Abstract: A hydrofoil sailboat comprises forward and aft surface piercing hydrofoils and an asymmetrical wingsail. Both hydrofoils have an inverted arch configuration and have a cross-section which is approximately a circular segment. The wingsail has a reversible asymetry, is carried on a cantilevered rotatable mast and includes a sail sock that is highly tensioned between a single top frame member and a bisectional articulated bottom frame member, the asymmetry of the wingsail being defined by the relative position of the bottom frame member sections.

Abstract: A rotary wing device adapted to be rotated about its longitudinal axis and to be propelled forwardly with its longitudinal axis having a small upward pitch angle relative to the forward flight direction in order to generate an upward lifting force on the device. The rotary wing device has a plurality of laterally spaced-apart cylindrically disposed wing segments. Preferably, the wing segments are parallel to each other, are parallel to the longitudinal axis of the device, and have streamlined edges. Preferably, the wing segments are mounted for rotation about the longitudinal axis of the device by front and rear mounting rings which engage and stabilize the front and rear tips of the wing segments. The mounting rings are perpendicular to the wing segments and have streamlined edges. The preferred embodiment is a throwable aerial toy having its center of mass located on the forward half of its longitudinal axis and being statically and dynamically balanced relative to said longitudinal axis.

Abstract: A microscope which has a substantially cylindrical shape, the cylinder being hollow to house insects and the like being viewed, the viewing end of the cylinder including a magnifying lens for viewing the insects, and the walls of the cylinder having Fresnel grooves for increasing the illumination of the insects being viewed.

Abstract: A hanging birdhouse having an aerodynamic asymmetrical teardrop shape. The birdhouse is turned by the wind so that the entry hole always faces the downwind direction. Ventilation slots are provided adjacent to the entry hole so that the wind produces forced ventilation of the birdhouse.