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1. WO2020191489 - MULTICOPTER HELICOPTER AND METHOD OF MANUFACTURE THEREOF

Note: Text based on automatic Optical Character Recognition processes. Please use the PDF version for legal matters

[ EN ]

TITLE OF THE INVENTION

MULTICOPTER HELICOPTER AND METHOD OF MANUFACTURE THEREOF

FIELD OF THE INVENTION

[0001] The present invention relates to a helicopter. Specifically, the present invention relates to a multicopter helicopter which combines the efficient design of a helicopter while using less expensive and simpler features of a multicopter.

BACKGROUND OF THE INVENTION

[0002] A multicopter is a rotorcraft with more than 2 rotors using fixed pitch propellers. Control of the aircraft is typically achieved by varying the speed of each propeller. In some variations, multicopters have variable pitch propellers, and lift and control is achieved by varying the pitch of the propellers, or varying the speed, or a combination of both with the goal of increasing thrust. In typical multicopters, rotors are of the same size, and produce the same thrust, and they are distributed symmetrically around the body of the aircraft. Typically, the center of gravity of the aircraft is located in the center of the aircraft, at an equal distance from each motor. Typically, the number of rotors are arranged in clockwise and counterclockwise pairs in order to cancel out torque. The smallest variants typically have three motors arranged in a triangle, with a clockwise and counterclockwise pair, and a third motor whose torque is cancelled out by pivoting the motor with a mechanism, usually a servo, to counter its torque and control the vehicle’s yaw. Typical multicopter propulsion systems are a direct drive from motor to propeller, though sometimes a reduction gearset is used on smaller models.

[0003] Recently, there have also been significant attempts to scale up multicopters for the purpose of carrying cargo or passengers. However, these attempts have been held back by short flight times and inefficient design. Furthermore, it is difficult to scale fixed propellers for multicopters past about 40 inches, or 50 inches, as the larger the propeller, the more power is required to accurately control its speed to control the aircraft. As a result, manned multicopters often have 8 rotors or more.

[0004] Looking at Unmanned Aerial Vehicles (UAVs), flight times are usually below 30 minutes, with only a handful claiming flight times of over 30 minutes; most with flight times 50 minutes or above are airplanes or expensive hybrids. Longer flight time drones tend to be more expensive, larger, and use large batteries (over 5kg in battery weight). Attempts to improve flight times have had limited success, and are usually described as a“flying battery” because the vast majority of their mass is the battery.

SUMMARY OF THE INVENTION

[0005] In accordance with the present invention, there is provided:

1. A multicopter helicopter comprising one main rotor and two or more secondary rotors operatively connected to a frame, wherein each of the secondary rotors are smaller in diameter than the main rotor, and wherein each secondary rotor is pivotably connected to the frame.

2. A method for manufacturing the multicopter helicopter defined above, comprising the steps of operatively connecting a main rotor to a multicopter helicopter frame, and pivotably connecting two or more secondary rotors to the frame.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] In the appended drawings:

FIGS. 1 to 4 show different perspectives of an embodiment of the present invention implemented with a“V” type frame. Specifically, Figure 1 shows a side view, Figure 2 shows a top view, Figure 3 shows a perspective view, and Figure 4 shows a back view of an embodiment of the present invention implemented with a“V” type frame.

FIGS. 5 to 6 show different perspectives of an embodiment of the present invention implemented with a“T” type frame. Specifically, Figure 5 shows a top view, and Figure 6 shows a perspective view of an embodiment of the present invention implemented with a“T” type frame.

FIG. 7 shows a close up of a pivotable secondary rotor of an embodiment of the multicopter helicopter of the present invention.

FIG. 8 shows a close up of two contra-rotating secondary rotors of an embodiment of the multicopter helicopter of the present invention.

FIG. 9 shows prior art to be used as a reference of a conventional three rotor multicopter helicopter.

FIG. 10 shows a perspective view of a“threecopter” multicopter helicopter, an embodiment of the present invention. FIG. 1 1 shows a close up of a secondary rotor on a“threecopter” multicopter helicopter, an embodiment of the present invention.

FIGS. 12-13 shows different perspectives of an additional embodiment of the multicopter helicopter of the present invention.

[0007] The description is given by way of example, and not limitation. Given the above disclosure, one skilled in the art could devise variations that are within the scope and spirit of the invention disclosed herein. Further, the various features of the embodiments disclosed can be used alone, or in varying combinations with each other, and are not intended to be limited to the specific combinations described herein. The scope of the claims is not to be limited by the illustrated embodiments.

DETAILED DESCRIPTION OF THE INVENTION

[0008] Turning now to the invention in more detail, there is provided a multicopter helicopter comprising one main rotor and two or more secondary rotors, as well as a method for manufacturing said multicopter.

Multicopter Helicopter

[0009] In a first aspect of the invention, a multicopter helicopter comprising one main rotor and two or more secondary rotors operatively connected to a frame is provided, wherein each of the secondary rotors are smaller in diameter than the main rotor, and wherein each secondary rotor is pivotably connected to the frame.

[0010] The multicopter helicopter of the present invention can work with either collective blade pitch control or fixed pitch propellers. The multicopter helicopter can take advantage of lower disc loading to generate more effective lift, similar to a helicopter. Disc loading relates to the weight of the aircraft (helicopter or multicopter) in relation to the rotor disc area, which is the area which the rotors sweep (i.e. the area of the circle created by the rotation of the rotor’s blades). Hover efficiency is closely related to this measure; generally speaking, the lower disc loading is, the more efficiently the aircraft hovers. There are, however, other considerations: larger rotors require more effort to speed up and slow down, making it more difficult to control a multicopter helicopter with fixed pitch propellers to maintain control. [0011] In preferred embodiments, the multicopter helicopter uses a fixed pitch propeller because of their simplicity, minimal maintenance and lesser costs. In embodiments, the multicopter helicopter uses collective pitch control, which allows for faster thrust change without requiring a change in RPM; collective pitch units, however, are more expensive, more complicated and require more maintenance than fixed pitch propellers.

