US3456903A

US3456903A - Airship

Info

Publication number: US3456903A
Application number: US629167A
Authority: US
Inventors: Hermann Ernst Robert Papst
Original assignee: Individual
Current assignee: Individual
Priority date: 1966-04-09
Filing date: 1967-04-07
Publication date: 1969-07-22
Anticipated expiration: 1986-07-22
Also published as: BE696793A; DE1481222B2; SE357523B; SE328193B; NL152804B; FI49947B; DK133186B; DE1481222A1; IL27731A; GB1191322A; JPS4886297A; SU558632A3; JPS4886298A; AT300581B; SE363072B; GB1191321A; AT294589B; SU520896A3; LU53360A1; CH475125A

Description

Julyzz,1969 H. E. R. PAPST l 3,456,903

` AIRsHIP Filed April 7, 1967 4 Sheets-Sheet 1 ZmMg//MM July 22,1969

Filed April v, 1967 4 Sheets-Sheet 5 H. E. R. PAPST AIRSHIP July 22, 1969 4 Sheets-Sheet 4 Filed April 7, 1967 FIG.1

FIGM

United States Patent O 3,456,903 AIRSHIP Hermann Ernst Robert Papst, Kark-Meier Strasse 1, St. Georgen, Black Forest, Germany Filed Apr. 7, 1967, Ser. No. 629,167 Claims priority, application Germany, Apr. 9, 1966, I 39,186; Dec. 24, 1966, P 41,101 Int. Cl. B64b 1/58, 1/06, 1/36 U.S. Cl. 244-30 21 Claims ABSTRACT OF THE DISCLOSURE An airship provided with a non-rigid double wall insulating envelope and utilizing water vapor and gas Ias a lift medium. The insulating agent used within the envelope is air which is blown between separated double walls of the envelope. The airship is also provided with bow and stern jets for propelling and steering the airship.

Brief description of the invention The invention concerns an airship and, more specically, an airship which operates with water vapor and gas as a lift medium in a ships hull and through a novel type of insulating envelope operating mainly with air as an insulating agent, as well as through a special development which can be utilized in such an advantageous manner that the transportation costs of such an airship for both freight and passengers will be considerably below the costs of traditional means of transportation, such as railroad, air and highway transportation. The invention makes such airships a generally practical means of transportation.

The airships that have been built in the past were filled, as a rule, with hydrogen or helium as a lift gas. The noncombustible helium, however, is very expensive and, therefore, makes the operation of airships as a mass means of transportation uneconomical; hydrogen, on the other hand, is so dangerous that its use in airships for passenger traic is no longer permitted because of past catastrophies.

As early as 1908, the proposal had been made to use superheated steam as a lift agent of airships. The use of superheated steam, however, had been proposed for rigid dirigible airships, since the assumption was made that only in rigid dirigibles could the insulating agent, consisting of down, be placed around the individual cellules. (German Patent 214,019.) Also the lift of water vapor was too small to carry the expensive multipartite frame construction of a rigid dirigible, consequently a plurality of gas bags were required to provide the additional necessary lift for the frame and insulating agent.

It is the purpose of this invention to create an airship which will satisfy the present day requirements made of transportation means with regard to safety, especially against the danger of re and explosion, as well as with regard to economy in production and operation. It is lalso an object of this invention to provide an airship suitable under present day conditions for the transportation of passengers and goods even yacross long distances and which is largely independent of landing places.

The invention comprises specifically a nonrigid airship constructed in a new manner, utilizing a new type of system for the lift, and also, above all, the construction of a new type of insulating envelope, a new type of propulsion system, a new type of construction of the keel frame or of the rigid operating and transportation spaces carried by the airship, as well as devices and the production process for the connection of several layers of the insulating envelope. It is also within the scope of the invention to provide the outside skin of the envelope with a nonabsorbent layer, in order to reduce air resistance and loading down through precipitation. Within the framework of the invention of a new usable airship operating with water vapor, there will also be means to enable the safe handling of the airship in all kinds of weather by quick and firm anchoring at landing places, especially on roofs of buildings.

The nonrigid airship has a big advantage as compared to the rigid dirigible in not needing an expensive, complicated construction for the support of the envelope. Instead of a plurality of gas bags, it will essentially get along with one large cellule for the water vapor, whereby the balancing air cells, preferably housed in the bow and the stern, are heated and carried along with it. A nonrigid airship also has the advantage that expensive docks are not required for docking the airship and that after blowing off the lift medium, the nonrigid envelope is rolled up or folded. The use of water vapor according to the invention is advantageous, not only because of the greatly changeable shares of cold or heated air in the balancing and trim cells in such nonrigid airships, but also especially, because during blowing of of the lift medium no considerable economic losses will occur, as is the case with such lifting mediums as helium or even hydrogen, which are diliicult to replace.

Only the combination according to the invention, in using water vapor and air as a lift medium in a nonrigid airship with an insulating envelope, makes possible the creation of an airship, which is economical, safe and reliable for the transportation of mass freight and passengers -across any desired distances. The high condensation heat of the water vapor of 330 kcal./m.3 gives a good thermal stability as against a pure gas illing. A further advantage of the vapor and air filled airship, according to the invention, consists in this, that the lift can be greatly altered, at little cost, to the specific requirements given through load and atmospheric conditions, by blowing in or condensing fairly large quantities of steam with a resulting change in the temperature of the special air lled trim cells. The change in temperature can also be aided by the subdivision of the envelope by heated insulating sheeting.

