Abstract: A method for doing an optimization of the performance envelope initially authorized for an existing rotorcraft engine (M) to enable the engine (M), to be used in an optimized performance envelope that is different from the performance envelope initially authorized for the engine, is remarquable in that this optimization is compensated by modifying the total service life of the engine (M).

Abstract: For constant-speed synchrophasing of the propellers (14) of the propulsion units (10) of an aircraft each equipped with an electronic control circuit (20) connected to a communications network (32) of the aircraft, each control circuit of a propulsion unit includes a clock delivering a clock signal at a frequency representing a rotational speed of the propulsion unit propeller corresponding to said constant speed, the control circuit clocks are kept substantially synchronous by communication via the communications network of the aircraft, and in each propulsion unit, the offset between the clock signal and a signal produced from a propeller rotational speed sensor is measured and compared to a determined propeller phase value assigned to the propulsion unit and, depending on the result of the comparison, an instantaneous variation of the propeller rotational speed is applied as necessary so as to bring the measured offset to the determined value.

Abstract: A fan system includes a fan and a fan rotation speed control. The speed control is operable to command the fan to rotate at a speed selected from a certain range of rotation speeds. A fan oscillation detector may be coupled with the fan to detect oscillation of the fan as the speed control is operated to rotate the fan at various speeds among the range of fan rotation speeds. The fan oscillation detector may comprise an accelerometer or other device. Oscillation amounts detected by the oscillation detector are compared against each other or against an oscillation threshold value. A programmer device identifies fan rotation speeds at which the oscillation amount exceeds the threshold or is otherwise unacceptable, and programs the fan rotation speed control to prevent an operator from being able to select those speeds at which the oscillation amount exceeds the threshold or is otherwise unacceptable.

Abstract: A blade-pitch-angle control device includes a memory unit in which predetermined parameters that affect the load fluctuation of blades, azimuth angles, and pitch-angle command values are stored in association with each other; an azimuth-angle detecting unit that detects the azimuth angle of each of the blades; a parameter-detecting unit that detects the predetermined parameters; a command-value receiving unit that receives pitch-angle command values for each of the blades from the memory unit, the pitch-angle command values being selected on the basis of the azimuth angle of each blade detected by the azimuth-angle detecting unit and the predetermined parameters detected by the parameter-detecting unit; and a pitch-angle-control command-value generating unit that generates pitch-angle-control command values for individually controlling the pitch-angle of each blade on the basis of the pitch-angle command values and a common-pitch-angle command value.

Abstract: The present invention relates to a method of controlling the aerodynamic load of a wind turbine's blades individually in such a way that the dynamic aerodynamic loads on the turbine are reduced and power production is optimised. In general the present invention will improve the overall stability of the turbine leading to reduce fatigue loads, reduced extreme loads during operation and reduced risk of blade-tower interaction. In particular preferred embodiment of the invention, flow properties are measured locally on the different blades or in front of the blades and from these measurements the pitch angle settings are changed, in other ways changing the aerodynamic properties, for the blades through a control unit.

Abstract: A method for limiting loads in a wind turbine by using measured loads or wind speed to increase the minimum pitch angle for extended periods. The minimum pitch angle will be allowed to relax down to the default when load excursions diminish. The method will allow turbines to capture more energy by operating in higher wind speeds and/or utilizing larger rotors without additional loss of fatigue life.

Abstract: Four actuators are instructed to move to a condition indicated by a demand line 81. Their actual conditions are indicated by four arrows. The method determines if the range 84 of actual conditions exceeds a threshold value, representing an unacceptable mismatch of actuator positions. This comparison is used to establish further demand instructions. For example, if the range is too great, and the average 82 is below the demand line 81, the devices are instructed to move to the upper extreme position at 88. If the average position 82 is above the demand line 81, the devices are instructed to move to the lower end of the range, at 90. This results in the actuator positions moving together, as they also move toward the demand line 81, reducing risks associated with actuator mismatches.

