US2681619A - Rocket projectile - Google Patents

Description

June 22, 1954 E. F. CHANDLER ROCKET PROJECTILE 2 Sheets-Sheet 1 Filed May 13, 1949 I t il INVENTOR. EO Wdra F fiend/er June 1954 E." F. CHANDLER ROCKET PROJECTILE 2 Sheets-Sheet 2 Filed May 15, 1949 r u e. V .v 3 l L f Patented June 22, 1954 UNITED STATE rarer OFFIC 4 Claims.

This invention relates to improvements in rocket projectiles and other automotive devices.

An object of the invention is to provide a high explosive shell and the like which can be fired substantially without recoil.

Another object of the invention is to provide a rocket projectile which may be manufactured, loaded, stored, handled and fired in substantially the same manner as standard fixed ammunition.

A further object of the invention is to provide a rocket projectile which may be fired from a closed breech, light weight, portable gun substantially without recoil and substantially, depending upon the caliber, without flame, smoke, or noise in the vicinity of the gun position.

Another object of the invention is to provide a rocket projectile specially adapted to be dispatched from breech-loading quick-firing and/or automatic arms.

Still another object of the invention is to provide a rocket projectile which will greatly increase the range, firepower and accuracy of arms adapted to be carried by the individual foot soldier, being fitted for use in such arms.

Another object of the invention is to provide a rocket projectile in which the consumption of a large part or all of the rocket propellent powder charge is not depended upon for launching the shell, and which is adapted for use in direct fire arms, or in mortar type arms adapted for high angle firing.

A further object of the invention is to provide a rocket projectile which is launched from a closed breech gun in such a manner that all, or substantially all of the rocket propellent powder charge is available for accelerating the flight of the rocket over its course, thereby greatly increasing the impact of the shell upon the target, as against depending upon a high initial or muzzle velocity, obtained heretofore by the rapid combustion of the rocket propellant during the launching period, in which case the energy of the launching impulse has been gradually dissipated during the flight of the shell.

Still. another object of the invention is to provide a rocket projectile which upon firing, leaves the gun at a high velocity as the result of the explosion of an auxiliary powder charge within the projectile and, in such manner that a relatively small volume of gas is instantly released, when it has reached a predetermined high pressure and is therefore adapted to exert a powerful, momentary power impulse of such short duration that the energy is largely absorbed in driving the projectile from the gun substantially without recoil.

Still a further object of the invention is to provide a rocket projectile which, upon firing, is driven from the gun at a high muzzle velocity capable of setting the projectile on its course, by the instantaneous impulse resulting from the instant release of a charge of gas at a predetermined high pressure and in which the release of such gas energizes the rocket propellent powder charge so that, at a predetermined point beyond the muzzle of the gun, the flight of the projectile is continued and accelerated along the course impressed upon it upon firing, by the reaction of the rocket propellent charge,

Another object of the invention is to provide 5 a rocket projectile which is adapted to be fired in the manner described, in which the initial or launching impulse eiiect may be modified to meet specific firing conditions and equipment, as for example, where the projectile is to be discharged from an automatic gun and in which case energy generated upon firing the projectile may be utilized for actuating an automatic loading and firing mechanism and for other purposes.

A further object of the invention is to provide a rocket projectile of the type described, in which the nozzle jets may be angularly positioned to spin the projectile for gyroscopically stabilizing the same in flight, and in which the propellent rocket charge is sealed in a protective coating against weather conditions and the like, and which is readily combustible upon firing, yet in which, by its novel method of launching, the gas discharge for initially driving the projectile does not foul the gun parts.

