Channel-type shell construction for rocket engines and related configuration

Baehr, E. F.

English

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CHANNEL-TYPE SHELL CONSTRUCTION FOR ROCKET ENGINES AM) THE LIKE 
Filed March 5, 1962 
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(PAGES) ( C ~ D E )  
( N ~ A  CR OR TMX OR AD NUMBER) (CATEGORY) 
ATTORNEY 
https://ntrs.nasa.gov/search.jsp?R=19700025544 2020-03-17T02:05:26+00:00Z
3,120,101 United St ffice Patented Feb. 4, 1964 
1 2 
radially outwarcl. Binding means in the form of strength- 
ening members encircle the exterior of the enclosure ad- 
jacent the ends of the ribs to form a skin which defines 
with the channels a series of coolant passages that sur- 
the United 6 round the enclosure and extend longitudinally thereof. 
In accordance with the invention, a capstrip is interposed 
provide increased shear area. Each capstrip includes a Filed Mar. 5, 1962, Ser. No. 174,684 
(Granted under Title 35, U.S. Code (1952), sec. 266) pair of opposed flanges having flat faces for contacting 
10 the skin and a pair of legs having planar surfaces for 
The invention described herein may be manufactured engaging the sides of the channel rib. The flanges are 
and used by or for $the Government of the United states connected by a web that is deformable SO that as the cap- 
of America for governmental purposes without ithe pay- strip is formed, the planar surfaces on the legs are spread 
menl of any royalties thereon or therefor. apart for positioning on the contiguous channel ribs. 
This invention d a t e s  to a lightweight wall construction 15 After assembly, the capstrip is rolled to move the flat sur- 
utilizing contiguous structunaJ aomponents bent to a pre- faces into coplanar relationship thereby pinching the 
determined configura,tim, and more particdmly to an im- channel ribs between the planar faces. 
proved channel-type shell having capstrips at the joints Referring now to FIG. 1, there is shown a combustion 
between adjacent channels. chamber 10 and nozzle 11 for a rocket motor fabricated 
The invention is primarily cornernod with the type of 20 from a plurality of structural components such as chan- 
structure shown in Patent No. 2,943,442 whi& discloses nels 12 formed from a material capable of withstanding 
a chamber comprising a plurality of contigums channels the operating temperatures as well as the corrosive action 
with the abutting ribs extending radially outward and bind- of the rocket propellants. The channels 12 are con- 
ing means such as wire encircling a e  exterior Qf the cham- tiguously arranged and secured together to form a hollow 
ber to form a skin for strengthening the structure. The 25 enclosure which constitutes the combustion chamber and 
wrapping wire is secured to the edges of the ribs to form a nozzle. 
series of passages surrounding the chamber and extending Each of the channels 12 has a pair of parallel ribs 14 
longitudinally thereof through which propellant is circu- which extend radially outward from the hollow enclosure, 
lated for regeneratively ooding the chamber. For opiti- as shown in FIG. 2. The ribs 14 of adjacent channels 
-chajmels in the 30 12 abut one another and are secured together by a suit- mum heat transfer the thickness 
slq&_strzctuse m u s l b e  as thh' However, in able brazing material during the fabrication of the en- 
the structure illustrated in the a b v e  patent this thickness closure. A ribbon 16 shown in FIG. 3 of a high strength 
is determined by the amount of 'material required to pro- I material is wrapped about the assembled channels 12 to 
vide the necessary joint strength from the butt braze ofp form an outer skin 18 shown in FIG. 1. The skin 18 
the rib edges to the wire wrap. Because this joint limits 135 defines with the channels 12 a series of coolant passages 
the allowable dms in the channel material to a value '\ 20 around the enclosure which extends longitudinally 
much lower than the yield strength, the weight of the for the circulation of propellants during regenerative cool- 
material for a given operating pressure is normally ex- ing of the combustion chamber 10 and nozzle 11. 
cessive. According to the invention, a plurality of capstrips 22 
It is, therefore, an Iobject of the present invention to 40 are interposed between the channels 12 and the skin 18 
provide an improved wall structure utilizing extremely thin to provide a greater bonding area. Each capstrip 22 corn- 
channels contiguously arranged with a skin enclosing the prises a pair of opposed flanges 24 and 25 connected by 
channels t~ form coolant passages. a centrally disposed web 26. A pair of spaced legs 28 
Another object of the invention is to utilize capstnips and 29 extend downwardly from the web 26, as shown in 
in a regeneratively-cooled combustion chamber which pro- 45 FIGS. 2 and 3. The leg 28 is integral with the flange 24 
vides for increased shear area between the structural corn- while the leg 29 is likewise integral with the flange 25. 
ponents of the chamber and the enclosing skin. The flange 24 has a generally flat surface 30 for engag- 
A further object o€ the invention is to provide an im- ing the inner surface of the skin 18 while the opposed 
proved wall structure by interposing a capstrip between flange 25 has a similar surface 31. A generally planar 
contiguous channels land the adjacent strengthening mem- 60 surface 33 is provided on the leg 28 while a similar sur- 
bers for increasing the bonding area between the ribs of face 34 is provided on the leg 29 for engaging the sides 
Dhe channels and the skin formed by the strengthening of a pair of adjacent ribs 14. 
members to enable the material of the channels to be used Each capstrip 22 is roll-formed or extruded in a long 
