AIRCRAFT WITH VERTICAL TAKE-OFF AND LANDING-VTOL

Abstract

The invention refers to a VTOL aircraft of the type that uses certain aerodynamic phenomena to increase the lifting force and to reduce the thrust/weight ratio. An aircraft 1 uses a propulsion system 2 consisting of four thrust producing elements, two in front 3 and two in rear 4. Each front thrust producing element 3 contains at least one front rotor 5 operated by at least one front electric motor, fixed on a fuselage 10. Each rear thrust producing element 4 contains at least one rear rotor 7 driven by at least a rear electric motor 8, fixed on the fuselage 10. On the fuselage 10 is attached symmetrically a front wing 12. On the fuselage 10 is attached symmetrically a rear wing 13. The wing 12 and 13 are used also in static conditions respectively in take-off and landing.

Claims

1. An aerial vehicle of the type with vertical take-off and landing and/or of the type with ground effect, a vehicle that uses the same propulsion system for both vertical and horizontal flight, propulsion system powered either from a purely electric source, or from a hybrid unit wherein an aircraft (1) uses a propulsion system (2) consisting of at least four thrust producing elements, two in the front (3) and two in the rear (4), symmetrically arranged on both sides of the fuselage (10), and on the fuselage (10), at its front end is symmetrically attached a front wing (12), the front wing (12) being positioned at a fixed angle α between 15° and 80° with the horizontal plane when the aircraft (1) is in a static position, respectively at take-off/landing, and on the fuselage (10), at its rear end is symmetrically attached a rear wing (13), the rear wing (13) being positioned at a fixed angle α between 15° and 80° with the horizontal plane when the aircraft (1) is in a static position, respectively at take-off/landing, and the front wing (12) has at its ends two jet limiters (14), and the rear wing (13) has at its ends two jet limiters (15), and the front wing (12) has an airfoil profile that contains an upper surface (16), a lower surface (17), a leading edge (18) and a trailing edge (19), and the rear wing (13) has an airfoil profile that contains an upper surface (20), a lower surface (21), a leading edge (22) and a trailing edge (23), and the front and the rear thrust producing elements (3) and (4) are positioned on the fuselage (10) between the front wing (12) and the rear wing (13), and the airflow generated by the front and rear traction elements (3) and (4) on the front wing (12) and on the rear wing (21) creates an additional lifting force contributing to the vertical take-off process, even in static conditions.

2. The air vehicle of claim 1 wherein each front thrust producing element (3) contains at least one front rotor (5) driven by at least one front electric motor (6), and each rear thrust producing element (4) contains at least one rear rotor (7) driven by at least one rear electric motor (8), and the rotation plane of the front (5) and rear (7) rotors is considered substantially horizontal when the aircraft (1) is in a static position, respectively at take-off/landing, and the front wing (12) is positioned so that the rotation planes of the front rotors (5) are located in the vicinity of the trailing edge (19) of the front wing (12) and above the upper surface (17), and the rotational planes of the front rotors (5) is positioned in rapport with the front wing (12) at a fixed angle β between 110° and 160°, and the rear wing (13) is positioned so that the rotation planes of the rear rotors (7) are located near the leading edge (22) of the rear wing (13) and below the lower surface (20), and the rotational planes of the rear rotors (7) is positioned in rapport with the rear wing (13) at a fixed angle β between 110° and 160°.

3. The propulsion system of claim 1 wherein the propulsion system (2) produces a greater lifting force than the thrust force developed by the front and rear thrust producing elements (3) and (4).

4. A flight method which create an amplification of the vertical lift wherein in operation, during take off/landing of the aircraft (1), the front electric motors (6) activate the front rotors (5) producing an important depression on the upper surface (17) of the front wing (12) and this amplifies the vertical thrust force, and at the same time, the rear rotors (7) are operated, producing an increased pressure on the lower surface (20) of the rear wing (13) and this amplifies the vertical thrust force.

5. The method of claim 4, wherein the passage from the vertical flight to the horizontal flight of the aircraft (1) is carried out gradually during the transition period by varying the rotation speed of the rear rotors (7) with respect to the front rotors (5), producing the change of the pitch angle of the aircraft (1), and the rear rotors (7) are further accelerated until the front wing (12) and the rear wing (13) reach an optimal angle of attack and the aircraft (1) reaches the horizontal cruise speed, in which case the lift is mainly transferred to the front and rear wings (12) and (13).

