US3073113A

US3073113A - Propulsion apparatus

Info

Publication number: US3073113A
Application number: US844700A
Authority: US
Inventors: Harold F Faught
Original assignee: Westinghouse Electric Corp
Current assignee: CBS Corp
Priority date: 1959-10-06
Filing date: 1959-10-06
Publication date: 1963-01-15
Anticipated expiration: 1980-01-15

Description

Jan. 15, 1963 H. F. FAUGHT PROPULSION APPARATUS Filed Oct. 6, 1959 HIGH "PRESSURE nvzm' GAS 26 cuzcx VALVE FIG.8. .5 n

INVENTOR HAROLD F. FAUGHT 3,073,113 PROPUIEJGN APPARATUS Harold F. Faught, Kansas City, Kane, assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Filed Oct. 6, 1%), Ser. No. 844,700 Claims. (Cl. 60--35.6)

This invention relates to rockets energized by combustion products of solid propellants andhas for an object to provide a rocket of this type having increased versatility in operation.

Rockets energized by combustion products of solid pro. pellants have heretofore been subject to the serious limitations of uncontrollable propulsive thrust level, since once the propellant charge has been ignited, the rate of combustion cannot be controlled. Although the rate of combustion is primarily dependent upon the chemical composition and consistencyof the fuel and oxidizer comprising the solid propellant charge, radical and unpredictable variations in the rate of combustion can also occur due to surface defects or cracks in the charge.

One of the main objects of this invention is to provide a. rocket having a solid propellant charge in which the propulsive thrust may be controlled during operation.

Another object is to provide a rocket of the above type in which combustion of the solid charge may be terminated and re-initiated at will.

A further object is to provide a solid propellant charge for a rocket, which charge mechanically combines the fuel and oxidizer elements.

Briefly, in accordance with the invention, there is provided a rocket having an outer casing including a forwardly directed nose portion and a rearwardly directed exhaust nozzleand having a chamber formed therein for burning ited States atent propellant to provide products of combustion which are subsequently ejected through the exhaust nozzle in a jet to provide a propulsive thrust to the rocket. Within the casing there is disposed a solid propellant charge extending longitudinally of the casing and mechanism for cornminuting the solid propellant into small particles which are directed into the chamber and ignited therein by suitable ignition means. The comminuting mechanism includes a comminuting member disposed in abutment with the end portion of the charge adjacent the chamber and supported for rotation by a shaft extending through the longitudinal axis of the charge.- The shaft is rotatable at variable speeds, as desired by a suitable variable speed motor. Further, the comminuting member and the charge are axially movable relative to each other, so that as comminution of the propellant is effected with subsequent shortening of the charge, separation between the comminuting member and the charge is obviated.

The propellant charge may be of any suitable type well known in the art comprising solid fuel material and solid oxidizer material chemically combined so that, as comminution is elfected, the comminuted particles include the optimum mixture of fuel and oxidizer for suitable combustion in the chamber. However, with the invention, the propellant charge need not be of the above type and may be formed of separate fuel andoxidizer elements of finite form, mechanically combined and havthe oxidizer elements and the fuel elements are concommitantly comminuted to provide the desired mixture for varying the rate at which comminution of the charge is.

3,@73,ll3 Patented Jan. 15, 1963 ice eifected. Such control is attained by varying the speed of the variable speed motor as desired.

To initiate operation of the rocket, the comminuting mechanism is first energized, thereby comminuting the expedient of increasing the rotary speed of the comminuting member by the driving motor. Conversely, the propulsive thrust may be reduced by reducing the speed of the comminuting member. I

Also, should it be desired to interrupt production of the gaseous products, such interruption may be attained by deenergizing the driving motor and terminating the comminut'ion of the charge.

The aboveand other objectsare effected by theinvention as will be apparent from the following description and claims taken in connection with the accompanying drawing forming a part of this application, in which:

FIG. 1 is an axial sectional view showing, in highly diagrammatic form, a rocket incorporating the invention;

FIGS. 2 and 3 are transverse sections taken on lines IL-II and IIIIII respectively of FIG. 1;

1, but showing a further embodiment of the invention.

Referring to the drawing in detail,.in FIG; 1 there is shown a jet propelled rocket 14) having an elongated tubular casing 11 formed-with a forwardly directed, aerodynamically faired nose portion 12 and a rearwardly directed exhaust nozzle 13. The casing 11 further defines a combustion chamber14disposed immediately upstream of the exhaust nozzle 13 and in fluid communication therewith.

