US2484355A

US2484355A - Reaction motor with propellant charge mounted in it

Info

Publication number: US2484355A
Application number: US589795A
Authority: US
Inventors: John W Parsons
Original assignee: Aerojet Engineering Corp
Current assignee: Aerojet Rocketdyne Inc
Priority date: 1945-04-23
Filing date: 1945-04-23
Publication date: 1949-10-11
Anticipated expiration: 1966-10-11

Description

N 06f 11 1949. J. w. PARSONS 2,484,355

. REACTION MOTOR WITH PROPELLANT CHARGE MOUNTED IN IT INVENTOR. JoH/v W. PfoA/f Y @aww/@yu A TTORNE YS CL ll, 1949. J W PARSONS 2,484,355

GE MOUNTED IN IT REACTION MOTOR WITH PROPELLANT CHAR Filed April 23, 1945 3 Sheets-Sheet 2 umn" "www www INVENTOR.

ATTORNEYJ REACTION MOTOR WITH PROPELLANT CHARGE MOUNTED 1N IT Filed April 23, 1945 Oct. 11, 1949. J. w. PARSONS 3 Sheets-TSheOt 3 INVENTOR JOHN W PARSONS ATTORNEYS Patented oet. 11,1949 2,484,355

UNITED STATES PATENT OFFICE REACTION MOTOR WITH PROPELLAN T CHARGE MOUNTED IN IT John W. Parsons, Pasadena, Calif., assignor to Aerojet Engineering Corporation, Azusa, Calif., a corporation of Delaware Application April 23, 1945, Serial No. 589,795

14 Claims. (Cl. 60-35.6)

1 2 This invention relates to jet propulsion and description and accompanying drawings in more particularly to means for improving the which: burning rate of propellants used in jet motors. Fig. 1 is a cutaway View partly in cross sec- A jet motor usually comprises a tubular ring tion showing the pan charge installed inside of chamber, closed at one end and equipped at the 5 a jet motor; other end with an exhaust nozzle. The propel- Fig. 2 is a cross section view on line 2--2 of lant charge is placed or cast in the tubular firing Figure 1 taken at the end of the motor showing chamber and is ignited by some suitable device the pan in position; when the motor is to be placed in operation. The Fig. 3 is a perspective View of a pan, charge exhaust nozzle is preferably designed accordl and ignitor; ing to the De Laval type and the exhaust gases Fig. 4 is a partial view partly in cross section from the combustion of the propellant charge showing an alternative construction in which issue through the exhaust nozzle at high velocity two pans are employed instead of one; thereby creating thrust. The propellant charge Fig. 5 is a cross section View showing the two in the firing chamber of the motor may be either 16 pans in position in the shell; of the smoke-producing type or smokeless type. Fig. 6 is a view partly in cross section showing The smoke-producing type is usually compounded an alternative construction employing three pans; from a mixture of potassium perchlorate and Fig. 6a shows a modification of the arrangeasphalt while the smokeless variety may be comment of Fig. 6; pounded from a mixture of ammonium per- 20 Fig. 7 is a cross sectional View showing another ehlorate and asphalt, alternative embodiment employing four pans;

Although it would be desirable to employ Fig. '7a shows a modification of the arrangesmokeless propellants in many instances, the ap` ment of Fig. 7; plication of ammonium perchlorate type of pro- Fig 3 SilOWS e Cartridge type pl'pelleni Charge; pellants has been limited, due to the fact that and charges compounded from ammonium per- Fig. 9 shows a oros-s section through a portion chlorate and asphalt usually possess lower burnof the propellant charge, showing the thermoing rates than burning rates which may be atplastic and ilelie liner in DOSOH. tained with the potassium perchlorate type of Referring to the device illustrated in Fig. 1, e

propellant. As a res-ult the ammonium per- J'ei 11101301 i having a ling chamber 2 and an chlorate type has generally been satisfactory only eXheuSi nOZZle 3 and a safety Plug 4, Capable for operations where a low thrust is required over 0f releasing excessive pressure, is charged with longer periods of time than can be obtained from e DIOPeilaIli Charge 5 which is cast in a recthe potassium perchlorate type, tangular pan 6 having four sides and a bottom,

