System and method for controlling a pressure field around an aircraft in flight

A system for controlling a pressure field around an aircraft in flight is disclosed herein. In a non-limiting embodiment, the system includes, but is not limited to, a plurality of pressure sensors that are arranged on the aircraft to measure the pressure field. The system further includes, but is not limited to, a controller that is communicatively coupled with the plurality of pressure sensors. The controller is configured to receive information that is indicative of the pressure field from the plurality of pressure sensors. The controller is also configured to determine when the pressure field deviates from a desired pressure field based on the information. The controller is also configured to transmit an instruction to a movable component onboard the aircraft that will cause the movable component to move in a manner that reduces the deviation.

TECHNICAL FIELD

The present invention generally relates to aircraft and more particularly relates to systems and methods for controlling a pressure field around an aircraft in flight.

BACKGROUND

A quiet supersonic aircraft is a supersonic aircraft that will be able to comply with applicable governmental restrictions on the magnitude of sonic booms for flight over land or over other restricted areas, when such restrictions are set. Quiet supersonic aircraft will be designed to comply with such governmental restrictions when flying at a predetermined supersonic speed (e.g., Mach 1.7) and at predetermined atmospheric conditions (e.g., standard atmospheric conditions) and at predetermined operating conditions (e.g., throttle settings, angle of attack). When flying at the predetermined speed and the predetermined operating conditions through the predetermined atmospheric conditions, a quiet supersonic aircraft will have a pressure field around the aircraft that is substantially free from steep pressure gradients. As used herein, the phrase “steep pressure gradient” refers to a relatively large change in pressure over a relatively short distance.

A pressure field free of steep pressure gradients, when propagated to the ground, can give rise to a sonic boom having a magnitude that falls below governmentally imposed limits. Any deviation from the predetermined supersonic speed or from the predetermined atmospheric conditions or from the predetermined operating conditions may give rise to a steep pressure gradient in the pressure field. If a steep pressure gradient were to form in the pressure field around the aircraft during supersonic flight, this could have an undesirable effect on the magnitude of the sonic boom that propagates to the ground.

The propulsion system of a supersonic aircraft interacts aerodynamically with the airframe and with the pressure field around the supersonic aircraft. For example, the flow of air ingested by the propulsion system's inlet, the cycle at which the propulsion system's engine is operated, or the exhaust plume expelled by the propulsion system's nozzle will interact with the airflow around the supersonic aircraft's airframe. A quiet supersonic aircraft is designed such that when the propulsion system is operating at its design condition, the effect of the propulsion system on the pressure field will not give rise to a relatively steep gradient in the pressure field. As used herein, a reference to the design condition of a propulsion system refers to the predetermined engine cycle, the predetermined Mach speed, the predetermined atmospheric conditions, and the predetermined throttle settings that the engine will be operating at when the aircraft is operating at its design condition.

However, when operation of the propulsion system deviates from the design condition (e.g., throttle settings that deviate from design throttle settings, operation at speeds other than design Mach speed, operation of the engine at an engine cycle that differs from a design engine cycle, operation of the propulsion system in other than the predetermined atmospheric conditions, etc.), the propulsion system can cause a relatively steep gradient to form in the pressure field around the aircraft. This is undesirable.

Accordingly, it is desirable to provide a system that can control the pressure field around an aircraft in flight. In addition, it is desirable to provide a method for controlling the pressure field around an aircraft in flight. Furthermore, other desirable features and characteristics will become apparent from the subsequent summary and detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.

BRIEF SUMMARY

Various embodiments of a system and a method for controlling a pressure field around an aircraft in flight are disclosed herein.

In a first non-limiting embodiment, the system includes, but is not limited to, a plurality of pressure sensors arranged on the aircraft to measure the pressure field. The system further includes, but is not limited to, a controller that is communicatively coupled with the plurality of pressure sensors. The controller is configured to receive information that is indicative of the pressure field from the plurality of pressure sensors, to determine when the pressure field deviates from a desired pressure field based on the information, and to transmit an instruction to a movable component onboard the aircraft that will cause the movable component to move in a manner that reduces the deviation.

