US2523378A - Wing-mounted jet reaction engine for aircraft - Google Patents

Description

Sept. 26, 1950 P. KOLLSMAN WING-MOUNTED JET REACTION ENGINE FOR AIRCRAFT 2 Sheets-Sheet 1 Filed Nov. 28, 1945 INVENTOR.

PAUL 1(0LLSMAN ATTORNEY Sept. 26, 1950 P. KOLLSMAN WING-MOUNTED JET REACTION ENGINE FOR AIRCRAFT Filed Nov. 28, 1945 2 Sheets-Sheet 2 I N V EN TOR. PA UL 1f OLLS'MAM M n'r'roRA/E Y,

Patented Sept. 26, 1950 WING-MOUNTED JET REACTION ENGINE FOR AIRCRAFT Paul Kollsman, New York, N. Y.

Application November 28, 1945, Serial No. 631,363

3 Claims.

This invention relates to devices for producing a reactive thrust by pressure fluid discharged at substantial velocities and pressure from a discharge port and has particular application to duct-engines comprising basically a combustion chamber and an adjoining discharge duct through which slugs of pressure fluid are moved by explosions taking place in the combustion chamber.

The efficiency of engines furnishing fluid under pressure for producing reactive thrust depends on the rate ofspeed at which the pressure fluid is discharged. Under the most favorable operating conditions the rate of discharge of the pressure fiuid is equal to or sli htly greater than the speed at which the engine moves with respect to the surrounding medium, for example, the surrounding air, into which the discharge jet is directed. If the rate of discharge of the pressure fluid is considerably greater than the speed of the engine, a substantial loss of energy is incurred, generally referred to as loss due to slip. Duct engines or other pressure fluid generators generally produce slugs of pressure fluid travelling at too high a rate for efficient operation. It .is therefore desirable to reduce the rate to a figure .at which efficient operation is obtained.

It is further desirable to eject a constant flow of pressure fluid from a propulsion nozzle or port :rather than individual slugs or bursts in order to obtain a substantially constant propulsion force and to reduce the noise incident to the discharge of individual slugs.

The invention provides means for reducing the rate of speed of slugs of pressure fluid in engines of the above character to a, figure at which the pressure fluid is most advantageously discharged and provides in addition means for storing the volume of pressure fluid contained in the plu- .rality of slugs in order to produce a continuous even flow of fluid of equalized pressure adapted :to be discharged from a reaction port or nozzle under the most favorable condition.

The objects, features and advantages Of this invention will appear more fully from the detailed description which follows accompanied by drawings showing for the purpose of illustration preferred embodiments of the invention.

The invention also consists in certain new and original features of construction and combination of parts hereinafter set forth and claimed.

Although the characteristic features of the invention which are believed to be novel will be particularly pointed out in theclaims appended hereto, the invention itself, its objects and advantages, and the manner in which it may be carried out may be better understood by referring to the following description taken in connection with the accompanying partially diagrammatic drawings forming a part thereof, in which:

Fig. l is a longitudinal section of a duct-engine embodying the invention;

Fig. 2 is a longitudinal section of a portion. of a pressure fluid generator embodying the.- invention; I

Fig. 3 is a cross section taken on line 33 of, Fig. 2;

Fig. 4 is a longitudinal section of a multiple duct engine embodying the invention;

Fig. 5 is a section taken on line 5-5 of Fig. 4;:

Fig. 6 is a section taken on line 56 of Fig; 4; and

Fig. 7 is a section taken on line l'l of Fig. 4.

In the following description and in the claims various details will be identified by specific names for convenience. The names, however, are intended to be as generic in their application as the art will permit. In the specification the term pressure fluid or fluid is used as a generic term comprising both gases and liquid, or, in other words, media of compressible as Well as non-compressible character.

