ES2690130B2 - DISTRIBUTED LOADING AIRCRAFT - Google Patents

Description

DESCRIPTION

DISTRIBUTED LOADING AIRCRAFT

Technical sector

The present invention is related to the aeronautical sector, proposing an aircraft with an improved design that allows homogenizing and distributing the supported aerodynamics along its supporting surfaces, allowing a simplification and a reduction of the aircraft's structure together with a improvement in stability, and that also allows to improve the behavior of the aircraft in the different actions in which the presence of side winds can pose problems on the proper functioning of the same.

State of the art

The aeronautics sector is dominated by a traditional aircraft concept that consists mainly of two slender lateral supporting surfaces that support the weight of a fuselage oriented to the transport of people or goods. Traditionally, said support surfaces project horizontally from the sides of the fuselage.

In such an aircraft concept, the effective bearing surface is limited with respect to the total plant of the aircraft, generating a relationship between the weight of the aircraft and that of the very high supporting surfaces. This relationship is known as alar load.

Traditional aircraft are also characterized in that the ratio between the maximum cargo they can carry (maximum payload) and their own structural load is very low, between 0.25 and 0.3. Nature shows that there are much more efficient systems such as ants, which get ratios of 30, or some birds that reach ratios of 3 or 4.

In any air vehicle two main and opposite forces are generated, the airfoil and the force of gravity. To balance the system and the moment associated with them, the aircraft have a built-in instep, usually located at the rear of the fuselage of the aircraft. Commonly, the rear instep It is formed by a vertical stabilizing surface that incorporates the rudder of the aircraft and two horizontal stabilizing surfaces each of which incorporates a rudder depth. This effort generates an aerodynamic load capable of compensating the moment generated by the force of gravity and the aerodynamic bearing force. The system allows stability to be achieved, but does not have a contribution to support; Moreover, the rear instep usually involves loads opposite to said lift, increasing the loads to be supported by the bearing surfaces.

It is also noteworthy the complexity involved in the manufacture of the instep. The union of the vertical and horizontal stabilizers with the fuselage implies a very complex and heavy structural design to be able to transmit the loads and torsions generated in flight. In this way, the instep is a component of limited functionality, which increases the weight of the aircraft considerably and whose cost is high. In addition, having a vertical component, completely exposed to lateral winds, favors the negative effect they have on the aircraft.

Within the aeronautical sector there is a high number of precedents of failures and accidents in the presence of lateral winds. The lateral winds affect the vertical control surfaces and especially the rear instep of the aircraft, modifying the ideal aerodynamics of flight and leading to risk situations.

The incidence of a lateral wind on a wide surface of the aircraft implies a force that tends to rotate the aircraft until it is positioned in the wind direction, equivalent to a weather vane. This trend, magnified by the presence of the large rear instep, implies the need to have controls in the vertical direction that compensate for that effect. However, compensation for this effect is difficult even by integrating said controls, generating risk situations especially in take-off and landing actions, actions in which the greatest number of accidents caused by this effect appear.

Documents US20110192663A1 and DE202004014384U1 show traditional concept aircraft with two slender lateral bearing surfaces that project horizontally from the sides of the fuselage. These aircraft lack rear instep and incorporate vertical control surfaces arranged at the tip of the supporting surfaces, which allows a structural simplification of the aircraft. Without However, since it is a traditional aircraft concept where the supporting surfaces project from the sides of the fuselage, the effective supporting surface is limited with respect to the total floor of the aircraft, generating a relationship (alar load) between the weight of aircraft and that of the very high supporting surfaces. Furthermore, these solutions do not solve the problem related to lateral winds, since the vertical control surfaces are directly exposed to said lateral winds because they are located at the tip of the supporting surfaces.

It is therefore necessary an aircraft that allows an optimal distribution of the lift loads generated while improving its behavior in the presence of side winds.

Document US20050236520A1 shows an aircraft according to the preamble of claim 1.

Object of the invention

The present invention aims at an aircraft with an improved design that has a distributed load bearing and that allows improving the behavior of the aircraft in the different actions in which the presence of side winds can pose problems on the proper functioning of the same .

The aircraft of the invention comprises:

• a main body;

• means of propulsion;

• a front support surface and a rear support surface that have an leading edge, an intrados part, an extrados part, and an exit edge; the front support surface is arranged in a front upper portion of the main body and the rear support surface is arranged in a rear upper portion of the main body;

• horizontal stabilizers located at the ends of the supporting surfaces; and

• at least two rear vertical stabilizers that are disposed on the intrados side of the rear support surface, one on each side of the main body.

