Abstract: A method for characterizing pressure sensors to improve accuracy in an air data system is described where the sensors include at least one static pressure sensor and at least one total pressure sensor. The method includes characterizing the static pressure sensor and the total pressure sensor to determine a static pressure sensor error, Pse, and a total pressure sensor error, Pte, and performing a second ratiometric characterization to reference the total pressure sensor error, Pte, to the static pressure sensor error, Pse.

Abstract: An air data system and method for a rotary aircraft is described. The air data system includes a plurality of flush ports connected via tubing to a plurality of air flow sensors that can measure air flow speeds as low as approximately 0.02 knots. The flush ports are arranged around a main rotor shaft and below a rotor hub of the rotary aircraft to help reduce the impact of rotor downwash. The flush ports and tubing permit air to flow into the air flow sensors, which allows the plurality of air flow sensors to measure speed and direction of cross-wind components of air flow surrounding the rotary aircraft.

Abstract: The invention relates to a device for ensuring safe movement of a moving part. The movement of the moving part is guided along or about an axis (4; 42) and is limited by at least one stop (1; 20; 51). The device comprises means for recording the exceeding of a nominal force by a force exerted on the stop (1; 20; 51) by the moving part along or about the axis (4; 42). The invention is particularly applicable to angle-of-attack sensors used in aeronautics.

Abstract: The invention relates to a multifunction probe for aircraft. The probe has a mobile vane intended to align with the axis of an air flow around the probe. The mobile vane comprises first pressure pickup means for measuring the total pressure of the flow and second pressure pickup means for measuring the static pressure of the flow. The mobile vane furthermore has a profile whose flexure is variable.

Abstract: A method of estimating the airspeed of an aircraft during low airspeed conditions includes measuring a negative impact pressure using a pitot-static probe on the aircraft. Then, the method includes estimating a non-zero airspeed of the aircraft as a function of the measured negative impact pressure.

Abstract: A multi-function air data sensing probe has a strut that is mounted on an aircraft and extends laterally from the aircraft skin. The strut is supported on a base plate, and has a pitot pressure sensing tube at the outer end thereof, with a pitot port facing upstream, and also includes a passageway for total air temperature sensor including a forwardly facing inlet scoop that leads to a chamber in the strut that is laterally offset from the inlet scoop so that flow changes direction as it enters the chamber. The surface defining the change of direction between the scoop and the chamber is provided with bleed holes for bleeding off boundary layer air. A vane type air data sensor is mounted on a shaft that rotates freely and is supported on the strut, and is positioned to sense the relative air flow past the strut to determine changes of relative angles of such air flow. In addition, the strut has static pressure sensing ports on lateral sides thereof leading to a separate chamber on the interior of the strut.

Abstract: The present invention provides a method for determining information for an air vehicle including the steps of providing a first coefficient of pressure data point, providing a situation involving the air vehicle, deriving pressures during the situation and deriving a second coefficient of pressure data point from the pressures derived during the situation, and defining a line passing through the first and second coefficient of pressure data points, whereby a selected coefficient of pressure data point on the line corresponds to the information. The invention encompasses apparatus for accomplishing the method. In some embodiments, the information relates to angles from zero lift and/or zero yaw.

Abstract: A multi-function probe system that provides redundancy for measurements and compensates for effects of sideslip of an aircraft includes at least two probes that are symmetrically located on the opposite sides of the aircraft, and a third probe mounted on the centerline of the aircraft positioned to directly measure local sideslip with ports that are positioned on opposite sides of the center plane of the aircraft. Each of the probes includes self contained instrumentation for providing signals indicating various pressures. The local angle of sideslip sensed by the third probe is used as a compensation for pressure readings at either of the other probes for determining actual angle of attack, and static pressure.

Abstract: In an iterative method of determining aircraft flight data parameters using first and second multi-function probes, an assumed value of a first aircraft parameter is defined to be equal to an initial value. Using the assumed value of the first aircraft parameter together with the respective local angles of attack determined at first and second multi-function probes, first and second estimates of a second aircraft parameter are calculated and compared. If the first and second estimates of the second aircraft parameter are within tolerance of each other, then the first aircraft parameter is approximately equal to the assumed value, and the second aircraft parameter is determined from the first and second estimates. If the first and second estimates of the second aircraft parameter are not within tolerance of each other, then an iterative process is continued to correctly determine the first and second parameters.