[0012] Larger rotors are generally more difficult to control, and therefore, at some point in size, cause multicopters to become unstable, as the motors have more difficulty in speeding up and slowing down their speed to attempt to maintain control over the multicopter. Smaller rotors have less inertia, and therefore can be controlled more precisely. Therefore, smaller drones generally have faster and more precise reactions to inputs. The multicopter helicopter of the present invention takes advantage of both of these facts, avoiding the generally sloppy controls of a multicopter with excessively large rotors, by using smaller secondary rotors to control the multicopter helicopter.

[0013] In embodiments, the multicopter of the present invention uses one larger rotor for most of the lift, and in some embodiments almost all of the lift. The larger rotor is capable of this because if a rotor increases by a certain factor, the rotor disk area will generally increase by a square of that factor. For example, doubling the diameter of a rotor will quadruple the rotor disk area thereof, and therefore significantly lower disc loading, assuming the drone remains the same weight.

[0014] A large rotor generally provides smooth flight quality, but is unable to control the aircraft. This invention adds smaller pivotable secondary rotors, which act to control yaw, roll and pitch. Yaw generally refers to turning the rotorcraft left or right on the horizontal plane. Roll generally refers to pivoting the entire rotorcraft along its central axis to the left or to the right. Pitch generally refers to pointing the nose of the rotorcraft up or down. The weight distribution of the multicopter helicopter of the present invention is done so as to place most of the burden on the larger rotor, ensuring equally low loading on the secondary rotors. For example, a relatively large conventional quadcopter (four rotor multicopter helicopter), with four relatively equal-sized 15 inch rotors at 3kg in weight, would have 150% the disc loading of a multicopter with one large 30 inch rotor and two 15 inch secondary rotors at the same weight.

[0015] In embodiments, each secondary rotor pivots around an axis defined by a generally horizontal line passing through itself. For clarity, the term“generally horizontal line” means that the line defining the axis is generally within a horizontal plane of the secondary rotor. In preferred embodiments, such as that shown in Figures 1 -4, this line defining each axis passes through its corresponding secondary rotor 2A or 2B in a front to back direction of the multicopter helicopter.

[0016] In preferred embodiments, such as that shown in Figures 12 and 13, each secondary rotor 2A or 2B pivots around an axis defined by a generally horizontal line passing through itself 2A or 2B in a direction of the main rotor 1; in more preferred embodiments, said axis is parallel to the longitudinal axis of the corresponding arm of each secondary rotor 2A or 2B. In embodiments, from said line drawn between its corresponding secondary rotor and the main rotor, at least one of these axes can be offset on the horizontal plane by up to about 5 degrees, up to about 10 degrees, up to about 15 degrees, up to about 20 degrees, up to about 25 degrees, up to about 30 degrees, up to about 35 degrees, up to about 40 degrees, or up to about 45 degrees in either direction. For clarity, the angles defining said offset refer to the angle created on the horizontal plane between the axis around which a specific secondary rotor pivots and the line passing through the secondary rotor in question in the direction of the main rotor. For example, an offset of 30

degrees means that the axis and the line drawn between the secondary rotor and the main rotor create an angle of 30 degrees, while an offset of 0 degrees means that the axis is the line drawn between the secondary rotor and the main rotor.

[0017] The pivoting of the secondary rotors allows the secondary rotors to counter the main rotor’s torque by pivoting and to control the multicopter helicopter’s yaw. In embodiments, the secondary rotors can be positioned vertically (on a plane relatively perpendicular to that of the main rotor 1 , as shown for example in Figures 10 and 11 ) or horizontally (on a plane relatively parallel to that of the main rotor 1 , as shown for example in Figures 1 -4, 5-7, and 12-13).

[0018] In embodiments, the multicopter helicopter has two secondary rotors (such as those shown in Figures 1 -4, 5-7, 10-1 1 , and 12-13). In embodiments, the multicopter helicopter has three or more secondary rotors. In embodiments with two secondary rotors, the secondary rotors and the main rotors can be arranged in a way that, when viewed from above or below, they form a relatively isosceles triangle where the main rotor’s 1 position is at the apex of the triangle, such as in Figures 1 -4, 5-7, 10-1 1 , and 12-13.

[0019] In embodiments, the secondary rotors 2 22 are pivotably connected to the frame such that the blades thereof are located above the frame, as shown for example in Figures 1 -4, 5-7, and 12-13. In an alternative embodiment, the secondary rotors are pivotably connected to the frame such that the blades thereof are located below the frame.

[0020] In embodiments with two secondary rotors positioned horizontally, and as shown in Figure 2, the center of gravity CG of the multicopter helicopter can be located within the triangle formed by the placement of the rotors 1 2A 2B.

[0021] In embodiments with two secondary rotors, the frame can be shaped in a“V” form, as, for example, shown in Figs. 1-4, or a“T” form, as, for example, shown in Figs. 5-7. In embodiments with two secondary rotors positioned vertically, as for example in Figs. 10-11, the secondary rotors can both create thrust in the same direction, opposite to the torque of the main rotor.

[0022] In preferred embodiments with two secondary rotors positioned vertically, the center of gravity of the aircraft can be located directly under or above the main rotor. In other embodiments with two secondary rotors positioned vertically, the center of gravity can be offset to the front or the back by at most about 5%, at most about 10%, at most about 15%, at most about 20%, at most about 30%, at most about 40%, or at most about 50%.

[0023] In certain embodiments, when pivoting the secondary rotors to counter the main rotor torque, the lateral thrust of the secondary rotors can push the multicopter helicopter laterally. When this occurs, the main rotor can be canted, for example to the left or the right, in order to cancel out this lateral movement.

