Rotary jet engine

A rotary jet engine including a housing having intake and exhaust zones separated from each other. At least one combustion jet is mounted on a rotor having an intake spaced from the axis of rotation for effecting ram air delivery of air from the intake zone. Exhaust from the combustion jet causes rotation of the rotor while the intake and exhaust separator inhibits flow from said exhaust zone to said intake zone.

This application is a 371 continuation of PCT/AU93/00029, filed Jan. 21, 
1993. 
TECHNICAL FIELD 
THIS INVENTION relates to a rotary engine which uses a fluid jet for power 
generation (hereinafter be referred to as a "rotary jet engine"). 
BACKGROUND OF THE INVENTION 
With engines which utilise an expanding fluid to drive an output shaft, it 
is common to have a working chamber which varies in volume upon expansion 
of the fluid. The working chamber is usually defined between wall 
surfaces, at least one of which is movable relative to the other wall 
surfaces to facilitate transmission of the power generated by the 
expanding fluid to an output shaft. The need for wall surfaces movable 
relative to each other introduces problems, one being associated with 
sealing between such surfaces and another being frictional losses. 
The present invention seeks to provide a rotary engine which does not 
utilise a working chamber of variable volume. In this way the invention 
seeks to limit sealing problems and frictional losses which are common 
with conventional rotary engines and internal combustion engines 
generally. 
SUMMARY OF THE INVENTION 
In one form the invention resides in a rotary jet engine comprising a 
housing having intake and exhaust zones separated from each other, a rotor 
mounted for rotation within the housing, at least one jet means for 
generating propulsive fluid from air, the jet means having an intake for 
receiving air and an exhaust outlet for ejection of the propulsive fluid, 
the jet means being mounted on the rotor whereby the thrust force thereof 
causes rotation of the rotor, the inlet of the jet means communicating 
with the intake zone and the outlet of the jet means communicating with 
the exhaust zone, and means for inhibiting fluid flow from the exhaust 
zone to the intake zone. 
The intake and exhaust zones within the housing are preferably separated 
from each other by the rotor. 
The means for inhibiting fluid flow may comprise a sealing means provided 
between the housing and the rotor. Alternatively or additionally, the 
means for inhibiting fluid flow may comprise means for generating a 
positive pressure in the intake zone as compared to the exhaust zone. The 
means for generating a positive pressure in the intake zone may comprise a 
delivery means for deliverying air into the intake zone. 
There may be a plurality of the jet means, at least one of which is mounted 
on the rotor and at least another of which is mounted on a stationary part 
of the engine. In still another arrangement there may be two 
contra-rotating rotors one of which has at least one jet means. Such jet 
means is arranged to drive the rotor on which it is mounted by its thrust 
force and to drive the contra-rotating rotor by impingement of the 
propulsive fluid thereon. In still another arrangement there may be two 
contra-rotating rotors each having at least one jet means mounted thereon. 
Each jet means is arranged to drive the rotor on which it is mounted by 
its thrust force and to drive the contra-rotating rotor by impingement of 
the propulsive fluid thereon. 
It is particularly convenient for the propulsive fluid to be heated 
atmospheric air, the heating being accomplished by any suitable means. 
With this arrangement, the jet means preferably comprises a jet burner, 
which may be of conventional form. In such a case, the atmospheric air is 
heated in the jet burner by burning a fuel within the air. The fuel may be 
a liquid hydrocarbon fuel such as power kerosene. 
It should be appreciated, however, that any other suitable means may be 
employed for heating the air, such as by some form of nuclear process. 
Preferably, the rotor is mounted on an output shaft. 
The rotor may comprise a rotor disc. The intake of the jet means may open 
onto one side of the rotor disc and the exhaust outlet may open onto the 
other side of the rotor disc. 
There may be one or more of the rotors. Where there is more than one rotor, 
the rotors may rotate in the same direction or in opposite directions. In 
the latter case, the rotor which rotates in the opposite direction to the 
output shaft may be drivingly connected thereto in any suitable way such 
as by gearing. 
Preferably, the rotary jet engine further comprises a reaction means 
against which propulsive fluid discharging from the jet means is directed 
to enhance the thrust force of the jet means. The reaction means may 
comprise a plurality of circumferentially spaced reaction surfaces such as 
vanes. 
The housing is preferably has a generally cylindrical side wall disposed 
substantially co-axially with the axis of rotation of the rotor. The 
housing may include an intake zone and an exhaust zone, the intake of the 
jet means communicating with the intake zone and the outlet of the jet 
means communicating with the exhaust zone. 
