FR2468503A1 - WING FOR HIGH-SPEED AIRCRAFT DESIGNED TO REDUCE INDUCED RESISTANCE - Google Patents

Abstract

Wing for high speed airplanes designed to reduce induced drag. Two wings 10, 11 placed one behind the other in the direction of flight are arranged in a cross with respect to each other and are mutually connected by a torsionally rigid tube 12 so that the induced resistance of the wing is further reduced for a total lift remaining constant

Description

Wing for high-speed aircraft designed so

to decrease the induced resistance.

  The present invention relates to a wing for high-speed aircraft, preferably for high-performance aircraft. With the various embodiments of the wings according to the state of the art, for a predetermined lift, the induced resistance of an aircraft design is reduced either by increasing the wingspan or by deploying

  the vortex trail in the area of the wingtips.

  By way of example, mention may be made of biplane systems, systems with end discs and wings with forked ends. Most of these proposed solutions have the disadvantage that the decrease in strength is accompanied by an increase in the structural weight of the wing and that only the wings with forked ends cause some

  decreased resistance for the same wing weight.

  The configuration according to the German patent application 55 718 seeks to solve these difficulties by the fact

  than two wings swung backwards, arranged one

  above each other and mutually constituting a closed frame have the shape of a rhombus with an upper wing forming a negative dihedral and a lower wing forming a positive dihedron, the two wings merging into one another in their zone end. This embodiment certainly gives rise to a higher value of portaxce and a decrease in weight compared to other forms of wings belonging to the state of the art, but these values are

still to improve.

  The present invention therefore aims to further reduce the induced resistance of the wing while

  maintaining the same total lift and the same size.

  This result is achieved according to the invention in that two wings placed one behind the other in the direction of flight are arranged crosswise relative to each other * and are mutually connected by a rigid tube to flexion. In this design according to the invention, the front partial wing, seen in the direction of flight, forms a positive dihedral, while the rear partial wing forms a negative dihedral. According to another advantageous characteristic of the invention, the flexural rigid tube completely covers the two partial wings and protrudes by its

  ends beyond the outer edges of the partial wings.

  This tube also has an aerodynamic shape.

  The invention will be better understood by means of the description

  An embodiment, taken as an example, but not limited to, and illustrated by the accompanying drawing, in which: Figure 1 schematically shows a partial front view of the configuration of the wing; Figure 2 schematically shows a plan view of the wing according to Figure 1;

  FIG. 3 is a diagram showing the distribution

  thickness and load due to bending moments

  wings according to the state of the art and according to the invention.

  As illustrated in FIGS. 1 and 2, two wings 10, 11 placed one behind the other in the direction of flight are arranged on the fuselage 13 of the aircraft so that the front wing forms a positive dihedron and the rear wing a dihedron

  negative. Both wings are soaring and interconnected

  lement by a tube 12 rigid flexion. Thanks to this design, it is possible for this so-called crossed wing to have, with respect to all the wing designs known hitherto, very distinct advantages, namely a considerable reduction in the bending stress of the wings, since each partial wing is an effective support for

  the other partial wing. Moreover, under the effect of

  and the separation of the marginal vortex, the resistance

  The induced lift is considerably reduced for the same total lift and span. As revealed by the first tests, this is a decrease

up to 24%.

  It has furthermore been found that the wing plane and the cross wing are of a substantially identical weight when for the same air-swept surface and for the same relative thickness of profile, the span of the crossed wing represents 0.955 times that of the classic wing. This relatively small reduction in the scale leads to an effective reduction of the

induced resistance of about 17%.

  It has furthermore been found that because of the substantially smaller cross sectional area of the two partial wings, the wave resistance regresses by about% and that the wing surface is aerodynamically better.

  exploited as illustrated in the diagram of Figure 3.

  The reason is the bilinear distribution of depths

  which is closer to the ellipse than the trapeze.

  It is worth mentioning here that the proposed design and arrangement of the wings allow for an order

  very effective lateral efforts.

  - In the proposed example, the torsionally rigid tube 12 is made so that it covers the two partial wings from one end to the other and projects from its ends beyond the outer edges of the wings, these projecting ends.

being performed aerodynamic.

2468503.

Claims (4)

  1. Wing for high-speed aircraft, preferably for high-performance aircraft, characterized in that two wings (10,11) placed one behind the other in the direction of flight are arranged in a cross, one for each to each other and are mutually connected by a tube (12) rigid flexion.   2. Wing according to claim 1, characterized in that the front partial wing (10), seen in the direction of flight, forms a positive dihedral, while the partial wing   rear (11) forms a negative dihedral.   Wing according to claims 1 and 2, characterized   in that the rigid flexural tube (12) covers   from side to side the two partial wings (10,11).   4. Wing according to any one of the claims   1 to 3, characterized in that the bending rigid tube (12) protrudes at both ends beyond the outer edges of the partial wings and presents an aerodynamic shape.