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Патент USA US2406551

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Aug. 27, 1946.
C. E. LUCKE
2,406,551
CYLINDER COOLING STRUCTURE FOR AIRCRAFT ENGINES
Filed Aug. 28, 1945
2 Sheets-Sheet l
27 24 2a 22
ATTORNEY a
- Aug. 27,1946.
..¢. E'LU‘CKE‘
'
.
1 2,406551
CYLINDER QOOLING STRUCTURE FOR'iAIRCRAFT ENGINES
Filed Aug. 28, 1945
2 Sheets-Sheet 2
INVENTOR
L?HPIBSEZZIL'KB.
“M rm K
ATTORNEY
Patented Aug. 2'77, 1946
2,406,551
UNITED STATES PATENTgOFFICE
2,406,551
CYLINDER COOLING STRUCTURE F0
>
AIRCRAFT ENGINES
<
‘
Charles E. Lucke, New York, N. Y., ,as'signor, to
United Aircraft ‘Corporation, East Hartford,
Conn, a corporation of Delaware
‘
.
Application August 28, 1943,v Serial No. 500,334
16 Claims.
1
(01.‘123-171)
This invention relates to air-cooled aircraft
2
Fig. 2 is a side elevation,‘ partly in section, of
engines and particularly to improved and eili
the cylinder shown in Fig. 1.- ‘
cient cooling means for the engine cylinders so
that the walls thereof may be uniformly cooled
Figs. 3 and 4 are fragmentary sectional views
taken respectively on the planes of lines 3—3 and
circumferentially.
_
.
A primary object of the present invention is to
provide improved air cooling means for internal
combustion engine cylinders of the aircraft type
in which the cooling air is constrained to now
5
4—4 of Fig. 1.
'
Fig. 5 is a view similar to Fig. 1, showing an
other form of the invention
Fig. 6 is a side elevation, partly in section‘, of
the form of the invention shown in Fig. 5.
transversely about the cylinders, the constraining 10 Figs. 7 and 8 are fragmentary’sectional views
means causing the air to closely follow the cir
taken respectively on the planes of lines 1—'l and
cumference of the cylinders to equalize the cool
8—8 of Fig. 5.
'
I
ing effect of the air upon their down stream sides,
Fig. 9 is a transverse sectional view of a cylin
with that on the up stream side in spite of the
der similar to Fig. 1 but showing a still further
higher air temperature on the down stream side. 15
form of the invention.
.
A feature of the invention that is desirable is
that the enclosing means for constraining the air
shown in Fig. 9, parts being broken away to more '
at its admitting portion has a'relatively large air
clearly show the cooling ?ns.
Fig. 10 is a partial side elevation of the cylinder
flow area adjacent the air intake which is grad
Fig. 11 is a vertical sectional view taken on the
ually reduced through the air duct to cause an 20 plane of line I l—ll of Fig. 9.
increase in the product of density and velocity
of the air as it passes around a cylinder and ?nal
ly is exhausted from the down stream side there
of. The product of density and velocity is re
ferred to as mass ?ow throughout the speci?ca
tion.
~
Another feature of the invention that is im
po’rtant is that the coolingv of the portion of the
Figs. 12 and 13 are fragmentary sectional views
taken respectivelyon the planes of lines lZ-l2
and l3—l3;in Fig; 9.
i Fig. 14 is a transverse sectional view of a cylin
25 der similar to Fig. 1 but showing a still further
form of the invention.
Fig. 15 is a side elevation, partly in section, of
the cylinder shown in Fig. 14; and,
,
cylinder surface extensions exposed to the rush
Fig. 16 is a side elevation partly in section of
of air is equalized between up and down stream 30 the cylinder shown in Fig. 14 and taken on the
sides by increasing the area of metal exposed to
plane of line [6-46 in Fig. 14; this view showing
the cooling air on the down stream side and by
the varying thickness circumferentially of th
increasing the amount of air to pass over these
down stream areas.
?ns about the cylinder.
>
In ‘the standard vforms of air-cooled aircraft
Another object of the invention is to provide 35 engine
cylinders cooling on the upstream side
simple forms of air cooling means particularly de
greatly
exceeds that on the downstream side.
signed for aircraft engine cylinders and e?ecting
The temperature di?erence between the opposite
substantially maximum uniform cooling circum
sides of a cylinder caused by this uneven cooling
ferentially of the cylinder walls.
. .
