1. A Vertical Take-Off and Landing ("VTOL") aircraft comprising a plurality of electrically powered ducted fans wherein an aircraft (1) uses a modular propulsion system (7) consisting of three multiple propeller having a linear shape.

2. An aircraft as claimed in claim 1 wherein two multiple propellers (8) are located in the front of the aircraft (1) and one multiple propeller (9) is located at the rear side of the aircraft (1).

3. An aircraft as claimed in claim 1 wherein an aircraft (80) uses a modular propulsion system (85) comprising one multiple propeller (85), located in the front of the aircraft (80), and two multiple propellers (87), located at the rear side of the aircraft (80).

4. An aircraft as claimed in claim 2 wherein:

the aircraft (1) has a fuselage (2) and some wings (3), extensible, located side by side from the fuselage (2), and

the fuselage (2) contains a cockpit (4), which has an aerodynamic shape and is extended with two members (5), distanced by an opening (6), and

each wing (3) contains a fixed part (16) and mobile part (17) which can be retracted inside of the fixed part (16), and

at the rear part of the aircraft (1), fixed on the members (5), there are two vertical stabilizers (18) which support a horizontal stabilizer (19), of the inversed type.

5. An aircraft as claimed in claim 4 wherein:

the two multiple propellers (8) are rotatable mounted on the cockpit (4) in the front of the wings (3), side by side from the fuselage (2), and

the multiple propeller (9) is located in the opening (6) and is rotatable mounted between the two members (5), and

each multiple propeller (8) or (9) has a main axis parallel with the middle plane of the aircraft (1), and

in the middle area of each multiple propeller (8) is fixed a shaft (12) which can be rotated solidary with the multiple propeller (8), and

in the middle area of the multiple propeller (9) are fixed two shaft (13) which can be rotated solidary with the multiple propeller (9), and

the shafts (12) or (13) can be acted by some actuators, and in the front of each multiple propeller (8) or (9) is fixed a wheel (14) by means a bracket (15), and

at the rear of the multiple propeller (8), aligned with the multiple propellers (8) are rotatable mounted two flaps (20) on the fuselage (2), and

at the rear of the multiple propeller (9), side by side, are rotatable mounted two flaps

(21) on the members (5), and

the flaps (20) and (21) are acted by actuators.

6. An aircraft as claimed in claim 5 wherein:

in operation, during take-off from a limited space, the mobile parts (17) of the wings (3) are retracted in the interior of the fixed parts (16) so that to minimize the footprint of the aircraft (1) and in the same time the multiple propellers (8) and (9) are in horizontal position and their air streams are vectored through down, and

when the aircraft (1) arrives at a certain befitting altitude the mobile parts (17) are extended to their maximum lengths being prepared to obtain the maximum aerodynamic lift in forward flight, and

in the transition from the vertical lift to the forward flight the multiple propellers (8) and (9) are acted in an inclined position which begins to push the aircraft (1) in forward flight, and in proportion as the horizontal speed of the aircraft (1) increases, the lift begins to be achieved exclusively by the wings (3), helped by the horizontal stabilizer (19), and

when aircraft (1) arrive near to the cruise speed the multiple propellers (8) and (9) arrive in vertical position and the air streams are horizontally oriented, and concomitantly the wings (3) and the horizontal stabilizer (19) sustain completely the aircraft (1).

7. An aircraft as claimed in claim 6 wherein:

in operation with low speed, near the ground, the control of the aircraft (1) is achieved by using the flaps (20), respectively (21) which can be oriented so that to cancel the influence of the side wind or can be used to make the rotation of the aircraft (1) around the vertical axis, and

in operation at high speed the aircraft control is made by changing the inclination angle of the multiple propellers (8) reported to the inclination angle of the multiple propeller (9), respectively by varying the rotation speed of electric motors which act the rotors, and

in the case of partial failure of the modular propulsion system (7), the aircraft (1) can glide with the help of the wings (3) as a fixed wing aircraft and can land on an airport runway using the wheels (14), and

the aircraft (1) can take-off and land from the water due to the natural floatability of its fuselage (2).

