electrical connection being independent from the first electrical connection.
In another aspect, there is provided a method for feathering a propeller. The method comprises energizing a solenoid to feather the propeller when a first request to energize the solenoid is received from an electronic controller through a first electrical connection with the solenoid and energizing the solenoid to feather the propeller when a second request to energize the solenoid is received from a secondary mechanism through a second electrical connection with the solenoid, the second electrical connection being independent from the first electrical connection.
In another aspect, there is provided a method comprising connecting a solenoid to an electronic controller through a first electrical connection, the solenoid is configured to cause a propeller to feather when the solenoid is energized by the electronic controller through the first electrical connection, and connecting the solenoid to a secondary mechanism through a second electrical connection, the solenoid is configured to cause the propeller to feather when the solenoid is energized by the secondary mechanism through the second electrical connection, the second electrical connection being independent from the first electrical connection.
Reference is now made to the accompanying figures in which:
It will be noted that throughout the appended drawings, like features are identified by like reference numerals.
With reference to
The solenoid 210 is an electro-hydraulic actuator used to adjust the blade angle of the propeller 120. The solenoid 210 is considered energized when at least one coil of the solenoid 210 is energized. When the coil of the solenoid 210 is energized, a solenoid valve is actuated to adjust a supply of hydraulic fluid to the propeller 120 to drive the blade angle of the propeller 120 towards the feather position. The solenoid 210 when energized may hydraulically by-pass a pitch modulation actuator, for example, such as a pitch change unit, used for fine adjustment of propeller blade angle over the full range of the propeller blade pitch. In some embodiments, the solenoid 210 is a feather solenoid, which may be used for a routine feather or an autofeather operation. In some embodiments, the solenoid 210 is a protection solenoid, which may be used when propeller overspeed is detected or if the propeller blade angle is below a minimum allowable in-flight blade angle.
It should be appreciated that by connecting the secondary mechanism 230 to the same solenoid 210 that the electronic controller 220 is connected thereto, that a dedicated emergency solenoid conventionally connected to the secondary mechanism 230 may be eliminated and that the overall weight and/or cost of the propeller system may be reduced.
The electronic controller 220 may be any suitable electronic controller configured to energize the solenoid 210 for feathering the propeller 120. For example, the electronic controller 220 may close at least one switch to energize the solenoid 210 via the first electrical connection 201. The electronic controller 220 may energize the solenoid 210 in response to detecting that the propeller 120 should be driven to the feather position. For example, the electronic controller 220 may command the propeller blade angle to the feather position for a routine feather preceding a shutdown of the engine 100 on-ground. The electronic controller 220 may command the propeller blade angle to the feather position for an autofeather, for example, when the engine 100 has failed during takeoff. The electronic controller 220 may command the propeller blade angle to the feather position when the rotational speed of the propeller exceeds a threshold to protect the propeller 120 from overspeed. The electronic controller 220 may command the propeller blade angle to the feather position when the blade angle of the propeller 120 is below the minimum in-flight propeller blade angle. In some embodiments, the electronic controller 220 energizes the solenoid 210 in response to receiving a feather command from an engine or aircraft computer, for example, used to detect when the propeller 120 should be driven to the feather position. In some embodiments, the electronic controller 220 is a propeller electronic controller.
In some embodiments, the secondary mechanism 230 is an emergency mechanism which may be actuated for an emergency feather of the propeller 120. The secondary mechanism 230 may be any suitable mechanism configured to energize the solenoid 210 for feathering the propeller 120. For example, the secondary mechanism 230 may close at least one switch to energize the solenoid 210 via the second electrical connection 202. The secondary mechanism 230 may comprise a non-electronic controller. For example, the secondary mechanism 230 may be a mechanism that is mechanical, pneumatic, hydraulic or a combination thereof. The secondary mechanism 230 may comprise a mechanical lever in the aircraft that when actuated by a flight crew member (e.g., the pilot or other personnel) causes the solenoid 210 to be energized. For example, the mechanical lever may be operable to close at least one switch to energize the solenoid 210 when the mechanical level is actuated. The mechanical lever may be known as a fire handle. The secondary mechanism 230 may comprise an electronic controller. For example, a second electronic controller (i.e., separate from the first electronic controller 220) may be operable to close a least one switch to energize the solenoid 210 when an actuator (e.g., a push-button, an illuminated button, a switch, a dial, a knob, any other suitable interface, or the like) connected to the second electronic controller is actuated. The second electronic controller may be an aircraft computer.
In some embodiments, the secondary mechanism 230 is connected to the electronic controller 220 via a connection 203 and is configured to provide the electronic controller 210 an indication when the secondary mechanism 230 is actuated. In some embodiments, the electronic controller 220 is configured to disable energizing of the solenoid 210 with the electronic controller 220 in response to receiving the indication. For example, the electronic controller 220 may disable energizing of the solenoid 210 for autofeather, routine feather, propeller overspeed protection, minimum in-flight propeller blade angle, and/or the like. In some embodiments, the electronic controller 220 is configured to disable fault detection of at least one switch used to energize the solenoid 210 through the first electrical connection 201 in response to receiving the indication. The fault detection of the electronic controller 220 may assess if the electronic controller 220 commanded the energizing of the solenoid 210. If the electronic controller 220 did not command the energizing of the solenoid 210 and solenoid 210 is energized, the electronic controller 220 may detect a fault of at least one switch. When a fault is detected, the fault may be outputted to a display device to indicate the fault. The secondary mechanism 230 may be connected directly or indirectly to the electronic controller 210 for providing the indication. The indication may be provided as an analog or digital signal.
