Field of invention

This invention relates to aircraft where the lift is produced by one central ducted fan (rotor in a ring) that expels air downwards to the ground.

The flight direction of this aircraft is controlled by tilting of the aircraft, which produces a horizontal component of the total lift force, which sets the aircraft in lateral horizontal motion in the particular direction.

Background of the invention

The standard arrangement of the air inlet into the rotor of aircraft with vertical take-off and landing that use a central rotor to produce lift is such that air is sucked from the top, which ensures the shortest way of sucked air towards the rotor. However, this arrangement manifests the following disadvantages : Inflow of air from the top may cause damage of the rotor by suctioned objects and birds, especially in aircraft designed for transport of people, which must have a large diameter of the fan rotor. At a high horizontal speed of aircraft with top inflow of air and with a large rotor the aerodynamic efficiency of the rotor is reduced due to uneven action of the sucked air upon the leading and trailing blades, defined with regard to the flight direction, of the rotor. These disadvantages make safe use of aircraft with vertical take-off and landing with top inflow of air difficult for transport of people and limit the achievable horizontal flight speed.

Summary of the invention For the purposes of this description and the patent claims the bottom part of the aircraft refers to the part of the aircraft that faces the surface from which the aircraft starts during its start. The above mentioned disadvantages of the prior art are eliminated by an aircraft with vertical take-off and landing in accordance with the invention, containing a central fan to produce lift by expelling air from the bottom part of the aircraft, where the fan comprises a rotor driven by a motor, the principle of which is that in the bottom part of the aircraft there is at least one inlet for air supply from the outside of the aircraft to the rotor.

According to one of the convenient embodiments the aircraft contains one inlet having the shape of a ring-shaped slot that is coaxial with the vertical axis of the aircraft.

According to another one of the convenient embodiments the aircraft may contain a plurality of inlets located around the vertical axis of the aircraft while individual inlets are separated from each other by radial ribs.

According to another one of the convenient embodiments the aircraft contains a number of directing means arranged around the vertical axis of the aircraft for reception of air expelled from the rotor and controlled directing of this air during its discharge out of the aircraft.

The directing means conveniently comprise directing radial vanes that may be adjusted in a controlled way, for controlled directing of air during its discharge out of the aircraft to control the turning of the aircraft around its vertical axis and tilting of the aircraft around the horizontal axes.

The aircraft further conveniently contains auxiliary radial vanes that can be adjusted in a controlled way, arranged around the vertical axis of the aircraft between the inlets and the rotor for reception of air flow from the inlets and the possibility to change the air angle at which air is discharged from the auxiliary radial vanes to the rotor to create a tilting torque acting upon the aircraft.

The directing means conveniently comprise fixed radial vanes, located between the rotor and the directing radial vanes, for reception of the air expelled from the rotor and its routing to the directing radial vanes, from which this air is discharged out of the aircraft.

According to one of the convenient embodiments the bottom part of the aircraft is fitted with landing gear legs and its top part comprises a cabin covered by canopy that comprises a fixed front part and a rotationally sliding rear part.

As mentioned above, air is sucked into the aircraft from the bottom while the cavity leading the air stream from the inlet to the rotor conveniently has a shape similar to the inverted letter "U" in the radial cross-section.

In the aircraft in accordance with the invention the inflow of air from the bottom prevents suctioning of objects and birds and since during a horizontal flight the aircraft in accordance with the invention is tilted in the flight direction, the rotor inlet at the bottom part of the aircraft is completely screened against the incoming air stream, which ensures even air flow on the rotor blades.

It is convenient to implement control of the flight direction of the aircraft in accordance with the invention through separately controlled adjustable directing radial vanes located under the rotor, i.e. in the air stream flowing out of the rotor. The adjustable directing radial vanes located under the rotor make it possible, depending on the direction and amount of their coordinated movement, to produce a torque around the central axis of the aircraft, by producing a vortex stream at the outlet of the radial blades, which turns the aircraft around the vertical axis, and/or tilting torque around the horizontal axis of the aircraft, through a concentrated, or diffuse stream at the outlet of the radial vanes that tilts the aircraft and sets it in a horizontal flight in the particular direction.

However, the aircraft may also comprise adjustable auxiliary radial vanes that are installed before the rotor, i.e. in the air stream flowing from the inlet towards the rotor. These auxiliary radial vanes, depending on the direction and amount of their coordinated movement, make it possible to produce tilting torque around the horizontal axis of the aircraft, by changing the angle of the air stream towards the rotor in different, especially opposite places, changing the angle of incidence of the air stream onto the rotor blades. This causes a change of distribution of the lift force produced by the rotor, which creates tilting torque that will tilt the aircraft and set it in a horizontal flight in the particular direction. The tilting torque caused by the auxiliary adjustable vanes (installed before the rotor) adds up to the tilting torque produced by the directing vanes (installed under the rotor) .

If the auxiliary adjustable vanes are used to produce the tilting torque, the directing adjustable vanes do not possibly have to be used to produce the tilting torque - in such a case the tilting adjustable vanes are only used to turning the aircraft around its central axis. It is convenient to use the rotationally sliding part of the cabin canopy to provide the entry and exit way into/out of the aircraft in accordance with the invention.

Unlike aircraft with vertical take-off and landing driven by a fan with air inflow from the top the aircraft in accordance with the invention offers higher safety and allows to achieve a higher horizontal speed.

Brief description of drawings

The invention will be further clarified in more detail with the use of examples of its embodiments with a reference to drawings where: fig. 1 presents a general schematic perspective view of an embodiment example of the aircraft in accordance with the invention, fig. 2 shows a cross-section of the embodiment example of the aircraft in accordance with the invention of fig. 1. fig. 3 shows a cross-section of another embodiment example of the aircraft in accordance with the invention where besides the directing radial vanes auxiliary radial vanes are also used. Examples of embodiments of the invention

As shown in fig. 2, in the middle of the cabin of the aircraft 1 there is a rotor 2 that is mounted in a bearing 3 in a rotary way and is driven by the motor 4. The ring 5 is connected to the cover of the motor part 6 with fixed radial vanes 7. The ring 5 is also connected to the fuselage of the aircraft 1, namely with radial ribs 9. Between the ring 5 and the cover of the motor part 6 directing radial vanes 8 are attached in a swivelling way that ensure control of turning of the aircraft 1 around the vertical axis and produce tilting torque for tilting the aircraft 1 around its horizontal axes. The motor 4 and landing gear legs 10 are connected to the cover of the motor part 6. The canopy of the cabin has two parts, a fixed front part and a rotationally sliding rear part. fig. 3 shows a cross-section of another embodiment example of the aircraft 1 in accordance with the invention where besides the directing radial vanes 8 auxiliary radial vanes 13 are also used that are installed in the cavity directing the air from the inlet 11 towards the rotor 2. The auxiliary radial blades 13 are attached in a swivelling way and their swivel can be controlled to influence the angle at which the air is routed to the rotor 2 . Thus, the auxiliary radial vanes 13 (besides the directing radial vanes 8) participate in producing the tilting torque for tiling the aircraft 1 around the horizontal axes.

Wherever the term "convenient" is used for some technical arrangement in the present description, it is meant to designate in a non-limiting way an example of possible arrangements that fall within the scope of the present invention. Similarly, the invention is not limited only to the described and displayed examples of its embodiments, but it also covers all adaptations and modifications that fall within the scope of the attached patent claims.