IL152515A

IL152515A - Parachute slider with nozzles

Info

Publication number: IL152515A
Application number: IL152515A
Authority: IL
Original assignee: Parachutes De France S A
Priority date: 2001-11-05
Filing date: 2002-10-28
Publication date: 2006-06-11
Also published as: CA2409591A1; ATE316493T1; FR2831869B1; DE60208871D1; KR100837437B1; NO20025236D0; EP1308386B1; JP2003146296A; IL152515A0; EP1308386A1; KR20030038402A; NO20025236L; FR2831869A1

Abstract

The pilot chute (1) for a parachute or inflatable supple wing comprises a flat or domed panel with its underside (2) bordered by a hem (4) with fixing points (3) spaced sufficiently far apart to allow the hem to open under the action of an air flow applied to the underside, leading to a progressive opening of the canopy at high altitude. The fixing points are in the form of eyelets through which the parachute lines pass.

Description

A parachute slider with nozzles Parachutes De France S.A.

C. 141450 A PARACHUTE SLIDER WITH NOZZLES The present invention relates to a parachute slider enabling the canopy of a round type or of a flexible inflated wing type parachute to be opened progressively, the slider comprising a plane or bell -shaped sheet having a face that forms a concave surface.

The invention applies to parachutes for loads or for people, and more particularly it relates to parachutes for release at very high altitude, for example ,000 meters (m) or 12,000 m, but it could also be applied to parachutes for release at the usual altitudes below 6000 m.

After release, but before the canopy of the parachute has been deployed, such a slider is deployed automatically during a "time delay" stage in order to slow down the descent of the parachute and enable its canopy to be deployed at a speed that is slow enough, and subsequently it is retracted after the canopy of the parachute has been fully deployed. More particularly, with a parachute, the load is suspended from the canopy by a plurality of suspension lines. The top ends of the suspension lines are fixed to a bottom portion of the canopy, with the fixing points being distributed over said bottom portion. The bottom ends of the suspension lines are grouped together in a plurality of groups, each group of suspension lines being connected to the load via a riser. The slider is interposed between the canopy and the load and generally has a plurality of eyelets through which bundles of suspension lines pass. During the time delay, the aerodynamic flow exerts pressure on the concave side of the slider, thereby restraining the flow of air penetrating into the canopy and enabling it to open progressively and at slow speed. During deployment of the parachute canopy, the suspension lines tend to move apart from one another, which has the effect of pushing the slider down towards the load where it can be retracted.

The sliders presently in use are designed for release at altitudes of less than 6000 m and for loads of up to 200 kilograms (kg) . When. releasing at very high altitude, e.g. between 10,000 m and 12,000 m, and for loads that are heavier, the speed in free fall becomes so great that the sliders presently in use no longer operate correctly. In particular, it has been found that under such conditions of use, the slider tends to take up an oblique position beneath the canopy so that its slowing-down action is significantly diminished or even nonexistent. As a result, the parachute canopy can open suddenly which can be dangerous for people and/or damaging to the load being transported.

The object of the invention is to remedy that drawback by proposing an improved parachute slider suitable for operating at high altitude and at high speed.

To this end, the invention provides a slider for a parachute, the slider comprising a plane or bell-shaped sheet having one face that forms a concave side, the slider being characterized in that the margin of the concave side of said sheet carries a peripheral hem fixed to the sheet at a plurality of fixing points which are spaced apart from one another by a distance which is sufficient for the peripheral hem to gape open between the fixing points under the action of a flow of air directed towards the concave side. Such a slider in place on a canopy in the opening situation captures the dynamic pressure of the air flow. This extra pressure deforms the hem which gapes open into the form of nozzles distributed around the outline of the slider. These nozzles formed in this way provide better control over deflection of the flow of air blown into the canopy, by establishing maximum suction above the slider. The canopy can thus remain stabilized during a time delay stage that is relatively lengthy, enabling the canopy to be deployed at a sinking speed that is sufficiently slow.

Thereafter, inflation of the parachute canopy is enabled by an air admission opening formed in the sheet of the slider, this opening possibly being calibrated so as to break the equilibrium at the end of the time delay stage and cause the canopy to inflate progressively.