6. The air vehicle of claim 2, wherein an aircraft (30), of the amphibious type, uses two main floats (31) attached symmetrically on both sides of a fuselage (32), and the main floats (31) have an elongated cylindrical shape, on the front and the rear of the electric motors (6) and (8) are attached some side floats (33), which are reduced in size compared to the main floats (31).

7. The air vehicle of claim 2, wherein an aircraft (40) uses front and rear wings (12) and (13) which are joined by means of connected straps (41), the connecting straps (41) providing additional protection to the front and rear rotors (5) and (7).

8. The air vehicle of claim 2, wherein an aircraft (50), designed for delivery, uses two elastic strings (51), attached on the fuselage (10) and above it, the two elastic strings (51) securing for transport of a packet (52), which may have different volumes.

9. The air vehicle of claim 2, wherein an aircraft (60), designed for delivery, has a compartment (61) attached below the fuselage (10), and on the fuselage (10) are attached some legs (62), supporting the landing, which have an aerodynamic profile, and various loads are stored in compartment (61) during transportation process.

10. The air vehicle of claim 9, wherein the aircraft (60) transports a parallelepipedic shape container beneath the fuselage (10).

11. The air vehicle of claim 2, wherein an aircraft (70), having rescue missions for injured or sick persons, has attached under the fuselage (10) a stretcher (71), and the stretcher (71) can carry an injured person (72), and the stretcher (71) slides on two guides (73) existent on the fuselage (10), and the stretcher (71) could contain the necessary equipment to support the life of the injured person (72).

12. The air vehicle as in claim 1, characterized in that an aircraft (80) uses a fuselage (81), having at the front an enlarged volume (82) and at the rear a reduced volume (83), and on the fuselage (81) a front wing (84) is fastened to the front side using two flattened supports (85), and the front wing (84) is distanced from the fuselage (81) so that the front air stream can flow between the front wing (84) and the fuselage (81), and on the fuselage (81) a rear wing (86) is fastened to the rear side using two flattened supports (87), and the rear wing (86) is distanced from the fuselage (81) so that the front air stream can flow between the rear wing (86) and the fuselage (81), and on the fuselage (81) are attached some thrust producing elements, two in the front (88) and two in the rear (89), the front thrust producing elements (88) are larger in diameter than the rear thrust producing elements (89).

13. The air vehicle of claim 12, wherein the aircraft (80) is designed for delivery, and the volume (82) contains an internal compartment (92), closed by a cover (93), and in the internal compartment (92) various loads are transported.

14. The air vehicle as in claim 12, characterized in that an aircraft (100), designed for air surveillance, has a multi-scanner (101) attached to the fuselage (81) on its front side, and the multi-scanner (101) contains a number of visual, acoustic and thermal sensors.

15. An operating method wherein, during the forward flight, the rear thrust producing elements (89) produce a depression on the upper surface of the fuselage (81), which decreases the drag.

16. The air vehicle of claim 1, wherein an aircraft (110), with vertical take-off and landing, designed for passenger transport, uses a fuselage (111) which has a cabin (112) positioned in the area of the center of gravity, and the cabin (112) can carry at least one passenger.

17. The air vehicle of claim 1, wherein several aircraft (1) are joined in the area between the jet limiters (4) and (5), forming together a compound structure (24), and the compound structure (24) is used to lift heavy loads.

18. The air vehicle of claim 1, wherein an aircraft (120), designed for various missions, has three pares (121) of thrust producing elements (122), all being attached, symmetrically, side by side from a fuselage (123), this configuration increasing the lift during the take-off and landing phases for heavier loads, and during forward flight a part of thrust producing elements (122) can be deactivated to increase the flight efficiency.

