US2792758A - Reaction device - Google Patents

Description

May 21, 1957 JfH. BACH ETAL REACTION DEVICE Filed Nov. 8, 1954 Qmw Sv REACTION DEVICE John H. Bach and Vaughn E. Peak, Hawthorne, and Karl W. Maier, Torrance, Calif., assignors to Northrop Airraft, Inc., Hawthorne, Calif., a corporation of Caliorma Application November 8, 1954, Serial No. 467,332

15 Claims. (Cl. 89-1.7)

Our invention relates generally to reaction devices, and more particularly to a solid fuel reaction motor which is highly eicient for short duration applications such as in spin launching rockets and the like.

One specific example wherein the device of our invention is singularly useful is in the spin launching of rockets. The term rocket as used herein for purposes of illustratng one application of our invention, is intended to include both guided and unguided self-propelled reactiondriven missiles.

By way of explanation; when any elongated missile is propelled lengthwise 'through the air, it has an inherent tendency to tumble, i. e., instead of proceeding along its trajectory with its longitudinal axis parallel with the line of ight, this axis may rotate erratically with respect to that line of ilight. To reduce this tendency of a missile to tumble, and improve its stability over the flight trajectory, a means and method of spin launching, and spin stabilizing a rocket during ight, is described, shown, and claimed in co-pending U. S. patent applications: Serial No. 425,594, tiled April 26, 1954, by Edgar Schmued et al., and Serial No. 425,595, also tiled April 26, 1954, by Edgar Schmued, wherein initial stabilizing spin is imparted to a rocket in the launching tube or bed during launching thereof so that the rocket will leave the launcher in a spinning condition, thereby providing gyroscopic stabilization of the longitudinal axis of the rocket upon entering the initial acceleration phase of its flight trajectory. To this end, it is an object of our present invention to provide a spin motor of the solid fuel type having improved eiciency for short duration applications.

It is another object of our invention to provide a solid fuel type reaction device which can be adapted for spin launching rockets.

It is still another object of our invention to provide a spin motor for spin launching rockets, which can be quickly and easily recharged.

It is a still further object of our invention to provide a spin motor in which a charge of solid fuel is uniquely arranged in such a manner as to obtain optimum combustion efficiency.

Other objects will be readily seen as the specification proceeds.

Briefly, in one preferred embodiment thereof, as applied to spin launching a rocket, the spin motor of our invention comprises a spin motor body adapted to be coupled with a rocket to be spin launched, a solid fuel charge supported and arranged in the spin motor body in such a manner as to insure a high degree of combustion efficiency, and an ignition system coordinated to ignite the spin motor charge and the rocket propellant in proper sequence.

The principle, character, and preferred construction of our invention will be more clearly understood by referring to the appended drawings wherein:

Figure 1 is a side elevational View, partly in section and partly fragmentary, showing one preferred embodi- 21,792,758 Patented May 21, 1957 ment of our present invention coupled to a rocket in a launching tube.

Figure 2 is a cross section View taken on line 2 2 of Figure 1 showing one novel means of suspension and arrangement of the solid fuel in the spin motor of our invention.

Figure 3 is a plan view of the brush assembly for igniting the propellant charge indicated by arrow 4 in Figure 1, the housing being cut away to show a preferred arrangement of the brushes.

Figure 4 is a perspective view of the rocket and spin motor of the previous gures, with certain portions cut away to more clearly show the preferred construction and arrangement of our present invention.

In Figure l a rocket 7 to be spin launched is shown positioned in a rocket launching tube 9. The rocket 7 is provided with a rearwardly disposed combustion chamber 10 containing a propulsion charge 11 arranged in the usual manner; the gas from the propulsion charge 11, when ignited, being released through a number of nozzles 12 arranged and mounted at the rear end of the rocket to propel the rocket forward.

In accordance with our invention, the rocket 7 is initially spun, before being propelled from the launching tube 9, by means of a spin motor assembly 14 which is mounted in the launching tube 9 rearwardly of the rocket 7 as shown.