Abstract: A method for reducing peak loads of wind turbines in a changing wind environment includes measuring or estimating an instantaneous wind speed and direction at the wind turbine and determining a yaw error of the wind turbine relative to the measured instantaneous wind direction. The method further includes comparing the yaw error to a yaw error trigger that has different values at different wind speeds and shutting down the wind turbine when the yaw error exceeds the yaw error trigger corresponding to the measured or estimated instantaneous wind speed.

Abstract: An electric turbine includes a fan with a plurality of blades each with a tip having a permanent magnet positioned in the tip. The fan is mounted for rotation about an axis with the blades extending radially outwardly from the axis of rotation and with the tips adjacent an outer extremity. An electromagnet and a magnetic sensor are each positioned to be magnetically aligned with the permanent magnet in the tip of each blade during one complete rotation of the fan. A controller supplies a pulse of current, in response to reception of a sensor signal from the magnetic sensor, to the electromagnet at a time when the electromagnet is magnetically aligned with the permanent magnet in one blade of the fan. A solar panel supplies power to the controller.

Abstract: A method for detecting ice on a wind turbine having a rotor and one or more rotor blades each having blade roots includes monitoring meteorological conditions relating to icing conditions and monitoring one or more physical characteristics of the wind turbine in operation that vary in accordance with at least one of the mass of the one or more rotor blades or a mass imbalance between the rotor blades. The method also includes using the one or more monitored physical characteristics to determine whether a blade mass anomaly exists, determining whether the monitored meteorological conditions are consistent with blade icing; and signaling an icing-related blade mass anomaly when a blade mass anomaly is determined to exist and the monitored meteorological conditions are determined to be consistent with icing.

Abstract: System for controlling the torsional stability of the drivetrain of a machine, in particular of a helicopter. The system (1) comprises a means (7) for acting on the speed of an engine (5) of the power train of the machine, a means (8) for measuring a speed NTL of rotation of the free turbine of the engine (5), a correction device (9) for correcting the measured speed NTL into a corrected value NTLcorr, a means (11) for determining a preset value NTLpres of the speed of rotation of the free turbine of the engine (5), and a a computation unit (12) for automatically computing, on the basis of the preset value NTLpres and of the corrected value NTLcorr, operating commands which are applied automatically to the first means (7). The correction device (9) corrects the measured speed NTL so as to obtain a corrected value NTLcorr exhibiting, at least around the first torsional mode of the drivetrain, the same modulus and an opposite phase with respect to the preset value NTLpres.

Abstract: In the control system for a turbo-charged diesel aircraft engine, the engine speed and the fuel injection amount are controlled by a single control lever. However, when the control lever is operated to accelerate the engine, the fuel injection amount immediately increases to the value set by the control lever while the actual speed of the engine requires a relatively long time to reach the set speed. This may cause the actual fuel injection amount to become excessively larger than a value matching the engine speed and to produce exhaust smoke. In order to prevent this problem, the control system includes a delay control device which restricts the rate of increase in the fuel injection amount to a value less than a predetermined maximum value. By restricting the rate of increase in the fuel injection amount, the actual fuel injection amount is maintained at a value matching the actual engine speed during acceleration, and the generation of the exhaust smoke does not occur.

Abstract: An engine synchronization system for a pair of turbo jet engines in a twin jet aircraft includes a subsystem for selecting a power output, a signal generator for producing a first output signal in response to the speed of a first engine and a signal generator for producing a second output signal in response to the speed of a second engine. The system also includes a selector for selecting the fan speed or compressor speed of the engines as a control. The system incorporating an averaging device for calculating the average of the engine speeds and causing the servo driven throttle controller to retard the faster and advance the slower throttles toward the average. The engine synchronization system also includes a split shaft assembly including first and second output shafts which are disposed on a common axis. Each of the output shafts is locked to a servo motor and are free to rotate with respect to one another.