Like reference characters refer to like parts in the several figures of th drawings. In the drawings accompanying, and forming part of, this specification, certain specific disclosure of" the invention is made for the purpose of eX-l planation of broader aspects of the invention, but it is understood that the details may be, modified in various respects without departure, from the principles of the invention and that the invention may be applied to other structures; than the ones specifically shown.

The duct engine shown in Fig. 1 comprises a. combustion chamber H provided with a fuel in-. jector nozzle l2 supplied with fuel through a line, [3. Automatic inlet valves I4 admit a combus-; tion supporting compressible fluid into the come bustion chamber at suitable intervals where it mixes with the fuel injected by the nozzle [2 to form an explosive mixture. The combustion supporting fluid may be supplied to the inlet valves from a suitable source, not shown, and may 7 be precompressed gas or air admitted through the valves from a supply chamber surrounding or adjoining the outside wall or walls of the combustion chamber H, as shown, for example, in Figure 4, hereinafter described. These details are omitted from the drawing for the sake of clarity. Suflice it to say that the inlet valves 14 automatically operate to admit combustion supporting fluid to the combustion chamber previous to an explosion therein and that the valves automatically close when the pressure inside the combustion chamberexceeds the pressure outside.

The explosive charges in the combustion cham her are ignited by a spark plug l5 supplied with electrical energy from a suitable source not shown through a supply lead It.

fluid may be discharged from the chamber The discharge port may be coaxially arranged chamber [3 and to close when the pressure in the.

chamber it exceeds that in the duct I! to prevent a back flow of fluid from the chamber l8 into the duct H.

The chamber l8 has a discharge port 22 in one of the walls through which a jet of pressulrae with respect to the duct i! as at 22 or may be provided in the side wall at any desired location.

The walls 24 of the enlarged chamber I8 imimediately adjoining the end of the duct ll gradually enlarge in diameter, without abrupt changes,

energy of to permit transformation of kinetic :slugs of pressure fluid entering the chamber into pressure without causing energy consuming.tur-' .bulence,

The operation of the engine shown in Fig. 1 is as follows: After an explosive charge has been :formed in the combustion chamber l l the charge is ignited. The explosion causes a slug of pres- :sure fluid to move through the duct H at high velocity towards the enlarged chamber and the (discharge nozzle 22. The pressure of the slug causes the check valve l9 to open, admitting the slug of pressure fluid into the enlarged chamber.

A return or back flow of pressure fluid from the chamber l8 into the duct H is prevented by the check valve l9 which closes as soon as the pressure in the duct ll drops below the pressure in the chamber ill. The tapered walls 24 of the chamber l8 causes a reduction of the rate of travel of the slug while simultaneously permitting an increase in pressure.

The discharge of successive slugs of pressure fluid into the chamber I8 builds up a volume of fluid of high pressure therein. The velocity of the pressure fluid inside the enlarged chamber 18 is relatively lowwhile its pressure is high.

Pressure fluid inside the chamber i8 is continuously discharged through the discharge port 22 in the form of one continuous jet passing through the nozzle at a velocity lower than the average velocity of the individual slugs in the duct [1. The discharge velocity depends on the size of the discharge port or orifice 22; the frequency at which A I. This is evident that by suitable dimensioning :and timing a predetermined rate of discharge of :the pressure fluid can be obtained at the nozzle :22 which is most favorable for the condition :under which the device is to operate.

Fig; 2 illustrates an application of the invention toa pressure fluid generator providedwith means :for introducing a volume of a second pressure :fluid, such as air, between individual slugs passing through the duct of the generator. The duct 25 through which individual slugs of pressure fluid pass from the generator (not shown) leads to an enlarged valve housing'26 having a plurality of relief ports 2'! controlled by valve flaps 28. Pres- :sure fluid entering from the outside through the relief ports 21 enters chambers 29 in the valve lhousing 2'6 and thence pass into a continuation duct 30 containing a check valve 3!. The check valve 3| admits pressure fluid from the continua tion duct 36 into an enlarged chamber 32 having a discharge port 33. The walls 34 of the chamber gradually diverge to permit gradual reduction of the speed at which the gas goes into the chamber 31 from the continuation duct 50 while simultaneously permitting transformation of kinetic energy of the gas into pressure.