According to my invention I provide an arand the 130D Open t0 eXDOSe the prepelleni'. The rangement which increases the amount 0f pro.. surface of the propellant charge is crisscrossed pellant burned per unit time in a chamber 0f with a series of grooves I8 to assist burning. An

even size, and thereby permits the use of the end cover 1 is secured to the firing chamber 2 by slower burning smoke1ese propenants. I carry threads 8, these threads 8 permitting removal of out my improvement by the provision in the the end cover when a new propellant charge is chamber of one or more pans for holding the iJO be installed in the motor.

propellant, and arranged in the chamber so as .The plODelieni Charge Container iS constructed to provide a greater propellant burning surface t0 iii? snugly in the inside 0f firing Chamber 2 than would be had by merely casting the propel-. as shown in .Fig- 2- A bei' 9 iS` insieiled diametrilant in the chamber. By selecting the number 45 can? @cross the iing Chamber atposition l0, of pans and the extent of the exposed propellant Whlch 1S at the pony- Where the rmg @hamper Surfaces, I am able to adjust the amount of mm undergoes the transitlon between the cylindrical to the spherical, and is secured at this point in peuant burned per umt mme m the chamber as any suitable manner such as welding the bars may be desired et beth ends The eh arge 1s prevented from sl1d- Features of my mventlon relate to the S'hfap-e ing in the opposite direction toward the open and arrangement of the propellant Container end by securing it in position with a bracket Il palS- which is in turn secured to angles I2 which are The above and other features will be better diametrically fastened by any suitable means understood by referring to the following detailed 5 such as Welding to the ring chamber Wall. This 3 bracket is held in place by bolts I3 and rests` against a U-shaped member I4 fastened to the end of the propellant pan.

An ignitor I5, which in this embodiment is shown as a cylindrical tube, extends the entire length of the firing chamber and is secured to the charge by brackets I6. The ignitor charge is fired, preferably by electrical contact made through the hot Wires I1.

Figs. 4 and 5 show alternate embodiments of this invention in which the single pan 6 is substituted by a pair of pans I9 and 20, which are inserted in the jet motor back to back and are held together at the ends by bolts 2I passing through corresponding holes drilled in angle irons 22, which are attached to the pans in any suitable manner, preferably by welding. Since the two pans both have an exposed surface, each of which is of the same size as that of the single pan charge, this device Will burn twice as much propellant per unit time as will be burned by the single pan device. The assembled pans are held in position by a bar at the rear end similar to the bar 9 of Fig. 1 and at the front end by a strap member 24 which is attached to the firing chamber shell 2 by bolts 25 passing through angle irons 25, which are attached inside the shell of the firing chamber at the desired point by any suitable method, preferably welding.

Another alternative embodiment of my invention is shown in Fig. 6 in which a three pan construction is employed.

Pans

30, 3| and 32 are mounted in the motor chamber 2 in the manner shown in Fig. 6. The two

outside pans

30 and 32 have their exposed surfaces facing the firing chamber wall and the central pan 3I may open either way and ts into the space between

pans

32 and 30. The outside pans, which in the multiple pan type of apparatus ordinarily are placed so that the burning surfaces of the charges face the firing chamber wall, may be, if desired, reversed as shown in Fig. 6a, wherein the surfaces I0 and II are the burning surfaces Iwith the surfaces 'I0 and 'I6 facing each other; so that the burning surfaces of each pan faces the center of the unit and in this manner places the charges so that the burning surfaces face each other. This arrangement is more satisfactory in applications where it is preferable to have a greater open area above the burned surface of the propellant than would be available if the burning surfaces of the propellant charge face the motor walls. Pan 3| fits snugly in the maximum diameter of the motor of the firing chamber shell and is held in position by a bracket 33 which is attached at either end to angle irons 34 which are secured to the inside of the firing chamber shell by bolts 35. 'Ihe

pans

33 and 32 are supported by

shelf arrangements

35 and 31 and held securely against the firing chamber shell 2. These pans are also prevented from sliding in a longitudinal direction by brackets 38 lwhich are secured to angle irons 39 by bolts 4U.