Abstract: An angle of attack sensor has a vane mounted on a rotating shaft that rotates in response to angle of attack. The shaft has a rotor at one end which is in a chamber in a housing supporting the shaft. The chamber includes a space around the rotor filled with either an electrorheological or magnetorheological fluid. A controller is used to provide an electrical signal, such as a signal controlling an electromagnet, to change the magnetic field affecting the fluid in response to various aircraft parameters to thereby control the viscosity of the electrorheological or magnetorheological fluid in the chamber and control the amount of damping of the rotating vane.

Abstract: A method of the invention allows the determination of aircraft sideslip using an air data probe and an inertial reference unit. A lateral sideslip component &bgr;L of the aircraft is calculated as a function of inertial flight information. An angular sideslip component &bgr;A of the aircraft is also calculated as a function of inertial flight information. The lateral sideslip component &bgr;L and the angular sideslip component &bgr;A are combined to obtain a total sideslip angle &bgr;TOTAL for the aircraft. The total sideslip angle &bgr;TOTAL can be used to compensate static pressure, angle of attack and other aircraft parameters for sideslip effects.

Abstract: A method of the invention allows the determination of aircraft sideslip using an air data probe and an inertial reference unit. A lateral sideslip component &bgr;L of the aircraft is calculated as a function of inertial flight information. An angular sideslip component &bgr;A of the aircraft is also calculated as a function of inertial flight information. The lateral sideslip component &bgr;L and the angular sideslip component &bgr;A are combined to obtain a total sideslip angle &bgr;TOTAL for the aircraft. The total sideslip angle &bgr;TOTAL can be used to compensate static pressure, angle of attack and other aircraft parameters for sideslip effects.

Abstract: A fixed multifunction probe, e.g., for aircraft and configured to measure air flow parameters near an airplane. The probe includes a body closed by a rounded cap, at least three pressure taps situated at specified positions of the body, a pressure measurement mechanism for measuring at least as many pressures as pressure taps, and a calculation device for calculating the air flow parameters.

Abstract: The present invention provides a flight instrument apparatus and method for its use in air vehicles having an indicator visibly displaying angles from zero lift and having a data port for electrically exporting angles from zero lift wherein pressures from wing ports and pressures from the pitot and static ports of air vehicles are sensed, converted to digital data and mathematically divided one into the other to give a coefficient of pressure which varies uniquely with angles from zero lift of the air vehicle and which is used to calculate the angular deviation from angle of zero lift using a known relationship between the coefficient of pressure and the angular deviation from angle of zero lift.

Abstract: Aircraft probe assemblies integrally include a total airstream temperature sensor. Preferred embodiments include at least one pressure sensing port and a temperature sensing port which are in fluid communication with a pressure sensing chamber and a temperature sensing chamber, respectively. A temperature sensor may thus be disposed in the temperature sensing chamber so as to sense the temperature of the in-flight air flow. The temperature sensor is most preferably shielded thermally from the probe element. Specifically, the temperature sensor is most preferably coaxially surrounded by a generally cylindrical thermal shield structure having airflow inlet and outlet apertures. The thermal shield thereby prevents the temperature of the probe element (which may be heated by an integral electrical resistance heater during potential in-flight icing conditions) from affecting the airflow temperature data obtained by the temperature sensor.

Abstract: Improved multifunction probe designs include circumferentially separated pairs of sensing ports which may respectively be dedicated to angle of attack functionality and air data pressure sensing functionality. In one preferred embodiment, a multifunction aircraft probe is provided with a rotatable probe element which is adapted to project outwardly from an aircraft with which it is operatively mated. The probe element is provided with a centrally located (i.e., in substantial alignment with the probe's stagnation line) dynamic pressure sensing port, and outer and inner pairs of pneumatic sensing ports which are symmetrically circumferentially separated from one another and from the dynamic pressure sensing port. Most preferably, each of the outer pneumatic sensing ports is circumferentially spaced from the central dynamic pressure sensing port by a first angle (e.g., substantially 90.degree.

Abstract: An apparatus and method for measuring airflow past an aircraft by extending a probe (14) from the aircraft into the airflow with a retraction-extension mechanism (20) when a measurement is desired, and retracting the probe (14) when a measurement is not desired. In a low observable aircraft (12), the probe (14) can extend to measure angle of sideslip for flight in a slow speed regime, such as is experienced in vertical take-offs and landings, and can retract during normal wing borne flight to reduce the aircraft's radar signature.

