US2918005A - Sheet propellant - Google Patents

Description

Dec. 22, 1959 G. SCHECTER ET AL SHEET PROPELLANT Filed Oct. 51, 1956 INVENTORS GEORGE SCHECTER WlLLlAM J. KROEGER BY a. QQM Zmm ATTOR N EYs 2,918,005 Patented Dec. 22, 1959 2,918,005 SHEET PROPELLANT George Schecter and William J. Kroeger, Philadelphia,

Pa., assignors to the United States of America as represented by the Secretary of the Army Application October 31, 1956, Serial No. 619,644

4 Claims. (Cl. 102-49) (Granted under Title 35, U.S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental I purposes without payment of any royalty thereon.

This invention relates to a propelling charge for a projectile fired from a gun and has for an object to provide a propelling charge in a form suitable for use without the necessity for usual enclosing case being present, whereby a substantial saving in weight is made possible. Another object is to provide a propellant capable of giving a close approach to uniformity in presfixed ammunition has been customary, a soft metal.

cartridge case being used to house the propellant and secure the projectile in an end portion of the cartridge case. With the advent of recoilless guns of the Kroeger- Musser type disclosed in U.S. Patent 2,466,714 dated April 14, 1949, efforts have been made to keep the gun and ammunition as light in weight as is possible for desirable portability in rough terrain. The cartridge case for ammunition for that gun was made as.light as was reasonably possible. It was made perforate vfor a substantial part of its length for the primary purpose of'allowing the gases to be directed radially. outward and then rearwardly through the nozzles for overcoming the thrust of recoil. As a result a considerable reduction in weight of the cartridge case was efiected. It was realized that the lightest cartridge would be one having no propellent case at all. Making the propellant separately loaded after the manner of the larger caliber g ls; Was npt feasible because too large a proportionof-the propellant would ,be blown rearwardly and its effectiveness in raising the gas pressurebehind the projectile lost, t h u s reducing the, effectiveness of the weapon.

According to the propellent case has been eliminated making possible a great saving in weight of the ammunition that has to be supplied to the gun while at the same time reducing the loss of unburned propellant that would otherwise be blown rearwardly.

More specifically, the present propellant is made in sheet form with portions of it connected to reduce the portion of discrete particles of incompletely burned material being blown rearwardly. Still more specifically, one connection is the sheet material itself whereby the entire unitary mass is a spirally wound sheet of propellant. Another type of connection forming a unit is between discrete layers fitting over a supporting arbor or tube, which may or may not be filled with black powder or other igniter material and which when so In the smaller caliber guns,

present invention, the weight of the 2 filled will have a number of perforations through the walls thereof whereby flames of the igniter material will ignite many of the layers.

Fig. l is the top plan view showing a sheet constituting one embodiment of this invention.

Fig. 2 is a section on the line 22 of Fig. 1.

Fig. 3 is an end view of the roll of the sheet material of Figs. 1 and 2.

Fig. 4 is a side view of a collection of circular discs cut from the material of Figs. 1 and 2 and mounted on a supporting tube. V

Fig. 5 is another collection of circular discs cut from the material of Figs. 1 and 2 but being of uniform diameter.

Referring to Figs. 1 and 2, a corner of a sheet of propellent material 10 is shown as being provided with protuberances 11 formed during the process of rolling the material in manufacture. A nominal, though not exact, composition of a typical sheet material is nitrocellulose 55%, nitroglycerine 43%, ethylcentralite 2%,

lamp black 2%, moisture 1%, the total volatiles of the foregoing being about 50%. Many other compositions for a sheet propellant will be apparent to those skilled in this art. A typical size for the sheet material of Figs. 1 and 2 is a thickness of .0205 inch for the sheet with the protuberances rising .013 above the surfaces of the sheet, the protuberances being .10 inch in diameter, and spaced between the centers about .375 inch. The geometry of the elements of the sheet propellant can be varied to suit the ballistic requirements of special weapon systems.

