US 2853946 A
Description (OCR text may contain errors)
Sept. 30, 1958 A. c. LC JEDESlNG ROCKETS 4' Sheets-Sheet 1 Filed Jan. 26, 1954 INVENTOB. 49 7 0 6'. Zacw'dzrzy Ira-L hi: ATTORNEY Sept. 30, 1958 Filed Jan. 26, 1954 A. C. LOEDDING ROCKETS 4 SheetS -Sheec. 2
ATTORNEY United States ROCKETS Alfred C. Loedding, Princeton, NHL, assignor to UnexcelledChemical Corporation, New York, N. Y., a corporati'on of New York I .ApplicationJanuary26, 1954, sen-lame. 406,103
3 Claims. (or. 102-49 atent Q A ice support" the "charge 'to'some degree and should therefore be structurally sound. and rigid to protect the same.
Suitable fins are provided on the containerat'the rear end thereof, and a warhead at the front end thereof. Duetothe noveiconfiguration of the charge "bars, the burning arearemains constant from the top (innermost 'bore end) to the'bottom thereof (in contact with thecontainer).
The invention will beimore fully described hereinafter,
embodiments thereof :shown in the drawings, and the invention 'willbefinally pointed out in the-claims.
In the accompanying drawing,
Fig. 1 is a side elevational view, partly in section, of the improved'rocket, taken Jon line 1-1 of Fig. 4;
Fig. 2 is a transverse section taken on line 2-2 of Fig. 1;
a centrol bore with the inner sides thereof, and having radialiside walls adjacent each other, the outer surfaces of the charge bars being peripherally spaced with Widening spaces therebetween filled with some lightweight structural material or special fuel to fill said spaces, and to enable. anadhesive to hold said bars in place, which is necessary due to high accelerating forces during flight andin order to protect against high shock loads and vibrations due to rough handling of the rockets during shipment. The charge bars are provided with an outer inhibiting coating'along their outer sides that are tangential to the bore of the enveloping container. Longitudinally the bars may be single units or made of a multiplicity of short members.
The bars extend almost the entire length of the rocket, save for a nozzle held by the container at its rear end, andfor a headcap at its front end to support a replaceable w-arhead, provided with explosives.
The charge configuration permits controlled internal burningresulting in a constant thrust and constant pressure during the combustion thereof, which is highly desirable.
The nature of the propellant is such that the ratio of the burning area to the nozzle throat area may remain low. This ratio symbol is commonly designated as K The nature 'of the propellant having low K and low chamber pressure allows the improved configuration of the bars which configuration permits proper burning of the charge (uniform burning area of a constant character throughout the depth of the bars). This arrangement does not require a large ratio of burning area to throat area. In case of composite charge bars consisting of a'plur'ality of units of short length, instead of a single bar, the abutting ends of the short units are completely inhibited, which however will not change the constant burning area of the uninhibited ignition surfaces of the bars, the remaining parts of the bars being provided with 'a'coating to inhibit or restrict burning to the constant factor of the ignition surfaces of the bars.
The configuration and the constituency of the propellant makes possible a charge which is self-sustaining circumferentially, to be insertable into a lightweight 'con- Fig. 3 is an enlarged transverse section of one of the charge bars shown in Fig. 2;
Fig. 3a is a diagrammatic view showing the evenness of the burning or burning surface propagation on ignition of 'a rod orcharge pellet;
Fig. 4 is an end view'of Fig. I, seen from line 4-4 of Fig. 1;
Fig. 5 is a side view of a warhead;
Fig. 6' isan end viewof Fig. 5,.seen'fromline"6'6 in Fig. '5;
Fig. 7 isa sideview of another warhead;
Fig. 8 is an end view of Fig. .7, seen from line 8 -8 in Fig. 7;
Fig. 9 is a diagram chart showingcurves indicating performance characteristics, such as acceleration, velocity and distance to-launch' warhead;
Fig. 10 is a diagram showing the drag and drag coefficient characteristics, as to transonic and supersonic regions;
Fig. 11 is a diagram showing the performance characteristics to launch warhead;
Fig. 12 is a diagram for air drag coefiicient values;
Fig. 13 is a section illustrating a modified form of charge bars arranged in the elongated cylindrical casing;
Fig. 14 is a section similar to that of Fig. 13, illustrating a further preferred form of said charge bars; and
Fig. 15 is a burning rate-pressure diagram of the propellants usable with this invention.