[0024] In embodiments, for example embodiments with one main rotor and two secondary rotors positioned vertically, the position of the secondary rotors to counter the main rotor’s torque results in the multicopter drifting laterally in the opposite direction. In embodiments, the main rotor is canted at an angle greater than 0 degrees in order to counter the drift caused by the vertical positioning of the secondary rotors.

[0025] Each secondary rotor can pivot around its axis up to any angle that will not adversely affect the capabilities of the multicopter helicopter. In embodiments, the secondary rotors can pivot around said axis up to about 10 degrees, up to about 20 degrees, up to about 30 degrees, up to about 40 degrees, up to about 50 degrees, up to about 60 degrees, up to about 70 degrees, up to about 80 degrees, up to about 90 degrees, up to about 100 degrees, up to

about 110 degrees, up to about 120 degrees, up to about 130 degrees, up to about 140 degrees, up to about 150 degrees, up to about 160 degrees, up to about 170 degrees, or up to about 180 degrees in either direction around said axis. In embodiments, the secondary rotors can pivot entirely around said axis in either direction.

[0026] In embodiments, the center of gravity of the multicopter helicopter is positioned in such a way as to distribute the multicopter helicopter’s weight across all rotors such that they all have about the same disc loading; the weight placed on each of the rotors can be in proportion to the area of the disc drawn by its respective propeller blades as it turns. In embodiments, the main rotor may have a disc loading of at least about 5%, at least about 10%, at least about 15%, at least about 20%, at least about 25%, at least about 30%, at least about 35%, at least about 40%, at least about 45%, or at least about 50% higher than the secondary rotors. In embodiments, the secondary rotors may each have a disc loading of at most about 5%, at most about 10%, at most about 15%, at most about 20%, at most about 25%, at most about 30%, at most about 35%, at most about 40%, at most about 45%, or at most about 50% higher than the main rotor. As explained above, disc loading relates to the weight the rotors are lifting in comparison to the area the rotors cover in one full rotation.

[0027] Figure 9 shows a conventional tricopter in order to compare the configuration of existing models and this invention. In this figure, we identify three identical propulsion units and rotors 32/31 placed in the general shape of an isosceles triangle. Each of these rotors produce about 33 and one third percent of the thrust required to fly. The center of gravity is located between the two front rotors 32. The front rotors 32 produce about 66 and two thirds of total thrust, and therefore the center of gravity is biased towards the front two rotors 32. The center of gravity 33 is biased about 33 and one third percent towards the back rotor 31 and biased about 66 and two thirds percent towards the front rotors 32. Between the center of gravity 33 and the front two rotors 32 the distance is about half the distance between the center of gravity 33 and the back of the tricopter.

[0028] In the multicopter helicopter of the present invention, the secondary rotors are smaller in diameter than the main rotor. In embodiments, the secondary rotors are about 50% the size of the main rotor in diameter. In embodiments, each of the secondary rotors have a diameter that is from about 10% to about 75% the diameter of the main rotor. In embodiments, each secondary rotor has a diameter that is at most about 75%, at most about 70%, at most about 65%, at most about 60%, at most about 55%, at most about 50%, at most about 45%, at most about 40%, at most about 35%, or at most about 30% the diameter of the main rotor, and/or at least about 10%, at least about 15%, at least about 20%, or at least about 25% the diameter of the main rotor. It is to be understood that any reference to the diameter of a rotor in the present application refers to the diameter of the circle created by spinning the blade of the rotor.

[0029] As mentioned, an advantage of embodiments of the multicopter helicopters of the present invention is that stability and tight control can be maintained even when larger rotors are used, for example with larger multicopter helicopters. In addition, by having a single large main rotor, lift is more efficiently produced, which can result in longer flight times.

[0030] The size of the main rotor, and accordingly the size of the smaller secondary rotors, will depend on the overall size, shape, and weight of the multicopter helicopters being designed. In general, larger and heavier multicopter helicopters require larger rotors. The size of multicopter helicopters is generally described as the distance between the furthest two rotors; for example, a 600mm multicopter helicopter will have its furthest two rotors 600mm apart. In embodiments the multicopter helicopter can be as small as 100mm. As the size of the multicopter helicopter increases, generally, so does its weight, although not necessarily proportionally. In preferred embodiments, the multicopter helicopter is about 600 mm in size.

[0031] In embodiments, the multicopter helicopter is at least about 200mm in size, at least about 300mm, at least about 400mm, at least about 500mm, at least about 600mm, at least about 700mm, at least about 800mm, at least about 900mm, at least about 1 m, or at least about 2m. In embodiments, the multicopter helicopter of the present invention can be about the size of a conventional helicopter in size.

[0032] In embodiments, the main rotor is from about 0.1 meter to about 22 meters, or more, in diameter. In embodiments, the main rotor is at least about 100mm, at least about 200mm, at least about 400mm, at least about 0.5 metres, or at least about 1 metre, and/or at most about 2 meters, at most about 3 meters, at most about 4 meters, at most about 5 meters, at most about 6 meters, at most about 7 meters, at most about 8 meters, at most about 9 meters, at most about 10 meters, at most about 15 meters, or at most about 20 meters. In embodiments, the main rotor can be the size of the propellers on a conventional helicopter.

[0033] In embodiments, the multicopter helicopter of the present invention is at least about 0.1 kg. In preferred embodiments, the multicopter helicopter is about 2.5 kg. In embodiments, the multicopter helicopter is at least about 0.5 kg, at least about 1 kg, at least about 2 kg, at least about 2.5 kg, at least about 5 kg, at least about 10 kg, at least about 25 kg, at least about 50 kg, at least about 100 kg, or at least about 200 kg. In embodiments, the multicopter helicopter of the present invention can be about the weight of a conventional helicopter. In general, the amount of weight that the rotors can carry will depend on their size; accordingly, heavier multicopter helicopters typically use larger rotors. However, in embodiments, one advantage of the multicopter helictoper of the present invention is that, when the weight of the multicopter helicopter is increased, the size and shape of the multicopter helicopter, including the size and arrangement of the rotors, do not have to be modified as much when compared to conventional multicopters.

