DE202014004877U1 - Composite Quadrotor - Google Patents

Abstract

The invention relates to a composite quadrotor with an electrically driven VTOL lifting system and a separate drive for forward flight as well as aerodynamic surfaces, characterized in that two support bars (2, 2 ') aligned parallel to the longitudinal axis (1) have a dual function for aerodynamic Connect surfaces (4, 5) to one another and lift motors (3, 3 ') can be mounted on the support bars (2).

Description

State of the art

Quadrootors have established themselves as VTOL (Vertical Take Off and Landing) devices because of their special advantages in certain applications (eg camera flights, toys). The term "quadrotor" (or quadcopter, quad) generally refers to aircraft with horizontal rotor / propeller plane and multiple electric drives. The term "rotor", which is naturalized in quads, is misleading, since it concerns propellers without cyclical and collective blade adjustment (see helicopter rotor). In the further description, however, the term rotor should be retained here for reasons of clarity, even if it is a propeller.

The main advantages of the quads are simple speed control of the electric motors (no rotor blade adjustment required), ideal flight mechanical hub geometry and low production costs. Due to the stable hovering property, automated flight profiles (eg VTOL phase, coming home function) can be realized with cost-effective control. Another quad advantage is the almost noiseless and emission-free hovering. A more detailed description of the quad action is among others DE 10 2005 014 949 refer to.

In the Quad construction, the concept has prevailed with four rotors in a star-shaped arrangement with respect to easily manageable flight mechanics with low mechanical complexity.

The decisive disadvantages of the quadrotor, however, are low range and airspeed, which is due to the limited battery capacity and the lack of forward flight propulsion. In addition, the unfavorable weight-to-power ratio of the battery reduces the payload. Thus, various missions can not be detected by the quads. Here are other aircraft in the advantage, especially surface or compound aircraft with VTOL drives: tilt rotors, tilting propeller, Kippflügler, winds in the wing (eg. DE 299 16 203 ), Compound helicopter / gyrocopter. But these types are more or less fraught with difficulties such. B. high mechanical complexity (blade adjustment, shaft system, actuating cylinder, etc.), complex control, high maintenance, high jet surface load (low specific thrust), rotor down wind acts on wings and reduces lifting capacity. To avoid these disadvantages, the company Arcturus / USA ( Flight Magazine, Apr. 29, 2014, p. 16; see. Drawing Fig. 1d ) presented a drone, which represents a combination of surface aircraft and quad. In this configuration, only an existing airframe is supplemented by a quadrotor in this configuration, without the combination of airframe / quadrotor being optimally designed in accordance with the technical possibilities, so that obvious disadvantages arise here (see description 1d ).

task

After the above analysis of VTOL devices, it is an object of the invention to improve the combination airframe / quadrotor in terms of aerodynamics and weight over the prior art, so as to expand the flight range in terms of speed, radius of use and flight duration. Areas of application are diverse drone missions but also - depending on future battery development - light aircraft construction in question.

description

Following the term "compound helicopter" (helicopter with separate forward flight drive and possibly wings) is proposed here for the combination of an airframe with a quadrotor, plus separate drive for the forward flight, the term "compound quadrotor".

The composite quadrotor according to the invention is characterized according to claim 1 by two slender supporting beams, which connect the aerodynamic surfaces (wings, tail units) in a dual function and at the same time serve as a basis for the rotor drives. This concept ensures that the surface, weight and resistance can be minimized. The two supporting beams replace the conventional fuselage as a tail boom, while a profile drop mounted on the wing or duck tail is provided for receiving the payload. Furthermore, the support bars also ensure the formation of a duck / tandem configuration; also a Nurflügel Quad is possible.

The compound quad typically has electrically driven lift rotors, supplemented by a separate drive for forward flight. For a longer flight duration, this is most likely to be compared to the electric drive an internal combustion engine in question. This is preferably at the rear of the o. G. Profile drop between the support beams mountable so as to ensure in the case of a drone application the front mounted sensors an undisturbed field of view.

Due to the system, the shear center of the rotors must coincide with the center of gravity of the airframe in the composite quadrotor. For this purpose, the length of the supporting bars to adapt or it is proposed according to the invention that the Lifting units are designed differently before and behind the center of gravity with respect to rotor diameter and / or drive power. Thus, a displacement of the shear center is possible and the Tragholmlänge can be minimized (see, in contrast to 1d ).

