Continuum Dynamics, Inc.

Daniel A Wachspress

Alan J Bilanin

Glen R Whitehouse

Alexander H Boschitsch

Todd R Quackenbush

A wind-driven power generating system with a hybrid wind turbine mounted on a floating platform that heels relative to horizontal in the presence of a prevailing wind. The hybrid turbine has a turbine rotor with at least two rotor blades, each mounted to a turbine shaft by at least one strut, and the system is configured so that the shaft forms a predetermined non-zero operating heel angle relative to vertical in the presence of a prevailing wind at a predetermined velocity. The blades and struts are airfoils with predetermined aerodynamic characteristics that generate lift forces with components in the direction of rotation around the shaft of the blades and struts at the operating heel angle to drive an electrical generator carried by the platform. The system can be designed to generate maximum power at the predetermined heel angle or essentially constant power over a range of heel angles.

Hybrid vertical/horizontal axis wind turbine for deep-water offshore installations

A rotor blade has a local geometric twist angle &thgr;&equals;&fnof;(r/R), with R being the blade span and r being the distance along the blade span from the axis of rotation. The blade has an inner region between an (r/R) &equals;0.20&plusmn;0.04 and a transition point at (r/R) &equals;0.75&plusmn;0.04, wherein &thgr; at (r/R) has a positive value and is greater than or equal to &thgr; at (r/R) . A blade tip region includes a first portion between (r/R) and (r/R) >(r/R) , wherein &thgr; continuously decreases from &thgr; to &thgr; at (r/R) , and &Dgr;&thgr; &equals;&verbar;&thgr; &minus;&thgr; &verbar;>3&deg;, and a second portion between (r/R) and the blade tip, wherein &thgr; continuously increases from &thgr; to &thgr; at the tip, and &Dgr;&thgr; &equals;&verbar;&thgr; &minus;&thgr; &verbar; is at least about 3&deg; and no greater than about 20&deg;. This geometry pushes the vortex trailed by the blade tip away from the blade and thus increases blade performance. In a preferred tiltrotor blade embodiment, &Dgr;&thgr; &equals;&verbar;&thgr; &minus;&thgr; &verbar;&equals;32.5&deg;&plusmn;7.5&deg;, &thgr; continuously decreases from (r/R) to (r/R) , (r/R) &equals;0.91&plusmn;0.04, &Dgr;&thgr; &equals;7.5&deg;&plusmn;2.5&deg;, and &Dgr;&thgr; &equals;10&deg;&plusmn;6&deg;. In a preferred helicopter blade embodiment, &Dgr;&thgr; &equals;&verbar;&thgr; &minus;&thgr; &verbar;&equals;20&deg;&plusmn;5&deg;, &thgr; continuously decreases from (r/R) to (r/R) , (r/R) &equals;0.94&plusmn;0.04, &Dgr;&thgr; &equals;5&deg;&plusmn;2&deg;, and &Dgr;&thgr; is from about 3&deg; to about 10&deg;. Another embodiment of the invention uses adjustable flaps to control &thgr;&equals;&fnof;(r/R) in an inboard region of a helicopter blade to optimize performance in hover and forward flight regimes.

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Yardley, PA, United States of America

Daniel A Wachspress