High glide wing parachute with leading edge slotted wing and method of operation thereof

Abstract

The application discloses a high-slip wing parachute with a front edge slotted wing and a working method thereof. The wing parachute canopy configuration is composed of a conventional wing parachute canopy and a front edge slotted wing. The slotted wing is located above a front edge cut of the canopy and is sewn with the upper wing surface fabric and the rib on both chord directions. When the wing parachute works, the slotted wing bulges and forms a gap between the slotted wing and the upper wing surface, so that the kinetic energy of the upper wing surface appendage airflow is increased, the airflow distribution of the upper wing surface is improved, the airflow separation of the wing parachute during high-attack-angle flight is effectively inhibited, the maximum lift-drag ratio of the wing parachute is increased, the stall attack angle is increased, the flight stability of the wing parachute system is increased, and the structural design of the high-slip wing parachute is of great significance.

Description

Technical Field

[0001] This invention relates to the field of parachute design, and more particularly to a high-altitude glider with leading-edge slats and its operating method. Technical Background

[0002] Paragliders are increasingly used in sports performances, airdrops, and space recovery due to their superior gliding performance. The lift-to-drag ratio of the paraglider canopy directly determines its gliding performance and affects the maximum gliding distance of the paraglider system. Compared with traditional airfoils, paragliders have a notch on the leading edge, which is used to maintain the rigidity of the air chamber during inflation. Therefore, compared with traditional airfoils, paragliders have a lower lift coefficient, a higher drag coefficient, and a significantly lower lift-to-drag ratio. Under high angle-of-attack flow conditions, paragliders are more prone to flow separation on the upper surface, which lowers the critical angle of attack, leading to paraglider stall and a sharp drop in lift coefficient and lift-to-drag ratio. Therefore, improving the flow field around the paraglider and reducing flow separation on the upper surface is of great importance to the safety of the paraglider.

[0003] Currently, there are not many methods to improve the lift-to-drag ratio of parachutes by changing their structural composition. Most research focuses on improving the structural parameters of the parachute itself, such as improving the position and height of the leading edge notch and using thin airfoils to increase the lift-to-drag ratio. However, most of these improvements reduce the parachute's inflation performance, thus having a limited effect on improving the parachute's gliding performance. Summary of the Invention

[0004] This invention aims to propose a high-gliding paraglider with leading-edge slats and its operating method. While ensuring smooth paragliding inflation, it effectively improves the paragliding performance. A slat design is added to the leading edge of the paraglider's notch. During operation, a gap is formed between the slats and the upper wing surface, allowing incoming airflow to pass through. The airflow is accelerated through this gap, increasing the kinetic energy of the airflow attached to the upper wing surface and improving the airflow distribution on the upper wing surface. This effectively suppresses airflow separation at high angles of attack, increases the lift coefficient and maximum lift-to-drag ratio, and improves the stall angle of attack, thus significantly enhancing the paragliding performance.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A high-flying glider with leading-edge slats is disclosed. The glider canopy configuration consists of a conventional glider canopy and leading-edge slats. The slats are located above the leading-edge cut of the canopy and are sewn to the upper wing fabric and ribs on both sides in the chord direction. Reinforcing bands are provided at the leading and trailing edges of the slats, but are not sewn to the wing surface. The leading-edge width of the slat fabric block is 120% to 140% of the spanwise length of the air cell, and the trailing-edge spanwise length is slightly smaller than the leading-edge width, which can be taken as 110% to 120% of the spanwise length of the air cell. The leading-edge slat tip is flush with the canopy cut, and the chordwise length of the slat is 8% to 15% of the glider chord length.

[0007] Preferably, the canopy and the leading edge seams are made of non-breathable or low-breathable fabric blocks.

[0008] Preferably, the leading edge slat is sewn to the upper wing fabric and ribs of the parachute along the chord by a rolled or flat stitch, and the leading and trailing edges of the slat are provided with reinforcing strips and are not sewn to the wing surface.

[0009] Preferably, when the parachute is folded, the slits are close to the upper wing surface; when the parachute is fully inflated, the slits bulge, forming an airflow channel between them and the upper wing surface. The height of the channel is determined by the spanwise length of the slits. The width of the leading edge of the slit fabric block is 120% to 140% of the spanwise length of the air chamber, and the spanwise length of the trailing edge is slightly smaller than that of the leading edge, which can be 110% to 120% of the spanwise length of the air chamber. The leading edge of the slit is flush with the cut of the parachute canopy, and the chord length of the slit is 8% to 15% of the parachute chord length.

[0010] This invention also discloses a method for operating a high-altitude paraglider with leading-edge slats. Based on the aforementioned high-altitude paraglider with leading-edge slats, when the paraglider takes in air, the canopy expands, the air chamber quickly fills, the leading-edge slats open upwards and form a bulge. Once the air chamber is full and generates sufficient lift, the paraglider begins to operate. A gap is formed between the leading-edge slats and the upper wing surface, allowing airflow to pass through. Airflow from the upper wing surface flows out through this gap, causing the leading-edge slats to bulge rapidly. This improves the airflow distribution on the upper wing surface of the paraglider, delays airflow separation during high angle-of-attack flight, and increases the paraglider's glide ratio.