There may be a multitude of jet burners. The jet burners may be arranged in 
pairs with the jet burners of each pair disposed on diametrally opposed 
sides of the axis of rotation of the rotor.

MODES OF CARRYING OUT INVENTION 
The rotary jet engine according to the first embodiment is shown in FIGS. 
1, 2 and 3 and comprises a rotor 11 rigidly mounted onto an output shaft 
13 rotatably supported on bearings 14. The rotor 1t is accommodated within 
a housing 15 having a cylindrical side wall 17 which is co-axial with the 
axis of rotation of the shaft 13 and which defines an inner region 19. The 
cylindrical side wall 17 incorporates a manifold 21 which defines an 
annular outer region 23 which is concentric with the shaft and which 
communicates with the inner region 19 by way of an annular gap 25. A 
tangential exhaust duct 27 communicates with the manifold 21. 
The output shaft 13 extends beyond both ends of the housing 15, as best 
seen in FIG. 2 of the drawings. 
The rotor 11 comprises a disc 31 which is rigidly mounted at its radially 
inner end onto the output shaft 13 and which carries a pair of jet burners 
33. The two burners 33 are positioned on diametrally opposed sides of the 
output shaft, as can be best seen in FIG. 1 of the drawings. The disc 31 
extends through the annular gap 25 in the side wall 17 of the housing 15 
and carries a rigid sealing element 32 at its outer end. The rigid sealing 
element is disposed in very close proximity to, but is spaced from, the 
portion of the side wall 17 defining the gap 25 so as to restrict fluid 
flow through the gap. 
The rotor 11 further comprises a cylindrical rotor wall 34 co-axially and 
rigidly mounted on the output shaft 13 for rotation therewith. The 
cylindrical rotor wall 34 is, more particularly, mounted on the rotor disc 
31 and on two support elements 36 positioned on the output shaft 13 one to 
each side of the rotor disc 31. 
The cylindrical rotor wall 34 is spaced inwardly of the cylindrical side 
wall 17 of the housing 15. The two walls 17, 34 co-operate to define an 
air chamber 38 therebetween which receives atmospheric air, as Will be 
explained later. 
Each jet burner 33 is of conventional form, comprising an inlet 35, a 
combustion chamber 37, and an exhaust nozzle 39, as best seen in FIG. 3 of 
the drawings. The inlet 35 incorporates at intake funnel 40 and the 
exhaust nozzle 39 is fitted with an extension duct 42. Each of the jet 
burners is so arranged on the disc 31 that the inlet communicates with the 
air chamber 38, which constitutes an intake zone, and the extension duct 
42 extends through the annular gap 25 such that the outlet end thereof 
communicates with the outer region 23 within manifold 21, which 
constitutes an exhaust zone. 
The jet burner receives atmospheric air within the air chamber 38 through 
the inlet 35 and heats the air to generate a propulsive fluid by 
combustion of a hydrocarbon fuel. The fuel is injected into the burner by 
way of a fuel injector 43 and combustion is initiated by an ignition 
device 45. As a result of the combustion process, the air is heated and so 
expands with the result that it is ejected in the form of a jet through 
the outlet nozzle 39 into the region within the manifold 21. Air ejecting 
from the burner generates propulsive thrust which causes the rotor to 
rotate and so transmits torque to the output shaft 13. 
Reaction means 50, which comprise a plurality of reaction surfaces in the 
form of circumferentially spaced vanes 51, are provided within the 
manifold 21. The propulsive fluid jetting from each nozzle 39 impinges on 
the vanes 51, so enhancing the propulsive thrust generated by the 
propulsive fluid. The vanes 51 also serve to direct the propulsive fluid 
in a uniform manner in a direction away from the rotor, so creating a flow 
pattern which leads to the tangential exhaust duct. 
As previously mentioned, the jet burners 33 each take in air from the air 
chamber 38 within the housing 15. The propulsive efficiency of, and/or the 
thrust generated by, each jet burner can be increased by increasing the 
mass flow rate of air into the burner through the inlet 35 thereof. The 
mass flow rate of air into the burner can be increased by raising the 
pressure of air within the air chamber 38. This is accomplished in this 
embodiment by providing two blade assemblies 52 on the rotor 11, one to 
each side of the rotor disc 31. The blade assemblies 52 rotate with the 
output shaft and blow air into the air chamber 38, thereby increasing air 
pressure within the chamber. A series of stationary guide vanes 53 are 
positioned between each blade assembly 52 and the jet burners to direct 
the air uniformly towards the axially central region of the rotor and into 
the path of the intake funnels of the inlets 35 of the jet burners. 
