Systems and methods of operating a tiltrotor aircraft include providing the tiltrotor with a plurality of rotatable pylon assemblies. Each pylon assembly includes a rotor system having a plurality of rotor blades operatively coupled to a rotor mast and selectively rotatable in response to rotation of the rotor mast, a swashplate assembly operatively coupled to the plurality of rotor blades, a plurality of swashplate actuators operatively coupled to the swashplate assembly and selectively extendable and retractable to control the position and the orientation of the swashplate assembly, and a swashplate augmenting system. The swashplate augmenting system is selectively operable to cause axial translation of the swashplate actuators and swashplate assembly to augment the travel of the swashplate actuators in order to fold the plurality of rotor blades for operating the tiltrotor aircraft in an airplane forward flight mode.

CROSS-REFERENCE TO RELATED APPLICATIONS

Not applicable.

Not applicable.

BACKGROUND

Tiltrotor aircraft are generally operable in a helicopter flight mode to ascend from and/or descend to a landing area and in an airplane flight mode to propel the aircraft forward. The transition from the helicopter flight mode to the airplane flight mode, and vice versa, is generally accomplished by selectively pivoting engine or pylon assemblies of the aircraft between a vertical orientation and a horizontal orientation to change the thrust angle of the rotatable aircraft blades. However, tiltrotor aircraft are prone to various aeroelastic instabilities that other aircraft may not experience. This is generally because of the variable thrust angles and forward flight speeds achieved by such tiltrotor aircraft.

DETAILED DESCRIPTION

Referring toFIGS. 1 through 4, oblique views of a tiltrotor aircraft100configured for operation in a helicopter flight mode, configured for operation in a proprotor forward flight mode, configured in transition from the proprotor forward flight mode to an airplane forward flight mode, and configured for operation in the airplane forward flight mode, are shown respectively. Tiltrotor aircraft100comprises a fuselage102, a plurality of wings104extending from the fuselage102, and a tail assembly106having control surfaces operable for horizontal and/or vertical stabilization during forward flight. Each of the wings104comprises a pivotable pylon assembly108located proximate to the outboard end of each wing104. The pylon assemblies108or portions thereof are generally rotatable relative to the fuselage102between a generally vertical orientation having a vertically-oriented thrust angle associated with the helicopter flight mode (shown inFIG. 1) and a generally horizontal orientation having a horizontally-oriented thrust angle associated with the proprotor forward flight mode (shown inFIG. 2). However, it will be appreciated that tiltrotor aircraft100may also be operated when the pylon assemblies108or portions thereof are selectively positioned between the helicopter mode and the proprotor forward flight mode, referred to as a conversion flight mode.

Pylon assemblies108each house an engine, gearbox, and/or other drive system components used to selectively rotate an associated rotor system110comprising a plurality of rotor blades112. In the embodiment shown, each pylon assembly108comprises a proprotor gearbox114. When rotor systems110are driven, the plurality of rotor blades112are operable to be rotated as shown inFIGS. 1 and 2, feathered, stopped, clocked and subsequently locked as shown inFIG. 3, and folded as shown inFIG. 4. In the embodiment shown, rotor systems110are rotated responsive to torque and rotational energy provided by one or more engines116via an interconnect driveshaft system (not shown), proprotor gearboxes114, and rotor masts122. Further, engines116may be disposed in engine pods118and comprise convertible engines operable in each of a turboshaft mode (shown inFIGS. 1 and 2) to selectively impart rotation to the rotor systems110and a turbofan mode (shown inFIGS. 3 and 4) to provide forward thrust to tiltrotor aircraft100.

FIG. 1shows tiltrotor aircraft100in the helicopter flight mode, in which rotor systems110are rotating in a substantially horizontal plane to produce vertically-oriented thrust, in the form of vertical lift, to the tiltrotor aircraft100.FIG. 2shows tiltrotor aircraft100in the proprotor forward flight mode, in which rotor systems110are rotating in a substantially vertical plane to provide horizontally-oriented forward thrust, thereby enabling the wings104to provide a lifting force to tiltrotor aircraft100responsive to forward airspeed and enabling tiltrotor aircraft100to fly similarly to a conventional propeller-driven aircraft. In each of these configurations, engines116are operated in the turboshaft mode. In the turboshaft mode, hot combustion gases from each engine116cause selective rotation of the rotary propulsion system of tiltrotor aircraft100, including engines116, proprotor gearboxes114, and rotor systems110to propel the tiltrotor aircraft100in each of the helicopter flight mode and the proprotor forward flight mode.

