GB2080230A

GB2080230A - Jet nozzle rotary wing aircraft

Info

Publication number: GB2080230A
Application number: GB8121358A
Authority: GB
Original assignee: Individual
Current assignee: Individual
Priority date: 1980-07-14
Filing date: 1981-07-10
Publication date: 1982-02-03
Also published as: DE3127663A1; IT1171385B; JPS5787795A; IT8148893A0; FR2486491B3; FR2486491A1

Abstract

A rotary wing aircraft includes a fuselage, a gas turbine engine operated air compressor within the fuselage, and a jet nozzle driven rotor assembly situated over the fuselage and including a plurality of jet nozzle driven rotor blades 38 having air conduit means 42 extending therethrough. A propulsion nozzle 60 is located at the tip of each rotor blade for exhausting gases to produce rotation of the rotor assembly. A braking nozzle 62 also is located at the tip of each rotor blade for exhausting gases to produce a braking action on the rotor assembly. A diverter valve 64 is operatively associated with the propulsion and braking nozzles for alternately directing the exhausting gases into one of the nozzles. A cover 68 is provided for closing the open end of the braking nozzle to eliminate drag on the rotor assembly when the rotor assembly is being rotated by exhausting gases through the propulsion nozzle 60. <IMAGE>

Description

SPECIFiCATION Jet nozzle rotary wing aircraft This invention relates to rotary wing aircraft, and in particular to a jet nozzle driven rotary wing aircraft in which means is provided for reversing the thrust of the jets to produce a braking action of the rotor assembly.

Ground accidents are a continuing problem with rotary wing aircraft, such as helicopters. It is unfortunate, but true, that a large proportion of ground accidents in helicopter operations is caused by the rotor assembly of the aircraft continuing to turn after the aircraft has landed. This is particularly true for close-in operations, such as shipboard landings, oil rig service, military operations, ambulance functions and the like.

Furthermore, crash-landing accidents in rotary wing aircraft often-times are enhanced in magnitude by the fact that the rotating blades cause significant additional impacting forces when the aircraft hits the ground or standing structures thereon.

The development of high performance lightweight gas turbines has made it increasingly feasible to power the rotor assembly of a helicopter by ducting compressed air and/or the turbine gases directly to jet nozzles located at the rotor blade tips. Such an aircraft offers a simple method for stopping the rotor assembly within a matter of seconds. This has been done by reversing the thrust of the reaction jets to produce a braking action of the rotor assembly. The exhaust gases are diverted through a braking jet in the leading edge of one or more of the rotor blades.

However, many problems are encountered with such a system, one of which isthatthe braking nozzle creates drag on the rotor assembly when the rotor assembly is being rotated in a normal propelling mode.

It would, therefore, be desirable to provide in a rotary wing aircraft, a new and improved means for braking the action of the rotor assembly without creating drag thereon in normal driven operation thereof.

Thus, the present invention provides a rotary wing aircraft which includes a fuselage, air compressor means on said fuselage, a jet nozzle driven rotor assembly situated over said fuselage and having a rotor axis about which said assembly rotates, said rotor assembly including a plurality of jet nozzle driven rotor blades extending radially outwardly of said axis and having air conduit means extending radially therewithin, propulsion nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce rotation of said rotor assembly, braking nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce a braking action on said rotor assembly, diverter valve means operatively associated with said propulsion nozzle means and said braking nozzle means for alternately directing said gases into one of said nozzle means, and cover means for closing the open end of said braking nozzle means to eliminate drag on said rotor assembly when the rotor assembly is being rotated by exhausting gases through said propulsion nozzle means.

The cover means includes a pair of pivotally mounted cover plates which are movable toward and away from each other between closed and open positions, respectively. The cover plates are spring loaded so as to be biased toward their closed positions, and the cover plates are opened against the spring load thereof automatically in response to gases being directed through the braking nozzle means. The cover plates are complementarily shaped so as to combine to conform to the adjacent aerodynamic contour of the respective rotor blade when the plates are in their closed positions.

