Methods, apparatus, systems, and articles of manufacture are disclosed to adjust a pitch axis of a blade of an engine. An example blade apparatus includes: a hub to facilitate movement of blades in an engine, the engine having a radial center line; and a trunnion connected to the hub. The example trunnion includes a slot to accommodate a first blade, and at least one of the trunnion or the first blade is positioned with at least one of a tilt or a lean with respect to the radial center line to form a pitch axis offset from the radial center line such that the pitch axis is not parallel to or co-linear with the radial center line. The example hub is to rotate the first blade about the pitch axis.

A vertical wind turbine includes a shroud for directing vehicle-created wind towards the turbine blades, which are oriented in response to wind direction.

Methods, systems, and devices for dynamic wind turbine rotational speed control are described. The method may include attaching a vane shaft to a support arm of the wind turbine, the vane shaft partially inserted into a cylindrical aperture of an airfoil of the wind turbine, rotating an airfoil around a vertical axis of the wind turbine, and controlling, via a torsion spring of the wind turbine, when a rear stop of the speed control assembly exerts a force on the airfoil to reduce the rotational speed of the wind turbine, where the torsion spring is configured to facilitate the rear stop to exert the force on the airfoil when a rotational speed of the wind turbine around the vertical axis exceeds a set rotational speed, where a portion of the vane shaft is inserted into a helical portion of the torsion spring.

Methods, apparatus, systems, and articles of manufacture are disclosed for a slot to accommodate a blade of an engine. An example apparatus includes: a socket to receive an end of a blade; and a retaining device to interact with the socket and the blade for retention of the end of the blade in the socket. The example retaining device includes: a spacer to be positioned in the socket with the end of the blade; a wedge positioned inside the spacer; and a spring to tighten to pull the wedge to expand the spacer.

The twist morphing blade for wind turbine is a blade adapted for attachment to the hub of a wind turbine. The blade has a central shaft extending between the root and tip ends of the blade. A guide track is defined in the central shaft. A sliding mass is slidably disposed in the guide track and bears against a bias spring. A driven shaft is coaxially disposed around the sliding mass and bias spring and rotatably coupled to the sliding mass. Connecting rods extend between the driven shaft and root end of the blade and through active and passive ribs alternately spaced between the driven shaft and the root end of the blade. When incident wind rotates the rotor, centrifugal force linearly slides the mass, which rotates the driven shaft and the connecting rods to deflect the ribs, twist morphing the medial sections of the blade.

Methods, apparatus, systems, and articles of manufacture are disclosed for a slot to accommodate a blade of an engine. An example blade apparatus includes: a collet including a slot to receive an end of a blade; and a plurality of retainers including a first retainer positioned on a first end of the collet and a second retainer positioned on a second end of the collet to provide axial retention for the blade in the slot.

Methods, apparatus, systems, and articles of manufacture are disclosed for a slot to accommodate a blade of an engine. An example blade apparatus includes: a collet including a slot to receive an end of a blade; and a plurality of retainers including a first retainer positioned on a first end of the collet and a second retainer positioned on a second end of the collet to provide axial retention for the blade in the slot.

Methods, apparatus, systems, and articles of manufacture are disclosed for a slot to accommodate a blade of an engine. An example apparatus includes: a socket to receive an end of a blade; and a retaining device to interact with the socket and the blade for retention of the end of the blade in the socket. The example retaining device includes: a spacer to be positioned in the socket with the end of the blade; a wedge positioned inside the spacer; and a spring to tighten to pull the wedge to expand the spacer.

Methods, apparatus, systems, and articles of manufacture are disclosed to adjust a pitch axis of a blade of an engine. An example blade apparatus includes: a hub to facilitate movement of blades in an engine, the engine having a radial center line; and a trunnion connected to the hub. The example trunnion includes a slot to accommodate a first blade, and at least one of the trunnion or the first blade is positioned with at least one of a tilt or a lean with respect to the radial center line to form a pitch axis offset from the radial center line such that the pitch axis is not parallel to or co-linear with the radial center line. The example hub is to rotate the first blade about the pitch axis.

A pitch control system characterized by a hub with at least two blade housings on the hub that are disposed around the hub axis. The blade housings have corresponding blades that engage with them. The blades spiral along housing longitudinal axes toward and away from the hub axis about a segment of helical path to effect a change in the pitch of each blade. One or more elastic members draw the blades toward the hub axis, either directly or indirectly. There are pitch mechanisms effective to facilitate blades to spiral around housing-longitudinal axes. A blade will spiral away from the hub axis when the centrifugal force exerted on the blade exceeds the opposing elastic force in the housing-longitudinal direction (neglecting other forces). Conversely, blades spiral toward the hub axis when said centrifugal force is less than said elastic force. There is an imaginary plane orthogonal to the hub axis. Housing-longitudinal axes have angles with respect to the imaginary plane of not more than 30 degrees.