The air delivered into the air chamber 38 to the axially central region of 
the rotor by the two blade assemblies 52 may come directly from atmosphere 
or through an air delivery system which incorporates a filter arrangement. 
The separation which exists between the air chamber 38 and the region 
defined within the manifold 21 is beneficial in that it avoids, or at 
least, limits contamination of the intake air by the propulsion fluid 
exhausted from the jet burners. This is also assisted by the positive air 
pressure which develops in the air chamber 38 by the action of the blade 
assemblies 52 during operation of the engine. 
The second embodiment, which is shown in FIG. 4 of the drawings, is similar 
in many respects to the first embodiment but each jet burner 33 is mounted 
on a separate rotor disc 31. Additionally, the jet burners are oriented so 
that the inlet 35 thereof is disposed to one side of the respective disc 
and the exhaust nozzle 39 thereof is disposed on to the other side of the 
disc. This arrangement is particularly useful as it assists in maintaining 
separation between the intake air and the propulsive fluid, thus avoiding 
or at least limiting contamination of the intake air by the propulsive 
fluid. The two rotor discs 31 serve to divide the inner region 19 into 
three sections being a central section 61 and a pair of end sections 63. 
The exhaust nozzles 39 of the burners communicate with the central section 
61 and the inlets 35 of the nozzles each communicate with a respective one 
of the end sections 63. The rotor discs 31 co-operate with the housing to 
provide a seal, or at least a flow restriction, between the neighbouring 
sections 61 and 63. 
In this embodiment, each blade assembly 52 delivers air under pressure to a 
respective one of the end sections 63 of the housing. While only shown on 
one side of the engine illustrated in FIG. 4, each blade assembly receives 
air from an air delivery system 65 which incorporates an air filtering 
means 67. 
The embodiment shown in FIG. 5 of the drawings is a simpler form of engine 
in comparison to the previous embodiments. The jet burners 33 are mounted 
on a central disc 31 and each receives air directly from atmosphere. There 
are no blade assemblies or other delivery means for delivering air under 
pressure into the region which accommodates the rotor. As with the 
embodiment shown in FIG. 4 of the drawings, the burners are disposed 
angularly so that the inlet 35 and exhaust nozzles 39 are on opposed side 
of the disc. 
The embodiment shown in FIG. 6 of the drawings is somewhat similar to the 
previous embodiments, with the exception that the jet burners 33 are 
positioned relatively closely to the output shaft 13. This has a benefit 
in that it reduces the moment of inertia of the rotor and provides for 
easier balancing of the rotor. Each inlet 35 has an elongated intake 
funnel 40 which extends to the periphery of the rotor and each exhaust 
nozzle also has an elongated extension duct 42 which extends beyond the 
disc to direct the propulsive fluid onto the reaction vanes 51. 
A rotary jet engine according to a further embodiment is shown in FIGS. 7, 
8 and 9. This engine is more compact in terms of its radial dimension than 
the engines of the earlier embodiments having an annular exhaust manifold. 
Because of its compact nature, this engine lends itself to application in 
the automotive field. The engine comprises a rotor 111 rigidly mounted 
onto an output shaft 113 rotatably supported on bearings 114. The rotor 
111 is accommodated within a housing 115 having a cylindrical side wall 
117 which is co-axial with the axis of rotation of the shaft 113 and which 
defines an inner region 119. The housing 115 has a first end wall 120 and 
a second end wall 122 at-opposite ends of the inner region 119. The first 
end wall 120 incorporates an air inlet (not shown) and the second wall 122 
co,operates with the cylindrical side wall 117 to define an exhaust outlet 
duct 124 which terminates at an annular outlet opening 126. 
The output shaft 113 extends beyond both ends of the housing 115, as best 
seen in FIG. 7 of the drawings. 
The rotor 111 comprises a disc 131 which is rigidly mounted at its radially 
inner end onto the output shaft 113 and which carries a pair of jet 
burners 133. The two burners 133 are positioned on diametrally opposed 
sides of the output shaft. 
The rotor disc divides the inner region 119 into two zones being an intake 
zone 119a which communicates with the inlet in end wall 120 and an exhaust 
zone 119b which communicates with the exhaust outlet duct 124. 
An annular sealing element 130 is provided on the cylindrical side wall 117 
in very close proximity to, but spaced apart from, the radially outer 
portion of the rotor disc 131. The rotor 131 and the and the sealing 
element 130 co-operate to restrict fluid flow between the two zones 119a 
and 119b. 
The rotor 111 further comprises a cylindrical rotor wall 134 which is 
located in intake zone 119a and which is co-axially and rigidly mounted on 
the output shaft 113 for rotation therewith. The cylindrical rotor wall 
134 is, more particularly,, mounted on the rotor disc 131 and on a support 
element 136 positioned on the output shaft 113 to the side of the rotor 
disc 131 which confronts end wall 120. 