Motor means is provided for selectively moving the diverter valve means between alternate positins to effect the alternate directing of gases into one of the propulsion or braking nozzle means. In one form of the invention, drive means is operatively associated between the motor means and the cover means for positively effecting opening and closing of the cover means in unison with movement of the divertervalve means.

Other advantages and features of the invention will be apparent from the following detailed description taken in connection with the accompanying drawings, in which: FIGURE 1 is a side elevational view of a jet nozzle driven rotary wing aircraft embodying the concepts of the present invention, partially broken away and in section to better illustrate various operative components of the invention; FIGURE 2 is a fragmented perspective view, on an enlarged scale, of the tip of one rotor blade partially broken away to facilitate the illustration of the diverter valve means and cover means in propulsion condition; FIGURE 3 is a view similar to that of Figure 2, with the diverter valve means and cover means in braking condition; and FIGURE 4 is an end elevational view of one rotor blade, partially broken away and illustrating the cover means in closed condition.

Referring to the drawings in greater detail, and first to Figure 1, a rotary wing aircraft in the form of a helicopter is shown and includes a fuselage, generally designated 10, and a jet nozzle driven rotor assembly, generally designated 12. A lightweight gas turbine engine 14 is appropriately mounted within the fuselage 10 and is effective to operate an air compressor 16. An exhaust tunnel 18 extends rearwardly of engine 14 to direct exhaust gases rearwardly toward a vertical rear fin 20 which is provided for yaw control.

The aircraft also includes a plexiglass cockpit area, generally designated 22, within which is disposed conventional equipment such as an operator's seat 24, a control panel 26, a collective pitch stick 28, and a conventional cyclic pitch stick 30 which has a thumb switch 32 on the top thereof. Landing skids 34 are mounted on the underside of fuselage 10 by appropriate brackets 36, or the iike, with shock absorbers 37 extending rearwardly and connected to the skids 34.

The rotor assembly 12 is of the jet nozzle driven type and includes a plurality of generally hollow rotor blades 38 with jet nozzle means, generally designated 40 in Figure 1, at the distal ends thereof.

The jet nozzle means extend generally tangentially of the rotor blades at the blade tips and are effective to discharge the compressed air, resulting in rotor rotation. Air conduit means 42 extends radiallyout- wardly through the rotor blades.

Rotor support means is provided for supporting the rotor assembly 12 for rotation about a central vertical axis defined by a rigid air duct 44 which is mounted within an opening atthe top offuselage 10.

Rigid air duct 44 extends into the fuselage and is in communication with the air compressor 16 by an air conduit portion 46. The compressed air is directed upwardly from the air compressor through conduit portion 46, in the direction of arrow A, and upwardly and outwardly through the rigid airduct 44, as indicated by the double headed arrow B, into the air conduit means 42 of the rotor blades 38. A rotor hub 48 is mounted for rotation about a collar 50 secured to the rigid air duct 44, with a dust skirt 52 extending downwardly therefrom.

It should be noted atthistime that appropriate means, not shown in the drawings in orderto avoid cluttering the illustration, is provided between the rotor assembly, collar and fuselage to hold the rotor assembly and rotor hub and yet provide for rotation thereof. Of course, various such conventional means which does notform a part of the present invention are known and are contemplated.

Referring to Figures 2 and 3, the tip of one rotor blade 38 is shown with air conduit means 42 extending outwardlytherewithin to the tangentially disposed jet nozzle means 40. A propulsion nozzle 60 is located in the trailing edge of the blade tip for exhausting gases from air conduit means 42 out- wardly in the direction of arrow C to produce rotation of the rotor blade and rotor assembly 12 in a driving or normal lifting operative mode. A braking nozzle 62 is disposed in the tip of blade 38 for communication with air conduit means 42 for exhausting gases outwardly through the leading edge of the rotor blade in the direction of arrow D (Figure 3), to produce a braking action on the rotor blade and rotor assembly 12.