If, for example, a load is discharged, then first of all one would attempt to leave the gas and heat content of the airship unchanged and, instead of the load, take in a corresponding amount of ballast, preferably water. This will cost the least; the only cost will be for the operation of the pump.

If this is not possible, then one will iirst of all displace the warm air contained in `the bow and stern balancing cells with fresh air introduced into the cells through the blowers producing the gas cell pressure. If the airship only has about half the maximum load on board, then one will be able to compensate largely for the discharge of the load without any balancing through ballast by an exchange of warm for cold air.

For larger loads, it will iirst of all be necessary to produce more steam. The latter is then condensated up to about half the weight of the rest of the load that is remaining to be discharged after the exchange of air. The water that has been formed will balance out the lift of the remaining quantity of steam. Therefore, for the recreation of the bearing power for a new load, one -needs to evaporate this condensate again and one needs only to heat up the air in the trim cells.

For very large loads, one ills the envelope of the non` rigid airship with steam, except for a very small fraction of air in the trim cells. If one blows off this steam, into the atmosphere for some reason or other, up to the point of the necessary lift for the airship itself, then one will have to either load anew or produce on board a like quantity of water from steam instead of the weight of the load. This costs about DM 700.00 for 100 t. of load at DM 100.00 for 1 t. of heating oil or natural gas. This is the most expensive but, at the same time, also the quickest method for compensating for load.

The propulsion of the airship according to the invention takes place advantageously exactly in its axial direction by means of air currents produced in special blowers, which air currents are blown out through slotted rocket jets positioned in the bow as well as in the stern. The slotted rocket jet in the bow has been provided with guide means to deflect the expelled air current backwards, glidingly along the bow surface during normal flight. With that, a part of the propulsive energy is introduced directly into the flight counter-current and thus the gas shock pressure of it on the envelope is decreased. This will permit getting along with a lighter envelope for a certain required safety factor.

Beside the lift steam, one can advantageously also use a certain quantity of -a combustible gas producing a lift. This combustible gas, such as natural gas (methane) or hydrogen, is stored either in separate cells surrounded in a iireproof manner by noncombustible water vapor and/ or they are directly added to the water vapor. The gas which is added directly is added at the most in such a quantity that there is no danger of its igniting if the mixture somehow escapes into the air. The combustible lift producing gas that is consumed by the driving engines or the steam producers for the heat reserve of a motor at standstill, approximately equals the amount of heat value supplied. This method of operation will avoid changes in lift and allows, at the same time, a maximum measure of heat being carried along by the airship in its travel. Insofar as the natural gas which had been loaded is not consumed, it increases the loading capacity of the airship through the larger carrying capacity as compared to water vapor (plus 12% Removal of the light gas takes place directly from the special cells or else the gas can be separated from the water vapor by means of condensation of said water vapor.

Furthermore, in accordance with the invention, the nonrigid envelope of the airship can be secured to the keel frame containing all of the spaces for operation, for machines and for transportation, whereby said frame has been developed in such a manner, that when it settles down on the ground a sealing path is formed in a resilient manner between theI ground and its entire bottom surface or with the reinforced skeleton frame.

For securing the airship, according to the invention, on the ground, provision has been further made to provide the entire bottom side, or those portions of it which have been formed as suction cups, with suction fans, preferably with a driving blower, so that the airship will be sucked in with great force to the ground after setting down. Furthermore, it has also been proposed to provide the bottom side of the keel frame with pull magnet plates, which will produce, when the landing surfaces are studded with steel plates, an additional anchoring force that would augment the suction hold. One can produce with edgewise fiat rods made of iron and with ceramic, placed in-between said rods, grid-like permanent magnets. With about 200 kg. expenditure of weight, 50 t. of magnetic attraction per square meter is produced by such a magnet.

For example, an airship according to the invention, for the transportation of 75 t. of freight or about 400 passengers on seats, at a diameter of 53 m., a length of 170 m. is required. It has an air layer insulation of 0.3 m. thickness, which lets through 9 kcal. of heat per m.2h., at a 100 C. temperature difference. Its shape is about 'that of a spindle. Slotted rocket jets for propulsion and control are positioned at both ends. The attainable speed in the case f development as a freight airship will amount t o approximately 160 km./h. In the case of a flying speed of 70 km./h., the loss of heat by the lift media, vapor and air, through the insulating envelope, will be compensated fo'i by the exhaust heat of the engines.

According to the invention, if loads are to be discharged from the airship on nonprepared landing places, then first of all the lift is decreased by an exchange of warm air for cold air in the bow and stern cells. The intermediate walls in these cells, which can be inverted inside the outside envelope in the manner of a nightcap toward the steam-lift chamber, also have heat insulating double walls and are provided with tension members. Therefore, air can be blown between the intermediate double walls or can be sucked out of the walls, so that the passage of heat from the steam-lift chamber to the cells can be blocked or somewhat impeded when desired. The air temperature in the bow and stern trim cells can be changed independently of the vapor space on the basis of this principle. An exchange of cold for warm air requires only 1l kg. of heating oil or 16 cbm. of natural gas (100 C.) for the production of 1 t. of lift and this costs about DM 1.00 to DM 1.50.