Other objects and advantages of the invention will become apparent from the following description of a preferred embodiment thereof as illustrated in the accompanying drawings, and in which,

Figure l is a longitudinal sectional view of a complete rocket projectile according to my invention,

Figure 2 is a left end elevation of the projectile shown in Figure l,

Figure 3 is a left end elevation of a modified form of the projectile shown in section in Figure 4 and illustrating the use of a plurality of launching charges instead of the single charge shown in Figure 1,

Figure 4 is a fragmentary sectional longitudinal view of the modified form of projectile shown in Figure 3,

Figure 5 is a fragmentary longitudinal sectional view showing a third modified form of rocket projectile having a single nozzle and equipped with guide fins,

Figure 6 is a left end elevation of the projectile shown in Figure 5,

Figure '7 is a sectional elevation taken on plane 'i-l' of Figure 5, V

Figure 8 is a fragmentary sectional elevation of a fourth modified form of the invention illustrating means for multiplying the explosive force which may be obtained from a given powder charge, showing a gun with projectile disposed therein, and,

Figure 9 is a perspective view of a cartridge constructed in accordance with a preferred form of the invention.

Figure 10 is a sectional plan view taken on plane ill-4U of Figure 5.

Rocket propulsion of projectiles carrying high explosives for ordnance purposes and the use of rockets'for other purposes is now well established. Modern warfare has made increased and insistent demand for use at the immediate front line of combat encounter of larger caliber and heavier V projectiles than can be fired from prior art weapons with which the individual foot soldier can be armed, or which may be fired from light structure mobile guns.

The increased use of artillery, for the satisfaction of this demand, is prohibited by its initial impedance and unsuitability for advance by portage, and by the mass of carriage, barrel and mechanism being too great for light weight highly mobile equipment. The field equipment now required by armies must be light, fast, and extremely mobile and in present military tactics speed and mobility is of ever increasing importance, such as to subordinate factors of economy previously considered to be dominating, and which were thought to exclude consideration of rocket propulsion for projectiles.

Accordingly, rocket projectiles, because they may be'fired from a light Weight tube or trough, have found an important place in modern military and naval operations. The weight of the ammunition is comparable with that used by artillery pieces but the means for launching the same is extremely light. and highly mobile. As is wellknown, a rocket projectile fired from an open tube or trough produces no recoil. However, the

rearward discharge from the rocket motor, upon r firing, hasbeen a serious limiting factor militating against the application of rocket propulsion to a number of important uses.

This rearward flame-blast is dangerous to personnel, since it presents a serious fire hazard for a considerable area behind the launcher position, and it also discloses to an enemy the position of the rocket launcher. The seriousness of these objectionable features becomes more obvious and of greater tactical importance as the rocket arm is carried closer to the area of combat encounter.

Also, the back-fire from the rocket motor has precluded its use in light guns mounted in turrets or other confined spaces. It has been proposed to fire rocket projectiles from a closed' Cil the various elements constituting the modern rocket motor, but little progress has been made in the development of a system in which full advantage is taken of the important features of the rocket motor as it is known today, plus means which bring it into direct line as an important factor in a substantially new type of arm. The present invention provides such means.

This invention is also a continuation of the inventions disclosed in copending patent applications of the present inventor which matured: into patents as follows: Serial Number 545,585, filed July 19, 1944, for Rocket Projectile Patent No. 2,500,117 dated March 7, 1950; Serial Number 507,613, filed July 28, 1945, for Rocket Projectile Patent No. 2,524,591, dated October 3, 1950; and Serial Number 416,442, filed October 25, 1941, for Projectile and Method of Shell Propulsion, Patent No. 2,504,648 dated April 18, 1950.

In order to understand clearly the nature of this invention, and the best means for carrying it out, reference may now be had to the drawings, in which like numerals denote similar parts throughout the several views.

As shown in Figures 1 and 2, the rocket projectile includes a rocket motor body 55 which may be formed of tubular metal stock if desired, being reduced or constricted as at l2, and then flared convergently as at 14 toward its rearward or leftward end as seen in Figure l. A nozzle block 18, made of metalor other suitable material, is cut away longitudinally as at it, from front to rear, to form individual jet nozzles 55, of which six such nozzles are shown in Figure 2.