[0034] The main rotor and the secondary rotor can be made of a variety of materials that are commonly used in multicopter rotors. In embodiments, each rotor can be made from, but not limited to, wood, plastics, carbon fiber, composites, metals and alloys, preferably carbon fiber.

[0035] In embodiments, the frame provides a structure to which to attach the main rotor and the secondary rotors. The skilled person would also understand that the frame of the multicopter helicopter of the present invention can be a variety of shapes, as long as it does not adversely affect the function of the multicopter helicopter.

[0036] In embodiments, the frame comprises a main body, and arms extending from the main body upon which to connect the rotors. In embodiments, each secondary rotor is attached to a separate arm of the frame.

[0037] The frame can be made using any combination of materials, including, but not limited to, wood, plastics, carbon fiber, metals and alloys, preferably carbon fiber. The main body of the frame should hold most of the electronics and/or batteries required to operate the multicopter. In embodiments, the main rotor and its power unit is directly attached to the main body. In embodiments, the main rotor is operatively attached to the main body via a motor mount of sorts.

[0038] In embodiments of this invention, the multicopter helicopter frame comprises 2 arms, making it more compact. In embodiments, the frame of the multicopter helicopter of the present invention is smaller in size, and lighter in weight, than conventional multicopter helicopter frames. Using a compact frame means the weight to size ratio decreases advantageously with increases in size, so as to reach a point where the weight to size ratio is smaller on bigger multicopter helicopters allowing for lower disc loading (by also increasing the size of the main rotor and/or secondary rotors), and longer flight times.

[0039] As mentioned, the secondary rotors are pivotably connected to the frame. In embodiments, the secondary rotors can pivot in a way that allows them to counter the torque of the main rotor; to control the multicopter helicopter’s yaw; and/or to contribute thrust for lift. In preferred embodiments, the secondary rotors can pivot in a way that allows them to both counter the torque of the main rotor as well as control the multicopters’ yaw. In embodiments, the yaw of the multicopter helicopter can be controlled by a combination of pivoting the secondary rotors and thrust corrections (for example, speeding up or slowing down) to compensate for the change in the angle of the thrust. In embodiments, by being able to counter the torque of the main rotor, contribute thrust for lift, and/or control the multicopter helicopter’s yaw by pivoting the secondary rotors, less power is used, and longer flight times can be achieved.

[0040] The secondary rotors can be pivotably connected to the frame in a variety of manners, such as by using a pivoting mechanism. In embodiments, the secondary rotors are pivotably connected to the frame using a pivot, which is mechanically linked to a servo. In embodiments, the secondary rotors can be directly attached to an end of a servo bracket, while the other end of the servo is attached directly to the frame.

[0041] In embodiments, the secondary rotors can be attached to the frame by means of a pivot, and a linking arm to an actuator, hydraulic, or pneumatic actuator which allows for pushing and pulling, pivoting the secondary rotor around its axis. In embodiments, the secondary rotors are pivotably connected to the frame using a pivot, which is mechanically linked to a motor through a reduction gear set. In embodiments, a closed loop system, whereby the angle of the secondary rotors is reported to the control unit in real time, is used. In embodiments, an open loop control unit is used, whereby the control unit inputs actions, and adjusts based on reactions of the multicopter helicopter without being informed of the actual angle of the secondary rotors.

[0042] Figure 7 shows an example of how the pivoting mechanism for the secondary rotors could function. The figure shows the“T” style frame with an arm 55 attached to a pivoting mechanism 7 and the pivot point 8 which is attached to a propulsion unit mount 9. The propulsion unit mount 9 is able to pivot back and forth in a way to control the multicopter helicopters yaw. A propulsion unit 3 is attached to the propulsion unit mount 9 to which the rotor 2 is attached through a direct drive.

[0043] In embodiments, the main rotor should carry at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 80%, at least about 90%, or a total of about 100% of the multicopter helicopter’s weight and, in consequence, the main rotor should be able to produce at least about 40%, at least about 45%, at least about 50%, at least about 55%, at least about 60%, at least about 65%, at least about 70%, at least about 80%, at least about 90%, or up to about 100% of the total thrust.

[0044] The lift, roll and pitch of the craft can be controlled by increasing or decreasing total thrust from each of the rotors. The specific mechanisms to do this (for example, fixed or collective pitch control) and the available power

sources (for example, electric, internal combustion, or other hybrid variations) would be understood by the person of skill in the art.

[0045] In general, to increase altitude, all rotors need to produce more thrust in a manner which is proportional to the weight that they are responsible in lifting; to decrease altitude, the rotors reduce thrust proportionally to the weight that they are responsible in lifting.

[0046] As mentioned, in embodiments, the yaw is controlled by a combination of pivoting the secondary rotors around their respective axis (defined above) and thrust corrections to compensate for the change in the angle of the thrust.

[0047] In preferred embodiments, the main rotor further comprises collective blade pitch control.

[0048] In preferred embodiments, the secondary rotors further comprise collective blade pitch control.

[0049] In preferred embodiments, all of the rotors further comprise collective blade pitch control.

[0050] In embodiments, the multicopter helicopter is an unmanned vehicle.

[0051] In embodiments, the multicopter helicopter is a manned vehicle.

