Propelling nozzle for the thrust vector control for aircraft equipped with jet engines

The proposal is for a thrust nozzle for aircraft fitted with jet engines especially for lateral thrust vector control, in which the upstream ends of at least two flaps (8, 12) actuated via lever-like adjusters are arranged to pivot simultaneously at different angles of rotation about spindles running across the nozzle axis (20) and between walls (22, 23) running substantially parallel to the nozzle axis of a square nozzle housing in such a way that, with a permanently convergent nozzle contour, a narrowest cross-section is formed between the flaps (8, 12) at the outlet side; one end of each lever-like adjuster (28, 29) is to engage in downstream ends of the flaps, said adjusters being arranged at their movably mutually coupled other ends to travel in a guide path (30) which is curved so as to produce continuously different flap rotation angles; one or more narrowest cross-sections can either be kept continuously constant or change dependently upon the jet deflection angle.

BACKGROUND AND SUMMARY OF THE INVENTION 
The invention relates to a propelling nozzle for aircraft equipped with jet 
engines, and particularly for lateral thrust vector control. 
Under the name of "Stealth Bomber B-2", an aircraft which is to be largely 
insensitive to radar and infrared detection is known, for example, from 
the German Publication DE-Z Fluo Revue, No. 1, January 1988. For the 
predominant part, the aircraft consists of a relatively far projecting 
wing unit with fuselage as well as pay load receiving structures 
integrated into it. For this purpose, by means of tunnel-type air inlets 
projecting out of the top sides of the wing surfaces, fanjet engines are 
to be supplied with air which are arranged in the wing structure in a 
physically inwardly and downwardly retracted manner. In other words, the 
known case involves a subsonic aircraft concept also because, in order to 
limit heat emissions resulting from the thrust jet, the thrust jet is a 
mixture of a hot core jet, relatively high parts of fan air -and 
additionally taken-in boundary layer air. This is in contrast to 
conventional aircraft which are designed for supersonic flight, are 
constructed as combat aircraft or as arms carriers and can be detected 
relatively easily by, among other devices, infrared sensors, and in the 
case of which often gas turbine jet engines with a relatively low bypass 
flow ratio are used in combination with an afterburning system 
(afterburner) which can be switched on, for example, for the supersonic 
flight operation. 
From the German Patent Document DE-PS 11 44 117, a jet deflection 
arrangement is known which can be used, in particular, for vertical 
take-off aircraft and which consists of pipe bend segments which can be 
pivoted in a telescopic manner, in combination with an additional jet 
directing cascade that is situated in the pipe bend segment which can be 
moved the farthest to the outside and that consists of rotary blades which 
can each be pivoted simultaneously about respective central axes. The 
remaining jet deflection which is the result of such a jet directing 
cascade construction and arrangement is connected with a still 
considerable throttling effect as well as deflecting losses of the exhaust 
gas jet with the corresponding repercussions on the engine. The telescopic 
movability of the pipe bend segments is comparatively complicated and not 
free of susceptibility to trouble (thermally caused pipe warping). Also, 
in the known case, a response action for a thrust vector control should be 
expected that is relatively slow with respect to time. 
From the German Patent Document DE-GM 70 08426, a thrust jet coupling 
arrangement is known in which deflecting blades arranged in the manner of 
a deflecting cascade are to each consist of a fixed inlet section and 
individual sections which can be pivoted on it continuously in order to 
thus try to eliminate the disadvantage of the already discussed throttling 
effect on the engine. It is a prerequisite for the implementability of the 
known case that corresponding multi-member deflecting blades with their 
respective first rotating shafts are arranged in the area of a diagonally 
cut outlet plane of a housing wall end. With respect to an axially 
symmetrical oncoming flow, no jet deflection or thrust vector control is 
possible in the known case which takes place on both sides of this 
oncoming flow in a plane, that is, toward one direction and to a direction 
that is opposite to it. On the whole, between the deflecting blades, no 
constant outlet cross-section or narrowest cross-section in the sense of a 
"convergent nozzle", which always accelerates the flow, is made available 
in the outlet plane. The adjusting expenditures and the degree of 
susceptibility to disturbances with respect to linkages between the 
individual blade segments are relatively high. 
A propelling nozzle according to the initially mentioned type is known from 
the U.S. Pat. No. 3,640,469. In this known case, it is assumed that three 
flaps exist which are arranged at the same mutual distance in the plane 
containing the axes of rotation. In this case, the three flaps are to be 
actuated by way of a comparatively complicated multiple lever and link 
arrangement which partly operates in a manner of a gearing. In this case, 
each outer flap is non-rotatably connected with a separate actuating lever 
extending in the longitudinal direction of the flap. At the respective 
rearward end, the actuating levers are coupled with the one end of links. 
At the other end, these links are pivotally coupled at an upstream point 
with a rocking lever which is pivotable about a downstream housing point. 