8. An aircraft as claimed in claim 3 wherein: the aircraft (80) comprises a fuselage (81), divided in two semi-bodies (82) which are united by a bridge (83), having in cross section an aerodynamic shape, and

on the aircraft (80) are fixed some wings (84), extensible, located side by side from the fuselage (81), and

each wing (94) contains a fixed part (92) and mobile part (93) which can be retracted inside of the fixed part (92), and

at the rear part of the aircraft (80), fixed on the semi-bodies (82), there are two vertical stabilizers (94) which support a horizontal stabilizer (95).

9. An aircraft as claimed in claim 8 wherein:

the multiple propeller (86) is rotatable mounted between the two semi-bodies (82) in the front of the aircraft (80), and other multiple propellers (87) are located at the rear side of the aircraft (80), rotatable mounted side by side from the fuselage (81), respectively behind the wings (84), and

in the middle area of the multiple propeller (86) are fixed two shafts (88) which can be rotated solidary with the multiple propeller (86), and

in the middle area of each multiple propeller (87) is fixed one shaft (89) which can be rotated solidary with the multiple propeller (87), and

the shafts (88) or (89) can be acted by some actuators, and

in the front of each multiple propeller (86) or (87) is fixed a wheel (90) by means a bracket (91), and

aligned with the multiple propellers (86) and side by side are rotatable mounted two flaps (97) on the fuselage (81), and

at the rear of the multiple propellers (87) are rotatable mounted two flaps (97) on the semi-bodies (82), and

the flaps (97) and (98) are acted by actuators.

10. An aircraft as claimed in claim 9 wherein:

in operation, during take-off from a limited space, the mobile parts (93) of the wings (84) are retracted in the interior of the fixed parts (92) so that to minimize the footprint of the aircraft (80) and in the same time the multiple propellers (86) and (87) are in horizontal position and their air streams are vectored through down, and

when the aircraft (80) arrives at a certain befitting altitude the mobile parts (93) are extended to their maximum lengths being prepared to obtain the maximum aerodynamic lift in forward flight, and

in the transition from the vertical lift to the forward flight the multiple propellers (86) and (87) are acted in an inclined position which begins to push the aircraft (80) in forward flight and in proportion as the horizontal speed of the aircraft (80) increases, the lift begins to be achieved exclusively by the wings (84), helped by the horizontal stabilizer (95), and

when aircraft (80) arrives near to the cruise speed, the multiple propellers (86) and (87) arrive in vertical position and the air streams are horizontally oriented, and

concomitantly the wings (84) and the horizontal stabilizer (95) sustain completely the aircraft (80).

11. An aircraft as claimed in claim 10 wherein:

in operation with low speed, near the ground, the control of the aircraft (80) is achieved by using the flaps (97), respectively (98) which can be oriented so that to cancel the influence of the side wind or can be used to make the rotation of the aircraft 1 around the vertical axis, and

in operation at high speed the aircraft control is made by changing the inclination angle of the multiple propeller (86) reported to the inclination angle of the multiple propellers (87), respectively by varying the rotation speed of electric motors which act the rotors, and in the case of partial failure of the modular propulsion system (85), the aircraft (80) can glide with the help of the wings (84) as a fixed wing aircraft and can land on an airport runway using the wheels (90), and

the aircraft (80) can take-off and land from the water due to the natural floatability of its fuselage (81).

12. A multiple propeller wherein:

a multiple propeller (50) contains a number of ducts (51) , in each duct (51) working two counter-rotating rotors (52), respectively (53), and

the rotor (52) is acted in rotation motion by an electric motor (54) and the rotor (53) is acted in rotation motion by an electric motor (55), and

the ducts (51) are tangent each other and take shape together a duct block (56), and the air stream passing through the ducts (51) is increased due to the mounting in series of the rotors (52), respectively (53).