If all warm air in the bow and stern cells is blown out and displaced by fresh air, one can either let out water vapor in the case of a bigger change of the load or one can condense said water vapor more, and the latter is most advantageously accomplished when one blows the fresh air through the bow and the stern cells for sometime and thus carries off the required quantity of steam heat. For this purpose, the intermediate wall is -ventilated so that it will have an at least 100 times better capacity for conducting heat as compared to the insulating effect. The ballast water that is formed consumes approximately the lift of an equal quantity of steam. For new transportation tasks it will then be necessary to use approximately 35 g. of fuel oil or about 50 m.3 of natural gas at 100 C. for the production of steam per l t. of lifting force. The lifting cost for a load that is to be taken up therefore amounts to only about DM 3.50 per 1000 kg. If this airship hovers for 1 hour without its engines running, then the lift will be maintained through combustion of 25 kg. of fuel oil or 35 m.3 of natural gas at 100?v C. In the case of this value, let us figure with an effective heat emission surface of about 20,000 qm. Every mi'nute of stopping time would therefore cost about DM 0.05.

The outside surfaces of the envelope of the new airship are completely smooth in order to have only a small surface resistance. Any constructional protrusions for steering or for the motors have been avoided. The required useful spaces and the engine installation are housed in' their entirety in the keel skeleton, whereby this has been calculated statistically in such a manner that even with a full load, it can still rest with merely two points atits two ends on the landing place.

Advantageously, the keel skeleton consists of a strong lattice construction, preferably made of aluminum extrusion pipes, in which the propellent is housed preferably in foldable containers protected in a iireproof manner and subdivided.

During the operation of the airship, the loss of heat 1s so small as a result of the insulating envelope according to the invention, that a steam airship of the above-mentioned measurements can hover for 200 days with a payload. At km./h., a liying distance of more than 100,000 km. Acan be achieved if in the blister in the water vapor 75,000 m3 of natural gas (100 C.), as well as 53 t. of oil have been taken along, which would cost about DM 11,000.00. The simultaneous use of gas and oil does not influence the lift conditions of the airship. The lifting force, through steam and warm air, available for the payload and the constructional elements of the airship, at the same time amounts to about ll2 t. The envelope in a design for four-fold safety at a maximum dynamic pres: sure of 1,50 mm., uses up 32 t which is suicient forabout 200 km. speed. The keel skeleton, the engines, improvements as well as propulsion according to an estimated calculation require 45 t. Therefore, 30 t. of payload and 5 t. for reserve will be left over.

For shorter distances up to 2000 km., at 100 km./h. and 1000 H-P of power output, the payload for a freight ship will be around 50 t. higher.

Because of the omission of steering surfaces and the avoidance of a hitherto customary eccentric drive system which has been replaced by an axial drive positioned simultaneously at the bow and the stern, the new steam airship can be developed with a diameter to length ratio of about 1:2 to 1:3, Which is much more favorable for propulsive resistance. In this way, the ratio of capacity to surface has been considerably improved. Rigid airships that were constructed had a ratio of D:L=l:5 and more. The portion of the entire resistance from pure drag amounted to while the resistance of protruding constructional elements amounted to 28% and the surface resistance amounted to 57%.

Only through omission of the tail unit and of the outlying motor nacelles as Well as through the stabilization of the drive by means of the driving and steering system through the jet propulsion drive, on bow and stern of the new airship, has the shorter shape become usable.

As a result of the reduction in surface area, the heat losses will be correspondingly lowered. As a result of that, there is no longer any necessity to subdivide the lift space occupied by steam and other lifting gases. It has been found that it is simpler and more economical to utilize the expenditure required for the subdivision of the cells for an increase in the strength of the envelope. The outside wall of the envelope, in the case of the type of construction provided, can be light and can be developed strong enough, so that a higher barometric pressure of the lifting gas, occurring in the case of a slanting position of the airship, can be absorbed with maximum safety.

Airships that were built hitherto also had the disadvantage that they could execute control movements with their tail unit, only at a proper speed which also produced an aerodynamic lifting force. The axial drive according to the invention with a flow around the hull of the ship will permit one to achieve control movements even at a standstill of the ship when one of the drives, either on the bow or on the stern, is reversed in its directional action.

The heat insulating outside envelope of the body of the ship according to the invention, consists of double walls which are connected with many continuous bands, said bands subdividing the space between the double wall. The bands are in tension and are held at a distance by the pressure of a gas lled in-between the double wall, said gas being preferably air, which pressure surpasses by at least the barometric degree of pressure, the pressure of the lifting gas acting upon Ithe inside part of the wall serving as a cellule. Therefore, the double Walls of the body of the airship have the heat insulating distance at every place. Convection movements of the gas are prevented by the tension bands. The distance of the cross bands is in the order of magnitude of centimeters, for example 5 cm., while the distance of the double walls from one another amounts to a multiple of that, for example 30 cm. For the reduction of the radiation of heat, the cross bands are covered preferably on their inside with a heat reecting metal layer. Preferably, an evaporated lm consisting of aluminum is applied, which needs only to be thin and which is economically usable for even several hundred thousand square meters.

For maintenance of the distance of the Walls of the envelope from one another across the entire surface, the gas pressure between the walls of the envelope must be higher by at least the barometric degree of pressure of the lift gas than the pressure of said lift gas. According to the invention, this difference in pressure is produced advantageously by means of a continuously running auxiliary blower, which sucks up air from the trim cells and, as a result of that, assures the required difference in pressure without complicated controls. The end cells of air are lled by other blowers, preferably by the blowers for the production of jet propulsion air. The pressure in the lift gas, therefore, is less per se than the ,required counterpressure for the outside dynamic pressure, because the pressures in the gas chamber and in the intermediate Wall are superposed or inlluence each other. This is accomplished by the effective connection between the outside double wall of the envelope by means of tension bands, said bands being evenly distributed, because they have to be tightened in order to maintain the distance. This can be utilized to make the gas cell pressure, exerted upon the lift gas in the case of a nonrigid airship, las low as possible, in order not to decrease the lift values. Even with very thin foils, used as surface-like tension bands, one will easily achieve a -fold safety for them and for the adhesive and welded connections.

