초록

A funnel strip is added to a rotary airfoil, which utilizes the Bernoulli principle to increase the velocity of air over the suction side of the rotating airfoil to increase the lift. The device is applicable to thrust-producing devices, such as propellers, as well as to wind-powered devices.

대표청구항 ▼

1. A funneled rotary foil comprising:a rotatably mounted hub having an axis of rotation, a plurality of circumferentially spaced blades mounted on said hub so as to extend in a generally radial direction from the hub to a blade tip so as to be rotatable in a plane of rotation about said axis, each s

1. A funneled rotary foil comprising:a rotatably mounted hub having an axis of rotation, a plurality of circumferentially spaced blades mounted on said hub so as to extend in a generally radial direction from the hub to a blade tip so as to be rotatable in a plane of rotation about said axis, each said blade having a cross-section defining an airfoil with a suction side, said airfoil having a leading edge, a trailing edge, and defining a chord extending therebetween, said airfoil increasing gradually in thickness from the leading edge to a point of maximum thickness and decreasing in thickness thereafter to the trailing edge, a fin attached to the blade tip and adapted to block radial flow from the blade tip, and a funnel strip mounted on each of said blades uniformly spaced from the suction side thereof and extending in a generally radial direction along the full length of the blade, said funnel strip having an inlet edge defining a funnel inlet area with the airfoil leading edge and having an outlet edge spaced from the suction side at said point of maximum thickness to define a funnel outlet area, said funnel plate being oriented with respect to the chord so as to scoop in and increase the velocity of air flowing over the suction side of the airfoil, and dimensioned such that the ratio of inlet area to outlet area lies between and including the range of 2:1 to 20:1.