US 3142959 A
Description (OCR text may contain errors)
-|2 E F BY INVENTOR. E L KLEIN ATTORNEYS E. L. KLEIN Filed Sept. 11, 1959 RANGE CONTROL OF SELF PROPELLED MISSILE Aug. 4, 1964 United States Patent l 3 142,959 RANGE CONTROL OF SELF PRGPELLED MISSILE Eugene L. Klein, Alexandria, Va., assignor to Phillips Petroleum Company, a corporation of Delaware Filed Sept. 11, 1959, Ser. No. 839,441 9 Claims. (Q1. 60-356) This invention relates to control of distance of flight of guided missiles. In one aspect it relates to apparatus for the regulation or control of the distance of flight of solid propellant, guided missiles.
It is often desirable to be able to control the flight range of a rocket or guided missile. One application for a range control system is in tactical or ground support rockets or guided missiles, where close control of range is required to place fire accurately and close to friendly ground forces. Heretofore range of such missiles has been controlled by trajectory angle, or by use of air-fric tion drag fines. Such methods of range control have certain disadvantages, among them, the degree or extent of range distance provided.
I find that by varying the amount of propellant charge in a rocket the range of the rocket is adjusted for all distances up to the maximum for which the rocket was built. Heretofore, variation in the amount of propellant charge has been accomplished by adding to or substracting from the charge prior to firing, or by manufacturing a series of rockets with specified propellant charges adjusted for predetermined distances. These latter methods have the disadvantages of lack of flexibility, undue multiplicity of stocks and inconvenience of adjustment. Furthermore, it is practically impossible to make changes in the amount of propellant charge in a missile at the time of use under rapid fire conditions.
An object of this invention is to provide a missile capable of adjustment as regards distance of flight. Another object is to provide a missile which can be easily and quickly adjusted as regards distance of flight even under rapid fire conditions. Still other objects and advantages of this invention will be realized upon reading the following specification and drawing, which repectively describes and illustrates preferred embodiments of my invention.
I accomplish these and other objects and advantages by providing a rocket having a uniform charge for all rockets of a given type, the charge being of such a nature that combustion is limited or regulated to a predetermined percentage of the total charge. A control means is provided which can be quickly and definitely adjusted for regulating the percentage of the charge to be fired thereby regulating the range of the rocket. This adjusting of a flight regulating mechanism can be carried out any time prior to the firing operation, preferably immediately before the missile is fired.
In the drawing, FIGURE 1 is a longitudinal view, partly in section, of one embodiment of apparatus of my invention.
FIGURE 2 is a perspective view of a portion of FIG- URE 1.
FIGURE 3 is a perspective view of an alternate embodiment of a portion of FIGURE 1.
, surface burning by known methods in such a manner that the burning of one segment will not ignite any other segpropellant segment begins to burn.
3,142,959 Patented Aug. 4, 1964 ment of propellant. Broadly speaking, a mechanism is provided for regulating the number of propellant segments to be burned during a given flight and by thus regulating the number of propellant segments to be burned, the range of the missile is determined.
In FIGURE 1 separate and individual propellant segments 12 are separated from each other by short distances and the entire assembly of propellant segments is housed within a conventional case 11. Reference numeral 13 identifies the exhaust nozzle of the case while 33 identifies the forward or leading end of the missile. In case the missile contains an explosive charge, it will be contained in this leading end 33. The propellant segments are covered with a layer of restrictive material 32 in such a manner as to eliminate free surfaces of solid propellant and thereby prevent the burning of the propellant segments at undesired surfaces. Each propellant segment is provided with an igniter 14 which preferably is an electrical igniter. Connected at one terminal of each igniter 14 is a separate wire 17. The wires 17 from the several igniters pass along the inner surface of the case 11 as a cable 18 toward the forward. end at which they are connected to a regulating mechanism. The other terminal of each igniter can, if desired, be grounded or, if desired, wires 17a can be connected, leading to a common wire or cable 19 which, in turn, leads toward the forward end of the missile. A source of electromotive force 20, such as a battery, is connected to wire 19 and grounded at 26 so as to provide electromotive force for energizing the igniters. In FIGURE 1 is illustrated, broadly, a range control mechanism 15 which is operated by adjusting a knob or pointer 21 to a number on a scale on the outer surface of the missile case, the numbers being the numbers corresponding to the propellant segments. For example, if it is desired to fire the missile for an in tended range of 5/7 of its maximum distance, knob or pointer 21 would be set to number 5 on the scale, thus causing 5 propellant segments of the rocket to burn successively thereby causing the rocket to travel 5/7 of its maximum distance.
