Pivoting door type thrust reverser with deployable members for efflux control and flow separation

A novel pivoting door thrust reverser which provides a nozzle for the exhaust of a bypass engine that ensures a smooth continuous flow path for the exhaust without leakage around the pivoted upper and lower reverser doors. The upper reverser door is provided with a pair of biased cooperating crescent shaped kicker members that are biased outwardly in a controlled movement when the doors are deployed to deflect the upper portion of the reversed exhaust efflux forwardly in a predetermined direction to avoid interference with the control surfaces of the aircraft. The lower reverser door is provided with pivoted splitter plates that are biased outwardly when the door is deployed to abut and form a unitary splitter element that divides the lower exhaust efflux into two portions that are directed forwardly and away from the inlet of the engine to preclude foreign object damage to the engine. The thrust reverser is lightweight, uses simple, inexpensive mechanisms, and operates in a very efficient manner when deployed as a thrust reverser and when stowed as an exhaust nozzle for the engine.

BACKGROUND OF THE INVENTION 
1. Field of the Invention 
This invention relates generally to the field of pivoting door thrust 
reversers and more particularly, but not by way of limitation, to an 
improved thrust reverser which provides improved mechanisms for directing 
the exhaust efflux to preclude foreign object damage to the engine and 
interference with the control surfaces of the aircraft and that provides 
an exhaust nozzle having improved performance in flight. 
2. Description of the Prior Art 
In order to reduce the landing distance of a jet engine powered aircraft, 
as well as to increase the margin of safety when the aircraft is landing 
on a wet or icy runway, thrust reversers are utilized on the jet engines 
in order to provide a braking thrust for the aircraft. Such thrust 
reversers function to reverse the direction of the jet thrust, from a 
normally rearward direction used for propelling the aircraft in flight, to 
a generally forward direction for slowing or braking the aircraft. 
For low bypass jet engines, the thrust reversers are typical formed by 
pivoting thrust reverser doors which are pivotally mounded on a fixed 
structure attached to the engine and to another component of the nacelle. 
These reverser doors and fixed structure cooperate to form the final 
nozzle of the gas turbine engine propulsion system. The doors are capable 
of pivoting between two positions about two spaced parallel axes which are 
transverse and substantially diametrical with respect to the exhaust of 
the engine. 
The first position finds the doors in a stowed position, out of the direct 
path of the exhaust forward thrust of the engine. In this position, the 
doors form, in cooperation with the fixed structure, the exhaust nozzle of 
the gas turbine engine so that the thrust of the engine is directly 
rearward, thereby producing forward thrust for the aircraft. In a second 
position, the doors are pivoted about their pivot axes until their 
trailing edges abut in a transverse thrust deflecting or deployed 
position, to block and redirect the engine thrust generally forward and 
thereby produce the braking thrust for-the engine when needed. 
The thrust reversers are generally mounted on a fixed structure. This fixed 
structure basically serves a dual role. In the forward thrust mode of 
operation of the jet engine, i.e. when the reverser doors are in the 
stowed position, the fixed structure forms a part of the envelope of the 
jet flow and is intended to ensure the best possible flow continuity with 
the inner skin of the thrust reverser doors. 
In the reverse thrust operation, i.e. when the reverser doors are deployed, 
the fixed structure provides the throat of the nozzle, and defines as well 
the spacing distance from the thrust reverser doors. 
Both of these functions of the fixed structure are important criteria for 
the proper operation of the jet engine. While in the forward thrust mode, 
a good flow continuity is essential to the proper forward thrust 
performance. In addition, the jet exhaust pipe must adequately define the 
throat area in reverse thrust and the spacing distance in order to satisfy 
the operational compatibility requirements of the engine and of the thrust 
reverser when the thrust reverser doors are deployed. 
Experience has shown that often thrust reversers tend to favor performance 
more in the reversing function of operation. But this, unfortunately, is 
at the expense of the performance provided in the forward thrust mode of 
operation, meaning that performance degradation during forward thrust is 
generally associated with the installation of thrust reversers. This is 
unfortunate since thrust reversers are in operation generally for only 15 
to 30 seconds of a flight. 