It is seen that the surface of the nozzle block i8 conforms to the overlying portions i2 and it of the rocket motor body it, and the latter may conveniently be spunover the nozzle block $8 in assembly and thus hold the parts tightly in place. An axial bore is formed through the nozzle block from its rearward surface 2! to its inner end. A cartridge 26 is threaded at is into this axial bore, by any suitable means such as a pin wrench inserted into recesses 22 in the outer face of the cartridge. The cartridge 25 includes a percussion cap or other form of igniter Q8 communicating through a fiame passage duct 55 with an explosive powder charge 25 adapted to be ignited by actuation of the igniter 43.

At the right hand end of the initial propellent charge 25 seen in Figure l, is a disc at comprising a frangible seal, adapted to be ruptured by a predetermined pressure from the ignited powder 26, and thereupon allowing gases generated therebyto pass through the gas discharge passageway 44 out of the nozzle block axial bore and into the combustion chamber or reaction zone d2. These gases are then free to flow toward the left as seen-in Figure 1, through the jet nozzles H5 and out from the rearward or leftward ends of such nozzles, for propelling the projectile.

Thepowder 25, burning under pressure, is thus completely'consumed, generating sufficient pressure to burst disc 15, and the hot high pressure gases release a sudden high pressure for actuating the jet nozzlesto produce rearward thrust. At the same time, these hot, high pressure gases from the charge 25 also serve -to ignite the disc or layer It! which forms the rightward wall of the combustion chamber 42 as seen in Figure 1. This layer 4| may be a layer of quick-burning ignition powder for insuring the start of combustion of the axial charge 40 and of the charge 38 surrounding the latter. The rocket propellent charge 38 is of any suitable rocket powder composition, and may be molded in the form of a hollow cylinder, with a center core 40 of less densely packed powder of the same or different type to insure uniform surface burning for even generation of gas pressure. The layer 4| may also, if desired, be a delay action powder, so that ignition of the main propellent charges 38 and 40 may not take place until a predetermined time interval has passed.

It is thus observed that the cap 48 is first ac tuated by means of a firing pin or other means, actuating the charge 26, bursting the disc 46 and allowing the propelling gases to enter the combustion chamber 42 and to leave rearwardly through the nozzles l5, launching the projectile. Because of the substantial absence of recoil, it is believed the high velocity drive, which serves to launch the projectile may be a reaction effect in which some of the energy is absorbed by the projectile and gun parts, the rapidly traveling shock-wave, which is believed to occur, impinging upon an internal portion of the forwardly moving projectile, to drive the same while some of the energy of the small volume of rapidly expanding gas is dissipated in the progressively expanding or increasing space within the barrel, between the butt of the projectile and the inner face of the breech block of the gun.

In the method described herein, the relatively small volume of gas generated is released at maximum pressure and almost instantly expands to atmospheric pressure, whereas, usually in launching a projectile the relatively larger quantity of powder necessary, upon detonation within the gun breech, first develops a high pressure and then this pressure is reduced as the gas expands during the forward movement of the projectile in the gun barrel. In the former case, the gas is or can be completely expanded Well within the length of the gun barrel, hence there may be no flash or smoke from the gun muzzle as the projectile leaves the barrel.

Nor is there any explosive noise upon firing In the latter case however, where large quantities of powder are employed, relatively, the gas evolved from the explosion of the relatively larger quantity of powder necessary to develop the desired muzzle velocity, expands beyond the gun muzzle with a release of flame and smoke and the noise of the explosion.

As seen in Figure 1, the forward end of the rocket motor body In is threaded at onto the rearward end of a shell body 28, with a heat insulating disc 31 disposed between the rearward wall 29 of the shell body and the forward end of the rocket main propellants and 38. This is not essential in short range missiles ordinarily, but in long range missiles the heat generated by the rocket propellant might affect the bursting charge 32 disposed in the body 28 ahead of time. Threaded into the ogival forward portion of the shell body 28 is a combined fuse 36 of any suitable impact or time delay type, and booster charge 34, adapted to actuate the bursting charge 32 upon reaching the target.

