Patent ID: 7275712

Claim:
A vehicle, comprising: a vehicle frame; a duct carried by said vehicle frame with the longitudinal axis of the duct perpendicular to the longitudinal axis of the vehicle frame; propeller rotatably mounted within said duct about the longitudinal axis of the duct to force an ambient fluid therethrough from its inlet at the upper end of the duct through its exit at the lower end of the duct, and thereby to produce an upward lift force applied to the vehicle; and a plurality of parallel, spaced vanes mounted to and across the inlet end of the duct about axes perpendicular to said longitudinal axis of the duct, said vanes being configured to produce a desired horizontal force component to the lift force applied to the vehicle, wherein said vanes include: a first group of parallel vanes extending across one half of the inlet of said duct at a predetermined acute angle with respect to the longitudinal axis of the vehicle frame; and a second group of parallel vanes extending across the remaining half of the inlet end of said duct at said predetermined angle, but in the opposite direction, with respect to the longitudinal axis of the vehicle frame, wherein said first and second groups of vanes are configured to produce a desired net control force in addition to the lift force applied to the vehicle.