Further, thrust reversers of the prior art have not dealt well with the 
requirements of deflecting one portion of the reversed exhaust flow 
upwardly so that it will not adversely effect control surfaces of the 
aircraft and deflecting a second or other portions of the reversed exhaust 
flow downwardly and forwardly in a manner that will not cause foreign 
objects lying on the surface of the landing field to be blown forward so 
that such objects may be ingested by the engine and thereby cause injury 
to such engine. Attempts to provide simple inexpensive mechanisms to 
control the exhaust efflux in the desired manner have not been entirely 
successful. 
Typical pivoting reverser doors generally require a pit or concave portion 
near their leading edges. This type of configuration does not provide a 
smooth internal exhaust flow through the nozzle contributing to the 
degradation in performance during operation in the forward thrust mode. 
Such doors often have an efflux deflecting member positioned near the 
leading edge, with such member being pivoted downwardly to deflect the 
exhaust flow as the door is deployed. Also, problems have been encountered 
with past thrust reverser door designs in attempting to seal the doors 
adequately in the stowed position and preclude the exhaust pressure in 
flight leaking out past the stowed doors to cause drag and marginal 
performance as well as raising the possibility of having the doors deploy 
in flight. 
Thus, a need exists for a pivoting door thrust reverser that provides a 
simple, inexpensive, and highly reliable mechanism for the desired forward 
deflection of the exhaust flow in the deployed mode and to direct portions 
of the reversed flow so as to avoid interference with control surfaces of 
the aircraft and to preclude the downwardly directed reversed flow from 
blowing foreign objects forwardly to a position for ingestion by the 
engine. A need also exists for a thrust reverser that meets the above 
criteria while precluding leakage from the reverser unit while in flight 
and also provides a nozzle that provides a relatively smooth continuous 
flow for the exhaust of the engine. It is believed that such requirements 
are met by the instant invention which provides a practical state of the 
art thrust reverser in an economical manner. 
SUMMARY OF THE INVENTION 
Briefly stated, the present invention provides a pivoting door thrust 
reverser for use with a bypass aircraft engine that includes a fixed 
structure arranged to be secured to the aft end of the engine and adapted 
to provide a nozzle for the exhaust of the engine. First and second 
generally symmetrical thrust reverser doors are pivotally attached at the 
aft end of the fixed structure and are adapted to be movable between a 
stowed non-reversing position and a deployed thrust reversing position. 
Each of the reverser doors is provided with a pair of biased members that 
are biased outwardly to a desired position as the doors are pivoted to a 
deployed position thus deflecting the reversed flow of the engine in a 
predetermined manner so as to preclude foreign object damage to the engine 
from ingestion of objects from a landing field surface being blown forward 
and to preclude interference of the reversed air flow with the control 
surfaces of the aircraft. The kicker members of the first reverser door 
preferably are generally crescent shaped and are biased outwardly by 
torsion spring means to a desired position when the door is deployed. Such 
kicker members and longitudinally extending fences provided along the 
lower edges of the door direct the portion of the reversed exhaust flow 
forwardly in a desired manner to preclude interference with the aircraft 
control surfaces. 
The second or lower reverser door is provided with two spring biased 
pivoted generally rectangularly shaped flow separator members that are 
biased outwardly when the door is deployed to rotate inwardly into 
abutment with each other to provide a unitary flow splitter that divides 
that portion of the exhaust flow that is reversed by the second door into 
two portions which are directed forwardly to each side and away from the 
inlet of the engine to each side to preclude foreign objects being 
ingested by the engine. Suitable longitudinally extending fences are 
provided on the longitudinal edges of the second door and cooperate with 
the door and kicker members in deflecting the exhaust in the desired 
direction. 
Bumper members are secured to the fixed structure and cooperate with the 
rotatable members of each door to urge such members to a secured home 
position when the doors are pivoted and returned to a stowed position. 
The fixed structure and the reverser doors cooperate to provide an exhaust 
nozzle that has a smooth interior surface that is generally continuous to 
minimize drag of the thrust reverser when in flight. An inner and outer 
set of resilient seals are provided on the fixed structure for cooperation 
with portions of the reverser doors to preclude leakage of the exhaust in 
flight and to further enhance performance of the reverser. 