For the purpose of checking the principle un derlying this invention, experiments were made with a projectile one and one-quarter inches in diameter, weight being one and one-fifth pounds, in which the auxiliary disc bursting powder charge occupied a space 4 inch in diameter by H; inches long, and weighed 0.0017 pound, or about of the total weight of the projectile, loaded, ready for firing. The projectile was fired horizontally, from an 18 inch long, light steel tube having a' closed breech equipped with a firing pin and hammer. The object was to demonstrate that it is possible, upon pulling the firing latch, to instantly discharge the projectile from the gun a safe distance before full rocket action takes over, the target being positioned 35 feet fromthe gun muzzle.

In repeated tests, the projectile was dispatched against the target at high velocity, noiselessly and without the presence of flame or smoke. The operation resembles dispatching a projectile by means of compressed air. The absence of any substantial recoil is an important and interesting feature of the system. For comparison, the same projectile was fired from the same equipment, employing in this instance the relatively heavier powder charge normally required for dispatching a projectile weighing a pound and at the previously attained muzzle velocity. When thus fired, the recoil wrecked the light test stand previously used, and there was considerable smoke-haze and flame from the gun muzzle accompanied by a loud report.

It has not as yet been fully determined whether the ratio between the weight of the disc bursting powder charge and the total weight of the loaded projectile of approximately 1:700, which has been reasonably well established for projectiles of 1.25 to 2.00 inch calibers, will hold for all caliber ranges. It appears obvious however, from the work that has so far been done that, by the method disclosed, rocket projectiles of various calibers can be fired at relatively high muzzle velocities, from closed-breech guns in substantially the same manner as fixed ammunition is now fired, with little or practically no recoil and the absence of objectionable smoke, flame and noise to betray the gun position.

It is necessary only that the initial firing action carry the projectile far enough ahead of the gun muzzle to protect the gunner from. the nozzle discharge of the rocket motor of the projectile and depending on the caliber this distance may be of the order of five feet for a rocket fired from a shoulder gun to 30 to feet or more for larger calibers. A purpose is, as previously pointed out, to start the projectile on its course immediately the arm is fired, as in artillery firing, and at a sufficient velocity so that the rocket propellant becomes fully energized in time to continue the flight of the projectile on its predetermined course and to accelerate the speed of the projectile over all or a substantial portion of its trajectory.

It has become the practice, in order to quickly dispatch a rocket from a launching tube, to employ a type of rocket propellent powder which burns at a rapid rate with the result that most, if not all of the powder is consumed in. launching the projectile. Accordingly, in such case, the speed of travel and the range of the projectile depends almost entirely upon the energy impressed upon it initially and not upon the continued drive of the rocket motor jet. According to the present invention it is possible to employ a slower burning propellent powder and. thereby maintain a substantially constant pressure on the rocket motor power jet throughout a greater portion of the flight, thereby increasing the range and, due to the accelerated velocity causing the projectile to strike its target with greater force.

This is made possible by the firing method described herein which does not depend upon immediately energizing the rocket propellent 7 means for starting the projectile on its course. This is a feature which adapts projectiles constructed in accordance with the invention to use as ammunition for various types of light, highly mobile, quick-firing and automatic arms. Rockets have been fired from mechanically operated and mechanically automatic feeding devices. What is referred to herein, however, pertains to automatic arms which depend for their operation upon energy derived from the firing of the ammunition, which may be utilized for loading, firing and/or cooking the mechanism as in so called gas-operated systems and the like employing standard fixed ammunition.

The explosion of the small powder charge, employed for bursting the frangible disc, as used in the 1 cal. projectile, instantly releases a pressure of approximately 38 ,000 pounds per square inch and it has been found, among other modifications that by increasing or decreasing the volume of the initial reaction space 42, in Figure 1, more or less of this energy can be made available for actuating the operating mechanism of an automatic loading and firing arm. This powder exploded under high pressure is totally consumed so that the gas discharge is clean and better suited to the operation of such mechanism than the gas discharge from the usual machine gun cartridge and less liable to foul the barrel and moving parts.

Ehis is because the gas, in the former instance, is generated and expanded under a diminishing pressure condition, with an evolution'of incompletely burned products of combustion. It will be understood also, that the pressure released upon the bursting of the frangible disc 46 may be increased or decreased by changing the thickness of the disc or otherwise modifying its resistance to rupture and/or by adjusting the eifectiveness of the powder charge, in any suitable manner, to meet a predetermined operating condition.