Divertervalve means in the form of a concave valve plate 64 is pivotally mounted for movement about a generally vertical pivot axis 66 for alternately directing gases from airconduit42 into one of lye propulsion or braking nozzles 60 or 62, respectively.

Figure 2 shows the diverter valve plate 64 in position whereby exhausting gases from airconduit42 are diverted in the direction of arrow E so as to be exhausted outwardly through propulsion nozzle 60 in the direction of arrow C.

Figure 3 shows diverter valve plates 64 pivoted from the position shown in Figure 2 to a position whereby gases are diverted from air conduit 42 in the direction of arrow F into braking nozzle 62 and outwardly in the direction of arrow D, through the leading edge of the rotor blade 38.

In order to eliminate drag on the rotor assembly when the rotor assembly is being rotated by exhausting gases through propulsion nozzle 60, cover means, generally designated 68, is provided for closing the open end of braking nozzle 62. More particularly, cover means 68 comprises a pair of pivotally mounted cover plates 70 which are movable toward and away from each other between closed and open positions, respectively. The closed positions of the cover plates are shown in Figures 2 and 4, and the open positions thereof are shown in Figure 3. The cover plates are spring loaded by appropriate coil springs wrapped about pivot shafts 72 (Figure 4) or other appropriate means, so as to be biased toward their closed positions.Thus, the cover plates can be opened against the spring load thereof automatically in response to the exhaust gases being diverted by valve plate 64 into and through braking nozzle 62 against the inside surfaces of the spring loaded cover plates.

Figure 4 shows an important feature of the invention wherein it can be seen that the cover plates 70 are complementarily shaped so as to combine to conform to the adjacent aerodynamic contour of the leading edge of rotor blade 38 when the plates are in their closed positions. Thus, not only does cover means 68 eliminate drag on the rotor assembly when the rotor assembly is being rotated by exhausting gases through propulsion nozzle 60, but the outer contour of cover plates 70, conforming to the aerodynamic contour of the leading edge of the rotor blade, actually fulfills this aerodynamic function of the aircraft.

Figure 4 also shows motor means 74 within blade 38 for selectively moving diverter valve 64 about its vertical axis of rotation 66. The motor is operatively associated with the divertervalve 64 by appropriate means, and can be appropriately operated by controls within the cockpit area 22 through control lines leading to the motor through the rotor assembly.

Figure 4 also shows a drive means between motor 74 and cover plates 70 for positively effecting opening and closing of the cover plates in unison with movementofthe divertervalve plate 64. More particularly, various appropriate connecting means, such as drive chains, pulleys and belts, or other driving mechanisms may be operatively connected between motor74 and the upper cover plate 70, as indicated at 76. Furthermore, a pulley, gearorother drive member 78 can be mounted on the underside of valve plate 64 beneath pivot axis 66 to drive the lower cover plate 70, through driving means as at 80.

It will be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not to be limited to the details given herein.

Claims

1. Arotarywing aircraft which includes afusel age, air compressor means on said fuselage, a jet nozzle driven rotor assembly situated over said fuselage and having a rotor axis about which said assembly rotates, said rotor assembly including a plurality of jet nozzle driven rotor blades extending radially outwardly of said axis and having air conduit means extending radiallytherewithin, propulsion nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce rotation of said rotor assembly, braking nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce a braking action on said rotor assembly, diverter valve means operatively associated with said propulsion nozzle means and said braking nozzle means for alternately directing said gases into one of said nozzle means, and cover means for closing the open end of said braking nozzle means to eliminate drag on said rotor assembly when the rotor assembly is being rotated by exhausting gases through said propulsion nozzle means.

2. An aircraft according to claim 1 wherein said cover means is spring loaded so as to be biased toward a closed condition, said cover means being opened against the spring load thereof automatically in response to said gases being directed through said braking nozzle means.