The spin motor assembly 14 of our invention generally includes coupling means for connecting the rocket and spin motor together, an exhaust or blast tube for carrying off the rocket propulsion charge gases, spin motor ignition assembly, and spin motor, all of which will be identified and described in detail herein. In the present example, the coupling means is characterized by a number of conventional key slots 15 evenly spaced around the circumference of flange 16 at the rear end of rocket 7 as best shown in Figure 4; these slots 15 complementing and receiving a like number of keys 17 which are provided around the edge of the ared end 19 of a blast tube 20 which extends coaxially through spin motor 21 and is coterminous therewith. The flared end 19 of blast tube 20, when coupled with rocket 7, by keys 17 and key slots 15, completely surrounds and encloses the rocket nozzles 12 and thus ducts the released propulsion gases through blast tube 20 and out the exit opening 22 as the spin motor drives the rocket 7 to rotate prior to launching.

Spin motor 21 is rotatably mounted in the launching tube 9, and comprises a cylindrical body 24 enclosing a combustion chamber 25 which concentrically surrounds the exterior blast tube 20. At the exhaust end of spin motor body 24, a flange 26 is formed normal to the axis of the body 24, and a shallow land 27 precedes the ange 26; another land 27a of the same diameter being provided at the coupling end of motor body 24 to provide bearing surfaces therefor.

Flange 26 extends beyond the end edge 29 of launching tube 9 to prevent forward movement of the spin motor in the tube 9. The exterior circumference of the launching tube 9 is threaded to receive a retaining ring 30 and exhaust shield 31; the motor 21 being thereby prevented from axial movement in the tube 9.

The exhaust end of spin motor body 24 and combustion chamber 25 is enclosed by a nozzle plate 32, the plate 32 being retained in position by threaded portions 34 around the exterior of blast tube opening 22 and central opening 35 of nozzle plate 32. Spaced around the inner face of nozzle plate 32 are a number of exhaust ports 36 which are Ainterconnected with a number of tangentially directed exhaust nozzles 37 on the rear face of the nozzle plate 32. It is preferred that the interior ports 36 be sealed by frangible or rupturable seals 39, of foamedV plastic or other suitable material in the usual manner, for the obvious reason of preventing the entry of moisture or foreign matter thereinto.

In the combustion chamber 25, at the driving or coupling end of spin motor body 24, an ignition charge 40` is formed in an annular ring around blast tube 2Q and is sealed with a conventional fragibl'e seal 41. A primer pellet 42 embedded in the ignition charge is, in the present example, red by electrical current conducted from a source thereof (not shown), such as a battery for example, through brush assembly 44y which is'enclosed in a housing 45 mounted on the exterior periphery of launching tube 9, as best seen in Figures l and 3. Y Y

The ignition of the spin motorcharge and toeliet propellant charge is achieved by contacting b/rlllshesl 46l and 47, respectively, with the exposed edgesfof annular tiring slipk rings 49 and 50 which are, in the present example, insulated by and embedded in a support member. 5.1A preferablyy molded of a dielectric material Asuch as alphenolic resin or neoprene rubber for example, and mounted in launching tube 9 adjacent'to Vtheforvvarif'lY end of spin motor body 24. inside the blast tube 20, support meinber 51 is encased in a protective heat resisting 'sheath 52, of a metal such as that used to. nzlakefthe blast tube 20, and forms a narrow streamlined bipodal member to reduce the amount of wind resistance thereby in the ared throat of blast tube 20 as much aspossible'l Of the two leg elements S4 and 54a of support member 51,o`ne. element 54a encloses an insulated lead: 56VV connected at one end thereof to tiring slipv ring 50; they other end terminating in a pin 57 which is inserted in an electrical jack 59. housed in the rear end of rocket 7. As shown in Figures l and 4, support member 51l extends forwardly from its base to form a probe 60 which encloses andy insulates, rocket propellant lead wire 56. Over the` endv of probe 60, a sleeve 61 is tted to underlap thevsheath 52 and terminates at the forward end inV a button 62 having a detent groove 64 cut around the periphery thereoffV The exhaust end of rocket 7 has a. coaxial receptacle 66 therein to recess button 62 adjacent electrical jack 59. An annularv internal groove 67 extending around the inner periphery of receptacle 66 retainsl a split ring 69 which, when button 62 is recessed in4 receptacle 66, tits down into and around detent groove 6 4 to vhold the button 6'2- in place and retain pin 57 in electrical engagement withy jack 59. However, the button 62 may bewi'thdrawn from receptacle 66 and pin 57 disengaged from electrical jack 59 by force exerted longitudinally, either by movement of the rocket 7 forwardlyin the tube 9, as when launched, or by withdrawing the spin motor assembly'21 rearwardly fromV the4 tube 9 suchV as during servicel and installation operations, for example. As shown, the wall. 70 of the detent groove 64 nearest the end of button 62 is sloped forwardly to cam the split ring 69out of the detent groove 6.4.'for release of the firing mechanism. The. outer end 71 of button 62 is also sloped, rearwardly from the outer end thereof, so thatthe split, ring 69 iscammed thereover when recessing the button 62,in the receptacle` 66` to connect electrical pin 57 and electrical jack 59, when the rocketV and spin motor arecoupled together.