The device shown in Fig. 2 operates substantially as follows: Individual slugs of pressure fluid passing through the duct 25 at relatively high speed tend to lower the pressure in the space behind them which, in turn, causes a reduction in the rate of travel of the slugs and a loss. To prevent such reduction in pressure and in order simultaneously to increase the total volume of pressure fluid traveling through the. continuation duct, additional pressure fluid is admitted through the relief valves 21, 28 after each slug. The valve flaps 28 of the relief valves open automatically to admit pressure fluid from the space surrounding the valve housing 28, for example, air, when the pressure inside the valve housing drops to a predetermined point after passing of each slug.

of pressure, reduction of speed and transformation of energy takes place as described in connection with the engine shown in Fig. 1. Return of fluid from the chamber 32 into the continuation duct 3!! is prevented by'the check valve 3!. A continuous jet of pressure fluid is discharged through the nozzle of port 33 and furnishes motive power by reactive thrust,

A multiple duct-engine embodying the present invention is shown in Figs. to 7. Within the structure of an airplane wing 35 having a top surface 36 and a bottom surface 3'5 two duct-engines are mounted, one engine being visible in Fig. 4. Each engine comprises a combustion chamber H from which a duct il leads into a chamber 38, of gradually increasing cross section common to both ducts having a discharge port 39 in the bottom surface of the airfoil near its trailing edge it. Check valves 3i may be provided in each duct ii.

The combustion chamber is equipped with a fuel injector nozzle l2, automatic inlet valves i4 and a spark plug 25 similar to the engine shown in Fig. l. The ignition in the two combustion chambers is preferably so timed that explosions take place alternately. I

t the end of the combustion chamber i l proper, or at the end of the combustion area of the chamber 5 i, relief ports 41 are provided in the wall of the chamber or of the duct I! controlled by check valve flaps 32. Air is admitted through the inlet valve i i and the relief ports'M from a supply chamber 4'13 in the leading portions of the airfoil, the supply chamber formed by the top and bottom surfaces and the leading edge surface 44 of the airfoil and a back wall 45 in the interior of the airfoil. Air is admitted into the supply chamber 43 through a suitable port '35 which may be located in the leading edge at 4% or elsewhere.

Ehe operation of the embodiment shown in Figs. 4 to 7 is as follows: An explosive charge is formed in one of the combustion chambers H from fuel injected by the nozzle 52 and air admitted through the inlet valves from the air supply chamber 33. a slug of pressure fluid to travel through the duct l1 tending to create a suction area in its wake. The reduced pressure following the path of the The charge is ignited causing slug causes the relief check valves 42 to open to admit an additional volume of air into the duct to prevent or reduce retardation of the slug of pressure fluid by reduced pressure and also cooling the check valve 3i. The slug and the additional air admitted through the relief check valves 42 pass through the check valve 3| into the common chamber 38 where a reduction of the speed of the slugs and an increase of pressure takes place as mentioned in connection with the previously described embodiments. In the meantime an explosive charge is formed and exploded in the second unit which likewise discharges fluid into the common chamber 38, the two duct-engine units operating alternately. A continuous jet of fluid of predetermined pressure is discharged from the common chamber 38 through the discharge port 39 and propels the air foil by reactive force.

The invention thus provides an effective means for increasing the efliciency of duct-engines by appropriate reduction of the rate of discharge of pressure fluid from the engine resulting in corresponding reduction of losses due to slip. In addition it provides equalized continuous propulsion thrust and reduction of noise due to elimination of individual discharges or bursts of pressure fluid from the engine nozzle. The invention also provides a multiple duct-engine supplying jointly one or several discharge ports with pressure fluid.