19. The air vehicle of claim 1, wherein an aircraft (130), designed for different missions, uses a third middle wing (131), located between the front thrust producing elements (3) and the rear thrust producing elements (4), and the middle wing (131) has an airfoil shape comprising a lower surface (132), an upper surface (133), a leading edge (134) and a trailing edge (135), and the middle wing (131) being positioned at a fixed angle α between 15° and 80° with the horizontal plane when the aircraft (130) is in a static position, respectively at take-off/landing, and the front thrust producing elements (3) create an increased pressure on the lower surface (132) and simultaneously the rear thrust producing elements (4) create a depression on the upper surface (133), and in forward flight the efficiency of the aircraft (130) is improved even at low speed of the aircraft (130) due to the forced air circulation around the middle wing (131).

20. The air vehicle of claim 1, wherein an aircraft (140), of a drone type, uses at least two fuselages (141) which connect a front wing (142) with a rear wing (143), and on each fuselage (141) are mounted using supports (144) two thrust producing elements, one in the front (145) and one in the rear (146).

21. The air vehicle of claim 20, wherein the aircraft (140) uses three fuselages (141), and during the forward flight, the front and rear thrust producing elements (145) and (146), located in the middle of the aircraft (140), can be deactivated to increase the flight efficiency.

22. The air vehicle of claim 1, wherein an aircraft (150), of a drone type, uses some front fuselages (151) which connect a front wing (152) with a middle wing (153), and the aircraft (150) uses some rear fuselages (154) which connect the middle wing (153) with a rear wing (155), and on each front fuselage (151) and on each rear fuselage (154) is mounted by a support (156) a thrust producing element (157), and the middle wing (153) improves the flight efficiency in both vertical and forward flight.

23. The air vehicle of claim 1, wherein an aircraft (160), designed mainly for delivery, uses four thrust producing elements, two in front (161) and two in rear (162), attached respectively in two front support (163) and in two rear supports (164), and the front supports (165) are attached by some arms (166) on a fuselage (167), and the rear supports (164) are attached on the fuselage (167) by some arms (168), and the fuselage (167) has an airfoil shape, and on each front support (163) is attached a plate (169), and on each rear support is attached a plate (170), and the two plates (169) sustain a front wing (171), and the two plates (170) sustain a rear wing (172), and the profile chord of the fuselage (167) is parallel with profile chords of the front and rear wings (171) and (172), and in forward flight the front and rear wings (171) and (172), respectively the fuselage (167) have the same angle of attack made with the frontal air flow.

24. The air vehicle of claim 23, wherein an aircraft (170), designed for aerial surveillance, has an aerodynamic fuselage (171), and in the top of the fuselage (171) is mounted a multi-scanner (172).

25. The air vehicle of claim 18, wherein an aircraft (180), designed for different missions, have a central fuselage (181), and on both sides of the fuselage (181) are located symmetrically two front rotors (184), two rear rotors (185) and two middle rotors (186), and the middle rotors (186) are more distanced from the fuselage (181) comparing with the front rotors (184) and the rear rotors (185), and the rotational plane of each middle rotor (186) is partially superimposed over the rotational planes of the corresponding front rotor (184) and rear rotor (185).

26. The air vehicle of claim 25, wherein an aircraft (190), which can transport at least one passenger, have a central fuselage (191), and bellow the fuselage (191) is attached a cabin (192), having an aerodynamic shape, and in take-off and landing the aircraft (190) is supported by two front legs (193) and by two rear legs (194), all being attached symmetrically on the cabin (192), and the front and rear legs (193) and (194) have an airfoil profile, aligned with the wing profiles, and the cabin (192) can transport one or more passengers seating on chairs which are inclined through the rear so that when the aircraft is in forward flight phase each chair has a substantially vertical position.

27. The air vehicle of claim 26, wherein the position of each chair can be adjusted by an actuator.

28. The air vehicle of claim 1, wherein an aircraft (200), of reconfigurable type, uses some front and rear wings (201) and (202) joined by means of connected straps (203), and the front wing (201) has at its ends some curved zones (204), oriented backwards and symmetrically disposed, which continue the airfoil profile of the front wing (201), and the rear wing (202) has at its ends some curved zones (205), oriented frontally and symmetrically disposed, which continue the airfoil profile of the rear wing (202).

29. The air vehicle of claim 28, wherein the aircraft (200) uses at least two supplementary wings (206) attached on the connected straps (203), and each supplementary wing (206) has an airfoil profile aligned with the airfoil profile of the front and rear wings (201) and (202).