In alignmentV with electrical pin 57, and retained in the opposite end of receptacle 66, is the jack 59. It will be noted that electrical jacl 59 is embedded in dielectric plastic and insulated` from surrounding structure by insulator sleeves 74.

An insulated lead, 75 isconnected, at one end thereof, in jack 59, the otherend,thereofextending coaxially and forwardly through rocket combustion chamber 1010 propulsion charge primer pellet 77 and connects into primer cap`79., to ignite rocket lpropulsion charge 1v1 in the usual manner. Ground lead 81 is [connected *to the metal primer casing. d2l at. one end thereof; the other end being connected` to the metal sleeve74 around the lead jack 59, andy thus completes the electrical circuit for firing the rocket propulsion charge.r

It can be Seen that-the-Operatisn of cartulina of. the

' argan@ ring circuit of the rocket 7 with the spin motor 21 is simply and quickly achieved at the same time that the rocket 7 is installedy in the launching tube 9 and moved into engagement with drive key slots 15 and 17 in mesh; the electrical connection being made when button 62 is fully recessed in rocket receptacle 66 with split ring 69 securely seated in annular detentV groove' 67 to electrically connect pin 57 in jack- 59.

Rocket propellant ignition wire 7,5 conducts electrical current from tiring slip ring 50. which malges continuous Contact with brush 47 extended through aligned apertures 84 in the bottom of housing 45 and though the Wall of launching tube 7, while the motor is spinning.V

The diameters of ring slip rings 49 and 50 should be suiciently smaller thank thek inside diameter of launching tube 9 so that an appreciable clearance space 85 is maintained between the contact or exposed edge of the rings 49 and 5 0 and the launching tube wall.

Brush 46, for firingl the spin motor 21 is maintained in` contact with the edge of tiring slip ring 49 by a leaf spring 86 mounted in brush housing 45 in the usual manner. Rocket tiring brush 46, in the same manner as brush 47, is` extended through apertures 87 to contact ring slip ring 49, which is connected by insulated lead` 89 to primer pellet 90, and ground brush 9 1 is contacted withy spin motor land 27g.

To improve the burning characteristics of the spin` motor fuel charge, and obtain the highest practicalr order of eiciency therefrom, we arrange the fuel in` such a manner as to provide a small web thickness in india'idual grains andl therefore obtain a high ratio of initial com.- bustion area to volumeof charge.

As shown in Figures land 2, the fuel for spin motor 21 isY uniquely formed into tubular pellets or grains 95, in any convenient manner, and cut into desired lengths. These grains 95, after further forming, can then be strung, or assembled, onto support wire-s4 (not shown) formed into. individual rings or coils and thusbe supported thereby in thecombustion chamber 25` with all surfaces exposed to initial combustion. The curved support wires, furthermore, expose the end surfaces of the tubular grains, thereby increasing the initial combustion area. of the fuel. In the particular embodiment of Figure l, however, annealed wire 97 of. suitable gage is helically wound into a, support for the tubular grains. of fuel. assembled thereon, and extends through the combustion chamber 25, being maintained in a, position concentricV with the. axis of spin motor body 24 and. blast tube 20. The diameter of the. fuel'grainsr95' is sized so that an appreciabieclearance between the wall of spin. motor. body 244l and blast tube 20 is uniformly maintained from one endV of combustion chambery 25 to the other.