At an arm, which laterally projects out of the rocking lever and is 
fixedly connected with it, one end of another swivel arm is to be linked 
which is coupled by means of its other end to the downstream end of 
another actuating lever. At its other end, this actuating lever is 
non-rotatably connected with the center flap of the propelling nozzle on 
the side of the axis of rotation. In the known case, the adjusting force 
is to be introduced approximately in parallel to the nozzle axis into the 
laterally projecting arm of an actuating lever (double-armed lever) which 
is part of an outer nozzle flap. In the known case, while all flaps are 
controlled simultaneously, a torsion of the rocking lever takes place 
which is converted to a central differential-angle control of the center 
flap with respect to the outer flaps. In the known case, it is virtually 
not possible to be able to control either only two (outer) flaps or more 
than three flaps in a blade cascade-type manner, in each case, by 
different torsional angles. The reason is that, particularly in the latter 
case, it is necessary to be able to locally control larger or smaller 
thrust jet deflections between two adjacent flaps. In the interest of 
locally reduced deflecting losses (locally relatively abrupt deflection by 
way of two flaps of the cascade), it is therefore required to make 
available correspondingly larger dimensioned local nozzle surface 
cross-sections and, at the same time, in turn, maintain the required 
nozzle convergence between two flaps. For this purpose, the known case 
furnishes no tangible starting point to a solution because it aims 
exclusively at a constant-surface convergent nozzle construction along the 
whole deflecting range in the case of thrust vector control. In addition, 
in the known case, by means of the above-described gearing-type control 
lever configuration (different lengths of the additional swivel arm and of 
the additional actuating lever: in this case, center flap), while the 
flaps are controlled at the same time, deflecting angles of various sizes 
of the center flap are obtained, while it is pivoted toward the one or 
toward the other side as well as relatively with respect to the control 
positions of the two outer flaps, so that the laws endeavored in the known 
state of the art (keeping the outlet surface constant) cannot be carried 
out in practice. In other words, the individual degree of freedom for a 
locally varying flap pivoting is estimated to be very low. The latter 
applies particularly if the thrust-vector control of the air exhaust gas 
systems of several engines by means of a cascade-type nozzle system is 
involved. In addition, in the known case, in view of the flap control, 
relatively large stress moments are to be expected which affect the 
control system. Also, the known case can probably be implemented only by 
means of relatively thick-walled and heavy flaps which have a shape that 
tapers in a wedge shape from the direction of the respective pivot 
bearings. In the known case, the total of the control device expenditures 
is relatively high which is accompanied by an increase in weight. 
The above-discussed known nozzle or jet deflecting concepts provide no 
information concerning a development and an arrangement with respect to a 
reduced radar and/or infrared detection. These known deflecting concepts 
also do not concern the problem of processing, in each case, the thrust 
jets of two or several jet engines in the manner of nozzles and for the 
purpose of a 2-dimensional thrust vector control in such a manner that, on 
the nozzle side, a risk of being detected by radar or infrared detection 
is as low as possible. 
The invention is based on the object of providing a controllable propelling 
nozzle which is suitable for an initially mentioned type of aircraft and 
which permits a 2-dimensional thrust vector control, while the flap 
control is as fast as possible, with relatively low control device 
expenditures, without causing in variable positions impermissible 
deflecting losses and throttling of one or several exhaust gas flows. 
The mentioned object is achieved by a propelling nozzle for aircraft 
equipped with jet engines, particularly for the lateral thrust vector 
control, in the case of which at least two flaps actuated by way of 
lever-type control members are arranged at their upstream ends to be 
pivotable about pivots extending transversely with respect to the nozzle 
axis, said flaps being disposed as well between walls of a square nozzle 
housing extending essentially in parallel to the nozzle axis, said flaps 
being simultaneously pivotable about different twisting angels in such a 
manner that--while the nozzle contour course is always convergent--an 
exit-side narrowest cross-section is formed between the flaps, 
characterized in that the ends of one side of the lever-type control 
members are applied to downstream flap ends, the control members being 
arranged at the level of their other ends movably coupled with one anther 
so that they can be moved in a track which is connected to be curved for 
simultaneously always forcing different flap twisting angles. 
The invention permits the providing of a nozzle concept, which is 
convergent in all flap positions, and by means of which exhaust-gas fan 
air jet mixtures delivered by one or several engines, particularly for the 
purpose of a variable lateral control of an airplane, can be carried 
through with extremely low aerodynamic losses. In the area of the fuselage 
end and/or the wing end, particularly in the case of an aircraft of the 
initially mentioned type, the propelling nozzle may be constructed to be 
extremely flat (low installation height) and, because of the comparatively 
short flap lengths, can be constructed to be comparatively short, which, 
in turn, has a favorable effect with respect to a comparatively light 
weight of the nozzle. 
In the case of the present propelling nozzle, it is therefore ensured that 
the geometrically narrowest cross-section which can be adjusted in each 
case between two flap ends according to the requirements, is situated at 
the nozzle end and --while avoiding deflecting losses--no flow-through 
changing repercussions occur on the inside nozzle flow which, in turn, 
could endanger the engine operation. Even with only two flaps, it is 
possible to either make available an always convergent nozzle with an 
always constant narrowest cross-section or an always convergent nozzle 
with a nozzle surface cross-section or narrowest cross-section which 
increases as a function of an increasing jet deflecting angle. 
According to the invention, advantageously a blade cascade-type multiple 
flap nozzle may be provided in the case of which a medium or central 
nozzle flap defines the required or nominal or maximal jet deflecting 
angle. In view of the after expansion of the carried-through gas flows 
behind the respective narrowest nozzle cross-section, a possibly resulting 
slight reduction of the required jet deflection can be compensated by a 
more pronounced angular incidence of outer flaps relative to the position 
of the corresponding center nozzle flap. 
The designability of the propelling nozzle (flat long-drawn-out rectangular 
cross-section) which, particularly when several nozzle flaps are used, in 
a blade cascade-type manner, is extremely flat, reduces the danger of 
detection with respect to infrared sensors, particularly in combination 
with an--according to the invention--backwardly and downwardly sloped 
nozzle outlet or with respect to the inclined installing position of the 
engine or engines in the or on the aircraft. 
The propelling nozzle according to the invention may also be used for the 
jet deflection or the thrust jet pivoting in a vertical or perpendicular 
plane, for example, in the case of two jet engines arranged above one 
another. 
Other objects, advantages and novel features of the invention will become 
apparent from the following detailed description of the invention when 
considered in conjunction with the accompanying drawings.