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Several examples of carrying out are described in relation with the FIGS. 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27 and 28 which represent:

[0024] FIG. 1, an isometric view from the front of an aircraft, of a drone type, in the take-off or landing phase;

[0025] FIG. 2, a longitudinal section through the aircraft from FIG. 1 in the take-off or landing phase;

[0026] FIG. 3, a representation of the flight sequences of the aircraft shown in FIG. 1;

[0027] FIG. 4, an isometric view from the front of the aircraft of FIG. 1 in the transition phase;

[0028] FIG. 5, an isometric view from the front of the aircraft shown in FIG. 1 in the forward flight phase;

[0029] FIG. 6, a representation of the airflow that crosses the aircraft shown FIG. 1 during the forward flight;

[0030] FIG. 7, an isometric view from the front of a compound structure containing three aircraft bodies;

[0031] FIG. 8, a longitudinal section through an amphibious aircraft;

[0032] FIG. 9, an isometric view from the front of an aircraft with joined wings;

[0033] FIG. 10, an isometric view from the front of a delivery aircraft with a package stored above the fuselage;

[0034] FIG. 11, a side view of a delivery aircraft with a package stored under the fuselage;

[0035] FIG. 12, a side view of an air rescue aircraft;

[0036] FIG. 13, an isometric view from the front of an aircraft with six rotors in forward flight phase;

[0037] FIG. 14, an isometric view from the front of an aircraft having three parallel wings in forward flight phase;

[0038] FIG. 15, an isometric view from the front of an aircraft having different size rotors, in the take-off or landing phase;

[0039] FIG. 16, an isometric view from the front of the aircraft shown in FIG. 15 in the forward flight phase;

[0040] FIG. 17, an isometric view from the front of an aircraft, of surveillance type, in the phase of take-off or landing;

[0041] FIG. 18, an isometric view from the front of the aircraft shown in FIG. 17 in the forward flight phase;

[0042] FIG. 19, a side view of a passenger aircraft, in the take-off or landing phase;

[0043] FIG. 20, an isometric view from the front of an aircraft with multiple fuselage in forward flight phase;

[0044] FIG. 21, an isometric view from the front of an aircraft with multiple fuselage and three wings in forward flight phase;

[0045] FIG. 22, an isometric view from the front of an aircraft, designed as a delivery drone, having an aerodynamic fuselage in forward flight phase;

[0046] FIG. 23, an isometric view from the rear of the aircraft shown in FIG. 22;

[0047] FIG. 24, an isometric view from the front of an aircraft, designed as a surveillance drone, having an aerodynamic fuselage in forward flight phase;

[0048] FIG. 25, an isometric view from the front of an aircraft having six superimposed rotors, in forward flight phase;

[0049] FIG. 26, an isometric view from the rear of an aircraft for passengers having six superimposed rotors, in forward flight phase;

[0050] FIG. 27, an isometric view from the front of a reconfigurable aircraft having joined wings, in forward flight phase;

[0051] FIG. 28, an isometric view from the front of the aircraft shown in FIG. 27 designed for extended range.

