US3076309A

US3076309A - Aircraft jet propulsion apparatus with thrust reversing means

Info

Publication number: US3076309A
Application number: US799763A
Authority: US
Inventors: Brown David Morris; Colley Rowan Herbert
Original assignee: Rolls Royce PLC
Current assignee: Rolls Royce PLC
Priority date: 1958-04-03
Filing date: 1959-03-16
Publication date: 1963-02-05
Anticipated expiration: 1980-02-05
Also published as: FR1219639A; DE1087908B; GB882424A

Description

Feb. 5, 1963 D. M. BROWN ETAL 3,076,309

AIRCRAFT JET PROPULSION APPARATUS WITH THRUST REVERSING MEANS Filed Mafch 16. 1959 3 Sheets-Sheet 1 Feb. 5; 1963 o. M. BROWN EI'AL 3,07 ,30

AIRCRAFT JET PROPULSION APPARATUS WITH THRUST REVERSING MEANS Filed March 16, 1959 3 Sheets-Sheet 2 Feb. 5, 1963 n. M. BROWN ETAL :AIRCRAFT JET PROPULSION APPARATUS WITH THRUST REVERSING MEANS s Sheets-Sheet 3 Filed March 16. 1959 I ll United States Patent 3,076,309 AIRCRAFT JET PROPULSION APPARATUS WITH THRUST REVERSING MEANS David Morris Brown, Alvaston, and Rowan Herbert Colley, Sunny Hill, Derby, England, assignors to Rolls- Royce Limited, Derby, England, a British company Filed Mar. 16, 1959, Ser. No. 799,763 Claims priority, application Great Britain Apr. 3, 1958 1 Claim. (Cl. 60--35.54)

This invention comprises improvements in or relating to aircraft jet propulsion apparatus and is concerned more particularly with such apparatus comprising a jet pipe with a propulsion nozzle at its outlet end and means for obtaining reverse thrust, for instance for aircraft braking purposes, which means includes a duct receiving gas from the rearwardly-extending exhaust gas path and housing a vaned structure for assisting to impart to gas flowing in the duct a component of velocity in a direction reverse to the direction of flow in the jet pipe. Such apparatus will be referred to as being of the class speci- According to the present invention, the vaned structure of jet propulsion apparatus of the class specified comprises first vane means to assist to impart to the gas a component of velocity in a first direction and second vane means extending transversely to the first vane means to assist to impart to the gas a component of velocity in a direction inclined to the first direction so that the reverse thrust jet issuing from the vaned structure has components of velocity in two directions mutually at right angles to one another and to the direction of gas flow at the entry side of the vaned structure. For instance, where the vaned structure is in a lateral duct extending from a jet pipe the first vane means may impart a forward component of velocity and the second vane means may impart a vertical component of velocity, the direction of gas flow at the entry of the vaned structure beingsubstantially horizontal and laterallyof the jet propulsion apparatus.

Preferably, the first and second vane means are arranged so that the gas is acted upon simultaneously by both vane means, and in one such an arrangement the first vane means is in the form of cascades of vanes arranged side by side and separated by strip-like support members for the vanes, and the support members are so inclined to the direction of gas flow at the entry to the grid structure as themselves to form the second vane means.

Preferably, the vaned structure is so constructed and so supported in the jet propulsion apparatus as to avoid overstressing due to thermal expansion, and in one construction in which cascades of vanes are separated by support members as jet set forth, some of the support members are made relatively flexible as compared with other (and relatively rigid) support members, there being a relatively flexible support member next adjacent each of the relatively rigid support members on each side of it, the vanes of the cascade on one side of each rela tively rigid support member being attached to it at positions level with the vanes of the cascade on the other side of the support member, and the vanes of the eascade on one side of a relatively flexible member being staggered lengthwise of the member relative to the vanes of the cascade on the other side of the member. Such a vaned structure may be supported in the jet propulsion apparatus along one side of the vaned structure by rigidly securing the adjacent ends of the rigid support members to a wall of the duct and along the opposite side of the vaned structure by providing sliding connections between the rigid support members and another wall of the duct.

One embodiment of this invention will now be described with reference to the accompanying drawings in which:

FIGURE 1 is a view, with parts broken away, of an engine of an aircraft,

FIGURE 2 is a view to a larger scale in the direction of arrow 2 on FIGURE 1,

FIGURE 3 is a view in the direction of arrow 3 on FIGURE 2,

FIGURE 4 is a section on the line 4-4 of FIGURE 3, and

FIGURE 5 is a section to a larger scale on the line 5-5 of FIGURE 2.

Referring to FIGURE 1, one of the engines 12 of a multi-engined aircraft is shown diagrammatically and it comprises a compressor 14, combustion equipment 15, a turbine 16 and an exhaust assembly 17 connected in flow series between an air intake 18 formed by the leading part of a nacelle 19 housing the engine and a propulsion nozzle 20 through which exhaust gases pass to atmosphere.

The exhaust assembly 17 is arranged so that, when necessary, a reverse thrust can be obtained for braking the aircraft and the means for reversing the thrust is shown as comprising a pair of jet pipe doors 21, 22 pivoted about a diameter of a jet pipe 17a which connects the turbine 16 with nozzle 20, to swing between a normal thrust position in which the doors 21, 22 blank off apertures of a vaned structure 23 in the jet pipe and permit the exhaust gases to flow to the nozzle 20, and a reverse thrust position as shown in which the gases are constrained to flow through the apertures of the vaned structure 23 which assist to impart a forward velocity component to the gases before they flow to atmosphere through apertures in the nacelle 19 as forwardly directed jets.