Other features and attendant advantages of the present invention will 
become apparent to those skilled in the art from a reading of the 
following detailed description in conjunction with the accompanying 
drawings which illustrate the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
Referring now to the drawings in detail and in particular to FIG. 1, the 
reference character 10 generally designates a pivoting door thrust 
reverser constructed in accordance with a preferred embodiment of the 
invention. The pivoting door thrust reverser 10 includes a fixed structure 
12 and a pivoted first or upper reverser door member 14 and a pivoted 
second or lower reverser door member 16. The doors 14 and 16 are arcuate 
and are generally symmetrical in shape. The fixed structure 12, as-seen in 
FIG. 3, is adapted to be secured to the aft end of a bypass engine 18 
which issues a hot gas stream therefrom and to a suitable nacelle 
component 20 which cooperates with the engine 18 to provide a bypass duct 
22 for the flow of bypass air generated by the engine. 
As shown most clearly in FIG. 3, the fixed structure 12 and the upper and 
lower reverser doors 14 and 16 cooperate to provide a substantially smooth 
nozzle 24, shown in dotted line outline, that is a continuation of the 
exhaust outlet of the engine 18 and the bypass duct 22. 
Referring again to FIG. 1, the fixed structure 12 includes an annular 
portion 26 that is adapted to be secured to the engine 18 and to a nacelle 
component 20 in a suitable manner. The annular portion 26 is of 
conventional construction for aircraft components and may include a 
suitable sound attenuation treatment 28 for the inner liner. The 
particular acoustic treatment 28 shown for the inner liner is a 
conventional perforated honeycomb core with an imperforate back sheet. The 
fixed structure 12 includes two opposed longitudinally extending side 
portions 30 and 32. The side portions 30 and 32 house the pivot points for 
the doors 14 and 16 as well as the actuator mechanisms (not shown) which 
pivot the doors 14 and 16 from a stowed positions as seen in FIG. 3 to the 
deployed position shown in FIG. 1 and back to the stowed position. The 
trailing ends of the side portions 30 and 32 are secured to an annular 
portion 34. As is apparent in FIGS. 1 and 3, the annular portion 26, the 
side portions 30 and 32, and the annular rear portion 34 of the fixed 
structure 12 and the upper and lower doors 14 and 16 cooperate to provide 
a smooth continuous nozzle for the engine 18 and bypass duct 22 to provide 
maximum thrust in flight without incurring unwanted drag from the thrust 
reverser design. 
When the doors 14 and 16 are deployed upon landing to slow the aircraft, 
the trailing edges of the doors abut, as seen in FIG. 1, to deflect the 
exhaust efflux forwardly in an upwardly directed portion and a downwardly 
directed portion. A pair of normally stowed kicker plates 36 and 38 
carried by the door 14 are biased outwardly at a controlled rate of 
movement for a predetermined distance to further deflect the first portion 
of exhaust in a more forwardly direction. Longitudinally extending side 
fences 40 and 42 are preferably secured to the lower longitudinal edges of 
the door 14 to aid in controlling the upper plume of the exhaust in a 
controlled manner and away from control surfaces of an associated aircraft 
to enhance control of the aircraft upon landing and, if the landing is 
aborted, upon takeoff. 
The lower door 16 is provided with two flow separator plates 44 and 46 that 
are normally urged to a secured position within the door 16 and which are 
biased outwardly to a flow splitting position upon deployment of the door 
16 to split the downwardly extending exhaust plume into two portions that 
extend outwardly and forwardly from the reverser 10 to preclude foreign 
objects lying on a landing field surface from being blown upwardly for 
ingestion by the engine with resultant damage. Suitable longitudinally 
extending side fences 48 are secured to the upper longitudinally extending 
edges of the lower door 16 to assist in controlling and directing the 
split plumes as desired. The efflux pattern achieved by the thrust 
reverser 10 is seen most clearly in FIG. 2 and illustrates the 
effectiveness of such reverser in providing the desired efflux pattern. 