Therearmost endl of the support wire 97 is suitably formed and anchored aroundthe periphery of blast tube 20, being secured between circumferential ange 99 and the inner edge. of nozzle plate 37. For. easeof installing and reloading the fuel charge, they ignition charge 40y is preferably retained in a light metal casing 100, the other end of supportwire 97, suitably formed, being-connected to the ignition charge casing by edge rolling 101 around primer casing asshown.

While we have illustrated the helical support wirev 97 as being ixedat-either end in the combustion chamber-25, the, support wire 97 could be freewheeling, with both ends` free, which would to. some degreek tend to reduce centrifugal stresses on` the fuel grains. However, it has been` found that, with the ends ofthe support wire 97 securely fastened toV xed supports, the response of the support wire to rotation is so rapid that the individual coils will differonly slightly` with respect to relative position thereof during motion. However, in a fuel arrangement as describedy above wherein theV tubular fuel grains are supported on individual; rings of Wire, it is believed that 11o` appreciable diirenceia the effect o f the centrifugal stresses on the fuel grains would be encountered.

In the general fuel arrangement illustrated in the instant disclosure, a number of distinct advantages will be noted by those skilled in the art. The relative proportions of the fuel grains and diameter of the combustion chamber, which will be governed by the usual parameters, can be adjusted to achieve the highest possible combustion eliiciency therefrom.

Moreover, it has been found that the fuel grains, arranged and supported in accordance with our present invention, have a much greater resistance to breakaup than in prior known configurations and arrangements. It is further believed that the helical arrangement, due to its asymmetr' will not induce the phenomena of extremely high peak pressures which are usually observed in symmetrical arrangements of fuel grains.

` While in order to comply with the statute, the invention has been described in language more or less specific as to structural features, it is to be understood that the invention is not limited to the specific features shown, but that the means and construction herein disclosed comprises a preferred form of putting the invention into effect, and the invention is therefore claimed in any of its forms or modifications within the legitimate and valid scope of the appended claims.

What is claimed is:

l. In a reaction device including a combustion chamber having a quantity of solid fuel therein; a fuel support comprising a plurality of Wire rings coaxially positioned along the extent of said combustion chamber, said fuel being concentrically formed around and supported by said rings.

2. In a reaction device including a combustion chamber having a quantity of solid fuel therein; a fuel support comprising a helical coil coaxially mounted in said combustion chamber, said fuel being concentrically formed around said helical coil and suspended thereby in said combustion chamber.

3. In a reaction device including a combustion chamber having a quantity of solid fuel therein; a fuel support comprising a helical coil of wire coaxially mounted in said combustion chamber, said fuel being tubularly formed and strung onto said coil and suspended thereon in said combustion chamber.

4. In combination with a rocket launching tube and a rocket in said tube, said rocket having a propulsion charge; means for spinning said rocket about the axis thereof prior to ignition of said propellant comprising a cylindrical motor body mounted to rotate about an `axis i in said launching tube, separable coupling means connecting one end of said motor body to the exhaust end of said rocket, a combustion chamber in said motor body, a quantity of propellant grains in said combustion chamber, support means for suspending said propellant 'grains in said Ycombustion .chamber to expose a maximum area of initial burning surfaces of said propellant grains, ignition means for igniting said propellant, tangentially directed exhaust means for releasing combustion gases from said combustion chamber to rotate said motor body, means for igniting said rocket propulsion charge during rotation of said motor body, and means for bypassing propulsion gases from said rocket through said motor body and out of said launching tube.

5. Apparatus in accordance with claim 4 wherein said propellant grains in said combustion chamber are tubularly shaped, and wherein said support means comprises a plurality of wire rings coaxially and concentrically positioned in said combustion chamber, said tubular propellant grains bein-g strung onto said rings and suspended thereby to expose a maximum area of initial burning surface on said propellant grains.