13. A multiple propeller wherein:

a multiple propeller (60), contains a number of ducts (61), inside of each duct (61) working a rotor (62) located in the lower side of the duct (61), and the rotor (62) is acted in rotation motion by an electric motor (63), and

each duct (61) is fixed by means some brackets (65) inside of another duct (64), concentric with a duct (61), the walls of the duct (64) showing in a cross section an aerodynamic shape, and

the ducts (64) are tangent each other and take shape together a duct block (66), and inside of each duct (64) works a rotor (67) acted in rotation motion by an electric motor (68), and

the electric motor (68) can be solidary with the electric motor (63) and are fixed together by means some brackets (69), and

the rotors (62), respectively (67) are counter-rotating, and

the air stream passing through the ducts (61) is increased due to the mounting in series of the rotors (62), respectively (67), and

a by-pass air stream is produced by the rotor (67) inside the duct (64), parallel with the air stream produced in the duct (61). 14. An aircraft as claimed in claim 4 or 8 wherein:

in case when the aircraft (1) or (80) has large and very large dimensions, the fuselage (2) or (81) can be filled with a gas easier than air, as it is helium, the gas can compensating partially or totally the weight of the aircraft (1) or (80), and

having extended dimensions the aircraft (1) or (80) can use on their superior surface some solar cells which can generate partially the necessary energy for propulsion.

15. A modular propulsion system as claimed in claim 1 wherein:

the modular propulsion system (7) or (85) can use a hybrid power unit (110), of redundant type, which supplies with electric energy the three groups of electric motors Ml-

1, Ml-2, Ml-n, respectively M2-1, M2-2, M2-n, respectively M3-1, M3-2, M3-n, each group corresponding to a multiple propeller, and

the hybrid power unit (110) furnishes the electric energy necessary for propulsion by means a fuel cell (111) which can work separately or together with a battery (112), the fuel cell (111) delivering the generated energy to a controller (113), and the controller (113) transmits the regulated electric energy to the battery (112) or directly to a distributor (114), and

the distributor (114) divides and distributes the necessary electric energy for each of the electric motors Ml-1, Ml-2, Ml-n, respectively M2-1, M2-2, M2-n, respectively M3-1, M3-2, M3-n, as is necessary and taking into account the commands of the pilot, and the hybrid power unit (110) is redundant and can work only with the energy delivered by the fuel cell (111), or only with the energy delivered by the battery (112), or using the both source of energy, and

due to the configuration of the hybrid power unit (110) the aircraft described before can operate safely even one or few electric motors are damaged, and

during operation, if the speed of the aircraft (1) or (80) is reduced in deceleration, a part of the electric motors Ml-1, Ml-2, Ml-n, respectively M2-1, M2-2, M2-n, respectively M3-1, M3-2, M3-n, or even all, can operate as a turbine-alternator and the produced/recovered energy is transmitted to recharge the battery (112).

16. A system as claimed in claim 15 wherein the fuel cell (111) is supplied from a tank (115) by means a reformer (116) which transform the fuel from the tank (115) in hydrogen and other residual substances, the residual substances being exhausted in atmosphere.

17. A system as claimed in claim 15 wherein the fuel cell (111) is supplied directly from a hydrogen tank.

received by the International Bureau on 27 July 2017 (27.07.2017)

1. A Vertical Take-Off and Landing ("VTOL") aircraft comprising a plurality of electrically powered ducted fans wherein an aircraft (1) uses a modular propulsion system (7) consisting of three multiple propeller having a linear shape.

2. An aircraft as claimed in claim 1 wherein two multiple propellers (8) are located in the front of the aircraft (1) and one multiple propeller (9) is located at the rear side of the aircraft (1).

3. An aircraft as claimed in claim 1 wherein an aircraft (80) uses a modular propulsion system (85) comprising one multiple propeller (85), located in the front of the aircraft (80), and two multiple propellers (87), located at the rear side of the aircraft (80).

4. An aircraft as claimed in claim 2 wherein:

the aircraft (1) has a fuselage (2) and some wings (3), extensible, located side by side from the fuselage (2), and

the fuselage (2) contains a cockpit (4), which has an aerodynamic shape and is extended with two members (5), distanced by an opening (6), and

each wing (3) contains a fixed part (16) and mobile part (17) which can be retracted inside of the fixed part (16), and

at the rear part of the aircraft (1), fixed on the members (5), there are two vertical stabilizers (18) which support a horizontal stabilizer (19), of the inversed type.