With this configuration, the aircraft has an improved behavior against lateral winds to the direction of advance of the aircraft. Specifically, the arrangement of the rear vertical stabilizers in the intrados part of the rear support surface makes them less subject to lateral winds, which improves the behavior with respect to traditional aircraft that have a vertical projecting upward from the rear part of the main body, which is fully exposed to such winds, as well as to aircraft that have vertical control surfaces at the ends of the bearing surfaces.

In addition, the arrangement of the two bearing surfaces on an upper portion of the main body allows the two bearing loads generated by both bearing surfaces to be distributed in a controlled and substantially homogeneous manner, which allows the structural requirements of the bearing surfaces themselves to be reduced in relation to traditional aircraft with two slender side bearing surfaces that project horizontally from the side sides of the fuselage.

Additionally, the front support surface can have two front vertical stabilizers arranged in the intrados part of the front support surface, one on each side of the main body, so that vertical stabilizers are arranged in the intrados part of both support surfaces, improving the behavior of the aircraft.

The front and rear vertical stabilizers have a vertical section that is smaller than the vertical section of the main body of the aircraft, such that the vertical stabilizers do not protrude inferiorly from the lateral area projected by the main body. This further reduces the negative effect of side winds on vertical stabilizers.

Preferably, the vertical stabilizers are located symmetrically in the intrados part of the support surface, one on each side of the longitudinal axis of the main body, so that the distribution of loads on the support surface is optimized and maneuverability is improved.

Preferably the vertical stabilizers are displaced from the ends of the at least one bearing distance corresponding to one eighth of the wingspan of the bearing surface, this being the minimum distance at which said vertical stabilizers must be moved away from the end of the respective bearing surface so that the lateral winds do not affect them.

The front vertical stabilizers may be misaligned with respect to the rear vertical stabilizers. Thus, although preferably all vertical stabilizers are symmetrical with respect to the longitudinal axis of the main body, vertical stabilizers that are located on different bearing surfaces do not have to maintain the same distance with respect to the longitudinal axis of the main body. Thus, vertical stabilizers will be arranged in the most effective configuration that ensures more stable behavior of the aircraft.

The aircraft may incorporate one or more intermediate support surfaces between the front and rear support surfaces, said intermediate stabilizer intermediate support surfaces being able to be incorporated into its intrados part.

The vertical stabilizers are configured to rotate with respect to the supporting surfaces. On the other hand, horizontal stabilizers are also configured to rotate with respect to the supporting surfaces. Thus, a simpler structure for the maneuverability of the aircraft is obtained than in the case of aircraft with rear instep, where the yaw angle can be controlled by turning the vertical stabilizers and by turning the horizontal stabilizers You can control the pitch angle of the aircraft.

Preferably, the vertical and horizontal stabilizers are of the canard type and pivot entirely with respect to the supporting surface on which they are arranged. Canard type stabilizers have the advantage of being simple components in terms of manufacturing and robust.

Preferably, both vertical and horizontal stabilizers have an identical configuration, which allows both the complexity of the manufacturing process and the costs to be reduced.

In this way, the supporting surfaces are formed by fixed geometries, without The need to introduce complex mechanisms for their modification, since the stabilizers also act as control surfaces and are outside the geometry of the supporting surfaces. This configuration therefore allows the supporting surfaces and the vertical and horizontal stabilizers to be monocoque components, that is, each of them is shaped as a single component. The manufacture of monocoque components reduces or eliminates the need for joint components between parts, thus reducing the complexity of the process and the associated cost by reducing the number of necessary elements. Additionally, monocoque manufacturing facilitates the already complex certification process of an aircraft, as it simplifies the structure and reduces the amount of elements to be certified.

With all of this, an aircraft with an improved behavior is obtained in the face of the possible presence of lateral winds from the improved configuration of its supporting and stabilizing surfaces.

Description of the figures

Figure 1 shows a perspective view of an aircraft according to a first non-limiting example of the invention with vertical stabilizers on the rear bearing surface.

Figure 2 shows a front view of the aircraft of Figure 1.

Figure 3 shows a top view of the aircraft of Figure 1.

Figure 4 shows a side view of the aircraft of Figure 1.

Figure 5 shows a perspective view of an aircraft according to a second non-limiting example of the invention with vertical stabilizers on both bearing surfaces.

Figure 6 shows a front view of the aircraft of Figure 5.

Figure 7 shows a top view of the aircraft of Figure 5.