In Fig. 3, a sheet of the material of Figs. 1' and 2 is shown asrolled into a spiral roll 12 upon a tube 13 after the manner in whicha carpet is rolled. The supporting tube 13 serves as a structural element of the cartridge and also as an element of the ignition system as is descnbed more in detail for the embodiments of Figs. 4 and 5. Although the embodiment illustrated in Fig. 3 is not the preferred one, nevertheless 'it possesses an advantage in that the spaces between layers due to the protuberances are effective in providing a path for the ignition gases to impinge on themajor portion of the ignitable propellent. surfaces thereby facilitating the ignition process and initially directing the products of combustion longitudinally of the gun and rearwardly.

In Fig. 4 is shown a large quantity of discs 14 a majority of which are of varying diameters, stamped from the sheet material from Figs. 1 and 2 and mounted upon a supporting tube 15 filled with black powder 16, the tube 15 being perforated so that the products of combustion of the black powder may radially outwardly move into and ignite the sheet propellant. A special purpose of the embodiment shown in Fig. 4 is the use of the propellant charge in a recoilless rifle having a central venturi opening, the tapers to the charge being effective in providing increasing spaces, one directed to-' ward the rear venturi opening and the other directed in an opposite direction toward the gun barrel but not shown for the full length. The purpose of the increasing annular areas is to accommodate the increasing flow of gases. The taper forward and that rearward may or may not be the same. The black powder in the tube 15 is ignited by any appropriate form of primer and the tube 15 may or may not be secured to a projectile in front of the propelling charge. Where tube 15 is not secured to the projectile, provision must be made for centrally supporting the end of reduced diameter of the propelling charge. The size of the charge depends upon the gun in which used, but one size found desirable for a mm. recoilless rifle had the large end 3.25 inches in diameter with a half-dozen sheets of the propellant E the. left end, the diameter of; the smaller disc was 1.55 I A inches while the 'met'al tube--15. was 1.157 inches in the i outside dia met'erfl 'lnasrnuch as each disc has :a 'EhiCk-e i ness of .025 inch-F013 inch, the total length f the I tapered discswas 254 ti'mes this, inasmuch as there were i of the same uniform diameter 17 at the right end; .At

' 2i4 discsin theen'lbodment shoWn.-' i

p In Fig '5, the propellant there illus'tratedis a quantity of discs all of the same diameter 17a mounted upon a I metal or consumable tube a and .filled with black powder 164, the tubefbeing perforated to facilitate ignition i 1 of the many sheets mounted thereon. The embodiment i shown in Fig. '5 finds: specialusein the .Kroeger-Musser type recoilles's rifle disclosed in ULS. Patent No; 2,466,714 l 1 I A dated April "14, 1949; Thetube. 15a is secured to a projectite 1 18. Propellanti supporting tubes in Figs; 3 and 4 may also'beof consumable material; i i 1 i 1 i Among the advantages of the present invention may be l nrent'ionefd the reduction weight of thecart ridg'e because "of the elimination of the cartridge case, this reduction being as much'as about to where the standard 'haps this reduction in weight of propellant =ejected may 20%? in the amount of iunburned. propellant which is h ejected ream/army through the ventu 'ri openings. :Per- 5 f 1 .3- eihs we s t p pe m c r w d s s e ml in=whiGhsaid-1 y6rs iarecireular; discs, mounted on saide tubular supportsuch that a perpendicular to their; side. j t

=taces is parallel to the longitudinal; axis of. said: tubular i j support,- said; tubular support being perforate, and said z layers of discs gradually= reducing in diameter toward 1 l 1 both ends of said tubular support. a

