US1526120A - Semirigid airship - Google Patents

Description

Feb. 1o, 1925.

G. A. cRoccO smmexn Ansar? Filed sept. 26.*'1922 Patented Feb; 10, 1925.

i rUnl,1ran STATES GAETANO ARTURO CROCCO, OF ROME, ITALY.

SEMIRIGLID AI'RSHIP.

Application filedA September 26, 1922.` Serial No: 590,676.

To all whom. it muy concern Be it 'known that (io-terrano Awful-:o

Cnocco, a subject ofi the King of Italy7 re siding at Rome, in the Kingdom Vof Italy, have invented certain vnew and useful Im',- provements in Semirigid. Airships', ofv which the following is a specification.

The semirigid airships wherein,thelbendL ing and cutting stresses of the loads are bornel by a stiff lower frame owingto this fact lose the chief advantage of their'type, ie. their flexibility, and the stiff frame whenl the airship is travelling in exceptionally bad weather, if even momentary, is subject 'to break towards its middle.

In order to avoid this inconvenience one or more articulations may be proif'ided 1n the lower frame, where the' bending stresses! due to statical loads are on the average of little importance and leave the points .wherer the joints are tobear the dynamic loads and the occasionalstatical overloads bythe natural resistance of the envelope under pres sure. l

This can beV done `without l any special change in the framesv now-a-days-:used for semirigid airships, if the airship i's-allowedf,` under the action" of these dynamic `loads' or statical overloads, to deform freely `in `its longitudinal line, owing to the elasticity of the cloth whereof it is made.

In such case, however, `said deformation, thoughit occurs `gradually and steadiflfyghas the inconvenience to lessen the penetrating quality of the airship and `introduce dynamic perturbating actions.

Thus is itnecessary to eliminate it, or at least reduce it to be practicallyl of little value; and this invention has for itsobject structural arrangements designed in View of securing the aforesaid result.

They consist substantially in rope connections of the hinged sections carried out by connecting the ascensional forces acting on the baclcof the envelope, as it will be better hereunder explained with reference to the appended drawings wherein:

Figs. l and 2 respectively show in transverse and in a longitudinal section an airship with connections of the lower beam and the back of the envelope;

Fig. 3 shows in a longitudinal section an airship in accordance with the invention with a lower beam with acentral hinge, and an upturned `c,atenaryas in a suspension bridge connecting the beam with the back of the gas bag; l

Fig; il 'shows a longitudinal section of another airship also with a single central hinge for the beam, but with two catenaries instead' of one Fig 5 shows, also in longitudinal section, an airship with a double hinge beam, and with two crossing catenaries;

Figs. 6 and 7 show details of the -ca-tenary attachments.

Assume, by way of instance, it is proposed to render indeformable an air'ship of the ta-lian type, in which the ascensional force` is transmitted to a lower beam not only by means of the tension of the cloth of the gas v bagA on the sides, but also by means of rope connections with the back, as shown in Figs. l' and 2.

In-` both figures, l, l, l, is a rigidf frame which, by way of example has been illus ti-ated as" a triangular beam; 2, 2, are the sides ofthe envelope which transmit to it partially the lifting power; 3, 3, 3 are rope connections" wliichcollect the lifting power on the back of a section andV transmit it by means of ropes 4, 4, 4 tothe beam underneath.

Now by introducing (Fig. 3) a hinge 5 towardsthe middle of the beam and connectw ing' withcatenaries in an inverted suspen-V sion `bridge av part of the lifting power of the' ropes 4, shows inthe foregoing figuresq it will' be understood how, by suitably choose ing the extreme; points of attachment 7 of the :catenary and the positions of the loads 8,` the `bending momentdue to said loads, to the reactions of the catenary in the points 7, and to the residual lifting powers trans mitted to thebeam by the ropes 4, can be made to vanish.

In this arrangement of things it is of course necessary not to balance with the catenary all the lifting power of the ropes 4, and to leave a residual part so as to allow the catenary to eventually be able to develop a greater tension without its attachment points at the ropes 41 giving away.

rFhis happens precisely when through dynamic actions or through statical overloads, in the two sections of the beam, on both sides of the hinge, develop forces in a downward direction which by acting on the connection points 7 of the catenary mcrease its tension and therefore take up a larger portion 'of the lifting forcesv of 1. It will be understood how, within the limits of such lifting forces, the system thus constituted will not be appreciably deformed, and acquires therefore the capacity of sustaining eventual loads in the direction as indicated.

It will be also evident how the system lends itself to resist without deformation the action of eventual loads in the opposite direction, viz: in an upward direction.

In such case the tension of the catenary diminishes and therefore the ropes 4i increase, to the utmost, the residual lifting power transmitted to the beam; and the limit of indeforn'iability is exactly this maximum which corresponds to the vanishing of the catenary tension.

The rope connections above described secure therefore the indeformability ot' the whole structure` of catenary and hinged beam, and hence of all the envelope.

It possesses also the advantage of lessening the weight of the beam, for it substitutes to the fiat beam an element of greater height in resisting to a part of the stresses of pe-rn'ianent loads.

Instead of only one c-atenary, two as 6 and 9 in Fig. t and even more might be provided and the beam might have two or more hinged joints, 11, 1.2 with crossed.' catenaries 13, 13 as in Fig. 5, ditlerently connected with one another, according to the opportunities resulting in each case from the distribution of the loads.

The details of the connections 'of tie catenaries with the ropes 4l are illustrated by way of example in Figs. 6 and 7.

The vertical ropes 4, double or single, carry an eyelet 19 within which runs the rope 6 of the catenary. The sliding movement of this rope is prevented by stays 1G adhering to the rope. A little adherence will suffice because the differential tensions of the rope 6 are a small part of the required tension.

The structure above described constitutes z'. new type of stiifening in airships wherein the envelope concurs to bear the bending stresses of the loads. The upper catenary tension and the corresponding compression of the lower beam resist in every section the statical or dynamical flections of the loads, forming a. true resisting beam with member distant one from the other about the diameter of the section, and therefore in the best geometrical conditions to obtain the utmost lightness.

Claimsl. ln semirigid airships with a lower frame comprising a plurality of rigid tions, hinges connecting said sections, and substantially vertical rope connections between said sections and the top of the envelope where the vertical ropes are fastened by means of small catenaries, catenary connections in the shape of an inverted suspension bridge between a plurality of said vertical ropes, and which collect the lifting power from the back of the envelope and transmit it to the rigid sections of the lower frame where their ends are fastened.

En sen'iirio'id airships of the class as specified .in claim 1 and in which the lower frame comprises two hinged rigid sections. a. single large catenary connecting the rertical ropes and fastened at each of its ends to one of the sections of the lower frame,

3. In seinirigid airships of the class as specified in claim 1 and in which the lower frame comprises two hinged rigid sections` a plurality of catenaries connecting the vertical ropes and fastened at their ends to each ol tlie'said two sections.

4i'. .ln scmirigid airships of the class as specified in claim 1 and with a lower rigid frame comprising three hinged sections. catenaries connecting the vertical ropes` each catenarv fastened at its both ends to two of the hinged sections.

In testimony whereof I have signed my name in the presence of two subscribing witnesses at Rome in the Kingdom of -Italy this 7th day of September, 1922.

GAETA NO A RTURO CR OCC() lVitnesses ANToNio Lotvnooon'rra. VVILHnmr Scrutin.

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