Abstract: A method for measuring and controlling oscillations in a wind turbine with the wind turbine control system using spectrum analysis, to determine the existence and amplitude of vibrations on the basis of existing sensor/transducer signals relating to the characteristics of the electrical power output. The control system of the wind turbine is adapted to attenuate the oscillations before they reach an unacceptable level, and thereafter to cause the wind turbine to resume normal operation.

Abstract: An apparatus for monitoring the health of a compressor including at least one sensor operatively coupled to measure the dynamic pressure of gases flowing through the compressor, a processing system coupled to at least one sensor, the processor system recording and processing the measurements made by at least one sensor. The apparatus further includes a comparator that compares the sensor measurements with predetermined baseline values, and a real-time controller coupled to the comparator, the controller initiating corrective actions to prevent a compressor surge if the sensor measurements deviate from the predetermined baseline values.

Abstract: Maintenance requirements on a variable pitch propeller control system are minimized by eliminating the need for mechanical elements, such as a flyweight, mechanism in a secondary control for the variable pitch propeller. The system includes a secondary control (40) operating a pitch change mechanism (24) in response to the existence of at least one undesirable propeller condition and includes a target (34), (38) along with a target pickup (32), (36) for sensing the target (34), (38) and providing information to a function generator (76) which in turn provides information to a logic device (78), (80), (82), (84), (86), (88), (94) which in turn is connected to the pitch change mechanism (24) for operating the same.

Abstract: A control algorithm provides a method for selecting a pitch magnitude for a controllable pitch propeller. The pitch magnitude is selected as a function of the difference between a desired engine speed and an actual engine speed in addition to the actual pitch position of the controllable pitch propeller. The desired engine speed is selected as a function of the position of either a throttle control lever or the throttle plate of an internal combustion engine.

Abstract: An electronic self-powered propeller governor driven off the aircraft engine includes a drive shaft which drives a hydraulic pump to produce pressurized oil to move a hydraulically controlled piston connected to the propeller blade for changing the blade pitch. A hydraulic control valve which controls the position of the piston includes a spool which is positioned within the drive shaft and supplies pressure to the piston for changing the pitch of the propeller blade. The drive shaft also drives an AC generator producing an electrical RPM signal which is supplied to a linear control circuit. A manually operated RPM control produces an electrical signal supplied to said linear control circuit which is compared with the RPM signal produced by the generator and in turn the linear control circuit signals an actuator.

Abstract: A propeller pitch control apparatus for an aircraft in which the vector sum of the aircraft forward speed and the propeller rotational tip speed is a selected fraction of the speed of sound, the fraction based on percent power and altitude, to maximize efficiency and minimize noise.

Abstract: A propeller is controlled to change pitch at at least two different rates. In one embodiment, an electric motor is provided with a high or low voltage for driving a pitch change mechanism at a high or low change rate. Preferably the rate is selected automatically. Preferably, the high rate is not used unless the current pitch is below a threshold.

Abstract: An improved saddle stitching apparatus has dual scoring disks which cooperate with a scoring drum to create a flat spine on a cover. In one embodiment, a split ring is provided with two clamp arms, so that the ring can be releasably secured to the scoring drum. The ring includes a pair of annular grooves, with the distance between the grooves being of the desired spine width. The scoring disks are positioned adjacent the grooves so as to form the scoring lines. A folding assembly is also disclosed, which utilizes a flat carrying belt and a V-belt for purposes of folding the cover and moving the cover toward a stitching station. A gathering chain is also utilized to deliver the cover and signatures to the stitching station. The station includes a guide to assist in directing the preassembled covers and signatures toward a stitching head. Also provided is a block guide and an anvil for assistance in centering the spine beneath the stitching head.