Abstract: A process and algorithms to determine and correct for the error in azimuth alignment and the errors in "North" and "East" Gyro Drift Rates in an inertial navigator which has been aligned via gyrocompassing, or via the "Stored Heading" technique, with the system "at rest". The process and algorithms may be implemented as an automatic sequence within the system computer to determine and correct the system errors thus determined. These actions make the inertial navigator more accurately represented by the model of an ideal navigation system with a pure and singular initial azimuth misalignment error. Thus the inertial navigator's inital azimuth misalignment error can be more accurately determined and corrected by the model.

Abstract: An orientation monitoring apparatus includes an inner spherical shell rigidly fixed within an outer spherical shell, and a spherical ball positioned between the two shells. The inner shell has a polar coordinate grid impressed on it so that the position of the ball relative to the grid is seen from above. An inertial platform is rotationally interfaced with the inner shell. This platform supports a video camera with a view of the grid and ball. As well, the platform supports a motor driven fly-wheel which keeps the platform in a desired horizontal attitude. The motor, camera and a computer are driven by a solar cell and storage battery also mounted onto the platform and which receives energy through the transparent shells. An optical recognition software driven by the computer, is used to automatically compute the movements of the ball relative to the grid so that rotational movements of the shells can be computed in three-space.

Abstract: An air data sensing system utilizes a plurality of probes, each probe having three pressure sensing ports, and each assembled with a sensor package that minimizes the need for corrections due to temperature or other variations in ambient conditions. The system is mounted on an air vehicle using two or three sets of right and left pairs of probes. The probes of each set are vertically spaced from the probes of the other sets. The probes are made light weight and small. In the arrangement shown the probes provide triple redundancy and because of the orientation on the air vehicle provide all needed pressure and angle information, including the angle of sideslip.

Abstract: An air data sensor strut made of a single block of material has one side finished in a smooth contour, and has grooves in an opposite side of the strut for receiving pressure carrying conduits or other elongated members such as a heater. The heater and conduits are secured in place with a filling of potting material and the open sides of the grooves are finished after filling so that the desired contour is provided for the opposite side of the strut. The strut has a thin cross-section because of the elimination of hollow interior spaces formed by spaced walls.

Abstract: A rotatable airstream direction probe is additionally provided with a dynamic pressure sensing port positioned substantially midway between a pair of pneumatic sensing ports with respect to the probe's stagnation line. Pneumatic output ports may thus be provided, each of which communicates with a respective one of the pneumatic sensing and dynamic sensing ports in the probe. The pressure outputs from such output ports may thus be indicative of static and dynamic pressure of an airstream so as to be capable of determining flight information of an aircraft such as airspeed, altitude and vertical speed.

Abstract: An improved microprocessor-based navigational aid system for use onboard a vessel is disclosed. The system includes a microprocessor having peripheral memory devices, sensors for measuring variable parameters and thumb switches for inserting known values for fixed parameters. The microprocessor computes from these parameters, data which enable the optimum navigation of a vessel. In determining these data, the computation includes such factors as leeway and current set and drift, which are determined electronically. The system includes components for receiving information regarding the vessel's present position from a satellite-based external information source. That information is relayed to the microprocessor which uses it to periodically correct the positional information stored in the peripheral memory device.

Abstract: A vane-type forward fuselage mounted angle of attack sensor having an internal force relief feature is disclosed. The sensor includes a cam surface having a first portion which defines a segment of a circle, a second portion which defines a curve with a decreasing radius and a shoulder portion between the first and second portions. A cam follower and spring biasing member act as a stop to limit the angular displacement of the vane and as an override to protect the vane against breakage and to automatically return the vane to an operational position after an override.

Abstract: The present invention relates to an incidence probe, in particular for an aircraft, comprising at least two pressure inlets. To this end, it comprises a least one flowmeter (1) and a pneumatic restriction (4) arranged in series between two pressure inlets.

Abstract: An aerodynamic vane is mounted on the fuselage of an aircraft for purposes such as sensing the angle of attack of an aircraft. The vane is attached to a fuselage mounting hub by means of a deformable hinge member and a weakened linear portion of the vane which is designed to give way under the force of impact of an object striking the vane. Should an object such as a bird strike the vane, the vane will separate from the hub along the weakened linear portion without the main body of the vane shattering. The hinge member, while it will deform under the impact, retains the vane to the fuselage so that it cannot fly into the engine or otherwise cause damage to the aircraft.