In each of the helicopter flight mode and the proprotor forward flight mode (collectively, rotary flight modes) of tiltrotor aircraft100, rotor systems110are rotated in opposing directions to provide torque balance to the tiltrotor aircraft100. In the embodiment shown, when viewed from the top of the tiltrotor aircraft100in the helicopter flight mode (FIG. 1) or the front of tiltrotor aircraft100in the proprotor forward flight mode (FIG. 2), the left rotor system110and associated rotor blades112rotate in a counterclockwise direction, and the right rotor system110and associated rotor blades112rotate in a clockwise direction. However, in other embodiments, the rotation direction of each of the left and right rotor systems110may be reversed. Additionally, in the embodiment shown, each rotor system110comprises three rotor blades112. However, in alternative embodiments, each rotor system110may comprise any number of rotor blades112, so long as each rotor system110comprises the same number of rotor blades112.

FIG. 3shows tiltrotor aircraft100in transition from the proprotor forward flight mode to the airplane forward flight mode. During the transition from the proprotor forward flight mode to the airplane forward flight mode, the torque path between engines116and rotor systems110is interrupted, and the rotor blades112are feathered, or oriented to be streamlined in the direction of flight such that a chord length of each rotor blade112is substantially aligned with the forward flight direction of the tiltrotor aircraft100. The feathered rotor blades112thereby act as aerodynamic brakes to slow rotation of the rotor systems110, until rotation of the rotor systems110ceases. In some embodiments, the rotor systems110may be clocked, or stopped in a predetermined or known position to prevent contact of the rotor blades112with the wings104and/or to align each rotor blade112with a respective slot124in a pylon assembly108when the rotor blades112are folded. In this configuration, engines116have transitioned to operating in the turbofan mode. In the turbofan mode, hot combustion gases in each engine116cause rotation of a power turbine coupled to an output shaft that is used to power a fan that forces bypass air through the engine116to produce forward thrust. This enables the tiltrotor aircraft100to fly similarly to a conventional jet aircraft since the rotor systems110are no longer providing thrust to tiltrotor aircraft100, and the wings104are provide a lifting force responsive to forward airspeed of the tiltrotor aircraft100.

FIG. 4illustrates tiltrotor aircraft100in the airplane forward flight mode. In the airplane forward flight mode, the rotor blades112have been folded to be oriented substantially parallel to their respective pylon assemblies108in order to minimize drag. To prevent chatter or other movement of the rotor blades112when folded, the rotor blades112may be received within slots124of pylon assemblies108. In some embodiments, the rotor blades112may be folded substantially ninety degrees. However, in other embodiments, the rotor blades112may be folded beyond ninety degrees. In this configuration, engines116are operating in the turbofan mode to produce thrust in order to propel the tiltrotor aircraft100forward. As such, the airplane forward flight mode is generally associated with high speed forward flight, with speeds exceeding those that may induce whirl flutter or other aeroelastic instabilities in the rotor systems110when the tiltrotor aircraft100is operated in the proprotor forward flight mode.

