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: An improved aerodynamic vane is used for sensing the angle of attack of an aircraft during yawed flight. Left and right sensors are rotatably mounted to opposite sides of the fuselage of the aircraft and rotate in the air flow to a position indicative of the angle of attack of the aircraft. Each sensor consists of an arm rotatably attached at one end to the aircraft with a vane at the other end of the arm, which vane is canted at an angle with respect to the axis of rotation of the arm. The vanes on the sensors on the opposite sides of the aircraft are both canted down or up as to cause the sensors to take similar angular positions during yawed flight.

Abstract: An improved wind shear warning system for aircraft. A wind shear signal representing wind shear as modified by the downdraft drift angle of the aircraft is used to provide a warning signal when the wind shear signal exceeds (negatively) a variable threshold. The threshold for the warning signal is modified in response to the pilot controlled excess of the airspeed of the aircraft over a reference airspeed during the approach to a landing so as to avoid unnecessary warnings. The threshold is further altered when the wind shear signal during approach indicates the high likelihood of a reversal of wind shear conditions.

Abstract: A keel assembly for a sailboat, the keel assembly having wing-like appendages at the bottom of a fixed keel and having a rotatable flap located at the trailing edge of the fixed keel. The flap includes a cantilevered portion extending below the vertical portion of the keel. In operation, the flap is rotated a few degrees to one side or the other of the center line of the boat so as to create an asymmetrically shaped keel so that the keel and hull exhibit a high lift to drag ratio and efficient sailing performance.

Abstract: A system which provides an increased minimum aircraft pitch attitude during take-off or go-around operations in the event that an unsafe wind shear condition is encountered. A control signal from a wind shear warning system, indicative of a dangerous wind shear condition, is fed to a switching device which controls the velocity command signal to the flight director pitch control. This switching device, in response to the wind shear signal, changes the velocity command to a lower predetermined value, such that the attitude of the aircraft is automatically increased to handle the wind shear encounter.

Abstract: An aircraft speed control system wherein the commanded lift floor (minimum lift) is increased in accordance with an anticipated decrease in headwind between headwind during final landing approach and that anticipated at touchdown. The system includes means for generating a signal which is a function of the difference between the headwind aloft and the headwind anticipated at touchdown. This signal, provided it indicates a decreased headwind at touchdown, is used to modify the programmed lift signal (which is in accordance with the angle of attack of the aircraft) to compensate the decreasing headwind condition, i.e. to increase the commanded lift floor.

Abstract: A digitally coded output is provided from a sensor, such as an aircraft angle of attack sensor. Groups of unused words from the complete unit distance table are omitted between groups of words that are selected to be used in the code, these unused words being "illegal" words indicating an error if they appear in the output of the sensor. The digitally encoded output of the sensor is, in the preferred embodiment, in unit distance code, and is fed to a programmed ROM where it is converted to binary or other convenient code, this binary encoded information representing the sensor output being employed to convey the information provided thereby. The output of the sensor is also fed to a second programmed ROM which has information stored therein indicative of which of the code words are "illegal". Whenever an illegal word is fed to this second programmed ROM, it generates a digital output indicating an error.

Abstract: The output of a transducer providing a signal representing the instantaneous airspeed of an aircraft is differentiated and fed to a summing device. Also fed to the summing device are a signal representing the horizontal acceleration of the aircraft which is subtracted from the instantaneous airspeed signal, and a signal in accordance with the downdraft drift angle of the aircraft which is added to the instantaneous airspeed signal. The output of the summing device represents the magnitude of the wind shear condition (rate of change of wind velocity) as modified by a downdraft drift angle signal. This output signal is fed to appropriate indicator apparatus which may comprise an appropriate display, a peak magnitude storage device, a warning device including a dangerous wind condition and/or a telemetering device providing a reading to a ground station for use in advising other aircraft.

Abstract: A sensing vane is placed near the leading edge of the keel of a sailboat where the water flow splits. The vane is deflected away from a "center" position (i.e., a position aligned with the keel) by the water stream as a function of the water flow angle (the angle between the heading of the boat and its path through the water). The rotational movement of the vane is sensed by a synchro transmitter which drives a synchro follower positioned at a location near the helm of the boat where it drives an indicator dial. The indicator dial is appropriately calibrated for each boat to provide a direct reading of flow angle, the ratio between the side force of the water on the keel (S.sub.k) and the water drag force (D.sub.k) being a function of this angle. The dial is marked to provide an indication when optimum flow angle (i.e., that for maximum S.sub.k /D.sub.k) is being achieved. In addition, an alerting signal may be provided when such optimum condition exists.

Abstract: A light weight, low power radar principally adapted for use on small vehicles such as sailboats, which has a fixed antenna providing a continuous forward looking beam which provides range information and limited azimuth information in manual and automatic range scanning modes of operation, and which is capable of automatically tracking targets in range. In the manual mode of operation, a voltage representing a manually selected range is compared with a sweep voltage synchronized with the radar transmitter pulse to generate a pulse having a time relationship to the transmitter pulse corresponding to the selected range. This pulse is utilized to gate a video echo from the radar receiver to logical control circuit which operates in conjunction with the antenna lobing control to actuate a display indicating whether the target is to port or starboard of the vehicle heading. The range voltage is also converted to digital form for display on a digital display device.