In another non-limiting embodiment, the system includes, but is not limited to, a plurality of pressure sensors arranged on the aircraft. Each pressure sensor of the plurality of pressure sensors is positioned to measure a respective air pressure proximate a respective portion of an external surface of the aircraft proximate a propulsion system of the aircraft. The system further includes, but is not limited to, a first movable component that is mounted on the aircraft and that is disposed in a position that alters the pressure field when the first movable component moves while the aircraft is in flight. The system still further includes a controller that is communicatively coupled with the plurality of pressure sensors and that is communicatively connected with the first movable component. The controller is configured to receive information from each pressure sensor indicative of the respective air pressure, to compute a pressure field along the external surface of the aircraft based on the information, to detect a deviation between the pressure field and an anticipated pressure field caused by the propulsion system of the aircraft, and to send a first instruction to the first movable component to move in a manner that diminishes the deviation when the deviation is detected.

In yet another non-limiting embodiment, the method includes, but is not limited to measuring the pressure field with a plurality of pressure sensors arranged on the aircraft. The method further includes, but is not limited to receiving, at a controller, information from the plurality of pressure sensors that is indicative of the pressure field. The method further includes, but is not limited to determining, with the processor, when the pressure field deviates from a desired pressure field based, at least in part, on the information from the plurality of pressure sensors; and transmitting, with the processor, an instruction to a movable component onboard the aircraft that will cause the movable component to move in a manner that reduces the deviation.

DETAILED DESCRIPTION

A system and method for controlling the pressure field around an aircraft in flight are disclosed herein. In an exemplary embodiment of the system, multiple pressure sensors are positioned at various locations on the aircraft and are situated to measure the pressure in the vicinity of corresponding portions of the aircraft's exterior. In some embodiments, the pressure sensors are configured to measure dynamic pressure. In other embodiments, the pressure sensors may be configured to measure static pressure, stagnation pressure, or combinations thereof. In some embodiments, the pressure sensors may be disposed and/or concentrated at positions proximate the aircraft's propulsion system to better measure the effect of the propulsion system on the pressure field around the aircraft.

A controller is communicatively coupled with the plurality of pressure sensors and is configured to receive the pressure readings from each pressure sensor. The controller compiles the pressure readings and determines the nature, parameters, gradients, and other measurable aspects of the pressure field around the aircraft. When the controller detects the presence or formation of a steep pressure gradient in the pressure field, the controller is configured to send an instruction to a movable component on the aircraft. The movable component is disposed in a location that permits it to interact with the air flowing over the exterior of the aircraft or flowing in, around, or through the aircraft's propulsion system. For example, the component may be associated with the aircraft's propulsion system such as an extendable compression surface or articulating fan blades of the engine's compressor. In other examples, the component may be one or more movable flight control surfaces positioned around the exterior of the aircraft. Movement of the movable component will have an impact on the pressure field. The controller will select a movable component that will have an effect on the pressure field that will reduce or offset entirely the steep pressure gradient detected by the controller.

A greater understanding of the system for controlling the pressure field around an aircraft described above and of the method for controlling the pressure field around an aircraft may be obtained through a review of the illustrations accompanying this application together with a review of the detailed description that follows.

FIG. 1is a block diagram illustrating a non-limiting embodiment of a system10for controlling a pressure field around an aircraft12. In the illustrated embodiment, system10includes a plurality14of pressure sensors16. InFIG. 1, plurality14includes many pressure sensors16, only four of which have been illustrated inFIG. 1for ease of illustration. It should be understood that in other embodiments, plurality14may include either a greater or a lesser number of pressure sensors16without departing from the teachings of the present disclosure. The embodiment of system10illustrated inFIG. 1further includes a movable component18and a movable component20. In other embodiments of system10, either a greater or lesser number of movable components may be included. System10further includes a primary controller22and a primary controller24associated with movable component18and movable component20, respectively. System10further includes an electronic data storage unit26and a controller28. In other embodiments, system10may include additional components or fewer components without departing from the teachings of the present disclosure.