5. An aircraft as claimed in claim 4 wherein:

the two multiple propellers (8) are rotatable mounted on the cockpit (4) in the front of the wings (3), side by side from the fuselage (2), and

the multiple propeller (9) is located in the opening (6) and is rotatable mounted between the two members (5), and

each multiple propeller (8) or (9) has a main axis parallel with the middle plane of the aircraft (1), and

in the middle area of each multiple propeller (8) is fixed a shaft (12) which can be rotated solidary with the multiple propeller (8), and

in the middle area of the multiple propeller (9) are fixed two shaft (13) which can be rotated solidary with the multiple propeller (9), and

the shafts (12) or (13) can be acted by some actuators, and in the front of each multiple propeller (8) or (9) is fixed a wheel (14) by means a bracket (15), and

at the rear of the multiple propeller (8), aligned with the multiple propellers (8) are rotatable mounted two flaps (20) on the fuselage (2), and

at the rear of the multiple propeller (9), side by side, are rotatable mounted two flaps

(21) on the members (5), and

the flaps (20) and (21) are acted by actuators.

6. An aircraft as claimed in claim 5 wherein:

in operation, during take-off from a limited space, the mobile parts (17) of the wings (3) are retracted in the interior of the fixed parts (16) so that to minimize the footprint of the aircraft (1) and in the same time the multiple propellers (8) and (9) are in horizontal position and their air streams are vectored through down, and

when the aircraft (1) arrives at a certain befitting altitude the mobile parts (17) are extended to their maximum lengths being prepared to obtain the maximum aerodynamic lift in forward flight, and

in the transition from the vertical lift to the forward flight the multiple propellers (8) and (9) are acted in an inclined position which begins to push the aircraft (1) in forward flight, and in proportion as the horizontal speed of the aircraft (1) increases, the lift begins to be achieved exclusively by the wings (3), helped by the horizontal stabilizer (19), and

when aircraft (1) arrive near to the cruise speed the multiple propellers (8) and (9) arrive in vertical position and the air streams are horizontally oriented, and concomitantly the wings (3) and the horizontal stabilizer (19) sustain completely the aircraft (1).

7. An aircraft as claimed in claim 6 wherein:

in operation with low speed, near the ground, the control of the aircraft (1) is achieved by using the flaps (20), respectively (21) which can be oriented so that to cancel the influence of the side wind or can be used to make the rotation of the aircraft (1) around the vertical axis, and

in operation at high speed the aircraft control is made by changing the inclination angle of the multiple propellers (8) reported to the inclination angle of the multiple propeller (9), respectively by varying the rotation speed of electric motors which act the rotors, and

in the case of partial failure of the modular propulsion system (7), the aircraft (1) can glide with the help of the wings (3) as a fixed wing aircraft and can land on an airport runway using the wheels (14), and

the aircraft (1) can take-off and land from the water due to the natural floatability of its fuselage (2).

8. An aircraft as claimed in claim 3 wherein: the aircraft (80) comprises a fuselage (81), divided in two semi-bodies (82) which are united by a bridge (83), having in cross section an aerodynamic shape, and

on the aircraft (80) are fixed some wings (84), extensible, located side by side from the fuselage (81), and

each wing (94) contains a fixed part (92) and mobile part (93) which can be retracted inside of the fixed part (92), and

at the rear part of the aircraft (80), fixed on the semi-bodies (82), there are two vertical stabilizers (94) which support a horizontal stabilizer (95).