For the purpose of protecting the envelope against sun and weather, the actual carrying layer is covered on all sides with a aluminum foil which is impervious to moisture and light, and which in turn is protected against corrosion and the occurrence of sudden leaks by being covered with -a polyvinylidene fluoride foil, which is resistant for a long time with regard to sunlight and weather. Such a foil, which has been tested, is available on the market under the trade name Tedlan However, other foils too can be used which have this characteristic and which on top of that are nonabsorbent or, to express it in other words, water repellent. With such a nonabsorbent layer, atmospheric precipitation will not make the envelope wet but will run olf or will be blown off by the ow of the air about the body. As a result of that, a weighing down of the airship will be prevented.

According to the invention, the inside of the envelope of the double wall facing the water vapor is also covered with an aluminum foil and with a polyvinylidene uoride layer. First of all, a chemical attack of the water vapor on the tissue of the inside wall and the foils sealing it will be prevented; furthermore, the condensate will run ol immediately in very small droplets, so that the inside of the envelope too, will not be weighed down by water. The achievable payload therefore, will not be reduced.

For complete insulation, the prevention of a heat loss due to radiation is still necessary. Zig-zag shaped strips may be used which are positioned between the connecting bands and are made of a very thin synthetic material foil having an evaporated aluminum layer. With the use of such strips, the loss of heat, which already is very small, will still be cut in half. However, the strips may be omitted in airships having a very good engine performance and increased exhaust heat, because there will be suicient exhaust heat at ones disposal to compensate for the heat loss due to the radiation.

Furthermore, in accordance with the invention, the proposal is made to select as the nonabsorbent material on the aluminum foil, a substance that permits the aluminum foil to be heated in a high vacuum beyond the critical temperature of the water vapor and air, the substance in that case not yet decomposinig but melting tightly onto the foil without any remnants of water vapor being enclosed'. Such a layer, because of low surface tension, has no inclination any longer to bind a skin of water vapor from the atmosphere, as do all other materials. It is suspected that the particles of the boundary layer adhering close to the wall are held rmly on this absorbed water vapor skin, on which the known phenomena of flow will result during the tlow around bodies.

If, therefore, one should be successful in eliminating the Water vapor skin, then one could expect that no adhesive boundary layer would exist lany longer but instead gliding boundary layers would exist. As a result of that, the loss of low would be largely reduced.

Another statement of Itiuid physics makes the fluid friction disappear whenever the bodies are smooth up to 10-8 cn., i.e., electron-optically. Through the melting process in the high vacuum which has been provided, with the simultaneous elimination of an adhesive possibility for the water vapor skin, one must also expect that the surface of such a fused layer is also smooth electron-optically.

It is proposed to use such aluminum foil or foils or other metal with layers applied in a high vacuum for the achievement of gliding of the tiow boundary layer (for the purpose of reducing the surface resistance) in the case of gases and liuids on or in watercraft, land vehicles, aircraft, machines and tools. The individual walls, according to the invention, consist preferably of high strength fibers, for example, of polyterephthalic acid ester, with crossediilaments lying one beside the other, which have been woven in accordance with known processes, or which cross each other lying in parallel one beside the other. In the case of tbe latter arrangement, the connection of the filaments is brought about through a coating on an intermediate layer. According to the invention, the outsides of the fabrics or of the crossing filaments having the intermediate layer are connected to tight, shift-proof 4surfaces by means of a solid foil, preferably made from the same high strength synthetic material, through an adhesive agent or through fusing by means of a welding process, for example, by means of ultrasonics.

In the case of an arship, the strength of the fiber or the number of fibers` in the main stress direction of the fabric is made, preferably, twice as strong as in the longitudinal direction of the fabric of the envelope. In this manner, an exceedingly light, highly constant envelope having great strength and safety is provided for the nonrigid arship.

The tiber web or cross web, sealed in the manner described, is additionally, and according to the invention, saturated at its edge through connection with an incoming liquid mass of mastic, penetrating the web, which enters by sections even in the cross direction, In this manner, fields that have been closed in an air-tight manner, develop between the cover foils and the periphery of the `sealing tracks, which prevents moisture from spreading lthey are gradually reduced in strength. The inner and outer cover of this web of the double walls, therefore, protect the envelope of the arship from such a seasoning, since a metal layer, as is well known, is impermeable to water vapor and the bottom layer protecting the metal in addition, will allow, like all highly molecular synthetic substances, the water vapor to dilfuse.

. The connection of the individual sectors of the envelope made from lengths of fabric is accomplished through overlapping adhering, whereby the lengths of fabric cover each other up and also cover the synthetic foils protecting the fabric. The adhesive connections are carried out ad- `vantageously with a two-component adhesive or a Contact occurs in the layer of air between the double walls.

Nevertheless, the envelope must be stable against a temperature corresponding to the water vapor, because one has it within ones power through letting out the separating layer of gas between the double walls, to make those two labut against each other and to bring about a quick condensation of the water vapor, for exampleZ in. order to discharge a load or in order to stop the a1rsh1p and to store it.

