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Патент USA US3024609

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March 13, 1962
J. M. s. KEEN
3,024,599
VARIABLE AREA JET PROPULSION NOZZLES
Filed June 10. 1959
2 Sheets-Sheet 1
March 13, 1962
J. M. s. KEEN
3,024,599
VARIABLE'AREA JET PROPULSION NOZZLES
Filed June 10. 1959
2 Sheets-Sheet 2
United States Pate
3,024,599
it
Patented Mar. 13, I962
1
3,024,599
VARIABLE AREA JET PROPULSION N OZZLES
John Michael Storer Keen, Allestree, England, assignor
to Rolls-Royce Limited, Derby, England, a British
company
Filed June 10, 1959, Ser. No. 819,456
Claims priority, application Great Britain July 14, 1958
7 Claims. (Cl. 60-35.6)
2
the secondary flap member being open to atmosphere.
In such an arrangement using a ram as above set forth,
the ram piston may have an area open to the interior of
the box structure. One advantage of this arrangement
is that in the event of failure of the power supply to the
ram when the ?ap members are in the second position,
the gas pressure within the box structure will act on the
piston to hold the ?ap members in position.
One embodiment of jet propulsion nozzle of' this in
This invention comprises improvements in or modi?ca
vention will now be described with reference to ‘the ac
tions of jet nozzles of the variable area kind as described 10 companying drawings in which:
and claimed in patent speci?cation Number 646,498.
FIGURE 1 is a view on the outlet end of the nozzle,
According to patent speci?cation Number 646,498 a
FEGURE 2 is an external side view of the nozzle,
jet nozzle for jet propulsion purposes comprises a tubular
FiGURE 3 is a section on the line 3—3 of FIGURE 1
wall member de?ning ‘a gas passage and having an outlet
drawn to a larger scale, and
at one end, and at least one ?ap member which is ad
FIGURE 4 is a section on the line 4-4 of FIGURE 3.
justable between a ?rst position in ‘which it projects into
The nozzle comprises a tubular wall 10 (FIGURES l
the gas passage upstream of the nozzle outlet to de?ne
and 2) which is frusto-conical with its larger end down
a ?rst eliective area of the nozzle less than the area of
stream, and a series of angularly~spaced hollow axially
said outlet of the tubular wall member, and ‘a second
extending streamlined structures 11, say six structures,
position in which it is retracted and the nozzle has a 20 which divide the peripheral portion of the gas passage
second effective area greater than the ?rst effective ‘area,
through the nozzle into a corresponding series of chan
and the total peripheral extent of such ?ap members be
nels 12 so as to reduce the noise-level as compared with
ing a minor proportion of ‘the total peripheral extent of
an equivalent plain convergent nozzle. The structures
the nozzle outlet.
25 11 are of such shape that the cross-section of the gas pas
According to the present invention in one aspect, in
sage decreases in the direction of gas ?ow.
a jet propulsion nozzle as claimed in patent speci?cation
In order to reduce the outlet area of the nozzle during
No. 646,498 the tubular wall has secured to it a series
say take-off of an aircraft a pair of ?ap arrangements 13
of angularly-spaced axially-extending structures which ov
are provided in a diametrically opposite pair of the
er at least the peripheral portion of the gas passage de
channels 12, which ?ap arrangements are retractable to
?ne a number of gas-?ow channels such that in operation
give a larger outlet area for cruise operation.
a silencing effect is obtained as compared with an equiva
Each flap ‘arrangement 13 comprises (FIGURE 3) a
lent plain nozzle, and the or each ?ap member extends
main ?ap 14 which is pivoted at its upstream end to the
circumferentially between a pair of said structures and
tubular wall member 10 and which extends from its pivot
in said ?rst position the lateral edges of the flap member
15 downstream towards the outlet of the nozzle. The
co-operate with adjacent circurnferent-ially-facing walls
main ?ap 14 has ‘a ?rst position of adjustment shown in
of the pair of structures to reduce the outlet area of the
dotted lines in FIGURE 3 in which it projects into the
channel between them.
channel 12 between the adjacent structures 11 and co-op
According ‘to the invention in another ‘aspect, in a jet
erates by its lateral edges 14a with the walls of the struc
propulsion nozzle as claimed in patent speci?cation No.
tures 11 to reduce the cross-section of the channel 12
646,498 the (or each) ?ap member is pivoted by its up
stream end to the tubular wall member, and has pivoted
to its downtsream end one end of a secondary flap mem
ber the other end of which is connected to power means
(see FIGURE 1). The main ?ap 14 has a second posi
tion of adjustment shown in full lines in FIGURE 3 in
which it occupies a cut-out 16 in the tubular wall member
10 and does not obstruct the channel 12. It will be
seen that there is a substantial gap between the upstream
by which movement of the ?ap members is effected, the
secondary ?ap member forming in said ?rst position a 45 edge of the flap 14 and the upstream edge of the cut-out
downstream-facing wall extending outwardly from said
downstream end.
