US1763835A - Airship - Google Patents

Description

R. H. UPSON- June 17, 1930.

AIRSHIP Filed Jan. 24, 1924 5 Sheets$heet m m m m RHLF'HLJPsc/v. M M

June 17, 1930.

R. H. UPSON AIRSHIP Filed Jan. 24, 1924 5 Sheets-Sheet FIGJI.

INVENTOR.

N WW .E SW H w H A m Y B June 17, 1930. R. H. UPSON AIRSHIP 7 Filed Jan. 24, 1924 FIE-.11.

5 SheetsSheet 3 INVENTOR. R HLFH H. L/F'E'UN June 17, 1930. UPSON 1,763,835

AIRSHIP Filed Jan. 24, 1924' 5 Sheets-Sheet 4 INVEN TOR. RF7L/=H I-LL/F'SUN 414$ ATTORNEY. 3

R. H. UPSON Julie 17, 1930.

AIRSHIP Filed Jan. 24,vl'924 S'Sheets-Sheet 5.

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Patented June 17, 1930 UNITE STATES PATENT OFFICE RALPH H. 'U'PSON, OF BIRMINGHAM, MICHIGAN, ASSIGIVOR TO AIRCRAFT DEVELOP- MEET CORPORATION, 015 DETROIT, MICHIGAN, A CORPORATION OF MICHIGAN AIRSHIP Application filed January 24, 1924. Serial No. 688,115.

These inventions relate to airships. The objects include the production of airships, as the term is now understood, having many advantages over any design or construction heretofore known. The advantages and resultsmay be thus stated: provision of airships of greater air-worthiness, the reduction of fire hazard, protection against lightning, more complete equalization of temperature, economy of buoyant gas and ballast, improved strength to resist stresses due to static and aerodynamic loads, in general to reduce weight of structure and to attain any or all of these advantages in a rigid ship, and in a way that involves practical method of construction of parts, assembly and erection, and withal more advantageous accommodation for supplies as well as goods or passenger loads, and also a structural unity of ship particularly well adapted for mooring as well as for flight, maneuvering or housing.

These various advantages, or any of them, result from a design and construction of airship,in' which a single metal envelope, with the other features of construction, provides a rigid ship of great structural efficiency, and which structurally carries the static loads when inflated, and which meets all the requirements of increased aerodynamic forces when in flight.

I The subject-matter is'related to my work in the development of rigid airships and bears upon certain disclosures in my pending'application Serial No. 558,541 filed May 1, 1922, with refinements with respect to certain of the features therein disclosed, as well as additional matter developed in my research, all bearing particularly upon rigid airships. While certain of the subjectmatter applies to rigid airships of any type, I will describe the inventions more particularly in one embodiment in which the construction is of the so-called metalclad type. The constructionof the particular embodiment shown in the accompanying drawings involves a single metallic sheathing forming the skin of the ship as well as the envelope for the buoyant gas. The en velope 'thus takes the place of the entire outer fabric heretofore used on rigid airships solely as ahull skin to reduce air re sistance, displaces a larger part of the inner gas cell fabric weight, and while resisting tangential stresses takes the place of shear wires, gas pressure wires and gas cells netting,thereby generally reducing weight of the hull structure, as well as amply resisting all inherent stresses when combined with structural elements as hereinafter further described. I

The single metallic outer envelope has longitudinal and circumferential stiffening members substantially integral with its inner surface, so that the tension in the skin cooperates with the stiffening members tending to prevent buckling of the stiffening members in a direction normal to the skin, and to entirely resist their buckling in the plane of the skin or sheathing,whereby the safety of the stiffening members is greatly increased, or their permissible weight may be reduced, or both. This applies to all portions of the envelope where there is any'appreciable pressure due to the head of gas or to induced pressure within the hull.