And ?nally it is another primary object of the 40 may be great enough to cause a distortion from
invention to provide an extended surface ?n or
equivalent structure surrounding an aircraft en
gine cylinder and enclosed within a cow] or jack
et, this structure effecting maximum uniformity
in cooling the walls circumferentially of the cyl
inder.
.
‘
‘
Other objects and advantages will be apparent
fromv the speci?cation and claims and from the
the circular to an ovate section and impainthe
action of the piston contact with the walls and
its lubrication. The present invention equalizes ‘
the amount of- cooling on the upstream side and
on the downstream side of the cylinder, the result
being that the cylinder walls are substantially
uniformly'cooled about their entire circumfer
ence and it remains circular. An increased cool-L
drawings which illustrate what are now consid
ing on the downstream side is effected by con
ered to ‘be preferred embodiments of the inven
tion
In the drawings,
Fig. 1 is a transverse sectional view of an ‘air
50 straining the air admitted at the intake to the 4
‘craft engine cylinder provided-with one form of
and amount of metal in the ?ns on the down
65 stream side of the cylinder andby gradually in
;,the present invention."
‘
‘-
-
inter-?n spaces to flow transversely completely
about the downstream side of the cylinder, also
this cooling is increased by increasing the ?n area
2,406,551
3
4
.
shown in Figs. 1 to 4. As indicated most clearly
in Fig. 5 thesetarcuate members 22 near the air
intake portion 23 are at the outer ends of the
Lcreasing the air mass ?ow as it passes‘: through
the air duct.
In its preferred forms the invention may in
clude the‘ following principal parts: First, a
‘cylinder having a plurality of thin circumfer
radially outstanding ?ns 2| and, as these mem
bers 22 extend circumferentialy toward the ex
haust portionvzdvthey contact intermediate por
tions of the ?ns 2| and‘ atthe exhaust portion
ential radially. extending ?ns; second, substan
atially semi-circular'jacket or cowl members en
24 substantially one half of the ?ns‘ 2| are out- I
3closing portions of said ?ns and providing open
side the jacket formed by these members, the
ings for the intake and exhaust of cooling air
fto and from the air duct or inter-?n spaces
. within the jacket; third, supplemental ?ns with!
]in the air duct distributed principally, about the
‘downstream portion of the cylinder; and-fourth,‘ » .
L ?ns supported on or formed integrallywith the ‘ 7.
remaining portions being within these jacket
members. "Po-induce air to pass between the outer
portion of the ?ns 21 additional substantially‘
semiec'ylindrical eccentric jacket members 25 are
provided. Intakes for these supplemental jacket
‘jacket‘members and extending into the air duet.
members .25 may be extended laterally beyond
Referring more in detail to the ?gures of the
the circumferential ?ns 2| to admit maximum air
to the space between the outer ends of the ?ns
‘ drawings and ?rst to the form of‘in-vention shown '
in Figs. 1 to 4, it will be seen that the ‘cylinder
‘ I0 is provided with a jacket surrounding and
2! beyond the jacket portions 22. The. exhaust
openings 21 for the spaces between the jacket
The jacket as 20 members 22 and the supplemental members 25, .
as shown in Fig. '5 may be adjacent and on oppo
:will be seen in Figs. 1 and 2 is formed of two
site sides of the main exhaust opening 24. Dia
1 symmetrical substantially semi-cylindrical mem
phragms v2'8 may be utilized as in the previously
bers“ each partially surroundinethc cylinder
described form of the invention to, divide the
1 ‘ID at a uniform distance'therefrom, there ‘being -
' partially enclosing the ‘cylinder.
I openings l2 and i3 formedjbetween the ends of
1 these jacket members’ ll for the intake and ex
haust respectively ofrair passing between the
jacket and cylinder walls.
'
'
'
_ Circumferential ?ns M are provided on the out
‘ side surface‘of the cylinder [0 integrally formed
‘ thereon‘or welded or brazed thereto so that they
are thermally united thereto. As shown in Fig. 1
‘ ‘these ?ns are shorter adjacent the air admit
‘ ting ‘end l2 and are of gradually increasing radial
j length about the cylinder Ill and toward the ex
‘ haust opening l3.
As shown ‘most clearly in Fig. 1 the outstand
‘ ing ?ns In on the cylinder [0 are entirely cut
away" at the intake side I2 of the cylinder and
extend the full distance between the cylinder l0
j and jacket members ‘II, at the exhaust side 13
. of the cylinder, the length of the ?ns l4 grad
ually increasing from the intake to the exhaust
sideas more clearly- shownin the sections; Figs.