Fig. 7 shows an embodiment in which four propellant charge pans are employed. The two central pans 50 and 5I are assembled similarly to the two pans used in Fig. 4 only differing from these in depth. Pans 50 and 5I are bolted together at the ends by `bolts 52 passing through corresponding holes in brackets 53. A number 54 prevents the pans from sliding in a longitudinal direction. This member is secured to the firing chamber shell 2 by bolting it to angle irons 55 with bolts 56.

Pans

51 and 58 are smaller in exposed area than the two `central pans 50 and 5I but of tle same depth. These pans are held in position by

shelf arrangements

59 and 60 and kept from sliding longitudinally by brackets 6l and 62 which are secured by bolts 63 to the angle irons 64 attached to the firing chamber shell. In all of the above multiple pan type of charges it is desirable that the depth of the propellant charge in each pair of pans be the same. This precaution is taken to insure a uniform thrust throughout the firing chamber at all times and to prevent an uneven thrust or deflection of the motor which would result if the charge on one side were consumed more rapidly than that on the other.

Fig. 7a shows a slight rearrangement of Fig. 7, in that the surfaces 'I2 and 'I3 are the burning surfaces and face inwardly toward each other and toward the respective burning surfaces 'I4 and 'I5 of the central charges.

The operation is as follows: A propellant, preferably of the smokeless type, is cast into the rectangular-shaped pan receptacle which is designed to t snugly inside of the firing chamber section of a jet motor having a removable end. The upper surface of the propellant7 which is exposed, is grooved by scratches I8 and supplied with an ignition charge which may be ignited by hot wires heated by electrical contact initiating combustion of the entire exposed area of the propellant. Since the exposed area determines the amount of propellant burned per unit time, the amount of thrust desired can be regulated by increasing or decreasing the size of this exposed area and in this manner a propellant charge may be made available that is suitable to meet a wide variety of thrust requirements. rlhis is better illustrated `by Fig. 4 which indicates an embodiment suitable for increasing the burning area to provide a greater thrust than could be achieved by the use of a single pan in the motor such as used in Fig. l. In all these devices the charge burns lengthwise over the entire exposed area which faces the side of the chamber. The ends are protected to prevent burning such as would occur if the charge were solidly cast in the chamber and ignited at the nozzle end.

A convenient manner in which the apparatus may be employed is as follows: The propellant, preferably of` the smokeless type, is lcast in rectangular-shaped molds corresponding to the shape of the pans employed in the apparatus, the casting is then extracted from the mold and dipped in a thermoplastic substance so that all surfaces are covered except the burning surface. The dipped charge is wrapped with a suitable tape liner and fireproofed to prevent burning on the outside surface of the charge. This is more clearly shown in Figs. 8 and 9 in which the thermoplastic charge 5 is surrounded by a thermoplastic coating 65 and taped across the bottom and sides in the manner shown by overlapping

layers

66 and 61 of a suitable tape material. The liner is then flreproofed and the cartridge casting is ready for insertion in the pans.

An advantage of my invention is that the device makes it possible to provide a greater burning surface than heretofore and thereby increase the amount of available thrust without resorting to extreme motor sizes.

Another advantage of my invention is that the .containers for the propellant charges are made cheaply and are easily available. The propellant may lbe easily cast, then shipped and stored until ready for use.

I claim:

1. A jet propulsion motor comprising a firing chamber having a longitudinal axis and an exhaust nozzle coaxial with the axis and located at an end of the chamber, a pan within said firing chamber, a propellant charge in said pan, the charge having a flat exposed surface substantially parallel with said axis and means for igniting the charge and means for holding said pan securely in position.