Preferably, the secondary ?ap has mounted on it at said
other end roller means running in tracks which may be
curved and are provided on ?xed structure, the rollers
and tracks being adapted to reduce the loads being trans
mitted from the ?ap to the power means. The power
means is conveniently ‘an axially-extending ram, whereof
16.
Each ?ap arrangement also comprises a secondary flap
17 Which is connected at one of its ends through pivot 18
to the downstream end of the main ?ap 14. The other
end of the ?ap 17 has mounted on it a pin 19 carrying
a pair of rollers 20 (FIGURES 3 and 4) and these rollers
co-operate with axially-curved channelled tracks 21
formed on the internal surface of a member 22 secured
to the top of a box structure. Since the rollers 26; run in
the operating piston is connected to the said other end of
the secondary ?ap member by a link, and means is pro 55 channels 21 any side load tending to cause lateral dis
vided to limit radially-inward movement of the ?ap mern~
bers when the gas pressure in the nozzle is low or at
placement of the ?aps 17 will cause the rollers 29 to bear
Preferably, it is ‘arranged that when the ?ap members
against the sides of the channels and in this way the ?ap
is supported against movement under the action of side
loads.
are in the ?rst position, the secondary flap member is
loaded on its upstream-facing surface by pressure gas de
the flap 17 and a link 24 by which the ?ap 17 is connected
zero.
The pin 19 also provides a pivotal connection between
rived from the passage and on its downstream~facing sur
to a ram piston 25 which works in a ram cylinder 26
which is secured at one end to a ?ange 27 on the tubular
gas loads on the secondary flap member assist to main
wall member 16' and at its other end to the box structure
tain it in position. This may be achieved by providing a 65 23. The cylinder 26 has pressure ?uid supply connec
cut-out in the tubular wall member to receive the ?rst~
tions 28, 29 to it and a smaller diameter portion 26a open
face by substantially atmospheric pressure, whereby the
to the interior of the box structure 23. The piston 25
mentioned ?ap member when it is retracted and by pro
viding a box structure externally of the tubular member
has an extension 25a which is slidable in a bush 26d lo
cated in the cylinder portion 26a and the extension 25a is
to cover the cut-out and flap members, the box structure
70
hollow so as to permit angular movement of the link 24.
upstream of the secondary ?ap member when in the ?rst
The extension 25a also allows an area of the downstream
position being open to the gas passage and downstream of
8,024,599
3
4
face of the piston to be subjected to the pressure within
the box structure 23. A sealing ring 2512 is provided be
tween the upstream end of cylinder portion 26a and the
extension 25a of piston 25.
ary flap member and running in said channelled tracks,
the rollers and tracks being adapted to prevent tangential
loads being transmitted from the ?ap to the power
means.
The link 24 is formed with a hooked lug 3G (FIGURES
3 and 4) projecting into a stepped channel 31 which runs
wherein the tracks are curved.
parallel with tracks 21, the lug 30 and channel 31 serving
to prevent radially inward movement of the flap arrange
said power means comprising an axially-extending ram
3. A jet propulsion nozzle according to claim 2,
4. A jet propulsion nozzle according to claim 2,
ments 13 when the gas pressure within the tubular wall 10
is low or at zero.
having an operating piston, a link connecting said piston
10 to the said other end of the secondary ?ap member, and
The box structure 23 has a slot 32 in its downstream
wall through which the interior of the box structure on the
downstream side of the secondary ?ap 17 is in communi
cation with atmosphere.
When the main ?ap 14 is moved into its ?rst position
(dotted lines in FIGURE 3) by feeding pressure ?uid
such as compressed air to cylinder space 2612, the second
ary ?ap 17 extends radially outwards as shown in dotted
means limiting radially-inward movement of the ?ap
members when the gas pressure in the nozzle is low or
at zero.
5. A jet propulsion nozzle according to claim 4,
wherein the means to limit said radially-inward move
ment of the ?ap members comprises a hooked lug on the
link and a stepped channel which runs parallel with
the tracks, said hooked lug engaging in the stepped
lines in FIGURE 3 to form a downstream facing wall.
channel.
