US2434298A - Jet reaction motor - Google Patents

Description

Jan. 13, 1948. R. c. rRuAx JET REACTION MOTOR Filed March 27, 1940 mvENToR ROBERT C. TPL/AX ATToRN Piuma .ha 13, 194s UNITED STATES PATENT, QFFICE (Granted under the act -oi' March 3, 1883, as amended April 30, 1928; 370 0. G. 757) 8 Claims.

This invention relates to an apparatus of the rocket, or jet reaction, type, intended for use as an auxiliary source of power for aircraft propulsion. which is especially valuable for use in take-offs, in increasing the pay load of ilying boats, and in giving a rapid initial rate of climb.

It is an object of this invention to produce such a unit which will produce a large thrust per pound of weight for short periods of time.

It is a further object of this invention to produce such a unit in a form which will be safe in operation, simple in construction, and inexpensive to manufacture and maintain.

It is a further object of this invention to provide a type of jet reaction motor capable of burning a mixture of liquid hydrocarbon and liquid oxidizer as a fuel.

It is another object of this invention to provide for emcient cooling of the walls of the combustion chamber and nozzle by utilizing as cooling agents only those substances otherwise necessary as fuel.

Other objects of the invention will become apparent from a careful consideration of the following description when taken together with the accompanying drawings, in which:

Fig. 1 is a side elevational view of the complete unit, with portions broken away;

Fig. 2 is a cross-sectional view taken along the longitudinal axis of the combustion chamber: and

. Fig. 3 is an end view of the combustion chamber looking toward the left in Fig. 2.

Fig. 4 is a cross-sectional view showing the details of valve 28' of Fig. 1.

Fig. 5 is a cross-section oi a portion of Fig. 1, taken at the plane 5-5 of Fig. 1 and looking toward the right.

The unit consists, in general of a jet reaction motor I and three tanks containing the fluid necessary for its operation. A liquid hydrocarbon such as gasoline is contained in tank 2 and a liquid oxidizer such as liquid oxygen in tank 3. In tank B is contained a charge of nitrogen which is used to force the fuel ingredients into the combustion chamber and cooling jackets of the motor.

Valve 5 is a combined starting and reducing valvel the starting element of which consists of a starting piston arrangement similar to that formed by the pistons I6 and I'I and cylinder I8 shown in Fig. 2, except that in valve 5 the larger piston is `perforated by a small hole which permits nitrogen to leak through and build up pressure on top of the piston, and throughthe vent line I9, to also admit this pressure to the top of piston I1. The underside of the starting piston communicates, by a vent through the valve body, to the nitrogen tank 4, and controls ports to the pipe 6 which leads the nitrogen at reduced pressure to tank 2 and to the vpipe 1 which leads it to tank 3 for pressurizing said tanks when valve 28 is opened to vent the line I9 to the atmosphere, reducing the pressure on top the starting piston, moving it outwardly and opening the ports to the pipes 6 and 1. Venting the line I9 also causes pistons I6, I'I to move to the left in response to fuel pressure in pipe II and starts the fuel injection.

The jet reaction motor I, as shown in Fig. 2, consists of a double walled combustion chamber 8 in which combustion of the fuel takes place and a double walled nozzle 9 in which the products of combustion are expanded and discharged to the atmosphere.

The hydrocarbon fuel is led from tank 2 through pipe I0 to the inner end of the jacket surrounding the nozzle 9. As it traverses the interior of the jacket it .cools the inner wall of the nozzle and is heated for the purpose of increasing its elciency as a constituent of the fuel mixture.

From the outer end of the jacket it is led through i pipe I I to the opposite end I2 of the rocket motor. Here it enters the combustion chamber 8 by Way of a bore I3, a spiral atomizer I4 and a nozzle I5.

Prior to the starting of the motor the bore I3 `is normally blocked by the presence of the piston I6. Concentric to and integral with piston I6 is a larger piston II which moves through cylinder I8. A pipe I9 leads from cylinder I8 to the reducing and starting valve 5, and normally causes the outer face of piston I'I to be subjected to the nitrogen tank pressure, thus maintaining bore I3 blocled against the entry of hydrocarbon through line I.

The operation of the piston I'I is controlled by a conventional stop and vent valve 28' in pipe I9. This valve is shown in Figure 1 and in detail in Fig. 4, and will normally be located in the cockpit of Athe airplane. As shown in Fig. 4, when valve 28' is screwed down to its seat the top of valve 5 is in communication with the top of cylinder I8, but when valve 28' is unseated these spaces are placed in open communication withI the atmosphere by means of the vent 34 in the bottom of valve 28. By its operation, the nitrogen pressure which has built up on top of piston I'I in cylinder I8 and on top of the starting piston in the reducing valve body 6, by leakage through the hole in the latter piston, is released. The pressure on the under side of the starting piston opens the ports to the pipes 6 and l controlled by valve 5, permitting the nitrogen to ilow to the reducing valve which may consist of restricted passages in the body of valve 5. As the nitrogen pressure is transmitted through pipe 6 to the hydrocarbon in tank 2, the pressure thus built up opens the valve formed by piston i6, allowing the flow of hydrocarbon into the combustion chamber.