In addition, it should be noted that the installation of the lifting units on the support bars allow rotors with large diameters, resulting in low jet area loading (high specific thrust). In addition, no aerodynamic surfaces are acted upon by the rotor tailwind, whereby the full lifting capacity is maintained.

drawings

The invention is illustrated with reference to drawings and described in more detail. The figures show:

1 the state of the art with examples 1a - 1d ,

2 the compound quad rotor according to the invention in a drone design

3 configuration options

4 a flying wing configuration

5 an embodiment of the invention as a light aircraft

In 1 In the prior art, a selection of VTOL devices is sketched.

Fig. 1a

The drawing shows the typical structure of a quad rotor with four electrically driven lifting units at the ends of the cantilever arms and the central housing for control and batteries. With this design, flight duration and range are limited, so that only short operations at close range are possible.

Fig. 1b

The sketch shows the toy model "Raptor Dogfight Quadcopter F2". The airframe surrounding a quadrotor is merely a dummy for simulating a VTOL aircraft. Ultimately, all maneuvers are dependent on the built-Quadrotor, as a propulsion propeller is missing. After all, the small propellers integrated in the cell only provide a small amount of specific thrust due to high jet area loading.

Fig. 1c

The system drawing shows a two-page view of the "Panther" drone of IAI / Israel ( Flight Magazine, Feb. 11, 2014, p. 15 ). The VTOL drone has three electrically driven tilting propellers. Only a portion of the battery capacity is used for the range flight, which is favorable compared to other VTOL devices. The disadvantage is that a part of the propeller down-wind acts on the wing and thus reduces the lifting efficiency. In addition, the tilt angle of the propeller pods in the transition phase must be synchronized with the forward speed, which requires a more complex control and mechanics.

Fig. 1d

Shown is a sketch of the o. G. Drone of the company Arcturus / USA, whereby a quadrotor system is integrated in an existing airframe. It can be seen that the shear center is in the center of gravity and therefore the front rotor carrier must be designed to be longer than the rear carrier. In the structural integration of the voluminous hull remains as a tail boom, which causes weight and surface and deteriorates the aerodynamics. In addition, the hull construction allows the installation of a pressure screw in the rear rather not (focus problem), which gives the sensors in the front fuselage because of the front drive only a limited field of view.

Fig. 2

The drawing shows the compound quad rotor according to the invention in a drone design. The two to the longitudinal axis ( 1 ) parallel supporting beams ( 2 ) the aerodynamic surfaces connect wings ( 4 ) and tail units ( 5 ), whereby in each case the Tragholmkonus ( 2 ' ) is slim and low-resistance educable. On the carrying spars ( 2 ) are the electric lifting motors ( 3 ) whose rotors are the rotor / propeller circular surfaces ( 6 ) form. It can be seen that the rotor's downwash affects the aerodynamic surfaces ( 4 . 5 ) is not affected. Depending on the design of the jet surface load, the rotor diameter can be increased, without the length, but not the concept of supporting beams would have to be changed.

The thrust result of the lifting motors ( 3 ) is related to the location of the center of gravity ( 7 ) of the airframe identical. This is about 25% of the mean chord depth ( 8th ). This ensures a stable flight behavior in the VTOL phase as well as in normal flight, which here by slight sweep of the wing ( 4 ) is achieved.

To accommodate the required flight systems (control, regulation, partly Power supply) serves the central and low resistance arranged hull gondola ( 10 ). For forward flight is a separate from the rotor lifting system drive ( 9 ), which preferably as Druckschraubenantrieb at the rear of the fuselage nacelle ( 10 ) is installed. This provides a good field of view for the sensors at the front. Thus, with the composite quadrotor concept of the invention, the main criteria of aerodynamic drag, weight and sensor efficiency can be improved.