DETAILED DESCRIPTION

[0052] In a first embodiment, an aircraft 1, with vertical takeoff and landing, of a drone type, uses a propulsion system 2 consisting of four thrust producing elements, two in front 3 and two in rear 4 as in FIGS. 1, 2, 3, 4, 5 and 6. Each front thrust producing element 3 contains at least one front rotor 5 operated by at least one front electric motor 6. Each rear thrust producing element 4 contains at least one rear rotor 7 driven by at least a rear electric motor 8. The rotation plane of the front and rear rotors 5 and 7 is considered substantially horizontal or slightly inclined when the aircraft 1 is in a static position. The front electric motors 6 are attached by means of supports 9 on both sides of a fuselage 10. Similarly, the rear electric motors 8 are attached by means of supports 11 on both sides of the fuselage 10. On the fuselage 10, at the front is attached symmetrically a front wing 12. The front wing 12 is positioned at a fixed angle α between 15° and 80° with the horizontal plane when the aircraft 1 is in a static position. On the fuselage 10, at the rear is attached symmetrically a rear wing 13. The rear wing 13 is positioned at a fixed angle α between 15° and 80° with the horizontal plane when the aircraft 1 is in a static position. The front wing 12 has two jet limiters 14 at its ends. The rear wing 13 has two jet limiters 15 at its ends. The jet limiters 14 and 15 limits the flow developed by the front and rear rotors 5 and 7. The front wing 12 uses an aerodynamic profile which has a lower surface 16, an upper surface 17, a leading edge 18 and a trailing edge 19. The rear wing 13 uses an aerodynamic profile which has a lower surface 20, an upper surface 21, a leading edge 22 and a trailing edge 23. The front wing 12 is so positioned that the rotational planes of the front rotors 5 are located near the trailing edge 19 and above the upper surface 17. The rotational planes of the front rotors 5 is positioned in rapport with the front wing 12 at a fixed angle β between 110° and 160°. The rear wing 13 is so positioned that the rotation planes of the rear rotors 7 are located near the leading edge 22 and below the lower surface 20. The rotational planes of the rear rotors 7 is positioned in rapport with the rear wing 13 at a fixed angle β between 110° and 160°. In operation, when taking off/landing, respectively when the front electric motors 6 are activated, the front rotors 5 produce a major depression on the upper surface 17 of the front wing 12 and this contributes to increase the vertical thrust force. At the same time, the rear rotors 7 are operated which produce an increased pressure under lower surface 20 of the rear wing 13 and this contributes to the increase the vertical thrust force, which corresponds to the position 1a of the aircraft 1 shown in FIG. 3. The transition from the vertical flight to the horizontal flight is gradually performed during the transition period by varying the rotation speed of the rear rotors 7 with respect to the front rotors 5, which produces the change of the pitch angle of the aircraft 1 and corresponds to the position 1b of the aircraft 1 from the FIG. 3. The rear rotors 7 are further accelerated until the front wing 12 and the rear wing 13 reach an optimal angle of attack and the aircraft 1 reaches the horizontal cruise speed. In this case, the lift is transferred mainly to the front wings 12 and the rear wing 13 which corresponds to a position 1c of the aircraft 1 shown in FIG. 3. The air flow direction during the forward flight period inside the propulsion system 2 is represented in FIG. 6. In this case it is observed that the operation of the front and the rear wings 12 and 13 is those for blown wings, the airflow being further accelerated on their aerodynamic surfaces by the front and rear rotors 7. The flying path control is performed, as for a quad-rotor drone, by the variation of the rotational speed of the rotors located on the left side in comparison with those located on the right side of the aircraft 1, or vice versa. For an even more precise control of aircraft 1, certain aerodynamic control surfaces (not shown) can be used, such as, for example, flaps.

[0053] In another embodiment several aircraft 1 structures are joined between jet limiters 4 and 5 forming together a compound structure 24, as shown in FIG. 7. This compound structure 24 can be used to lift heavy loads.

[0054] In another embodiment, derived from shown in FIG. 1, an aircraft 30, of the amphibious type uses two main floats 31 attached on both sides of a fuselage 32, as shown in FIG. 8. The main floats 31 may could have an elongated cylindrical shape. On the front and the rear of the electric motors 6 and 8 are attached some side floats 33, which are reduced in size compared to the main floats 31. Using the main floats 31 and the side floats 33 the aircraft 30 can take-off and land from and on the water.

[0055] In another embodiment, derived from that of FIG. 1, an aircraft 40 uses front and rear wings 12 and 13 joined by means of connected straps 41, as shown in FIG. 9. The connected straps 41 offer additional protection to the front and rear rotors 5 and 7. In operation the connected straps 41 also avoid the dispersion of the air flow on the sides of the aircraft 40.

[0056] In another embodiment, derived from that of FIG. 1, an aircraft 50, used for delivery, has attached on the fuselage 10, specifically positioned above fuselage 10, two elastic strings 51, as shown in FIG. 10. The elastic strings 51 can secure for transport of a packet 52, which may have different volumes.