Abstract: An air driven turbine having variable pitched blades is provided that includes a pitch change mechanism and associated control circuits for automatically adjusting the pitch of the blades during either rotating or non-rotating operational modes of the air driven turbine. The pitch control mechanism includes a resettable overspeed protection device which is directly actuated by an overspeed condition of the turbine and operates independently from the pitch change mechanism to move the blades to a failsafe, feathered, or coarse pitch, low speed position. The pitch control mechanism utilizes a linear actuator in the form of an acme screw drive. The air driven turbine includes a ball ramp thrust bearing for attaching the blades to a hub of the turbine in such a manner that during rotation of the turbine actuation loads on the pitch change mechanism are reduced.

Abstract: A synchrophaser for a multi-engine, propeller-driven aircraft including a filter that automatically compensates for misalignment of blade position sensor tabs through derivation and application of a correlation coefficient. The correlation coefficient is calculated in a self-adjustment derivation, utilizing a dynamic tolerance band, providing increased accuracy in propeller speed determination. The correlation coefficient brings about an apparent uniform distribution of blade position sensors, as seen by the synchrophaser, thus eliminating a primary source of cyclic propeller speed disturbances. The correlative filer accomplishes its task without the phase shifting normally encountered in other digital filtering technique.

Abstract: A marine drive has a propeller rotatable about a drive axis and having a plurality of blades themselves pivotable about respective blade axes projecting generally radially from the drive axis and each movable between a low-pitch end position extending generally parallel to a plane perpendicular to the drive axis and a high-pitch end position extending at a large acute angle to the plane. An engine rotates the propeller about the drive axis at a variable drive speed in a forward rotation direction. The blade axes are so positioned relative to the respective blades that on forward rotation of the propeller the blades are urged into one of their end positions. A single-acting hydraulic actuator connected to the blades has a compartment pressurizable to displace the blades into the other of the end positions.

Abstract: A method and apparatus for controlling a propulsion engine output in a vessel, based on the net axial force on a propeller shaft in the vessel. The apparatus includes a regulating loop with a computer which continuously controls the delivery of fuel to the vessel's engine, and optionally controls the attack angle of the vessel's propeller blades. Control of the fuel delivery is performed in accordance with predetermined control algorithms, and optionally, by operator-set parameter values and maneuvering operations. The apparatus further includes at least one force sensor mounted to a bearing which supports the vessel's propeller shaft. The force sensor, which is preferably mounted to a thrust bearing, detects a net axial force on the propeller shaft. The net axial force detected is then used as a parameter in the control algorithms and therefore as a factor in controlling the delivery of fuel.

Abstract: An electric pitch control apparatus for a variable-pitch propeller equipped with a pitch control mechanism having an electrically controlled actuator for controlling a pitch angle of the propeller blade in accordance with a control current applied thereto. The electric pitch control apparatus is designed to compensate a difference between target and actual pitch control amounts caused by a secular change of the pitch control mechanism thereby to effect an accurate control of the propeller pitch.

Abstract: An electric pitch control apparatus for a variable-pitch propeller capable of properly controlling the pitch angle of the propeller blade in accordance with instantaneous operational conditions of the propeller and of effecting adjustment of the pitch angle of the propeller blade without any delay of a time in response to operation of the engine output lever for promptly coinciding an actual rotational number of the prime engine with a target rotational number.

Abstract: A control system, having an input command signal and driving a prime mover, is provided with variable magnitude and/or rate input signal limiting that is adjusted by maps 68,70,72,74 which set the limits for a variable magnitude limiter 14 and a variable rate limiter 22 as a function of the prime mover rate. The limiting is adjusted dynamically as the prime mover rate changes. When the prime mover enters an undesirable operating condition, the maps only limit the command signal in the direction of such condition. The adjustable limiting is enabled or disabled based on the position, rate, and/or acceleration of the prime mover.