In order to prevent a forwardlydirected jet from the engine from interfering with the operation of an adjacent engine, it is arranged that the vaned structure 23 on the side of the engine 12 adjacent another engine causes the forwardly-directed jet issuing therefrom also to be deflected downwards. In some aircraft arrangements a similar deflection of all the forwardly-directed jets from an engine may be necessary for instance to avoid damage or b'ufieting of adjacent aircraft parts.

In order to obtain such' additional deflection of the jets, and also to accommodate' relative thermal expansion without overstress'ing, atconstruction-of vaned structure as shown in FIGURES 2 to 5 may be employed.

The vaned structure is curved (FIGURE 3) to follow the contour of the jet pipe and is shaped in the fore and aft direction (see FIGURE 3) according to the axial contours of the jet pipe 17 and nacelle 19.

The vaned structure comprises a series of cascades of guide vanes 25, each cascade comprising a row of circumferentially-short, radially-curved vanes arranged one behind the other in the fore and aft direction as will be seen in FIGURE 4, the vanes 25 being arranged with their concave faces directed forwardly so that gas passing between the vanes which at the entry to the vaned structure is flowing in a substantially horizontal direction at right angles to the fore and aft direction, is given a component of velocity in the forward direction. The vanes are supported by fore and aft extending

striplike support members

26, 27, there being at least one support member 26 on each side of a support member 27, the vanes extending circumferentially between the

members

26, 27.

As will be seen from FIGURES 2 and 3, the members 26- and 27 are substantially parallel to one another and are inclined to the radial direction from the axis of the 3 engine so that thesemembers also act as second vane means to deflect the gas flowing through the structure. The inclination is selected so as to impart the desired additional deflection of the gases.

In order to accommodate relative thermal expansion of the parts of the grid structure without overstressing it, the following arrangement may be adapted.

The members 2-6 are made thinner than the members 27 so that the members 26 are more flexible than the members 27. Also, as will best be seen from FIGURES 2 and 4, the vanes 25 of the cascade joined to one side of each thick member 27 are level with the vanes of the cascade joined to the opposite side of the member, whilst .the vanes 25 of the cascade joined to one Side of each thin member 26 are staggered in the fore and aft direction with respect to the vanes of the cascade joined to the opposite side of the thin member 26. Thus, for instance, in-FIGURE 2, the vanes 25a of the righthand cascade are joined to the right-hand thick member 27a at positions level with the vanes 25b of the cascade on ;the opposite side of the member 27a, and the vanes 250 .of the left-hand cascade are joined to the letthand thin .member 26a at positions staggered with respect to the vanes 25d on the opposite side of the thin member 26a. Relative expansion of the vanes can thus be accommodated in part by sinuous bending of the thin support members 26. The outer ends of the vanes 25a and 25c .are joined by thin sheet metal walls 28.

The grid structure is supported in the nacelle in the following way. The thick members 27 are provided at their forward ends with flanges 30 which are bolted to 'facings 31 (FIGURE 2) secured on a wall 32 forming the forward end of a duct between the apertures of the structure 23 in the jet pipe and the apertures in the ,nacelle 19, and are provided at their rearward ends with plug pieces 33 (FIGURE which are slidingly received in sockets 34 secured to a rear wall 35 of the duct. Thus fore and aft expansion of the grid structure is permitted relative to the structure in which it is supported.

The walls 28 are provided near their ends which are adjacent the flanges 30, with bushes 37 which are aligned with sleeves 38 mounted in the walls of the duct, and locating members 38a are provided which are threaded into the sleeves 38 and project from the sleeves 38 to have a pivotal and sliding engagement with the bushes 37.

We claim:

In jet propulsion apparatus comprising a jet pipe through which exhaust gas flows, a propulsion nozzle mounted on the jet pipe at one end and forming a first outlet for the exhaust gas, an aperture in the jet pipe upstream of the nozzle forming a second outlet, de-

flector means within the jet pipe, said deflector means having an operative setting in which exhaust gas is deflected towards the second outlet and an inoperative setting in which exhaust gas flows to the propulsion nozzle, and a vaned structure mounted in the second outlet imparting to gas flowing through the second outlet a component of velocity in a direction opposite to the direction of flow in the jet pipe; said vaned structure comprising a plurality of first vanes spaced apart lengthwise of the jet pipe one behind the other, each first vane extending circumferentially of the j t pipe, and each first vane imparting to the exhaust gas said component of velocityin the direction opposite to,the direction of gas flow in the jet pipe, said first vanes being disposed in a number of cascades disposed side by side, and a plurality of second vanes spaced apart circumferentially of the jet pipe, the second vanes being constituted by strip members extending longitudinally of the jet pipe and separating the said cascades of said first vanes One from the other, the strip members being interconnected by the first vanes, the strip members being in planes inclined at an angle to the radial direction from .the

center line of the jet pipe to the mid point of the vaned structure, said second vanes acting together and deflecting the exhaust gas jet from said vaned structure as a whole to be inclined to a plane containing both the jet pipe axis and said radial direction and to impart to the gas a component of velocity in a direction at right angles to both said radial direction and said oppositedirection, some of the strip members being relatively flexible and other strip members being relatively rigid, there being at least one relatively flexible strip member between each relatively rigid member and the adjacent relatively rigid member, the first vanes forming the cascades attached .to each side of each relatively rigid member being at level positions lengthwise of the rigid member, and the first vanes of the cascade attached to one side of a relatively flexible member being staggered lengthwise of the member relative to the first vanes of the cascade attached to the other side of the member.

References Cited in the file of this patent UNITED STATES PATENTS FOREIGN PATENTS 754,065 Great Britain Aug. 1, 1956