FIGURE 2 illustrates, in some detail, a contact mechanism disposed inside the rocket case immediately under the pointer 21. This interior apparatus comprises a plate 16 having contact points numbered 1, 2, 3, 4, 5, 6 and 7, as illustrated. In FIGURE 3 is shown knob or pointer 21 for clarity reasons even though the pointer itself is actually outside the casing. A stop 22, also illustrated in FIGURE 3, is attached, as shown, to pointer 21 so that upon rotation of this pointer the stop also rotates. As illustrated in FIGURE 3, when pointer 21 is pointing at contact 5, stop 22 is approximately midway between contacts 5 and 6 in such a manner that a contact arm 23,
which is connected with a timer 27 illustrated in FIG URE 3, upon making electrical contact with contact 5,
cannot move to contact 6 because of the position of the stop 22. At the time of manufacture of this assembly, contact arm 23 is positioned on the side of contact point 1 opposite from contact point 2, so that contact is not made with any of the numbered contact points. Upon starting the mechanism, contact arm 23 starts rotation around the axis of knob 21 as the center in a manner similar to the hands of a clock. Contact arm 23 first makes electrical contact with contact point 1 at which time igniter 14 of the propellant segment nearest exhaust nozzle 13 is activated and this propellant segment starts to burn. The timer is so constructed that by the time the first propellant segment is consumed, the moving contact arm 23 makes electrical contact with contact point 2 and the second Thus, all five of the propellant segments burn in succession in a manner just described.
In FIGURE 3 is illustrated a push button switch 31 which completes an electrical circuit from a source of electromotive force, such as a battery 29, through switch 31 and wires 30 to the electrical clock timer 27, this circuit being grounded at 26a. The movable contact arm 23 rotates as the electrical timer operates thereby making successive contacts with the several contact points.
Contact point 1, FIGURE 3, is connected with igniter 14 of the first propellant segment through a wire 17 with the circuit being completed through the igniter, return Wire 19, source of electromotive force 20, such as a battery, and wire 25, to another terminal of the apparatus which, in this case, is a spindle upon which knob or pointer 21 is placed. Ground for this circuit is at 26.
The embodiments illustrated in FIGURES 1 and 3 comprise an electrical timer mechanism which is started, as mentioned hereinbefore, by pressing a push button starter switch 31.
In FIGURE 2 as illustrated, an electrical firing mechanism is regulated by a mechanical timer 27a. Mechanical timer 27a is powered by a turning key 24 in a keyhole 24a in a manner similar to winding an ordinary clock. Thus, upon giving key 24 a tumor two, the timing mechanism is started. In this embodiment wires leading to the several igniters 14 and a source of electromotive force for exciting the igniters are the same as illustrated in FIGURES 1 and 3. A plate which contains the several contact points 1 to 7, inclusive, is identified by reference numeral 16a. This plate contains the keyhole 24a through which the stem of winding key 24 extends. Contact 23 is grounded by way of a wire 25 to ground 26 with a circuit being completed through battery 20 and thence through wire 19 to the igniters.
In FIGURE 4 is illustrated a different type of control mechanism for regulation of the number of propellant segments to be burned during a given flight. In this embodiment the wires lead from a battery, not shown, to first igniter 14, that is, the igniter nearest nozzle 13 of the case, are the only ones connected to the battery. Other igniters 14 in succession are ignited by the burning of the previous propellant segment. Thus, in FIG- URE 4, as the propellant segment 12 nearest nozzle 13 nears the end of its burning, a fuse 42 is ignited and as the fuse burns toward igniter 14 of the next propellant segment, igniter 14, attached to this second propellant segment, is actuated and starts burning of this second propellant. Other and successive propellant segments are ignited in the same way. In order to control the number of propellant segments to be burned in a given flight, a heavy cord 41 is provided and extends through a small opening in case 11 and is tied around the fuse as illustrated. If, for example, it is desired to adjust the missile of FIGURE 4 for a flight distance equivalent to the burning of one propellant segment, the first cord 41 is then pulled mechanically and this pulling breaks fuse 42; and with this fuse 42 broken and pulled out of place, the second propellant segment cannot be ignited from the first. In this same manner the missile of FIGURE 4 can be adjusted for any flight distance merely by pulling the proper fuse cord and breaking the fuse following the last propellant segment desired to be burned.