Pressure sensors16may comprise any type of pressure sensor, whether now known or hereafter invented, that is configured to measure pressure. In some examples, pressure sensors16may be configured to measure static pressure, dynamic pressure, stagnation pressure, free stream pressure, ambient pressure, or combinations thereof. In the illustrated embodiment, pressure sensors16comprise conventional pressure taps that are directly exposed to the free stream of flowing air adjacent aircraft12. In other embodiments, pressure sensors16may comprise optical pressure sensors such as those used in optical air data systems and that are configured to measure pressure through optical means (e.g., through the use of laser light), without direct contact with the free stream of flowing air proximate the exterior surface of the aircraft.

In the embodiment illustrated inFIGS. 2-6, each pressure sensor16comprises a pressure tap. Each pressure sensor16is mounted so that a portion of each pressure sensor is disposed on or just below the surface of aircraft12and is able to directly contact and sample the free stream of air flowing proximate the pressure sensor. Each pressure sensor16of plurality14is mounted at a known location with respect to the surface of aircraft12and is configured to take pressure readings in the vicinity of that known location. In some examples, each pressure sensor16may be configured to measure the pressure at a predetermined distance spaced apart from the surface of aircraft12(e.g., one foot, one meter, etc.).

As illustrated inFIG. 1, each pressure sensor16is communicatively coupled with controller28. A direct hardwired connection between each pressure sensor16and controller28is illustrated inFIG. 1. In other embodiments, such communicative coupling may be accomplished in any suitable manner including, but not limited to, the use of a communication bus, the use of wireless communications, and combinations thereof. Pressure sensors16are each configured to provide respective pressure readings to controller28that are indicative of the pressure conditions in their vicinity. Such pressure readings are delivered to controller28via the communicative coupling between each pressure sensor16and controller28.

Movable components18and20may comprise any component on the aircraft that is both configured for movement and which will alter the pressure field around aircraft12when it moves. For example, the control surfaces (e.g., ailerons, rudder, flaps, slats, etc.) of aircraft12will each affect the pressure field around aircraft12when they move while aircraft12is in flight. Further, various components of the propulsion system of aircraft12will also affect the pressure field around aircraft12when they move. For example, changes to the engine cycle may impact the rate at which air enters and/or exits the propulsion system and therefore will affect the pressure field around aircraft12. Movable/extendable inlet compression surfaces and nozzle surfaces will also impact the rate and conditions under which air enters the propulsion system and the rate and conditions at which air exits the propulsion system when they are moved/extended. Accordingly, movement of such extendable compression surfaces and nozzle plugs may affect the pressure field around aircraft12. It should be understood that while Applicants have provided examples of movable components and of their effects on the pressure field around an aircraft in flight, the examples included above are not exhaustive. Other components may also be movable and have an effect on the pressure field around the aircraft and may serve as movable components18and20.

Primary controller22and primary controller24may comprise any type of controller, processor, computer, or other arrangement of circuitry that is configured to issue commands to movable component18and movable component20, respectively, that cause movable component18and movable component20to move and/or to alter the manner in which said component is moving. It should be understood that reference herein to the movement of a movable component not only refers to the movement of a component that is currently stationary, but may also refer to the cessation of movement of a movable component that is currently moving and the alteration of the movement of a component that currently is moving (e.g., changing the rate of movement or changing the length or extent of such movement). In an example, movable component18may comprise a gas turbine engine or a component thereof (e.g., a compressor) and primary controller22may comprise a Full Authority Digital Electronic Controller (FADEC) that is configured to control operation of the gas turbine engine. In another example, movable component20may comprise a flight control surface (e.g., an aileron, a rudder, a flap, a slat, etc.) and primary controller24may comprise a Flight Control Computer (FCC) that is configured to control movement of the flight control surface. By positioning primary controllers22and24between controller28, on the one hand, and movable component18and20, respectively, on the other hand, primary controllers22and24retain full authority over movable components18and20. Arranged in this configuration, primary controllers22and24are able to evaluate whether to reject commands issued by controller28or whether to accept and transmit such commands to movable components18and20, as discussed in greater detail below. In other embodiments, controller28may be directly communicatively coupled to movable component18and movable component20.

Electronic data storage unit26may comprise any type of data storage component including, without limitation, non-volatile memory, disk drives, tape drives, and mass storage devices and may include any suitable software, algorithms and/or sub-routines that provide the data storage component with the capability to store, organize, and permit retrieval of data.