[0011] Compared with the prior art, the beneficial effects of this invention are as follows: by setting slats on the upper wing surface to improve the airflow on the wing surface, increase the kinetic energy of the boundary layer flow, effectively suppress the airflow separation at high angles of attack of the airfoil, improve the aerodynamic performance of the paraglider at high angles of attack, enable the paraglider to glide and control within a wider angle range of attack, increase the gliding capability and flight stability of the paraglider system, and have important significance for the structural design of high-gliding paragliders. Attached Figure Description

[0012] Figure 1 This is a three-dimensional schematic diagram of a high-glide parachute with leading-edge slats according to the present invention;

[0013] Figure 2 This is a schematic cross-sectional view of a high-glide parachute canopy with leading-edge slats according to the present invention;

[0014] Figure 3 This is a comparison diagram of the lift coefficients of a high-lift paraglider with leading-edge slats according to the present invention and a conventional paraglider;

[0015] Figure 4 This is a comparison diagram of the lift-to-drag ratio of a high-glide parachute with leading-edge slats according to the present invention and a conventional parachute;

[0016] Figure 5Comparison of two-dimensional pressure cloud maps of a wing parachute with leading edge slits and a conventional wing parachute at a 14° angle of attack;

[0017] Figure 6 Comparison of two-dimensional velocity vector diagrams of a leading-edge slit parachute and a conventional parachute at a 14° angle of attack.

[0018] Reference numerals: 1-Upper wing surface, 2-Lower wing surface, 3-Slat, 4-Rib, 5-Leading edge notch. Detailed Implementation Plan

[0019] To enable those skilled in the art to better understand the technical solution of the present invention, the implementation of the present invention will be further described in detail below with reference to the accompanying drawings.

[0020] like Figure 1 The diagram shows a three-dimensional outline of a high-gliding parachute with leading-edge slats according to the present invention. The parachute as a whole is composed of several air-cell-slat units. Figure 2 The diagram shown is a cross-sectional view of a high-gliding parachute canopy with leading-edge slats according to the present invention. The positions of the leading-edge slats 3, the leading-edge cutouts 5, the upper wing surface 1, and the lower wing surface 2 are as follows. Figure 1 As shown.

[0021] The canopy of this invention consists of an upper wing surface 1 and a lower wing surface 2, connected in the middle by ribs 4 to form an air chamber. The canopy is made of an airtight or low-permeability fabric. The rear edge of the canopy is sewn together, and a leading edge slit 5 is provided at the front edge. During operation, the air chamber is inflated to maintain the wing shape.

[0022] A slat 3 is provided at the front edge cut of the upper wing. The two sides of the slat 3 are stitched to the air chambers along their spanwise direction. The spanwise length of the slat 3 is longer than the width of the air chamber. The width of the leading edge of the slat 3 can be 120% to 140% of the spanwise length of the air chamber. The spanwise length of the trailing edge of the slat 3 is slightly smaller than that of the leading edge, and can be 110% to 120% of the spanwise length of the air chamber. The front end of the leading edge slat 3 is flush with the canopy cut, and the chord length of the slat is 8% to 15% of the chord length of the wing canopy. When the wing canopy is in operation, the slat 3 bulges in an arch shape, forming a gap between itself and the upper wing surface that allows airflow to pass through. This improves the airflow distribution on the upper wing surface of the wing canopy, delays airflow separation during high angle-of-attack flight, and increases the glide ratio of the wing canopy.

[0023] This invention also discloses a method for operating a high-altitude paraglider with leading-edge slats. Based on the aforementioned high-altitude paraglider with leading-edge slats, when the paraglider takes in air, the canopy expands, the air chamber quickly fills, and the leading-edge slats 3 open upwards, forming a bulge. Once the air chamber is full and generates sufficient lift, the paraglider begins to operate. A gap is formed between the leading-edge slats and the upper wing surface, allowing airflow to pass through. Airflow from the upper wing surface flows out through this gap, causing the leading-edge slats to bulge rapidly, improving the airflow distribution on the upper wing surface of the paraglider, delaying airflow separation during high angle-of-attack flight, and increasing the paraglider's glide ratio.

[0024] To better describe the technical gains of the high-gliding parachute with leading-edge slats of this invention, computational fluid dynamics is used to predict and analyze the aerodynamic characteristics of the parachute with leading-edge slats. To simplify the analysis, a flight flow field model is performed on a two-dimensional parachute cross-section. The relative velocity of the parachute to the incoming flow is 15 m / s, and the air density is 1.225 kg / m³. 3 The flow field calculations employed the SA turbulence model, a second-order upwind scheme, and the simple algorithm.

[0025] Figure 3 The graph compares the lift coefficients of paragliders with leading-edge slats and conventional paragliders. The graph shows that within the effective operating angle of attack range of 4° to 14°, the lift coefficient of the paraglider with leading-edge slats is significantly improved, reaching a maximum of 1.51, a 15% increase compared to the 1.31 of the conventional paraglider. Furthermore, the lift coefficient is significantly improved at high angles of attack, increasing by 17% at 14° compared to the conventional paraglider. This indicates that the leading-edge slats enhance the operating angle of attack envelope of the paraglider, enabling gliding and control over a wider angle of attack range, increasing the flight stability of the paraglider system, and making paraglider flight more reliable.

