RU2225328C2 - Method and device for forming lifting force - Google Patents

Abstract

FIELD: lighter-than-air flying vehicles. SUBSTANCE: proposed device has pneumatically strained envelope filled with air and made for change of density of air both by change of volume of envelope and amount of air contained in it. Pneumatic strain of envelope is ensured by tension of it on spiral structure formed by kevlar stiffeners. EFFECT: enhanced safety and reliability. 3 cl, 7 dwg, 3 ex

Description

 The invention relates to the field of creating aircraft lighter than air, in particular to the creation of devices that create a lifting force sufficient to move goods or people.

 A known method of creating a lifting force by pumping into a closed sealed sheath of light gas. To regulate the lifting force, a certain amount of ballast is dumped and a required amount of light gas is vented, see, for example, A. Chernov. Traveling by balloon. -L .: Gidrometeoizdat, 1975, p.27.

 The device for creating lifting force in this case contains the hermetic shell itself, devices for filling it with light gas, ballast and devices for dropping ballast and bleeding gas.

 The disadvantages of the data of the method and device primarily depend on the fact that a light gas, usually helium, is used. This gas is very volatile. It penetrates quite easily through the pores of many materials. Sealing is associated with great difficulties. In addition, light gases are usually quite expensive. There are also cheap gases, such as hydrogen. But its use is associated with the threat of explosion.

 A method has been developed for creating lifting force without the use of light gases and a device for implementing this method. In accordance with this method, air is pumped into the space between two concentric shells connected by transverse bonds to an excess pressure that ensures structural rigidity (no collapse under the influence of atmospheric pressure) when air is completely evacuated from the inner shell, see V. Brode. Aeronautical aircraft. -M .: Engineering, 1976, p. 89. The author of this book by calculations proves the impossibility of ensuring the buoyancy of such a structure, because the mass of air pumped under excessive pressure is equal to the mass of air removed from the inner space.

 A known method of creating lifting force and a device for its implementation, described in RF patent 2126342 for the invention of "Ballastless Balloon Aircraft", IPC B 64 V 1/62, claimed July 31, 1997, published February 20, 1999. The creation of lifting force is carried out by changing the density of air in an inner closed pneumatically stressed shell by changing its mass. The air pressure in the shell may be greater, less, and equal to atmospheric pressure. In order to prevent collapse under the influence of atmospheric pressure, the cavity between the inner and outer shells is filled with light gas under excess pressure above atmospheric pressure. The device, which is an aerostatic aircraft, contains a closed-circuit pneumatically stressed structure, formed from interconnected by means of force transverse connections of the outer and inner shells. The cavity between the shells is filled with light gas under excess pressure above atmospheric. The internal cavity is filled with air. There is a tool for changing the mass of air filling the internal cavity, including a bypass valve, a pump and a compressor.

 The disadvantages of the above method and device are primarily associated with the use of light gases: difficulties in sealing, high cost, explosion hazard.

 Known as a prototype device for creating a lifting force, containing a sealed flexible pneumatic-stressed shell forming a vacuum cavity, and a device for expanding the shell mounted on it. A device for expanding the shell is placed on the outside of the shell and is a sealed pneumatic element (a thin-walled hose laid on the entire surface of the shell in a spiral, adjacent turns of which are fastened together by at least one layer) with an internal drive chamber in communication with the source pressure. Power elements are placed inside the vacuum cavity.

 The prototype method, in accordance with which the prototype device operates, provides the creation of lifting force by changing the density of air in a closed pneumatic stressed shell by changing the volume of the shell.

The disadvantages of the prototype are:
- the use in the form of stiffening ribs of a pneumatically stressed hose under excessive air pressure, which makes it possible to efficiently use this device as a vacuum chamber, but cannot ensure the buoyancy of this structure in the atmosphere, because the amount of air pumped into the hose is equal to or higher than the amount of air displaced by the shell in the atmosphere (even without taking into account the weight of the shell and hose);
- unreliability of the structure due to the inability to provide the necessary strength of the hose to bend or break;
- when the shell breaks, the structure collapses, that is, safety is not ensured.

 The task of the claimed invention is to increase safety and reliability.

 This problem is solved due to the fact that in the known device for creating a lifting force containing a closed pneumatic stressed shell, configured to change the air density both by changing the volume of the shell cavity and by changing the amount of air in the shell cavity, according to the invention, the pneumatic tension of the shell is provided by tension on a spiral structure formed by stiffeners made of Kevlar or similar ultra-high modulus material (CBM).