3. An aircraft according to claim 2 wherein said cover means is shaped so as to conform to the adjacent aerodynamic contour of said rotor blade when said cover means is in closed condition.

4. An aircraft according to claim 1 wherein said cover means comprises a pair of pivotally mounted cover plates which are movable toward and away from each other between closed and open positions, respectively.

5. An aircraft according to claim 4wherein said cover plates are spring loaded so as to be biased toward their closed positions, said coverplates being opened againstthe spring load thereof automatically in response to said gases being directed through said braking nozzle means.

6. An aircraft according to claim 5 wherein said cover plates are complementarily shaped so as to combine to conform to the adjacent aerodynamic contour of said rotor blade when said plates are in their closed positions.

7. An aircraft according to claim 1 wherein motor means are included for selectively moving said diverter valve means between alternate positions to effect said alternate directing of gases into one of said nozzle means.

8. An aircraft according to claim 7 wherein drive means are included between said motor means and said cover means for positively effecting opening and closing of said cover means in unison with said movement of said diverter valve means.

9. An aircraft according to claim 1 wherein motor means operatively associated with said cover means are included for positively opening and closing said cover means.

10. An aircraft according to claim 1 wherein said cover means is shaped so as to conform to the adjacent aerodynamic contour of said rotor blade when said cover means is in closed condition.

11. A rotary wing aircraft which includes a fuselage, air compressor means on said fuselage, a jet nozzle driven rotor assembly situated over said fuselage and having a rotor axis about which said assembly rotates, said rotor assembly including a plurality ofjet nozzle driven rotor blades extending radially outwardly of said axis and having air conduit means extending radially therewithin, propulsion nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce rotation of said rotor assembly, braking nozzle means in at least one of said rotor blades generally at the tip thereof for exhausting gases from said air conduit means to produce a braking action on said rotor assembly, diverter valve means operatively associated with said propulsion nozzle means and said braking nozzle means for alternately directing said gases into one of said nozzle means, and cover means in the form of a pair of cover plates for closing the open end of said braking nozzle means to eliminate drag on said rotor assembly when the rotor assembly is being rotated by exhausting gases through said propulsion nozzle means, said cover plates being movable toward and away from each other between closed and opened positions, respectively, and said cover plates being complementarily shaped so as to combine to conform to the adjacent aerodynamic contour of said rotor blade when said plates are in said closed positions.

12. An aircraft according to claim 11 wherein said cover plates are spring loaded so as to be biased toward said closed positions, said cover plates being opened against the spring load thereof automatically in response to said gases being directed through said braking nozzle means.

13. An aircraft according to claim 11 wherein motor means are included for selectively moving said divertervalve means between alternate positins to effect said alternate directing of gases into one of said nozzle means.

14. An aircraft according to claim 13 wherein drive means are included between said motor means and said cover means for positively effecting opening and closing of said cover means in unison with said movement of said diverter valve means.

15. An aircraft according to claim 11 wherein motor means operatively associated with said cover means are included for positively opening and closing said cover means.

16. An aircraft according to claim 11 wherein said cover plates are pivotally mounted to said rotor blade for movement between said positions about generally parallel pivot axes generally parallel to the radially extending direction of said rotor blade.

17. A rotary wing aircraft which includes a jet nozzle driven rotor assembly, the improvement comprising means for reversing the thrust of the jets of said rotor assembly for exhausting gases through braking nozzle means to produce a braking action on said rotor assembly, and cover means for closing the open end of said braking nozzle means to eliminate drag on said rotor assembly when the rotor assembly is being rotated in normal driving mode.

18. An aircraft according to claim 17 wherein said cover means is shaped so as to conform to the adjacent aerodynamic contour of the rotor blade when said cover means is in closed condition.

19. A rotary wing aircraft substantially as hereinbefore described with reference to the accompanying Figures 14.