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Blade pitch

About: Blade pitch is a research topic. Over the lifetime, 5321 publications have been published within this topic receiving 63134 citations.


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Patent
19 Mar 1971
TL;DR: A support, actuation and balancing structure for rotor blades in a variable blade angle axial flow fan, compressor or turbine as may be used in a turbojet or turbofan engine is described in this paper.
Abstract: A support, actuation, and balancing structure for rotor blades in a variable blade angle axial flow fan, compressor or turbine as may be used in a turbojet or turbofan engine. The supporting structure may include a shaft attached to each rotor blade and restrained from outward radial travel, under high centrifugal loading, by the inwardly facing surfaces of two spaced apart discs. Actuation may be provided by at least one fluid powered piston which controls blade angulation through rotation of one disc member relative to the other. Centrifugally controlled balancing means may also be provided to insure a uniform flow condition through the blades by maintaining the blades in a stable position of angulation upon disengagement of the actuator. Each rotor blade preferably includes a central axis about which the blade angle is varied, and which is in close proximity to the intersection of the leading edge of the blade with the blade tip.

31 citations

Patent
08 Mar 2006
TL;DR: In this paper, a wind power generation system consisting of a wind turbine rotor 2 having a blade having variable pitch angle, a pitch control mechanism 22 controlling the pitch angle by driving the blade 5, and an emergency power supply mechanism 29 for supplying a power generated by the rotation of the wind turbines rotor 2 to the pitch controller mechanism 22 in response to the occurrence of an abnormality that the system voltage of a power system 13 lowers.
Abstract: PROBLEM TO BE SOLVED: To provide an LVRT (low voltage ride through) ability to a wind power generation system by a mechanism not requiring much maintenance. SOLUTION: This wind power generation system comprises a wind turbine rotor 2 having a blade 5 the pitch angle of which is variable, a pitch control mechanism 22 controlling the pitch angle by driving the blade 5, and an emergency power supply mechanism 29 for supplying a power generated by the rotation of the wind turbine rotor 2 to the pitch control mechanism 22 in response to the occurrence of an abnormality that the system voltage of a power system 13 lowers. COPYRIGHT: (C)2007,JPO&INPIT

31 citations

Patent
01 Feb 1983
TL;DR: The horizontal axis wind tubrine converts wind into electrical energy and includes a pitch control vane with a flyweight mechanism on each rotor blade to provide aerodynamic efficiency at operating wind velocities, near constant speed and zero lift pitch of the rotor blades when speeds exceed the design speed of the system as discussed by the authors.
Abstract: The horizontal axis wind tubrine converts wind into electrical energy and includes a pitch control vane with a flyweight mechanism on each rotor blade to provide aerodynamic efficiency at operating wind velocities, near constant speed and zero lift pitch of the rotor blades when speeds exceed the design speed of the system. A gravity neutralization means composed of a bevel gear and pinions couples the blades together while a flyweight arrangement connected to the bevel gear acts to neutralize centrifugal torque on the blades.

31 citations

Patent
06 Aug 1993
TL;DR: In this paper, an active stabilization system is associated with each rotor blade to overcome the instability previously associated with leading edge servo flaps and to reduce the complexity of the control signals needed to be produced by the control signal generating means.
Abstract: In a helicopter having a main rotor with blades controlled in pitch by servo flaps the servo flaps are arranged in advance of the leading edges of the blade to provide increased lift efficiency of the rotor system. The signals for controlling the pitches of the blade are generated by a computer implemented means responsive to pilot command signals and flight parameter signals and are transmitted from the stationary structure of the helicopter to the rotating structure through a non-mechanical stationary-to-rotary interface. An active stabilization system is associated with each rotor blade to overcome the instability previously associated with leading edge servo flaps and to reduce the complexity of the control signals needed to be produced by the control signal generating means.

31 citations

Patent
15 Jan 1997
TL;DR: In this paper, a high performance, multiple rotor riding trowel for finishing concrete and hydraulic controls therefor, enabling complete hand control to the operator of steering, propulsion, and blade pitch.
Abstract: A high performance, multiple rotor riding trowel for finishing concrete and hydraulic controls therefor, enabling complete hand control to the operator of steering, propulsion, and blade pitch. A rigid trowel frame mounts two or more downwardly-projecting, bladed rotor assemblies that frictionally engage the concrete surface. The rotor assemblies are tilted with double acting hydraulic cylinders to effectuate steering and control. Double acting hydraulic cylinders also control blade pitch. A joystick system enables the operator to hand control the trowel with minimal physical exertion. The joystick system activates solenoid control valves that in turn energize the various hydraulic cylinders that tilt the rotors and alter blade pitch. The rotor gearboxes are mounted to tiltable, pivot steering boxes secured to the frame within suitable mounting regions bounded by rigid frame elements. The rotor assembly blades contact plastic concrete to finish the surface while supporting the trowel.

31 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202377
2022163
202184
2020110
2019105
2018109