[0026] Figure 4 This is a comparison of the lift-to-drag ratio of a leading-edge slat paraglider of the present invention with that of a conventional paraglider. As can be seen from the figure, the leading-edge slat paraglider exhibits a significantly improved lift-to-drag ratio, with a maximum lift-to-drag ratio of 12.6, representing a 9% increase compared to the conventional paraglider. At angles of attack of 12° and 14°, the lift-to-drag ratio of the leading-edge slat paraglider is more than 10% higher than that of the conventional paraglider, indicating that the slat paraglider can improve the aerodynamic performance of paragliders at high angles of attack.

[0027] To further demonstrate the principle behind how slatted structures on the upper wing surface improve the high angle-of-attack gliding performance of a parachute, Figure 5 A comparison of two-dimensional pressure cloud maps of a leading-edge slat parachute and a conventional parachute at a 14° angle of attack shows that the leading-edge slats have little impact on the pressure inside the air chamber, allowing the air chamber to remain inflated at high angles of attack. Because the slats create a narrow airflow channel at the leading edge of the upper wing, the kinetic energy of the airflow over the leading-edge slats increases, while the pressure potential energy decreases. Therefore, the leading-edge pressure of the leading-edge slat parachute is lower than that of a conventional parachute. Figure 6 Comparing the streamline diagrams of a leading-edge slat parachute and a conventional parachute at a 14° angle of attack, the conventional parachute exhibits significant airflow separation on its upper surface. In contrast, the leading-edge slat parachute, due to increased kinetic energy on its upper surface, experiences a significantly reduced separation vortex and a markedly rearward shift in its separation point. Consequently, the leading-edge slat parachute achieves a substantial improvement in gliding performance at high angles of attack.

[0028] The above are merely preferred embodiments of the present invention. The scope of protection of the present invention is not limited to the above embodiments. All technical solutions falling within the scope of the present invention's concept are within the scope of protection of the present invention. It should be noted that for those skilled in the art, any modifications and refinements made without departing from the principle of the present invention should be considered within the scope of protection of the present invention.

Claims

1. A high-altitude glider with leading-edge slats, characterized in that: The paraglider is composed of several air chamber-slat units. The paraglider canopy configuration includes the paraglider canopy and leading edge slats. The canopy is divided into an upper wing surface and a lower wing surface. The upper and lower wing surfaces are connected by ribs to form an air chamber. The trailing edge of the canopy is sewn together, and a slit is set at the leading edge. When in operation, the air chamber is inflated to maintain the wing shape. The leading edge slat is set at the slit at the leading edge of the upper wing surface. The two sides of the leading edge slat along the chord direction are sewn to the upper wing surface fabric and ribs, while its leading and trailing edges are not sewn to the wing surface. The slat is sewn to the corresponding air chamber. The spanwise length of the slat is longer than the width of the air chamber. Specifically, the leading edge width of the slat fabric block is 120% to 140% of the spanwise length of the air chamber, so that when the high-gliding paraglider is in operation, the slat bulge is arched, forming a gap between it and the upper wing surface that allows airflow to pass through.

2. A high-altitude glider with leading-edge slats according to claim 1, characterized in that: The leading edge slats are sewn to the upper wing fabric and ribs of the parachute along the chord direction by a rolled or flat stitch, and reinforcing strips are provided on the leading and trailing edges.

3. A high-altitude glider with leading-edge slats according to claim 2, characterized in that: When the parachute is folded, the slats are close to the upper wing surface. When the parachute is fully open, the slats bulge, forming an airflow channel between them and the upper wing surface. The height of the channel is determined by the spanwise length of the slats.

4. A high-altitude glider with leading-edge slats according to claim 3, characterized in that: The trailing edge spanwise length of the slat is less than that of the leading edge, and is 110% to 120% of the spanwise length of the air intake chamber.

5. A high-altitude glider with leading-edge slats according to claim 3 or 4, characterized in that: The leading edge slat is flush with the canopy cut, and the chord length of the slat is 8% to 15% of the canopy chord length.

6. A high-altitude glider with leading-edge slats according to claim 1, characterized in that: The canopy and leading edge seams are made of non-breathable fabric blocks.

7. A method for operating a high-altitude paraglider with leading-edge slats, characterized in that: According to any one of claims 1-6, the paraglider with leading-edge slats, when the paraglider takes in air, the canopy expands, the air chamber quickly fills, the leading-edge slats open upwards and form a bulge, and the paraglider begins to work after the air chamber is full and generates sufficient lift; a gap is formed between the leading-edge slats and the upper wing surface to allow airflow to pass through, and the airflow from the upper wing surface flows out through the gap, causing the leading-edge slats to bulge rapidly, improving the airflow distribution on the upper wing surface of the paraglider, delaying airflow separation during high angle-of-attack flight, and increasing the paraglider's glide ratio.

Images