efficiently at high working stress levels. continuous length that is subsequently cut to the required 
Other objects of the invention will be apparent from the 55 lengths by suitable means such as an abrasive cut-off 
specification which follows and from the drawings where- wheel to prevent the distortion of the cross section. After 
in like numerals are used throughout to identify like parts. the capstrip 22 is formed, it may be electroplated with 
In the drawings: copper or other suitable brazing alloy before or after 
FIG. 1 is a perspective view of a chamber that is con- cutting. The alloy may also be applied to the ribs 14 in 
structed in accordance with the invention showing the as- 60 the form of a ribbon or foil. 
sembly at  the fabrication stage preparatory to forming an Because of its thickness the web 26 is deformable and 
outer skin; as the capstrip 22 is formed the surfaces 30 and 31 on the 
FIG. 2 is an enlarged sectional view of a portion of the flanges 24 and 25, respectively, are angularly disposed to 
shell construction taken from the position indicated by each other. Inasmuch as the planar surface 33 is normal 
the line 2-2 in FIG. 1; and 65 to the flat surface 30 and the planar surface 34 is normal 
FIG. 3 is an enlarged sectional view of a portion of the to the flat surface 31, the planar surfaces 33 and 34 are 
shell construction taken from the position indicated by the angularly disposed to one another as the capstrip 22 is 
line 3-3 in FIG. 1. formed. This enables the capstrip 22 to be readily as- 
The aforementioned objects are achieved by providing a sembled over the ribs 14, as shown in FIGS. 1 and 2. 
combustion chamber with a plurality of elongated chan- 70 After the capstrip 22 is assembled on the abutting ribs 
nels contiguously arranged and secured together to form of the contiguous channels 12, the flat surfaces 30 and 31 
a hollow enclosure with the ribs of the channel extending are rolled to remove the dihedral therefrom by moving 
3,120,101 
CHANNEL.TYPE SMELL CONSTRUCTION FOR 
ROCKET ENGINES AND THE LIKE 
States Of America as represented by the Adminisbrator 
Edward F. Baehr, Berea, Ohio, SSSifPOr 
Of the National Aeronautics a d  space Admmbation between contiguous pairs of the channels and the skin to 
3 Clalms. (421. 60-35.6) 
I 
---_. 
3,120,101 
4 
a ribbon encircling said assembly and adapted tqdefine 
with said channel members a plurality of longitu- 
dinally extending passages for regenerative cooling, 
a plurality of elongated cap strips in engagement with 
the outer portions of said ribs for providing a greater 
bonding area between said ribbon and said assembly, 
each cap strip including 
a pair of opposed flanges for facewise contact with 
the inner surface of said ribbon, 
a pair of substantially parallel legs for facewise con- 
tact with the side walls of adjacent ribs, 
a deformable web between said flanges providing said 
cap strip with an initial configuration wherein said 
legs extend at a slight acute angle to each other and 
a final configuraton wherein said legs lie in substan- 
tially parallel closely spaced planes, 
means rigidly securing said flanges to said closure 
means when said cap strip has said final configura- 
tion, and 
means rigidly securing said legs to said ribs when said 
cap strip has said final configuration. 
2. A rocke motor casing as claimed in claim 1 wherein 
the flanges have substantially planar contact faces to 
achieve maximum bonding. 
3. A rocket motor casing as claimed in claim 1 wherein 
the legs have substantially planar contact faces to achieve 
maximum bonding. 
References Cited in the file of this patent 
UNITED STATES PATENTS 
3 
these surfaces into a coplanar relationship. This moves 
the surfaces 33 and 34 into a parallel relatidnship which 
pinches these surfaces against the faces of the abutting 
ribs 14, as shown in FIG. 3, because the spacing between 
the surfaces 33 and 34 in the parallel position is equal to 5 
the distance between the faces of the abutting ribs. 
The ribbon 16 is wrapped around the contiguous chan- 
nels 12 from the end of the combustion chamber 10 to the 
end of the nozzle 11 to form the skin 18 after all of the 
capstrips 22 have been secured to the ribs 14. The rib- 10 
bon 16 has a brazing alloy on the surface which contacts 
the surfaces 30 and 31 of the capstrips 22, and the entire 
assembly is heated to a temperature adequate for brazing 
after the channels 12 have been completely wrapped. 
If desired, the brazing alloy may be in ribbon form and 15 
applied before the channels are wrapped. 
Whiie the preferred embodiment of the invention has 
been disclosed and described, it will be appreciated that 
various modifications may be made to the disclosed struc- 
ture without departing from the spirit of the invention or 20 
the scope of the subjoined claims. For example, a high 
strength wire, the type described in U.S. Patent No. 2,943,- 
442 may be substituted for the ribbon 16 shown in FIGS. 
2 and 3. 
What is claimed is: 
1. A rocket motor casing comprising, 
an assembly of elongated channel members extending 
1on:itudinally and arranged in contiguous annular 
relation, the webs of said channel members constitut- 
ing the inner surfaces of the wall of said casing, the 30 
ribs of said channel members extending generally 164,379 Kloman --_-__--________ June 15,1875 ! 
radially outward with adjacent ribs secured together Baehr __-_-______-_______ July 5, 1960 
to produce a unitary construction, 2,955,415 Long -----______________ Oct. 11,1960
25 
i 
2,943,442 


Channel-type shell construction for rocket engines and the like Patent

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