US3394907A - Lift jet engine - Google Patents

Description

July 3%, 1968 w s. CASTLE ET AL 3,394,907

LIFT JET ENGINE Filed Sept. 15, 1966 2 Sheets-Sheet l INVENTORS N 5527/1222??? faz/eg an: m 41 j Z BY floz 'as/fifian uaxz A 7' TOR-NE y July 30, 1968 w. s. CASTLE ET AL 3,394,907

LIFT JET ENGINE Filed Sept. 15, 1966 2 Sheets-Sheet 2 R n m s r A 7 w 4 (1* '"Tlt' A 5 N v i Q Q 5 Q Q I INVENTORS g (Z/z/lzazzz Casi/e By k'emg/ 77. 27.476; flOZiQ/Qi/f kam wa/z m M ATTORNEY United States Patent 3,394,907 LIFT JET ENGINE William S. Castle, Speedway, and Henry Ming Mar, In-

dianapolis, Ind., and Douglas K. Thompson, Derby, England, assignors to General Motors Corporation, Detroit, lVIich., a corporation of Delaware Filed Sept. 15, 1966, Ser. No. 579,689 11 Claims. (Cl. 244-52) ABSTRACT OF THE DISCLOSURE A variable jet installation for a lift engine. The engine has a jet nozzle of rectangular outline with flow deflecting vanes at the sides of the nozzle and doors which close the outlet to the deflecting vanes but which can be rotated about axes at the nozzle outlet to obstruct the normal outlet and deflect flow through the deflecting vanes towards both sides of the aircraft. Additional vanes pivoted at the nozzle outlet and extending downward from it may be moved to provide a sidewise component of thrust from the lift jet. A door pivoted about an axis transverse to the aircraft can close the bottom of the nacelle but may be opened fully to clear the jet or opened partially to deflect the jet rearwardly to provide some forward thrust.

Our invention relates to jet propulsion or jet thrust engines and primarily to the control of the jet discharged from such engines. While features of our engine may be usable in various environments, the preferred embodiment of the invention is in a vertical lift jet installation. In such installations a jet engine, such as a turbojet or turbofan engine, is mounted so that its axis remains substantially vertical when the aircraft is in normal attitude. Such engines are used only for lifting the aircraft from and lowering it to a landing place. Normal propulsion of the vehicle is accomplished by other engines.

' Our invention in its preferred form is adapted to minirnize some of the disadvantages of direct lift jets and improve the desirability of such installations. It includes an arrangement whereby the engine can be brought up to speed while the jet is deflected so as to substantially destroy: lift and also substantially eliminate ground erosion. It embodies a jet nozzle of approximately rectangular form which also reduces ground erosion during the period of maximum impact of the jeton the surface. It includes vanes adapted to deflect the jet from the nozzle sideward so as to provide a lateral thrust component usable or yaw control of the aircraft. It further includes a nacelle door closing the lower end of the nacelle or chamber within which the engine is mounted, which door may be moved to deflect the jet rearward to provide a measure of forward thrust during conversion from direct lift to forward flight.

These features and advantages are accomplished with a simple and particularly practical structure as will be seen from the succeeding description. It will be understood, of course, that some of the features of our invention may be omitted in certain installations; however, for the direct lift installation described herein we believe that the entire engine described would ordinarily be most neuvering of the aircraft when the lift engines are inoperation. A further object is to provide an improved combination of thrust spoiling means and thrust vectoring means in a jet lift or propulsion engine.

The nature of our invention and the advantages thereof will be apparent to those skilled in the art from the succeeding detailed description of the preferred embodiment thereof and the accompanying drawings.

FIGURE 1 is an elevation view of the exhaust end of an engine mounted in a nacelle, with parts cut away and in section.

FIGURE 2 is a bottom view of the jet engine taken on the plane indicated by the line 2-2 in FIGURE 1.

FIGURE 3 is a transverse sectional view of the installation with parts cut away along the plane indicated by the line 33 in FIGURE 1, and

FIGURE 4 is an axonometric view of the jet nozzle and associated structure.

The accompanying drawings show only the exhaust end of the jet engine and the lower end of the nacelle, since the details of the gas generator portion of the engine and of the part of the nacelle remote from the lower end thereof are immaterial to our invention and may embody any suitable structure.

The jet engine 5 includes an exhaust duct 6 within which there may be the usual inner cone 7. The exhaust duct, which is of circular or annular cross section, is connected to a substantially rectangular jet nozzle 8. In its preferred form the nozzle has arcuate front and rear edges 9 and parallel straight side edges 10 (see FIGURE 2) which extend in a fore and aft direction in the aircraft. The exhaust duct is connected to the jet nozzle by a transition section 13 having flat converging sides normally defined by diverter means or diverter doors 14 which are mounted to swing about the hinge axis 11 as indicated by the broken lines in FIGURE 3.