The longitudinal stiffening members are substantially on the meridian lines of the ship and, except for special modifications,

they have a continuous curvature longitudinally, converging at either end into a means or structure providing a substantially rigid nose and stern cap. In the preferred form, some of the longitudinal stiffening members are enlarged, and for large ships two of them are designed as large girders forming kelson trusses one on either'side below the middle and well away from the bottom of the hull. Such kelson trusses with a number of transverse connecting trusses across the bottom of the ship, provide a rigid lowor hull structure. These longitudinal and transverse trusses also provide corridors and compartments for the accommodation of supplies, goods and passengers, as well as for the crew and inter-communication, and for outside car attachment in addition to serving their part in the structural unity and rigidity of the ship, thus largely eliminating what has heretofore been additional pr (extraneous structure to carry the useful .oa

The circumferential stiffening members or frames associated with the skin of the ship may be generally uniform, but? when of different sizes, the smaller ones may be of angle or channel section, and those of larger section may be built up rib trusses preferably in triangular section with one face of the section coincident with and secured to or part of the hull sheathing or skin.

7 The combined skin and stiffening members thus provide at substantially all parts of the ship an outwardly convex surface as well as rib curvature, both transversely and longitudinally, giving to the hull a general rigidity but with local elasticity and most advantageous distribution of parts for the resistance to the static stresses as well as internal pressure and aerodynamic stresses.

The skin with its stiflening members is internally interconnected by bracing of tie wires across and substantially in the plane of the transverse frames. Thus the lower hull portion at its sides has suspender wires running up to the stiffening members in the sides and roof or dome of the metal sheathing. These wires are preferably connected at the junctions of longitudinal and transverse stiffening members, and transmit the lifting strains direct to the lower hull or load portion of the ship. Stress wires also extend along chords across other parts of the frames. For local loads or exceptional local stresses additional internal bracing is suitably provided.

The sheathing is built up of numerous sheets or panels riveted together at their edges, and also riveted to the stiffening members. lVhile the use of such very thin sheets has resulted in numerous tests to provide the best joints for gas-tightness and strength, it is found that proper riveting and doping of the seam at the overlap serve all of the requirements of such a sheet-metal skin structure in combination with the stiffeners and bracing, as herein set forth. Modifications of methods heretofore known may be added. Such a hull skin reduces the gas leakage and inward air diffusion to a minimum heretofore never approached.

Some features of construction herein shown are disclosed in my co-pending applications for United States Letters Patent Serial Nos. 547,598, 558,541. and 635,410, while this application is addressed to additional subject-matter, as well as further coordination of some of the elements heretofore shown in the previous and co-pending applications, while in other respects substantially different elements or combinations representing more perfection of design and construction are herein specifically shown and described in particular embodiments.

As airships will be subject to great variation in size and specific construction to suit the purposes for which each is designed, this specification supplies the essential information necessary for the adaptation of the inventions to such requirements, which in an case will involve much variation in detai in view of which the specification and drawings are addressed to the principal features and their coordination with the entire structure without reference to specific detail.

In the smaller sizes of ships adapted to this construction, duralumin having a thickness of .008", with proportionately light stiffening ribs and wires, meets all conditions; while in the case of larger ships the thickness of skin sheathing is increased and in some may be .02" thick in order to accommodate the increased tangential and shear stresses.

In the small types of ships involving the v principles of this invention, the kelson trusses may be-omitted, and in place of large transverse trusses the bottom of the hull can be suitably tied by stress wires running on chords between points on the transverse frames, and the suspension wires or cables from the lift portion or dome of the ship can form connection through the bottom of the hull for suspension cables below to carry gondolas, power plant and supplies, and the useful load.

The structure in any of its designs provides for the stress resisting members connecting with and cooperating with the skin of the hull so that the lightest weight of bracing is permissible. The entire gas-containing envelope being of metal, the use of hydrogen becomes practical, although the structural and other advantages involved are equally advantageous when helium isused.

