A reaction control system nozzle block is provided for testing the response characteristics of space vehicles to a variety of reaction control thruster configurations. A pressurized air system is connected with the supply lines which lead to the individual jet nozzles. Each supply line terminates in a compact cylindrical plenum volume, axially perpendicular and adjacent to the throat of the jet nozzle. The volume of the cylindrical plenum is sized to provide uniform thrust characteristics from each jet nozzle irrespective of the angle of approach of the supply line to the plenum. Each supply line may be plugged or capped to stop the air supply to selected jet nozzles, thereby enabling a variety of nozzle configurations to be obtained from a single model nozzle block

Daileda, J. J.

Dresser, H. S.

English

NASA Technical Reports Server

United States Patent [191 
Fletcher et al. 
[I11 4,091,665 
[45] May 30, 1978 
[54] MULTI-PURPOSE WIND TUNNEL 
REACTION CONTROL MODEL BLOCK 
[76] Inventors: James C. Fletcher, Administrator of 
the National Aeronautics and Space 
administration, with respect to an 
invention of; Henry S. Dresser, La 
Mirada; Joseph J. Daiieda, Torrance, 
both of calif. 
[21] Appl. No.: 767,911 
[22] Filed: Feb. 11,1977 
[51] Int. Cl.2 .............................................. GOlM 9/00 
[52] U.S. CL. .................................. 73/14? 239/265.25 
[58] Field of Search ..................... 73/14? 239/265.11, 
239/265.25, 265.27 
[56l References Cited 
U.S. PATENT DOCUMENTS 
3,190,584 6/1965 Gire et al .......... 239/265.25 X 
3,752,401 8/1973 Kizilos ............ 239/265.11 X 
3,802,190 4/1974 Kaufmann ................... 239/265.27 X 
primav Examiner-Richard C. Queisser 
Assistant Examiner-Joseph W. Roskos 
Attorney, Agent, or Firm-Carl 0. McClenny; Marvin F. 
Matthews; John R. Manning 
A reaction control system nozzle block is provided for 
testing the response characteristics of space vehicles to 
a variety of reaction control thruster configurations. A 
pressurized air system is connected with the supply lines 
which lead to the individual jet nozzles. Each supply 
line terminates in a compact cylindrical plenum volume, 
axially perpendicular and adjacent the throat of the jet 
nozzle. The volume of the cylindrical plenum is sized to 
provide uniform thrust characteristics from each jet 
nozzle irrespective of the angle of approach of the sup- 
ply line to the plenum. Each supply line may be plugged 
or capped to stop the air supply to selected jet nozzles, 
thereby enabling a variety of nozzle configurations to 
be obtained from a single model nozzle block. 
[57l ABSTRACT 
8 Claims, 5 Drawing Figures 
24.25, 
https://ntrs.nasa.gov/search.jsp?R=19780023186 2020-03-20T13:26:16+00:00Z
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U. S. Patent May30, 1978 Sheet2 of2 4,09 1,665 
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MULTI-PURPOSE WIND TUNNEL REACTION 
CONTROL MODEL BLOCK 
ORIGIN OF THE INVENTION 
The invention described herein was made in the per- 
formance of work under a NASA contract and is sub- 
ject to the provisions of Section 305 of the National 
Aeronautics and Space Act of 1958, public law 85-568 
(72 Stat. 435; 45 U.S.C. 2457). 
BACKGROUND OF THE INVENTION 
This invention pertains to methods and apparatus for 
model testing in wind tunnels and, more particularly, to 
method and apparatus for use in wind tunnel testing of 
models which utilize reaction control systems. 
Reaction control systems are used to orient vehicles 
in flight under conditions in which aerodynamic control 
devices are ineffective. Such conditions Darticularly 
5 
10 
15 
occur during the flight of manned and unmanned vehi- 20 
cles in the upper regions of the atmosphere or in space. 