A fixed turning vane assembly 15 including a cascade of vanes 17 is fixed over the opening controlled by each of the diverter doors 14, one such cascade at each side of the engine, terminating at the line of the hinges 11. A deflectable vane 18 is also mounted on hinge axis 11 at each side of the nozzle. The vanes 18 are essentially flat plates having end portions 19 folded up to form actuating arms connected to the rods 21 of power cylinders or jacks 22 which are operable to swing the vanes 18 as indicated by the broken outlines in FIGURE 3. Preferably, there are four cylinders 22 mounted both at the forward and rear sides of the engine. These cylinders may react against a flange 23 on the engine 5.

The doors 14 and vanes 18 are provided with ears which are alternated with ears extending from the side of the jet nozzle to provide the plural hinge structure indicated at 11 for the doors and vanes. The deflector doors are each integral with two laterally extending arms 25 which are coupled to the rods 26 of actuating cylinders 27 which provide for moving the door between the normal closed position indicated in solid lines in FIGURE 3 and the open position indicated by the broken lines in FIG- URE 3. Cylinders 27 are also connected to the flange 23.

The engine is mounted in a nacelle 30 having an air inlet (not shown) at the upper end and defining a chamber having a front wall 31, a rear wall 33, and side walls 34. The engine may be fixed in the nacelle in any suitable manner. The lower end of the nacelle below the jet nozzle and yaw vanes may be closed by a bottom door 37 (FIGURES 1 and 3) which also may serve as a deflector plate for the jet. The plate or door 37 is integral with hinge knuckles 38 which alternate with knuckles 39 extending from the forward wall of the nacelle so that the door may be moved from its closed position shown in FIGURE 1 to a wide open position in which it extends more or less vertically downward. In some cases deflector 37 may be supported directly from the engine. As illustrated in FIGURE 3, the door 37 has side flanges 41 so that it has a slight trough shape. The door 37 is fixed to a shaft 43 which in turn is fixed to actuating arms 45 by which the position of the door is controlled. These arms may be operated by power cylinders of which only the piston rods 46 are illustrated, or by any other suitable means. It will be noted that the vanes 18 can be retracted to a nearly closed position as illustrated in FIGURE 3 to clear the door 37 when the lift engine is not in operation. Normally, however, they depend from the nozzle generally as indicated in FIGURE 4 and by the broken lines in FIGURE 3.

Since the lower part of the engine including the gas turning cascades is mounted within the nacelle, movable side doors 49 are provided on the nacelle which open to permit the direct discharge of the horizontal jet from the turning vanes. The doors 49 are hinged along forward and aft line hinge lines at 50. While they may be power actuated, it is suflicient to provide means to bias them closed such as a spring 51 connected between an arm 53 rigid with the door and an anchor-age 54 on the forward wall of the nacelle. When the lift engine is in normal operation, the jet from the engine tends to create a vacuum within the nacelle which tends to pull the side doors closed.

Considering now the operation of the engine, it is contemplated that the engine will be started and run up with the deflector door 37 open and the diverter doors 14 moved to the broken line position of FIGURE 3, the vanes 18 being opened to minimize back pressure. The exhaust from the engine is thus mainly deflected through the side doors 49 which are opened by the jet blast or by any other means. The horizontal deflection of most of the jet minimizes direct impingement of the jet on the landing strip which in some cases may be extremely undesirable. When the engine is run up and the aircraft is in readiness for take-off, diverter doors 14 are moved into engagement with the turning vane assembly. The lifting jet is thus all directed straight down to provide maximum lift. If a side force is needed to yaw the airplane, both of vanes 18 may be swung slightly to the right or to the left to create a yaw component of thrust as desired. In this connection, the provision of these vanes on the long flat side of the jet nozzle provides for better turning effect, partly because the flow tends to follow the outwardly inclined straight vane due to the Coanda effect. The oblong shape of the nozzle reduces ground erosion effects during ground take-off in comparison to a circular nozzle. In this connection, while the proportions of the nozzle may vary, it is preferred that the major dimension of the nozzle outlet be approximately twice its width. The disposition of the engine in the open nacelle which provides a flow path around the engine minimizes suck-down effects on the aircraft which might otherwise be generated by flow over the underside of the fuselage or nacelle induced by the jet from the engine.