[0052] In embodiments, for example as shown in Figure 8, the secondary rotors 82 822 on the arms 855 are each made up of two power sources 83 833, and two contra-rotating rotors 82 822, with an appropriate pivoting mechanism 87, pivot point 88, and propulsion unit mount 89. In such embodiments, if a failure occurs in one of the secondary rotors, the multicopter would still be able to land safely. In embodiments, the secondary rotors 82 822 and/or the main rotor are each made of contra-rotating rotors.

[0053] In preferred embodiments, the main rotor and secondary rotors are on the same horizontal plane (as shown in the embodiment of Fig. 1 ).

[0054] In embodiments, the secondary rotors are on a different horizontal plane than the horizontal plane of the main rotor.

[0055] In embodiments, the secondary rotors are outside of the circumference created by spinning the blade of the main rotor, either on the same plane, or on a different horizontal plane than the main rotor.

[0056] In embodiments, the secondary rotors are above or below the main rotor’s horizontal plane, and partially or completely within the circumference created by spinning the blade of the main rotor in order to keep the multicopter helicopter’s overall footprint to a minimum.

[0057] In embodiments with two secondary rotors, the secondary rotors can both spin in the same direction (counterclockwise or clockwise), opposite from the main rotor, in order to partially counter the torque generated by the main rotor. The remaining torque differential can be countered by pivoting the secondary rotors. For clarity, the“spin” of the rotors refers to the spinning of the rotor blades, as opposed to the pivoting of the rotors around the axis defined above.

[0058] In embodiments with two secondary rotors, the secondary rotors can spin in opposite directions (clockwise/counterclockwise pair), in order to counter each other’s torque. The full torque produced by the main rotor, in such embodiments, is countered by pivoting the secondary rotors.

[0059] In embodiments, the secondary rotors are distributed symmetrically around the main rotor.

[0060] In embodiments, the secondary rotors are distributed asymmetrically around the main rotor.

[0061] In embodiments, the center of gravity of the multicopter helicopter is positioned centrally, above or below the main rotor.

[0062] In embodiments, the center of gravity is offset from the center of the main rotor.

[0063] In embodiments, the secondary rotors are not all of the same size.

[0064] In embodiments, the main rotor and/or each secondary rotor is a ducted propeller or a ducted fan, which is made up of a propeller and a shroud or duct surrounding it to enhance its thrust efficiency.

[0065] A person skilled in the art would understand that, instead of secondary rotors, other propulsion equipment can be used to produce thrust, such as, but not limited to, turbofans and jets. In such embodiments, the propulsion equipment is still pivotably connected to the frame as defined above. In embodiments, each embodiment utilizing secondary rotors defined above can be used with other propulsion equipment. If something other than a secondary rotor is chosen, it should be chosen so that it has similar flight control capabilities as a secondary rotor as defined above. For example, if a turbofan is chosen, it should be chosen to correspond to the flight control capabilities of a secondary rotor of the size defined above.

Tricopter Helicopter

[0066] In preferred embodiments (for example, as shown in Figures 1 to 7, as well as Figure 12 and 13), the multicopter has three rotors 1 2, of which one is a main rotor 1 and the other two secondary rotors 2 are positioned at an about equal distance from the main rotor, said secondary rotors being positioned horizontally (on a plane relatively parallel to that of the main rotor 1, which is generally horizontal when not canted). This embodiment is known as the“Tricopter Helicopter”.

[0067] FIGS. 1 to 7 are a general representation of preferred embodiments of the Tricopter Helicopter of the present invention comprising“V” type frame arms 5 (Figs. 1 -4) or“T” type frame arms 55 (Fig. 5-7) that are connected to the main body 6, to which the main propulsion unit (motor) 4 is directly attached, and to which a fixed pitch main propeller is directly attached; in combination, the propeller and the motor 4 represent the main rotor 1. The overall frame of the multicopter of Figs. 1 -7 is made up of a combination of the body 6 and the arms 5/55. The secondary propulsion units (motors) 3 is attached to the arms 5/55 of the frame via a mechanism which allows the propulsion units to tilt in either direction and the propulsion unit (motor) is attached via a pivoting mechanism 7 around a pivot point 8. The secondary propulsion units’ (motors) fixed pitch propellers 2 are attached directly onto the propulsion unit 3 in combination representing a secondary rotor.

[0068] FIG. 7 is a close up of a secondary rotor of Figs. 5-6, which is a combination of a propulsion unit (motor) 3 and a fixed pitch propeller 2. It shows pivot points 8 and the mechanism 7 which pivots the rotor 2B.

[0069] Figs 12 and 13 also show an embodiment of the Tricopter helicopter; more detail regarding said embodiment is given below in the section describing illustrative embodiments.

[0070] In embodiments of the Tricopter Helicopter, the two secondary rotors are in a more or less horizontal position, as shown for example in Figures 1 to 7. A person skilled in the art would know that the propellers, while in a more or less horizontal position, should still be pivoted in a direction opposite to the torque produced by the main rotor 1 in order to counter the rotation force of the main rotor torque. The rotors 1 2A 2B are preferably arranged in a way that, when viewed from above or below, they form a relatively isosceles triangle where the main rotor’s 1 position is at the apex of the triangle. As mentioned, the secondary rotors 2 can be connected to a mechanism 7 which allows them to pivot in a way that allows them to both counter the torque of the main rotor 1 as well as control the multicopters’ yaw.

[0071] In the embodiments shown in Figures 1 to 7, the secondary rotors 2 are attached to a motor mount 9 which is attached to a pivot at a pivot point 8, which is operatively attached to the arms 5 55 of the frame of the tricopter helicopter and a servo 7 or other pivoting mechanism in a way which allows them to pivot around an axis more or less parallel with the central axis of the body of the tricopter helicopter (or as defined above, an axis defined by a generally horizontal line passing through the secondary rotor 2A or 2B in a front to back direction of the multicopter helicopter).

