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Патент USA US2600049

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June 10, 1952
c. B. CONWELL
2,600,048 _
RIBBED CORE FOR STEEL BLADES
Filed Oct. 14, 1949
INVENTOR
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C O N w E \_ L
A T TO R N E Y
Patented June 10, 1952
2,600,048
UNITED. STATES PATENT‘
2,600,0481
RIBBEp coRnFoR STEEL BLAnns
Charles B. Conwell, GlastonhuryLCQnnu assignor
vto United Aircraft. Corporation, East Hartford,
0.012;!” a carpgraticnof Delaware
,
'
Application Octpber '14, 1949, Serial lfio. 121,331?
12. Claims. (01. 170-3159;)
1
This invention relates to hollow metal propeller
blades and more speci?cally to an improved core
construction for hollow steel blades. '
‘
It is an object of this invention to provide a
core construction for hollow metal propeller
blades wherein the sti?ness of both the core and
the surrounding blade cover is greatly improved.
' It is a further object of this invention to pro
2
.
faces or channels may be formedby passing the
core longitudinally between a pair of rollers or
may be produced by any form of crimping so‘ that
the lowermost portions of the depressions .will.
abut each other as, for example. at 40. as shown
in Figs. 4v and 5. The abutting. portionsgof the
depressions are then seam welded together there-q
by forming a longitudinally extending rib gen.-'.
vide a core vfor a hollow steel blade or the like
erally designated as 44 (Fig. 5). The rib 44 thus.
wherein the core is also hollow and contains at 10 formed provides additional longitudinal - ‘land
least one spanwise seam along at ‘least a portion
chordwise stiffness while impartingfurther rigid.
of the core thereby forming a plurality of longi
tudinally extending hollow members which com
ity ina direction transversely of the chord-ofthe
blade.
prise the strength member for the blade. These
The depression l8 as shown in Fig. .1. extends
and other objects of this invention will'become 15 from the tip end of the core member inboard to
readily apparent from the following detailed de
ward .the blade shank any desirable distance. De
scription of the accompanying drawing in which,
pending on the, structural characteristics desired.
‘ Fig. 1 is a plan view of a hollow steel blade hav
a plurality of such depressions may be utilized.
and if further desired, the depressions may extend.
‘Fig. 2 is a cross sectional view taken‘ along the 20 for a greater distance along the longitudinal axis
line 2--2 of Fig. 1.
'
of the core to provide added stiffness'toward the
"Fig. 3 is a cross sectional view taken along the
inboard end of .the blade.
'
'
line 3—3 of Fig. 1.
To complete the blade assembly, the outer cover
Fig. 4 is a cross sectional view taken along the
I2 is wrapped around the core portion l6 ‘so that
lined-4 of Fig. 1.
'
'
‘
25 the major surfaces 32 and 36 of the core portion
Fig. 5 is a cross sectional view taken along the
[Gare in continuous and intimate abutting rela
line 5-5 of-Fig. 1.
‘
'
'
‘
' >
tionship with the face sideill and the camber side
Referring to Fig. 1, a hollow steel propeller
52,. respectively, of the blade cover l2. The abut‘
blade is shown having a hollow core member gen
ting surfaces of the coreportion l6 and the'bla'de
erally indicated‘ at H) and an outer cover l2 ol’_v
covering [2 are ?rmly secured together by means‘
substantially airfoil shape. The core l0 come
of brazing or the like. Thetip portion 6001? the
prises a shank portion 14 and an elongated main
blade covering l2 and the trailing edge 62 thereof
portion l6 which is formed from a substantially
are formed by seam welding together the adjacent‘
ing a core constructed according to this invention.
tubular member and may have its wall thickness
tapering toward the tip portion of theblade was 35
edges of the blade cover I 2.