According to this invention the airship has a series of transverse frames tied to give them a non-deformable substantially circular shape transverse to the hull, with metallic sheathing interconnecting the peripheries of adjacent frames, forming the hull skin as well as the envelope and transmittlng the shear stresses from said frames. This provides a rigid ship particularly when a plurality of such sections extend from endto-end converging at the nose and the stern. Thereby the static loads are sustained when subject to the buoyant gas lift, and the principal stresses due to aerodynamic forces are automatically provided for by a builtup pressure obtained by one or more vents in the nose or well forward permitting increased air pressure in the air space, which in turn transmits the internal pressure to the gas, thereby building-up the tension in the envelope to resist compression due to aerodynamic forces.

l/Vhile air vents have heretofore been used in non-rigids to build up pressure on the fabric envelope, they have not been used heretofore for this purpose in any rigid airships because rigid airships heretofore have not used aconstruction in which any appreciable air pressure could be carried by the skin in cooperation with the structural stresses.

Illustrative of the inventions, specific embodiments are shown in the accompanying drawings, in which: I

Fig. I is a side elevation of an airship with a midship portion in vertical longitudinal section.

Fig. II is a vertical section transverse to the ship on line II-II, Fig. I.

Fig. III is a vertical longitudinal midship section, on a smaller scale, showing particularly a gas partition and its relation to ballonet diaphragm and transverse frames.

Fig. IV is a erspective interior view toward the stern mm a section at IVIV, Fig. I, showing hull structure-before insertion of partitions or ballonet diaphragms, and showing a form of erection equipment in dotted lines.

Fig. IV is a perspective fragmentary view of the starboard lower quarter with section of a sponson compartment and its connection with a transverse truss.

Fig. V is a rear elevation.

Fig. VI is a transverse section showing a modified frame construction particularly suited for small size ships.

Fig. VII is a section showing the frame and in bracing of a small size ship.

portant component parts and structure, ex-

cept that in Figs. VI and VII a modified internal bracing at frames is shown particularly applicable in the case of the smallest practical designs of ship.

The large size type has metallic sheathing 1, forming the skin throughout the ship, with certain slight exceptions in the lower portion, which will be hereinafter described. The sheathing, which is preferably made of sheet duralumin of very light gauge, is attached to transverse circumferential frames such as 22, where it may be secured in the manner shown in Fig. VIII. Each such frame is substantially circular and has a series of brace wires in the plane of the frame which are substantially as indicated in Fig. IV where wires 3 are chord tie bracing, and 4-4 and 555 are load wires or serve in the nature of suspension wires from the upper or lift section of the frame to the lower hull portion constituting the load section of the ship. v

Longitudinally of the ship and substantlally following the meridians of the hull are stifl'eners forming longitudinal girders 66-6, incorporated with the skin preferably riveted thereto or which may be formed as in Fig. VIII, wherein a crimped trough section has its legs riveted to the skin sheathing, thereby forming a triangular gird er in which the skin itself constitutes one face of the girder. The'top or ridge longitudinal 7, is preferably larger to provide ample strength for the catwalk 7 over the top of the ship. On either quarterbelow the middle the longitudinal stiffener is greatly enlarged forming rigid trusses 8-8 from end-to-end of the ship, whereby these longitudinal members serve their purpose as part of the rigid hull structure, but are of such sectional size as to. provide an interior corridor 99 sufiicientto accommodate goods. or supplies or passengers, as well as intercommunication and control equipment. At intervals these accentuated or .enlarged longitudinal stifiening members 8,

which are called kelsontrusses, are interconnected by transverse girders 1010-l0, forming with the kelson trusses arigid lowor hull structure. These enlarged longitudinal and transverse trusses preferably have fairing on the sides, of metal sheathing 1l11, thereby separating the interior of the trusses with a gas-tight wall from the gas space and also from the ballonet air space. As shown in Fig. IV, the compartment or space formed in the girder 8 maybe enlarged where desired, by a sponson 12 having suspender members 13 and deck beams 14 connecting at junctions of thetransverse frame and longitudinal members, thereby forming an enlarged cabin space with interior connection to one or more of the transverse trusses 10. Thesesponsons may have a double deck and companion-way or ladders, and all other conveniences for goods I or crew and passenger accommodations, as well as communication through the interior corridors.