In the illustrated embodiment, electronic data storage unit26is configured to store a file30containing information indicative of and/or relating to the pressure fields that are anticipated to arise (hereafter, “anticipated pressure fields”) around aircraft12during flight. Such information may include, but is not limited to the pressure gradients that will be encountered in the anticipated pressure fields. This information may be gathered apriori in any suitable manner including, but not limited to, the use of appropriate computational fluid dynamics software, the collection and accumulation of data during testing under actual conditions, combinations thereof, and any other suitable means, whether now known or hereinafter invented and/or developed.

The information relating to the anticipated pressure fields stored in file30may correlate with different Mach speeds, different atmospheric conditions, different engine operating conditions, different aircraft states, and/or with other variables as well. For example, file30may contain a series of anticipated pressure fields, each one corresponding with a different Mach speed within a range of Mach speeds that aircraft12is anticipated to encounter. File30may also contain a series of anticipated pressure fields, each one corresponding with different atmospheric conditions that aircraft12is anticipated to encounter. File30, may also contain a series of anticipated pressure fields, each one corresponding with different operating conditions that aircraft12is anticipated to encounter. File30may also contain a series of anticipated pressure fields reflective of the pressure fields that are expected to develop around aircraft12as each of the Mach speed, the atmospheric conditions, and the operating conditions of aircraft12are varied in combination. In this manner, file30may contain anticipated pressure fields that correspond with substantially all combinations of Mach speed, atmospheric conditions, and operating conditions that aircraft12is anticipated to encounter.

Controller28is communicatively coupled with electronic data storage unit26. Through this communicative coupling, controller28has access to file30. Configured in this manner, controller28will have access to, and can select anticipated pressure fields that correspond with the atmospheric conditions, operating conditions, and Mach speed encountered by aircraft12and controller28may use those anticipated pressure fields as a basis for comparison with the pressure field detected by plurality14of pressure sensors16, as discussed in greater detail below.

Electronic data storage unit26may be further configured to store a file32containing information indicative of the effect that movable component18will have on the pressure field around aircraft12when it is moved. File32may also contain information indicative of the extent of that effect in correlation to the extent that movable component18is moved. File32may also contain information that correlates the effect of such movement on the pressure field, and the extent of the effect corresponding to the extent of the movement, with the various Mach speeds, operating conditions, and atmospheric conditions that aircraft12is anticipated to encounter. For example, file32may contain information indicative of how the movement and the extent of the movement of movable component18will affect the pressure field at the different Mach speeds that fall within the range of Mach speeds that aircraft12is anticipated to encounter. Similarly, file32may contain information indicative of how the movement, and the extent of the movement, of movable component18will affect the pressure field at different atmospheric conditions that fall within the range of atmospheric conditions that aircraft12is anticipated to encounter. Further, file32may contain information indicative of how the movement and the extent of the movement of movable component18will affect the pressure field at each of the different operating conditions that fall within the range of operating conditions that aircraft12is anticipated to encounter. File32may further contain information indicative of how the movement and the extent of the movement of movable component18will affect the pressure field in various circumstances where the Mach speed, the atmospheric conditions and the operating conditions all deviate in anticipated manners from the design conditions.

In embodiments having more than two or more movable components, electronic data storage unit26may be configured to store a plurality of files32, each containing information indicative of the effect that each additional movable component will have on the pressure filed around aircraft12as it is moved in the various conditions and operating states that aircraft12is anticipated to encounter. Configured in this manner, controller28will have access to a plurality of files32containing information that will allow controller28to determine which movable component or movable components should be moved to counteract or offset the propulsion system's effect on the pressure field around aircraft12and to what extent controller28should move said movable component(s).

In some embodiments, electronic data storage unit26may store a file34containing information indicative of the thresholds and/or limitations for the pressure field around aircraft12that are applicable to the different jurisdictions through which aircraft12may be flying. For example, electronic data storage unit26may contain a file34for each of the jurisdictions identified in a flight plan, for each jurisdiction that aircraft12has previously flown to or through, and/or for each jurisdiction throughout the world that has restrictions on the magnitude of a sonic boom generated by aircraft during supersonic flight. Configured in this manner, controller28will have access to file34, and therefore, will have access to information that will allow controller28to determine when corrective measures should be taken to offset the effect of the aircraft's propulsion system on the pressure field around aircraft12.

