Flow driven engine

1. An energy conversion system, comprising:

a support rotatable about a first axis orthogonal to a direction of fluid movement;

at least one panel mounted on the support for rotation about a said first axis, the panel having a matrix of flaps respectively mounted in openings on the panel for rotation about multiple horizontal secondary axes;

retaining hardware extending parallel to the secondary axes and across adjacent openings to resist rotation of said flaps during a first portion of a rotation cycle of the support and permitting the flaps to rotate freely during a second portion of said cycle, the panel providing a driving torque during said first portion of the cycle and moving freely to an orientation with minimum fluid resistance during said second portion;

wherein said retaining hardware comprises an abutment on the support for each rotating flap, and

wherein the abutment is retractable to place the rotating flaps in a non-driving mode.

2. The system of claim 1 , comprising a plurality of said panels to provide driving torque during different portions of the cycle of rotation of the support.

3. The system of claim 2 , wherein the panels are distributed circumferentially about said first axis.

4. The system of claim 1 , wherein a flow resistance distribution of each rotating flap is eccentric with respect to its axis of rotation.

5. The system of claim 4 , wherein a mass distribution or a shape of each rotating flap ensures that a center of mass of the rotating flap lays close to its axis of rotation.

6. The system of claim 1 , comprising a plurality of abutments, wherein the abutments are retractable by groups depending on the measured speed of the flow.

7. The system of claim 1 , wherein each flap is substantially planar.

8. The system of claim 1 , wherein the flaps are aerodynamically shaped.

9. The system of claim 1 , comprising a rotating flywheel float coupled to the support to reduce a weight load.

10. The system of claim 9 , wherein the flywheel float comprises a static float to reduce the weight load for offshore installation.

11. The system of claim 1 , wherein the flaps are installed on or near an offshore platform.

12. The system of claim 1 , comprising a parallelogram suspension coupled to the support to compensate for tidal and other long waves; wherein the suspension is decoupleable to lower the support below a surface.

13. The system of claim 1 , comprising a hydraulic transmission coupled to the support.

14. The system of claim 1 , comprising a plurality of turbines combining their outputs with a hydraulic collector.

15. The system of claim 1 , wherein the flaps form a vertical axis wind turbines (VAWT), comprising a Horizontal Axis Wind Turbine (HAWT) to form a Hybrid HAWT/VAWT system to optimize efficiency over a range of wind speeds.

16. The system of claim 1 , comprising a platform extension extending to the support away from a small platform to mount a large turbine for the small platform.

17. A method for generating energy, comprising:

providing a support rotatable about a first axis orthogonal to a direction of fluid movement;

mounting at least one panel on the support for rotation about said first axis, the panel having a matrix of flaps respectively mounted in openings on the panel for rotation about multiple horizontal secondary axes;

providing retaining hardware extending parallel to the secondary axes and across adjacent openings to resist rotation of said flaps during a first portion of a rotation cycle of the support and permitting the flaps to rotate freely during a second portion of said cycle, the panel providing a driving torque during said first portion of the cycle and the flaps moving freely to an orientation with minimum fluid resistance during said second portion;

wherein said retaining hardware comprises an abutment on the support for each rotating flap, and

wherein the abutment is retractable to place the rotating flaps in a non-driving mode.

18. The method of claim 17 , comprising providing driving torque with a plurality of said panels during different portions of the cycle of rotation of the support.