DETAILED DESCRIPTION OF THE DRAWINGS 
In FIG. 1, reference number 1 represents the combined wing --fuselage 
structure of an initially discussed aircraft which is to be insensitive to 
a very large extent to the enemy's radar and infrared detection. Reference 
number 2 represents a variant of a propelling nozzle according to the 
invention which, in this case, in view of a propulsion arrangement of the 
aircraft, is arranged and constructed with two turbojet engines 3, 4 
arranged in parallel next to one another. In this case, the propelling 
nozzle 2 is arranged symmetrically with respect to the longitudinal 
symmetry plane 5 of the aircraft with the outlet ending at the 
wing--fuselage end; in this case, for example, between two additional 
ailerons 6, 7 of the aircraft. In the present case, the propelling nozzle 
2 is constructed in the manner of a cascade and consists, among other 
things, of five flaps which are arranged at uniform distances from one 
another from one side to the opposite side and are consecutively numbered 
8, 9, 10, 11 and 12. The flaps are pivotally disposed in a plane 13 which 
in this case is arranged at a right angle with respect to the longitudinal 
symmetry plane 5. The flaps 8 to 12, for the purpose of the thrust vector 
control, should be arranged to be simultaneously pivotable about different 
pivoting angles and operable in such a manner that a narrowest 
cross-section of the propelling nozzle constructed on the nozzle outlet 
side is maintained to be always constant. In the present case, the 
propelling nozzle 2 is in the level flight or straight-ahead flight 
position (also see FIG. 9). Additional jet deflecting angle variations 
will be discussed and described in detail in FIGS. 10, 11 and 12. 
FIG. 2 clearly shows the engine and propelling-nozzle installation position 
which is slightly inclined from the front top to the rear bottom, in this 
case, illustrated on the jet engine 4 which is on the left in FIG. 1, thus 
by the sloping of the engine axis A with respect to the longitudinal 
aircraft axis G. 
FIGS. 3 and 4 show more clearly than FIG. 1 the 
engine-exhaust-gas-flow-side pipe line geometry by means of which the mass 
flows of fan air flows and respective hot-gas residual flows delivered by 
the two jet engines 3, 4 are to be supplied to the respective propelling 
nozzle 2, specifically with deflecting losses of the mass flows that are 
as low as possible. On the outlet side, the two jet engines are in this 
case followed by two pipe bends 14, 15 by means of which the flow is 
deflected here by approximately 30.degree.. Pipe lines 16, 17, which are 
connected to the pipe bends 14, 15 and have respective straight 
longitudinal axes, end at respective identical angles of slope 
symmetrically against the propelling nozzle 2. It is clearly illustrated 
in FIG. 4 and elsewhere that the pipe lines 16, 17 change from an at first 
circular cylindrical cross-section to a cross-section which is rectangular 
on the nozzle-connection side. By means of their outlet ends, the two pipe 
lines 16, 17 are connected to two pipe-type inlets 18, 19 which have a 
rectangular cross-section and which have a slightly opposite bend to the 
pipe bends 14, 15. As also illustrated in FIG. 3, the pipe-type inlets 18, 
19 are symmetrically guided together in the manner of a housing by means 
of their directly adjacent lateral walls S1, S2. At the meeting point as 
well as approximately in the plane 13, in which the flaps 8 to 12 are 
pivotally disposed, a housing section 21 is connected which contains the 
flaps. The respective rectangular double-pipe ends of the two pipe-type 
inlets 18, 19, at the end-connection-side, may be constructed in the 
manner of a frame as well as supports of the, in this case, upper and 
lower walls 22, 23 of the nozzle housing which are disposed opposite one 
another (FIGS. 4 and 8). On as well as between the two walls 22, 23 (in 
this case, on the frame side--R--FIG. 8), the flaps 8 to 12 are pivotally 
disposed in the plane 13, specifically by means of pivots (see in this 
respect: pivots 24 of the one flap 12 which is on the outside in this 
case--FIG. 8). 
A respective forward articulated-lever-type cabin-side suspension of the 
mentioned propelling system according to FIGS. 1, 3, and 4 is marked by 
the letter V; an identical or comparable rear suspension is marked by the 
letter H (here, on the frame side on R--FIG. 8), and a thrust pin is 
marked with the letter S. 
Depending on the number of the engines, the respective propelling nozzle 
therefore contains at least one pipe-type inlet which, in turn, is a 
component of the nozzle housing. As a modification of FIGS. 3, 4, 7 and 8, 
the pipe-type inlet or inlets may also be constructed to be square or even 
as transition pipes which change from an initially, for example, still 
circular cross-section to a, for example, rectangular cross-section, 
specifically on the end side and connection side at the corresponding 
housing section 21 of the propelling nozzle which contains the flaps. 
According to the number of and the distances between the engines, the 
pipe-type inlets, thus also those 18 and 19 according to FIGS. 1, 3, 4, 7 
and 8, may also be constructed with a straight axis as well as with 
straight walls. A respective propelling nozzle variant with, for example, 
three jet engines arranged next to on another will be discussed in detail 
in connection with FIG. 13. 