Referring now to FIG. 4 which represents a cross-sectional view taken along 
lines 4--4 of FIG. 3, further details of the doors 14 and 16 will be 
explained. Each of the kicker members 36 and 38 is generally crescent 
shaped and is pivoted at its outer end to the door 14 by a suitable pivot 
assembly 50 which includes a suitable torsion spring 52 that biases the 
associated kicker member outwardly. When the door 14 is stowed as seen in 
FIGS. 4, 5 and 6, the outwardly biased kicker members 36 and 38 are urged 
inwardly into a secured position within the outline of the door by contact 
with a suitable stow bumper 54 positioned on the upper outer surface of an 
inner portion 56 of the annular portion 26 of the fixed structure 12. 
When the door 14 is rotated to a deployed position, as seen in FIGS. 7 and 
8, each torsion spring 52 biases each associated kicker member 36, 38 
outwardly to a predetermined position. This position and the rate of 
outward movement of the kicker members 36 and 38 are determined in the 
following manner. The upper deflector door 14 is provided with a fitting 
58 that extends inwardly from the door's outer surface and which is 
attached to suitable structure 60 within the door 14 to support it. 
In the illustrated preferred embodiment of the invention, the kicker 
members 36 and 38 interact in cooperating to control the rate at which 
they rotate outwardly from the door 14 and the extent to which they extend 
outwardly to deflect further the reversed air flow. The rate of movement 
is controlled to preclude the kicker members or deflector edges from 
coming into full contact with the reversed air stream too quickly. 
As seen in FIGS. 7, 8 and 8A, kicker member 36 can be considered to be a 
tongue member which cooperates with kicker member 38 acting as a clevis 
member. As the door 14, is opened, the kicker members 36 and 38 cooperate 
to rotate outwardly to a desired predetermined position. This cooperation 
is afforded by the fitting 58 being provided with a sloping arcuate guide 
track 62 having a lower fixed portion 63. The clevis shaped end of kicker 
member 38 is provided with a suitable spacer element 64 and a cam follower 
member 65 having a hook shaped upper portion 66. The spacer element 64 and 
the cam follower hook member are secured to the clevis portion of the 
kicker member 38 in a suitable manner as by bolts 67. 
As seen in FIGS. 7, 8 and 8A, the spacer element 64 extends through a 
particularly shaped opening 68 provided in the kicker member 36. As the 
door 12 is opened, the torsion springs 50 rotate the associated kicker 
members 36 and 38 outwardly. As the door 38 rotates outwardly the rate of 
such rotation is controlled by the sliding movement of the cam follower 
element 65 within cam track 62 until the hook portion 66 of the guide 
element 65 contracts the stop element 63 of the guide track 62 to limit 
the outward movement of the kicker member 38 from the door 12. 
As the kicker member 38 rotates outwardly, the associated kicker member 36 
also rotates outwardly. The tongue portion of the kicker member 36 which 
is received within the clevis portion of the kicker member 38 is 
controlled in movement by the spacer element 64 carried by the kicker 
member 38 contracting the inner edge of said particularly configured 
opening 68 provided in the kicker member 36 in a sliding movement and 
constraining its movement to a desired cooperative movement. 
When the door 12 is rotated inwardly to a stowed position, the outer edges 
of the doors 36 and 38 contact the bumper 54 and the kicker members 36 and 
38 contact the bumper 54 and the kicker members 36 and 38 are guided back 
to their original stowed positions. 
It will be appreciated that while a particular arrangement has been 
illustrated in FIGS. 7, 8 and 8A for providing a cooperative deployment of 
the kicker members 36 and 38 it would be within the scope of the invention 
to provide other means that would yield the same result. For example, 
roller means could be carried by the door 38 that would cooperate with the 
guide track 62 and with the opening 70 in door 36. 
For ease of illustration, the door 14 and the kicker members 34 and 36 are 
shown partially deployed in FIGS. 7 and 8 but do illustrate how door 14 
deflects one portion of the exhaust flow upwardly and forwardly while the 
extended kicker members 36 and 38 cooperate to deflect further that 
portion of the exhaust efflux in a more forward direction. 
