The invention relates to a canopy, in particular for a paraglider, parachute, flexkite, or surfkite, comprising an upper sail and a lower sail as well as profile-forming ribs.
The canopy in accordance with the present invention should relate to any desired canopies such as are used in paragliders, parachutes, flexkites or surfkites. Corresponding canopies for models, that is for parachute models, flexkite models, etc., for example, should also be included. Pulling sails for ships and kites for high energy acquisition and also canopies used in sailboats such as have become known under the name parasailor are included in the same manner.
The term canopy, for example in a paraglider, is as a rule used as an umbrella term for the complete piece of equipment, that is, for example, the equipment of the paraglider that essentially comprises a canopy, for example the paraglider canopy, that is connected by lines to the harness receiving the pilot. The canopy has a respective two-layer airfoil that is divided into an upper sail and a lower sail and is frequently produced from a nylon material. Perpendicular ribs that divide the total inner space of the canopy into a plurality of chambers disposed in parallel with one another in the direction of flight are incorporated between the upper sail and the lower sail to create the profile of the canopy.
Ideal flight properties or an ideal lift generation is adopted on a generation of a profile of the canopy similar to an airfoil. One or more inlet openings are arranged at the front edge of the canopy, also called the leading edge, and air moves via said inlet openings into the interior of the canopy and is accumulated there. The resulting excess pressure in the interior of the chamber provides the desired profile creation of the paraglider.
The chambers shaped in the direction of flight of the currently used paraglider canopies and parachute canopies are continuously filled via the front intake openings using the ram pressure principle in the opening and flight phases to generate an aerodynamically favorable profile shape. When the canopy is raised in the start phase, in particular with little headwind, the filling process up to the forming of a bearing profile in the zenith is particularly critical. On the one hand, the generation of the required ram pressure (forward speed) by the active arm movement and running movement of the pilot requires a high effort. On the other hand, the asymmetrical profile generates a buckling torque that often leads to so-called sail overshoot and thus to the aborting of the start.
In the flight phase of paragliders, so-called collapsing of the paraglider sail caused by turbulence is particularly critical. In this process, the inner pressure of the double sail collapses over wide areas and loses its aerodynamic lift function. The refilling of the chambers requires a lot of time and generates a high loss of up to 100 m. This phase is characterized by a high fall velocity and a tendency to rotate. This phase corresponds to the opening procedure of a parachute. The swing tendency during the opening phase is particularly critical here. In some emergency situations, the pilot or the canopy is no longer able to reactivate the filling procedure or to end the rotation so that serious accidents cannot be precluded.
It is the object of the present invention to further develop a canopy of the category such that critical situations in flight are largely avoided.
This object is achieved in accordance with the invention by the combination of the features of claim 1. For this purpose, a canopy that comprises an upper sail and a lower sail and ribs forming a profile is further developed such that at least two separate pressure zones are formed in the canopy that have different opening and emptying sides.
In accordance with the invention, a filling and emptying of the canopy optimized for the flight phase is made possible by the provision of the two separate pressure zones within the canopy that have different opening and emptying times. A control and extreme improvement of the aerodynamic properties of the canopy with respect to the physics of flight is thus provided in abnormal flight phases, on the raising of the canopy, on the start, and on the opening of the canopy. As a result borderline situations are defused, the height loss in the event of a disturbance, and the effort on the raising are substantially reduced, the filling phase up to the lift phase is decisively cut and the overshoot of the canopy on the starting procedure or the swinging of a parachute are prevented.
Further preferred aspects of the invention result from the dependent claims following on from the main claim.
The pressure zones are advantageously formed by cells.
The cells are advantageously formed by transverse ribs that enable an air exchange between the pressure zones.
The air exchange between the pressure zones can advantageously take place through openings and/or valves in the transverse ribs.
The air exchange between the pressure zones can be set by the dimensioning of the openings and/or valves such that different opening and closing times result in the cells.
Alternatively, the two or more pressure zones can also be separated from one another in an airtight manner; the transverse ribs accordingly mutually seal the cells/pressure zones. In this case the ventilation/venting of the pressure zones preferably takes place via separate openings and/or valves through which air can flow from the outside into the pressure zone or through which air can escape. The separate openings and/or valves are ideally dimensioned such that different opening and emptying times result for the pressure zones/cells.
The cells disposed at the front in the direction of inflow are advantageously filled faster than the rear cells during the filling. It is hereby prevented, in particular at the start, that a paraglider canopy overshoots, for example. Furthermore, no leveraging takes place and a smaller effort is required for raising.
In accordance with a further advantageous aspect of the invention, the cells disposed at the rear in the direction of inflow are emptied more slowly than the front cells during emptying. A higher buckling stiffness of the total canopy is hereby reached. No rotation or only very slight rotation after collapse takes place. The reopening of the canopy is substantially accelerated. Finally, the height loss is substantially reduced.
The invention finally relates to a paraglider, parachute, flexkite, or surfkite comprising a canopy that comprises the aforesaid features.
Further features, details and advantages of the invention will be explained in more detail with reference to an embodiment shown in the drawing.
There are shown:
A canopy 10 is now shown during the start process in the filling phase in
The cross-section of the canopy 10 in normal flight is shown in
The corresponding buckling behavior of a canopy is shown in a conventional embodiment in
In comparison with this, the collapse line and the deformed surface in the system in accordance with the invention are shown in
A higher buckling stability is here achieved by the two pressure zones and by the cells hereby formed that results in more stable flight characteristics on this disturbance.
The inner pressure progression of a conventional canopy 10 of a traditional paraglider over time (bottom curve) is compared with the inner pressure progression of a canopy 10 in accordance with the invention in
It can initially be recognized in the plan view in
Different arrangements for the separate pressure zones 34, 36, 38, and 39 are now shown in
Alternatively to the embodiment shown, the individual pressure zones 30, 32 could also be closed in an airtight manner with respect to one another, i.e. the transverse ribs 22 and/or the ribs do not provide any openings/valves for the air exchange. A separate inlet opening would have to be provided for ventilation/venting the pressure zone 32 in this case, said inlet opening being introduced, for example, just behind the transverse rib 22 at the lower sail 14 in the direction of inflow. The previously mentioned flight characteristics are achieved by suitable dimensioning of the two inlet openings.
Number | Date | Country | Kind |
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20 2015 005 513.3 | Aug 2015 | DE | national |
Filing Document | Filing Date | Country | Kind |
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PCT/EP2016/001300 | 7/27/2016 | WO | 00 |