As shown in Fig. IV in dotteddines, a cradle structure 15 provides for the support of the lower hull structure'before inflation, and the top suspender bar 16 carries suspender ropes 1717 17 connecting with means such as eyes 18 permanently; embodied on the outside of the skin with gas-tight connection, which provide for the support of the weight of the upper hull portion during erection and when not inflated.

Gas inflation valves 20 are formed at substantially the highestpoint of the shell having deflectors 21 on the inside serving to direct the incoming buoyant gas horizontally to prevent its mixing with the air it displaces. The buoyant gas space in the design shown is divided by four partition walls 22--22, preferably of fabric, having a reinforcement 23 with tie wires 24-24, so arranged that the peripheral edge of the partition can be secured to one transverse frame, and the tie wires to an adjacent frame so as to position the partition 22 midway between two frames and thereby permit ordinary bulging without interference with the brace wires of each adjacent frame. These partitions are united at a seam 25 with the fabric ballonet diaphragms 26-26, and hold-down wires 27 serve to hold the gas partition 22 in its predetermined position, leaving the ballonet diaphragm free to breath up or down, and adapted to take upon complete inflation position 26. shown in dotted lines, Figs. II and III. Each ballonet has one or more air vents 28 to let out the air displaced by the incoming buoyant gas, and thereafter seal the ballonet diaphragm.

\Vhen inflated the pressure in the balloncts is provided by a breather 29 admitting air pressure due to the speed of flight, into the forward ballonet and through passages 3030 preferably adjacent the lowest point in the hull, the air pressure is carried into all of the ballonets. An additional breather 31 may also be provided, adjustable so as to receive air from one or more of the propellers in order to build up an artificial ballonet air pressure. In this case all breather holes are preferably provided with check valves to prevent outward flow of air, the latter being handled through separate valves of the customary type 30*. Gas discharge valves may be a unit with the gas-inflation valves above mentioned. The ballonet pressure is exerted against the buoyant gas, thereby increasing the internal pressure throughout the lift section of the hull and directly against the inside of the hull skin so as to resist aerodynamic forces on the outside thereof.

-Near the stern, fins 3232 are sup orted between adjacent longitudinal sti ening trusses in planes normal to the hull surface, and preferably eight such fins are used providing the desired strength and sufficient area with lighter construction than in the case of a smaller number. Two fins on either side terminate in elevators 33-33, and the two lower fins terminate in articulated rudders, 34-34. These fins may be braced by fin braces 3535 in transverse planes. and additional internal transverse frame stiffening may be provided in the zone of the fins for their support and to resist the rudder and elevator strains.

The entire structure, as illustrated in the large ship-type, it will thus be seen involves a series of transverse frames substantially circular with internal cross bracing in the plane of the frame to make them substantially non-deformable, and provide for the suspension of the load in the plane of the frame, but having between such frames the sheathing of very thin metal, thereby forming interconnection between the adjacent frames which carries the shear stresses. The longitudinal members where used extend from end-to-end and are preferably curved throughout, converging at the nose 36 and at the stern-cap 37, where they are interconnected.

The rigid kelson trusses and transvers trusses provide for suitable support for a pilot or navigation car 38, and for the support of power cars 39, 39, 40 and 41. All power cars may have diagonal wires leading to girder members to transmit the driving force and to steady the posit-ion of the cars.

Types of air'ships involving the principle of this invention are subject to certain modifications. Certain features of modification for a small ship will be understood from Figs. VI and VII, in which a typical frame 42 has the stiff circular frame rib 43 and a number of suspender wires in the plane of the frame, two or more of which preferably merge into single suspender wires 45 passing through ballonet diaphragm 46, having at the point of penetration a suitable gas-tight joint such as a sliding joint or a telescoping gas-tight sleeve. The lower hull portion of the frame has chord ties 47 so that the lower or load portion of each frame is stiffened, and suspenders 45 carry the lift from the top portion of the shell or hull skin to points of attachment ofsuspenders 48 outside of the hull to suitably carry the load stresses of a car 49, having goods or supplies and motor capacity carried below and outside of the metalclad hull. In this modification most or all of the longitudinal members may be eliminated' The kelson trusses are here shown reduced to mere stiffeners such as 43. As shown in Fig. VII a series of cross bracing wires 50 in the place of each frame may be used to support the special strains in the fin zone, with chord wires 5151 to further stiffen the frame, and wires 52--52 may be used for resistance to local strains dependent upon the exact distribution of the stresses in any particular frame.