The combustion chamber is double walled to provide a cooling jacket 29. Between the double walls a spiral vane 20 forms a spiral passageway for the liquid oxidizer which thus ac ts to cool the inner wall of the combustion chamber and at the same time is vaporized to increase its efilciency as a constituent of the fuel mixture.

The liquid oxidizer enters the jacket of the combustion chamber through pipe 2l which has its intake end 22 located near the bottom of tank 3. It traverses the spiral passageway 29 formed by vane 20 until it reaches the intake end of the combustion chamber which it enters through the annular opening 23. At this point it becomes mixed with the atomized hydrocarbon and burns. A portion of the gases of combustion is tapped from the combustion chamber by pipe 24 through which it is led into tank 3 and thence through a continuation of the same pipe, now numbered 25, into an annular chamber 26 near the throat of the nozzle 9. From this chamber it enters the nozzle at the throat through annular opening 21 which is so directed as to cause the cooled gases to form a protecting and cooling blanket for the inner wall of the nozzle. The gases of combustion flowing through the portion of pipe 24 which passes through tank 3, serve to preheat the liquid in the tank before the liquid goes to the combustion chamber jacket and the gases are themselves cooled to add to their eirlciency as a cooling medium for the nozzle.

The fuel mixture is ignited by means of a slowburning fusee 28 which can be set off by remote control. Once started, combustion of the fuel continues without assistance.

When used as an aid to take-oil the unit is intended for only a single continuous operation. The units may be so mounted as to be capable of being dropped from the aircraft when exhausted.

By utilizing the wall cooling means of this invention, combustion chamber and nozzle walls of steel or similar metals will withstand long periods of use, whereas without such cooling means even the most refractory of materials will last but a few seconds under the terrine heat generated in the motor.

A unit such as described herein will develop a thrust of 10,000 lbs. for a period of 30 seconds, or smaller thrusts over longer periods of time.

This invention affords an inexpensive, efiicient, simple, and handy means for furnishing auxiliary power for aircraft, exceeding in these respects any catapult, pick-a-back or air refueling system ever devised. The motor is also safe in operation and handling and presents no extensive problems in maintenance.

While the disclosure of this application has been limited to one embodiment of the invention, the scope of the invention is to be considered as restricted only by the scope and limitations of the appended claims.

The invention described herein may be manufactured and/or used by or for the Government of the United States of America for governmental purposes without the payment of any royalties thereon or therefor.

Iclaim:

1. In a power producing device, a jet reaction motor comprising a combustion chamber terminating in a nozzle, a source of fluid fuel under pressure, a jacket formed about said nozzle, means leading said fuel into said jacket where it acts to cool the walls of said nozzle. means leading said fuel from said jacket into said combustion chamber for burning, means bleeding oil a Portion of the gases of combustion from said chamber, heat recovery means for cooling said gases and means directing said cooled gases along the inside surface of the walls of said nozzle.

2. In a power producing device, a jet reaction motor comprising a combustion chamber terminating in a nozzle, means for tapping off a portion of the products of combustion from said Combustion chamber, means for cooling said tapped oil gases comprising a heat exchanger which simultaneously preheats one of the elements comprising part of the combustible mixture, means for leading said cooled gases into the interior of said nozzle and means for directing said cooled gases along4 the inner surface of said nozzle in the form of a protective blanket.

3. In a power producing device, a jet reaction motor comprising a combustion chamber terminating in a nozzle, a source of oxidizing material at a sub-atmospheric temperature, means for tapping olf a portion of the gases of combustion from said combustion chamber, means leading said portion of said gases into heat exchanging relation with said oxidizing material, thereby cooling said portion of said gases and preheating said oxidizing material, means for leading said cooled gases into the interior of said nozzle and means for directing said cooled gases along the inner surface of said nozzle in the form of a protective layer.