Figure 8 shows a side view of the aircraft of Figure 5.

Detailed description of the invention

A first non-limiting embodiment of the aircraft of the invention is shown in Figures 1 to 4. The aircraft comprises a main body (1) or fuselage intended to accommodate goods or passengers, propulsion means (2) of the aircraft, a front support surface (3), a rear support surface (4), horizontal stabilizers (5) , 6), and two rear vertical stabilizers (7).

The front (3) and rear (4) bearing surfaces have a wing-shaped configuration, each with a leading edge (3.1,4.1), a part of intrados (3.2, 4.2), a part of extrados ( 3.3, 4.3), and a trailing edge (3.4, 4.4).

The front support surface (3) is located in a front upper portion (1.1) of the main body (1), while the rear support surface (4) is located in a rear upper portion (1.2) of the main body (1), so that both support surfaces (3,4) are located above the main body (1), and the front support surface (3) is in front of the rear support surface (4) according to the direction of advance of the aircraft, with a horizontal separation distance between them.

The horizontal stabilizers (5,6) are located at the ends of the bearing surfaces (3,4), while the rear vertical stabilizers (7) are located in the intrados part (4.2) of the rear support surface (4) , one on each side of the main body (1).

As can be seen in Figure 3, the horizontal stabilizers (5,6) can rotate in full with respect to the supporting surfaces (3,4), so that by rotating the horizontal stabilizers (5,6) it is possible to turn control the angle of pitch of the aircraft, in addition to controlling the angle of warping.

On the other hand, as seen in Figure 4, the rear vertical stabilizers (7) can rotate in full with respect to the rear support surface (4), so that by turning the rear vertical stabilizers (7) You can control the yaw angle of the aircraft.

Thus, using two horizontal stabilizers (5,6) with the possibility of turning on one of the supporting surfaces (3,4) and two rear vertical stabilizers (7) on the rear supporting surface (4) the aircraft can be maneuvered by controlling the angles of nodding and yaw, in addition to warping, thus avoiding the need to use a complicated rear harness such as that of traditional aircraft. Additionally, a synchronized and symmetrical rotation of the vertical stabilizers (7) and a synchronized rotation of the horizontal stabilizers (5,6) allow the use of the stabilizers (5,6,7) as airbraking systems in landing actions.

The rear vertical stabilizers (7) are arranged symmetrically with respect to the longitudinal axis (a) of the main body (1), so that the two rear vertical stabilizers (7) are arranged in the intrados part (4.2) of the rear bearing surface (4), one on each side of the longitudinal axis (a) of the main body (1).

As can be seen in detail in Figure 2, the two rear vertical stabilizers (7) are displaced from the ends of the rear bearing surface (4) at least a distance corresponding to one eighth of the wingspan (E) of the bearing surface. rear (4). The size (E) of a supporting surface (3,4) means the distance between the ends of the supporting surface (3,4) without taking into account the horizontal stabilizers (5,6).

On the other hand, as can be seen in detail in Figure 4, the rear vertical stabilizers (7) have a vertical section that is smaller than the vertical section of the main body (1) on which they project perpendicularly, that is, a vertical stabilizer rear (7) does not protrude inferiorly from the lateral area projected by the main body (1), so that the vertical rear stabilization (7) of one side of the main body (1) is not affected by the lateral winds that impact from the other side of the main body (1).

A second non-limiting embodiment of the aircraft of the invention is shown in Figures 5 to 8, which has all the characteristics of the first embodiment and additionally has at least two front vertical stabilizers (8) which are arranged in the intrados part (3.2) of the front support surface (3), one on each side of the main body (1).

The front vertical stabilizers (8) are identical to the rear vertical stabilizers (7). Thus, the front vertical stabilizers (8) are arranged symmetrically with respect to the longitudinal axis (a) of the main body (1), can rotate in full with respect to the front bearing surface (4) and have a vertical section that It is smaller than the vertical section of the main body (1) on which they project perpendicularly.

As can be seen in figure 6, when front and rear vertical stabilizers (7.8) are used, the front vertical stabilizers (8) are misaligned with respect to the rear vertical stabilizers (7), leaving the front vertical stabilizers (8) closer to the main body (1) than the rear vertical stabilizers (7).

In the exemplary embodiments, aircraft with a pair of vertical stabilizers (7.8) are shown under each bearing surface (3.4), however, a greater number of vertical stabilizers could be provided under the bearing surfaces which would in turn allow get better maneuverability of the aircraft in flight. This would reduce the size of the vertical stabilizers, which would have a minor impact on the overall aerodynamic behavior of the aircraft and more precise control would be achieved when performing maneuvers.