Controller28may be any type of computer, controller, micro-controller, circuitry, chipset, computer system, or microprocessor that is configured to perform algorithms, to execute software applications, to execute sub-routines and/or to be loaded with and to execute any other type of computer program. Controller28may comprise a single processor or a plurality of processors acting in concert. In some embodiments, controller28may be dedicated for use exclusively with system10while in other embodiments controller28may be shared with other systems on board aircraft12.

In the illustrated embodiment, controller28is communicatively coupled with plurality14of pressure sensors16, with primary controllers22and24, and with electronic data storage unit26. Controller28is communicatively connected to movable components18and20through primary controllers22and24. These communicative couplings/connections may be accomplished through the use of any suitable means of transmission including both wired and wireless connections. For example, each component may be physically connected to controller28via a coaxial cable or via any other type of wire connection that is effective to convey signals. In other embodiments, each component may be communicatively connected to controller28across a communication bus. In still other examples, each component may be wirelessly connected to controller28via a BLUETOOTH connection, a WIFI connection or the like.

Being communicatively coupled and/or connected with each of the components identified above provides a pathway for the transmission of commands, instructions, interrogations and other signals between controller28and each of the other components. The plurality14of pressure sensors16, the primary controllers22and24, and the electronic data storage unit26are each configured to interface and engage with controller28. For example, pressure sensors16are each configured to provide information to controller28indicative of their respective pressure readings and controller28is configured to receive such pressure readings. Primary controllers22and24are each configured to send and receive communications and/or instructions from controller28and controller28is configured to send and receive communications from primary controllers22and24. Electronic data storage unit26is configured to receive communications, interrogations, and instructions from, and to provide information to, controller28and controller28is configured to send communications, interrogations, and instructions to, and to receive information from, electronic data storage unit26. In embodiments where controller28is directly communicatively coupled with movable components18and20, movable components18and20are configured to receive and respond to communications, instructions, and commands issued by controller28and controller28is configured to communicate with, and to issue instructions to movable components18and20and to receive communications from movable components18and20.

Controller28is configured to interact with, coordinate and/or orchestrate the activities of each of the other components of system10for the purpose of controlling the pressure field that forms around aircraft12in flight. In a non-limiting example, controller28is configured to receive pressure readings from each pressure sensor16. In an embodiment, controller28will be programed with, or will otherwise have access to information indicative of where each pressure sensor16is located with respect to an exterior surface of aircraft12. Using the location information and the pressure readings provided by each pressure sensor16, controller28is configured to calculate the pressure field around aircraft12. In an embodiment, controller28will have access to information indicative of the prevailing atmospheric conditions, the current Mach speed of aircraft12, and the current operating conditions of aircraft12. Controller28may obtain this information by communicating with other systems onboard aircraft12including, but not limited to, wireless transmitters, instrument panel gages, flight control computers, and the like.

Using the current Mach speed and the current operating conditions of aircraft12, and using the prevailing atmospheric conditions in the vicinity of aircraft12, controller28is configured to communicate with electronic data storage unit26to obtain an anticipated pressure field that corresponds with the Mach speed of aircraft12, the current operating conditions of aircraft12, and the prevailing atmospheric conditions encountered by, or in the vicinity of, aircraft12. Controller28is further configured to compare the anticipated pressure field obtained from electronic data storage unit26with the pressure field that it has calculated from the pressure readings provided by plurality14of pressure sensors16. As part of the comparison, controller28may be programmed to identify deviations between the pressure gradients predicted in the anticipated pressure field with the pressure gradients that controller28detects during its calculation of the pressure field. In other embodiments, controller28may be configured to use any suitable metric, either in addition to, or instead of, the anticipated pressure gradients and the detected pressure gradients when comparing the anticipated pressure field with the pressure field calculated by controller28. In instances where a deviation is detected that does not coincide with the movement of a movable component, the deviation may be caused by the interaction between the propulsion system of aircraft12and the free stream of air flowing over aircraft12.

