MXPA01006867A - Pneumatic float for light and ultralight aircraft - Google Patents

Abstract

The inventive pneumatic float consists of an airtight outer skin (5) which can be exposed to compressed air through a valve (21). Webs (6) that are connected to the outer skin (6) along the lines (1) extend over essentially the entire length of the float. Said webs divide the inside of the float into intercommunicating chambers (7) and provide the float with its required contour (14), stability and flexural strength. The webs can be single or multiple-layered and consist of only slightly stretchable fabric or plastic films. The inventive float also has a keel section (8), which may consist of plastic, for example, and which is attached by adhesion, for improving directional stability during operation and for preventing damage to the outer skin (5). Two side sections (9) are mounted in the same way to prevent the Coanda Effect.

Description

"A PNEUMATIC FLOAT FOR LIGHT AND ULTRA-LIGHT AIRCRAFT" The present invention relates to a pneumatic float for light and ultra-light aircraft, in accordance with the preamble related to Claim 1. Several of these pneumatic floats are known, which are inflated with compressed air. The most similar to the present invention, which represent the state of the technology, are published for example in U.S. Patent Number 4,697,762 (DI), U.S. Patent Number 2,391,326 (D2), U.S. Patent Number 2,522,340 (D3) and U.S. Patent Number 2,345,143 (D4) Even though in D2, D3 and D4 the general state of the technology is limited, DI is the most similar to the present invention. A float is published in DI, comprising a flexible outer hull of strong woven fabric, which is constructed of an upper side, a lower side and side walls. The upper and lower sides are joined by a number of textile fabrics constructed in a similar manner in an essentially vertical direction and along the main direction of the float. In a position somewhat towards the back of the center, the float has a step, - which was published in Patent Number DE 600 321 from 1933, and has been applied and further developed since then. In the transverse section through the float in the Patent ID at the position of this mentioned step, a substantially vertical fabric is constructed in a similar manner, however in a direction perpendicular to the main direction of the float. In the chambers, which are formed between the fabrics and between the fabrics and the side walls, airtight bladders are inserted that are inflated with compressed air and provide the float, on the one hand, with the necessary flotation and on the other hand, a certain stability . To increase the stability and rigidity, stiffening elements are constructed in the region in front of the aforementioned step, which are partially provided with rigid foam, partially of plywood. A shoe is attached to the exterior of the float made of fabric, which also provides rigidity to the underside of the front part and is to protect the float from damage. This shoe is manufactured, for example, from plastic material. The introduction of the force from the bottom carriage of the airplane to the two floats constructed as described, occurs through two longitudinal beams that run longitudinally over the entire length of - each float These are on the side at the top of the floats and are tied and fastened by long ties. The total of four beams are joined by two transverse spars where the aircraft is supported, whereby the rear transverse spar is more or less in the position where the lower side of the float has the mentioned step. If the proposed application area of the float is taken into account in accordance with the DI Patent, then the main advantage claimed is the conservation of weight. Since the selected method of construction of the float-only pneumatic part has, however, insufficient stiffness, all kinds of measures which are not pneumatic, and therefore heavier, in part, of course, essentially have to be provided for this increase. heavier than air, or purely pneumatic components. In addition, at the height of the step, the longitudinal tissues are interrupted by a transversal fabric. Due to the introduction of the force of the rear transverse beam that is also more or less at this point, this region results in a weakening similar to a float joint in one of the constructions claimed in the Patent ID which has to be reinforced and tensioned by a compression leg that passes vertically through the float and two wire ropes. Nor is it evident from the DI Patent, the manner in which another cross-section is formed - for example such as those with a "V" -shaped bottom part or part - which can be constructed in accordance with the invention. Of the selected construction, it can be anticipated at least that, in addition to the aforementioned disadvantages, the float according to the ID Patent can not be manufactured economically either. Therefore, the aim of the present invention is to produce pneumatic floats for light and ultra-light aircraft, which overcome the disadvantages shown, which are light and rigid and which can also be manufactured cost-effectively. The focus of the stated aim is reproduced in Claim 1, with respect to its essential features, in the following claims with