초록 ▼

A hovering or VTOL aircraft with a propulsion unit using a fan in a shroud whose upper end is toroidally shaped and rotationally symmetrical with a convex curvature with a radius of curvature between 0.2 rf and 1 rf from a location 1.4 rf upstream of the blade plane to a location 0.2 rf downstream t

A hovering or VTOL aircraft with a propulsion unit using a fan in a shroud whose upper end is toroidally shaped and rotationally symmetrical with a convex curvature with a radius of curvature between 0.2 rf and 1 rf from a location 1.4 rf upstream of the blade plane to a location 0.2 rf downstream thereof. The blade, whose tip radius is rf has a twist at least from a range of ±0.25 rf around a mean radius between hub and tip to the tip such that the airflow velocity through the meridian increases outwardly from the hub of the fan toward the periphery of the fan.

대표청구항 ▼

A propulsion apparatus for generating vertical lift in an aircraft, comprising: a fan shroud defining a substantially vertical airflow passage having an axis, an upper inlet end and a lower outlet end, said passage being rotationally symmetrical about said axis but differing from a right-circular cy

A propulsion apparatus for generating vertical lift in an aircraft, comprising: a fan shroud defining a substantially vertical airflow passage having an axis, an upper inlet end and a lower outlet end, said passage being rotationally symmetrical about said axis but differing from a right-circular cylinder over its entire length; a fan rotatable in said passage about said axis and having a plurality of generally radial blades where the radial axis of these blades is lying in a plane perpendicular to said axis between said inlet and outlet ends and where these fan blades can be also rotatable around their blade axis for control purposes; a torus-like convexly curved part rotationally symmetrical about said axis and formed on said shroud at said inlet end of said passage, said torus-like convexly curved part extending from a location substantially 1.4 rf upstream of said blades seen radially to a location substantially 0.2 rf downstream of said blades seen axially where rf is a tip radius of said blades measured from said axis to a tip of the blades, said tips of said blades defining a gap with said part which is at most 1/25 of the diameter of said fan; and at least one engine operatively connected with said fan for rotating same, said rotating blades being of airfoil cross section with the angle between the chord lines of the blades and the rotation plane of the fan blades decreasing from the hub of the fan to a radial midsection of the fan blades and increasing from the radial midsection towards the fan tip by an increment (AB) having a value in the range from 0 degrees up to 25 degrees to generate upon rotation of said fan a meridional airflow velocity through said passage which is nonuniform over the radius thereof and increases from a value proximal to said axis to a maximum at the periphery of said passage, said radial midsection of the fan blades being defined as a distance ±0.25rf around a means fan blade radius and as the arithmetic means between fan hub radius and fan tip radius, and the meridional radii of curvature of said torus-like convexly curved part between said locations being 0.2rf to 1rf.