Similar characters of reference indicate corresponding parts throughout the drawing.
Referring now in more detail to the drawing, an example of a supersonic barrage rocket, such as air to air, is shown in Figs. 1 and 2.
An elongated hollow cylindrical container or shell 10 made of glass, plastic or the like, for example fibre glass cloth, flock or filaments suitably incorporated in a tubular plastic or vulcanized fibre structure, is of a thinness to render said container as light as possible, but to withstand necessary bursting stresses. At one end of said container, a nozzle 11 having an open bore 12 isinserted and frictionally held therein, aided by a suitable adhesive and/ or mechanical means. The contour of'the nozzle 11 is such that it conforms with standard practice, that is, it gradually increases in depth from its extreme outlet end to its peak, and then suddenly decreases in depth at 14, as shown by the curved portion 13, the end of which is formed as an abutment against the rear ends of the charge bars. Within the shell 10, there is longitudinally distributed and circumferentially disposed a'plurality of bars 15 of a specific cross-sectional area, the bars 15 being so placed as to form a central bore 16, as shown in Fig. 2. The 'propellent bars 'of this shape are practical to manufacture, easy to install, may be quickly ignited, and quickly consumed in a controlled manner to .form gases within the bore 16, which gases exhaust through the nozzle 11 under constant four fins .32..
I equahrelativelylow pressure. The length of bars almost equals the length of. shell 10, and thus the bars merit end 13 of the nozzle 11. I I
The propellent bar. 15, shown in Fig.
3 abase I 1 portion 20, with rounded corners a, and twoparallel I side walls-21, two slightly inclined walls 22in continua I 1 tion of the side walls. 21, and a top wall 23.; p I When a plurality of bars is. assembled in ashell, e. g:
the bore 24 of the shell (Fig. 2), and each bar has'its inclinedzwallszz in: faying parallel relationship with the I corresponding inclined walls of the 1 adjacent bars; I
.whercby the top walls 23 form a bore 16 of angular I I shape. I This intimate connection of a multiplicity. of bars I 15 provides n I unitary self-sustaining structure :of gen-I I I I I erallycylindrical contour with a desirable bore for the I I I emission of gases: The. spaces between the bars 15 and I the bore 24; of the-container 10 are filled with an art-- I hesive. 25 .tohold. the bars securely in position in their: I arrangement shown in Fig.2. I I I I I I I I The rear end. of shell 10 is provided with this 26, pr'ef- I erably six in numben I These fins maybe of the re- ZI I 3 tractible: type andmay be reduced of different configuration. I I I innumher to 3'0 4- I eight in number thecorners 20a. tangentially contact. with I I tional area in squarefeet,
. per second. I I I I I The density factory, of course, must .be considered,
which is /z,o for sea level conditions. I I
The above is well established formula for the air drag I calculation of aerodynamic bodies. I I I I In Fig. 11, the legends make the diagram tory I. I g. I.
In Fig. 15, the numbers of the: curves correspond to testnumbers of various propellants.- The curve for old black powder .is n-iarked' 101.- The n .SO-curve is marked .52 curve is I numbered 3.00, this: propellant having been obtained by I an .8 hours? tumbling; the propellant having the same constituents with only 4-hourstumblingis marked 300A. I I Numeral 400 indicates the n .69 -curve, and then .74 I
200, and the r z .53 curve by 201.
curveis indicated by unmet-211401., The symbol l in- I dicatesthe specific impulse curve. I I I i I I I I I The frontend of shell 10 is providedwith a head cap I I I I :27 secured to and within said shell .10.. Cap 27 has a I I bore 28 for a warhead '30i seated therein.- The bars -15 I I I .with their foremost ends abut against the base of headcap I Warhead 30 has a. pointed. nose 31 at its front'end and i I It is filled with suitable explosives of I I 1 I known composition, according to the uses I intended. I 1 Figs. 5 :and 6 show. onetype of such warhead ,'and Figs. I 7. and 8 demonstrate. another embodiment thereof. I
- .In :Fig. .5; the nose of the warhead is inclined about I nose is about 10. The warhead is either securely or loosely placed into the head. cap 27; in. the latter case,
in flight, the warhead may soar onward when the shell 10 drags away.