 In addition, this problem is solved due to the fact that the device is equipped with a power device designed to change the volume of the cavity of the shell when performing a spiral structure in the form of an open torus.

 This problem is also solved due to the fact that in the method of creating a lifting force, according to the invention, the device according to claim 1 or 2 is used.

 In the inventive device, only one shell is used, there are no additional closed cavities for accommodating pressurized air, which in the prototype are designed to prevent collapse under the influence of atmospheric pressure.

 The ability to maintain a given shape and not lose it under the influence of air pressure in the external environment is provided through the use of stiffeners. At the same time, if necessary, the lifting force can vary due to changes in the volume of the shell, and due to changes in the amount of air in it. In both cases, the air density changes. Combining capabilities allows you to choose the best option for lifting.

 The invention is illustrated by drawings, where figure 1 presents a diagram of a lifting device; figure 2 - diagram of the specified device, taking into account the deflection under the influence of atmospheric pressure; figure 3 - scheme of compression of the ring; figure 4 - diagram of the force on the ring; figure 5 - the shape of the stiffeners in the form of an oval pipe; Fig.6 is a diagram of a device in the form of a torus: Fig.7 is a diagram of a device in the form of an open torus.

 We calculate the possibility of creating such a lifting device, a diagram of which is presented in figure 1.

 Let this device be a cylinder of length H, radius R. The ribs of this cylinder are made in the form of a spiral with the same radius R and pitch h. Then this device can be represented with fairly high accuracy as a composite device of N cylinders with the same radius R and length h, where N = N / h.

 Let for simplicity of calculations, R = h = 1 m, f = 0.1 m - the deflection of the shell under the influence of atmospheric pressure (see figure 2).

где Р₀ = 1 атм = 1 кг/см²
Тогда h = 104 см = 1 м. Таким образом, при такой оболочке ребра жесткости можно расположить еще шире, если прогиб f будет больше. Поверхностная плотность такого материала составляет ρ=140 г/м². Общая площадь цилиндра (без учета прогиба и без торцов, так как при достаточно большом количестве N ими можно пренебречь) будет составлять
S=4πR²=12,6 м²,
тогда масса оболочки будет М_{оболочки}=Sρ=1,8 кг.Assume that the stiffener is at a distance of 1/2 h from the edge, i.e., is located in the middle of the given cylinder. The shell of this device can be made of a duplex (double film) of polyethylene with a thickness of 0.02 mm and a polyester with a thickness of δ = 0.8 mm. The tensile strength of such a film is determined by a film of lavsan, which is equal to σ = 1700 kg / cm ² . Then for this design, the distance between the stiffeners should be

where P ₀ = 1 ATM = 1 kg / cm ²
Then h = 104 cm = 1 m. Thus, with such a shell, the stiffeners can be positioned even wider if the deflection f is greater. The surface density of such a material is ρ = 140 g / m ² . The total area of the cylinder (without taking into account the deflection and without ends, since with a sufficiently large number of N they can be neglected) will be
S = 4πR ² = 12.6 m ² ,
then the shell mass will be M _shell = Sρ = 1.8 kg.

The volume of this cylinder will be
V = πR ² h = 3.14 m ³ ,
then at γ _air = 1.3 kg / m ^{3 the} mass of displaced air will be
M ₀ = Vγ _air = 4.08 kg.
Then, with a shell mass of 1.8 kg, in order to create an equilibrium state, the stiffener, represented with sufficient accuracy in the form of a ring, must have a length L = 2πR = 6.28 m, a density per 1 m of length ρ ₁ = 0.363 kg / m and at h = 1 m and atmospheric pressure P ₀ = 1 atm = 1 kg / cm ^{2 to} have compressive strength
σ ₁ ≥100 kg / cm.
We calculate the stiffener. The ring on all sides in any section experiences only compression (see figure 3).

Следовательно, максимальное давление на сжатие кольца будет
N=PR, где Р=P₀h=100 кг/см² 100 см=10000 кг/см
Ребра жесткости, изготовленные в виде кольца с круглым сечением из полимерной пленки, армированной на эпоксидной смоле волокнами из кевлара (характеристики материала ρ= 1380 кг/м³, σ= 14000 кг/см, пусть Nсжатия ≥ 0,5Nрастяжения при потере устойчивости), должны иметь площадь сечения
S_сеч=10000/7000=1,43 см²
Тогда ребра жесткости имеют плотность на 1 м длины ρ₁ = 0,197 кг/м.
При изготовлении ребра жесткости в виде овальной трубы (см. фиг.5), где
r - больший радиус овала по центру стенки, a t - толщина стенки трубы, можно значительно повысить (до 40%) жесткостные параметры при той же массе ребер жесткости или значительно уменьшить массу ребер жесткости.Imagine that the ring is in equilibrium (see figure 4), then