[0057] In another embodiment, derived from that of FIG. 1, an aircraft 60, used for delivery, has fastened below the fuselage 10 a compartment 61, as shown in FIG. 11. On the fuselage 10 are attached legs 62, which support the landing and which have an aerodynamic profile. Various loads can be stored in the compartment 61. In another embodiment, the compartment 61 is replaced by a parallelepipedic container.

[0058] In another embodiment, derived from that of FIG. 1, an aircraft 70, with a mission transporting injured or sick persons, has attached below the fuselage 10 a stretcher 71, as shown in FIG. 12. The stretcher 71 can carry an injured person 72. The stretcher 71 slides on two guides 73 existent on the fuselage 10. The stretcher 71 could contain the necessary equipment to support the life of the injured person 72.

[0059] In another embodiment, derived from that of FIG. 1, an aircraft 120, designed for various missions, has three pares 121 of thrust producing elements 122, all being attached, symmetrically, side by side from a fuselage 123, as is shown in the FIG. 13. This configuration increases the lift during the take-off and landing phases to accommodate heavier loads. During forward flight some of the thrust producing elements 122 can be deactivated in order to increase the flight efficiency. Also this configuration improves the redundancy level.

[0060] In another embodiment, derived from that of FIG. 1, an aircraft 130, designed for various missions, uses a third middle wing 131, located between the front thrust producing elements 3 and the rear thrust producing elements 4, as is shown in FIG. 14. The middle wing 131 has an airfoil shape comprised of a lower surface 132, an upper surface 133, a leading edge 134 and a trailing edge 135. In this configuration a supplementary lift is obtained in take-off and landing phases because the front thrust producing elements 3 create an increased pressure on the lower surface 132. Simultaneously the rear thrust producing elements 4 create a depression on the upper surface 133. Also in forward flight the efficiency is improved even at low speed of the aircraft 130 due to the forced air circulation around the middle wing 131.

[0061] In another embodiment, an aircraft 80, of delivery type, uses a fuselage 81, having an enlarged volume 82, at the front and a reduced volume 83, at the rear, as shown in FIGS. 15 and 16. On the fuselage 81 is attached to the front a front wing 84 using two flattened supports 85. The front wing 84 is distanced from the fuselage 81 so that the front air stream can flow between the front wing 84 and the fuselage 81. On the fuselage 81 a rear wing 86 is attached using two flattened supports 87. The rear wing 86 is distanced from the fuselage 81 so that the front stream can flow between the rear wing 86 and the fuselage 81. Several thrust producing elements are attached on the fuselage 81, two in the front 88 and two in the rear 89. The front thrust producing elements 88 are larger in diameter than the rear thrust producing elements 89, due to the fact that the center of gravity of the aircraft 80 is transferred more towards the front. The front wing 84 has two jet limiters 90 at the ends. The rear wing 86 has two jet limiters 91, placed at the end of the rear thrust producing elements 89. The enlarged volume 82 contains an internal compartment 92, which can be closed by a cover 93. In the internal compartment 92 various loads can be transported. During the operation, the rear thrust producing elements 89 create a depression on the upper surface of the fuselage 81, which reduce the drag.

[0062] In another embodiment derived from that FIG. 14, an aircraft 100, designed for aerial surveillance, has a multi-scanner 101 attached to the front side of the fuselage 81 as is shown in FIGS. 17 and 18. The multi-scanner 101 has could incorporate a number of visual, acoustic and thermal sensors.

[0063] In another embodiment, a passenger aircraft 110, with vertical take-off and landing, uses a fuselage 111 which has a cabin 112, positioned in the center of gravity area, as is shown in FIG. 19. The cabin 112 can carry at least one passenger. The aircraft 110 can also be used as a ground-effect vehicle that can fly at a low height above a liquid or solid surface with high efficiency.

[0064] In another embodiment, an aircraft 140, of a drone type, uses several fuselages 141, more specifically three fuselages 141 in this example, which connect a front wing 142 with a rear wing 143, as shown in FIG. 20. On each fuselage 141 two thrust producing elements 144 are mounted using supports, one in the front 145 and one in the rear 146. The version with three fuselages 141 has an improved redundancy. In operation during forward flight the front and rear thrust producing elements 145 and 146 located in the middle section of the aircraft 140 can be deactivated to increase the flight efficiency.