Since gas can flow as indicated by arrow 33 from the gas 20
6. A jet propulsion nozzle comprising a tubular wall
passage of the nozzle into the box structure 23 on the
member de?ning a gas passage and having an outlet at
upstream side of the flap 17 and the downstream side
one end, and at least one ?ap arrangement which is ad
of the flap 17 is at substantially atmospheric pressure,
justable between a ?rst position in which it projects into
the flap 17 has a resultant load on it tending to main
the gas passage upstream of the nozzle outlet to de?ne a
tain it in position. In this position, the outlet area of 25 ?rst effective area of the nozzle less than the area of said
the nozzle is a minimum.
outlet of the tubular wall member, and a second position
To move the flaps 14, 17 to their second and re
in which it is retracted and the nozzle has a second effec
tracted positions (full lines in FIGURE 3), pressure ?uid
tive area greater than the ?rst effective area, power means
is fed to cylinder space 260 and the piston 25 moves to
for effecting adjustment of the ?ap arrangement, the
the left. In this position of the ?aps, ?ap 14 forms
a smooth continuation of the tubular wall member 10
and ?ap 17 is housed in the box structure 23. If the
pressure ?uid supply to ram 25, 26 should fail, the gas
load acting to the left on piston 25 due to the gas pres
sure Within the box structure 23 on the upstream side
of the ?ap 17 holds the parts in their full line positions.
I claim:
1. A jet propulsion nozzle comprising a tubular wall
member de?ning a gas passage and having an outlet at
one end, and at least one ?ap arrangement which is
adjustable between a ?rst position in which it projects
into the gas passage upstream of the nozzle outlet to
de?ne a ?rst effective area of the nozzle less than the
area of said outlet of the tubular wall member, and a
second position in which it is retracted and the nozzle
has a second effective area greater than the ?rst effective
area, power means for effecting adjustment of the ?ap
arrangement, the ?ap arrangement comprising a main
?ap arrangement comprising a main ?ap member extend
ing longitudinally of the tubular wall member and piv
oted by its upstream end to the tubular wall member,
and a secondary ?ap member pivoted by one end to the
downstream end of the main ?ap member and pivotally
connected by its other end to the power means, the sec
ondary ?ap member forming in said ?rst position a down
stream-facing wall extending radially outwardly from said
downstream end of the main ?ap member, there being
a cut-out in the tubular wall member to receive the main
?ap member when the ?ap arrangement is retracted, and
a box structure externally of the tubular member to
cover the cut-out and ?ap arrangement, the secondary ?ap
member when in said ?rst position projecting radially
into the box structure and dividing the interior of the
box structure into upstream and downstream spaces, the
space of the box structure upstream of the secondary ?ap
member being open to the gas passage and the space of
the box structure downstream of the secondary ?ap mem~
?ap member extending longitudinally of the tubular
ber being open to atmosphere.
wall member and pivoted by its upstream end to the 50
7. A jet propulsion nozzle according to claim 6, said
tubular wall member, and a secondary flap member
power means comprising an axially extending ram having
pivoted by one end to the downstream end of the main
an operating piston, the ram piston having an area open
?ap member and pivotally connected by its other end to
to the upstream space of the box structure so that in the
the power means, the secondary ?ap member forming
in said ?rst position a downstream-facing wall extend
ing radially outwardly from said downstream end of the
main ?ap member, the secondary ?ap member having
?rst and second surfaces which in the ?rst position of
the ?ap arrangement face upstream and downstream re
spectively, means permitting the secondary ?ap member
to be loaded on its upstream-facing surface by pressure
gas derived from the gas passage and on its downstream
event of failure of the power supply to the ram when the
flap members are in the retracted position, the gas pres
sure Within the box structure acts on the piston to hold
the flap arrangement in said retracted position.
References Cited in the ?le of this patent
UNITED STATES PATENTS
2,794,317
2,928,234
Brown _______________ __ June 4, 1957
Brown _____________ __ Mar. 15, 1960
165,369
Australia ____________ __ Sept. 26, 1955
member, channelled tracks provided on ?xed structure,
558,987
1,141,221
roller means mounted on said other end of the second
1,164,936
Belgium _____________ __ Nov. 1, 1957
France ____________ __ Mar. 11, 1957
France ______________ __ May 19, 1958
facing surface by substantially atmospheric pressure,
whereby the gas loads on the secondary ?ap member
assist to maintain it in said ?rst position.
65
2. A jet propulsion nozzle according to claim 1,
comprising ?xed structure externally of the tubular wall
FOREIGN PATENTS
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