Referring now to FIGS. 4, 9, 10 and 11, the arrangement of the lower door 
16 and the splitter plates 44 and 46 will be explained in greater detail. 
As seen in FIG. 4, each of the generally rectangularly shaped splitter 
plates 44 and 46 are positioned within the general outline of the door 16 
when it is in its stowed position by means of a suitably shaped stow 
bumper 72, positioned on the lower outer surface of the portion 56 of the 
fixed structure 12, that urges such plates 44 and 46 to a secured 
position. Each of the plates 44 and 46 are pivotally secured at their 
lower ends to the door 16 by a suitable torsion spring assembly 74, shown 
in FIG. 11, that biases the splitter plates 44 and 46 outwardly as the 
door 16 is deployed and into abutting contact, as seen in FIG. 9, to form 
what may be considered to be one unitary splitter element to split the 
lower portion of the exhaust efflux into two desired portions. 
As the door 16 is returned to a stowed position, the rounded portions on 
the outer inside corner 75 of each flow separator plate 44 and 46 engage 
the forward portion of the stow bumper 72 and are spread apart to the 
secured position shown in FIG. 4 as the door 16 rotates inwardly to the 
stowed position. The flow separator plates 44 and 46 extend sufficiently 
into the lower efflux of the exhaust flow to spit such flow rather than 
acting like the upper kicker members 36 and 38 which more forwardly direct 
the upper efflux. 
Referring now to FIG. 12, it will be seen that the upper door 14 is 
journaled to the fixed structure 12 by pivots 76 that lie on an axis 
transverse to the fixed structure 12. Similarly, the lower door 16 is 
journaled on the fixed structure 12 by suitable pivots 78 that lie on an 
axis transverse to the central axis of the fixed structure 12. To ensure 
that the upper and lower doors 14 and 16 do not leak exhaust flow during 
flight and thereby reduce the performance of the nozzle provided by the 
thrust reverser 10, the fixed structure 12 is provided with a first bulb 
seal 80 and a second lip seal 82 that cooperate with the first and second 
doors 14 and 16 to preclude leakage. 
FIG. 13, taken along lines 13--13 of FIG. 12, shows the outer bulb seal 80 
cooperating with the thrust reverser door 14. FIG. 14 shows the inner lip 
seal 82 and the bumper 54 carried by the fixed structure 56 cooperating 
with the door 14 for sealing. FIG. 15 should be viewed from an orientation 
in which the arrows 86 indicate up and show the outer bulb seal 80 and the 
inner lip seal 82 cooperating with the upper door 14. FIG. 16 taken along 
lines 16--16 of FIG. 12 show the aft bulb seal 80 carried by the aft 
portion 34 of the fixed structure 12 cooperating with the upper door 14 
for sealing. FIG. 17 taken along lines 17--17 of FIG. 12 show the bulb 
seals 80 carried by the fixed structure portion 30 cooperating with the 
door 14 in its stowed and deployed positions. FIG. 18 shows the upper door 
14 cooperating with the aft bulb seal 80 carried by the side fixed 
structure portion 30 for sealing purposes. 
In summary, it has been seen how the present invention provides a novel 
pivoting door thrust reverser which is provided with upper and lower doors 
that have pivoted members that deflect the upper portion of the exhaust 
flow forwardly to avoid control surfaces of the aircraft and split the 
lower portion of the exhaust flow into two portions that avoid ingestion 
by the engine of foreign objects. The control of such efflux is provided 
by simple novel mechanisms carried by the upper and lower doors. The 
thrust reverser also provides a very efficient nozzle that provides a 
smooth continuous flow of exhaust in flight for maximum thrust and peak 
operating efficiency. A seal arrangement cooperates with the thrust 
reverser doors to preclude leakage of the exhaust during forward thrust. 
Changes maybe made in the combination and arrangement of parts or elements 
as heretofore set forth in the specification and shown in the drawings, it 
being understood that changes may be made in the precise embodiment 
disclosed without departing from the spirit and scope of the invention as 
defined in the following claims.