Referring toFIGS. 5 through 8, side, partial oblique left side, and partial oblique right side views of the rotor system110of tiltrotor aircraft100with a swashplate augmenting system150configured in a retracted position, and a side view of the rotor system110with the swashplate augmenting system150configured in an extended position, respectively, are shown. Rotor system110comprises rotor mast122coupled to a rotor hub126, which may be gimballed or non-gimballed. Rotor hub126comprises one or more yokes128used to coupled the rotor blades112to the rotor hub126while allowing the blades to flap relative to the rotor mast122in out-of-plane directions. In some embodiments, the rotor hub126may comprise a plurality of rotor grips130configured to couple an associated rotor blade112to the rotor hub126and/or an associated yoke128. Each rotor grip130is also operationally coupled with a pitch horn132that is coupled to a rotatable ring134of a rise-and-fall swashplate assembly136via a pitch link138. The swashplate assembly136comprises a non-rotatable ring140engaged with the rotatable ring134and configured to guide and/or alter the position, pitch, tilt, angle, orientation, and/or translation of the rotatable ring134. Additionally, it will be appreciated that a bearing and/or other friction-reducing component may be disposed between the rotatable ring134and the non-rotatable ring140to reduce friction and maintain the engaged configuration between the rotatable ring134and the non-rotatable ring140of the swashplate assembly136during operation.

In the embodiment shown, the rotatable ring134is generally affixed to the rotor mast122and rotates with the rotation of the rotor mast122, while the non-rotatable ring140is mounted about the rotor mast122and remains stationary with respect to rotation of the rotor mast122and the rotatable ring134. A plurality of swashplate actuator systems142are coupled to the non-rotatable ring140of the swashplate assembly136. Each swashplate actuator system142comprises a plurality of actuators144that are selectively extendable and retractable to control the position, pitch, tilt, angle, orientation, and/or translation of the non-rotatable ring140, which is then translated to the rotatable ring134. As the rotatable ring134rotates with the rotor mast122, each pitch link138is axially driven through engagement of the rotatable ring134with the non-rotatable ring140, thereby driving the pitch horns132to rotate each rotor grip130and associated rotor blade112to selectively adjust the pitch of each of the rotor blades112of tiltrotor aircraft100. This allows the pitch of each of the rotor blades112to be selectively controlled through selective extension and retraction of the actuators144of the swashplate actuator systems142. In the embodiment shown, rotor system110comprises three swashplate actuator systems142, each comprising three actuators144. However, depending on the configuration of the tiltrotor aircraft100, any number of swashplate actuator systems142or actuators144may be used.

Opposite the non-rotatable ring140of the swashplate assembly136, the plurality of swashplate actuator systems142are coupled to a swashplate augmenting system150comprising an axially translatable mounting ring152, mounting ring guide154, primary linkage156, secondary linkage158, and an actuator system160comprising a plurality of cylinders162. The swashplate actuator systems142are generally coupled to the mounting ring152and proportionally disposed about the mounting ring152. The mounting ring152is generally axially translatable along the rotor mast122to augment the travel of the actuators144of the swashplate actuator systems142. A mounting ring guide154or plurality of mounting ring guides154may be disposed on a rotor mast housing146and configured to guide the mounting ring152during axial motion and/or prevent angular binding of the mounting ring152about the rotor mast housing146.

In the embodiment shown, primary linkage156and mounting ring152are pivotally coupled at a midpoint of each of the primary linkage156and the mounting ring152on opposing sides of the mounting ring152. As such, the primary linkage156extends around the gearbox114. The primary linkage156is also pivotally coupled to an actuator system160comprising a plurality of cylinders162on a first side (left side) and to a secondary linkage158on the opposing side (right side). As such, the secondary linkage158forms a horseshoe-shaped linkage and is pivotally coupled to the primary linkage156at a midpoint of the horseshoe and to a stationary housing148of the gearbox114or other stationary structure of the tiltrotor aircraft100on each side of the gearbox114at each end of the horseshoe. Thus, in some embodiments, the connection between the primary linkage156and the mounting ring152and the connection between the secondary linkage158and the housing148of the gearbox114may be axially aligned along the rotor mast122and located on the same front and back sides of the gearbox114. Further, opposite the primary linkage156, the actuator system160is pivotally coupled to the stationary housing148of the gearbox114. However, in other embodiments, the actuator system160may be pivotally coupled to any component or portion of the pylon assembly108, gearbox114, or other component of the tiltrotor aircraft100within the pylon assembly108of the tiltrotor aircraft100.