The construction and arrangement of the propelling system of the aircraft 
illustrated particularly in FIGS. 1, 2 and 4, in an adaptation to the jet 
engines 3 and 4 arranged here with a relatively large lateral distance, as 
well as in combination with the pipe feeder system 14, 15, 16, 17 together 
with the nozzle-housing-side inlet construction 18, 19, permits an 
arrangement of the propelling nozzle 2 which is physically retracted 
toward the center as well as toward the rear and downward. In particular 
with respect to heat emissions and the resulting danger of infrared 
detection, a solution is found that is insensitive to being recognized not 
only with respect to the arrangement of the jet engines 3,4 but also with 
respect to the propelling nozzle construction itself; in this case, 
particularly also with respect to the propelling nozzle 2 and its upper 
rearward or obliquely rearward viewing possibility. A contributing factor 
to the insensitivity of the propelling nozzle 2 as well of the whole 
propelling system to heat emission is that, according to the invention, 
jet engines 3, 4 are provided as fan engines which have relatively large 
bypass flow ratios. According to the cut-open jet engine 3, this is, for 
example, a twin-shaft turbofan engine in which the fan 24, as the front 
fan, delivers into a secondary air duct 25 shrouding the basic engine; 
that is, the main propulsion thrust is made available by the fan 24. The 
propelling nozzle 2 is therefore in each case acted upon by a gas mass 
flow which predominantly consists of relatively cold fan air parts (arrows 
F) as well as hot gas parts (arrows Hg) of the basic engine which are 
discharged from the low-pressure turbine 26 (=driving turbine of the fan 
24), together with gas generators. As also illustrated on the jet engine 
3, a mixer M for the fan air parts and hot gas parts F and HG is provided 
which is constructed of surrounding pocket-type recesses so that a 
relatively low exhaust gas temperature is present already at the outlet 
side at the engines 3, 4 which is clearly reduced until reaching the 
propelling nozzle 2, specifically to temperature values of approximately 
200.degree. C. Thus, the propelling nozzle 2 can completely or 
predominantly be constructed in a "light construction", for example, from 
aluminum or an aluminum alloy. The temperature level of the respective 
pipe feeders to the propelling nozzle 2 as well as also the latter itself 
may therefore be estimated to be relatively low with respect to heat 
emissions (danger of infrared detection). In addition, according to the 
invention, there is the possibility to provide a flow surrounding the 
whole propelling system, particularly the pipe lines and the propelling 
nozzle itself in the manner of a cooling film, specifically by means of 
air boundary layer flows taken in in the vicinity of the engine inlets. 
Particularly FIGS. 1, 3 and 7 also show that the housing section 21 of the 
propelling nozzle 2 in which the flaps 8 to 12 are arranged pivotally 
between the mutually opposite walls 22, 23, from the inlet side to the 
nozzle outlet side, is physically expanded in an adaptation to the maximal 
outer angular deflection of a respective outer flap 8 or 12. In this case, 
also see FIG. 12, maximally possible angular deflection of the one outer 
flap in the case of a resulting maximal jet deflection of in this case for 
example, 25.degree. is feasible. To this extent, this local expansion of 
the housing section 21 results in relatively low aerodynamic losses with 
respect to the outer air flow, since basically only the respective upper 
and lower walls 22 or 23 in this case (FIG. 4 and 8) are affected by it. 
This therefore takes place by means of a propelling nozzle configuration 
in which the housing section 21 between the walls 22 and 23 is 
predominantly open not only at two sides which are opposite one another 
with respect to the pivot plane (in this case, for example, horizontal), 
but also in the direction of the nozzle outlet side; that is, in this 
case, in sections, is blocked off only by means of the respective outer 
flaps 8 and 12 on the hot-gas side with respect to the outer surroundings. 
The above-mentioned construction may also be described by stating that, on 
a rectangular, essentially frame-type end section R (FIG. 8), ends of the 
mutually opposite walls 22, 23 are arranged or constructed which project 
freely in parallel to the nozzle axis and between which the flaps 8 to 12 
can be pivoted. 
However, the above-mentioned characteristics of the invention, in 
principle, do not exclude that the whole nozzle housing or the housing 
section 21 may be constructed to be closed off by itself in a square or 
rectangular manner. 
In this case, a respective outer flap 8 and 12 may, at the same time, be 
constructed as a sealing device for the hot-gas flow guided between them 
with respect to the outside environment. 
Advantageously, in this case, the respective outer flaps 8 and 12 may be 
arranged to be sealed off in the plane of the rotating axis with respect 
to adjacent pipe wall ends and/or guide wall ends as well as along the 
flap edges bordering on the walls 22, 23 of the nozzle housing section 21 
by means of rigid, elastic or movable sealing devices. Preferably, brush 
seals may be used in this case. The use of a sealing device made of rubber 
or the like or in the form of teflon cords is also conceivable. 
The above-discussed characteristics of the invention can analogously also 
be applied to the now discussed propelling nozzle variants according to 
FIGS. 5 to 6 and may also analogously be used in the case of the latter. 
The propulsion and control system discussed in connection with FIGS. 5 to 
6, in turn, can be analogously applied to the embodiment particularly 
according to FIG. 7. 
Thus, according to FIGS. 5 to 6, the propelling nozzle according to the 
invention may also be used or practiced advantageously in an assignment to 
an individual jet engine for the purpose of a variable thrust vector 
control. For this purpose, the propelling nozzle consists, for example, of 
a rectangular pipe inlet 27, at the frame-type end part R of which (also 
see, for example, FIG. 8), the sections of the mutually opposite walls 22, 
23 of the nozzle housing which project in parallel to the nozzle axis 
(axis 20) are to be connected in this case also. FIGS. 5 to 6, in this 
case, only show the one section of the wall 22 which is on top here and is 
part of the housing section 21. Within the framework of these basic 
constructions of the propelling nozzle according to the invention, there 
are therefore, in the respective plane 13, the position of which coincides 
with the connection-side connecting plane between the inlet and the 
housing section 21, only two flaps 8 and 12 arranged at a distance and 
pivotal about vertical pivots (Points P1 and P2) and at the same time 
about different twisting angles. The two flaps 8 and 12, at the same time, 
carry out the initially (see, for example, FIGS. 1, 3 and 7) noted 
function of the "outer flaps", among other things, also with respect to 
their sealing effect. 
As also shown clearly in FIGS. 5 and 6, the two flaps 8 and 12, on the 
hot-gas as well as ambient-air side, are arranged, aerodynamically 
advantageously flush with the surfaces, in alignment with their upstream 
ends, on circularly cylindrically recessed surfaces of the frame-type end 
part R of the two lateral walls of the pipe-type inlet 27. In other words, 
the flaps 8 and 12, in each case being aerodynamically aligned flush with 
the surfaces, connect to the ends of the two mutually opposite lateral 
walls of the inlet 27. 