A solid propellant charge 15 is snugly received within the casing lland extends from thecombustion chamber 14 to the nose portion 12. The cross-sectional shape of the casing 11 and of the charge 15 is substantially circular and, in this embodiment, the charge 15 is rigidly secured, in any suitable manner, to the casing and/ or a bulkhead 16 attached to the casing, to prevent rotation and longi tudinal movement relative to the casing. .T he charge 15, as illustrated in this embodiment, may be of any suitable type well known in the art and is formed of solid fuel material and solid oxidizer material mixed or chemically combined to provide a generally homogeneous charge, and is provided with an axial bore 17 extending therethrough. The rearward end portion 18 of the charge is .disposed adjacent the chamber 14 and a comminuting member Jl9.is disposed in abutment therewith and rotatably supported by. a shaft 20 extending through the-bore 17. The shaft 20 is connected to a variable speed motor 21, supported by the bulkhead 16 and disposed in the nose portion 12,.a considerable distance from the chamber 14 and a relatively cool region. The shaft, 20 is keyed to the comminuting member 19 by a key member 22 provided on the comminuting member and received in an elongated slot23 formed in the shaft and disposed parallel to the longitudinal axis of the shaft. The rearward end of the shaft may be rotatably supported by a bushing 24 supported in an'axialpiston by a plurality of radial struts 25 (only one shown) connected to the casing.

In operation, the motor 21 is energized by any suitable means (not shown), thereby rotating the shaft 20 and the comminuting member 19. Since the comminuting member 19 is disposed in contact with the end portion 18 of the solid charge 15, the comminuting member effects comminution of the solid charge into small particles which are directed into the combustion chamber 14. As such able pattern to insure full and uninterrupted comminution of the end portion 18 ofthe charge. As the length of the i charge is progressively shortened by such comminution,

the comminuting member v19 is maintained in constant abutment therewith by the pressure ofthe gaseous products. of combustion generated in the chamber 14 and is translated forwardlyalong the shaft 20, as permitted by theslot 23, until the comminuting member attains the end of its travel and abuts the bulkhead 16, at which time substantially the entire propellant charge has been consumed.

During operation, the thrust of the rocket may be varied as desired or controlled at a preselected value by varying the speed of the variable speed motor 21. That is, the thrust may be increased by increasing the rate of comminution of the charge 15, such increase being attained by increasing the speedof thecomminuting member. Conversely, the thrust may be reduced by reducing the rate of comminutionof the charge by reducing the speed of the comminuting member 19.

Further, if. desired, the thrust of the rocket may be interrupted at will by deenergizing the motor 21 and may be re-initiated, when desired, by reenergizing the motor and energizing the ignitors 26 to initiate combustion of the comminuted particles.

The comminuting member 19 is rotatable in a plane normal to the longitudinal axis of the charge 15. Accordingly, in accordance with the invention, the charge 15 is susceptible of various modifications consistent with simplicity and ease of manufacture as well as reduction in cost.

As illustrated in FIG. 4, there is-shown a solid propel lant charge '30 of modified'form comprising a solid fuel element or portion 31 and a solid oxidizer element or portion 32 disposed in physical abutment with each other and having cross sections of complementary shape jointly defining the circular cross-sectional shape of the charge. In

this embodiment, the fuel element 31 and the oxidizer element 32 are each of semi-cyclindrical shape and extend coextensively in longitudinal axial direction. The fuel element 31 may be one of the metallic fuels such as alu-' minum, magnesium or beryllium. The oxidizer may be of such materials as sodium perchlorate, potassium perchlorate, potassium nitrate, or sodium nitrate in either chemical or mechanical combination with a suitable binder. Accordingly, the'resulting comminuted particles formed by thecomminuting member 19will be a mixture of fuel noted that the centralangle, and thus the surface area, of

the fuel elements 34 is smaller than the central angle, and

i the surface area, of the oxidizer elements 35, so that dury'i'ng comminution a major portion of the comminuted mixture is oxidizer. However there, may be instances wherein.the mixture may desirably consist of equal parts by volume of oxidizer and fuel, or even circumstances in which it may be desirable to have a larger volumetric proportion of fuel than oxidizer in the comminuted mixture.

In FIGS. 6 and 7, there is shown another embodiment of the invention. Since most of the structure may be similar to that shown and described in conjunction with FIG. 1, these elements need not be described and will be referred to by the same reference numerals utilized in connection with FIG. 1. In this embodiment, a comminuting member 37 is rigidly attached to a rotatable drive shaft 38 extending centrally through the solid propellant charge 15 and rotatably supported at its forward end by a guide sleeve 39 secured to the nose portion 12. The motor 21 is supported within the nose portion 12 in an off-center position and is drivingly connected to the shaft 38 by a gear train 40 including a driving pinion 41 and a driven gear 42. The drive shaft 38 is longitudinally splined to provide a pair of longitudinal slots 43 and the bore of the gear 42 is provided with a pair of projections 44, as best shown in FIG. 7, slidably received in the slots 43. l i t ,5