In the embodiment shown, swashplate augmenting system150comprises a single actuator system160having multiple cylinders162. However, at least in some embodiments, the actuator system160may comprise only a single cylinder162or any number of cylinders162. In other embodiments, any number of actuator systems160having any number of cylinders162may be used. The actuator system160may generally be substantially similar to the swashplate actuator systems142and comprise hydraulic actuators, electromechanical actuators, jack screw type actuators, or any other suitable actuators that allow selective extension and retraction. In operation, the actuator system160may be selectively extended (shown by D2inFIG. 8) and retracted (shown by D1inFIGS. 5 through 7), and through the linkage156,158, operate to axially move the mounting ring152along the rotor mast122, thereby causing the swashplate assembly136to rise and fall, respectively. Accordingly, extension of the actuator system160moves the mounting ring152from the retracted position (P1inFIGS. 5 through 7) towards the rotor hub126to the extended position (P2inFIG. 8) causing the actuators144of the swashplate actuator systems142to also move towards the rotor hub126. This augments the travel of the actuators144of the swashplate actuator systems142and extends the overall travel of the swashplate assembly136. Similarly, retraction of the actuator system160moves the mounting ring152away from the rotor hub126causing the actuators144of the swashplate actuator systems142to also move away from the rotor hub126. As such, in some embodiments, swashplate augmenting system150may be used to augment the travel of the actuators144of the swashplate actuator systems142to adjust a pitch of the rotor blades112. However, more specifically, swashplate augmenting system150is used to fold the rotor blades112for operating tiltrotor aircraft100in the airplane forward flight mode as shown inFIG. 4.

As shown inFIGS. 5 through 7, the swashplate augmenting system150is in the fully retracted position (P1), and the swashplate actuator systems142are partially extended and actively controlling the pitch of the rotor blades112. This is applicable when the tiltrotor aircraft100is operated in the rotary flight modes ofFIGS. 1 and 2, such that the swashplate augmenting system150remains retracted to allow the swashplate actuator systems142to control the pitch of rotor blades112. Additionally, the swashplate augmenting system150remains retracted when the rotor blades112are feathered by the swashplate actuator systems142as shown inFIG. 3. To feather the rotor blades112as shown inFIG. 3, the swashplate actuator systems142retract fully to move the swashplate assembly136to its furthest location from the rotor hub126. This adjusts the pitch of the rotor blades112, such that a chord length of each rotor blade112is substantially aligned with the forward flight direction of the tiltrotor aircraft100. In this manner, swashplate augmenting system150is not used for collective control or feathering of the rotor blades112and remains stationary to provide a stable base or platform for the swashplate actuator systems142to precisely control the pitch of the rotor blades112.

Once the rotor blades112are feathered via retraction of the swashplate actuator systems142, the rotor blades112can be folded to the folded position shown inFIG. 4. To fold the rotor blades112, fold linkage131used to lock the position of the rotor blades112may be selectively disengaged while the swashplate actuator systems142remain fully retracted. Once unlocked, the swashplate actuator systems142may be selectively extended to move the swashplate assembly136towards the rotor hub126in order to at least partially fold the rotor blades112. The swashplate actuator systems142may extend fully to provide the maximum amount of fold, which is limited by the throw or maximum extension length of the actuators144. However, to fully fold the rotor blades112to the folded position, additional swashplate travel is required. Thus, the actuator system160of the swashplate augmenting system150may be selectively extended (shown by D2inFIG. 8) to move the mounting ring152to the extended position (P2inFIG. 8). This further moves the swashplate actuator systems142and swashplate assembly136towards the rotor hub126to fully fold the rotor blades112to their fully folded positions. Thus, the travel of the swashplate assembly136provided by the swashplate actuator systems142is augmented, and consequently increased, by the swashplate augmenting system150. Further, once folded, fold linkage131may be selectively engaged to lock the rotor blades112in the folded position. Still further, in some embodiments, the fold linkage131may be prevented from disengaging when the rotor blades112are not feathered.