The cylindrical rotor wall 134 is spaced inwardly of the cylindrical side 
wall 117 of the housing 115. The two walls 117, 134 co-operate to define 
an air chamber 138 therebetween which receives atmospheric air through the 
inlet (not shown) in end wall 120. 
Each jet burner 133 is of conventional form, comprising an inlet 135, a 
combustion chamber 137, and an exhaust nozzle 139. The inlet 135 
incorporates an intake funnel 140 and the exhaust nozzle 139 is fitted 
with an extension duct 142. Each of the jet burners is so arranged on the 
disc 131 that the inlet 135 communicates with the air chamber 138 in the 
intake section 119a and the extension duct 142 communicates with the 
exhaust section 119b. 
Reaction means 150, which comprise a plurality 0f reaction surfaces in the 
form of circumferentially spaced vanes 151, are provided in the exhaust 
section 119b. The propulsive fluid jetting from each nozzle 139 impinges 
on the vanes 151, so enhancing the propulsive thrust generated by the 
propulsive fluid. The vanes 151 also serve to direct the propulsive fluid 
in a uniform manner in a direction away from the rotor, so creating a flow 
pattern which leads towards the exhaust outlet duct 124. 
The vanes 151 are mounted on the cylindrical side wall 117 and extend 
radially inwardly towards a cylindrical fairing 154 which assists in 
containing the propulsive fluid and directing it towards the exhaust 
outlet duct 124. The fairing 154 is rigidly mounted on the second end wall 
122 of the housing 115 and extends across the exhaust zone 119b towards 
the rotor disc 113. A further sealing element 155 mounted on the rotor 
disc 113 co-operates with the fairing 154 to limit fluid flow between the 
rotor disc and the fairing. 
The jet burners 133 each take in air from the air chamber 138 within the 
housing 115. Air entering the air chamber 138 through the inlet in the end 
wall 120 is conveyed to the burners by way of blade assemblies 152 and 
co-operating guide vanes 153. The blade assemblies comprise are in two 
stages, comprising a first stage 156 and a second stage 158. The two 
stages progressively increase the pressure of air as it is conveyed 
through the air chamber 138 to the gas burners. The guide vanes 153 are 
mounted on the housing 115 and are also in two stages, comprising a first 
stage 160 located between the two stages of the blade assemblies and a 
second stage 162 located between the second stage of the blade assemblies 
and the rotor disc 131. 
In a further embodiment (which is not illustrated in the drawings), the 
rotary jet engine has contra-rotating rotors, each drivingly coupled to a 
common output shaft. A benefit of this arrangement is that the 
contra-rotation can eliminate, or at least minimise, gyroscopic effects. 
Each rotor has at least one jet burner and an associated reactionary means 
such as vanes. With this arrangement, the jet burner on each rotor can 
propel both of the rotors. The rotor which carries each jet burner is 
propelled by virtue of the propulsive thrust generated by the jet burner. 
The jet burner is also arranged to direct the propulsive fluid expelled 
from it onto the reactionary means of the other rotor. This propulsive 
fluid impinging on the other rotor causes it to rotate. 
In a still further embodiment (which is also not shown), the jet burners 
are mounted on a stationary part of the engine and are so arranged that 
the propulsive fluid ejected by the jet burners impinges upon the rotor 
thereby causing it to rotate. The rotor is provided with reactionary 
surfaces such as vanes against which the propulsive fluid can impinge to 
produce the rotation. 
While rotary jet engines according to the various embodiments have been 
described as operating on liquid hydrocarbon fuel, it will be appreciated 
that any suitable form of fuel can be employed for heating of air to 
generate the propulsive fluid. 
A liquid hydrocarbon fuel is, however, a convenient form of fuel and it may 
be delivered to the jet burners by way of delivery lines 70 (see FIG. 10) 
which extend along the output shaft 13 of the engine. At locations where 
the output shaft is rotatably supported on the bearings 14, tunnel sleeves 
71 are provided through which the delivery lines 70 can pass. Each tunnel 
sleeve comprises a sleeve element 73 having one or more axial bores 75 
through which the delivery lines can extend. 
From the foregoing, it is evident that the various embodiments provide a 
rotary jet engine which is of relatively simple construction in comparison 
to many conventional engine designs. 
Although the invention has been described in relation to several specific 
embodiments, it should be appreciated that it is not limited thereto and 
that various alterations and modifications may be made without departing 
from the scope of the invention.