[0072] In embodiments, such as that shown in Figures 12 and 13, each secondary rotor 2A or 2B pivots around an axis defined by a generally horizontal line passing through itself 2A or 2B in a direction of the main rotor 1; in preferred embodiments, said axis is parallel to the longitudinal axis of the corresponding arm of each secondary rotor 2A or 2B.

[0073] In embodiments, the center of gravity CG of the tricopter should be located within the triangle formed by the placement of the rotors 1 2A 2B. The center of gravity CG should be located so as to distribute disc loading as equally as possible across all three rotors 1 2A 2B; as the main rotor 1 is larger, it would result in a center of gravity CG that is biased towards the main rotor 1 (see Fig. 2 for an example). For clarity, a center of gravity that is biased towards the main rotor indicates how close it is to the main rotor compared to the secondary rotors. For example, if the center of gravity is biased 100% towards the main rotor (and 0% towards the secondary rotors), it means the center of gravity is located at the main rotor.

[0074] In embodiments, the center of gravity can be biased at least about 33%, at least about 50%, at least about 66%, at least about 75%, or at least about 80% towards the main rotor, and/or at most about 100%, at most about 95%, at most about 90%, or at most about 85% towards the main rotor.

[0075] In embodiments, the center of gravity can be biased about 33%, about 50%, about 66%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100% towards the main rotor, preferably about 80%.

[0076] In preferred embodiments, the center of gravity can be biased between 80 and 95% towards the main rotor 1. Placing the center of gravity in this range increases the efficiency of the craft while maintaining enough weight on the secondary rotors 2 to control the multicopter.

[0077] In embodiments of the tricopter, the tilting of the secondary rotors to counter the main rotor’s 1 torque results in the multicopter drifting laterally in the opposite direction. In embodiments, the main rotor is canted at an angle greater than 0 degrees in order to counter the drift caused by the tilt of the secondary rotors 2.

[0078] In preferred embodiments, the frame is shaped in a“V” form, as, for example, shown in Figs. 1-4, with arms 5 extending from the main rotor 1 and/or main body 6 to each of the secondary rotors 2. This is one of any number of possible frame formats and should not be considered a limiting factor of how this invention should be designed. In other preferred embodiments, the frame is shaped in a“T” form, as, for example, shown in Figs. 5-6, with the body 6 extending from the main rotor 1 towards the center of both secondary rotors 2, and two arms 55 extending from the end of the body towards each of the secondary rotors 2 forming a“T” type frame. This is one of any number of possible frame formats and should not be considered a limiting factor of how this invention should be designed.

[0079] In embodiments, the secondary rotors 2 both turn in the same direction (counterclockwise or clockwise), opposite from the main rotor 1, in order to partially counter the torque generated by the main rotor 1. The remaining torque differential is countered by pivoting the secondary rotors 2

[0080] For example, in the embodiments shown in Figures 1-4, each secondary rotor 2 is pivotably connected to its respective arm such that the blade of each secondary rotor is located above the arms 5, and both secondary rotors 2 spin in the same direction. In order to roll the multicopter left, one would increase the thrust on one of the secondary rotors 2B and decrease the thrust on secondary rotor 2A. To roll right, one would do the opposite. The main rotor 1, in this example, spins counterclockwise. The torque of the main rotor 1 will cause the multicopter to spin clockwise, while the torque of both secondary rotors 2 will partially counter the torque effect of the main rotor 1. In order to stabilize the multicopter, the pivoting mechanism 7 needs to pivot both secondary rotors to the left, causing a counterclockwise yaw movement countering the clockwise torque created by the main rotor 1. In order to yaw the aircraft to the left, the tilting mechanism 7 would tilt the rotors 2 to the right; in order to yaw to the right, the tilting mechanism 7 would tilt the rotors 2 to the left.

[0081] In embodiments, the secondary rotors 2 turn in opposite directions (clockwise/counterclockwise pair), in order to counter each other’s torque. The full torque produced by the main rotor 1, in such embodiments, is countered by pivoting the secondary rotors 2

[0082] In preferred embodiment of this tricopter helicopter, such as those in Figures 1 -4, the tricopter helicopter can tilt left by producing more thrust in the secondary rotor on the right 2B and less in the secondary rotor on the left 2A, or tilt right by increasing thrust in secondary rotor on the left 2A and less in secondary rotor on the right 2B. It can pitch down by increasing the thrust in both secondary rotors 2, or pitch up by decreasing thrust in secondary rotors 2. In this preferred embodiment, the tricopter multicopter can yaw to the right by pivoting secondary rotors 2 to the left in order to aim their thrust to the right; it can also yaw to the left, by pivoting secondary rotors 2 to the right in order to aim their thrust to the left.

Multicopter Helicopter with three or more secondary rotors

[0083] In embodiments, the multicopter helicopter could have one main rotor, and three or more secondary rotors radially positioned around the main rotor and body and center of gravity. In embodiments, said secondary rotors are positioned horizontally (on a plane relatively parallel to that of the main rotor, which is generally horizontal when not canted). As mentioned, the secondary rotors are attached to a mechanism which allows them to pivot from side to side in a manner which allows them to counter the main rotor’s torque and to control the multicopters’ yaw. The secondary rotors also control tilt and roll of the multicopter by speeding up or slowing down their speed.

[0084] As mentioned, in embodiments, the lift, roll and pitch of the craft is controlled by increasing or decreasing total thrust from each of rotors. In embodiments of the multicopter helicopter with three or more secondary rotors, each axis around which each secondary rotor pivots is defined by a generally horizontal line passing through the secondary rotor in question in a direction of the main rotor.

Threecooter

[0085] In embodiments, the multicopter helicopter has one main rotor 1, and two secondary rotors 22 22A 22B positioned vertically, as for example shown in Figures 10 and 11 (on a plane relatively perpendicular to that of the main

rotor 1, which is generally horizontal when not canted). This embodiment is known as the“Threecopter”. In such an embodiment, the frame can comprise“V” type frame arms or“T” type frame arms 555 (as shown for example in Figures 10 and 11 ).