The swashplate augmenting system150allows the rotor blades112of the tiltrotor aircraft100to be folded and oriented substantially parallel to their respective pylon assemblies108in order to minimize drag when the tiltrotor aircraft100is operated in the airplane forward flight mode. The swashplate augmenting system150remedies the problem of traditional swashplate actuators not having the requisite travel to fully fold the rotor blades112. As such, it will be appreciated that swashplate augmenting system150may provide, for example, an additional five to six inches of travel. However, in some embodiments, swashplate augmenting system150may provide more or less additional travel. Furthermore, swashplate augmenting system150circumvents potential buckling failures that may be incurred if longer swashplate actuators were used. During folding and/or unfolding of the rotor blades112, high speed or force may not be required. Thus, actuator system160may be designed and/or configured accordingly.

Because the swashplate augmenting system150provides additional travel to the swashplate assembly136to enable folding of the rotor blades112, the swashplate assembly136, swashplate actuator systems142, and swashplate augmenting system150may collectively be referred to as an augmented swashplate assembly. It will be appreciated that the steps to fold the rotor blades112may be performed in substantially reverse order to unfold the rotor blades112in order to transition from the airplane forward flight mode to one of the rotary flight modes (forward flight proprotor mode and/or helicopter mode) by disengaging the fold linkage131, retracting the swashplate assembly136via selective retracting of the swashplate actuator systems142and swashplate augmenting system150, engaging the fold linkage131to lock the rotor blades112in the unfolded position (shown inFIG. 3), and then selectively extending the swashplate actuator systems142to adjust pitch of the rotor blades112for flight in the rotary flight modes (shown inFIGS. 1 and 2). Furthermore, tiltrotor aircraft100generally comprises a flight control system configured to selectively control the operation, orientation, rotation, and/or position of the pivotable pylon assemblies108, rotor systems110, and/or rotor blades112of the tiltrotor aircraft100. Control of the operation of the tiltrotor aircraft100by the flight control system may be in response to inputs (e.g., collective control) made by a pilot and/or may be at least partially automated.

Referring toFIGS. 9 and 10, side views of the rotor system110of tiltrotor aircraft100are shown with an alternative embodiment of a swashplate augmenting system250configured in a retracted position and an extended position, respectively. Swashplate augmenting system250is similar to swashplate augmenting system150and is configured to operate in a substantially similar manner to provide additional travel to the swashplate assembly136to enable folding of the rotor blades112of tiltrotor aircraft100. However, in the embodiment shown, swashplate augmenting system250does not utilize the mechanical linkage156,158of swashplate augmenting system150to provide a mechanical advantage. Instead, swashplate augmenting system250utilizes mounting ring252that employs a serial connection between the swashplate actuator systems142and a plurality of actuator systems260. As such, in the embodiment shown, swashplate augmenting system250comprises three actuator systems260, each having three cylinders262. However, at least in some embodiments, actuator systems260may comprise only a single cylinder262or any number of cylinders262. In other embodiments, any number of actuator systems260having any number of actuators260may be used. Accordingly, in other embodiments, the actuator systems260may not be serially connected and instead be offset circumferentially about the mounting ring252.

Actuator system260may generally be substantially similar to actuator system160and/or the swashplate actuator systems142and comprise hydraulic actuators, electromechanical actuators, jack screw type actuators, or any other suitable actuators that allow selective extension and retraction. In operation, the actuator system260may be selectively extended (shown by D2inFIG. 10) and retracted (shown by D1inFIG. 9) simultaneously to axially move the mounting ring252along the rotor mast122, thereby causing the swashplate assembly136to rise and fall, respectively. Accordingly, extension of the actuator system260moves the mounting ring252from the retracted position (P1inFIG. 9) towards the rotor hub126to the extended position (P2inFIG. 10) causing the actuators144of the swashplate actuator systems142to also move towards the rotor hub126. This augments the travel of the actuators144of the swashplate actuator systems142and extends the overall travel of the swashplate assembly136. Similarly, retraction of the actuator system260moves the mounting ring252away from the rotor hub126causing the actuators144of the swashplate actuator systems142to also move away from the rotor hub126. As such, in some embodiments, swashplate augmenting system250may be used to augment the travel of the actuators144of the swashplate actuator systems142to adjust a pitch of the rotor blades112. However, more specifically, swashplate augmenting system250is used to fold the rotor blades112for operating tiltrotor aircraft100in the airplane forward flight mode as shown inFIG. 4in a substantially similar manner to swashplate augmenting system150.