It will thus be seen that an all-metal, that is a metalclad airship results from the embodiment of the inventions herein described. wherein the gas-retaining envelope is one and the same as the skin of the ship, and being of metal it provides for the many advantages hereinbefore recited, while further advantages will be realized in many respects in the use of these inventions when applying them in the specific designing of any parmesses ticu'lar ship or ships. lhe particular relation between the sheathing and the cooperating structural elements, provides resistance to the stresses to which an airship is subjected. Dimensions of parts and their relative dimensions will of course depend upon the size and exact type of ship and the general requirements, and will be subject to much variation. The main features will, as first described, be applicable to ships of large dimension, while for the smaller sizes of ships, within practical limits involving the general conditions of buoyancy, features that may be modified are indicated in the description relating to small ships, and these also will be subject to considerable change for adaptation to each specific design.

Without limitation to the specific embodi ments herein shown and specifically described, What I claim and desire to secure by Letters Patent is: v A

'l. A rigid airship having a part of the hull consisting of a plurality of transverse frames braced in their'plane transverse to the ship to a rigid nondefprmable substantially circular shape and having the plural transverse frames interconnected by flexible metallic sheathing forming the skin and envelope taking the shear stresses of the hull and resisting the gas pressure stresses and means supporting the vertical fixed loads directly from said frames.

2. A rigid airship having a part of the hull consisting of a plurality of transverse substantially circular frame members structurally braced to a rigid substantially nondeformable shape, tension members extending from parts of each frame and confined to the respective frames tosupport vertical load strains, said transverse frames interconnected by flexible metallic sheathing resisting sheer stresses and forming the skin and envelope, a ballonet near the bottom of the hull and an air-vent therefor whereby ballonet pressure may be efiected to vary the pressure of the superposed gas directly against the inside surface of the metallic skin sheathing throughout the upper portion of the envelope. v

3. A rigid airship according to claim 1, having longitudinal stiffener-s or ribs coincident with and secured to the inner side ofthe hull skin envelope and outwardly curved throughout the entire midship section. a

A. A rigid airship comprising a continuous metal outer hull skin forming at the same time the sole gas-containing envelope with a diaphragm generally horizontal near the bottom of the hull forming a ballonet, stiflening ribs incorporated with said skin,

internal cross bracing ties in the plane of and across circumferential stiffening ribs to make a series of rigid non-deformable frames, thewhole constituting a structure to carry the static loads when inflated, one or more air vents so placed as to build up internal pressure in the ballonet and through the gas on the hull skin to compensate for increased aerodynamic pressure on the outside of the skin.

5. An airship comprising a continuous metal outer hull skin forming at the same time the gas-retaining envelope throughout the major portion of the hull with a diaphragm generally horizontal near the bottom of the hull forming a ballonet, stiffening ribs incorporated with said skin, internal structural bracing forming girder in a plurality of planes or circumferential stiffening ribs to form a series of independent rigid non-deformable frames, the whole constituting a structure to carry the static load when inflated, one or more air-vents arranged to build up internal pressure in the ballonet to the diaphragm and the. gas on the hull skin to react against increased aerodynamic pressure on the outside of the skin.

6. A rigid airship comprising a substantially non-deformable outer hull skin through the major part of the hull and in portion forming the sole gas lift-retaining envelope with a diaphragm forming a ballonet near thebo-ttom of the hull, stiffening ribs incorporated with said envelope and hull skin, the whole constituting a structure to carry the static loads when inflated, one or more air-vents arranged with respect to the lower part of the hull to build up pressure under the diaphragm to act on the gas to cause internal pressure on the hull skin to react against increased aerodynamic pressure on the outsideof the skin.