Abstract: A sensor has a sensing region that responds to a surface property by producing an output signal. The sensor has a spatially distributed shape or sensitivity so that the output decreases away from a central part of the sensor, and thus the outputs of plural sensors combined have finite spatial transform as well as high roll off in spatial frequency. Preferably the output decreases to zero at edges of the sensor, and conditions of continuity or vanishing may be imposed on first or higher order derivatives. An edge sensor suitable for mounting at the edge of the structure has its weight function obtained by processes of reflecting and inverting the weight function at an edge. A sensor system employs plural such sensors and edge sensors to produce bounded spatial transfer functions for characterizing the structure. Embodiments of piezeoelectric, resistive, capacitive and thermal sensors are described.

Abstract: An apparatus senses a free stream flow parameter using airflow adjacent an air vehicle. The apparatus includes a first sensor sensing a longitudinal axial component and a lateral axial component of a parameter of local airflow immediately adjacent the first sensor. A second sensor senses a longitudinal axial component and a second axial component perpendicular to the lateral axial component sensed by the first sensor of a parameter of local airflow immediately adjacent the second sensor. The first and second sensors are mounted on the air vehicle such that a longitudinal axis of the first sensor lies in a first plane including a longitudinal axis and a longitudinal axis of the second sensor means lies in a second plane substantially perpendicular to the first plane and including the longitudinal axis of the first plane. A correction unit obtains a signal representing the free stream flow parameter as a function of the parameter components sensed by the first and second sensors.

Abstract: An apparatus detects an air turbulence and wind shear encountered by an air vehicle having an accelerometer sensing air vehicle vertical acceleration. The apparatus includes a pressure sensor having a pressure sensing port for sensing a pressure parameter of a local air flow which changes with changes in the local airflow turbulence, and a fast time constant pressure transducer coupled to the pressure port for generating a transducer signal representative of the parameter. Differentiating means calculates a time derivative of the transducer signal and provides a turbulence signal representative of the time derivative. Subtracter means provides the difference between the turbulence signal and a vertical acceleration signal from the accelerometer, to provide a wind shear indicating signal indicative of an increase in air turbulence.

Abstract: A system for correcting errors in static pressure, airspeed or airspeed rate caused by maneuvering that causes variations in static air pressure measurements compares a barometrically derived vertical velocity or altitude signal with an inertially-derived vertical velocity or altitude signal to provide a correction signal that is representative of changes in static air pressure and is used to correct the static pressure, airspeed or airspeed rate signal.

Abstract: The present invention relates to a air data sensing probe that has a cylindrical barrel joined to a contoured strut section. The strut has leading and trailing edges formed along curved paths, and supports the cylindrical barrel at a position spaced from a mounting surface and facing upstream of relative air movement. The strut has a rounded leading edge, and is generally ogival-shaped in cross-section. There is a blended, relatively quickly-changing transition section to blend the trailing end of the cylindrical barrel into the ogival-shaped strut section so that the probe has reduced weight of the strut and drag, and through reduction of the cross-sectional area and rounding the strut leading edge, has enhanced anti-icing performance.

Abstract: An air data sensor (10) for mounting on an air vehicle (14), the outer end (11) is spaced outwardly from a surface of the air vehicle (14), a mounting base (12) and an outer end (11) which is provided with sensing ports (21, 22) for sensing air data parameters, the body (32) of the sensor (10) is made so that when viewed in the bisecting plane of the body (32), the inner and outer edges (34, 36) of the body curve continuously from the outer end (11) to the base (12). These edges (34, 36) diverge from adjacent to the outer end (11) to the base (12) to provide a very smooth streamlined probe (10) which tends to reduce drag.

Abstract: An instrumentation system for measuring airspeed and angle-of-attack (AOA) is provided. The system includes a sensor assembly, a constant voltage anemometer, a microprocessor assembly with software, and an output device suitable for powering conventional cockpit display or for powering other speed AOA devices such as engine inlets and stability augmenters. The sensor assembly is a pair of orthogonal miniature cylinders with embedded micro-thin multielement hot film sensors. Operation of the sensor assembly by the constant voltage anemometer provides detection of cylinder leading edge flow stagnation point and oscillatory frequency. The stagnation point determination provides angle-of-attack data; the oscillatory flow frequency provides data to calculate cylinder shed-vortex frequency which is converted to airspeed data. The sensor assembly is solid-state, having no ports, diaphragms or moving parts and is heated in normal operation.

Abstract: An airplane stall alarm testing tool applies a temporary partial vacuum to a stall horn installed in an aircraft wing. The tool mechanically or otherwise creates a vacuum without human direct oral contact with the aircraft and enables testing by a pilot unable to reach the horn.