The temperature of the water vapor can be reduced through admixture of a gas. According to known laws, the water vapor will then have acondensation temperature which corresponds to its partial pressure in the gas mixture. Preferably methane is mixed for this purpose with the water vapor, because this gas will increase the lift. Hydrogen can also be used as an additive, since it is not combustible if there is only a small portion of it in the water vapor.

In the arship according to the invention, one could use a superheated water vapor, since the foils and the materials of the fabric of the inside wall would be able to withstand that because of the little stress put upon them. However, when superheated water vapor is used, one will lose the advantage of having the condensation temperature of the water vapor, the saturated steam temperature, as the highest temperature at all place, instead the temperature would be higher so that the safety of certain spots of the envelope against overheating could only be achieved with complicated measures. Unfortunately, there is no other agent but water vapor which, at the same time, must be taken into consideration as a lifting gas and which has a higher evaporation temperature.

The use of saturated steam, that is to say, the reserve of steam being heated only a little beyond the boiling point, which can be easily achieved by adiabatic expansion, will achieve, therefore, the greatest degree of operational safety which is imaginable for an arship using warm gas for lifting force.

Additional advantages and areas of application of the arship according to the invention will become clear from the subsequent description taken in combination with the accompanying drawings in which:

FIGURE 1 shows the arship according to the invention with possible installation in the envelope;

FIGURE 2 shows the arship according to the invention in the shape of a spindle and with a ratio of diameter/ length of 1/3;

FIGURE 3 shows the arship according to the invention with an aspect ratio of 1/5;

FIGURE 4 shows a front view of the arship according to thel invention;

FIGURE 5 is a section through the double walled insulating envelope of the arship according to the invention;

FIGURE 6 is a section through the most extreme bow part of the arship according to the invention;

p FIGURE 7 shows a section through the outermost stern part of the arship according to the invention;

FIGURE 8 shows a section through the keel frame of the arship according to the invention with the envelope folded up;

FIGURE 9 shows a design of the arship according to the invention with a separate cell for the combustible gas and with end walls that can be turned inside out;

FIGURES 10, l1 and 12 show a device for application of a layer of synthetic material on a metal layer.

Detailed description of the invention According to FIGURE 1, the arship according to the invention, consists of a keel frame 1 and an envelope 2. The stern or the bow jets have been designated by 3 and 4. Inside the envelope of the arship, there is a supporting frame 5, to which stretching ropes 6 can be attached, which are capable of guiding the forces from the upper sideV of the envelope to the keel frame. If need be, the envelope 2 can be subdivided by transverse walls 30.

FIGURE 2 shows the arship according to the invention in the shape of a spindle with a ratio D:L=1:3, which results in favorable air-resistance values and in a favorable surface volume ratio.

FIG. 3 shows a shape of the arship, according to the invention, for achieving higher speeds with an aspect ratio of 1 to 5.

FIGURE 4 shows a front view of the airship according to the invention, whereby one can recognize that the envelope 2 with keel frame 1 is attached to longitudinal bands 31. The nonrigid envelope 2 itself, as can be seen in the drawing, has been entirely closed within the area of the keel frame.

During operation of the airship, the distance between the walls of the envelope is maintained by gas pressure. According to the invention, the gas pressure is produced by means of a continuously running auxiliary blower (schematically represented by box 40 in FIGURE 9) which sucks up air from

trim cells

28 and 29 through intake lines 42, 42', and exhausts air into the space `between the walls of the envelope through outlet line 44.

FIGURE 5, furthermore, shows a section through the double walled insulating envelope of the airship, according to the invention. As can be seen, the following sequence of layers from the inside to the outside of the envelope 2 has been provided: after the steam located inside the airship, there follows a non-moistening, that iS to say a nonabsorbent layer 7 of synthetic material, which 'preferably consists of polytetrafluoroethylene or polyvinylidene uoride. However, one can also use other synthetic substances with the same effect. This nonabsorbent layer of synthetic material has been applied to a metal foil 8 which is steam resistance and which consists preferably of aluminum. The two layers may be connected with one another by means of the specially described temperature application process under a vacuum or a protective gas. A binder layer 9 follows the metal foil 8, which binder layer consists of a commercial binder of synthetic substances and Vwhich is applied as a lacquer. With the help of this binder layer, the metal foil 8 will be connected with the fabric layer 10 of synthetic material.

The fabric made of synthetic material consists perferably of polyester which is temperature resistant beyond 100 C., however the possibility also exists to use instead of fabric, an arrangement of the threads as a lleece, in the form of adjoining parallel and crossing threads which can be bonded with one aonther. In order to absorb different tensions in the longitudinal and in the peripheral directions of the envelope, one can select, perferably, the ratio of warp/weft thread in such a manner-for example, 2:1-that the stress upon the individual threads of the fabric will be equalized. Furthermore, in order to prevent a bracing of the fabric in a diagonal direction, it is contemplated that in accordance with the invention, the bearing layer of fabric itself could be covered on one or both sides with a thin foil of the same material and that the foil could be broken into fields that are sealed in themselves, through strip shaped penetrating impregnation. With strip shaped penetrating impregnation, the foil is bonded with the fabric at least at each impregnated strip. According to the invention, continuous bands 11 follow the fabric layer 10a, b, c. The bands 11 likewise consist of a fabric made of synthetic material or of foils, and, to be sure, are made preferably of polyester. The bands 11, furthermore, are steamed with an aluminum layer 12 against heat radiation. They are welded together or bonded each time with the inside layer of a foil consisting of a synthetic fabric and with the outside layer 13a, b, c of a foil consisting of a synthetic fabric. In the U-shaped space of the transverse bands 11, surface sectors of a thin folded synthetic material foil 14 may also be provided. This foil 14 has preferably been covered by way of vapor deposit with aluminum or some noble metal. The foils 14 prevent heat radiation between the two layers of fabric 10a, b, c and 13a, b, c, and they prevent, at the same time, convection of the air located in between them.