In some embodiments, controller28may be configured to automatically take corrective measures when it detects the occurrence of any deviation between the anticipated pressure field and the pressure field that controller28calculates. In other embodiments, controller28may be configured to assess the deviation and only take corrective measures when the deviation exceeds a predetermined magnitude or threshold. In some examples, that predetermined magnitude may be programmed directly into controller28. In other examples, controller28may be configured to obtain information from electronic data storage unit26that is indicative of acceptable deviations between the pressure field and the anticipated pressure field. In some embodiments, controller28may access file32to obtain this information. In some examples, such information may correspond with the jurisdiction that aircraft12is flying over.

Once controller28has determined that the deviation between the pressure field and the anticipated pressure field requires corrective measures, controller28is configured to obtain information relating to movable components18and20. This information relates to the effect that movement of each movable component will have on the pressure field. In some embodiments, controller28will access file32to obtain this information. In other embodiments, such information may be programmed into controller28or be available from some other source accessible to controller28. Using this information, controller28can determine which component to move and to what extent it should be moved in order to reduce the deviation between the anticipated pressure field and the pressure field that controller28has calculated.

For example, controller28may obtain information indicative of the effects on the pressure field of changing the engine cycle of the gas turbine engine of the propulsion system while flying at the current Mach speed, operating conditions, and prevailing atmospheric conditions. Controller28may also obtain information about the effects on the pressure field of moving the propulsion system's compression surface fore or aft while flying at the current Mach speed, operating conditions, and prevailing atmospheric conditions. Controller28may also obtain information about the effects on the pressure field of deflecting the ailerons of aircraft12up or down while flying at the current Mach speed, operating conditions, and prevailing atmospheric conditions. Controller28may obtain similar information relating to all movable components of system10.

Using this information, controller28can determine which movable component to move in order to most advantageously reduce or entirely offset the deviation that controller28detected between the pressure field and the anticipated pressure field. Controller28may use other information as well when making this determination. For example, and without limitation, controller28may also take into consideration the effect on drag, the effect on the speed, the effect on fuel consumption, and any other suitable factor that may be impacted by movement of the movable component. For example, moving a control surface may have an undesirable effect on the angle of attack of aircraft12while changing the engine cycle may have an undesirable effect on the Mach speed of aircraft12. Controller28may be programmed to prioritize the desirability or undesirability of effects such as these and may determine which movable component to move based on which movement will have the least undesirable effect.

Once controller28has determined which movable component to move, controller28is configured to transmit an instruction to the primary controller associated with that component. In an example where controller28has determined that movable component18should be moved and has further determined to what extent it should be moved, controller28is configured to send an instruction to primary controller22to move movable component18in the manner, and to the extent, determined by controller28.

In some embodiments, primary controller22will comply with the instruction provided by controller28and will command movable component18to move in the manner determined by controller28. In other embodiments, primary controller22will be configured to evaluate the command provided by controller28for compatibility with restrictions and limitations that govern the control that primary controller22exercises over movable component18. If the command is found to be compatible with the restrictions and limitations programmed into primary controller22, then primary controller22will send the command to movable component18. However, in instances where the movement commanded by controller28is not compatible with the restrictions and limitations programmed into primary controller22, primary controller22will not comply with the command. In instances where the command is only partially compatible with the restrictions and limitations programmed into primary controller22, primary controller22will modify the command to provide partial compliance. In instances where primary controller22fully complies with the command, primary controller22may be configured to send a message to controller28communicating its compliance with the command. In instances where primary controller22determines that compliance with the command is not appropriate, primary controller22may be configured to ignore the command and communicate its rejection of the command to controller28. Similarly, in instances where primary controller22determines that only partial compliance with the command is appropriate, primary controller22may communicate its partial compliance to controller28.