Fig. 3a shows diagrammatically, the cross section of a bar 15, surrounded by a layer of cement 15a, the bar being indicated by the character B. Each dot-dash section b b b [1, represents an equal burning surface of the charge bar B on progressive combustion thereof from b (corresponding to surface 23 in Fig. 3) toward b: (in the proximity of surface 20 in Fig. 3). This is to show the evenness of burning across the cross-sections of individual bars as the powder charge is being consumed. The coating terminates at A, leaving an exposed surface b to start the burning of the charge bar.
The factors of acceleration, velocity, distance to launch warhead, are shown in Fig. 9 with the nomenclature explained hcreinbelow. This Fig. 9 shows a diagram in which the abscissa is the time interval in seconds. The ordinate is the distance in feet and also acceleration which is measured in feet per second per second; the right-hand ordinate indicates the velocity, measured in feet per second. The curves shown are both theoretical, and actual (calculated) where air drag is involved.
These curves are calculated values obtained from well established formulae and indicate the performance of the rocket in definite fractional time intervals of the total duration of the thrust.
In Fig. 10, a theoretical curve shows the variation of the drag coetficient against the velocity, and also the air drag against velocity.
Drag is calculated as follows:
Drag==CDo X A X V =lbs.
wherein C is the drag coefiicient, A is the cross-secl -12 to the. horizontal, andin Fi 7 the inclination of the 1 I I I The establishedgeneration of low pressure gases under I I I 20 I desirable conditions isclearly indicated. I I
justifies the use of .a rela'tively low chamber pressure, i. e.
about 500 lbs. per-square inch, which-produces a-better I th n average value of the sp cific impulse. The. lo'w I 1 pressure. of about 500 lbs. per square inch obviously will I result in aimuch lighter chamber construction, as. cone I I pared to other rockets in which the propellants. must operate I at pressures of approximately. 1,500 lbs.- .per
square inch. 1
Fig. 13 shows possible use ofan intermediate tube 60,- .of plastic or thin metal, between the charges. and the I container. I
Another way of assembling the charges is to. have a. fiat. layer provided .with'spaced triangles; and thento install. the. bars and roll saidlayer to form a .cireularring, I I
the needed amount of triangles and hars being deter.-
mined to make a charge, and then to insert said chargering into the container. 1 I I I In Fig.g 14 a larger triangle 61 is shown, and the bars 15 are radially spaced at their bore end, as shown by the triangular spaces 62.
The following calculation is given by way of an example to show unusually high performance of the novel rocket:
The initial acceleration equals 812 g. Final acceleration is 1780 g. Average acceleration is 1450 g. (approximately 46,700 ft. per second per second).
The launching velocity V (neglecting air drag) is equal 32.2 (g) times 1 (specific impulse) times I (1 plus for a complete understanding of the inventive concept,
without being limited thereto:
The overall length from nozzle to warhead equals 9% inches. The distance from nozzle tip to the base of head cap equals 7 /2 inches.
The length of fins at the rear end of shell is 1% inches, including the inclined portion, whose length is A: inch. The outer diameter of the shell is %1 inch. The height of the charge bar is .150 inch, and the base width thereof is .150 inch. The height of the parallel sides of the nose tip and V is the velocity in feet self-eXpIanaQ The diagram of1Fig. 15 shows the variation of pro-. I pellant. performance against the chamber pressure and charge is .093 inch. The distance from top to top of the diametrically opposed bars is inch.