The outside fabric layer 13 is followed in the same manner as the inside fabric layer 10 by a bonding layer 15, then there follows a water vapor resistant metal foil 16 and a nonabsorbent layer 17. According to the invention, the outside nonabsorbent layer 17 prevents rain, snow and dew from adhering to the airship, whereby the moisture runs otf the layer so that no additional loading of the airship will occur through surface moisture.

The layers described above and according to the invention, have the following dimensions, which should be considered as approximate values: the inside nonabsorbent layer 7 has a thickness of 25p, the inside metal foil 8 has a thickness of 11n, the bonding layer 9, which is present in the form of lacquer, has a weight of 4 g./m.2, the inside fabric layer has preferably a thickness of 0.15-1 mm., while 'the transverse bands 11 have a thickness of 5-25/t, and the metal layer 12, which was steamed on, has an approximate hickness of 0.1;t. The outside foil and fabric layer 13a, b, c is the `bearing layer of the entire envelope. Its thickness amounts to about 0.3 to 2 mm. The bonding layer of lacquer 15 has an approximate thickness of 4p, the outside metal foil 16 has a thickness of 11p., while the outside nonabsorbent layer 17 is 25, thick.

The double-walled insulating envelope according to the invention, at a temperature difference of C. for a wall distance of 30 cm. and at a distance of the cross bands of 5 cm., has a loss of heat of less than 17 kcal./m.2h; and in the case of a wall distance of 30 cm. with folding foils 14, the loss of heat amounts to even less than 10 kcal./m.2h.

FIGURE 6 shows, furthermore, a section through the outermost bow part of the airship according to the invention. The compressed air, produced preferably by diesel engines and propellers or blowers (the engines and propellers `or blowers being schematically represented by boxes 46) driven by said engines and located in the keel frame, is supplied to the bow jet via an air supply pipe 18, which is also formed of fabric-type materials. The air is distributed in slotted rocket jets with a medium jet body 20 and exits from the inside of the deecting screen 19 alongside the body of the bow. In the inner space of the jet body 20, there may be advantageously an observer or helmsman. The deflecting screen 19 may be adjusted hydraulically by conventional controls schematically represented by box 48 and hydraulic cylinders 50 which interconnect screen 19 with envelope 2 whereby the distance from the edge of the bow and may be adjusted laterally, and thus the airship may be steered. Advantageously, the screen should be foldable, so that the bow jet will blow out a jet counter to the normal direction of travel. In this manner, it will be possible not only to propel the airship according to the invention by means of the bow jet, as in the case of the normal position of the deflecting screen, but also to brake the airship with a folded up deecting screen. Lateral deflection of the compressed air takes place by means of a shift of the jet body 20 from its center position to one side of the edge of the slotted rocket jet. The overwhelming escape of air from one side to the bow nozzle produces forces, deviating from the line of the axis, which can be utilized for steering.

Through the central backward flowing off of the compressed driving air, the dynamic pressure on the bow part of the airship is, at the same time, reduced considerably, so that the necessary gas cell pressure becomes lower.

FIGURE 7 shows a section through the outermost stern part of the airship according to the invention. The air supply to the stern is accomplished again through an air supply tube 21, just as in the case of the bow. Corresponding in manner to the bow jet, the compressed air itself is produced in the keel frame. The slotted rocket jet is again formed through a central jet body 22, which again is adjustable axially and radially to all sides from its middle position by hydraulic cylinders 52 interconnecting the jet body 22 with envelope 2. By means of jet deecting surfaces that can be put forth from the jet body 22, it is possible to further deflect the stern jet. The jet body 22 can also be developed just like the bow body 19 as an observation post.

FIGURE 8 shows a section through the keel frame 1 of the airship according to the invention with a folded up envelope 2. The keel frame4 1 is fashioned of four longitudinally-running extruded sections of lig-ht metal pipes 23, which have large diameters. Therefore, it will be possible to store propellants and other operating agents in the light metal pipes 23, which are subdivided into cells, in a fireproof manner and shielded from the inside space of the keel frame. The four pipes 23 are connected with one another either through longitudinal and transverse walls or through diagonal trussings. This keel frame can be dimensioned to have a small weight evenly distributed for support at any two places, just as in the case of oceangoing ships. It can then land on any desired bearing sur face. The upper side of the keel frame can be provided with sturdy cantilever walls 25, which, after blowing olf the lifting agent, permit the envelope to be folded together. With this process, a separate airship shed becomes superfluous.

FIGURE 8, furthermore, shows the development of the keel frame 22 with suction plates 32, which are attached either separately by themselves below the keel frame, or else the entire bottom surface of the keel frame 1 is developed as a suction plate. On the sides of the suction plates or the sides of the keel frame 1, tire elements 24, preferably of a very strongly sealed fabric of synthetic material, have been attached. If the blower on the keel frame sucks away air, then a partial vacuum will be created below the plate of the keel frame. This partial vacuum will then hold the keel frame with the airship with great force on the ground. Because the tire 24 is sealed at the edge of the keel frame 1 or the suction plate 32, the sucking in can also take place on lawns, sand planes and similar places. For sucking in air, one can also use the regular driving blowers. Additional equipment to produce a partial vacuum will then be unnecessary.