I be said tolbe duetothefact that the major portion of- 2 i thepropellantbeing of: sheet material is'connected withi i adjacent sheets either through: the supporting tube on 5 lwhich rnountedor as inFig.=3 by the same being a i continuous. sheet ornearly $0.. I An important advantageinitheipr'esnt. invention? is "the better reproducibilityiin' 3 results; due "to-thefi xed 'geo'metryof propellant and the uniform space distribution during ignitiont The emboldh merits; illustrated in Figs. 4fand 5 are preferred'forthe' 'be fin o'rsp'i'n stabilized; Either therollor disc propellant is retained and fixed in position between and with respect to both aprimer and a projectile. A flexible, tough, consumable covering that is light in weight and impervious to moisture should be wrapped around the propelling charge of this invention and enable such charge to be fixed, retained, and protected substantially as 'fully as does the usual metal case yet without the usual weight of the metal case. The long taper toward a central venturi provides increasing space through which the products of combustion move rearwardly. In a usual cylindrical propellant chamber afsaving in weight of the gun is possible because the large prior art longitudinally tapered gas passageways outside the propellant chamber 1'10 longer need to be as large with the result a reduction in size or possibly the elimination of these previous passageways eflects a substantial reduction in weight of the gun.

We claim:

1. In combination with a projectile, a lightweight propelling charge a major portion of which needs no of comparison j is T the usual; metalcartridge case for i i e containing a propellant charge; 'Another; advantage of i the present invention is: a reduction of about '15 =to rtroe e'emuss'erreturnees tide, and of these,- those illusitratedin Figs; 4 ahd fi are arranged to direct the product's: I otcotnb'ustion initially radially outward. The cartridge tor-use with either the roll or-disc type propellant may f Jayer, whereby ignition ofsaidiayers -outward-from saidtubular support; p

: 2. A, lightweight propelling charge according to claim 1, 4 4 :ini whic hsaid layers, are circular discsmounted on said; tubular support such that: a perpendicular to their side faces is parallel to the longitudinal axis of said tubular support, said-tubular support being perforate, and. said discs gradually-reducing in {diameter towardone endiojf said tubular support.

-.rigid case, a rearwardly extending substantially inelastic e tubularsupport; filled :withan explosivefor ignition of Zsaid propelling charge, said propelling charge comprising 1 I p I a-pluralityof layers of sheet propellant, means for mounting; saicl layers of sheet propellant. on said tubular sup? port passing through said layers to maintain; substantial; 3 3 i I I uniformity in arrangement with zrespect to each layer i and the longitudinal :axis of. said tubular support, each:

layer of sheet propellant being; solid and :imperforatein; 1 i l planes-parallel and perpendicularto the longitudinal axis f fOf-Slld tubular support and .radiallybeyond said tubular g a support; each layer of sheet: propellant; having .protuber;

ancesafiixed to at least one face of said layers, said pro' tuber-antes; spacing each layer a uniform distance apart from a contiguous layer, the outer end; surface of; each 1 i I i protuberance; engaging a side; surface: of an: adjacent proceeds radially. e

' 1 4; l h w ht t ave l ha :n si M ni 5 i i p of which is-of a type ineedingnn rigid-case, comprising; I

a plurality sot connected imperforate layers of sheet I propellant,- means for mounting: said. layers on at least: one: substantially inelastic support passing through said; g 1

- ay s; chJay r h v pr t r ce pa n ne layer,

i a uniform; distanceiaparttrom a contiguous -layer, where-: e

by products of combustion will be: directed outwardly. a 1

- between unburnedlayer portions, such fixed geometry of arrangement of propellant in a gun with respect to surface distribution and with respect to progress of combustion enables an improved approach to uniformity in ballistic reproducibility between successive charges by maintenance of uniform spacing between said layers during ignition, said layers being integrally connected in a single sheet wound in a roll having ageneral spiral cross section.

References Cited in the file of this patent UNITED STATES PATENTS 989,375 Luciani Apr. 11, 1911 1,274,258 Gerdom July 30, 1918 2,421,522 Pope June 3, 1947 2,436,826 Regadet a1. Mar. 2, 1948 2,466,714 Kroeger Apr. 12, 1949 2,494,562 Kessenich Jan. 17, 1950 FOREIGN PATENTS 207,540 Switzerland Feb. 16, 1940

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