In both embodiments, the aircraft generates a gravitational force approximately in the center of mass of the aircraft, while each supporting surface (3, 4) generates a respective aerodynamic supporting force that balances the system of forces generated in flight and the associated moment to them, so that the stability needs of the aircraft are practically covered only with the two supporting surfaces (3,4).

The rear support surface (4) is separated from the front support surface (3) a sufficient distance so that the rear support surface (4) is not excessively affected by the front support surface (3), and that the air reaches properly at its leading edge with the least possible turbulence.

The supporting surfaces (3, 4) are arranged one in front of the other approximately in the same horizontal plane, however they may be slightly offset from each other vertically, that is to say offset in a direction perpendicular to the longitudinal axis (a) of the main body (1) of the aircraft. The vertical offset is determined by the flight conditions, and mainly by the cruising speed at which the aircraft will navigate.

It is envisioned that the bearing surfaces (3, 4) have a substantially identical geometry, so that they generate similar aerodynamic bearing forces, while simplifying the manufacturing process. However, they could have slightly different geometries both at the rope level and at the level of relative thicknesses and curvatures of the aerodynamic profiles that make them up. Said differentiated geometries will allow the generation of aerodynamic loads on the different supporting surfaces to be according to the needs of the aircraft design; Thus, the aerodynamic lifting forces generated by the different supporting surfaces (3, 4) may be adjustable and adjustable according to the mass distribution of the aircraft itself and its load.

Given the use of horizontal stabilizers (5.6) and vertical stabilizers (7.8) located outside the supporting geometry of the supporting surfaces (3.4), and those stabilizers (5,6,7,8) being responsible for to offer maneuverability to the aircraft, the supporting surfaces (3,4) do not have movable parts or systems of modification of their geometry, which allows a more robust and less complex design at the time of certification, along with a more manufacturing simple and automated

Claims (8)

1 Distributed lift cargo aircraft, comprising: • a main body (1); • propulsion means (2); • a front support surface (3) and a rear support surface (4) having a leading edge (3.1, 4.1), a part of intrados (3.2, 4.2), a part of extrados (3.3, 4.3), and a trailing edge (3.4, 4.4); the front support surface (3) is arranged in a front upper portion (1.1) of the main body (1) and the rear support surface (4) is arranged in a rear upper portion (1.2) of the main body (1); and • horizontal stabilizers (5,6) located at the ends of the supporting surfaces (3,4); characterized in that it additionally comprises: • at least two rear vertical stabilizers (7) that are arranged in the intrados part (4.2) of the rear support surface (4), one on each side of the main body (1), and • at least two front vertical stabilizers (8) that are arranged in the intrados part (3.2) of the front support surface (3), one on each side of the main body (1), where the front and rear vertical stabilizers ( 7.8) have a vertical section that is smaller than the vertical section of the main body (1), such that the vertical stabilizers (7.8) do not protrude inferiorly from the lateral area projected by the main body (1). 2. - Distributed lift cargo aircraft according to the preceding claim, characterized in that the vertical stabilizers (7.8) are located symmetrically in the intrados part (3.2, 4.2) of the bearing surface (3,4) , one on each side of the longitudinal axis (a) of the main body (1). 3. - Distributed lift cargo aircraft, according to any one of the preceding claims, characterized in that the vertical stabilizers (7,8) are displaced from the ends of the supporting surface (3,4) at least a distance corresponding to a eighth part of the wingspan (E) of the supporting surface (3,4). 4. - Distributed lift cargo aircraft according to any one of the preceding claims, characterized in that the front vertical stabilizers (8) are misaligned with respect to the rear vertical stabilizers (7). 5. - Distributed lift cargo aircraft, according to any one of the preceding claims, characterized in that the vertical stabilizers (7,8) are configured to rotate with respect to the supporting surfaces (3,4). 6. - Distributed lift cargo aircraft, according to any one of the preceding claims, characterized in that the horizontal stabilizers (5,6) are configured to rotate with respect to the supporting surfaces (3,4). 7. - Distributed lift cargo aircraft, according to any one of the preceding claims, characterized in that the stabilizers (5, 6, 7, 8,) have an identical configuration. 8. - Distributed lift cargo aircraft according to any one of the preceding claims, characterized in that the supporting surfaces (2,3) and the vertical (7,8) and horizontal stabilizers (5,6) are monocoque components.