Reaction control jets are generally placed on both the 
right and left sides and in the nose and aft sections of the 
vehicle to provide pitch, yaw, and roll control. 
ing to ascertain the flight characteristics and response of 
The design of space vehicles requires extensive test- 25 
each particular vehicle design. An arrangementof reac- 
tion control jet thrusters is first defined and the response 
of the model to that particular configuration is experi- 
mentally determined. A variety of such configurations 
are designed and tested whereby the optimum perfor- 
mance characteristics relative to the model response to 
the reaction control system can be ascertained. 
It has been conventional to fabricate a series of indi- 
vidual reaction control system model nozzle blocks 
each containing a particular jet nozzle thruster arrange- 
ment for each test. A large plenum was provided for 
each jet thruster arrangement to ensure proper flow of 
the thrusting medium to the nozzles. The large plenum 
necessitated individual nozzle blocks since individual 
jets could not then be controlled and, further, the size of 
the nozzle block would become enlarged if alternate 
jets were incorporated. The thrust characteristics of 
each test configuration had to be calibrated and the 
individual thrusters on each nozzle block adjusted to 
provide predetermined thrust characteristics. 
Separate reaction control system nozzle blocks were, 
therefore, fabricated for each thruster configuration 
under consideration. Such individual fabrication and 
adjustment, as hereinabove discussed, is costly since the 
manufacture and calibration of the reaction control 
model test blocks requires a high degree of precision. 
Further, extensive model testing down-time is required 
to install and align each new model test nozzle block on 
the model. 
These disadvantages of the prior art are overcome by 
the present invention, and an improved method and 
apparatus are provided for reaction control system test- 
ing of space vehicles during simulated performance 
30 
35 
40 
45 
50 
55 
-
testing in wind tunnels. 60 
SUMMARY OF THE INVENTION 
In a preferred embodiment of the present invention, a 
reaction control system nozzle block is provided for 
testing the response characteristics of space vehicles to 65 
a variety of reaction control nozzle configurations. A 
thrusting medium is supplied to a plurality of supply 
lines, each of which leads to a particular jet nozzle. The 
L 
supply lines terminate in a cylindrical plenum volume 
provided immediately upstream of the throat of each jet 
nozzle, said cylindrical plenum being oriented perpen- 
dicular to the axis of said throat. The volume of the 
cylindrical plenum is selected to provide uniform thrust 
characteristics from each jet nozzle irrespective of the 
angle of approach of the supply line. A convenient 
means such as a plug or a cap is provided for selectively 
stopping the flow of thrusting medium to a jet nozzle 
and thereby enabling a variety of nozzle configurations 
to be obtained from a single model nozzle block. 
It is a feature of the present invention to provide a 
reaction control system test nozzle block which permits 
a variety of jet thruster test configurations to be ob- 
tained without introducing thrust alignment errors. 
It is another feature of the present invention to pro- 
vide a reaction control system nozzle block whose jet 
thruster configuration can be conveniently altered with- 
out recalibration of the altered configuration. 
It is st i l l  another feature of the present invention to 
provide a reaction control nozzle block wherein uni- 
form nozzle t h t  characteristics are obtained from 
each jet thruster. 
It is yet another feature of the present invention to 
provide a reaction control nozzle block wherein the 
nozzle thrust characteristics are independent of the 
entrance configuration of the supply line to the nozzle. 
BRIEF DESCRIPTION OF THE DRAWINGS 
In order that the manner in which the above recited 
features of the invention are obtained can be understood 
in detail, a more particular description of the invention 
may be had by reference to the specific embodiments 
thereof which are illustrated in the appended drawings, 
which drawings form a part of this specification. It is to 
be noted, however, that the appended drawings illus- 
trate only typical embodiments of the invention and 
therefore are not to be considered limiting of its scope 
for the invention may admit to further equally effective 
embodiments. 
IN THE DRAWINGS 
FIG. 1 is a perspective view of a reaction control 
system test nozzle block according to the present inven- 
tion. 
FIG. 2 is a cross-section illustrating a supply line at 
angle 8 to the nozzle entrance plenum. 
FIG. 3 is a cross-section view illustrating a supply 
line at angle 9 to the nozzle entrance plenum. 
FIG. 4 is a graph of the thrust characteristics of a 
reaction control nozzle for a variety of supply line ap- 
proach angles. 