FIGURE 9 shows another design of the airship according to the invention in which combustible gas is provided in a special cel1`33 located within and surrounded by noncombustible gas. The cell 33 for the combustible gas 15 is arranged in the middle of the airship. The cell walls 26 consist likewise of a synthetic fabric sealed with a metal foil against water vapor. The water vapor surrounding the cell 33 protects the combustible gas against the possibility of ignition.

The

walls

27 and 28 can be turned inside out, and separate the steam space from the air spaces. When air is blown between the double walls of

wall

27 or 28, the wall insulates the steam space from the respective bow or stern cell. However, when no air is blown between the double walls, the

walls

27 and 28 no longer insulate the steam space from the bow andstern cells. Thus, the air in the bow and in the

stern cells

28, 29 can be heated quickly or can also be blown through, by means of fresh air, independently of the steam space. Usually, the air in the bow and stern part is hot and therefore contributes considerably to the lift of the airship. If the lifting force of the airship is to be decreased, then the warm air is replaced by cold air through the blower. Inversely, an increased lift may be obtained through the fact that the air in the bow and stern parts is heated, because of the freely running blower 19, a superpressure will be prevented.

FIGURE 9, moreover, shows in a dotted line the separating walls 27 turned inside out. In this state, the airship contains the most air and the least steam. The lifting force is the smallest.

Another possibility of storing the combustible gas without any danger consists in admixing the gas with the steam. At the same time, the admixing ratio should be selected in such a manner that an ignition of the gas within the steam is impossible. To obtain the gas for consumption, a part of the steam-gas mixture is drawn off and cooled, so that the steam condenses and the gas is left over. The water obtained in this manner again is evaporated by the exhaust heat of the driving engines and is returned to the steam space. Suitably, the consumption of the gas and the consumption of liquid or solid propellants or similar things is accomplished in such a manner that the reduced lifting force, on the basis of gas consumption is balanced by a steady decrease in the necessary lifting force.

FIGURE l0 shows an arrangement for applying, on a metal foil, a layer of a synthetic substance that does not adsorb layers of water vapor. A roll of aluminum foil in a vacuum is drawn through the annealing furnace, represented by two plates at about 400 C., said aluminum foil being wound up by the right-hand winding roller. The fluorine resin plate has been lifted off.

FIGURE 11 shows a further step of the process according to the invention. The left winding roll is turned back, while the bloc-k of resin is pressed against the heated roll (above on the right-hand side). The resin will melt between the heating plates onto the foil in the vacuum. The foil is then wound back again.

FIGURE 12 shows a further step whereby a neutral gas, free of water vapor and of high pressure, for example, argon of 16 atm., is allowed to enter the boiler. The iluorine resin layer ,applied is molten at a higher tempera ture at the above-mentioned gas pressure without decomposition.

In view of the properties of the synthetic material, the airship according to the invention will advantageously be operated only with saturated steam. In this case, the advantage of saturated steam lies in the stability of the wall temperature of the envelope, because the condensation temperature in the nonrigid envelope is equally high everywhere. The disadvantage in the condensation of the saturated steam on the inside surface of the nonrigid envelope will be eliminated through the non-absorbent layer.

The water condensing along the wall runs off and is then pumped away (pump 54, intake lines 56 and discharge lines 58 schematically represented in FIGURE 8), heated by means of the exhaust gas heat of the driving motors 46 with exhaust gases passing through heating elements schematically represented heating element 60, and is returned again to the steam space. Superheated steam it is true, can also be used, but it requires special regulating installations.

As described the airship is driven by ordinary engines, such as diesel engines. Still the fact should not be excluded that other driving means, such as gas turbines, atomic reactors, etc., can be used. Furthermore, if these driving agents do not liberate sufficient exhaust heat, additional direct heating of the steam could be accomplished. Such a direct heating of the steam is also necessary to keep the airship hovering in the atmosphere without operation of the driving engines and also for the purpose of filling it prior to its start. Since the additional aggregates or the additional possibilities of use are clear to the expert, and no additional inventive process is required for their use, any further description of these is unnecessary here.

The coating of the outermost metal skin with a moistening, therefore nonabsorbent layer of synthetic material, has an additional advantage in the fact that through this, the boundary layer can, under certain circumstances, be considerably influenced and the friction resistance of the airship, which absorbs a considerable portion of the driving force, can be greatly reduced. Because of this surface, the air, so to speak, will glide past the airship without the formation of a boundary layer.

As can be seen in the foregoing description, which is not intended as limiting in any way, but which is merely to give a single design by way of example of a series of advantageous designs following the principle of the invention, the airship according to the invention is uniquely suitable for the safe mass transportation of passengers and freight.

The safety factor is to be found especially in the fact that even in the case of a very unlikely occurrence of large leaks in square meter areas, escape of the large volume of steam takes place so slowly that a safe landing of the airship Vwould still be possible.

While the preferred form of the invention has been shown and described, it is to be understood that all suitable modifications and equivalents may be resorted to which fall within the scope of the invention.