respect to additional advantageous embodiments. The invention is described more similarly using the attached drawing. Shown are: Figure 1 a perspective view of a first embodiment, Figure 2 a cross section through the first embodiment, - Figure 3 a construction detail of Figure 2, Figure 4 a supplement to Figure 2, according to the invention, Figure 5 a section through a second embodiment, Figure 6a a side view of the first embodiment, Figure 6b a longitudinal section through a detail of Figure 6a, Figure 7 a schematic perspective view through the first embodiment. Figure 1 is an oblique view from below the front of a mode of a float according to the invention. Only the purely pneumatic structure is shown here without all the fastening and joining parts. In the representation in Figure 1, it appears on lines 1, which run along the float, which are explained more similarly using Figure 2. About half the length of the float you can see a step 2 which - as is known - is provided to detach the flow of water. The bow of the float shown on the left in Figure 1 has a front face 3, the stern on the right has a similar end surface 4. Figure 2 is a typical cross-section through the float of Figure 1, plus or except in the position marked AA. An external coating 5, which - it comprises a woven material of low elongation laminated hermetically is inflated with compressed air through a valve 21 and is maintained in the manner proposed by a multiplicity of fabrics 6, which are bonded with the outer coating 5 essentially over its entire length. These joints can be created by sewing, gumming or welding. Where the fabrics 6 are attached to the outer liner 5 in the manner described in the lines 1 mentioned in the association with Figure 1, they are raised, which extend essentially over the entire length of the float. The fabrics 6 may comprise woven fabrics or also thin sheets of metal; which divide the internal space of the float into chambers 7, which communicate with each other. For this purpose, the fabrics 6 are not completely taken up to the arc and stern surfaces 3, 4 so that at least at the two ends of the float, overflow gates (not shown) are present. This is especially important with the use of air-tight thin sheets of metal for the fabrics 6. With the use of woven fabrics for the fabrics 6, the air exchange between the chambers 7 is provided by the material. If a textile insert is used then the path of the fibers of the fabric is placed in parallel and perpendicular to the axis - - Longitudinal of the float. It has also been shown that it is advantageous to insert the woven fabric into a double layer, whereby one layer is rotated with respect to the other by approximately 45 °. In this way the fabrics 6 remain in position also when knitted textiles are used, to accept shear stresses, which intensely increases the stiffness against bending and the stability of the shape of the float. In the keel region in this first embodiment, a keel rail 8 is fixed, either by gluing or welding, which on the one hand improves the directional stability of the float and on the other hand protects its lower surface against damage. In a similar manner, the side rails 9 are fixed to the transition from the bottom surface to the side walls of the float. Its object also comprises the protection of the external coating 5 the prevention of the so-called Coanda effect in water, and therefore also provide means for the detachment of the flow. The keel rail 8 and the side rails 9 are preferably made of plastic material. The side rails 9 extend, for example only above the front part of the float, that is, from the arch to the step 2; the keel rail 8 extends similarly above the front of the float, but nevertheless, it can also be applied to the back of step 2. With the number and density of the fabrics 6 shown in the drawing, its diren is obtained by the application of osculation circles 10 as shown in Figure 3. Figure 3 is a sen of Figure 2. In the proposed total 11 outline of the cross sen, the osculation circle 10 is inserted. in such a way that it is brought into contact with the total contour at the first predetermined points 12. The second contact points 13 are then calculated for the total contour 11 of elementary geometrical considerations. The contact points 12, 13 of each osculation circle 10 join together and provide the diren of the tissue 6 to be inserted here. The actual contour of the cross sen in the condition of the float when inflated with compressed air results from the equation of the forces that are established at each of the contact points 12, 13. This actual contour of the outer skin 5, as shown in FIG. shown in Figure 2 and to which the reference number 14 is given, it then comprises the segments of the circles that meet at contact points 12 and 13, whose radii are determined by the well-known relationship s R =? p in where R = radius of curvature [m] s = circumferential tension in the outer sheath 5 [N / m]? p = difference of inner-outer pressure [N / m2] However, since, s is proportional to? p, of the elementary physical derivation results a value for R which depends only on the geometry of the individual cameras 7 and in the order of magnitude of their semi-diagonals. Figure 4 shows a further particularity in