7. An airship according to' claim '6, in which the longitudinal stiffening ribs are of continuous curvature from end-to-end and integrally associated with the skin.

8. A rigid airship according to claim 6, in Which the hull sheathing with stiffening ribs securedbn the inner surface, is of double curvature throughout all areas.

9. A rigid airship according to claim 6, in which the ratio of length to maximum diameter is not greater than substantially four and one-half to one and having meridian stifi' frames of convex curvature throughout the entire midship portion.

10. A rigid airship according to claim 1, wherein the combined skin and envelope substantially carry the shear stresses, internal tension cables or suspenders in a plurality of transverse planes in each case extending only between different parts of one of the frames to carry the static load strains.

11. A rigid airship according to claim 6 having a plurality of longitudinal meridian rib forming with the continuous metal hull skin the stress-carrying connections between said stifi'ening ribs certain of which meridian ribs are relatively accentuated in sectional size.

12. A rigid airship according to claim 6, wherein two substantially enlarged longitudinal members form rigid kelson trusses along the sides of the hull skin and below the horizontal medial plane of the ship forming lateral corridors or compartments.

13. A rigid airship according to claim 6 having a plurality of rigid transverse interconnecting trusses extending from side-toside across the bottom of the ship forming communication and compartment passages between the enlarged ribs or kelson trusses.

14. A rigid airship having a plurality of rigid transverse trusses in circular form adjacent the inner side of the hull skin, fairing on said trusses separating them as to outside pressure from the other internal space of the ship.

15. A rigid airship having a plurality of rigid transversely positioned trusses in the circular form of and constituting essential stress-carrying members of the ships rigid hull separated from the other internal space of the ships hull by fairing covering the surface of said trusses facing the interior of hull and providing communication or compartments for passengers, equipment and the like.

16. A rigid airship according to claim 6 embodying with the hull skin a plurality of rigid transverse trusses extending from side-to-side across the bottom of the ship constituting structural members and communication and compartment passages and having a pilot and control compartment supported forward by one or more of the transverse trusses and communicating therewith.

17 A rigid airship as in claim 1,.having a series of suspension wires from stiffening members in the roof of the sheathing and converging to a lesser number of suspension cables passing through gas-tight joints in a plallllonet diaphragm and to the bottom of the 18. A rigid airship according to claim 1 having a series of suspension wires from stiffening members in the roof of the sheathing converging to a lesser number of suspension cables extending to suspension wires extending below the hull and supporting a car outside of the hull.

19. A rigid airship as in claim 6, and having means positioned at a plurality of points throughout the outsideof the top half of the hull skin permanently incorporated with the skin to form a gastight joint each at a point permitting load directly from a rigid memher associated with the skin, for the attachment of outside suspension means to temporarily carry the structural weight of the hull before inflation.

20. A rigid airship according to claim 6, having a plurality of suspension connections each forming a gastight joint with the out side surface of the hull skin and passing therethrough at points distributed throughout the top half of the hull skin and permanently rigidly connected to the stiffening members integrally associated with the skin.

21. A rigid airship as in claim 1, having a gas partition transverse of the ship extending from the inner surface of the skin at the top and sides and connected with a flexible ballonet diaphragm at a transverse seam near the bottom.

22. A rigid airship according to claim 6, having a gas-partition transverse of the ship sealed to the inner surface of the ships skin at top and sides and connected with the ballonet diaphragm near the bottom and means of support from the envelope to hold the partition in a plane between two transverse frames.

23. A rigid airship as in claim 6, having a gas partition transverse of the ship extending from the inner surface of the skin at the top and sides and connected with the flexible ballonet diaphragm at a transverse seam near the bottom, supports for the partition from the circumferential stifiening members to support the main portion of the partition midway between adjacent frame brace wires, and permit a limited bulging in either direction without interference with said brace wires.