9. An aircraft as claimed in claim 8 wherein:

the multiple propeller (86) is rotatable mounted between the two semi-bodies (82) in the front of the aircraft (80), and other multiple propellers (87) are located at the rear side of the aircraft (80), rotatable mounted side by side from the fuselage (81), respectively behind the wings (84), and

in the middle area of the multiple propeller (86) are fixed two shafts (88) which can be rotated solidary with the multiple propeller (86), and

in the middle area of each multiple propeller (87) is fixed one shaft (89) which can be rotated solidary with the multiple propeller (87), and

the shafts (88) or (89) can be acted by some actuators, and

in the front of each multiple propeller (86) or (87) is fixed a wheel (90) by means a bracket (91), and

aligned with the multiple propellers (86) and side by side are rotatable mounted two flaps (97) on the fuselage (81), and

at the rear of the multiple propellers (87) are rotatable mounted two flaps (97) on the semi-bodies (82), and

the flaps (97) and (98) are acted by actuators. 10. An aircraft as claimed in claim 9 wherein:

in operation, during take-off from a limited space, the mobile parts (93) of the wings (84) are retracted in the interior of the fixed parts (92) so that to minimize the footprint of the aircraft (80) and in the same time the multiple propellers (86) and (87) are in horizontal position and their air streams are vectored through down, and

when the aircraft (80) arrives at a certain befitting altitude the mobile parts (93) are extended to their maximum lengths being prepared to obtain the maximum aerodynamic lift in forward flight, and

in the transition from the vertical lift to the forward flight the multiple propellers (86) and (87) are acted in an inclined position which begins to push the aircraft (80) in forward flight and in proportion as the horizontal speed of the aircraft (80) increases, the lift begins to be achieved exclusively by the wings (84), helped by the horizontal stabilizer (95), and

when aircraft (80) arrives near to the cruise speed, the multiple propellers (86) and (87) arrive in vertical position and the air streams are horizontally oriented, and

concomitantly the wings (84) and the horizontal stabilizer (95) sustain completely the aircraft (80).

11. An aircraft as claimed in claim 10 wherein:

in operation with low speed, near the ground, the control of the aircraft (80) is achieved by using the flaps (97), respectively (98) which can be oriented so that to cancel the influence of the side wind or can be used to make the rotation of the aircraft 1 around the vertical axis, and

in operation at high speed the aircraft control is made by changing the inclination angle of the multiple propeller (86) reported to the inclination angle of the multiple propellers (87), respectively by varying the rotation speed of electric motors which act the rotors, and in the case of partial failure of the modular propulsion system (85), the aircraft (80) can glide with the help of the wings (84) as a fixed wing aircraft and can land on an airport runway using the wheels (90), and

the aircraft (80) can take-off and land from the water due to the natural floatability of its fuselage (81).

12. A multiple propeller wherein:

a multiple propeller (50) contains a number of ducts (51) , in each duct (51) working two counter-rotating rotors (52), respectively (53), and

the rotor (52) is acted in rotation motion by an electric motor (54) and the rotor (53) is acted in rotation motion by an electric motor (55), and

the ducts (51) are tangent each other and take shape together a duct block (56), and the air stream passing through the ducts (51) is increased due to the mounting in series of the rotors (52), respectively (53).

13. A multiple propeller wherein:

a multiple propeller (60), contains a number of ducts (61), inside of each duct (61) working a rotor (62) located in the lower side of the duct (61), and the rotor (62) is acted in rotation motion by an electric motor (63), and

each duct (61) is fixed by means some brackets (65) inside of another duct (64), concentric with a duct (61), the walls of the duct (64) showing in a cross section an aerodynamic shape, and

the ducts (64) are tangent each other and take shape together a duct block (66), and inside of each duct (64) works a rotor (67) acted in rotation motion by an electric motor (68), and

the electric motor (68) can be solidary with the electric motor (63) and are fixed together by means some brackets (69), and

the rotors (62), respectively (67) are counter-rotating, and

the air stream passing through the ducts (61) is increased due to the mounting in series of the rotors (62), respectively (67), and

a by-pass air stream is produced by the rotor (67) inside the duct (64), parallel with the air stream produced in the duct (61). 14. An aircraft as claimed in claim 4 or 8 wherein:

in case when the aircraft (1) or (80) has large and very large dimensions, the fuselage (2) or (81) can be filled with a gas easier than air, as it is helium, the gas can compensating partially or totally the weight of the aircraft (1) or (80), and

having extended dimensions the aircraft (1) or (80) can use on their superior surface some solar cells which can generate partially the necessary energy for propulsion.