Appeal No. 2002-0538
Application 09/220,468
stator vanes. The engine also comprises a thrust modulator which
operates without the necessity of reducing engine speed. In
Uehling’s words,
[a]s shown schematically in FIG. 3, the turbojet
engine 10 is provided with a bypass pipe 24 having a
valve 26 interposed therein. One end of the bypass
pipe 24 is connected to the compressor 14 near its
discharge end, and the valve 26 is actuated by the
pilot to bleed off a certain percentage of compressor
discharge air thereby reducing the mass flow though the
combustion system 16 and the turbine 18. A portion of
this bleed air is provided to a turbine cooling flow
path 27 from which it is delivered to various
components of the turbine 18 to cool the same. . . .
. . . [T]he remaining portion of the bleed flow
within the pipe 24 is piped from compressor discharge
to the turbojet tail pipe 19 forward of the exhaust
nozzle 20 and downstream of the turbine 18 . . .
through thrust spoiling means, generally designed by
the numeral 28, as shown in FIG. 3.
As shown in both FIG. 3 and FIG. 4, the thrust
spoiling means 28 take the form of a plurality of swirl
inducing nozzles 30 positioned within a manifold 32, to
which the bleed pipe 24 is connected. By means of the
swirl inducing nozzles 30 the bleed flow is introduced
into the tail pipe 19 so as to maximize swirl of the
gas flowing within the tail pipe 19, thereby
significantly increasing the tail pipe pressure and
momentum losses and reducing the nozzle thrust
coefficient, which, in turn, causes an instantaneous
and additional increment of thrust reduction [column 3,
line 54, through column 4, line 14].
Figure 3 shows Uehling’s bypass pipe 24, which channels
cooling air from the compressor 14 to the turbine 18 via flow
path 27, as communicating with the compressor at a position
adjacent the tip clearance area of a row of rotating blades. As
4
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Last modified: November 3, 2007