Obviously the invention is not restricted to the particular specific embodiment herein shown and described. It is susceptible of various modiflcations and adaptations. The invention is of course applicable to duct-engines in which the succession of explosions is timed by periodic controlled admission of fuel or controlled formation of combustible charges, in distinction from the illustrated forms of engines in which the combustions are controlled by the ignition system. More than two engine duct units may of course be combined to cooperate with one joint chamber or the chambers of several individual units be intercon nected to produce the same result as accomplished by the invention. Various additions and modifications may be made according to specific requirements, for example, check valves may be omitted from the ducts or other forms of relief valves or relief means used than the ones shown.

All such and other modifications, changes, additions, omissions and substitutions may be made by persons skilled in the art without departure from the essence of this invention.

What is claimed is:

1. An intermittent duct engine for aircraft comprising, in combination, a plurality of combustion chambers; a common air supply chamber in heat exchanging relationship with said combustion chambers, surrounding said combustion chambers, and forming the leading portion of an airfoil, said air suppl chamber communicating with the atmospheric air through an intake port in the leading edge of said airfoil portion; admission valves in the head of said combustion chamber for controlling the admission of combustion air under dynamic pressure from said supply chamber into said combustion chambers; means for introducing and igniting in said combustion chamber fuel charges in timed relationship; a duct associated with and rearwardly extending from, the head of each of said combustion chambers through which duct slugs of pressure fluid are moved by the explosion of said charges; a

common storage chamber into which said ducts 6 open, and walls of said storage chamber adjoining the ends of said ducts being divergent with respect to said ducts to provide a path of gradually increasing cross section to slugs of fluid entering from said ducts; and a discharge port directed towards the trailing portion of said airfoil through which fluid is discharged from said common storage chamber.

2. An intermittent duct engine for aircraft comprising, in combination, a plurality of combustion chambers; a common air supply chamber in heat exchanging relationship with said combustion chambers, surrounding said combustion chambers and forming the leading portion of an airfoil, said air supply chamber communicating with the atmospheric air through an intake port in the leading edge of said airfoil portion; admission valves in the head of said combustion chamber for controlling the admission of combustion air under dynamic pressure from said suppl chamber into said combustion chambers; means for introducing and igniting in said combustion chambers fuel charges in timed relationship; a duct associated with each and rearwardly extending from, the head of each of said combustion chambers through which slugs of pressure fluid are moved by the explosion of said charges; relief check valves in said ducts rearwardly with respect to said admission valves, said relief check valves being responsive to the diirerence in pressure between said supply chamber and said ducts for automatically admitting airv into said ducts if the pressure in the supply chamber exceeds the pressure in the respective duct; a common storage chamber into which said ducts open, said storage chamber being in the trailing portion of said airfoil, the walls of said storage chamber adjoining said ducts being divergent with respect to said ducts to provide a path of gradually increasing cross section to slugs of fluid entering from said ducts; and a discharge port directed towards the trailing portion of said airfoil through which fluid is discharged from said common storage chamber. 7

3. An intermittent duct engine as set forth in claim 2 in which a further check valve is provided in each of said ducts, said further check valve being responsive to the difference in pres- 1 sure between the respective duct and said common storage chamber for preventing back flow of fluid from the storage chamber into the duct if the pressure in the duct drops below the pressure of the storage chamber.

PAUL KOLLSMAN.

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

UNITED STATES PATENTS Number Name Date 1,163,333 Galbraith et a1. Dec. 7, 1915 1,983,405 Schmidt Dec. 4, 1934 2,420,323 Meyer et a1 May 13, 1947 FOREIGN PATENTS Number Country Date 424,955 Great Britain Dec. 1, 1933 471,177 Great Britain Aug. 30, 1937 484,405 Great Britain May 2, 1938 517,894 France Dec. 23, 1920 545,444 France July 20, 1922 653,534 France Nov. 9, 1928 233,162 Germany Apr. 1, 1911

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