In FIGURE is illustrated still another embodiment of control mechanism for regulating the flight distance of such a missile. This embodiment is somewhat similar to that illustrated in FIGURE 4 in that pull cords 51 are provided. In FIGURE 5, however, in place of merely breaking a fuse 55, a knife blade is attached to the inner end of the pull cords in such a manner that upon pulling a cord the knife cuts the fuse thereby rendering the fuse discontinuous. In this manner a fuse which is severed cannot excite the next successive igniter. In this figure wires 53 and 54 lead to a source of electromotive force for igniting the first igniter 14 while in FIGURE 4 wires 43 and 44 lead to a source of electromotive force for exciting the first igniter 14.
Therefore to control the range of a missile or rocket it 4 is merely necessary to determine the number of segments of solid propellant to be burned and then, as in FIGURE 1, merely adjust knob or pointer 21 to the proper contact, or, as in FIGURES 4 and 5, pull the proper cord to sever the fuse leading from one propellant segment to the next.
In place of numerals 1, 2, 3, etc., being stamped on the outer surface of case 11, if desired, the range of the missile corresponding to the propellant segments can be stamped on the case. Thus, if propellant segment 1 would propel the missile 1,000 yards, then 1,000 could be stamped in place of numeral 1. In like manner the rangedistance can be stamped on the outer surfaces of case 11 of FIGURES 4 and 5, corresponding to the particular pull cords. In order that pull cords 41 or 51 of FIGURES 4 and 5, respectively, are not inadvertently pulled, these cords can be taped or otherwise rendered inoperative until such time as it is desired to regulate the missile for flight. In case a tape such as an adhesive tape is employed, it is merely necessary to strip off the tape and pull the proper cord.
Any suitable solid propellant can be used in making up the propellant segment for use according to this invention. One suitable solid propellant is one containing ammonium nitrate as an oxidant and a rubbery material such as a copolymer of butadiene and a vinylpyridine or other substituted heterocyclic nitrogen base compound, which after incorporation is cured by a quaternization reaction or a vulcanization reaction. Such a solid propellant is fully disclosed in a copending application by Mahan and Hutchinson, Serial No. 561,944, filed January 27, 1956, now Patent No. 2,441,878.
A restricting material, that is, a material for restricting surface burning of solid propellant grains, is fully described in a copending application by Hayrnes et al., Serial No. 708,330, filed January 10, 1958, now Patent No. 2,995,091. e
A suitable restricting material, as disclosed in Serial No. 708,330, includes such materials as cellulose acetate, ethyl cellulose, butadiene-methyl vinylpyridine copolymer, .GR-S, rubbery compositions free from oxidizing agents and the like. These materials are sprayed on, brushed on or otherwise applied to the propellant surface to be restricted, and cured in case the composition is of a 'curable type. In case a restricting material is not of the curable type, such as methyl phenyl urea, it is dissolved in a solvent applied to the surface, and the solvent allowed to evaporate.
In reference to FIGURE 5, an alternate embodiment of the knife blade illustrated in the drawing is a large knife blade having a large surface area so that when the edge of the blade cuts the fuse, some portion of the blade remains between the severed ends as an ignition barrier.
While certain embodiments of the invention have been described for illustrative purposes, the invention obviously is not limited thereto.