24:. A rigid airship according to claim 1, having a plurality of gas-partitions transverse of the ship with sealed connection to the inner surface of the ships skin at the top and sides forming a plurality of gastight sections with the ballonet diaphragm near the bottom of the hull, gas inlet valves at top points in each section, air outlet valves at the bottom of the ballonet diaphragm and air outlet valves at low points in the ballonets.

25. A rigid airship having a non-deformable buoyant gas envelope, a flexible diaphragm secured hermetically to the sides of the gas envelope in its lower portion arranged to lie without under pressure during the gas inflation of the envelope and forming a ballonet near the bottom thereof of a minor capacity of the envelope when the airship is in operating condition, an inflation valve near the top point of the nondeformable envelope, and an air outlet valve in said diaphragm in a position during gas admission adjacent approximately the low point of the gas space in the envelope during the period of inflation.

26. An airship as in claim 1, having a gascharging valve with an exit adjacent the highest point in the interior of the hull shell with horizontally discharging outlet, whereby the flow of gas on inflation is prevented from mixing with the air being displaced during inflation and an'air-escape opening 7 is located near the bottom of the gas space.

27 An airship having a plurality of fins permanently secured to the hull surface and extending radially therefrom of which at least six of said fins terminate in articulated sections forming elevators or rudders and at least one having no articulated trailing-section.

28. In a rigid airship, six or more fins fixedly secured to the outside surface ofthe ships hull well forward of the stern, bracing from near the outer edge of said fins to the ships hull adjacent the base of neighboring fins, and rudder and elevator articulated sections supported at the rear of a plurality of said fins.

29. An airship according to claim 1, having stiffening ribs or girders'integrally associated with the hull skin and formed of polygonal or triangular section of which one face of the rib or girder is coincident with the skin or formed by the hull sheathing.

30. A rigid airship having stiffening girders integrally associated with the outside hull structure and projecting inwardly therefrom, said girders formed of pol gonal or triangular section of which one face of the girder is coincident with the hull surface and transverse or circumferentially disposed with respect to the hull, fairing on the faces of said girders projecting inwardly whereby the same carry the hull stresses and are proportioned of ample size to provide useful accommodations in their. interior with substantially no additional structure weight.

31. A rigid airship as in claim 4, having longitudinal trusses forming a structural part and carrying stresses of the hull, and proportioned of ample size to provide useful compartments without additional structural weight.

32.A rigid ralityof transverse frames each comprising a peripheral stiff member and each interconnected from its upper lift-carrying half airship consisting of a plu- 'with the metal sheathing of the hull skin.

34. In combination in a rigid airship rigid meridian hull skin of continuous curvature converging from the maximum diameter to the bow and conver ing from the maximum diameter forwaid 0% the middle to the stern, six or more fins extending radially of the axis of the ship with their outermost edge not more than the limits of a square of the helght and beam of the maximum section of the ships hull, and bein secured to the hull surface forward of a su stantial portion of the right hull structure of the ship forming the stern Where the hull section approximates half or more the maximum diameter of the ship articulated elevator sections attached to some of the lateral fins and an ar-.

ticulated rudder section forming the trailing edge of at least one of the fins, whereby the control elementsare brought into the zone of the free-flowing slip stream of air of the rigid airship. i

In testimony whereof, I have signed my name to this application, this 21st day of J anuary, 1924. I RALPH H. UPSON.

to its lower load-carrying portions by susi pension. members and independent of adjacent frame, thin metallic sheathing forming hull skin and buoyant gas-pressure retaining evelope rigidly associated with the stiff peripheral member of a plurality of said frames and forming a shear strain-resisting structure of the hull and a ballonet to maintain various gas pressures on the inside surface of the hull skin envelope.

33. A rigid airship consisting of a. plural ity of transverse frames each comprising a peripheral stiff member and each interconnected from its upper lift-carrying half to its lower load carrying portions by suspension. members independent .of adjacent frame, thin metallicsheathing forming hull skin and buoyant gas-pressure retaining en-

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