A rocket projectile of the order herein disclosed, while designed to adapt rocket type ammunition to closed-breech guns, breech-loading arms and the like may also be fired from a tube or trough in the usual manner. Certain advantages may thus be realized among which is reduced fire hazard during the launching of the weapon.

motor body being spun over the nozzle block r to form a plurality of individual jet nozzles 55 like those shown at it in Fi ure l, and adapted to receive gas from the combustion chamber .66 corresponding to the chamber 42 of Figure 1. A main rocket propellent charge is disposed to the right of chamber fifi in Figure l, but is not shown.

charge.

62 through the small passages 64, in a well known manner. In this manner the extremely high total pressure which may be released is uniformly distributed and lighter equipment may be employed than might be the case where a single explosive cell, of equal power is used.

To further indicate this method of multiplying the explosive force which may be obtained from a given powder charge, Figure 8 may now be examined. As shown, a cartridge IIB, having a suitable frangible head I26 is removably secured in a suitable housing IIlfi having a breech-block I26 of any suitable type and equipped with a firing means, such as the pin I28. Secured in the forward part of the housing H5 is a barrel I96, and in the barrel is shown a projectile of any suitable kind, as indicated at I08, the butt of which may rest against the shoulder I2 I. Any suitable means for releasably retaining the projectile in the barrel may be employed if needed.

A detent I I2 secured to the barrel by rivet I I4, may have a sear on its forward end extending through an opening in the barrel and into a circular groove Mil on the projectile, to releasablyhold the same in position, or magnetic means may be used. Upon rupture of the frangible disc l2ll, the gases are free to pass through the passage I22 to launch the projectile.

Figure 9 shows a cartridge constructed in accordance with a preferred form of the inventive idea. As seen, there is the shell E32 containing the powder charge, and having a rimmed cap I36 with percussion cap I3I for igniting the powder At the other end there is a cup shaped frangible closure or cap Hill which extends over the forward end of the shell I32 and may be secured thereon in any suitable manner as by cold soldering. By the arrangement shown, the projectile Hi8 may be directly driven from the barrel with much greater force and at higher velocity than would be possible by exploding the same quantity of powder back of the shell without interposing the rupture disc I20 as shown. In this manner the projectile may be driven through light armor plate if discharged at close range. It is preferred to provide a self contained unit, as disclosed, with the impulse means forming a part. 7

Referring now to Figures 5, 6 and 7, there is shown a rocket motor having a rocket motor body 68 with main propellent charge I0 disposed therein, with combustion chamber 8|, the rocket motor body convergent as at T2 to form constriction at 83, and thereafter divergent as at 19 to form nozzle discharge opening TI. Stabilizing fins it are carried on the outside of the nozzle portion of the rocket motor body, radiating therefrom, and being held in position by a ring I4 secured thereto, the fins also being secured to the outside of the nozzle as by welding or the like.

In the reaction zone 8| and secured therein in any suitable manner is aspider 8!) having an extended portion 82 within which is a chamber 98 containing an explosive powder charge. The forward end, or rightward end as seen in Figure 5, of the chamber 98 is sealed by a frangible disc E00 clamped in place by a threaded ring I04 having a passage I02. At the rear of the chamber s8 is a percussion cap 86 or other suitable detonating means communicating with chamber 98 by flash duct 8 4, the cap being retained in position by the "threaded perforated portion at the rightward end of "the guide member 88.

Within the guide member 88 a rod 90 carrying a firing pin 91, the firing rod being retained against accidental operation by any suitable means as the shear pin 92, and also the rear end 94 of the rod is set-in, so contact with the rear end of the tail will not disturb the rod. When the detonating means 86 is actuated, the action is communicated through opening 89 to the charge in chamber 93, and when a predetermined pressure is reached within the chamber 99, the disc 599 is burst, and the gases flow through passage E92 into the reaction zone and out through the nozzle 18 to launch the projectile. At the same time the propellent charge 1'9 is ignited, the combustion thereof taking up and continuing the energization of the nozzle 19, to continue and accelerate the flight of the weapon.

