ES1301888U - airfoil for aircraft - Google Patents

Abstract

Aerodynamic surface (1) for aircraft, comprising a ballast located inside said aerodynamic surface (1), characterized in that the ballast comprises a bar (2). (Machine-translation by Google Translate, not legally binding)

Description

DESCRIPTION

airfoil for aircraft

field of invention

The present invention relates to an airfoil for aircraft, which allows a ballast to be placed in a position closer to the tip of the airfoil to ensure its vibration within undulation or flutter or flutter margins.

Background of the invention

When designing an airfoil for an aircraft, for example a horizontal tailplane, a vertical tailplane, a wing, etc., it is necessary to ensure that it vibrates within a flutter or flutter range.

This undulation, or flutter or flutter, is a vibration that occurs when aerodynamic forces exerted on an object cause natural periodic motion. This movement is fed back in positive conditions, that is, if there is more vibration, movement and downforce, the more downforce, the more movement and vibration.

It is precisely this feedback that makes this phenomenon dangerous, since these vibrations can appear on the aerodynamic surfaces, causing premature fatigue of the material or fracture of the surface where the undulation or fluttering or fluttering is taking place. from the margins.

Usually, to guarantee vibration within this undulation range, a ballast is added near the end of the aerodynamic surface that modifies the rigidity and vibration characteristics of the structure so that this undulation or fluttering does not appear for the operating speeds of the aircraft. aircraft.

This ballast, for example, can be one or several blocks of high-density steel that are placed as close as possible to the end of the aerodynamic surface within its internal structure, mainly affecting the flexural rigidity of the structure, although may affect torsional stiffness when placed at the front and rear of the drawer of torsion

The structural attachment of the ballast to the airfoil near the airfoil tip is limited due to the width of the airfoil tip itself. This is because the ballast must be placed on the inside of the airfoil, since it cannot be placed on the outside, because it would compromise the aerodynamic properties of the surface.

Therefore, in practice, the center of gravity of this ballast is shifted away from the nose and inboard of the airfoil, limiting the beneficial effect of the ballast and therefore requiring the ballast to have a greater weight, which also has drawbacks.

Description of the invention

Therefore, an objective of the present invention is to provide an aerodynamic surface for airplanes that allows a ballast to be placed inside it in a position as close as possible to the tip of the same.

With the aerodynamic surface for airplanes of the invention, the aforementioned drawbacks are solved, presenting other advantages that will be described below.

The airfoil for aircraft according to the present invention is disclosed in claim 1, and the dependent claims include additional features that are optional.

In particular, the aerodynamic surface for aircraft comprises a ballast located inside said aerodynamic surface, in which the ballast comprises a bar, that is to say, a narrow and longitudinal shape, being able to be a cylindrical, square or other section bar whose length is much greater than the cross section.

Thanks to the fact that the ballast is a bar, it allows it to be placed closer to the inner edge of the airfoil than when using metal blocks, without being necessary to increase its weight.

Advantageously, the bar is connected to the rest of the airfoil by means of a plurality of tie rods, which preferably extend perpendicular to the bar.

Furthermore, the tie rods are preferably grouped in pairs, the tie rods of each pair forming an acute angle.

With this type of joint, the bar can be adequately fixed to the rest of the airfoil, being able to withstand the dynamic loads that occur on the airfoil.

Furthermore, according to a preferred embodiment, the bar is cylindrical and made of tungsten, which is a suitable material to be used as ballast, with more than twice the density of steel, and the bar is advantageously located substantially parallel to the outer edge of the airfoil.

Brief description of the drawings

For a better understanding of what has been exposed, some drawings are attached in which, schematically and only as a non-limiting example, a practical case of realization is represented.

Figure 1 is a perspective view of an example of an airfoil for aircraft in accordance with the present invention.

Description of a preferred embodiment

In figure 1 the aerodynamic surface (1) for airplanes is shown, in particular a wing, although it could be any other aerodynamic surface, such as, for example, a horizontal tailplane or a vertical tailplane.

As previously indicated, in order to ensure that the vibration of the aerodynamic surface (1) is within undulation or flutter or flutter margins, a ballast is placed inside the surface (1), which must be located as close as possible possible from the edge (4) of the airfoil (1).

It should be noted that figure 1 shows the interior of the aerodynamic surface (1) for to be able to see its interior, that is, the position of the ballast inside said aerodynamic surface (1).

According to the present invention, the ballast comprises a bar (2), ie an elongated body, which is positioned next to and substantially parallel to the inner edge (4) of the airfoil (1).

Furthermore, according to the depicted embodiment, the bar (2) is cylindrical, although it could have any suitable cross section.

Preferably, the bar (2) is made of tungsten, which has been shown to have the appropriate characteristics to be used as ballast, such as its density and cost.

The connection of the bar (2) to the rest of the aerodynamic surface (1) is preferably carried out by means of tie rods (3), which extend perpendicular to the longitudinal axis of the bar (2).

According to the embodiment shown, the tie rods (3) are grouped in pairs, the tie rods (3) of each pair forming an acute angle.

These tie rods (3) are positioned and dimensioned to be able to withstand the dynamic loads that occur on the aerodynamic surface (1) during its use in an airplane.

In this way, thanks to the fact that the bar (2) is long and narrow, it can be placed closer to the inner edge of the aerodynamic surface (1) than conventional ballasts, being able to weigh less and achieve the same effect of limiting vibration. of the airfoil (1).

Claims (7)

1. Aerodynamic surface (1) for aircraft, comprising a ballast located inside said aerodynamic surface (1), characterized in that the ballast comprises a bar (2). An airfoil (1) for aircraft according to claim 1, wherein the bar (2) is connected to the rest of the airfoil (1) by means of a plurality of tie rods (3). Airfoil (1) for aircraft according to claim 2, in which the tie rods (3) extend perpendicular to the bar (2). Airfoil (1) for aircraft according to claim 2 or 3, in which the tie rods (3) are grouped in pairs, the tie rods (3) of each pair forming an acute angle. Airfoil (1) for aircraft according to any one of the preceding claims, wherein the bar (2) is located parallel to the outer edge (4) of the airfoil (1). Aerodynamic surface (1) for aircraft according to any one of the preceding claims, in which the bar (2) is made of tungsten. Aerodynamic surface (1) for aircraft according to any one of the preceding claims, in which the bar (2) is cylindrical.