This invention is an auxiliary wind turbine featuring an aperture. In the preferred embodiment, the device itself is stationary, and mounts onto host objects that move such as wind turbine blades or vehicles. The Aperture Turbine may be oriented on the host object in a plurality of locations to enhance and maximize the intake of kinetic energy from the air moving around and through the Aperture Turbine when in use.

A method of attaching a tip extension to a wind turbine blade is described. The method comprises: fitting the tip extension over a tip end of the blade such that an overlap region is defined between an outer surface of the blade and an inner surface of the tip extension; and supplying adhesive to the overlap region via one or more holes provided in the tip extension to bond the tip extension to the blade. In preferred embodiments, adhesive dams are provided in the overlap region to define bond cavities and constrain the adhesive within the bond cavities. An assembly comprising a wind turbine blade and a tip extension bonded thereto is also described.

A vertical axis turbine having a first rotor and at least one second rotor, the first rotor being configured to rotate around a first rotation axis that is vertical or more vertical than horizontal. The first rotor may be configured to be driven and/or rotated by wind or water flow. The at least one second rotor is provided on or coupled to the first rotor such that the first rotor is operable to move the second rotor upon rotation of the first rotor. The second rotor is operable to drive a power take off system. Each second rotor rotates around a respective second rotation axis that may be angled or perpendicular to the first rotation axis of the first rotor. The first and second rotors are configured so that the power take-off system can be driven without the need for a gearbox.

A method of attaching a tip extension to a wind turbine blade is described. The method comprises: fitting the tip extension over a tip end of the blade such that an overlap region is defined between an outer surface of the blade and an inner surface of the tip extension; and supplying adhesive to the overlap region via one or more holes provided in the tip extension to bond the tip extension to the blade. In preferred embodiments, adhesive dams are provided in the overlap region to define bond cavities and constrain the adhesive within the bond cavities. An assembly comprising a wind turbine blade and a tip extension bonded thereto is also described.

A wind generator, comprising: at least one wind wheel which is mounted to be rotatable around a rotational axis, and which has one or more blades or other wind-guiding surfaces for converting flow energy of wind into rotational energy, at least one generator, which is coupled to a hub or shaft of the wind wheel or to an output shaft of a gear connected thereto, for converting the rotational energy into electrical energy, wherein a center of gravity of the wind wheel, together with a hub and rotor shaft and rotatable parts which are coupled to the hub or rotor shaft and rotate around the same rotational axis, is translationally movable in a horizontal or approximately horizontal direction, characterized in that: the generator is either a direct current generator or is on its output side coupled to a rectifier to provide the electrical energy as direct current, and at least one energy storage is coupled to a direct current output of the generator or of the rectifier for receiving and storing the electrical energy.

A wind turbine with a vertical axis includes a base; a central shaft; and a rotor operationally engaging the central shaft. The rotor is rotatable relative the central shaft, and coaxial therewith about the vertical axis. The rotor includes a plurality of pairs of blades, each pair of blades including a larger outer blade and a smaller inner blade. The outer and inner blades define at least one diverting and distribution channel for a laminar flow effect induced by the inner blade against the outer blade, involving a delay in the detachment of the air flow from the edge of the surface of the outer blade, allowing the turbine to operate in wind having a speed about 2 m/s.

The invention relates to a turbine comprising a primary rotor, for positioning in a fluid flow, having a primary rotor blade rotatable around a primary rotor axis under influence of the fluid flow acting on the primary rotor blade and extending from the primary rotor axis along a longitudinal axis to a free outer end of the primary rotor blade. The primary rotor blade is provided near the free outer end with a secondary rotor. The secondary rotor has a secondary rotor blade rotatable around a secondary rotor axis in response to a rotation of the primary rotor blade around the primary rotor axis. The secondary rotor axis is substantially transverse to the longitudinal axis of the primary rotor blade. The secondary rotor axis is also substantially transverse to the primary rotor axis. The turbine is characterised in that the secondary rotor axis is positioned offset from the longitudinal axis of the primary rotor blade.

Efficiency of a horizontal axis wind/water turbine (HAWT) is increased by the addition of a secondary blade associated with each main blade. The secondary blade is preferably a blade segment paralleling the main blade only in the outer reach of the main blade. The secondary blade travels rotationally ahead of the main blade and axially behind it, in an area in which air has not been disturbed by the main blades and in which disturbance of air by the secondary blade is not seen by the main blades. In one embodiment the secondary blade is carried by its associated main blade. In another embodiment, the secondary blades are carried by a ring or wheel which rotates with the main blades and the axle to which they are attached.

The invention relates to a turbine comprising a primary rotor, for positioning in a fluid flow, having a primary rotor blade rotatable around a primary rotor axis under influence of the fluid flow acting on the primary rotor blade and extending from the primary rotor axis along a longitudinal axis to a free outer end of the primary rotor blade. The primary rotor blade is provided near the free outer end with a secondary rotor. The secondary rotor has a secondary rotor blade rotatable around a secondary rotor axis in response to a rotation of the primary rotor blade around the primary rotor axis. The secondary rotor axis is substantially transverse to the longitudinal axis of the primary rotor blade. The secondary rotor axis is also substantially transverse to the primary rotor axis. The turbine is characterised in that the secondary rotor axis is positioned offset from the longitudinal axis of the primary rotor blade.

A free stream fluid kinetic energy conversion device combines a large diameter freewheeling primary rotor with small diameter secondary power takeoff rotors placed within the lift induced blade tip vortices of the primary rotor. This enables use of high rotational speed generating units and avoids diseconomy of scale in gearbox expense. The device partially recovers otherwise lost blade tip vortex energy. The freewheeling primary rotor transmits no reaction torque to the support structure. Resilient buoyant tether deployment accommodates transient eddy induced structural loads.