After controller28has provided the command to primary controller22, controller28will continue to monitor the pressure field around aircraft12and compare it with the anticipated pressure field. If the deviation between the pressure field and the anticipated pressure field dissipates, then no further action by controller28may be needed. In instances where the deviation does not diminish or does not diminish sufficiently, or in instance where controller28receives a communication from primary controller22indicative of non-compliance or of only partial compliance, controller28may be configured to engage in further analysis to determine if alternate or further corrective measures are appropriate. In some instances, when the deviation does not sufficiently diminish, controller28may modify the original command to obtain further movement of movable component18. In other instances, controller28may determine that movement of movable component20may be necessary. In still other instances, such as when controller28receives a communication from primary controller22that compliance with the command will not be forthcoming or that only partial compliance will be provided, then controller28may provide a command to primary controller24seeking movement of movable component20. Primary controller24may be configured to either comply with the command or to engage in an analysis to determine whether the command is compatible with restrictions and limitations programmed into primary controller24. After engaging in the analysis, primary controller24may fully comply with the command issued by controller28or it may only partially comply with the command or it may reject the command altogether. Primary controller24may be further configured to send a message to controller28indicative of its full compliance, partial compliance, or non-compliance, as appropriate.

After issuing the command, controller28will further monitor the pressure field to determine whether the deviation dissipates or sufficiently diminishes. If so, then controller28will take no further action other than to continue its monitoring of the pressure field. If the deviation does not dissipate, the analysis described above will repeat and controller28will determine how and whether to take action to reduce the deviation. In some embodiments, the above described sampling, analysis, determination, issuance of commands, compliance with commands, and further monitoring of the pressure field around aircraft12may be performed automatically by system10without aircrew intervention, involvement, and/or awareness.

FIGS. 2-6depict aircraft12equipped with system10(seeFIG. 1) during flight operations and further depict the stages of monitoring a pressure field36around aircraft12, determining the existence of a deviation between pressure field36and the anticipated pressure field, and the corrective measures implemented by system10. In the embodiments illustrated inFIGS. 2-6, pressure field36has been illustrated through the use of multiple double headed arrows situated around aircraft12.

With respect toFIG. 2, aircraft12is equipped with a propulsion system38comprising a gas turbine engine (not shown), an inlet40and a nozzle42. Inlet40includes an extendable compression surface44configured for movement between a retracted position and an extended position. Extendable compression surface44is illustrated inFIG. 2in its retracted position.

Aircraft12further includes a plurality of pressure sensors16to detect and measure pressure field36. In the illustrated embodiment, aircraft12is configured with a large number of pressure sensors16arranged in a substantially equidistant pattern along substantially an entire length of the exterior of aircraft12. For ease of illustration, only small portion of the pressure sensors have been identified with the reference numeral16. In other embodiments, pressure sensors16may be arranged in any other suitable manner. For example, in other embodiments, pressure sensors16may be concentrated in areas where interaction between propulsion system38and pressure field36is known to occur. In still other embodiments, pressure sensors16may be disposed only in areas where interaction between the propulsion system and the pressure field are known to occur.

In the embodiment illustrated inFIG. 2, several pressure sensors16have been circled and identified with reference letters. These pressure sensors16have been arranged in locations where adverse interaction between propulsion system38and pressure field36are anticipated. For example, the pressure sensors16identified with the reference letter A are disposed in a region proximate inlet40. The pressure sensors16identified with the references letter B are disposed in a region where a shock formed by the cowl lip of the propulsion system's nacelle is expected to intersect with the surface of aircraft12. The pressure sensors16identified with the reference letter C are disposed in a region proximate nozzle42. Arranged in this manner, any substantial change in pressure from one pressure sensor16to another pressure sensor16proximate propulsion system38will be detected.

With continuing reference toFIGS. 1-2,FIG. 3depicts a condition where a steep pressure gradient has formed proximate inlet40. The steep pressure gradient is depicted through the use of elongated double headed arrows46,48, and50, which are representative of elevated static pressure detected by pressure sensors16in the vicinity of inlet40. Controller28will receive information indicative of this steep pressure gradient from pressure sensors16in the region identified with the reference letter A illustrated inFIG. 2. In the illustrated embodiment, controller28will determine that this steep pressure gradient is inconsistent with the pressure gradient of an anticipated pressure field associated with the current Mach speed, prevailing atmospheric conditions, and current operating conditions of aircraft12. Controller28may make this determination by accessing file30stored in electronic data storage unit26. In some embodiments, controller28may evaluate whether the inconsistency between the detected pressure gradient and the anticipated pressure gradient exceeds a predetermined threshold in order to determine whether corrective measures are needed. Controller28may make this determination by accessing file34stored in electronic data storage unit26. In the illustrated embodiment, controller28determines that corrective measures are needed.