In this case, the respective solid lines indicate the straight-ahead or 
level flight position of the flaps 8 and 12 (first end position or basic 
position). The position of the two flaps 8 and 12, which is indicated by 
the interrupted line, represents a second joint end position of both flaps 
8 and 12 with resulting maximal jet deflection (arrow Re) toward one side 
(rear--right). A third end position of both flaps 8 and 12, which is 
indicated by an interrupted line and is covered by cross-hatching, 
represents the resulting maximal jet deflection (arrow Rl) toward the 
other side (rear--left). In all end positions mentioned as examples, a 
narrowest cross-section, which is maintained constant, exists between the 
flaps 8 and 12 while the nozzle construction is always convergent. 
FIG. 5 also illustrates clearly that for the second joint end position of 
the flaps 8 and 12 (arrow Re), the one flap 8 must be controlled out of 
the original straight-ahead flight position, at the same time, about a 
larger flap twisting angle .alpha. than the other flap 12 (twisting angle 
.beta.) while, for the third joint end position (arrow Rl), the existing 
conditions are exactly reversed; that is, flap 12 must be controlled or 
pivoted by a larger pivoting angle .alpha.' than flap 8 (twisting angle 
.beta.'). The aspects that were previously mentioned and noted with 
respect to FIG. 5 analogously also apply in connection with the propelling 
nozzle variant according to FIG. 6. 
In order to be able to swivel the flaps 8, 12 (FIG. 5) in the indicated 
manner, for the purpose of a jet deflection and a thrust vector control, 
at the same time, by different pivoting angles, lever-type control members 
28, 29 are provided which are schematically represented by corresponding 
lines and which, in this case, for example, by means of their one ends 
(Points A1, A2) are applied in an articulated manner to the downstream 
ends of the flaps 8, 9. By means of their other ends, which are movably 
coupled to one another (lever hinge point A3), the lever-type control 
members 28, 29 can be moved in an assigned track 30 which in this case is 
also indicated only by a line and which, in an adaptation to the required 
flap control--particularly the simultaneous control about different 
pivoting angles--is curved. In this case, the track 30 is arranged to 
extend essentially transversely to the nozzle axis 20. In particular, in 
this case, the track 30 is curved uniformly on both sides by being arched 
out toward a joint nozzle symmetry point. In this case, this nozzle 
symmetry point coincides with the position of the lever hinge point A 
which the latter takes up when the propelling nozzle together with the 
flaps 8, 12 is in the straight-ahead flight position which previously had 
also been defined as the first end position or basic position of the 
propelling nozzle. In a manner that is not shown in FIG. 5 but is 
analogously clearer in FIG. 7, the lever-type control members 28, 29 may 
be movable or positively guided on or at the level of the joint linking or 
hinge point A3 by means of a roller or the like in the track 30 which, for 
this purpose, must be constructed to be of a connecting-link type. 
Hydraulically or pneumatically operated control cylinders 31 (FIG. 5) or 
31, 32 (FIG. 8) may be provided as the driving systems for the flap 
control. However, the use of other, for example, motor-driven operating 
devices, such as ball caster spindles, is also easily possible. According 
to FIG. 5, a control cylinder 31 is therefore indicated which is fastened 
to the downstream end of the nozzle housing, in this case, therefore, a 
control cylinder 31 which is fastened in Point B laterally movably on the 
outside to the upper wall 22 and which, by means of its 
tension-compression-rod-type control member 33, at the level of the one 
flap-end-side lever hinge point A1, is movably coupled to the one flap 8. 
When the one flap 8 is controlled, the other flap 12 is therefore pivoted 
along at the same time by way of the described control lever system 28, 29 
together with the track 30, while complying with the law of different flap 
twisting or swivel angles in the manner of the resulting variable thrust 
vector control possibilities. 
It is advantageous for the lever-type control members 28, 29 interacting 
with the flaps 8 and 12, the tracks and possibly including the control 
cylinders 31 (FIG. 5) or 31, 32 (FIG. 8) to be arranged outside the nozzle 
hot-gas flow and thus in a manner that is unimpaired by it and without any 
aerodynamic impairment of the hot gas flow. 
Deviating from the embodiment, for example, according to FIG. 5, it would 
definitely be possible within the scope of the invention, among other 
things, in view of the existing installation and mounting conditions, to 
arrange the driving devices for the flap control, therefore the control 
cylinder 31, in such a manner that the outer end of the pertaining control 
member 33 is applied in Point A 3 or at the level of this Point A 3 (lever 
hinge point or lever linking point) 
Within the scope of the invention, there is, for example, deviating from 
FIG. 5, the possibility that, particularly in view of a construction of 
the driving systems as control cylinders 31, they may be arranged either, 
according to FIG. 5, downstream or upstream of the respective track 30; 
here, for example, in the case that the corresponding control member 33 
should be coupled to a flap, such as 8, on the end side, for example, in 
the central area. 
It is advantageous to also provide according to the invention that the 
control cylinders 31 (FIG. 5) or 31, 32 (FIG. 8) be arranged angularly 
offset with respect to one another by 180.degree. laterally outside on the 
upper and lower wall 23 and 24 of the respective housing section 21. In 
this case, the second or lower control cylinder 32, which is not visible 
in FIG. 5, with its tension--compression-rod-type control member, would on 
the end side be applied to the other flap 12 in a hinged manner with the 
assignment of relevant lower level control kinematics together with the 
track. This arrangement permits a uniform distribution of the weight and 
also has an advantageous effect with respect to a uniform control force 
introduction. Also if a control cylinder should fail, such as 31, the flap 
control would still be ensured by way of the other control cylinder, such 
as 32. 