accordance with the invention, again in the first embodiment. The outer coating 5, as already mentioned, becomes airtight and can be inflated with compressed air through the valves, for example on the end surface 4. In this way the entire float remains under pressure, the tissues 6 they stretch and adopt the task of providing rigidity to the float longitudinally, so that additional stiffening means are not necessary. For the eventuality only of a loss of pressure due to local damage to the outer skin 5, flexible elastic bladders 15 are inserted in the chambers 7 between the outer skin 5 and the tissues 6, which under normal operation are pumped up to 80% at 90 percent of the air pressure acting on the outer sheath 5, air tight. In normal operation, therefore, these bladders do not perform any function. However, if a loss of pressure occurs within the outer lining 5, but outside the bladders 15, then the bladders are against the walls of the chambers 7 and ensure that the static of the float is essentially retained. Each bladder 15 has its own valve 16; these are preferably placed similarly on the end surface 4 and are preferably configured as non-return valves. If one of these bladders presents an escape or otherwise is damaged, then the remaining bladders 15 are not affected by this. These valves 16 are preferably taken towards a duplicate (not shown) for the equal setting of the pressure acting within the bladders 15. It is shown in Figure 5 that the configuration of the cross-section is not restricted to that shown in FIGS. Figures 2, 3 and 4. A twin keel float within the scope of the invention is shown here - - as a second modality. The total contour 11 can be prescribed and modified by inserting the tissues 6 according to the invention. Configuration optimization is possible by carrying out several of these iterative steps. One configuration, as shown in Figure 5, is greater than one according to Figures 1 to 3 with respect to spraying conditions. Due to the relatively large inclination of the outer tissues 6, stability around the horizontal transverse axis deteriorates to a certain degree, but that around the vertical transverse axis is increased. For the directional stabilization in the operation and as protection against damage to the underside of the float, two keel rails 8 are provided here which correspond to their configuration. The side rails 9 present in a similar manner serve to suppress the Coanda effect that arises most intensely in this form of construction. In addition, they carry out, as already mentioned above, a similar protection function against damage to their outer coating 5 on the sides. Figure 6a is a side view of the first embodiment of a float according to the invention, Figure 6b is a longitudinal section through the - - step 2, as indicated. The longitudinal section through the float here shows a continuous transition above the cross section covering the step, as shown by the lines 1 flowing uniformly shown in dashes. In this way, the tension ridges of the outer covering 5 and the tissues 6 due to bending force in the float are avoided, which, with a discontinuity would otherwise be unavoidable. The step 2 itself comprises, for example, a helmet 17 of plastic material which is filled with a hard foam 18 and is glued to the outer coating 5 under positive coupling. The helmet 17 of plastic material is further coated with a protective layer 19 which advantageously covers the entire underside of the float. In this way, a uniform distribution from the front of the float to the helmet 17 of plastic material is ensured. Figure 7 shows the stroke of the fabrics 6 over the entire length of a float according to the first embodiment. Seven cross-sectional surfaces 20 are attracted, however, they are of an irrelevant nature and in no way represent the fabrics or other types of transverse bulkhead, regardless of what type. It can be seen from Figure 7 that the configuration or shape of the surfaces - in cross-section is essentially the same in total, only their sizes are different. By separating from Figure 7, the part or piece of the float that lies behind the step 2 can obviously have a different shape from the bottom - and in the same way from the surfaces 20 in cross section - as long as the transitions of the shape or settings are uniform, taking into account the construction of step 2 shown in Figure 6a, b. This is, for example, the case in the second embodiment of the float according to the invention, wherein the part remaining behind the step 2 can also be constructed with a single keel. This especially taking into account the fact that the twin keel construction only provides its effectiveness in the front part or part. Constructions are known for the introduction of the static and dynamic loads of the airplane towards the float and between the floats. There are flat or rod-shaped structures that extend over a large part of the length of the float and link the two floats together. These constructions are as mentioned already known or result in a similar way of construction to the task of distributing the weight over the largest possible surfaces. These tasks usually present themselves when they have to - introduce the loads to the textile and / or pneumatic components.