6. Apparatus in accordance with claim 4 wherein said propellant grains in said combustion chamber are formed into curved tubes, and wherein said support means com.-

prises a coil of helically wound Wire coaxially and con# centrically positioned in said combustion chamber and extended from one end of said combustion chamber to the other end thereof, said tubular propellant grains being strung onto said wire and suspended intermediate the wall of said duct and said motor body to expose a maximum area of initial burning surface on said propellant grains.

7. In combination with a rocket launching tube and a rocket iin said tube, said rocket having a propulsion charge; means for spinning said rocket about the longitudinal axis -thereof prior to the ignition of said propulsion charge comprising a cylindrical motor body mounted 4to rotate about an axis in said launching tube, separable coupling means connecting one end of said motor body to the exhaust end of said rocket, a duct extending coaxially through said motor body, one end of said duct being open opposite the exhaust end of said rocket, the other end of said duct being open opposite the exhaust end of said launching tube, a combustion chamber in said motor body and surrounding said duct, a plurality of propellant grains in said combustion chamber, support means for suspending said propellant grains in said combustion chamber intermediate said duct and the wall of said motor body to expose a maximum area of initial burning surfaces thereof, means for igniting said propellant grains, tangentially directed exhaust means connected with said combustion chamber to release combustion gases therefrom to rotate said motor body, and means for igniting said rocket propulsion charge after said motor body has begun to rotate.

8. In combination with a rocket launching tube and a rocket therein, said rocket having a propulsion charge and exhaust nozzles for releasing gases from said propulsion charge to propel said rocket; means for spinning said rocket around the longitudinal axis thereof prior to launching, which comprises a cylindrical spin motor body mounted to spin about an axis in said launching tube adjacent the exhaust end of said rocket, a blast tube extending coaxially through said motor body, one end of said blast tube being flared to extend around and enclose said rocket exhaust nozzles, the other end of said blast tube being open adjacent the exhaust end of said launching tube, separable coupling means connecting said motor body to said rocket, an annular combustion chamber in said motor body and concentrically surrounding said blast tube, a plurality of tubular propellant grains in said combustion chamber, ra helically Wound support wire coaxially positioned in said combustion chamber and concentric with the wall of said motor body and said blast tube, said tubular propellant grains being strung onto said support wire to expose a maximum area of initial burning surface thereon, ignition means for igniting said motor propellant grains, a plurality of tangentially directed exhaust nozzles positioned around said blast tube and communicating with said combustion chamber to direct combustion gases therefrom to spin said motor body, and ignition means for igniting said rocket propellant charge while said rocket is being spun, whereby said rocket is propelled from said launching tube in a spinning condition.

9. Apparatus `in accordance with claim 8 wherein said separable coupling means comprises a plurality of members mounted around said ared end of said blast tube, and a plurality of members mounted on said rocket around the exhaust end thereof, said members interlocking with each other to couple said rocket with said spin motor body.

10. Apparatus in accordance with claim 9 wherein said friction means is a plurality of teeth on said rocket and extending around said rocket exhaust nozzles, and where in said flared end of said blast tube has a plurality of complementary teeth extending therearound meshing with said teeth on said rocket to couple said rocket with said spin motor body.

ll. In combination with a rocket launching tube and a rocket therein to be launched therefrom, said rocket having a propulsion charge and exhaust nozzles for releasing gasesmfrorn said propulsion eharge to propel said rocket mea-ns for spinning said rocket around the longitudinal axis thereof prior to launching, which comprises a cylindrical spin motor bodymounted to spin about an axis in said launching tube adjacent the exhaust end of said rocket, a blast tube extending coaxially through said motor body, one end of said' blast tube being ilared to enclose said rocket nozzles, coupling means on `said rock-et and extending around said rocket nozzles, coupling means extending around said ilaredend 0f said blast tube and di'sengageably coupled with said coupling means on said rocket, an, annu-lar combustion chamber in said motor body and concentrically surrounding said blast tube, a pluralityV of tubular propellant grains in said combustion chamber,I a helicallyl wound' support wire coaxially positionedf in said combustion chamber and concentric with the wallY of said motor body *and said blast tube, said tubular propellant grains being, strung onto said support wirel t o expose a maximum area of initial burning surface thereon, a primer in said spin motor combustion chamber adjacent said propellant grains, a primer in said rocket adjacent said propulsion charge., ignition means operable to ignite said spin motor propellant primer, and ignition means operable while `said spin motor is spinning to ignite said rocket propulsion charge to thereby launch said rocket in a spinning condition.