FIG. 6 represents another modification with respect to FIG. 5 basically 
only as a result of the fact that a propelling nozzle exists which is 
axially shortened in its overall length with respect to the housing 
section 21, while the flap length according to FIG. 5 is maintained. 
Downstream of the nozzle housing opening or of the end of the wall 22, 
which is on top here, a control cylinder 31 together with the 
tension-compression-rod-type control member 33 is arranged on it, the 
control member 33 being hinged on the end side to one 8 of the two flaps 8 
or 12 which project out of the housing opening. According to FIG. 6, there 
is therefore, with respect to FIG. 5, a position of the track 30 as well 
as of the lever-type control elements 28, 29 which is displaced farther to 
the rear in the direction of the nozzle outlet, the control elements 28, 
29 therefore, on the housing side, partially hanging over freely toward 
the rear. Otherwise, the method of operation of the propelling nozzle 
concept according to FIG. 6 is virtually identical to that according to 
FIG. 5. The reduction of the installing length, a reduction in weight as 
well as a construction without guide slots are further advantages of the 
propelling nozzle construction of FIG. 6 in comparison to FIG. 5. 
As discussed, by the way, initially in connection with FIGS. 3, 4 as well 
as 7 and 8, the propelling nozzle configurations according to FIG. 5 and 6 
are also to be constructed in such a manner that the mutually opposite, 
here therefore upper and lower walls 22 and 23 of the housing section 21 
in which the flaps 8, 12 are arranged so that they can be completely or 
predominantly pivoted, in an adaptation to the flap sloping course 
resulting from the maximal angular deflection (see .alpha., .alpha.'--FIG. 
5) of one 8 or the other flap 12, are physically expanded, specifically 
from the inlet side in the direction of the outlet side of the housing 
section 21. 
In regard to the initially discussed propelling nozzle 2 in the 
cascade-type multiple flap arrangement, FIG. 7 illustrates clear 
individual details also with respect to the control kinematics and the 
appropriate special track construction. Particularly, as a modification of 
the "basic construction" according to FIG. 5, FIG. 7 provides that the 
lever-type control members--viewed in sequence from one side of the 
propelling nozzle to the other side--marked with references numbers 29, 
28, 29' and 28' are coupled with one another in an articulated, 
accordion-type manner. With respect to the one joint lever linking or 
hinge points A3, A3', the corresponding lever-type control members 29, 28 
and 29', 28', as an accordion-type lever connection, by means of rollers 
37, 38 arranged at the level of Points A3, A3', therefore engage in 
assigned sections of a track 30' which in regard to the respective flap 
twisting angles, which at the same time are to be achieved in a different 
manner, extends alternately in a straight line as well as continuously 
sometimes to one or the other side in a differently arched manner. By 
means of their other or remaining ends, for example, the lever-type 
control members 28, 29' are movable also on joint linking or hinge points 
A 4 coupled to one another. At the level of hinge point A4, the downstream 
end of the flap 11 is linked by way of a pin so that it can be taken 
along. The downstream end of the here central flap 10 is applied to the 
remaining or other end of the lever-type control member 28' by way of a 
pin so that it can be taken along. The same applies analogously with 
respect to the other or remaining end of the lever-type control member 29 
and the coupling with the here one outer flap 12 so that it can be taken 
along. In this case, the pins which are situated on the downstream flap 
ends are guided through the, in this case, upper wall 22, as an outer 
lengthening, by means of flap-pivot concentric slots 39, 40, 42. 
Advantageously, the track 30' forms an additional wall reinforcement which 
extends on the outside on the here, for example, upper wall 22 
transversely with respect to the nozzle axis 20. The control cylinder, 
which in this case is on top, again is marked with the number 31. Its 
pertaining tension-compression-rod-type control member 33, in this case, 
by means of its free end, at the level of Point A5, at least indirectly by 
way of the corresponding pulling pin, is movably coupled with the 
downstream end of the central or center flap 10 as well as also with the 
end located there of the lever-type control member 28'. As illustrated in 
FIG. 8, on the bottom and on the outside, that is, therefore, on the 
respective lower wall 23, the same control kinematics with the drive may 
be provided. This also applies in connection with the other propelling 
nozzle half of FIG. 8 represented as an interior view. For each nozzle 
half, at least two control cylinders 31 and 32 (FIG. 8) are provided. 
According to FIG. 8, with respect to the lower wall 23, outside, the 
pertaining control cylinder has the reference number 32, a lever-type 
control member which is relevant with respect to 29 (top), has the 
reference number 29''; and the roller, which is closest to it, together 
with the section of the track, have the reference number 37' and 30''. 
According to FIG. 7, the pipe-type inlet 18, 19 have guide walls 43, 44 
constructed as flow dividers which, at the same time, form local pipe 
reinforcements. According to the right-hand propelling nozzle half 
(interior top view), for example, the flaps 8, 9 and 10 in the plane 13 in 
which they are pivoted, are therefore consecutively directly pivotally 
connected, in a wall-surface-flush manner with low aerodynamical losses, 
behind the one outer lateral wall SO, the guide wall 43 and the meeting 
point S3 (from S1 and S2). Naturally, this applies analogously also with 
respect to the remaining flaps 11, 12. Reinforcing struts, such as 44', 
45, which extend in the longitudinal direction of the housing, may in each 
case be provided on the outside on the upper and lower wall 22 and 23 of 
housing section 21 or of the pipe-type inlets, such as 19, in which case, 
the one strut 44' is at the same time a holding device for the control 
cylinder 31 which is, for example, movably anchored on it in Point B. 
In particular, FIG. 8 also shows that the combined drive adjusting and 
guiding systems are enclosed by outer housings 46, 47 so that they are 
tight with respect to the environment. Such or similar housings or housing 
enclosures may analogously also be provided in the case of the already 
described propelling nozzle variant according to FIG. 5. 