3/ and 4-. ~Therefore, the area and mass; of the
air-swept metal ?ns l4 gradually increase along
‘ the air duct and as the {temperature of the cool
stream of air as it enters the air duct;
'
' The form of the invention shown in Figs. 9 to
'13 has its cylinder 30 provided'with uniformly
spaced fins 3! of uniform radial length through
out the circumference. Surrounding these ?ns
3! and thermally united thereto at their outer
ends are arcuate jacket members 32. Intake and
exhaust openings .33 and 315 are provided as in the
other forms of the invention previously described.
ixtending inwardly from the inner surface of the
it jacket‘ members 32 are ?ns 35 of varying radial
length or height. Adjacent the intake portion
33 they are of but slight extent and their length
increases symmetrically on opposite sides toward
the exhaust opening 34, As seen in Figs. 9 and’
. 10 these inwardly extending ?ns'35; are continu
ous across the ‘exhaust opening between the two
cowl members 32 up ‘to the diaphragm 36. ' y
In Figs. 14, to 16 is. ‘shown a ‘form of the in
vention inwhich a series of uniformly spaced ?ns
4| having uniform radial height extend circum
ferentially about the. cylinder 40 to which they
maybe thermally united. Surrounding these iins
4| are arcuate jacket members 42 as in the pre
5 ing air passing the?ns-inoreases.
Extending radially inwardly from the jacket
1 members Hare circumferential ?ns l5‘preferably
and as-shown in Figs. '1 to -4 extending the entire
distance between the cylinder’ wall and jacket
. and completely encircling ‘thecylinder. These
viously described ‘forms of the invention.
As
shown in Fig. 16- the ?ns ‘4|. are of increasing
thickness .circumferentially of the cylinder from
the intake ‘portion 43 to the exhaust portion 44
so that the spaces between the ?ns for the air
adjacent the intake are relatively wide. and ad
?ns ‘[5. may be thermally united to the jacket ..
‘ members H by being welded or brazed thereto 55 jacent the exhaust are relatively narrow. Thus,
the mase?cw of the air passing through the air
. and enter. thev spaces between adjacent ?ns. l4
‘ extending .outwardlyfrom the cylinder “1.. Fins .
duct increases uniformly fromintake to exhaust,
l?may contact or maybe brazed to the cylinder
also the amount of metal incontact with the cool
ing air increases vduring the passage of theair
‘ wall. 1% at. their inner periphery.
.
‘The, inter-?n spaces are divided centrally. in
the. direction of flow of the. cooling air by axially '
f extending diaphragm, 16., one inserted- centrally
l oi the intakeopenine I2 and another inserted
. centrally of the exhaust opening l3.
By means -
through the air duct. Diaphragms45 are similar
to those previously described and may be inserted
‘in the intake and exhaust openings 43 and M.
In each of the above described forms of the
invention there is a relatively open space within
or these diaphragms I6 the stream of air is cen 65 the jacket members and between the ?ns adja
cent the air intake on the upstreamv side of" the
‘ trallydiv-ided as it enters the up stream end inter.
.
spaces.
7 The form of invention shown in Figs. 5 to 8' has
1 its cylinder 23 provided with uniformly spaced
circumferential fins 2! of equal. radial length
‘ throughout its circumference. vInterposed ‘be
3 tween adjacent ?ne 2i are arcuate strips 22 united
‘ along their upper and lower edges to opposite
surfaceeioi adjacent?ns 2'. and collectively form;- -
cylinder, this open space gradually decreasing
faround thercylinder in both directions toward the
‘exhaust ‘opening at the downstreamv side of the
‘cylinder. By reason of this reduction within the
inter-?n space for the cooling air the mass flow
of the air asit passes through the inter-?nspace
uniformly increases. Less ?n. surface area is ex
posed‘to the'cooling air at and ‘adjacent the in)
1 ing ‘jacket members generally similar to ‘those 75 take ‘Where the air is coolest'but thisiarea' and
2,406,651
6
cylinder barrels comprising a plurality of closely
adjacent circumferential heat radiating ?ns
thermally united to the barrel, cowl members
as the air passes through the inter-?n ‘spaced
toward the exhaust. At the exhaust end and por
tions adjacent thereto; the ?n area and metal
of‘ the ?ns is at a maximum. Also the mass ?ow
of airas it passes through the inter-?n spaces
gradually increases.