'
' '
‘ "
As a result of this‘invention a hollow blade
shown. ’
core construction has been provided for‘grea'tly'
The elongated portion 16 of the core member is
partially ?attened as shown in ‘Fig. 3 in' order that
the core member may‘ more intimately receive
improving the torsional rigidity of the blade while‘
also improving the outboard ?exural stiffness“
which in turn reduces the ?atwise vibratory
the outer blade cover or shell [2 as better seen in 40. stresses in the blade. The improved sti?ness in
Fig. 3. The end of the tubular portion l6 of the
core ‘Ill which is to be positioned adjacent the tip
the core is especially important in wideblades"
oi the blade is closed or? at?!) by completelypflat
tening‘ the tube in this area and seam weldingv the
Further as a result of this invention an im
proved blade core construction has been‘ pro-w
adjacent surfaces-together.
where torsional moments are apt'to be high. " ‘ ’
45. vided wherein increased strength is providedjiat
substantially
It is to be understood
littleyo'r no increase
that‘the‘in
particular
Weight.‘ con
'
assembledthe tubular
'
'
'
'
‘ ‘ "
‘
‘
In. orderto increase-the stiffness of the core
and the blade when ?nally
core portion I6 is‘ crimped along its longitudinal
struction ‘described is readily adaptable to otherv
axis to the extent that a longitudinal ‘depression
metal blades as well as hollow steel blades.
"
50.
generally designated ‘as I8 is formed in‘each ‘of
Although only one embodiment of this inven
the major surfaces ‘of the ?attened‘tubular mem
tion has been illustrated and described herein, ‘it
ber. Thus a depressed surface 30 (Fig. 4) will be
will be apparent that various ‘changes
mm:
formed ‘in the surface32 of the core portion, l6
?cations maybe made in _the_confi'guration , and
and Tan bpposineidepreseed 511mm,“ will be
formed in‘ the surface“; “ These depressed sure
arrangement of the ‘component palrtSiWiPhe?t (19.1.
parting-from thescope of this novel concept:
‘
2,600,048
4
3
wise surfaces, an airfoil shaped cover surrounding
What is desired by Letters Patent is:
said core and secured thereto in juxtaposed rela
tion with a majority of said surfaces, and means
for stiffening said blade comprising at least one
spanwise depressed surface portion on at least
one major surface of said core located inter
1. In a hollow metal propeller blade, a hollow
core member having two major, upper and lower
spaced spanwise surfaces, an airfoil shaped cover
surrounding said core and secured thereto, said
cover and said core being in juxtaposed relation,
and means for stiffening said blade comprising
at least one spanwise depression in each major
mediate the leading and trailing edges of said
core, said depressed portion being juxtaposed rela
tive to and fixed to the other of said major sur
surface of said core located intermediate the lead
ing and trailing edges of said core said depressions 10 faces continuously along its length said portion
having a chordwise dimension less than the chord
having a chordwise dimension which is less than
wise dimension of the juxtaposed core and cover.
the chordwise dimension of the adjacent jux
7. Means for stiffening an aircraft propeller
taposed surfaces of the core and cover.
2. In a hollow metal propeller blade, a hollow
core formed of a tubular metal member having
surface of said core located intermediate the lead
ing and trailing edges of said core, the depressed
portion in one of said surfaces being disposed ad
jacent the depressed portion in the other of said
peller blade, the steps comprising, partially flat
core member having two major spaced spanwise 15 a flattened cross section to provide two major
sides spaced from each other comprising, a com~
surfaces, an airfoil shaped cover surrounding said
paratively narrow central spanwise extending
core and secured thereto substantially through
portion of said‘ sides abutting and secured to
out said major surfaces, and means for stiffening
gether said portions having a chordwise dimen
said blade comprising at least one spanwise de
pression in one of the major surfaces of said core 20 sion less than the chordwise dimension of said
sides.
located intermediate the leading and trailing
8. In a one piece hollow core member for a hol
edges of said core, the lowermost portion of said
low metal propeller blade having a surrounding
depression being in juxtaposed relation to the
cover of airfoil shape secured thereto along a
other of said major surfaces and ?xed thereto
continuously along the length of said depression, 25 spanwise axis, means for stiffening said core com
prising at least one cooperating pair of longitu
said depression having a chordwise dimension
dinal depressions on opposed surfaces of said
which is substantially less than the chordwise
core located intermediate the leading and trail
dimension of the adjacent major surface of said
ing edges of said core, with the chordwise dimen
core member.
3'. In a hollow propeller blade, a hollow core 30 sion of said depressions being less than the chord
wise dimension of the remainder of the core, said
member having upper and lower spaced major
cooperating depressions being in juxtaposed rela
surfaces, an airfoil shaped cover surrounding said
tion, and means for securing said depressions to
core and secured to said major surfaces, and
gether.
means for stiffening said blade comprising at least
9. In a method of making a hollow metal pro
one spanwise depressed portion in each major 35
surfaces, said depressed portions having chordwise
tening a tubular metal member throughout a
major portion of its length to form a core for the
blade, forming longitudinal channels in opposed
40
dimensions less than the chordwise dimension of
the adjacent major surfaces, and means for se
curing said portions together continuously along
their length.