Fig. 3

As an extension of the applications of the invention, a duck / tandem aircraft is shown. The two supporting beams ( 2 ) connect wings ( 4 ) and tail unit / tandem wing ( 5 ). The spars ( 2 ) serve as the basis for the lifting motors ( 3 ), whereby the rotor circuit surfaces ( 6 ) are placed between the aerodynamic surfaces so that the rotor tailwind does not interfere. Due to the configuration, the shear center ( 7 ) or the center of gravity between the aerodynamic surfaces ( 4 . 5 ), which ensures flight stability in all flight phases. The advantage of this aircraft configuration is the more compact construction compared to the normal aircraft. In addition, the rotors are located between the aerodynamic surfaces ( 4 . 5 ), which offers more safety against injury in ground operation.

Fig. 4

Shown is a flying wing ( 4 ) integrated with two carrying beams ( 2 ) and lifting motors ( 3 . 3 ' ). For adjusting the stroke resultants to the center of gravity position ( 7 ) are the front hoist motors ( 3 ' ) with a lower power and rotor circuit area ( 6 ' ) Mistake. With this device according to the invention it is possible, in addition to influencing the rotor geometry, the length of the supporting beams ( 2 ) to minimize.

Fig. 5

The drawing shows in plan view a version of the composite quad rotor in a version as a two-seat light aircraft. The drive ( 9 ) for forward flight can be located next to the position at the stern of the fuselage nacelle ( 10 ) also be mounted elsewhere, here z. B. on the wing ( 4 ). The cabin for the pilots is located in the hull gondola ( 10 ). Due to the existing quadrotor technology, the VTOL phase can be completely automated, which relieves the pilot. Also, the usual landing flap can be omitted. Regarding the reliability of electric lifting motors, there are various possibilities: connecting shaft system, autorotation (propeller blade adjustment required), horizontal landing.

LIST OF REFERENCE NUMBERS

1

Aircraft longitudinal axis (= symmetry axis)

2

spar

2 '

Carrying beam cone

3, 3 '

Elektrohubmotor

4

wing

5

tailplane

5 '

Duck / Tandem wing

6, 6 '

Rotor / propeller-circular surface

7

Center of gravity = rotor thrust center

8th

Mean chord depth

9

Drive forward flight

10

hull gondola

QUOTES INCLUDE IN THE DESCRIPTION

This list of the documents listed by the applicant has been generated automatically and is included solely for the better information of the reader. The list is not part of the German patent or utility model application. The DPMA assumes no liability for any errors or omissions.

Cited patent literature

• DE 102005014949 [0002]
• DE 29916203 [0004]

Cited non-patent literature

• Flight Magazine, Apr. 29, 2014, p. 16; see. Drawing Fig. 1d [0004]
• Flight Magazine, 11 Feb. 2014, p. 15 [0020]

Claims (7)

The invention relates to a composite quad rotor with an electrically driven VTOL lifting system and a separate drive for forward flight and aerodynamic surfaces, characterized in that two parallel to the longitudinal axis ( 1 ) oriented supporting beams ( 2 . 2 ' ) in a dual function the aerodynamic surfaces ( 4 . 5 ) and on the girders ( 2 ) Lifting motors ( 3 . 3 ' ) are mountable. Composite quad rotor according to claim 1, characterized in that flight system components and payloads in one of the aerodynamic surfaces ( 4 respectively. 5 ) attached hull gondola ( 10 ) are housed. Composite quadrotor according to claim 1 and 2, characterized in that the position of the thrust resulting ( 7 ) of the rotors in the direction of the longitudinal axis ( 1 ) is changeable by the rotor circuit surfaces ( 6 . 6 ' ) and / or power of the lifting motors ( 3 . 3 ' ) in front of and behind the center of gravity ( 7 ) are differently formable. Composite Quadrotor according to claim 1 to 3, characterized in that the supporting beams ( 2 . 2 ' ) the connection between a front duck / tandem wing ( 5 ' ) and rear main wing ( 4 ), the lifting motors ( 3 ) in between on the Holmen ( 2 . 2 ' ) are placeable. Composite quadrotor according to claim 1 to 4, characterized in that the drive ( 9 ) is installed for forward flight at the stern of the hull gondola. Composite quadrotor according to claim 1 and 2, characterized in that the hull gondola ( 10 ) can be formed as a passenger cabin. Composite quadrotor according to one of claims 2 to 6, characterized in that in a flying wing configuration two supporting beams ( 2 ) symmetrical to the longitudinal axis ( 1 ) are arranged.

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