The lengths and/or chords and/or pitches of wind turbine or propeller blades are individually established, so that a first blade can have a length/chord/pitch that is different at a given time to the length/chord/pitch of a second blade to optimize performance and/or to equalize stresses on the system.

A vertical axis wind turbine having a varying length of a rotational diameter includes a plurality of vertical blades connected to a central shaft of a generator, the plurality of blades being provided at equal intervals on the outer circumference side of the central shaft, and each of the blades is provided with at least one support shaft member extending towards the central shaft, and in between each of the support shaft member and the central shaft is provided, respectively, with an elastic telescopic assembly, and each of the elastic telescopic assemblies is respectively driven by the centrifugal force of the blades above a rated speed to drive the support shaft member to extend outwardly, so that the rotation radius of each blade from the central shaft increases as the rotational speed increases.

The lengths and/or chords and/or pitches of wind turbine or propeller blades are individually established, so that a first blade can have a length/chord/pitch that is different at a given time to the length/chord/pitch of a second blade to optimize performance and/or to equalize stresses on the system.

Horizontal axis W/T of low wind speeds of propeller type, bearing a main rotor of three blades (1), while in the space between two successive blades (1) and diametrically opposite to the third, an additional 4th blade (2) also of propeller type but of significantly longer length, is interposed. This additional blade (2) is not permanently coupled but selectively engaged in the system of the W/T at low wind speeds, contributing to the startup and enhancing the energy production. The blade (2) bears diametrically opposite a counterweight (15) to balance the forces developed, and rotates in a plane parallel to the main rotor. The coupling of the blade (2) is preferably made at the stand-by state or at low wind speed operation of the W/T, while the uncoupling will be performed during operating state and at the rated power. The blade (2) after uncoupling, gets in vertical position and remains immobilized attached to the tower.

A wind turbine blade is provided. The wind turbine blade includes a first section and a second section adjacent the first section. At least one of the first section and the second section includes a skin segment and a network of support members disposed within the skin segment. The network of support members is configured for expansion.

A drone with a horizontal rotor includes one or more rotor(s) (115, 116) which rotate in a horizontal plane, each rotor (115, 116) being equipped with one or more rigid or non-rigid blades (120, 121), the blade end being mounted on an electric motor (110, 111) with a propeller.

The lengths and/or chords and/or pitches of wind turbine or propeller blades are individually established, so that a first blade can have a length/chord/pitch that is different at a given time to the length/chord/pitch of a second blade to optimize performance and/or to equalize stresses on the system.