Abstract: A system for detecting changes in drilling fluid density downhole during a drilling operation includes a radiation source and detector which are arranged in the outer wall of a drill string sub to measure the density of drilling fluids passing between the source and detector. Radiation counts detected downhole are transmitted to the surface by telemetry methods or recorded downhole, where such counts are analyzed to determine the occurrence of fluid influx into the drilling fluid from earth formations. Changes in the density of the mud downhole may indicate the influx of formation fluids into the borehole. Such changes in influx are determinative of formation parameters including surpressures which may lead to the encountering of gas kicks in the borehole. Gas kicks may potentially result in blowouts, which of course are to be avoided if possible. Hydrocarbon shows may also be indicative of producible formation fluids.

Abstract: For each of two computer systems, logic flowcharts describe background program in which highly detailed memory checksum tests of fixed memory and complementary tests of variable memory are performed, the background program being interrupted for utility programs which are for the most part responsive to transducer or other sensor and discrete inputs to calculate control values for operation of control actuators or other responsive devices. The utility programs include specific self test routines. A direct memory access unit is included in each computer for moving data between inputs of either computer and memories of both, and between the memories of both computers. Periodic testing of fault codes registering the health of each computer is done during utility program routines, any variation from normal causing further health-analysis routines to be performed until dispositive action-causing conditions are determined.

Abstract: A helicopter pitch axis autopilot system, including airspeed hold at cruise speeds and pitch attitude hold below cruise speeds, includes integrated longitudinal acceleration drift corrected by heavily filtered Pitot static airspeed as a filtered airspeed reference, use of a beeper to nudge the airspeed reference above cruise speeds or the pitch attitude reference below cruise speeds, resynchronizing of airspeed reference, pitch attitude reference, pitch autopilot integrator and stick trim position reference, momentarily in response to airspeed transitions between cruise and sub-cruise speeds or in response to initiation of beeping, and continuously during trim release.

Abstract: For each of two computer systems, logic flowcharts describe background program in which highly detailed memory checksum tests of fixed memory and complementary tests of variable memory are performed, the background program being interrupted for utility programs which are for the most part responsive to transducer or other sensor and discrete inputs to calculate control values for operation of control actuators or other responsive devices. The utility programs include specific self test routines. A direct memory access unit is included in each computer for moving data between inputs of either computer and memories of both, and between the memories of both computers. Periodic testing of fault codes registering the health of each computer is done during utility program routines, any variation from normal causing further health-analysis routines to be performed until dispositive action-causing conditions are determined.

Abstract: Faults in a sensor (10) are detected by excess rate fault determination by taking the differentiated (58, 107), rate limited (60, 100, 111) integral (64, 112) from the raw sensor output (72, 113) and indicating a fault (15, 117) in the event that the difference exceeds a predetermined magnitude (76, 114). A null fault (22, 91) is provided in the event that the sensor output does not show a significant change (52, 88) within a given time interval (20, 80) whenever a related sensor (31) indicates (29, 84) that the first sensor (10) should have measurable activity. Both analog (FIG. 1) and digital (FIG. 2, FIG. 3) embodiments are disclosed.

Abstract: A helicopter having an automatic flight control system including an inner, stability loop is rendered less sensitive to short-term, inadvertent pilot inputs by applying a washed-out derivative of a stick position signal to the inner stability loop in a sense to countermand the pilot action. Using a washed-out signal countermands only short-term rapid stick motions, which may be induced by the pilot actively, but inadvertently, or inactively due to coupling between the pilot or the stick and motion of the fuselage, while permitting purposeful, long-term stick positions to have the full, intended effect.

Abstract: For each of two computer systems, logic flowcharts describe background program in which highly detailed memory checksum tests of fixed memory and complementary tests of variable memory are performed, the background program being interrupted for utility programs which are for the most part responsive to transducer or other sensor and discrete inputs to calculate control values for operation of control actuators or other responsive devices. The utility programs include specific self test routines. A direct memory access unit is included in each computer for moving data between inputs of either computer and memories of both, and between the memories of both computers. Periodic testing of fault codes registering the health of each computer is done during utility program routines, any variation from normal causing further health-analysis routines to be performed until dispositive action-causing conditions are determined.

Abstract: An impeller having an axle with radial vanes is mounted within a housing. The housing includes a funnel to direct a large amount of wind into the impeller. Air fins on top of the housing maintain the funnel pointed into the wind. A flap upon the top of the housing will fold downward as the wind increases and this will raise a throttle valve at the throat of the funnel. In addition, the flap will close exhaust openings from the housing, also reducing the wind on the vanes. Two additional flaps act as pressure relief valves in the funnel which open to dump wind at excessive velocity. Furthermore, a leeward flap on the side of the funnel is blown out to an extended position at high winds which causes the housing to rotate upon its circular tracks to bring the funnel opening away from the wind. The air fins on top of the housing are blown down from the vertical position as the wind strikes the housing sideways.The housing is mounted upon a frame which extends horizontally outward from the housing.

Abstract: A pulse circuit periodically produces test pulses of two different amplitudes which are eventually fed in appropriate time intervals to the input of a multi-channel pulse height analyzer to enable continuous monitoring and correction of the offset of the analyzer. Although the amplitudes of both pulses may drift with temperature and time, their amplitude ratio is substantially constant over a broad temperature range. The ratio of numbers, corresponding to the locations of the centroids of the two test pulse peaks in the pulse height analyzer output spectrum, is compared with a reference value of this ratio, and, if the measured ratio deviates excessively from the reference, the offset of the analyzer is adjusted in a direction such that subsequent centroid measurements and ratio comparisons yield tolerably small deviations from the reference ratio.

Abstract: In a helicopter having an automatic pilot system for controlling the main rotor collective pitch, main rotor longitudinal and lateral cyclic pitch, and tail rotor collective pitch, in response to inputs provided from normal sensors, navigational instruments and controls, (which include among others as is known, doppler radar, a pilot panel, an air speed indicator, a radar altimeter, a barometric altimeter and a longitudinal accelerometer), commands to control automatic approach to a desired hover position are provided to the autopilot system in response to signals normally supplied by a TACNAV unit as well as the sensors, navigational units and controls; controls are provided for altitude and rate of descent, so as to terminate in hover at a desired altitude, as well as for turns, courses, and speed so as to approach the desired point of hover upwind and to decelerate in a controlled fashion to hover.