US 2355084 A
Abstract available in
Claims available in
Description (OCR text may contain errors)
c. KURRLE 2,355,084
COLLAPSIBLE FUEL TANK Filed May 5, 1943 Patented Aug. 1944 UNITED STATES PATENT OFFICE COLLAPSIBLE FUEL TANK Christian Kurrle, Dayton, Ohio Application May 5, 1943, Serial No. 435,723
(Granted under the act of amended April 30, 1928;
The invention described herein may be manufactured and used by or for Government for governmental purposes, without the payment to me of any royalty thereon.
This invention relates to auxiliary fuel tanks for airplanes, and its principal object is to provide a collapsible fuel tank which will occupy only a small fraction of the shipping space required for metal tanks of the same capacity so that many more of the tanks may be shipped abroad to various theaters of the Second World War. A further object is to save strategic materials. It will be understood that during this war pursuit or fighter type airplanes are frequently sent on long missions requiring flights far beyond their normal radii of action, and that for such missions one or more auxiliary tanks are carried, usually of steel or aluminum and suspended from the bomb racks under the wings, each tank being connected by quick-detachable tubing to the intake side of the engine and being dropped when empty. Ordinarily such tanks are ,never recovered, hence each extended flight means the loss of one or more expensive metal tanks which must be replaced by a shipment originating from the United States before another mission is undertaken. The exceedingly high cost of merely supplying the necessary tanks to a group of airplanes operating in a remote theater is apparent without elaboration.
In the accompanying drawing forming a part of this specification- Figure 1 is a side elevation of bodiment of the invention;
Figure 2 is a cross section on ure 1;
Figure 3 is a cross section on line 3-3 ure 1;
Figure 4 is an enlarged detail in section of the bulkhead construction; and
Figure 5 is an enlarged detail of one of the seams.
Referring particularly to the drawing, the preferred tank body is made of a plurality of gores 6 of cotton duck, canvas or other relatively still, porous cotton cloth, so cut and sewed together as to provide a hollow body 1 having the well known form of a dirigible, i. e., circular in cross section but larger at one end than at the other, and uniformly streamlined except for the fittings and attachments to be described. The illustrative body is composed of eight cotton duck or canvas gores sewed together along their longitudinal edges to form seams 8, but there may be moreor fewer gores, the number'that is desired being proportional to the size of the tank. As shown in Fig. 3,
the preferred emline 2-2 of Figof Fig- March 3, 1883, as 370 O. G. 757) point, at both ends of the body. Each seam 8 has its free edges covered by cotton tape 9 stitched'as at In, Fig. 5. The cotton tape provides a stiffening means as well as a reinforcement for the seam. The gores are assembled and sewed together with the tank body wrong side out and when all the stitching is complete except for a length of about two feet along one seam, the body is turned right side out by pulling first one end, then the other, through the opening. Then the fittings to be described are installed, and the opening of the last seam is closed by stitching, as indicated at I I, Figure 2. I
To reinforce the tank and obviate. any tendency to collapse laterally, two or more bulkheads l2,
l3 are placed inside the tank. Each bulkhead is a vertical partition snugly fitting the inside of the tank and dividing the tank into compartments; and to permit the liquid fuel to flow from one compartment to another, each bulkhead has several openings l4, l5, I6. The two bulkheads are exactly alike except for size, hence the following detailed description of one bulkhead applies also to the other. Bulkhead l2 consists of two circular plies l1, l8 of canvas united by stitching I 9, with the edges of the two plies turned at right angles but in opposite directions, see Figure 4. A strip of cotton webbing 20 encircles the outtumed edges of the piles and is stitched thereto as indicated at 20a. Reinforcing strips or ribs 2l, each made of a strip of canvas sewed along its edges to the bulkhead, with a looped or gathered central portion extending for the entire length of each rib, provide stiffening means for the bulkheads. Both bulkheads are secured inside the body by stitching 22 uniting the peripheries of the bulkheads to the tank walls.