Each point where the hem is fixed to the concave side of the slider can be formed by an eyelet crimped in the hem and in the sheet, or else it can be formed by stitching. The slider sheet may be square, rectangular, round, or polygonal in outline or its shape may be identical to the plane shape of the parachute canopy. The air admission opening into the slider sheet can be of any appropriate shape, e.g. round, square, rectangular, in the form of a single slot, or in the form of a cross. It can be centered or off-center and it can optionally be variable in size. A tube of nozzle- forming cloth can be fixed to the convex side of the slider around the edge of the air admission opening so as to direct the air flow inflating the canopy at a particular angle or towards a particular point of the canopy. The slider sheet can comprise a single layer or a plurality of layers. The hem and the sheet of the slider may be formed as a single piece, in which case the hem is formed by sheet margins folded over onto its concave side. The hem may also be a separate piece fitted to the sheet of the slider. To obtain a satisfactory nozzle effect, the width of the hem should lie in the range 6% to 25% of the width or the depth of the slider.

The invention is described in greater detail below and is shown in the accompanying drawings, in which: Figure 1 is a view from beneath of an embodiment of a slider in accordance with the invention; Figure 2 is a view from beneath of the slider shown in Figure 1 when subjected to a flow of air directed towards its concave side; Figure 3 is a profile view of the slider shown in Figure 1 while it is subjected to a flow of air directed towards its concave side; Figure 4 shows a variant of the invention in which the fixing points are tabs sewn to the sheet and the hem; Figure 5 shows the shape to which a piece of sheet should be cut to make a slider of the invention; Figure 6 shows how air flows under the concave side of a slider of the invention; Figure 7 shows how air flows under the concave side of a prior art slider; Figure 8 shows a slider of the invention of hexagonal peripheral outline; Figure 9 is a perspective view of a slider of the invention with an air admission opening provided with a nozzle-forming tube of cloth; and Figure 10 shows a slider of the invention of outline that is identical in shape t.o the plane shape of a parachute having a wing-type canopy.

As can be seen in Figure 1, the slider 1 is constituted by a sheet 1' of cloth having a face 2 that constitutes a concave side. The sheet may be plane or it may be bell-shaped. The slider has a plurality of eyelets 3 around its outline through which groups of parachute suspension lines are to be passed. In the example of Figure 1, the slider has an outline that is square and the eyelets are placed in the corners of the outline, but other shapes can be envisaged, for example various polygonal shapes.

In the invention, the sheet 1' has a peripheral hem 4 occupying the margin of its concave side, with the inside edge of the hem being secured to the sheet at a plurality of distinct fixing points. These fixing points are spaced apart from one another by a distance which is sufficient to ensure that the peripheral hem 4 is free to gape open between two successive fixing points when the slider is subjected to a flow of air directed towards its concave side 2. When the slider is deployed and subjected to such a flow of air, the peripheral hem 4 gapes open between the fixing points so as to form nozzles T that direct the air flow radially. As can be seen in Figures 2 and 3, the peripheral hem 4 gapes between its adjacent fixing points which are constituted in this case by eyelets 3 disposed around the periphery of the slider and through which the parachute suspension lines pass. With this arrangement, the flow of air inflating the parachute canopy is reduced, thereby lengthening the time delay prior to full deployment of the canopy. It has also been found that because the nozzles T eject air radially as shown by arrows F, forces are distributed more evenly on the slider, thus preventing it from taking up an oblique position. By way of example, the width of the hem t can lie in the range 6% to 25% the width L or depth of the slider.

In a variant embodiment shown in Figure 4 , the fixing points are constituted by cloth tabs 31 sewn to the peripheral hem 4 and to the cloth 1'. Each tab is provided with a ring 3" positioned on the outside edge of the slider and intended to have the suspension lines of the parachute passing therethrough.