Therefore, the maximum compression pressure of the ring will be
N = PR, where P = P ₀ h = 100 kg / cm ² 100 cm = 10000 kg / cm
Stiffening ribs made in the form of a ring with a circular cross section made of a polymer film reinforced with Kevlar fibers on epoxy resin (material characteristics ρ = 1380 kg / m ³ , σ = 14000 kg / cm, let N compression ≥ 0.5 N tensile with loss of stability), must have a cross-sectional area
S _section = _10000/7000 = 1.43 cm ²
Then the stiffeners have a density per 1 m of length ρ ₁ = 0.197 kg / m.
In the manufacture of stiffeners in the form of an oval pipe (see figure 5), where
r is the larger radius of the oval in the center of the wall, at is the pipe wall thickness, it is possible to significantly increase (up to 40%) stiffness parameters with the same mass of stiffeners or significantly reduce the mass of stiffeners.

The lifting force per one segment of the device, with a length and radius of 1 m, will be F = M ₀ -M _shell -M _ribs = 1 kg.

Thus, the possibility of creating a device having a lower weight than the weight of the air displaced by it, which is protected from collapse due to the action of atmospheric pressure by a rigid frame, has been proved. When the pressure inside the shell P _int > 0, the strength characteristics of the shell and stiffeners can be reduced, thereby reducing the weight of the entire device. The strength margin of 40% allows you to adjust the lifting force within the same limits by changing the volume of the device due to a change in the pitch between the spirals h.

 The device, made in the form of an airtight shell, stretched over a spiral design, has a fairly wide scope. Here are some examples of using this device.

 Example 1

 In places where the installation of towers for relaying radio signals (cellular radiotelephones, television, broadcasting, etc.) is impossible or expensive (swamps, permafrost, etc.), this device allows you to solve this problem. Having created the lifting force and lifting this device to the desired height, it can be held in place with a cable (or several cables). In addition, by connecting the ends of the device with each other, we get a torus. In the context of the device apparatus is shown in Fig.6.

 In this figure, the numbers denote: 1 - a flexible shell having a coating on the outside (upper) side that reflects the radio waves, and in the stretched state having the shape of a parabola; 2 - a closed volume isolated from the external environment, 3 - cables that hold the device in place and orienting it in a given direction; 4 - receiver (adder) of the radio signal; 5 - compressor evacuating air from the torus itself and from volume 2.

 When pumping air out of the torus, a lifting force is created sufficient to lift the entire apparatus to a height specified by the length of the cables. Using these cables, you can also set the necessary direction of the orientation of the torus in space (for example, to another relay station or to a space relay satellite). Pumping air from volume 2 gives the soft shell 1 the necessary rigidity, which turns it into a parabolic antenna.

 Example 2

 Using an aircraft made in the form of an airtight shell stretched over a spiral structure in the form of an open torus (Fig. 7) allows you to quickly change the lifting force. In this figure, the numbers denote: 6 - the ends of the airtight shell, stretched over a spiral structure; 7 - pilot's seat; 8 - fixture of the pilot's place to the open torus; 9 - power device proportionally increasing or decreasing the length of power cables 10.

 If the length of the power cables decreases, thereby increasing the internal volume of the torus, which means that the lifting force also increases due to the increase in the amount of air displaced by the torus, the apparatus rises. And vice versa, if the length of the cables increases, then under the influence of atmospheric pressure the volume of the torus decreases and, consequently, the lifting force decreases, the apparatus lowers. The magnitude of the lifting force in this case can quite quickly vary between 20-25%.

 Example 3

 This device is quite small in size can be used in the form of balloons, automatically changing the lifting force with the help of power cables depending on the purpose of the probe. On such a probe, it is possible to place almost any measuring and control equipment, and the duration of the probe’s flight is several times longer than the duration of the probes currently in use.

Claims (3)

1. A device for creating a lifting force containing a closed pneumatic stressed shell made with the possibility of changing the air density both by changing the volume of the shell cavity, and by changing the amount of air in the shell cavity, characterized in that the pneumatic tension of the shell is provided by tension on the spiral structure formed by the ribs stiffness from Kevlar. 2. The device according to claim 1, characterized in that it is equipped with a power device designed to change the volume of the cavity of the shell when performing a spiral structure in the form of an open torus. 3. A method of creating a lifting force, characterized in that the device according to claim 1 or 2 is used.

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