[0086] In this embodiment, the multicopter has three rotors 1 22A 22B, of which one is a main rotor 1 and the other two secondary rotors 22 are positioned at an about equal distance from the main rotor 1. The rotors should be arranged in a way that, when viewed from above or below, they form a relatively isosceles triangle where the main rotor’s 1 position is at the apex of the triangle.

[0087] As mentioned previously, the secondary rotors 22 are connected to a mechanism which allows them to pivot or swivel in a way that allows them to both counter the torque of the main rotor as well as control the multicopters’ yaw, pitch and roll. In embodiments, the secondary rotors both create thrust in the same direction, opposite to the torque of the main rotor.

[0088] In preferred embodiments, the center of gravity CG of the aircraft should be located directly under or above the main rotor. In other embodiments, the center of gravity CG can be offset to the front or the back by at most about 5%, at most about 10%, at most about 15%, at most about 20%, at most about 30%, at most about 40%, or at most about 50%.

[0089] In the Threecopter, with one main rotor 1 , and two secondary rotors 22, the vertical position of the secondary rotors 22 to counter the main rotor’s 1 torque can result in the multicopter drifting laterally in the opposite direction. In embodiments, the main rotor 1 is canted at an angle greater than 0 degrees in order to counter the drift caused by the vertical positioning of the secondary rotors 22.

[0090] In embodiments of the“Threecopter” configuration, the thrust of both the secondary rotors 22 is pointed in the same direction in a way to counter the main rotor’s 1 torque. The secondary rotors 22 can control pitch by pivoting in the same direction (both clockwise or both counterclockwise), and they can control roll by pivoting in opposite directions (one clockwise and one counterclockwise), and they can adjust the thrust they produce to maintain control of the yaw.

[0091] In preferred threecopter embodiments, such as that shown in Figures 10 and 1 1 , the threecopter can be pitched up by rotating the thrust of both secondary rotors 22 upwards and pushing the tail of the threecopter helicopter down relative to the position of the main rotor 1. This embodiment of the threecopter multicopter can be pitched down by rotating the thrust of both secondary rotors 22 downwards and pushing the tail of the threecopter helicopter up relative to the position of the main rotor 1.

[0092] In embodiments, such as that depicted in Figures 10 and 1 1 , the threecopter multicopter can roll to the left by rotating the thrust of the right secondary rotor 22B downwards, and the thrust of the left secondary rotor 22A upwards. To roll to the right, the opposite action would be performed. To yaw to the left or to the right, the combined thrust created by the secondary rotors 22 would be increased or decreased depending on the direction the thrust is produced (to the left or the right) and the spinning direction of the main rotor 1 (clockwise or counterclockwise).

[0093] For clarity, the secondary rotors pivot their thrust“upwards” by pivoting in the direction that will result in the thrust of the rotor being pointed in a more upwards direction, while the secondary rotors pivot their thrust“downwards” by pivoting in the direction that will result in the thrust being pointed in a more downwards direction. For example, for the embodiment shown in Figures 10 and 1 1 , if both secondary rotors 22 are producing thrust in a left to right direction, rotating the thrust of the secondary rotors 22 upward means, when viewed from the back, both secondary rotors 22 are rotated counterclockwise; conversely, rotating the thrust of the secondary rotors 22 downward means, when viewed from the back, both secondary rotors are rotated clockwise.

[0094] In embodiments, the main rotor 1 is primarily responsible for creating the thrust required for lift; it plays only a minimal role in controlling yaw, roll and pitch. In embodiments, the secondary rotors 22 are responsible for the majority control of the yaw, roll and pitch; they contribute minimally to thrust for lift.

[0095] In embodiments, the Threecopter’s main rotor 1 is responsible for creating up to 100% of the lift, while the secondary rotors 22 would be up to 100% responsible for controlling pitch, roll and yaw. As a result, in a stable hover, i.e., not moving forward, backwards, left, right, up or down, the secondary rotors 22 are both tilted at about 90 degrees from the horizon, and they are both producing thrust in the same direction in order to counter the main rotor’s torque.

[0096] As mentioned, in the embodiment shown in Figure 10, the secondary rotors are in a generally vertical position, with the secondary rotors facing away from a central axis of the frame.

Method of manufacturing the multicopter helicopter

[0097] In a second aspect of the invention, a method of manufacturing the above multicopter helicopter is provided.

[0098] The method for manufacturing the multicopter helicopter of the present invention comprises the steps of: operatively connecting a main rotor to a multicopter helicopter frame, and pivotably connecting two or more secondary rotors to the frame.

[0099] The main rotor can be operatively connected to the frame using any method known in the art.

[00100] The secondary rotors can be pivotably connected to the frame using any method known in the art, so long as they are pivotably connected to the frame in the manner defined in the previous section. For example, the secondary rotors can be pivotably connected to the frame by means of a pivot, and a linking arm to an actuator, hydraulic, or pneumatic actuator which allows for pushing and pulling, pivoting the secondary rotor around its axis. In embodiments, the secondary rotors are pivotably connected to the frame using a pivot, which is mechanically linked to a motor through a reduction gear set.

[00101] The main rotor, the two or more secondary rotors, the multicopter helicopter, and the frame are as defined above.

Advantages of the Invention

[00102] In embodiments, the multicopter helicopter of the present invention can present one or more of the following advantages:

[00103] In embodiments, the multicopter helicopter of the present invention combines the efficiency of a helicopter, with the simplicity of construction and maintenance of a multicopter.

[00104] Leveraging lower disc loading: In embodiments of this invention, disc loading is lowered, meaning less power is required to lift the same amount of weight. Embodiments of the present invention have the advantage of flying longer or carrying less weight in batteries (if present) than traditional multicopters.