In operation, the propulsive thrust is initiated in substantially the same manner as described in connection with the embodiment in FIG.- 1 by energizing the motor 21, thereby causing the shaft 38 to drive the comminut ing member 37. In this embodiment, the comminuting member 37 is also maintained in biased abutment with the propellant charge by the pressure of the gaseous products of combustion formed in the chamber 14. As the length of the charge 15 is progressively decreased by comminution, the comminuting member 37 is translated in forward direction with a following action to continue the comminution of the charge, such movement being permitted by the slots 43 and projections 44. During such translation, the forward end of the shaft 38 is translated forwardly through the opening 46 in the guide sleeve 39- In FIG. 8, there is shown a further modification whereinv the solid propellant charge 15 is slidably received in the casing 11 and has its forward end disposed in abutment with a piston member 47 slidably received in the casing 11. The piston member 47 forms a circular rear wall defining a forwardly disposed chamber 48 with the casing 11. The nose portion 12 is provided with a suitable ball check valve 49 through which high pressure gas, preferably of the inert type, isadmitted to' the chamber 48 to pressurize the same. With this arrangement, the gas pressure in the chamber 48 exerts a biasing effect on the piston 47 to the left, thereby to retain the rearward end of the charge 15 in abutment with a comminuting member 50. The comminuting member 50 is rigidly attached to a drive shaft 51 which extends through a bore 52 in the piston member 47 to'the driving motor 21. It is desirable that the piston member 47 be formed to provide a sliding gas tight seal with the interior surprovided with a tubular liner member 53 fixed to the casring 11 in any suitable manner.

The liner member 53 may be made of ceramic or suitable high temperature resistant metallic materials. In operation, the liner 53 becomes highly heated by the combustion process and is effective to heat the comminuted particles as they leave 5 the comminuting member, thereby promoting continuous combustion of the particles. I

It will now be seen that the invention provides a highly improved jet propelled rocket utilizing a solid propellant charge which is highly versatile in operation and in which the propulsive thrust may be varied as desired or controlled to provide consistent or uniform thrust by varying the rate at which comminu'tion of the solid charge is eifected.

It will further .be seen that with the invention, the solid propellant charge may be formed of separate fuel and oxidizer elements mechanically joined and shaped to provide any fuel and oxidizer mixture desired, thereby effecting economies in the manufacture of the charge.

Although the specific control mechanism for regulating the variable speed motor 21 has not been shown and forms no part of the invention, it will be obvious that the speed otthe motor may be regulated bysuitable mechanism responsive to the various operating conditions of the rocket, as well known in the art.

Although several embodiments of the invention have been shown, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various other changes and modifications without departing from the spirit thereof.

What is claimed is:

1. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rear-* wardly directed exhaust nozzle, means defining a propellant combustion chamber communicating with said exhaust nozzle, a solid propellant charge disposed in said casing, a rotary member for comminuting said charge, means for rotating said member, and means associated with said combustion chamber for igniting the comminuted particles of said charge.

2. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardly directed exhaust nozzle, said casing having a propellant combustion chamber disposed therein and communicating with said exhaust nozzle, a solid propellant charge disposed in said casing, said charge having an end portion disposed adjacent said combustion chamber, means disposed in juxtaposition with said end portion for comminuting said charge, means for rotating said comminuting means, means for continuously maintaining said comminuting means in contact with said end portion during rotation, and means associated with said chamber for igniting the co-mminuted particles of said charge.

3. In combination, a rocket comprising an outer casing having a rcarwardly directed exhaust nozzle and a propellant combustion chamber communicating with said exhaust nozzle; a solid propellant charge of cylindrical cross section disposed in said casing and having an end portion disposed in juxtaposition with said combustion chamber; a mechanism for comminuting said solid charge, said mechanism including a comminuting member disposed in juxtaposition with said end portion, a rotatable shaft for driving said comminuting member and extending through said charge, and a variable speed motor for driving said shaft; and an ignitor associated with said combustion chamber for igniting the comminuted particles of said charge.

4. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardly directed exhaust nozzle, a propellant combustion chamber formed in said casing and communicating with said exhaust nozzle, a solid propellant charge disposed in said casing, means for comminuting said charge, a

variable speed motor for driving said comminuting means, and means associated with said chamber for igniting the ccmminuted particles of said charge, said exhaust nozzle being effective to discharge the products of combustion of said particles in a propulsive jet.

5. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardly directed exhaust nozzle, said casing having apropellant combustion chamber disposed therein and communicating with said exhaust nozzle, a solid propellant charge slidably disposed in said casing, said charge having an end portion disposed adjacent said combustion chamber, comminuting means disposed in juxtaposition with said end portion, a variable speed 'motor'for driving said comminuting means, the end portionof said'charge being biased against said comminuting means during a drivingperiod, and means associated with said chamber for igniting the comminuted particles of'sa'id charge to provide gaseous products of combustion, said exhaust nozzle being efiec'tive to discharge theproducts of combustion in a propulsive jet. i

6. In combination, arocket comprising an outer casing having a forwardly directed nose portion, a 'rearwardly directed exhaust nozzle and a propellant combustion chamber communicating with said exhaust nozzle; a solid propellant charge of cylindrical shape fixedly disposed in said casing and having a circular end portion disposed adjacent said combustion chamber; a mechanism for comminuting said solid charge, said mechanism including a comminuting member disposed in juxtaposition with said end portion, a rotatable shaft for driving said comminuting member and extending through the longitudinal axis of said charge, and a variable speed motor for driving said shaft, said shaft being axially movable and maintaining said comminuting member in contact with said end portion during operation; and an ignitor associated with said combustion chamber for igniting the comminuted particles of said charge to provide gaseous products of combustion, said exhaust nozzle being effective to discharge the products of combustion in a propulsive jet.

7. In combination, a rocket comprising an outer casing having a forwardly directed nose portion, a rearwardly directed exhaust nozzle and a propellant combustion chamber communicating with said exhaust nozzle; a solid propellant charge of cylindrical shape fixedly disposedin said casing and having a circular end portion disposed adjacent said combustion chamber; a mechanism for comminuting said solid charge, said mechanism including a comminuting member disposed in juxtaposition with said end portion, a rotatable shaft for driving said comminuting member and extending through the longitudinal axis of said charge, a variable speed motor for driving said shaft; and an ignitor associated with said combustion chamber for igniting the comminuted particles of said charge; said shaft and said comminuting member being jointly rotatable but axially movable relative to each other.

8. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardly directed exhaust nozzle, means defining a propellant combustion chamber communicating with said exhaust nozzle, a solid propellant charge disposed in said casing, a rotary member for comminuting said charge, means for rotating said member, and means associated with said combustion chamber for igniting the comminutcd particles of said charge, said charge being of generally circular cross-sectional shape and having a solid fuel element and a solid oxidizer element extending coextensively and having complementary cross-sectional shapes jointly defining said circular cross-sectional shape.

9. In combination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardly directed exhaust nozzle, means defining a propellant combustion chamber communicating with said exhaust nozzle, a'solid propellant charge disposed in said casing, a rotary member for comminuting said charge, means for rotating said member, and means associated with said combustion chamber for igniting the comminuted particles of said charge, said charge being of generally solid cylindrical shape andhaving a circular cross section and a longitudinal axis and comprising a solid fuel element and a solid oxidizer element, said elements being disposedin mutual abutment and extending coextensively ingaxial direction and said elements having complementary; cross-sectionalshapes jointly definingsaid circular cross section.

10. Incombination, a rocket comprising an outer casing having a forwardly directed nose portion and a rearwardlydirected exhaust nozz1e',-means defining a propellant combustion chamber communicating with said exhaust nozzle, asolid propellant charge disposed in said casing, a rotary member for comminuting said charge,

means for rotating said membenand means associated with said combustion, chamber for igniting the comminuted particles of said charge, said charge being of generally solid cylindrical shape and having a circular cross section and a longitudinal, axis and comprising a solid fuel element. and a solid oxidizer element, said elements being disposed in mutual abutmentand extending co- '8 extensively in a direction substantially parallel to said axis, said elements being sector-shaped in cross section and jointly defining said circular cross section.

References Cited in the file of this patent UNITED STATES PATENTS 1 OTHER REFERENCES Publication, Optimum Proportioning of Two Propellants to Obtain Maximum Burnt Velocity, ARS Journal, vol. 29, No. 8, August 1959, pages 598 and 599.

Claims

8. IN COMBINATION, A ROCKET COMPRISING AN OUTER CASING HAVING A FORWARDLY DIRECTED NOSE PORTION AND A REARWARDLY DIRECTED EXHAUST NOZZLE, MEANS DEFINING A PROPELLANT COMBUSTION CHAMBER COMMUNICATING WITH SAID EXHAUST NOZZLE, A SOLID PROPELLANT CHARGE DISPOSED IN SAID CASING, A ROTARY MEMBER FOR COMMUNICATING SAID CHARGE, MEANS FOR ROTATING SAID MEMBER, AND MEANS ASSOCIATED WITH SAID COMBUSTION CHAMBER FOR IGNITING THE COMMINUTED PARTICLES OF SAID CHARGE, SAID CHARGE BEING OF GENERALLY CIRCULAR CROSS-SECTIONAL SHAPE AND HAVING A SOLID FUEL ELEMENT AND A SOLID OXIDIZER ELEMENT EXTENDING COEXTENSIVELY AND HAVING COMPLEMENTARY CROSS-SECTIONAL SHAPES JOINTLY DEFINING SAID CIRCULAR CROSS-SECTIONAL SHAPE.