The height of the fin from the shell is inch, and its thickness is A inch. The diametrical distance from tip of fin to tip of fin is 1 inches.
The warhead is 2% inches long with the sides having a radius of 1 inch. The fins are inch, the head end flat inclination is A; inch flat. The tip offset is inch with a $4 inch radius, the angle of inclination being 12 degrees. The fin has a inch radius, and the end of the warhead tip is inch in diameter. From tip to tip of the fins, transversely, the distance is inch; and the diameter of the warhead is /2 inch. The length of the fins is Vs inch.
The rocket could be made to spin by modifying the fins.
The rocket can be ignited from its nozzle and launched from a manifold type base permitting only one or a large number of rockets, say 1,000, to be fired at the same time. A very fast burning strip of gauze impregnated with the same type of powder as used in the main propellent charge has been found satisfactory. This gauze strip extends from the nozzle to the forward end of charge and can be inclosed in a light paper or aluminum foil tube to cause the ignition to take place in the forward end of the charge. This will cause the entire inner surface of the charge to be properly ignited due to the fact that the hot gases, in order to escape, must flash rearwardly toward the nozzle opening.
The alternate warhead has a length of 2% inches with a 2-inch radius at its central portion, with front flat inclined inch at degrees; the distance from its center to its tip is 1 /8 inches; the length of fins is A inch; the inclination of the fin front is degrees; diametrical length of fin edge is /2 inch; and the diameter of warhead is inch.
The weight in lbs. is as follows:
Shell .0235 Head cap .0116 Nozzle .0043 Fins (6) .0011 Warhead .0313
Total empty weight, W, equals .0730 (without; propellant W,,)
Fuel or propellant weight equals- .0870 lbs.
Loaded (fuel) .1600 (Total weight smokeless type, and the charge arrangement provides internal burning which is restricted for constant thrust (130 lbs.), P (500 lbs. per square inch), I (240), duration (160 seconds). The Weight of the empty rocket equals .073 lb. Total weight of the rocket (propellent charge plus shell) thus equals .160 lb. (W
The foregoing configuration and contour of the charge, and disposition of the same, whereby a light-weight container is obtained, is made possible by the novel powder utilized, which combines low pressure combustion and 4 even propagation of the burning area to assure constant thrust. I have heretofore filed applications Serial Nos. 404,717 and 454,209, filed January 18, 1954, and September 3, 1954, respectively to which reference is made.
I have described several forms of my invention, but obviously various changes may be made in the details disclosed without departing from the spirit of the invention as set out in the appended claims.
1. In a rocket having a shell of light-weight material, said shell having a bore, a nozzle at one extremity of said shell and a warhead at the other extremity of said shell, in combination: a plurality of elongated propellent charges each having a substantially polygonal trans verse cross-section and operating at pressures of up to approximately 500 p. s. i., said propellent charges being adjacent each other in circular sequence,.forming a composite charge, and defining a relatively large internal bore, the surfaces of said propellent charges which define said internal bore being uninhibited for quick ignition thereof, an elastic inhibitor, filling the spaces between said propellent charges and said shell, said inhibitor forming with said propellent charges a solid unit in said shell, said composite charge with said inhibitor having a high degree of elasticity.
2. The structure of claim 1, wherein the adjacent pairs of said propellent charges define with said shell substantially triangular areas and said inhibitorin said triangular areas is an elastic adhesive.
3. The combination of claim 1, wherein said composite charge is a self-sustaining unit.
References Cited in the file of this patent UNITED STATES PATENTS 562,535 Hurst June 23, 1896 826,293 Unge July 17, 1906 1,277,942 Kaylor Sept. 3, 1918 2,466,752 Uhl et a1 Apr. 12, 1949 2,479,828 Geckler Aug. 23, 1949 2,552,124 Tallman May 8, 1951 2,602,037 Nelb July 1, 1952 FOREIGN PATENTS 2,576 Great Britain of 1854 516,865 Great Britain Ian. 12, 1940 612,998 Great Britain Nov. 19, 1948