4. In a power producing device, a jet reaction motor comprising a combustion chamber terminating in a nozzle, a jacket formed about said combustion chamber, a jacket formed about said nozzle,v a source of iiuid fuel under pressure, means leading said fuel into said nozzle jacket and thence into said combustion chamber, a source of fluid oxidizing material at a sub-atmos- Dheric temperature, means leading said oxidizing material under pressure into said combustion chamber jacket and thence into said combustion chamber, means mixing said fuel and said oxidizing material in said combustion chamber for burning, means tapping off a portion of the gases of combustion from said combustion chamber, leading said tapped off portion outside said chamber and into heat exchanging relation with said oxidizing material and thence into the interior of said nozzle, and means for directing said cooled gases along the inner surface of said nozzle in the form of a protective layer.

5. In a power producing device, a jet reaction motor comprising, a cylinder forming a combustion chamber and provided with means for the admission of fuel gases thereto, an exhaust nozzle formed on the cylinder, an annular chamber surrounding said nozzle, a supply tank for oxidizing material normally at a sub-atmospheric temperature, a pipe connected with said combustion chamber for tapping of! hot combustion gases therefrom and passing through said supply tank, in order to cool the combustion gases in said pipe and preheat the oxidizing material, said pipe containing the now cooled combustion gases being connected with the annular chamber surrounding said nozzle for the purpose of cooling same, a second discharge nozzle connected with the firstnamed nozzle, forming in conjunction with said annular chamber an annular throat adapted to direct the cooledgas therefrom along the inner surface ofsaid second nozzle in the form of a protective layer for said surface against the hot discharge gases which come direct from the combustion chamber of the device.

6. In a power producing device, a jet reaction motor comprising. a cylinder forming a combustion chamber and provided with a controllable inlet orice for admission of fuel-gases thereto, a combustion chamber discharge nozzle having an annular chamber surrounding same, a second discharge nozzle in alignment with said first nozzle, a jacket formed about said second nozzle, an oxidizing gas jacket formed around said combustion chamber, a tank for fluid fuel under pressure, 2

means leading said fuel into the Jacket surround-y ing said second nozzle and thence through the inlet orifice and into said combustion chamber, a supply tank for oxidizing material normally at a sub-atmospheric temperature, a pipe leading the oxidizing material under pressure into said combustion chamber jacket and thence to and through said inlet orifice into the combustion chamber, means for mixing said fuel and oxidizing material for burning preparatory to its introduction into the combustion chamber, a pipe connected with the combustion chamber for tapping oif a portion of the hot combustion gases therefrom and passing them through the oxidizing material supply tank. and thence leading into the interior of the annular chamber surroundl ing said first nozzle, and means for directing the bustion chamber and provided with a controllable inlet orifice for admission of fuel gases thereto, a combustion chamber nozzle, having an annular chamber surrounding same, an end discharge nozzleadjacent 'to said cylinder nozzle, a jacket formed about said discharge nozzle, an oxidizing gas jacket formed around said combustion chamber, a continuous vane mounted in the oxidizing gas jacketiormlng a helical passageway for the oxidizing gas, a pressurized fuel-supply tank,l

means delivering fuel fromv said tank into said end discharge nozzle Jacket, and thence through said inlet orifice and into said combustion chamber, a supply tank for oxidizing material at a subatmospheric temperature, a pipe leading the cold oxidizing material under pressure into said oxidizing gas jacket for the purpose of cooling the walls of said combustion chamber and raising the temperature'of the oxidizing material as it .passes through the oiddfzing material tank, and thence leading into the interior of said annular chamber around the combustion chamber nozzle, and means for directing the cooled combustion gases from the said annular chamber along theinner surface of said end discharge nozzle in the form of a protective layer of comparatively cool gases, surrounding the much hotter gases of combustion which come directly from thecombustion chamber of the` device.

8. In a power producing device, a jet reaction motor comprising a combustion chamber terminating in a nozzle, a jacket formed about said combustion chamber, a jacket formed about said nozzle, a source of fluid fuel under pressure, means leading said fuel into said nozzle jacket and thence into said combustion chamber, a source of uid oxidizing material at a sub-atmospheric temperature, means leading said oxidizing material under pressure into said combustion chamber jacket, a continuous vane mounted in the oxidizing gas jacket forming a helical passageway for the oxidizing material for the purpose of cooling the walls of the combustion chamber .and raising the temperature of the oxidizing material as it passes along said helical passageway, and means thereafter leading the material into the combustion chamber, means for mixing the fuel and oxidizing material for burning in the combustion chamber, means tapping on a portion of the gases o1' combustion from said combustion chamber, leading said tapped off portion outside said chamber and into heat exchanging relation with the oxidizing material and thence along the inner surface of said nozzle in the form of a' pro- A tective layer.

- REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS o'rHER REFERENCES 'Ihe Rocket Motor" in Astronautics. Mar. 1936, pages 12-14.

The Rocket Combustion Motor, byllugen` Sanger, in Astronautics. Oct. 1936, pages 10-11.

ROBERT c. TRUAX.

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