Aeronautics and astronautics – Safety lowering devices – Parachutes
Patent
1991-07-09
1992-12-22
Barefoot, Galen
Aeronautics and astronautics
Safety lowering devices
Parachutes
244145, B64D 1700
Patent
active
051728745
DESCRIPTION:
BRIEF SUMMARY
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a device for supplying air to a double-surface-aerodynamic-profile, and typically a paraglider or a parachute. More specifically, the device according to the invention is intended to permit the supply of air to the space situated between the lower surface and the upper surface of a parachute or of a paraglider.
2. Description of the Prior Art
Traditionally, this air supply is effected by an open space, provided at the front of the paraglider, and typically representing between 1 and 20% of the total surface area of the lower surface. This air supply between lower surface and upper surface is intended to permit the advance of the paraglider or of the parachute in a plane other than the purely vertical plane of the to gravity.
Paragliders are currently known which possess at the location of their forward zone, an a-jour fabric of "mosquito net" type, but the ventilation aperture surface area of which never exceeds 20% of the total surface area of the lower surface. Now, this supply zone exhibits a surface area which is insufficient under certain flight conditions. Moreover, this zone is partially or entirely blocked when the whole or part of the front of the appliance, i.e. paraglider or parachute, becomes folded, for example on account of aerological turbulences. Moreover, this forward zone is in some instances poorly ventilated along the direction which is adopted by the appliance, and the aerodynamic profile of the paraglider is then no longer ensured correctly, leading in certain instances to a significant fall of the appliance.
In the document EP-A-0,336,277, a paraglider has been proposed, the lower surface of which is equipped with a flap valve which is liable to give rise to pressure variations at the location of the space situated between the lower surface and the upper surface. Nevertheless, this system incorporating a flap valve does not permit the maintenance of a correct aerodynamic profile of the appliance. In fact, it generates at the location of the sail of the paraglider local variations of pressure which are unsuited to slight, as these may give rise to the folding of the sail. Moreover, when using such a system it has been possible to observe phenomena of autorotation, generally leading to the falling of the appliance.
SUMMARY OF THE INVENTION
The present invention aims at alleviating these various disadvantages. It relates to a safety device for supplying air to a double-surface-aerodynamic-profile. This device is characterized in that the lower surface area or lower surface is permeable to air over at least a part of its surface area.
Typically, the lower surface may be permeable to air over the whole or part of its surface area, depending upon the ultimate intended purpose of the appliance. Accordingly, this lower surface is pierced with orifices, the surface area of which is within the range between 0.001 mm.sup.2 and 4 mm.sup.2. In fact, it has been noted that if the surface area of these orifices were less than 0.001 mm.sup.2, the lower surface no longer exhibited sufficient permeability to air for the desired effect, and especially the effect of stabilization of the aero-dynamic-profile of the appliance and of advance of the appliance in a plane other than vertical or subvertical. On the other hand, if the surface area of the orifices of the lower surface is greater than 4 mm.sup.2, the lifting function of the lower surface is no longer ensured and, furthermore, the resultant advance of the appliance cannot take place under correct conditions.
In a particular embodiment of the invention, the lower surface is formed by a free air inlet situated at the location of the forward zone of the appliance, which zone is followed by a zone constructed of a fabric impermeable to air, similar to the upper surface, and finally a part referred to as "ventilated", that is to say permeable to air, in a zone which is to the rear in relation tot he aerodynamic-profile. This particular feature is more particularl
REFERENCES:
patent: 2993667 (1961-07-01), Cushman
patent: 3822844 (1984-07-01), Sutton
patent: 3944169 (1976-03-01), Beda
patent: 3972495 (1976-08-01), Jalbert
patent: 4253627 (1981-03-01), Matsao
patent: 4406433 (1983-09-01), Radkey et al.
patent: 4811920 (1989-03-01), Askwith et al.
Barefoot Galen
Ellis Christopher P.
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