Abstract: The probe comprises a wind vane (1) mounted for rotation on the aircraft in order to orient itself in the direction of the flow and provided with a detector (15) for detection of differential pressure representative of the aerodynamic angle of incidence of the wind vane, and a device for determining the orientation of the wind vane with respect to the aircraft. The probe comprises a control loop (14) adapted to cancel out the aerodynamic angle of incidence of the wind vane and controlled by the detector (15). The probe supplies the true angle of incidence of the aircraft directly.

Abstract: A method and apparatus for directly measuring the time-averaged streamwise momentum in a turbulent stream use a probe which has total head response which varies as the cosine-squared of the angle of incidence. The probe has a nose with a slight indentation on its front face for providing the desired response. The method of making the probe incorporates unique design features. Another probe may be positioned in a side-by-side relationship to the first probe to provide a direct measurement of the total pressure. The difference between the two pressures yields the sum of the squares of the cross-stream components of the turbulence level.

Abstract: A method and portable microcomputer-based system for determining flow field stagnation points are disclosed. The apparatus uses hot film sensors wrapped around the leading edge of an airfoil to measure boundary layer oscillations. A plurality of sensor signals are provided which may be selected in groups. Signals from sensors in any group are read simultaneously. The signals are then converted to digital form and displayed on the video display of a microcomputer. Points of airflow stagnation are characterized by a doubling in frequency or other discrete harmonics and by a reversing of the phase of oscillations. Those points are identified by displaying and comparing signals from different sensor locations on a video display.

Abstract: An angle of attack sensor is provided with ports for sensing flow angles in desired planes based upon differential pressure at the ports when a longitudinal or reference axis of the sensor changes relative to the flow stream. Impact pressure is also measured with the same probe, or with a separate probe, and the angle of attack is calculated by subtracting the pressures at the angle sensitive ports, and dividing by the measured impact pressure (q.sub.cm). At higher angles of attack, the denominator q.sub.cm approaches and passes through zero. When this quantity, q.sub.cm, approaches zero, the angle of attack signal becomes undefined. The problems encountered as q.sub.cm approaches zero has been a limitation of useful angle of attack range of angle of attack sensors for many years. It has been discovered that if the angle of attack ratio, where q.sub.cm is the denominator, is inverted at some point when the denominator q.sub.

Abstract: Methods and compositions for measuring the pressure of an oxygen-containing gas on an aerodynamic surface, by oxygen-quenching of luminescence of molecular sensors is disclosed. Objects are coated with luminescent films containing a first sensor and at least one of two additional sensors, each of the sensors having luminescences that have different dependencies on temperature and oxygen pressure. Methods and compositions are also provided for improving pressure measurements (qualitative or quantitive) on surfaces coated with a film having one or more types of sensor.

Abstract: A method and apparatus for sensing wave flow across a surface wherein at least two pressure levels are sensed and combined to provide a representation of waves within the flow. In the preferred embodiment holes bored through the aircraft surface at an interval of one-half the wavelength of the flow being measured introduce pressure perturbations into a cavity so they may acoustically interfere. The interfering waveform is sensed by at least one microphone disposed in the cavity.

Abstract: A preassembled air data sensor probe and air data transducer assembly has permanently connected flexible tubing coupling the air data transducer fittings and the sensor fittings. The flexible tubing permits the air data sensor and air data transducer to be installed into an air vehicle after having been preassembled and pretested for leaks at the factory. The permanently attached assembly avoids the need for calibration or pressure checks after installation on the aircraft. The preassembled flexible tubing permits manipulation of the transducer to mount it into the proper location even in tight quarters. The flexible tubing can have a section that acts as a drain trap for accumulating ingested water.

Abstract: A method and apparatus are disclosed for detecting the nature of fluid flow. Specifically, an omnidirectional aerodynamic sensor is disclosed comprising an omnidirectional aerodynamic drag force inducing probe, a force transducer and a signal processor. The force transducer is illustratively an array of strain gauges which detect forces in each of three orthogonal directions. Such forces are initially detected by the probe and then transmitted to the transducer. The transducer outputs electrical signals which the signal processor processes in order to determine, for example, aircraft angle-of-attack and angle-of-sideslip as well as wind speed and direction. The invention is especially useful in the field of aviation.