As another advantageous result of the above-described arrangement of the 
propelling system of the aircraft according to FIGS. 1 and 3, FIG. 9 shows 
the possibility of utilizing a specific space 48, for example, for 
droppable loads, between the two jet engines 3, 4 and locally in front of 
the propelling nozzle 2. In addition, FIG. 9 illustrates the basic or 
initial representation of the propelling nozzle for the straight-ahead 
flight. As far as required, details which were already described and 
illustrated in FIGS. 1, 3, 4 as well as 7 and 8, in FIG. 9 and also in 
FIGS. 10, 11 and 12 have again received the same reference numbers. In 
FIG. 9, line L represents the central or resulting jet deflection angle, 
in this case, zero, from the sum and the respective flow-off direction of 
the individual thrust jets carried through between the individual flaps 8, 
9 and 9, 10 and 10, 11 and 11, 12, which, in the mentioned flap sequence, 
are indicated by the respective central streamlines L1, L2, L3 and L4 and 
which, in this propelling nozzle end position (straight-ahead flight) all 
meet in a Point SM on the Line L. The position of the medium or central 
flap 10 is therefore representative of the central or resulting jet 
deflecting angle. In this case, Line L (FIG. 9) is situated on the or as 
an extension of the longitudinal symmetry plane 5 or the longitudinal axis 
of the aircraft. 
According to FIG. 9, an individual jet course therefore exists according to 
Lines L1 to L4 which--viewed from the Point SM--is expanded in the manner 
of a fan in the direction of the nozzle end. The relevant cross-sectional 
surfaces assigned to the latter between the flaps 8, 9 and 9, 10 and 10, 
11 and 11, 12 are consecutively marked Q1, Q2, Q3 and Q4. According to 
FIG. 9 and corresponding to the invention--viewed from the central flap 10 
or from the inside toward the outside--the nozzle flaps 8, 9 and 11, 12 in 
the corresponding plane 13, are arranged in each case with an increasing 
angular setting relative to a parallel line to the nozzle axis and to a 
respective pertaining parallel line relative to the symmetry axis 5, which 
in an analogous assignment is indicated by the angles of slope 
.gamma.1-.gamma.4 of the lines L1 and L4 with respect to line L as well as 
by the angles of slope .phi.2 -.phi.3 of lines L2 and L3 with respect to 
Line L. 
According to FIG. 9, corresponding to the invention, the individual 
cross-sectional surface Q1, Q2, Q3 and Q4 are selected such--that is, 
Q3=Q2 and Q1=Q4--that their geometric cross-section results in the 
effectively required total jet cross-section of the propelling nozzle 2 
corresponding to the required jet constriction. 
In other words, the mentioned respective geometrical cross-section must be 
set to be larger by the jet constriction factor. The effect of deflecting 
losses is also added to the influence of the jet constriction. 
FIGS. 10, 11 and 12 successively represent a central or resulting jet 
deflecting angle of 10.degree. (FIG. 10), 20.degree. (FIG. 11), and 
25.degree. (FIG. 12). As shown particularly in FIG. 12, the gas mass flow 
coming from a jet engine 3--viewed with respect to the right half of the 
propelling nozzle in the flight direction--coming from the transition duct 
or the transition duct part 16--in the rectangular pipe-type inlet 18 and 
by way of the flaps 8, 9, 10, which follow, is hardly deflected or is 
deflected only to a relatively small extent. The deflecting and therefore 
pressure losses which therefore occur hardly occur in this nozzle area or 
occur only to an extremely low extent, require slightly smaller, 
appropriately adapted cross-sectional surfaces Q1, Q2 in the flow ducts 
between the flaps 8, 9 and 9, 10. On the left nozzle half (in an 
assignment to the inlet 19) the deflecting losses increase, necessitating 
locally larger cross-sectional surfaces Q3, A4 between the flaps 10, 11 
and 11, 12 which can be adjusted according to the invention. 
In the mentioned context, FIGS. 10, 11 and 12 therefore illustrate clearly 
that, in each case, with respect to the central jet deflecting angle (Line 
L with flap 10), the jets according to Lines L1, L2 emerge from the right 
nozzle part at an exaggerated angle and from the left nozzle part 
according to Line L3, L4 at a down-played angle. By means of the 
appropriately adapted development and arrangement of the tracks 30', 30'' 
according to the invention and the corresponding development and 
arrangement of the control lever kinematics (FIG. 7 and 8), this can all 
be implemented in an advantageous manner. 
The invention therefore permits that the narrowest nozzle cross-sections 
developed between the flaps 8 to 12, in the manner of a convergent nozzle 
course, are always situated on the propelling nozzle outlet, while forming 
the Lines L1, L2, L3, L4 according to the respective jet deflecting 
directions. 
Therefore, in the case of the propelling nozzle according to the invention, 
in all operating positions, as a result of a reduction of the flow-through 
surface from the nozzle inlet in the direction of the nozzle outlet, there 
is always an acceleration of the flow. Therefore, no disadvantageous 
repercussions take place of the nozzle flow upon the engine or the 
corresponding engines 3, 4, despite an extremely fast response behavior of 
the propelling nozzle. 
The construction of the propelling nozzle according to FIGS. 1, 3, 4, 7, 8 
as well as FIGS. 9 to 12 or, in the sense of a comparable or similar 
"double-nozzle configuration" ensures, also in the case of a failure of 
one engine, such as 3, the full operatability; that is, the still 
exhausting gas mass flow of an engine, such as 4, can be accelerated by 
way of a nozzle half together with the inlet 19 in the manner of an 
individual nozzle, in which case then the central or resulting exit angle 
would be made available by the "new" central flap which is now responsible 
for it and the position of which would continue to be controlled by way of 
the previously central or medium flap 10 by the driving and control 
system. 