Abstract: A pitch control apparatus for a variable pitch propeller for drive connection to an aircraft engine, wherein an optimum rotation number of the engine is calculated in relation to a flight speed of the aircraft, an opening degree of the engine throttle and the density of atmospheric air in flight of the aircraft to maximize a thurst force acting on the aircraft, and wherein a pitch angle of the propeller blade is controlled in such a manner that the rotation number of the engine becomes substantially equal to the optimum rotation number.

Abstract: A speed and phase sensor counterrotates aircraft propellers. A toothed wheel is attached to each propeller, and the teeth trigger a sensor as they pass, producing a sequence of signals. From the sequence of signals, rotational speed of each propeller is computer based on time intervals between successive signals. The speed can be computed several times during one revolution, thus giving speed information which is highly up-to-date. Given that spacing between teeth may not be uniform, the signals produced may be nonuniform in time. Error coefficients are derived to correct for nonuniformities in the resulting signals, thus allowing accurate speed to be computed despite the spacing nonuniformities. Phase can be viewed as the relative rotational position of one propeller with respect to the other, but measured at a fixed time. Phase is computed from the signals.

Abstract: An aircraft engine propeller synchrophasing system (4) has a gain stage (8) which varies the gain of the system (4) according to the magnitude of the difference between the preferred propeller relative phase and the measured propeller relative phase.

Abstract: An apparatus for controlling the phase of a slave propeller relative to that of a master propeller is shown and described. A logic means having a trajectory function, F(.phi..sub.E), which defines the region for phase holding, i.e. where the error correction signal, .phi..sub.EC, equals phase error .phi..sub.E. In the region of phase holding, normal control is achieved and there is no slipping of control from a first propeller blade to a second propeller blade.

Abstract: A ground mode pitch position logic and control is shown and described in this invention. A method for scheduling and limiting the pitch actuator reference signal in accordance with the actuator commanded schedule, propeller overspeed and propeller underspeed.

Abstract: A method and apparatus for providing improved phase error measurement as shown and described. The measured phase error (.phi..sub.E) is used as an input to a SYNCHROPHASER.RTM. control which provides for phase control of a slave propeller with respect to a master. The phase error (.phi..sub.E) is the sum of the sensed phase error and 360.degree. divided by N.sub.p times .phi..sub.count minus .phi..sub.ref. .phi..sub.count is a counted number of phase discontinuities which occur in .phi..sub.S, the sensed phase. The values of .phi..sub.count and .phi..sub.E, measured phase output, may be limited in number and magnitude.

Abstract: An aircraft engine propeller autofeather system (4) has a feather solenoid (8) which is actuated by either a signal provided by an engine power loss detector (10) or a signal provided by an engine overspeed detector (12). The overspeed detector (12) detects excessive propeller speed by comparing the speed to a first predetermined value (21) or by comparing the speed rate of change to a second predetermined value (23) combined with comparing the speed to a third predetermined value (25).

Abstract: A propeller speed governor having a derivative feedback of propeller speed and having a means such as a switch to open the derivative feed back loop when airspeed exceeds a predetermined amount is shown and described. This derivative inhibit is used to provide improved dynamic compensation at high and low speeds.

Abstract: A propeller overspeed governor logic and control is described in this invention. A method is shown for providing a variable propeller pitch rate from a discrete pitch command to improve governing dynamic characteristics.

Abstract: Propeller phase control apparatus for use on multi-engine aircraft having, for each engine, an electronic engine control (EEC) for providing an EEC command speed and phase (S/P) signal to control propeller phase and shaft speed, and a speed and phase control (SPC) for regulating the propeller's blade pitch angle to adjust the shaft speed thereof in dependence on the EEC command S/P signal value, includes: a SYNCHROPHASER Reference Unit (SRU) having a signal processor with signal memory, the memory including stored signals definitive of a speed and phase algorithm, the signal processor calculating a common SRU command S/P signal value for all SPCs in accordance with the algorithm and in dependence on the sensed values of selected flight data indicative of engine performance, and further includes an electronic switch for each SPC, for selecting either the SRU command S/P signal of the engine's EEC command S/P signal for presentation to the SPC.