"Dhat which is claimed is:
1. A rocket comprising, in combination, a plurality of solid propellant segments having their surfaces completely restricted against surface burning disposed serially along a common axis, said propellant segments being solid cylinders and having their longitudinal axes positioned along said common axis for successive burning, a case surrounding said segments, said case having a leading end as regards direction of travel and an exhaust nozzle at the other end, a separate igniter operatively 'positioned on and against the propellant on the side of each propellant segment facing said exhaust nozzle, means for exciting the igniter nearest said exhaust nozzle, and
means for regulating a predetermined number of said propellant segments to be burned. V
2. A rocket comprising, in combination, a plurality of solid propellant segments having their surfaces completely restricted against surface burning disposed serially along a common axis, said propellant segments being solid cylinders and having their longitudinal axes positioned along said common axis for successive burning, a case surrounding said segments, said case having a leading end as regards direction of travel and an exhaust nozzle at the other end, a separate igniter operatively positioned on and against the propellant on the side of each propellant segment facing said exhaust nozzle, a plurality of electrical circuits, each circuit of said plurality of circuits containing one each of said igniters, a source of electrical energy connected into said circuits, a timer, each circuit being in electrical communication with said timer, a timer stop, said timer being adapted to close a predetermined number of circuits beginning with the circuit containing the igniter closest to said exhaust nozzle, and said timer stop being adjustable to stop said timer after closing a predetermined number of said circuits.
3. The rocket of claim 2 wherein said timer is a mechanical timer.
4. The rocket of claim 2 wherein said timer is an electrical timer.
5. A rocket comprising, in combination, a plurality of solid propellant segments having their surfaces completely restricted against surface burning disposed serially along a common axis, said propellant segments being solid cylinders and having their longitudinal axes positioned along said common axis for successive burning, a case surrounding said segments, said case having a leading end as regards direction of travel and an exhaust nozzle at the other end, a separate igniter operatively positioned on and against the propellant on the side of each propellant segment facing said exhaust nozzle, a separate fuse connecting operatively each pro pellant segment with the igniter on the next successive propellant segment beginning with the propellant segment nearest said exhaust nozzle, and means for disconnecting each fuse from the propellant segment to which it is connected for burning only a predetermined number of propellant segments.
6. The rocket of claim 5 wherein said means is a separate cord attached to each fuse and extending through said case and each cord being adapted on manually pulling same at its outer extremity to rupture the fuse to which it is attached. I 7. The rocket of claim 5 wherein said means comprises a separate cutter positioned operatively to cut each fuse, a separate pull cord attached to each cutter and extend ing through said case, each pull cord being adapted on being pulled manually from the exterior of said case to move the cutter to which it is attached thereby severing a fuse.
8. In a rocket having a maximum range of travel, a system for regulating the distance of travel of said rocket for a predetermined distance up to said maximum range comprising, in combination, a plurality of solid cylindrical, solid propellant segments having their surfaces completely restricted against surface burning disposed serially along a common axis for successive burning, a case surrounding said segments, said case having a leading end as regards direction of travel and an exhaust nozzle at the other end, a separate igniter operatively positioned on and against the propellant on the side of each segment facing said exhaust nozzle, means for exciting each igniter in succession beginning with the igniter closest to said exhaust nozzle, and stop means for terminating successive excitations of said igniters at a predetermined propellant segment whereby only a predetermined number of propellant segments is ignited thereby regulating the travel distance of said rocket.
9. In a rocket having a maximum range of travel, a system for regulating the distance of travel of said rocket for a predetermined distance up to said maximum range comprising, in combination, a plurality of solid cylindrical, solid propellant segments having their surfaces completely restricted against surface burning disposed serially along a common axis for successive burning, a case surrounding said segments said case having a leading end as regards direction of travel and an exhaust nozzle at the other end, a separate igniter operatively positioned on and against the propellant on the side of each segment facing said exhaust nozzle, a separate electrical circuit communicating with each igniter for exciting same in succession beginning with the igniter closest to said exhaust nozzle, a timer for closing each circuit in said succession, an adjustable stop means, this latter means being adapted to be set to regulate operation of said timer to permit closing of a predetermined number of said circuits for excitation of said number of igniters for burning of said number of segments and to prevent closing of a number of said circuits equal to the number of propellant segments less said predetermined number of circuits, thereby failing to ignite the number of segments whose igniter circuits are not closed and thus regulating the distance of travel of said rocket.
References Cited in the file of this patent UNITED STATES PATENTS 1,191,299 Goodard July 18, 1916 2,114,214 Damblanc Apr. 12, 1938 2,856,851 Thomas Oct. 21, 1958 2,945,344 Hutchinson July 19, 1960 2,956,401 Kane Oct. 18, 1960 FOREIGN PATENTS 9,398 Great Britain June 27, 1888