With respect toFIG. 4, and with continuing reference toFIGS. 1-3, controller28has sent a command to the primary controller associated with extendable compression surface44instructing the primary controller to extend extendable compression surface44by an amount determined by controller28to be necessary to offset the steep pressure gradient. Controller28may have determined which movable component to move and the amount of movement needed to diminish the deviation between the pressure field and the anticipated pressure field by accessing file32in electronic data storage unit26. In the scenario illustrated inFIG. 4, the primary controller associated with extendable compression surface44has determined that the command given by controller28is compatible with the limitations and restrictions that govern the primary controller and has forwarded the command to move to extendable compression surface44. As a result, extendable compression surface44has moved in the direction indicated by arrow52to an extended position. Because of this movement of extendable compression surface44, the steep pressure gradient detected inFIG. 3has diminished as indicated by the diminution of arrows46,48, and50inFIG. 4. As a result, the deviation between pressure field36and the anticipated pressure field has diminished and pressure field36has returned to a pressure field that will not give rise to a sonic boom that will exceed applicable restrictions.

An alternate scenario is illustrated inFIGS. 5 and 6. With continuing reference toFIGS. 1-4, inFIG. 5, extendable compression surface44has been moved to the extended position illustrated inFIG. 4, but the steep pressure gradient illustrated by arrows46,48, and50has not diminished to an acceptable level. Through continued monitoring of pressure field36, controller28detects the continued existence of a steep pressure gradient and determines that further action is needed.

InFIG. 6, controller28determines that an appropriate action to further reduce the steep pressure gradient would be to move aileron54. Controller28may have made this determination by accessing file32in electronic data storage unit26. Controller28sends a command to the primary controller associated with aileron54requesting that aileron54be deflected in a downward direction to a specified angle.

In the scenario illustrated inFIG. 6, the primary controller associated with aileron54has determined that the command given by controller28is compatible with the limitations and restrictions that govern the primary controller and has forwarded the deflection command to aileron54. As a result, aileron54has deflected downward in the manner illustrated inFIG. 6. This movement of aileron54, in combination with the movement of extendable compression surface44causes the steep pressure gradient detected inFIG. 5to diminish as indicated by the diminution of arrows46,48, and50. As a result, the deviation between pressure field36and the anticipated pressure field has diminished and pressure field36has returned to a pressure field that will not give rise to a sonic boom that will exceed applicable restrictions.

FIG. 7illustrates a non-limiting embodiment of a method60for controlling a pressure field around an aircraft.

At step62, a pressure field around an aircraft is measured using a plurality of pressure sensors. In some embodiments, the plurality of pressure sensors may be arranged along an exterior surface of the aircraft where they can directly sample the free stream of air flowing over the aircraft's surface. In other embodiments, the pressure sensors may be located inside of the aircraft and may use optical means to take pressure measurements. The pressure sensors may be arranged in any suitable manner including, but not limited to, a substantially even distribution along the airframe or a concentrated arrangement in regions of the aircraft known or expected to experience steep pressure gradients.

At step64, a controller on board the aircraft receives information from each of the pressure sensors indicative of the pressure readings taken by the pressure sensors.

At step66, the controller determines when the pressure field deviates from a desired pressure field based, at least in part, on the information received from the plurality of pressure sensors. The controller may also utilize information pertaining to the aircraft's Mach speed, the prevailing atmospheric conditions, and the operating conditions of the aircraft. The controller may also use information stored in an electronic data storage unit indicative of an anticipated pressure field. In some embodiments of method60, the controller may also determine whether corrective measures are needed to reduce the deviation.

At step68, the controller transmits an instruction to a movable component onboard the aircraft to move in a specified manner that is anticipated to cause a reduction in the deviation between the pressure field and the anticipated pressure field. In some embodiments, the controller may transmit the command to an intermediate primary controller that is configured to control movement of the movable component. In some embodiments, further monitoring by the controller may occur followed by the transmission of further commands to move the movable component further or to move other movable components on board the aircraft. This step may be repeated until the deviation diminishes completely or diminishes to a level below a predetermined threshold.