The basic idea of the invention could also be implemented if the flaps, in 
the case of a cascade-type multiflap arrangement were arranged at 
non-uniform mutual distances in the corresponding plane 13. 
According to the invention--and not shown in detail--, the lever-type 
control members shown, for example in FIG. 7, with respect to the 
above-mentioned "exaggerated or down-played angles" can be constructed to 
be adjustable with respect to their overall length in order to be able to 
be on the safe side according to the operational requirements. A 
controllable or adjustable lever length may also make sense with respect 
to the nozzle trimming in an adaptation to variable engines with a 
variable performance propulsion level. In view, for example, of the latter 
facts, the use of variable flap length may also be advantageous, or the 
use of flaps which are slightly or differently curved in the longitudinal 
direction, according to the always existing nozzle convergence. 
For example, by way of the accordion-type control lever linkage according 
to FIG. 7 (both sides outside rear), all nozzle flaps according to the 
invention are pivotally disposed on both ends, whereby a favorable 
distribution and introduction of force is obtained for the propulsion 
system. The lever-type control members therefore provide an additional 
"internal" equilibrium of forces in favor of reduced propulsion forces. 
Control devices, which are to be manufactured to be relatively light, in 
this case, particularly lever-type control members, represent other 
advantageous measures in favor of reduced propulsion forces, and thus, in 
turn, in favor of the fastest possible and as accurate as possible flap 
adjustments. As a result of their bearing, the flaps are loaded in the 
manner of plates so that, according to the invention, they can be 
constructed to be relatively slender as well as relatively light, for 
example, as hollow boxes with a honeycomb filling. 
In addition to the above-illustrated and explained propelling nozzle 
concepts as "single or basic concepts" according to FIGS. 5 and 6 with two 
respective flaps, a propelling nozzle configuration would be conceivable 
according to the invention which is not further explained in the drawings 
and which consists of two outer flaps and a central or medium flap. 
The invention also permits the providing of a propelling nozzle which is 
suitable for the processing and controlling of the gas mass flows of 
several jet engines. For this purpose, FIG. 13 illustrates, for example, a 
propelling nozzle 2' in an assignment to three jet engines arranged at 
uniform distance in parallel next to one another in an analogous 
construction according to Numbers 3 and 4 (FIG. 3). In this case a part of 
the nozzle housing is composed of three pipe-type inlets which communicate 
with the respective gas mass flows, specifically two outer 18', 19' inlets 
and one central inlet 48 which is integrated in it symmetrically to the 
nozzle. The inlets 18', 19', 48 have a rectangular cross-section, with 
transition pipe parts 16', 17' (outside) and 49 (inside) connected in 
front of the inlets or to the inlets, which--in the direction of the flow 
--change from an initially circular to a rectangular cross-section. Pipe 
bends 14', 15' which, on the exhaust-gas-flowside, communicate with the 
two outer engines, on the outlet side, are connected to the transition 
pipe parts 16', 17' which taper out on account of the outer inlets 18', 
19'. The central transition pipe part 49 communicates with a 
circular-cylindrical straight-axis pipe section 50 which, on the 
gas-exit-side, is connected to the central jet engine. In other words, in 
this case, the nozzle axis 20' or its extension in a symmetrically 
straight-axis extension by way of the pipe parts 49, 50, coincides with 
the axis of the central engine. Side-wall-side meeting points of the part 
of the nozzle housing containing the inlets 18', 19', 48 have the 
reference symbols S3', S3''. The housing section 21', which connects to 
the part of the nozzle housing containing the inlets 18', 19', 48, 
contains the flaps 8', 9', 10', 11', 12' which are pivotally arranged in 
the plane 13' at uniform mutual distances, with the additional 
introduction of two other flaps 51, 52. The medium or central flap 10' 
again represents the respective central or resulting thrust jet deflecting 
angle, for example, zero, in the straight-ahead flight position indicated 
here. Also in FIG. 13, the flaps, on the side of the swivel bearing, are 
to be connected behind the respective, front-connected side walls, flow 
guiding walls and meeting points from inlets I8', 19', 48 in an 
aerodynamically advantageous manner or, with as few losses as possible, 
communicating flat with the surface. The drive and control kinematics 
(lever-type control members, tracks, control cylinders, or the like) may 
be provided, for example, in the manner shown and described according to 
FIGS. 7 and 8. As a result, identical, comparable or similar elements and 
components, such as the propelling nozzle according to FIG. 13 itself are 
marked 2' and the following numbers . . . . 
In addition, the propelling nozzle concept according to the invention may 
be suitable and constructed for the three-dimensional thrust vector 
control, in that an additional deflecting wall or deflecting screen (FIG. 
1 and 2) could be pivoted into the total mass flow from the nozzle which 
can be deflected in a plane by means of the flaps, or could be pivoted 
away upward with respect of the gas mass flow, in which case the 
last-mentioned measure would mean a jet deflection in the manner of the 
so-called "Coanda effect". 
As shown in FIGS. 5 to 6, the flaps 8, 12 are constructed to be rounded on 
their rearward ends, specifically for an at least slight after expansion 
of the carried-through gas mass flow. However, for this purpose, both 
nozzle flaps 8, 12 may also receive an end-side inner widening in the 
sense of a slight nozzle divergence. In the case of several flaps (such 
as, FIG. 7), the individual flaps, for this purpose, at the downstream 
end, may be constructed to be tapering on both sides approximately in the 
form of a parabola or in a wedge shape. 
Although the invention has been described and illustrated in detail, it is 
to be clearly understood that the same is by way of illustration and 
example, and is not to be taken by way of limitation. The spirit and scope 
of the present invention are to be limited only by the terms of the 
appended claims.