Abstract: A sensor for measuring the relative velocity of an oncoming medium includes a tubular and preferably radially symmetrical sensor body having a leading front end, and a wall with an inner surface defining an axial hollow space being open to the outside at the leading front end. The sensor body includes a preferably streamlined sensor head portion associated with the front end, and a remainder of the sensor body forming a sensor shaft. The wall has at least one conduit being radial or having a radial component. The at least one conduit is separated from the axial hollow space and spaced apart from the front end. The at least one conduit is open to the outside from one of the portions. A method of measuring the relative velocity of the medium includes detecting a first measured value representing the sum of the static pressure and the velocity-dependent dynamic pressure of the medium with an axial pitostatic tube discharging at the front end of a sensor body.

Abstract: An audible indicator is arranged in combination with an electronic stall indicator, wherein the audible device includes a conical entrance and exit tube coaxially aligned with a central cylindrical tube, with a whistle member positioned within the tube, with the whistle member defined by an elongate body oriented parallel to the axis of the exit, entrance, and central tube structure to provide audible indication in a range of ten to fifteen knots in advance of stall indication by the electronic stall indicator device.

Abstract: A combination air data probe performs a number of different pressure measurements from a single structure. Measurements of total pressure and total temperature are performed in an improved structural configuration which renders these measurements substantially insensitive to aircraft angle of attack. Static temperature is computed free of recovery factor error because of compensatory effects in the pressure and temperature signals. Another part of the probe provides measurement of static pressure and pressures for determining angle of attack.

Abstract: An indicator meter which may comprise a galvonometer is mounted in a casing having an indexing pointer or "bug" mounted for movement thereon relative to the pointer of an aircraft angle of attack indicator. The settable indexing pointer and the bezel of the casing are integrated with a variable resistor. A reference voltage is fed to the variable resistor such that a voltage is generated which is in accordance with the positioning of the indexing pointer. Thus, a voltage is generated in accordance with the pointer setting which represents the value of a desired angle of attack. The pointer can be set to represent a desired angle of attack with the meter indicating the measured angle of attack. Voltages representing the measured and desired value of angle of attack are compared with a difference or "error" signal is generated.

Abstract: This invention describes an angle of attack sensor for aeronautical use fitted with an electromagnetic device to damp the movement of the rotable part of the sensor and, when required, to position the moving part for test purposes. The damper comprises:a rotor, attached to the moving part and carrying permanent magnets;a stator, attached to the fixed part of the sensor and containing conductors, wrapped into notches, and a ferromagnetic casing placed in front of the notches.The rotor movement is damped by eddy currents generated in the casing when the rotor turns. The rotor is positioned, for test purposes, by the field generated by the stator windings when power is fed to them.

Abstract: Disclosed is a method and probe for measuring the direction and force of gaseous of liquid flows in which two dynamic pressures are measured which are built up in two measuring chambers under the influence of the flow at a certain free-stream angle or a plurality of dynamic pressures are measured which build up in a plurality of measuring chambers under the influence of the flow at a certain free-stream angle, and wherein from the difference or the quotient of measured dynamic pressures or from absolutely or vectorially added measured values, the direction and/or the force of the flow is determined through mathematic processing. The measuring chamber openings are rectangular-shaped or slot-shaped, the center lines of a pair of measuring openings are positioned in a plane, and the arrangement of the measuring chamber openings relative to each other is fixed. The probe can also be used to measure the force of the flow.

Abstract: An air data sensor comprising an elongated probe having a standard, sharped edge, orifice pitot port or opening, and a tapered leading end that is elongated with respect to its lateral dimensions along the longitudinal axis of the probe. The leading end portion blends into the main portion of the probe at a desired relatively short distance downstream from the pitot port. The probe comprises a tube or barrel that can be rectilinear or circular in cross section. Sets of sensing ports are utilizied and at least one pair of ports is oriented on a common axis and facing in opposite directions. Reliable sensing can be obtained when two sets of oppositely facing ports are used with the axis of each set 90.degree. to the axis of the other set. By using the pressure sensed in more than one combination, that is by co-using the pressures, static pressure, impact pressure, angle of attack and angle of sideslip can be derived.

Abstract: In a method of determining the angle of an incident flow at a stationary or moving point of measurement, especially at a point of measurement on a vehicle, the pressure of the incident flow on the surface of a sphere or of a spherical segment is measured. The resulting pressure distribution on the surface is compared with a pressure distribution associated with a defined angle of incident flow and from this the angle of incident flow is calculated, or the angle of displacement of the pressure distribution curve that is found is determined relative to a desired predetermined coordinate system, or relative to a predetermined pressure distribution curve associated with a defined incident flow angle. The determination of the incident flow angle is particularly accurate and can be achieved with minimal measurement complexity in a reliable manner.