In Figures 6 and 7, the path followed by the streams of air F during the time delay stage are shown respectively with a slider of the invention and with a prior art slider. The streams of air F press the slider 1 against the top ends of the suspension lines 6 which are fixed to the canopy 5. In the prior art, the air escaping from the slider 1 goes round the convex side 2 so as to escape vertically and inflate the canopy 5 as shown in Figure 7, whereas in the invention, the air is channeled radially by the nozzles formed by the peripheral hem 4 gaping open so that said air goes round the canopy 5 without penetrating into it, as can be seen in Figure 6.

Advantageously, the slider of the invention may have an air admission opening 7 passing through the sheet 1 ' , as shown in Figure 2. This air admission opening 7 is designed to allow some air to pass through the slider into the canopy during the time delay stage so as to inflate the canopy progressively. With this arrangement, the duration of the time delay stage can be directly adjusted by modifying the shape or the size of the air admission opening 7 so as to increase or decrease the rate at which air flows into the canopy. This air admission opening may be round, square, or rectangular in shape, or indeed it may comprise a straight slot or a slot in the form of a cross. This air admission opening 7 may be placed in the center of the sheet 1 ' or it may be off-center so as to inject air into a particular portion of the canopy during the time delay stage. In a particular embodiment shown in Figure 9, a tube of sheet 8 is sewn to the edge of the air admission opening 7 on the convex side of the slider so as to form a nozzle for directing the air penetrating into the canopy more accurately. This arrangement serves in particular to inflate and deploy the canopy with a predetermined sequence by directing air towards a particular zone of the canopy.

As mentioned above, the points where the hem 4 is fixed to the sheet 11 can be eyelets crimped in the sheet or indeed tabs sewn to the sheet and provided with rings. The eyelets and rings can have the suspension lines of the parachute passing through them.

Figure 5 shows an example of the shape to which a sheet can be cut in order to make a slider of the invention that is substantially square in shape, on the basis of a single piece of cut sheet. In this example, the peripheral hem 4 is made by a double fold for placing against the concave side 2. This double fold increases the mechanical strength of the hem, enabling it to withstand aerodynamic forces. The peripheral hem could also be constituted by a separate piece of sheet that is applied by being sewn to the periphery of the concave side 2.

In the example shown in Figures 1 to 5, the slider of the invention is substantially square in shape having four eyelets or rings, however it can be adapted to other conventional shapes, for example a hexagonal shape having six eyelets or rings as shown in Figure 8. More generally, the slider may be polygonal in shape having a fixing point for the hem on the concave side of the slider situated at each vertex of the polygon. The slider may also be adapted to other shapes, for example it may have the plane shape of a substantially rectangular parachute wing, with an eyelet or a tab having a ring at each vertex of the rectangle, as shown in Figure 10. 8

Claims

1. CLAIMS 1 / A slider for a parachute ( 5^ , the slider comprising a plane or bell-shaped sheet ( ^) having one face that forms a concave side , the slider being characterized ide N ) of said sheet ixed to the sheet which are spaced apart from one another by a distance which is sufficient for the peripheral hem to gape open between the fixing points under the action >f a flow of air directed towards the concave side (< 2/ A slider according to claim 1, in which each fixing point is formed by an eyelet crimped to the peripheral hem and the sheet ) , each eyelet serving to pass suspension lines of the parachute . 4/ A slider according to any one of claims 1 to 3 , having an air admission opening passing through the sheet 5/ A slider according to claim 4, in which the air admission opening is round, square, rectangular, or slot-shaped. 6/ A slider according to claim 4 or claim 5, in which the air admission opening (^ is off-center. 7/ A slider according to claim 4 , having a tube of cloth fixed to the convex side of the sheet around the edge of the air admission opening ( ) . 8/ A slider acorn to any one of claims 1 to 7, in which the peripheral hem and the . sheet CS^ ) constitute a single piece. 9/ A slider according to any one of claims 1 to 7, in which the peripheral hem ^ is a piece fitted to the sheet . 10/ A slider according to any one of claims 1 to 9, in which is polygonal in outline, each fixing point posed at a vertex of the polygon. 11/ A slider acorn to any one of claims 1 to 10, in which the hem is of a width lying in the range 6% to 25% of the width or the depth of the slider. For the Applicants EINHOLD COHN AND PARTNERS By ;