l2. Apparatus in accordance with claim l1 wherein said ignition means for igniting said spin motor propellant primer and said ignition means for igniting said rocket propulso'n charge comprise a firstl c-ontact member conducting electrical currentffrom a source thereof to re said spin motor propellant primer, a second contact member conductingelectr-ical current from a sourcethere'- of to fire said rocketl propulsion charge while said spin motor and said rocket are spinning, and a groundl contact to said spin motor body and interconnecting Isaid rocket propulsion charge primer and ignition means therefor, and saidV rocket propulsion charge and ignition4 means therefor;

13.` Apparatus in, accordance with claim 11 wherein said ignition means comprises a sheathed, dielectric 'support mounted. in saidY blast` tube adjacent the ared end thereof, said support member extending through the wall of saidg blast tube and having thebase thereof joining the end' of spin motor body adjacentthe exhaust end of said rocket, the other end, of said. support member extending into thev endy of, said rocket and terminating in ay disengageable rocket receptacle, therein, a first annular conductor embedded iny said support member base and coaxial; with launching, tube. said conductor having al1 edge thereof exposed around the exteriory periphery ofy said support member base,v an electrical connection embedded in said supportV member connecting said conductor to said spin motorpropellant primer, a brush contact extended through the wall' of said launching tube and inv contact with said annular conductor to conduct aow of electrical current from a sou-ree thereof to re said spin motor propellant primer, a second annular conductor embedded in lsaid support member base adjacent said rst annular conductor and coaxial with said launching tube, said second conductor having an edge thereof exposed around the exterior periphery of said support member base, an electrical connection embedded in said support member and connected at one end thereof to said annular conductor, the other end thereof terminating in a plug jack in said rocket receptacle, said rocket receptacle being electrically connected to said rocket propulsion charge primer, a second brush contact extending through the wall of said launching tube and in contact with said second annular conductor to conduct a tlow of electrical current from a source thereof to tire said rocket propulsion charge primer while said rocket is spun by said spin motor, thereby to launch said rocket in a spinning condition.

14. In a device of the character described; a fixed cyl inder, a cylindrical motor body mounted to rotate about an axis within said fixed cylinder, means dening a corn-V bustion chamber in said motor body, the interior Surface of `said cylindrical motor body forming the wall of said combustion chamber, a plurality of tubular propellant grains in said combustion chamber, a plurality of wire rings coaxiallyl positioned along the extent of said com* bustion chamber, said propellant grains being strung onto said wire rings and supported thereby between said axis of rotation and the wall of said combustion chamber to expose a maximum area of initial burning surfaces thereon, ignition means for igniting said propellant grains, and tangentially directed exhaust means connected with said combustion chamber to release combustion gases therefrom to rotate said motor body.

15. In a -device of the character described; a fixed cylinder, a cylindrical motor body mounted to rotate about an axis within said iixed cylinder, a combustion chamber in said motor body, a plurality of curved tubular propellant grains, a helical coil of wire extending coaxially through said combustion chamber, said propellant grains being strung onto said coil and suspended thereby in said combustion chamber toexpose a maximum area of initial burning surfaces thereon, ignition means for igniting said propellant grains, and tangentially directed exhaust means. connected with said combustion chamber to release gases therefrom to rotate saidmotor body.

Referencesv Cited4 in the'. tile of this patent UNITED STATESl PATENTS 2,342,096 Zimmerman Feb. 1,5, 1944 Y 2,510,110 Hickman June 6, 1950 2,510,147 Skinner June 6, 1950 2,640,417 Bjork etal. June 2,l 1953 FOREIGN PATENTS 2,497` GreatBritain` s of 185,8

116,430 Sweden May 2,1, 1946 120,158

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