4. A hollow metal propeller blade comprising a
tubular core having two spaced apart major sur
faces and a sheet metal airfoil forming covering
member surrounding and secured to said major
surfaces of the flattened member whereby the
lowermost portion of the channel on one surface
abuts the lowermost portion of the channel on
the opposite surface, securing said abutting por
tions together to thereby increase the stiffness
- of said core, surrounding said core with a metal
cover of airfoil shape to form the face and camber
sides of said blade, and securing said cover to said
core along the opposed flattened surfaces of said
core.
surfaces of said core, said core having a ?at
10. In a method of forming a metal core for a
tened cross section to provide two major sides,
hollow propeller blade, the steps comprising, par
and a reinforcing rib for said core comprising
tially flattening a hollow tubular member along
opposed spanwise extending channels in said
a majority of its length, sealing the end of said
major sides located intermediate the leading and
tube which will be positioned adjacent the tip of
trailing edges of said core, said channels being
arranged in abutting relation and secured to 65 the blade, forming at least one spanwise corruga
tion in the opposed flattened surfaces of said
gather, the chordwise dimension of said chan
tubular member so that the depressed portion of
nels being less than the chordwise dimension of
the corrugation in one of said ?attened surfaces
each of said major sides.
abuts the depressed portion of the corrugation in
5. In a hollow metal propeller blade, a span
wise core member having two major spaced apart 60 the other of said surfaces, and securing said abut
ting portions together.
spanwise surfaces, an airfoil shaped cover sur
11. A method according to claim 10 wherein
rounding said core and secured thereto, said sur
the corrugations are formed to extend fromthe
faces being in juxtaposed relation with said cover
sealed end of said tubular member inboard along
and means for stiffening said blade comprising at
least one spanwise depressed surface portion on 65 a portion of the length of the tubular member.
, 12. In a hollow metal propeller blade, a par
each major surface of said core located inter
tially ?attened tubular core member comprising
mediate the leading and trailing edges of said
a closed tip portion and having an elongated
core, the depressed portions on respective surfaces
channel formed in opposed cooperating relation
being formed in opposed relation to each other,
the chordwise dimension of said portions being 70 in each of the major surfaces of said core inter
mediate the leading and trailing edges of said
less than the chordwise dimension of the adjacent
core and extending inboard from said tip portion,
juxtaposed portions of said surfaces and cover,
said channel being formed of sumcient depth so
and means for securing said portions together.
that the bottom of the channel in the one ofv
_ 6. In a hollow metal propeller blade, a span
wise core member having two spaced major span- ’
said major surfaces abuts the bottom of the chans- _
5
2,600,048
6
nel in the other of said surfaces, means for se
Number
curing together the abutting portions of said
channels continuously along the length of the
latter, a cover of airfoil shape surrounding said
core and having a portion of its inner surface in 5
intimate contact with said major surfaces, the
chordwise contact length of said inner surface
and said major surfaces being greater than the
chordwise dimension of said channels, and means
for bonding said cover to said core.
10
‘CHARLES B. CONWELL.
REFERENCES CITED
2,122,709
2,262,163
2,362,301
2,465,007
2,469,480
2,511,858
2,511,862
2,512,264
2,514,525
2,523,216
2,535,917
2,541,661
The following references are of record in the
15
?le of this patent:
UNITED STATES PATENTS
Number
Name
Date
1,994,725
Offutt __________ __ Mar. 19, 1935
Name
Date
Barkley __________ __ July 5, 1938
Brauchler ________ __ Nov. 11, 1941
Pecker ____________ __ Nov. '7, 1944
Bragdon et a1. ____,___ Mar. 22, 1949
Sikorsky ________ .._ May 10, 1949
Lampton ________ __ June 20, 1950
Martin __________ __ June 20, 1950
Brauchler ________ __ June 20,
Stulen __________ __ July 11,
Isaceo ______ _,.____ Sept. 19,
Gruetjen ________ __ Dec. 26,
Palmatier ________ __ Feb. 13,
1950
1950
1950
1950
1951
FOREIGN PATENTS
Number
178,168
15,656/28
Country
Date
Great Britain ____ __ Mar. 31, 1922
Australia __________ __ May 7, 1929
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