While the embodiments shown depict tiltrotor aircraft100, it will be appreciated that swashplate augmenting systems150,250may be used in any other aircraft and/or rotorcraft requiring additional swashplate travel, that may for example, be used to fold the rotor blades112and/or reduce the duty cycle and/or collective stroke required of a given swashplate assembly136. This is applicable to both “manned” and “un-manned” aircraft. Folding of the rotor blades112may be used during operation of an aircraft in the airplane forward flight mode and/or for compact storage of an aircraft. In some embodiments, by folding the rotor blades112during storage of an aircraft, safety in a landing zone or hangar may be increased by preventing a person from contacting unfolded rotor blades112. Furthermore, it will be appreciated that swashplate augmenting systems150,250may be retrofit with existing aircraft and/or rotorcraft.

Referring toFIG. 11, a flowchart of a method300of operating a tiltrotor aircraft100is shown. Method300begins at block302by providing a tiltrotor aircraft100comprising a plurality of rotor systems110, each rotor system110comprising a plurality of rotor blades112, a swashplate assembly136, a plurality of swashplate actuator systems142, and a swashplate augmenting system150,250. Method300continues at block304by operating the tiltrotor aircraft100in a proprotor forward flight mode. Method300continues at block306by operating the swashplate actuator systems142to feather the plurality of rotor blades112. In some embodiments, the swashplate actuator systems142may be retracted in order to axially move the swashplate assembly136. Method300continues at block308by disengaging fold linkage131to unlock the rotor blades112from an unfolded position. Method300continues at block310by operating the swashplate actuator systems142and the swashplate augmenting system150,250to fold the rotor blades112. In some embodiments, the fold linkage131may be engaged after the rotor blades112are folded to lock the rotor blades112in the folded position.

Referring now toFIG. 12, a schematic diagram of a general-purpose processor (e.g. electronic controller or computer) system500suitable for implementing the embodiments of this disclosure is shown. System500that includes a processing component510suitable for implementing one or more embodiments disclosed herein. In particular, a flight control system of tiltrotor aircraft100configured to control operation of the rotor systems110and swashplate augmenting systems150,250and/or other electronic systems disclosed herein may comprise one or more systems500. In addition to the processor510(which may be referred to as a central processor unit or CPU), the system500might include network connectivity devices520, random access memory (RAM)530, read only memory (ROM)540, secondary storage550, and input/output (I/O) devices560. In some cases, some of these components may not be present or may be combined in various combinations with one another or with other components not shown. These components might be located in a single physical entity or in more than one physical entity. Any actions described herein as being taken by the processor510might be taken by the processor510alone or by the processor510in conjunction with one or more components shown or not shown in the system500. It will be appreciated that the data described herein can be stored in memory and/or in one or more databases.

The processor510executes instructions, codes, computer programs, or scripts that it might access from the network connectivity devices520, RAM530, ROM540, or secondary storage550(which might include various disk-based systems such as hard disk, floppy disk, optical disk, or other drive). While only one processor510is shown, multiple processors may be present. Thus, while instructions may be discussed as being executed by processor510, the instructions may be executed simultaneously, serially, or otherwise by one or multiple processors510. The processor510may be implemented as one or more CPU chips and/or application specific integrated chips (ASICs).

The network connectivity devices520may take the form of modems, modem banks, Ethernet devices, universal serial bus (USB) interface devices, serial interfaces, token ring devices, fiber distributed data interface (FDDI) devices, wireless local area network (WLAN) devices, radio transceiver devices such as code division multiple access (CDMA) devices, global system for mobile communications (GSM) radio transceiver devices, worldwide interoperability for microwave access (WiMAX) devices, and/or other well-known devices for connecting to networks. These network connectivity devices520may enable the processor510to communicate with the Internet or one or more telecommunications networks or other networks from which the processor510might receive information or to which the processor510might output information.