Although I have described my invention in specific terms, it will be understood that various changes may be made in size, shape, materials and arrangement without departing from the spirit and scope of the invention as claimed.

It will also be understood that the casing H8 and cap 126 shown in Figure 8, and their counterparts shown at 132 and 19d respectively in Figure 9, which serves to contain the propulsive charge, may, if desired, be formed of suitable composition, such .as cellulose compositions, which are themselves combustible in the chamber when the propulsive charge is ignited. In this manner, since the members 118 and l 20 will then be completely consumed or burned up, there will be nothing left in the chamber to eject, and this will simplify the matter of keeping the chamber free and ready for use.

I claim:

1. A projectile comprising a projectile body having a first chamber formed therein, a main rocket propellent charge disposed in the forward portion of said chamber and incompletely filling the same, with the balance of said first chamber forming a, combustion chamber, nozzle means carried by said projectile body for driving the same and having communication with said combustion chamber to receive gas therefrom, said nozzle means having a recess formed therein, a launching charge disposed in said recess, means for igniting said launching charge to produce a quantity of high pressure launching gas, frangible means blocking passage of said launching gas into said combustion chamber until a predetermined launching gas pressure is reached, whereby launching gas is discharged from said nozzle mean to launch said projectile, said launching gas being adapted to coact with said main rocket propellent charge to initiate the actuation thereof upon entering said combustion chamber, whereby after launching of the said projectile, the flight and acceleration of the projectile is continued by gas produced by said main propellent charge.

2. The construction according to claim 1, wherein said nozzle means comprises a nozzle block having a plurality of nozzles formed therein and extending therethrough between said combustion chamber and the discharge end of said nozzle block.

3. The construction according to claim 1, wherein said nozzle means comprises a nozzle block having a plurality of nozzles formed therein and extending therethrough between said combustion chamber and the discharge end of said nozzle block, said frangible means comprising a frangible wall disposed intermediate said launching charge and said combustion chamber and adapted to block flow of gas to said combustion chamber until said launching gas from said launching charge has reached a predetermined pressure, whereby, upon reaching said launching pressure said frangible wall is broken, allowing said gas to enter the combustion chamber for discharge through said nozzles to launch said projectile, said launching gas being adapted to simultaneously effect initiation of the actuation of said main propellent charge, whereby after launching said projectile continues in flight.

4. A projectile comprising a projectile body having a first chamber formed therein, a main rocket propellent charge disposed in the forward portion of said chamber, with a combustion chamber forming a portion of said first chamber rear- Wardly of said main rocket propellent charge, a nozzle block in said projectile body, said nozzle block having a plurality of nozzles formed therethrough between the said combustion chamber and the discharge end of said nozzle block, with a plurality of launching charge recesses formed in said nozzle block with their discharge ends opening upon said combustion chamber, launching charges disposed in said recesses and adapted upon ignition to produce a quantity of high pressure gas for launching said projectile, means for igniting said launching charges, frangible wall means blocking communication between said launching charge recesses and said combustion chamber and arranged to remain whole until a predetermined launching gas pressure has been reached, said means for igniting said launching charges comprising a single detonating means communicating with all of said launching charges, whereby, upon ignition of said launching charges and production of said high pressure gas, said combustion chamber means is adapted to receive said gas upon reaching a predetermined pressure and to discharge the same through said nozzle block nozzles to launch the projectile, prior to actuation of said main rocket propellent charge.

References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 1,450,558 Maze Apr. 23, 1923 1,487,214 Dezendorf Mar. 18, 1924 1,994,490 Skinner Mar. 19, 1935 2,299,466 Coffman Oct. 20, 1942 2,408,252 De Ganahl Sept. 24, 1946 2,466,561 Standal Apr. 5, 1949 FOREIGN PATENTS Number Country Date 129,701 Great Britain July 24, 1919 379,664 Italy Apr. 2, 1940

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