[00105] In general, fixed pitch propellers do not scale efficiently; they require an exponentially larger amount of power through the inertia created by the propellers to control their speed with the precision required to control the multicopter. In embodiments of the present invention, by placing most of the requirements for lift on one large rotor, fewer control inputs are required on said rotor; as a result, the inertia of the propeller has a smaller importance on the control of the multicopter. Instead, control inputs are mostly driven to the secondary rotors, whose smaller size means less inertia is encountered by the propulsion unit in order to speed up and slow down the rotors for control; the multicopter is therefore more responsive to control inputs, and easier to control.

[00106] In embodiments of the present invention having only three rotors (one main rotor and two secondary rotors) the frame of the multicopter can be smaller, lighter, easier to build, and less expensive than traditional multicopters since it only has two arms to support the secondary rotors, as per for example the“V” frame embodiment (for example, as shown in Figs. 1 -4 and 12-13). Since the secondary rotors carry less weight, the arms also do not need to be as heavy and strong as those on traditional multicopters since, typically speaking, they might only be responsible for carrying, for example, at most about 5%, at most about 10%, at most about 15%, or at most about 20%, of the total weight of the aircraft each. In conventional tricopters, each arm is responsible for over 33 and a third % of the weight of the aircraft, and in conventional quadcopters (four rotor symmetrical multicopters), each arm is responsible for about 25% of the total weight of the aircraft.

[00107] In conventional larger multicopters, 3 or more large and expensive rotors are sometimes required. In larger embodiments of the present invention, only one large and expensive main rotor is required. The secondary rotors of the present invention, as they are smaller than the main rotor, can use smaller motors and smaller propellers which are more widely available on the market and are relatively inexpensive. Overall, the cost of the rotors (propulsion units and propellers) of the multicopter helicopters of embodiments of the present invention can be significantly less expensive than those of traditional multicopter helicopter rotors.

[00108] In preferred embodiments using fixed pitch propellers, the multicopter helicopter of the present invention does not require helicopter swash plate units or collective pitch controls. Swash plate units and collective pitch control units can be expensive, complicated, comprise many critical components, and require significantly more maintenance than fixed pitch propellers.

Potential Applications

[00109] The above described multicopter helicopters can be used inter alia in the following markets: land surveying for construction or mining, situational awareness for civil security applications (fire fighting and police situations, for example), transportation of goods, or photography. As mentioned, the above described multicopter helicopter can also be the size of a conventional helicopter in order to carry cargo or people, among other uses.

Definitions

[00110] The use of the terms "a" and "an" and "the" and similar referents in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context.

[00111] The terms "comprising", "having", "including", and "containing" are to be construed as open-ended terms (i.e., meaning "including, but not limited to") unless otherwise noted.

[00112] Recitation of ranges of values herein are merely intended to serve as a shorthand method of referring individually to each separate value falling within the range, unless otherwise indicated herein, and each separate value is incorporated into the specification as if it were individually recited herein. All subsets of values within the ranges are also incorporated into the specification as if they were individually recited herein.

[00113] All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context.

[00114] The use of any and all examples, or exemplary language (e.g., "such as") provided herein, is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention unless otherwise claimed.

[00115] No language in the specification should be construed as indicating any non-claimed element as essential to the practice of the invention.

[00116] Herein, the term "about" has its ordinary meaning. In embodiments, it may mean plus or minus 10% or plus or minus 5% of the numerical value qualified.

[00117] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs.

[00118] Other objects, advantages and features of the present invention will become more apparent upon reading of the following non-restrictive description of specific embodiments thereof, given by way of example only with reference to the accompanying drawings.

[00119] The scope of the claims should not be limited by the preferred embodiments set forth in the examples, but should be given the broadest interpretation consistent with the description as a whole.

DESCRIPTION OF ILLUSTRATIVE EMBODIMENT

[0120] FIG 12-13 show an illustrative embodiment of a preferred embodiment of the tricoptermulticopterthatwasconstructed and tested. In this embodiment, the tricopter helicopter is made of a carbon fiber sheet cut down to hold all the electronics required for flight in the main body 6. The main rotor 1 is directly attached to the main propulsion unit 4, which is a brushless DC electric motor and is attached to a motor mount 10, attached to the main body 6. The frame is completed by attaching two arms 5 in a“V” shape. The front landing gear 12 is attached to the main body 6 part of the frame. The rear landing gears 11 are attached to the ends of each of the arms 5 making up the frame.

[0121] The rear rotor units are made up of a servo 7 which is attached directly to the frame. A motor bracket 9 is operatively attached to the servo, allowing it to pivot around a pivot point 8 to the left and to the right of the axis made up of each of the arms 5 of the frame. The propulsion unit is a brushless DC motor 3 which is directly attached to the secondary rotors 2.

[0122] The illustrative embodiment shown in FIG 12-13 carries a 10.5 amp 6S lithium ion battery. The main rotor 1 is about 24 inches in diameter and the secondary rotors 2 are each about 13 inches in diameter. The total weight of the multicopter is 2.4kg and flight tests showed a total battery consumption of only 10 to 1 1 amps, resulting in an estimated flight time of over 50 minutes. In this illustrative embodiment, the arms are about 550mm long, and are positioned 35 degrees from center. Each secondary rotor 2A or 2B pivots around an axis defined by a generally horizontal line passing through itself 2A or 2B in a direction of the main rotor 1 , such that each secondary rotor 2A or 2B pivots around an axis that is parallel to the longitudinal axis of its corresponding arm of the frame.

REFERENCES

[0123] The present description refers to a number of documents, the content of which is herein incorporated by reference in their entirety. These documents include, but are not limited to, the following:

• US9616994B2

• WO2018139661 A1

• US10124888B2