The network connectivity devices520might also include one or more transceiver components525capable of transmitting and/or receiving data wirelessly in the form of electromagnetic waves, such as radio frequency signals or microwave frequency signals. Alternatively, the data may propagate in or on the surface of electrical conductors, in coaxial cables, in waveguides, in optical media such as optical fiber, or in other media. The transceiver component525might include separate receiving and transmitting units or a single transceiver. Information transmitted or received by the transceiver525may include data that has been processed by the processor510or instructions that are to be executed by processor510. Such information may be received from and outputted to a network in the form, for example, of a computer data baseband signal or signal embodied in a carrier wave. The data may be ordered according to different sequences as may be desirable for either processing or generating the data or transmitting or receiving the data. The baseband signal, the signal embedded in the carrier wave, or other types of signals currently used or hereafter developed may be referred to as the transmission medium and may be generated according to several methods well known to one skilled in the art.

The RAM530might be used to store volatile data and perhaps to store instructions that are executed by the processor510. The ROM540is a non-volatile memory device that typically has a smaller memory capacity than the memory capacity of the secondary storage550. ROM540might be used to store instructions and perhaps data that are read during execution of the instructions. Access to both RAM530and ROM540is typically faster than to secondary storage550. The secondary storage550is typically comprised of one or more disk drives or tape drives and might be used for non-volatile storage of data or as an over-flow data storage device if RAM530is not large enough to hold all working data. Secondary storage550may be used to store programs or instructions that are loaded into RAM530when such programs are selected for execution or information is needed.

The I/O devices560may include liquid crystal displays (LCDs), touchscreen displays, keyboards, keypads, switches, dials, mice, track balls, voice recognizers, card readers, paper tape readers, printers, video monitors, transducers, sensors, motor drive electronics, or other well-known input or output devices. Also, the transceiver525might be considered to be a component of the I/O devices560instead of or in addition to being a component of the network connectivity devices520. Some or all of the I/O devices560may be substantially similar to various components disclosed herein and/or may be components of the flight control system of tiltrotor aircraft100configured to control operation of the rotor systems110and swashplate augmenting systems150,250.

At least one embodiment is disclosed, and variations, combinations, and/or modifications of the embodiment(s) and/or features of the embodiment(s) made by a person having ordinary skill in the art are within the scope of this disclosure. Alternative embodiments that result from combining, integrating, and/or omitting features of the embodiment(s) are also within the scope of this disclosure. Where numerical ranges or limitations are expressly stated, such express ranges or limitations should be understood to include iterative ranges or limitations of like magnitude falling within the expressly stated ranges or limitations (e.g., from about 1 to about 10 includes, 2, 3, 4, etc.; greater than 0.10 includes 0.11, 0.12, 0.13, etc.). For example, whenever a numerical range with a lower limit, Rl, and an upper limit, Ru, is disclosed, any number falling within the range is specifically disclosed. In particular, the following numbers within the range are specifically disclosed: R=Rl+k*(Ru−Rl), wherein k is a variable ranging from 1 percent to 100 percent with a 1 percent increment, i.e., k is 1 percent, 2 percent, 3 percent, 4 percent, 5 percent, . . . 50 percent, 51 percent, 52 percent, . . . , 95 percent, 96 percent, 95 percent, 98 percent, 99 percent, or 100 percent. Moreover, any numerical range defined by two R numbers as defined in the above is also specifically disclosed.

Use of the term “optionally” with respect to any element of a claim means that the element is required, or alternatively, the element is not required, both alternatives being within the scope of the claim. Use of broader terms such as comprises, includes, and having should be understood to provide support for narrower terms such as consisting of, consisting essentially of, and comprised substantially of. Accordingly, the scope of protection is not limited by the description set out above but is defined by the claims that follow, that scope including all equivalents of the subject matter of the claims. Each and every claim is incorporated as further disclosure into the specification and the claims are embodiment(s) of the present invention. Also, the phrases “at least one of A, B, and C” and “A and/or B and/or C” should each be interpreted to include only A, only B, only C, or any combination of A, B, and C.