What I claim is:

1. Motor driven, maneuverable, non-rigid dirigible with a double wall envelope around the volume of lifting gas, said double Wall being air or gas filled to separate inner and outer walls of said double wall, intermediate elements and surface sectors extending between said inner and outer walls for decreasing heat convection and radiation between said inner and outer walls, character' ized in that:

said lifting gas comprising an essential portion of steam,

which, close to said envelope has saturated steam conditions;

said intermediate elements are tensile connectors se cured to and interconnecting said inner and said outer walls radially, said intermediate elements being collapsible and spaced a short distance in relation to one another; and

said surface sectors are formed of thin strips of collapsible foil which reiiect the heat and which are spaced close to one another for a zigzag configuration between said inner and outer walls and are secured to said inner and outer walls.

2. The non-rigid dirigible according to claim 1 wherein -inside said envelope air filled stabilization cells are provided, said stabilization cells having air or gas filled double walls with tensile connectors and zigzag-shaped heat reflecting strips of foil which extend between and are secured to said walls of said stabilization cells.

3. The non-rigid dirigible according to claim 1 characterized in that said heat reflecting strips of foil are covered with a thin metal layer.

4. The non-rigid dirigible according to claim 3 characterized in that the said thin metal layer covering each of said strips of foil comprises aluminum.

5. The non-rigid dirigible according to claim 3 characterized in that the said thin metal layer covering each of strips of foil comprises a noble metal.

6. The non-rigid dirigible according to claim 1 characterized in that the spacing between said inner and outer walls-of said double wall envelope is greater than the spacing between adjacent tensile connectors.

7. The non-rigid dirigible according to claim 1 characteribed in that said inner and outer walls of said double wall envelope each have thin metallic reflecting layers to retard heat radiation.

8. The non-rigid dirigible according to claim 7 characterized in that said thin metallic reflecting layers of said inner and outer walls of said double wall envelope are coated with a non-absorbent cover layer to prevent accumulation of water on said envelope.

9. The non-rigid dirigible according to claim 8 characterized in that said non-absorbent layers comprise polytetraliuoroethylene.

10. The non-rigid dirigible according to claim 1 characterized in that said inner and outer walls of said double wall envelope each comprise a layer of fabric made of synthetic fibers, veach of said layers being covered at least on one side with a thin foil.

11. The non-rigid dirigible according to claim 10 characterized in that said layer of fabric has differing tensile strengths in the longitudinal and peripheral directions of the envelope with the strength in one direction being twice as great as the strength in the other direction.

12. The non-rigid dirigible according to claim 11 characterized in that the ratio of warp threads to weft threads is at least 2:1 for the purpose of absorbing different tensions in the longitudinal and peripheral directions of said envelope.

13. The non-rigid dirigible according to claim 1 characterized in that the air or gas between the inner and outer walls of said double wall envelope has a pressure at least as great as the pressure of the lifting medium within said envelope.

14. The non-rigid dirigible according to claim 13 characterized in that the gas or air in the interval between said inner and outer walls of said double wall envelope is pressurized by means of a blower means.

15. The non-rigid dirigible according to claim 1 characterized in that said lifting gas contains a portion of a combustible operating gas in addition to said steam with the concentration of said combustible operating gas being below the concentration required for ignition.

16. The non-rigid dirigible according to claim 15 characterized in that means is provided for separating said combustible operating gas from said lifting gas for consumption of said combustible operating gas in the operation of said dirigible.

17. The non-rigid dirigible according to claim 1 wherebow and stern jet means are carried by said double wall envelope along the longitudinal axis of said envelope;

a rigid keel frame is carried on the underside of said envelope, said keel frame housing blower means, said blower means interconnected to said bow and stern jet means by supply pipe means;

said bow jet means comprising a first body adjustably secured to said envelope and having a surface configuration complementary to the surface of said envelope adjacent said first body and forming with said envelope a first annular opening for discharging compressed air to propel and steer said dirigible, means for adjusting said first body both radially and axially with respect to the longitudinal axis of said envelope to regulate the size and configuration of said first annular opening for effecting the propulsion and steering of said dirigible; and

said stern jet means comprising a second body adjustably secured to said envelope and having a surface configuration complementary to the surface of said envelope adjacent said second body and forming with said envelope'a second annular opening for discharging compressed air to propel and steer said dirigible, means for adjusting said second body both radially and axially with respect to the longitudinal axis of said envelope to regulate the size and configuration of said second annular opening for effecting the propulsion and steering of said dirigible.

18. The non-rigid dirigible according to claim 17 characterized in that said second body is conical in configuration and is mounted within and protrudes from a cavity formed in said envelope.

19. The non-rigid dirigible according to claim 17 characterized in that said first body has a detiecting screen in the form of a hollow, truncated cone which tapers toward the lbow of said envelope, said defiecting screen co-operating with said envelope to form an annular gap for expelling compressed air in a generally rearward direction.

20. The non-rigid dirigible according to claim 17 characterized in that the rigid keel frame has a large essentially flat floor means which extends substantially the length of the envelope, the underside of said floor means having an elastic seal which encircles at least a part of the underside of said fioor means and suction means carried in said keel frame and interconnected to the underside of said floor means to create a partial vacuum between a landing surface and the underside of said iioor means.

21. The non-rigid dirigible according to claim 20 characterized in that the blower means within said keel frame for supplying compressed air to said bow and stern jet means also serves as said suction means.

References Cited UNITED FOREIGN PATENTS 5 MILTON BUCHLER, Primary Examiner STATES PATENTS IGmbel 244 125 RICHARD A. DORNON, Assistant EXaIIlIlel' Donnell et al. 244-30 Trey 24 30 Us. c1. XR.

Desmarteau 244-30 10 244-52, 61, 99, 126, 12S