2. A jet propulsion motor comprising a firing chamber having a longitudinal axis and an exhaust nozzle coaxial with the axis and located at an end of the chamber, a plurality oi pans within said ring chamber, propellant charges in said pans, the charges having hat exposed surfaces substantially parallel with said axis and means fior holding the pans securely in position.

3. A jet propulsion motor comprising a ring chamber having a longitudinal axis and an exhaust nozzle coaxial with the axis and located at an end of the chamber, a plurality of pans within the firing chamber, propellant charges in the pans, the charges having fiat exposed surfaces substantially parallel with said axis, said pans being so placed that a space is provided between one pan and the next to permit free exhaust of products of combustion, and means for holding said pans securely in position.

4. A jet propulsion motor comprising a firing chamber having an exhaust nozzle, two pans of similar area and depth so proportioned that when the bottoms are placed against each other the pans fit in the ring chamber, propellant charges in said pans, and means for holding the pans securely in position.

5. A jet propulsion motor comprising a firing chamber having an exhaust nozzle, three pans so proportioned that they t in different levels of the firing chamber cross section, propellant charges in said pans, and means for holding the pans securely in position.

6. A jet `propulsion motor comprising a firing chamber having an exhaust nozzle, four pans so proportioned that they fit into the firing chamber at different levels, propellant charges in said pans, and means for holding the pans in position.

7. A jet propulsion motor comprising a firing ,chamber having an exhaust nozzle, three pans within said ring chamber, said pans being proportioned so that the two outside pans have a similar exposed area and depth, propellant charges in said pans, said three pans being so spaced that the products of combustion from each charge may easily exit between said pans and escape through the exhaust nozzle, and means for holding the pans securely in position.

8. A jet propulsion motor comprising a tubular firing cham-ber having a nozzle at one end, a pan in the chamber containing a propellant charge with an exposed burning surface, the pan being so placed that the burning surface of the propellant charge faces the tubular Wall of the chamber.

9. A jet propulsion motor comprising a tubular firing chamber having a nozzle at one end, two pans in the chamber each containing a propellant charge with an exposed burning surface, the burning surfaces of the propellant charges facing opposite sides of the tubular wall.

10. A jet propulsion motor comprising a tubular firing chamber having a nozzle at one end, three pans each containing a. solid propellant charge with an exposed burning surface, the pans being located in said chamber in such a manner that the burning surfaces of the charges are substantially parallel to each other, two said propellant surfaces facing one side of the tubular wall of the chamber and the other surface facing the opposite side of said tubular wall.

11. A jet propulsion motor comprising a ring chamber having a nozzle at one end, two pans in the chamber each containing a propellant charge with an exposed burning surface, the burning surfaces of the propellant charges facing each other.

12. A jet propulsion motor comprising a firing chamber having a nozzle at one end, four pans each .containing a solid propellant charge with an exposed burning surface, the pans being placed in such a manner that the burning surfaces of each pair of pans on each side of center face each other.

13. A jet propulsion motor comprising a firing chamber having a nozzle at one end, a pan placed so that the open side of the pan faces the wall of the chamber, a Vwrapped propellant cartridge placed in said pan, said wrapped cartridge being substantially the same in shape as the pan, and comprising a propellant charge, a thermoplastic liner covering said charge on all surfaces except the burning surface and a tape wrapping surrounding said thermoplastic liner.

14. In a jet propulsion motor the combination which comprises a ring chamber having a nozzle at one end, a pan disposed longitudinally in the -chamber and a propellant charge disposed in the pan, the pan and charge being so arranged that at least one side surface of the charge is exposed and flat and substantially parallel with the longitudinal axis of the chamber so that it burns toward the side of the chamber but the end surfaces of the charge are protected to prevent burning.

JOHN W. PARSONS.

REFERENCES CITED UNITED STATES PATENTS Name Date Mallory Nov. 8, 1881 Number