,
‘ 1' 6. Temperature equalizing means for engin
the‘ amount of heat'conducting metal in the ?ns
is materially increased gradually and uniformly
_ partially surrounding the barrel for oon?ningthe
air?ow to the inter-?n spaces, and annular ?ns
thermally united to said cowl members extending 1
within the sapce between the barrel and the cowl ‘
I
members, the area of said ?ns increasing gradu
' 'It'is to be'understood that the invention is not
limited to the speci?c embodiments herein illus 10
trated and described, but may be used in other
ally in the direction of air?ow.
’
'
7. In a cooling arrangement for internal com
bustion engine cylinders, the combination with a
cylinder barrel ofsa plurality of annular cooling
?ns-surrounding said barrel, cowl members par
I claim:
'
1." In a cooling arrangement for internal com 16 tially surrounding said ?ns and thermally united
thereto, said cowl members providing diametri
bustion engine cylinders,'thecombination with a
cally opposite openings'for the intake and ex
cylinder barrel, of a plurality of annular cooling
haust of air to and from said inter-?n spaces, and
?ns comprising two groups surrounding said bar
?ns provided on said cowl members, the amount
rel, cowl members partially surrounding said ?ns
and providing intake and exhaust openings for V20 of ?n metal exposed to the cooling air increasing
within the inter-?n spaces in the direction of the
the cooling air, one of said groups of ?ns extend
'?ow of air th'erethrough.
ing from the cylinder wall to said cowl through
8. In a cooling arrangement for internal com
out their circumferences, and the second group
bustion engine cylinders, the combination of a
‘being reduced in radial length throughout a por
tion of their circumferences, contacting surfaces "25 cylinder barrel, of a plurality of annular cooling
?ns surrounding said barrel and thermally united
of said ?ns and cowl members being thermally
thereto, cowl members partially surrounding said
united, said second group of ?ns increasing in
?ns and providing intake and exhaust openings
area toward said cooling air exhaust opening.
ways without departure from the spirit of the
invention as de?ned by the following claims.
for the inter-?n spaces, some of said ?ns being
'2. In a cooling arrangement for internal com- _
thermally united to said barrel and cowl and
other ?ns being united to one only'oi said mem
bers, whereby the free space between the ?ns ad
jacent the intake opening is greater than adja
cent the exhaust opening and the area of said
?ns gradually increases toward the exhaust open
bustion engine cylinders, the combination with a
cylinder barrel of a plurality of annular cooling
?ns surrounding said barrel and thermally united
thereto, cowl members partially surrounding said
?ns and providing intake and exhaust openings ,1
for said inter-?n spaces, and a plurality of annu
lar ?ns thermally united to said cowl members‘
and extending into said inter-?n spaces, the area
of said ?ns thermally united to said cowl mem
bers gradually increasing in area toward the cool
ing air exhaust opening.
.
ing.
,
»' :9.’ In a cooling arrangement for internal com
bustion engine cylinders, the combination with a
cylinder barrel, of a plurality of annular cooling
40 ?ns surrounding said barrel and thermally united
3. In a cooling arrangement for internal com
‘thereto, built-up cowl members disposed between
bustion engine cylinders, the combination with a
cylinder barrel of a plurality of annular cooling
?ns surrounding said barrel and thermally united
length whereby portions of said ?ns extend radi
ally beyond said cowl-members, said cowl mem
adjacent ?ns at variable distances along their
bers forming intake and exhaust openings on op
posite sides of said barrel, and supplemental cowl
?ns and providing intake and exhaust openings
members
surrounding and enclosing the extend
for the inter-?n spaces, some of said ?ns being
ed portions of said ?ns.
reduced in radial length, whereby the free space
10. In an air cooled internal combustion engine
between the ?ns adjacent the intake opening is 50 cylinder
in which the cooling air ?ows tranversely
greater than adjacent the exhaust opening, the
across and around said cylinder, the combination
area of said ?ns gradually increasing and. the‘in
of externally extended thermally integral metal
ter?n space decreasing toward the exhaust open
members in the path of the cooling air, a jacket
1118‘.