Abstract: In the invention, the speeds of both propellers in a counterrotating aircraft propeller pair are measured. Each speed is compared, using a feedback loop, with a demanded speed and, if actual speed does not equal demanded speed for either propeller, pitch of the proper propeller is changed in order to attain the demanded speed. A proportional/integral controller is used in the feedback loop. Further, phase of the propellers is measured and, if the phase does not equal a demanded phase, the speed of one propeller is changed, by changing pitch, until the proper phase is attained.

Abstract: Control system for synchrophasing the propellers of an aircraft, each propeller provided with a blade pitch controller for controlling the blade angle of the propeller, the systen containing for each propeller a control loop, comprising: a revolution rate controller, means for determining the blade passing frequency, an adjustable propeller revolution rate reference source supplying a revolution rate setpoint control signal, comparator means for comparing the blade passing frequency with said setpoint to generate an error signal for the revolution rate controller.

Abstract: An improved slave propeller SYNCHROPHASER.RTM. device and mode logic for a multi-propeller aircraft is disclosed. A designated master propeller has at least one associated slave propeller which has its speed and phase controlled with respect to the master by initially controlling the speed of the slave propeller to within a selected constant number of RPM of the master so that the master and slave propellers are periodically in phase and then switching to phase control for controlling the speed of the slave propeller in the presence of a phase difference signal having an absolute magnitude less than a selected absolute magnitude. A selected phase difference relationship between the master and the slave may thus be effected with minimum transient effect on the speed of the slave propeller.

Abstract: An improved slave propeller synchrophaser (10) includes a first control (14) responsive to a phase difference signal (28) and a phase difference reference signal (26) for providing a phase error signal (112) and for providing a propeller speed reference bias signal (40) for a speed governor (46), and also includes, according to the present invention, a second control (12) responsive to the phase error signal (112) for providing an engine power reference bias signal (80) for an engine power control for providing a very limited amount of propeller fine speed control within the dead band of the propeller speed governor while at the same time substantially maintaining engine power at the commanded power level.

Abstract: Damping of the primary bending mode of a tower (12) mounting a wind turbine having a control (36) for providing a pitch blade angle reference signal (40) to modulate the pitch of the turbine blades (1) through a pitch change mechanism (38) for constant power is provided by generating the pitch blade angle reference signal as the integral (104) of the summation (266) of a torque/power controlling blade pitch angle reference rate signal (98) with an estimated acceleration signal (255) generated by filtering (250, 252, 254) the blade pitch angle reference signal (40) with the following transfer function ##EQU1##

Abstract: An accelerometer (1) disposed on the support tower (12) of a wind turbine electric generating system in the vicinity of the rotor (10, 16) thereof provides a signal (1) indicative of acceleration of the tower in the direction of the rotor rotational axis. The signal (2) is passed through a band-pass filter (4) for summation (9) with a torque/power controlled (100) blade pitch angle reference rate signal (98), the integral (104) of which provides a blade pitch angle reference signal (40) to control the pitch angle of the rotor blades (10) through a pitch change mechanism (38), thereby to provide additional, positive aerodynamic damping to the tower while modulating blade angle for constant torque/power in response to wind turbulence.

Abstract: A vertical axis windmill having a rotating structure is provided with a series of articulated vertical blades whose positions are controlled to maintain a constant RPM for the rotating structure, when wind speed is sufficient. A microprocessor controller is used to process information on wind speed, wind direction and RPM of the rotating structure to develop an electrical signal for establishing blade position. The preferred embodiment of the invention, when connected to a utility grid, is designed to generate 40 kilowatts of power when exposed to a 20 mile per hour wind. The control system for the windmill includes electrical blade actuators that modulate the blades of the rotating structure. Blade modulation controls the blade angle of attack, which in turn controls the RPM of the rotor. In the preferred embodiment, the microprocessor controller provides the operation logic and control functions.