A filling opening 23 is made near the forward or larger end of the body,.and the usual metal collar 24 and cap 25 employed on fuel tanks are also provided. 'IA metal fitting 25 providing a vent and two metal couplings 21, 28-for the fuel tubing 29 are alsoshown. Two fuel tube 'couplings are desirable to permit use of a single model of tank with either of two well known types of pursuit planes. Reinforcing strips of canvas 30, 3| are sewed on the outside of the body to make possible the secure attachment of metal hangers the seams all converge to a common meeting 32 which engage with some conventional bomb shackle, here indicated diagrammatically at 33. By tripping the release (not shown) the tank may be jettisoned by the pilot while the airplane is in full flight. The bulkheads reinforce the tank in the areas adjacent the planes of hangers 32, so that collaps or deformation of the body due to stresses imposed by the load is obviated.
To prepare a collapsed tank for holding -fuel a resin glue is pouredthrough the filling opening 23 and then all openings are closed. Various tacky substances neutral to aromatic fuels and capable of penetrating the porous tank walls and hardening to waterproof and stiflen the walls may be used. A suitable resin glue is Plaskon glue made by The ,Plaskon 00., Toledo, Ohio. Then the body is rotated and tumbled so that the resinous glue spreads over all the interior surfaces, including the baflles and ribs, and air pressure is applied, for example by meansof a hose (not shown) leading to a compressed air tank (not shown) and coupled to one of the couplings 21, 28. Air pressure builds up on the inside and when the pressure is high enough the air escapes through the pores of the canvas, it particles of the glue, which gradually coats the entire outside of the tank as well as the inside. Then the compressed air line is disconnected, and the body is allowed to dry and set. Finally a coat of the resinous glue is brushed or sprayed on the outside walls and then allowedto dry and set. Th result is that all the walls, bulkheads, ribs and seams are made very stiff, so that the body is resistant to any stresses it may encounter while in service. The seams 8 when stifiened by the glue provide longitudinal ribs which are especially important to maintain the streamlined shape of the tank during flight, while the bulkheads become stiff enough to resist lateral or crushing stresses and to prevent deformation due to the weight of the fuel and the reaction of th suspension of the body from hangers.
The described fuel expensive than aluminum and being made of cotton will effect a large saving in strategic materials. Usually its capacity will be 75 gallons but tanks containing 125 gallons or more may be made. As fifteen collapsed tanks may be shipped in the space occupied by one metal tank, a huge saving in shipping space may be effected, which is of the utmost importance due to the submarine menace. Furthermore making the collapsed tanks is easily accomplished by any small manufacturer provided with sewing machines, textile shears, etc.; hence the manufacture of the tanks tank is lighter and much less.
carrying with presents no problem and may be undertaken at a large number of shops and small factories.
Obviously the present invention may assume various forms neither described nor shown.
What I claim is: 1. An auxiliary fuel tank for airplanes comprising a. streamlined, hollow body made entirely of longitudinally extending gores of cotton duck or similar heavy, porous, textile material, sewed together along their longitudinal edges with the seams projecting inwardly to form longitudinal ribs; bulkheads secured inside the body; said bulkheads being of the same material as the body and having perforations for passage of the fuel and reinforcing lateral ribs also'of the same material; the entire body including the longitudinal ribs, the bulkheads, and the lateral ribs bein stiffened and sealed by a resinous, waterproof glue which is neutral to aromatic fuels; the stillness being such that the tank maintains its original shape when partly empty and subjected to the aerodynamic forces arising during flight.
2. An auxiliary tank for aircraft comprising a body wholly composed of gores of canvas, cotton duck or the like sewed together to form a streamlined container larger at one end than at the other and circular in cross section throughout its length; the seams of the gores being turned inwardly to provide ribs, said ribs extending longitudinally and converging to a common meeting point inside the body at both ends; the v entire body being sealed and stiffened by means of a resin glue permeating all the pores and coating all surfaces, inside and out; the converging ribs reinforcing the ends and substantially preventing collapse or deformation under the stresses set up during fligh 3. The invention according to claim 2 wherein hangers are secured tothe upper side of the body to permit suspension of the tank from the airplane; and partitions or. bulkheads made oi. the same material as the body are placed inside the body to reinforce and prevent collapse thereof due to the stresses imposed by the weight of the fuel acting at the points of suspension.