,
having inlet and outlet openings and enclosing
4. Temperature equalizing means for engine 55 the air stream, and means for equalizing the
cylinder barrels comprising a plurality of closely
temperature of the cylinder wall circumferen
adjacent circumferential heat radiating ?ns ther
tially thereof, said means comprising a circum
mally united to the barrel, means for con?ning
ferentially decreasing air ?ow area between said
the air ?ow to the inter-?n spaces, and means
inlet and outlet openings.
to increase the mass velocity of the air during its 60
11. In an air cooled internal combustion en
course through the inter-?n spaces, said ?ns
gine cylinder in which the cooling air ?ows trans
gradually increasing in area and said inter?n air
versely across and around said cylinder, the com
thereto, cowl members partially surrounding said
spaces decreasing during the course of the cool- ‘
bination of externally extended thermally inte
ing air through said space.
gral metal members in the path of the cooling air,
5. Temperature equalizing means for engine 65 a jacket having inlet and outlet openings and
cylinder barrels comprising a plurality of closely
enclosing the air stream, and means for equaliz
adjacent circumferential heat radiating ?ns ther
ing the temperature of the cylinder walls circum
mally united to the external surface of the bar
ferentially thereof, said means comprising a cir
rel, cowl members partially surrounding the bar
cumferentially increasing metal surface swept by
rel for con?ning the air ?ow to the inter-?n 70 the air between said inlet and outlet openings
spaces, and means to increase the mass velocity
said metal surface increasing in area toward said
of vthe air during its course through the inter
outlet opening, and said metal surface receiving
?n spaces, said ?ns gradually increasing in area
heat by conduction from said cylinder.
and said inter?n air spaces decreasing during the
/ 12. In an air cooled internal combustion engine
course of the cooling air through said space.
cylinder in which the cooling air ?ows trans
2,406,051
7
.
yersely across and around said cylinder, .thecom
bination of'externally extended thermally inte
gral metal members in the path of the cooling
air, va jacket having inlet and outlet openings and
enclosing the air stream, and means for equal
izing, the temperature of the cylinder walls cir
cumferentially thereof, said means comprising a
‘gradually and circumferentially increasing cross
sectionof metal in thedirecti-on of the outlet
~
8
entially increasing cross section of metal con
ducting-heat from the cylinder to the .air swept
surface.
_,
>
'
,_
'
,- 15. In an air cooled internal combustion .en
gine cylinder in which the cooling air ?owstrans
versely across and around said cylinder, the com
bination of externally extended thermally in-v
tegral metal members in the path of the‘ cooling
air, a jacket having inlet and outlet openings and
opening conducting l'i'eatfrornv the cylinder to 10 enclosing the air stream, and means for equaliz
the air-swept surface.
‘
.
c
,
\ ing the-temperature of the cylinder walls circum
l, 13. In an air cooled internal combustion engine
> ferentially thereof, means comprising a circum
cylinder in which the cooling air ?ows trans
versely across and around said cylinder, the com
ferentially increasing metal surface swept by the
air between said inlet and outlet openings, said
15 metal surface receiving heat by conduction from
bination of externally extended thermally in
tegral metal members in the path of the vcooling -
said cylinder, and a circumferentially increasing
air, a jacket having inlet and outlet openings
and enclosing the air stream, and means for
cross section of metal conducting-heat from the
cylinder to the air swept surface.
'
I
r
,
equalizing the temperature of the cylinder walls
16. In an air cooled internal combustion en-,
circumferentially thereof, said means comprising 20 gine cylinder in which the cooling air flows trans-.
acircumferentially decreasing air ?ow area be
versely across and around said cylinder, the com
tween said inlet and outlet openings, and a cir
bination of externally extended thermally inte
cumferentially increasing metal surface swept
gral metalmembersin the path of the cooling-air,
by the air between said inlet and outlet openings,
a jacket having inlet and outlet openings and en
said metal surfaces receiving heat by conduction 25 closing‘ the air stream, and means for equaliz
from the cylinder.
ing the temperature of the cylinder walls circum
, 14. In an air cooled internal combustion en-p
ferentially thereof, said means comprising a cir
gine cylinder in which the cooling air ‘?ows trans
‘ cumferentially ‘decreasing air flow arearbetween
versely across and around said cylinder, the com
bination of externally extended thermally in 30 said inlet and outlet openings, circumferentially
increasing metal surfaces swept by the air be
tegral metal members in the path of the ‘cooling
tween said inlet and outlet openings whereby said
air, a jacket having inlet and outlet openings and
, metal surfaces may receive heat from conduction
‘enclosing the air stream, and means for equaliz
from said cylinder, and a circumferentially in
ing the temperature of the cylinder walls circum- c
'ferentially thereof, said means comprising a cir 35 creasing cross section of metal conducting heat
from the cylinder to said air swept air surface.
cumferentially decreasing air flow area between
CHARLES‘ E. LUCKE.
said inlet and. outlet openings, and a circumfer
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