When the aircraft is airborne, a certain amount of forward thrust may be provided by swinging the nacelle door rearwardly so that it is impinged by the lift jet, thereby deflecting the jet rearwardly of the aircraft. It is contemplated that the jet from the engine may be deflected something of the order of 30 rearwardly, and also something like to either side for yaw control by the vanes 18. When the lift engines are no longer needed, they are shut down and the door 37 is closed. Also, doors in the upper end of the nacelle (not illustrated) are ordinarily closed under normal flight conditions. The operation of the engine for landing the aircraft is essentially the same as that for take-off.

It should be apparent from the foregoing to those skilled in the art that our invention provides a highly advantageous jet engine of simple structure and considerable flexibility f operation and provides a superior lift engine installation.

It should be understood that the detailed description of the invention for the purpose of explaining the principles thereof is not to be construed as limiting, since many modifications may be made by the exercise of skill in the art within the scope of the invention.

We claim:

1. A jet engine comprising, in combination,

an annular exhaust duct 2. generally rectangular jet nozzle having substantially parallel sides a transition section from the exhaust duct to the nozzle turning means in the transition section adapted to direct engine exhaust laterally outward from the said sides diverter means at the said sides of the nozzle each movable between a position closing a turning means and a position opening the turning means and diverting exhaust gas to the turning means and vanes pivotally mounted, independent of said diverter means at the said sides of the nozzle extending downstream from the nozzle movable concurrently in the same direction about axes at the said sides so as to deflect the engine exhaust variably to one or the other side to provide a variable lateral thrust component.

2. A jet engine as recited in claim 1 in which the transition section is bounded in part by substantially plane surfaces converging toward the said sides of the nozzle the turning means is a cascade of vanes mounted in the said surfaces and the diverter means is a door rotatable to and away from the vane cascade.

3. A jet engine as recited in claim 1 in which the diverter means is a pivoted door and the diverter means and vanes are hinged on a common axis at each side of the nozzle.

4. A jet engine as recited in claim 1 including also a deflector plate downstream of the vanes mounted for rotation about an axis offset from the jet nozzle and transverse to the vane axes, the deflector plate being movable from an open position clear of the jet from the said nozzle to a position wherein it is impinged by the jet and is operable to deflect the jet to provide a thrust component transverse to the said lateral component.

5. A jet engine as recited in claim 4 in which the transition section is bounded in part by substantially plane surfaces converging toward the said sides of the nozzle the turning means is a cascade of vanes mounted in the said surfaces and the diverter means is a door rotatable to and away from the vane cascade.

6. A jet engine as recited in claim 4 in which the diverter means is a pivoted door and the diverter means and vanes are hinged on a common axis at each side of the nozzle.

7. An aircraft having a vertical lift jet engine installation comprising, in combination,

a nacelle having a bottom opening a jet engine mounted in the nacelle with the engine axis upright the engine having an annular exhaust duct, a substantially rectangular jet nozzle having sides substantially parallel to the longitudinal axis of said aircraft, and a transition section from the exhaust duct to the nozzle yaw vanes pivotally mounted on the said sides of the nozzle extending downwardly from the nozzle movable to deflect the engine exhaust to provide a lateral thrust component for yaw control and a bottom door on the nacelle hinged about an axis forward of the jet nozzle and transverse to said longitudinal axes of said aircraft, the bottom door being movable from a position closing the nacelle opening to a position clear of the jet exhaust from the said nozzle.

8. An installation as recited in claim 7, the bottom door being operable to an intermediate position between the aforementioned positions wherein it is impinged by the jet exhaust and is effective to deflect the jet exhaust rearwardly to provide a forward thrust component.

9. An aircraft having a vertical lift jet engine installation comprising, in combination,

a nacelle having a bottom opening a jet engine mounted in the nacelle with the engine axis upright the engine having an annular exhaust duct, a substantially rectangular jet nozzle having sides substantially parallel to the longitudinal axes of the aircraft, and a transition section from the exhaust duct to the nozzle turning means in the transition section adapted to direct the engine exhaust substantially horizontally diverter means at the said sides of the nozzle each movable between a position closing said turning means and a position opening said turning means and diverting exhaust gas to said turning means and nacelle side doors in the Way of the exhaust when diverted by the turning means, the side doors being operable to clear the said diverted exhaust.

10. An installation as recited in claim 9 including also a bottom door on the nacelle hinged about an axis transverse to the longitudinal axis of said aircraft and forward of the jet nozzle and transverse to the aforementioned hinge axes, the bottom door being movable from a position closing the nacelle opening to a position clear of the jet exhaust from the said nozzle.

11. An installation as recited in claim 10, the bottom door being operable to an intermediate position between the aforementioned positions wherein it is impinged by the jet exhaust and is effective to deflect the jet exhaust rearwardly to provide a forward thrust component,

References Cited UNITED STATES PATENTS 8/1967 Opfer et al. 244--52 5/1964 Gardiner et a1. 239-26529 X

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