FIG. 5 is a bottom view of a reaction control system 
test nozzle block showing a typical orientation for the 
nozzle supply lines. 
DETAILED DESCRIPTION OF THE 
PREFERRED EMBODIMENTS 
Referring now to FIG. 1 there may be seen a perspec- 
tive view of an assembled reaction control system test 
nozzle block 2. Nozzle block 4 is provided in a configu- 
ration to dispose nozzles 21 through 29 about the pe- 
riphery in a configuration to obtain control of the model 
about the pitch, roll and yaw axes. A plurality of noz- 
zles 21 through 29 are illustrated so that a variety of 
nozzle test combinations can be achieved from a single 
nozzle block 4. Connecting cylinder 6 surrounds supply 
lines 9 through 17 to align nozzle block 4 with the 
model being tested and to seal the entrance of the sup- 
4,091,665 
3 4 
Ply tubes 9 through 17 from the exterior of the cylinder with 0 varying from 0" to 30° and 4 varying from 0" to 
6. A seal ring groove 7 is provided for use with a con- 30". It may readily be seen from FIG. 4 that the test 
ventional"0 - ring or other conventional seal rings for thrust characteristics coincide with the reference thrust 
sealingly mating with a supply for a thrusting medium characteristics curve 44, indicating that the compact 
(not shown). Cylinder 6 is rigidly interconnected with 5 cylindrical plenum 34 provides the desired uniformity 
nozzle block 4 by support extension 8 to ensure precise of jet nozzle thrust characteristics. 
orientation of nozzle block 4 when cylinder 6 and sup- Referring now to FIG. 5, there may be seen a bottom 
port extension 8 are mated with the model to be tested. view of a reaction control test nozzle block assembly 2 
A thrusting medium, generally high pressure air for illustrating a typical internal arrangement and intercon- 
model testing, is simultaneously supplied to the top 10 nection of supply lines 9 through 17 and jet nozzles 21 
openings of all of the supply tubes 9 through 17 and through 29. Typical cylindrical throat inlet plenums 52, 
thereby fed to the jet nozzles 21 through 29 to which 54 and 56 are disposed adjacent jet nozzle throats 51,53 
each supply tube 9 through 17 is connected. A plug 19 and 55, respectively. It is evident that supply lines 9 
or a cap 20 may be provided for individually blocking through 17 intersect their respective plenums in a vari- 
the supply of the thrusting medium to selected jet noz- 15 ety of angular configurations. The method and appara- 
zles and altering the particular jet thruster configuration tus which are the subject of the present invention ensure 
to be provided for the test. that the thrust characteristics of jet nozzles 21 through 
Referring now to FIG. 2, there may be seen a supply 29 are independent of the entrance configuration of 
tube 32 entering plenum 34 at an angle 8. Plenum 34 is supply lines 9 through 17. Since there is no degradation 
of Cylindrical configuration and is disposed immediately 20 in the thrust characteristics for any particular entrance 
upstream of the throat 37 of the jet nozzle 36. It may be configuration, a variety of jet nozzle arrangements may 
seen that the axis of plenum 34 is oriented perpendicular be selected from the available jet nozzles 21 through 29 
to the axis of throat 37. Angle 8 is measured in a plane without any need to fabricate and calibrate each partic- 
perpendicular to the axis of cylindrical plenum 34 and ular jet nozzle arrangement for which it is desired to 
defines a first angle of approach for supply line 32. 25 obtain model test response characteristics. The alter- 
Referring now to FIG. 3, there may be seen a cross- ation of the jet thruster configurations can be done in a 
section elevation view of supply line 32 entering cylin- reversible fashion by the use of removable plugs 19 or 
drical plenum 34 at an angle 4. Angle I$ is measured in caps 20, (see FIG. 1) and the nozzle block assembly 
a plane parallel to the axis of cylindrical plenum 34 and may, therefore, be re-used. 