Abstract: An automatic pilot for a sailboat includes a mode switching arrangement which permits a person to operate the sailboat in any one of several modes. One is the STEER mode, a second is the OFF mode, a third is the STANDBY mode, a fourth is the WIND mode and a fifth is the COMPASS mode. Another switching arrangement enables either the WIND mode or COMPASS mode to be operated in COURSE CHANGE sub-mode manners. Various mechanisms and circuitry further are included to enable the sailboat to be manually steered, to stabilize the rate of change of rudder position, to null a control that is a function of the change in heading error, to wash out certain signals under certain conditions, to inhibit certain signals under certain conditions, and to provide a steering command that furnishes a visual direction to the steersman when the automatic pilot is in a COURSE CHANGE sub-mode.

Abstract: An electrical signal in accordance with the direction of the wind relative to the heading of a sailboat is generated by means of a wind direction sensor and a transducer. This signal is fed to a summing device where it is summed in opposite polarity relationship with a signal in accordance with changes in rudder position from its neutral position, signals representing a steady state condition of the rudder being "washed out". The output of the summing device which represents the apparent wind direction (relative to boat heading) as modified by a change of rudder signal provides an "apparent wind track" error signal which is used to drive a servo motor. The output of the motor is coupled to a gear, this gear driving an indicator which provides a reading which can be used by the helmsman in reaching a desired wind track. The output of the gear is also used to drive the transducer means so as to zero its output to complete the servo loop formed.

Abstract: The output of a transducer providing a signal in accordance with the instantaneous air speed of an aircraft is differentiated and fed to a summing device which subtracts therefrom a signal in accordance with the horizontal acceleration of the aircraft, this signal being derived from the output of an inertial instrument such as an accelerometer. The output of the summing device represents the magnitude of the wind shear condition (rate of change of wind velocity with changes in altitude). This signal is fed to appropriate indicator means which may comprise an appropriate display, a peak magnitude storage device, a warning device indicating a dangerous wind shear condition, or a telemetering device providing a wind shear reading to a ground station for use in advising other aircraft.

Abstract: The drive for the indicator mechanism of an altimeter is connected so as to drive altitude marker means, the relative position of such marker means being indicative of altitude. The marker means has a marker which may be implemented by a slot formed therein to reference this position. Sensor means is mounted in proximity to and for movement relative to the marker means. The sensor means is manually set to a position relative to the marker means by means of an altitude alert setting device, the set position representing an altitude at which an alerting signal is desired. When the marker means is driven by the altimeter mechanism so that the marker arrives opposite the sensor means, thus indicating that the marker means and the sensor means are both at positions representing the same altitude, a signal is generated by the sensor means which is used to appropriately actuate a signal device indicating that the alerting altitude has been reached.

Abstract: A radar principally for use on small vehicles such as sailboats, utilizing a fixed antenna which provides a continuous forward looking beam and has a dual range display providing range and limited azimuth information. Separate antenna elements are utilized to receive echoes in the paths of left and right radar beams respectively, these left and right beams being slightly to the left and right of the boresight of the radar antenna. Utilizing digital techniques, the video representing radar echoes received in the left and right beams is gated in proper time sequence corresponding to target range, to a series of indicator lights for left and right range display respectively. These indicator lights each represent a different target range and are excited in accordance with video signals received in the left and right beams respectively.

Abstract: A system for detecting the presence of water in an aircraft fuel sump with the aid of a pair of electrodes to which a detector circuit is connected. When both electrodes touch water in the sump below the fuel the detector circuit energizes a warning signal. The electrodes are connected to the opposite ends of a winding of a transformer having another winding which forms a leg of a voltage divider. The other leg of the voltage divider constitutes a resistor. The voltage divider is energized by an AC source of electrical energy whereby AC energy is applied to the electrodes. A signal taken from across the resistor is applied to an operational amplifier the output of which is adapted to trigger a solid state switch having an output connected to an electrically activatable warning device.

Abstract: A radar principally for use on small vehicles such as sail boats, utilizing a fixed antenna which provides a continuously forward looking beam and which provides a range display only. Utilizing digital techniques, the video representing radar echoes is gated in proper time sequence corresponding to target range to a series of indicator lights. These indicator lights each represent a different target range, and thus provide a display indicating the range at which various targets forward of the vehicle are located.

Abstract: An electrical signal in accordance with the direction of the wind relative to the heading of a sailboat is generated by means of a wind direction sensor and a transducer. This signal is fed to a summing device where it is summed in opposite polarity relationship with a signal in accordance with changes in rudder position from its neutral position, signals representing a steady state condition of the rudder being "washed out." The output of the summing device which represents the apparent wind direction (relative to boat heading) as modified by a change of rudder signal provides an "apparent wind track" error signal which is used to drive a servo motor. The output of the motor is coupled to a gear, this gear driving an indicator which provides a reading which can be used by the helmsman in reaching a desired wind track. The output of the gear is also used to drive the transducer means so as to zero its output to complete the servo loop formed.

Abstract: An improved wind shear warning system for aircraft. A wind shear signal representing wind shear as modified by the downdraft drift angle of the aircraft is used to provide a warning signal when the wind shear signal exceeds (negatively) a variable threshold. The threshold for the warning signal is modified in response to the pilot controlled excess of the airspeed of the aircraft over a reference airspeed during the approach to a landing so as to avoid unnecessary warnings. The threshold is further altered when the wind shear signal during approach indicates the high likelihood of a reversal of wind shear conditions.