[0065] In another embodiment, derived from that of FIG. 20, an aircraft 150, of a drone type, uses several front fuselages 151 which connect a front wing 152 with a middle wing 153, as shown in the FIG. 21. Similarly, the aircraft 150 uses several rear fuselages 154 which connect the middle wing 153 with a rear wing 155. On each front fuselage 151 as well on each rear fuselage 155 a thrust producing element 157 is mounted by means a support 156. The middle wing 153 improves the flight efficiency in both vertical and forward flight.

[0066] In another embodiment, an aircraft 160, designed mainly for delivery, uses four thrust producing elements, two in front 161 and two in rear 162, secured by two front supports 163 and respectively by two rear supports 164, as shown in FIGS. 22 and 23. The front supports 163 are attached on the fuselage 167 using arms 166. The rear supports 164 are attached on the fuselage 167 using arms 168. The fuselage 167 has an airfoil shape. On each front support 163 is attached a plate 169. On each rear support 164 is attached a plate 170. The two plates 169 sustain a front wing 171. The two plates 170 sustain a rear wing 172. The profile chord of the fuselage 167 is parallel with profile chords of the front and rear wings 171 and 172. During the forward flight the fuselage 167 will have the same angle of attack made with the frontal air flow as the front and rear wings 171 and 172. Because of this configuration, in forward flight, the drag of the aircraft 160 is minimum.

[0067] In another embodiment derived from that of the FIG. 22, an aircraft 170, of aerial surveillance, has an aerodynamic fuselage 171, as in the FIG. 24. In the top of the fuselage 171 is mounted a multi-scanner 172. The multi-scanner 172 has incorporated a number of visual, acoustic and thermal sensors.

[0068] In another embodiment, derived from that of FIG. 13, an aircraft 180, designed for various missions, have a central fuselage 181 which supports a front wing 182 and a rear wing 183, as is shown in the FIG. 25. On both sides the fuselage 181 are located symmetrically two front rotors 184, two rear rotors 185 and two middle rotors 186. The middle rotors 186 are more distanced from the fuselage 181 when compared to the front rotors 184 and the rear rotors 185. The rotational plane of each middle rotor 186 is partially superimposed over the rotational planes of the corresponding front rotor 184 and rear rotor 185. This configuration reduces the size of the aircraft 180 and increases the air flow by approximately 5%.

[0069] In another embodiment, derived from that of FIG. 25, an aircraft 190, which can transport at least one passenger, has a central fuselage 191, as is shown in FIG. 26. Bellow the fuselage 191 is attached a cabin 192, having an aerodynamic shape. In take-off and landing phases the aircraft 190 is supported by two front legs 193 and by two rear legs 194, all being attached symmetrically on the cabin 192. The front and rear legs 193 and 194 have an airfoil profile, aligned with the wing profiles. The cabin 192 can transport one or more passengers seating on chairs (not shown) which are inclined through the rear so that when the aircraft is in forward flight phase each chair has a substantially vertical position. Also the position of each chair can be adjusted by an actuator (not shown).

[0070] In another embodiment, derived from that of FIG. 9, an aircraft 200, of reconfigurable type, uses some front and rear wings 201 and 202 joined by means of connected straps 203, as shown in FIGS. 27 and 28. The front wing 201 has at its end curved zones 204, oriented backwards and symmetrically disposed, which continue the airfoil profile of the front wing 201. The rear wing 202 has at its ends some curved zones 205, oriented frontally and symmetrically disposed, which continue the airfoil profile of the rear wing 202. This configuration improves the efficiency of the aircraft 200 and creates a continuous rigid structure. The range of the aircraft 200 can be extended by attaching at least two supplementary wings 206 on the connected straps 203, as is shown in the FIG. 28.

[0071] Each supplementary wing 206 has an airfoil profile aligned with the airfoil profile of the front and rear wings 201 and 202.

[0072] All the described variants can have curved wings as described in FIG. 27.

[0073] All the described variants can have in an all-electric version a battery pack as power source for propulsion.

[0074] All the described variants can have in a hybrid-electric version a hybrid-electric power source for propulsion.

[0075] Any combination between the elements of this disclosure will be considered as being part of the description and of the claims.