defines a second angle of approach for supply line 32. 30 Numerous variations and modifications may obvi- 
Referring again to FIGS. 2 and 3, a typical supply ously be made in the structure herein described without 
line 32 may approach the cylindrical entrance plenum departing from the present invention. Accordingly, it 
34 disposed behind jet nozzle 36 in a variety of combina- should be clearly understood that the forms of the in- 
tions of angle 8 and angle 4. In a reaction control sys- vention herein described and shown in the figures of the 
tem test nozzle block, it is desirable that the thrust char- 35 accompanying drawings are illustrative only and are 
acteristics obtained from nozzle 36 be independent of not intended to limit the scope of the invention. 
the angles 8 and I$ at which supply line 32 approaches 
nozzle 36. Energy losses associated with the supply line 
and entrance configuration of plenum 34 can affect the 
thrust characteristics of jet nozzle 36 if the plenum 
volume is too small. In a nozzle block for model testing, 
it is desired that the design of plenum 34 be such that the 
degradation in thrust characteristics of nozzle 36, if any, 
be minimized. As more fully shown hereinbelow, a 
compact cylindrical plenum 34, whose diameter and 
height are substantially equal, provides the required 
uniform thrust characteristics. 
It should be noted that FIGS. 2 and 3 illustrate a test 
configuration where jet nozzle 36 was fabricated in a 
separate plate which was then located in front of a 
selected plenum. In the reaction control system test 
nozzle block, other manufacturing techniques may be 
used in addition to forming the nozzles in a separate 
plate. For example, jet nozzle 36 may be formed in a 
solid block and plenum 34 formed by drilling a cylindri- 
cal cavity adjacent nozzle throat 37 and thereafter in- 
serting cylindrical plugs (not shown) in the cavity space 
where plenum volume is not desired. 
Referring now to FIG. 4, there may be seen a graph 
of the thrust characteristics of jet nozzle 36 in the test 
configuration illustrated in FIGS. 2 and 3. A reference 
configuration was tested comprising a large volume of 
thrusting medium disposed immediately behind throat 
37 of jet nozzle 36 to obtain the reference thrust perfor- 
mance 44. A theoretical thrust performance c w e  45 is 
also illustrated to indicate the magnitude of energy 
losses which occur Within jet nozzle 36. A variety of 
supply line 32 entrance angle configurations were tested 
What is claimed is: 
1. A multi-purpose nozzle assembly for reaction con- 
a nozzle block defining a plurality of jet nozzles dis- 
posed for control about at least one axis of said 
model, 
nozzle supply means for selectively connecting said 
jet nozzles to a thrusting medium, and 
plenum means disposed between said nozzle supply 
means and each said jet nozzle for obtaining thrust 
characteristics of each jet nozzle independent of 
the approach angle of said nozzle supply means. 
2. The nozzle assembly described in claim 1, wherein 
50 said plenum means comprises a cylindrical cavity de- 
fined by said nozzle block and disposed adjacent and 
perpendicular to the throat of said jet nozzle. 
3. The nozzle assembly described in claim 2, wherein 
the diameter of said cylindrical cavity is substantially 
4. The nozzle assembly described in claim 3, wherein 
said nozzle block defines a plurality of jet nozzles selec- 
tively oriented to provide control about the pitch, roll 
and yaw axes of said model. 
5. The nozzle assembly described in claim 4, wherein 
said nozzle supply means further comprises 
a cylinder for housing said nozzle supply means, and 
sealing means for sealingly interconnecting said cyl- 
inder with a source for said thrusting medium. 
6. The nozzle assembly described in claim 5, further 
a plurality of supply lines interconnecting said noz- 
trol testing of wind tunnel models, comprising 
40 
45 
55 the same magnitude as the height of said cavity. 
60 
65 
comprising 
zles with a thrusting medium, and 
5 
4,09 1,665 
6 
means for selectively blocking the flow of said thrust- 
h g  medium through said supply lines for providing 
a variety of nozzle configurations for model test- 
ing. 
7. The nozzle assembly described in claim 6, wherein 
said blocking means comprises plugs removably insert- 
able interiorly of said selected supply lines. 
8. The nozzle assembly described in claim 6, wherein 
said blocking meaDS comprises caps removably 
5 over the entrance of said selected supply lines. * * + * *  
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Multi-purpose wind tunnel reaction control model block

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