Claims (15)

- CLAIMS

1. A pneumatic float for light and ultra-light aircraft, where the textile material and the flexible fabrics (6) are placed running longitudinally inside the float, whereby the chambers (7) are divided inside the float, inside which insert air-tight and flexible bladders (15), which can be inflated with compressed air, characterized in that - the float has an external air-tight and enclosed lining (5), - the float has a multiplicity of flexible fabrics (6) that they run essentially over their entire length, which are fastened to the outer covering (5) throughout its entire length, whereby the position and placement of the tissues (6) is established so that within a proposed total contour ( 11) of a cross section through the float, the osculation circles and the two contact points (12, 13) of each osculation circle are inserted in this total contour (11) defi In the fastening points of each fabric (6) to the outer covering (5), in the insertion of the fabrics (6) the intercommunication chambers (7) are erected between them - and the outer covering (5) each of which includes a flexible air-tight bladder (15) which can be inflated with compressed air, the external air-tight coating having at least one valve (21), through which It can be inflated with compressed air.

2. A pneumatic float according to claim 1, characterized in that the fabrics (6) are made of an elongation fabric whose fiber race is placed essentially parallel to and perpendicular to the longitudinal axis of the float.

3. A pneumatic float according to claim 2, characterized in that the fabrics (6) are present which are constructed of double walls, whereby the race of the fibers of the second layer of the textile material is rotated by 45 °. from the first.

4. A pneumatic float according to claim 1, characterized in that the fabrics (6) are made of thin sheets of plastic of low elongation.

5. A pneumatic float according to claim 2, 3 or 4, characterized in that the fabrics (6) are fastened to the outer covering (5) by sewing. - -

6. A pneumatic float according to claim 2, 3 or 4, characterized in that the fabrics (6) are fastened to the outer covering (5) by means of gumming.

7. A pneumatic float according to claim 2, 3 or 4, characterized in that the fabrics (6) are fastened to the outer covering (5) by welding.

8. A pneumatic float according to claim 1, characterized in that the bladders (15) comprise an air-tight laminated textile material of low elongation.

9. A pneumatic float according to claim 1, characterized in that the bladders (15) comprise an elastomer.

10. A pneumatic float according to claim 8 or claim 9, characterized in that each bladder (15) has a valve (16) that remains in the outer coating (5).

11. A pneumatic float according to claim 10, characterized in that the working pressure in the bladders (15) is between 10 percent and 20 percent less than those in the outer coating (5).

12. A pneumatic float according to claims 1 to 11, characterized in that the external coating (5) is provided with a protective layer (19) at least in the part that enters the water.

13. A pneumatic float according to claim 12, characterized in that the float comprises a front part and a rear part, whereby the transition from the front part to the rear part includes a step (2), wherein the fabrics (6). ) inside the float are configured in such a way that the surface in greater cross-section of the step (2) is continuously moved towards the smaller cross-section behind the step (2), - the external covering (5) bears a helmet of material plastic (17) forming the real step (2), which is filled, the protective layer (19) is taken over the step (2) and also covers the helmet made of plastic material.

14. A pneumatic float according to claim 12, characterized in that the float carries at least one keel rail (8) and two side rails (9) for the protection against damage of the float.

15. A pneumatic float according to claim 14, characterized in that the rails of - Keel (8) and side rails (9) comprise plastic material and are gummed on the float.