With reference to
In some embodiments, the secondary mechanism 230 is configured to close a high side switch 232 and a low side switch 234 when actuated. When both the high side 232 switch and the low side switch 234 are closed, the coil 211 of the solenoid 210 is energized. As shown, the secondary mechanism 230 is connected to the same solenoid coil 211 that the electronic controller 220 is connected thereto. The high side switch 232 when closed, provides a power source (e.g., a 28 V source, or any other suitable voltage) to the second electrical connection 202 and the low side switch 234 when closed, provides a ground connection to the second electrical connection 202. If either one (or both) of the switches 232, 234 are open, then the coil 211 of the solenoid 210 would not be energized via the second electrical connection 202. If either one (or both) of the switches 222, 224 are open, then the coil 211 of the solenoid 210 may be energized via the second electrical connection 202 by closing switches 232 and 234. One of the switches 232, 234 may by default be kept in the closed position and the secondary mechanism 230 may be configured to close the other one of the switches 222, 224 when actuated. Alternatively, in some embodiments, the secondary mechanism 230 comprises one high side switch or one low side switch operable for energizing the solenoid 210. In some embodiments, the switches 232, 234 can be operated simultaneously by a single control (also known as a “gang switch”) to energize the solenoid 210.
In some embodiments, such as shown in
The reference numeral 250 illustrates the electronic controller 220 and the solenoid 210 position in a zone subject to a possible fire (hereinafter the “fire zone”). As an emergency feather may be required when there is a fire, the hardware and/or components relating to the emergency feather that is positioned in the fire zone 250 may be made of fireproof or fire-resistant materials. Accordingly, in some embodiments, the second electrical connection 202 is a fireproof or fire-resistant connection. In some embodiments, the connection 203 between the aircraft computer 240 and the electronic controller 220 is a fireproof or fire-resistant connection.
With reference to
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In some embodiments, as illustrated in
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A diode 225A or 2258 may be positioned between the high side switch 222A or 222B of each channel A, B and the solenoid 210 for electrical current backflow protection. The diode 225A may prevent electrical power from the secondary mechanism 230 from damaging the electronic controller 220. Similarly, a diode 235 may be used for electrical current backflow protection to prevent electrical power from the electronic controller 220 from damaging the secondary mechanism 230. Other suitable devices and/or mechanism for backflow protection may be used.
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The memory 414 may comprise any suitable known or other machine-readable storage medium. The memory 414 may comprise non-transitory computer readable storage medium, for example, but not limited to, an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. The memory 414 may include a suitable combination of any type of computer memory that is located either internally or externally to device, for example random-access memory (RAM), read-only memory (ROM), compact disc read-only memory (CDROM), electro-optical memory, magneto-optical memory, erasable programmable read-only memory (EPROM), and electrically-erasable programmable read-only memory (EEPROM), Ferroelectric RAM (FRAM) or the like. Memory 414 may comprise any storage means (e.g., devices) suitable for retrievably storing machine-readable instructions 416 executable by processing unit 412. Note that the computing device 400 can be implemented as part of a full-authority digital engine controls (FADEC) or other similar device, including electronic engine control (EEC), engine control unit (EUC), electronic propeller control, propeller control unit, and the like.
The methods and systems for feathering a propeller described herein may be implemented in a high level procedural or object oriented programming or scripting language, or a combination thereof, to communicate with or assist in the operation of a computer system, for example the computing device 400. Alternatively, the methods and systems for feathering a propeller may be implemented in assembly or machine language. The language may be a compiled or interpreted language. Program code for implementing the methods and systems for feathering a propeller may be stored on a storage media or a device, for example a ROM, a magnetic disk, an optical disc, a flash drive, or any other suitable storage media or device. The program code may be readable by a general or special-purpose programmable computer for configuring and operating the computer when the storage media or device is read by the computer to perform the procedures described herein. Embodiments of the methods and systems for feathering a propeller may also be considered to be implemented by way of a non-transitory computer-readable storage medium having a computer program stored thereon. The computer program may comprise computer-readable instructions which cause a computer, or more specifically the processing unit 412 of the computing device 400, to operate in a specific and predefined manner to perform the functions described herein, for example those described in the method 300 and/or 350.
Computer-executable instructions may be in many forms, including program modules, executed by one or more computers or other devices. Generally, program modules include routines, programs, objects, components, data structures, etc., that perform particular tasks or implement particular abstract data types. Typically the functionality of the program modules may be combined or distributed as desired in various embodiments.
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without departing from the scope of the invention disclosed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure.
Various aspects of the methods and systems for feathering a propeller may be used alone, in combination, or in a variety of arrangements not specifically discussed in the embodiments described in the foregoing and is therefore not limited in its application to the details and arrangement of components set forth in the foregoing description or illustrated in the drawings. For example, aspects described in one embodiment may be combined in any manner with aspects described in other embodiments. Although particular embodiments have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from this invention in its broader aspects. The scope of the following claims should not be limited by the embodiments set forth in the examples, but should be given the broadest reasonable interpretation consistent with the description as a whole.