close

Вход

Забыли?

вход по аккаунту

?

Патент USA US2119221

код для вставки
‘May 31, 1938'.
'
K. CAMPBELL
v
2,119,221 ~
ENGINEKCOWLING
Filed May 15, 1957
INVENTOR. '
irrmwwwmzzz
2,119,221
Patented May 31, 1938
UNITED STATES PATENT OFFICE
' 2,119,221
ENGINE COWLING
_ Kenneth Campbell, Radburn, N. J., assignor to
Wright Aeronautical Corporation, a corpora
tion of New York
Application May 15, 1937, Serial No. 142,760
4 Claims. (Cl. 123-171)
built with the opening diameter approximately
This invention comprises improvements in an
nular anti-drag cowling adapted for use in con’
nection with radial cylinder air-cooled engines.
In current types of aircraft, radial cylinder
5 engines are mounted at the forward end of a
streamlined body or nacelle structure, and for
the purpose of reducing engine drag, and also
for improving engine coo-ling, the engine is em
braced by an annular cowling member provided
10 with a forward air entrance opening and an air
exit opening rearward of the engine and be
tween the cowling and body. In normal practice,
the air entrance opening is circular and con
centric with the engine, and it has been found
that under conditions of climb, where the engine
axis is upwardly tilted with respect to the rela
tive airstream, the ' cooling air entering the
cowling has a tendency to recirculate and spill
over the leading edge of the cowling to the detri
20‘ ment of effective engine cooling. It is an object
of this invention to provide a very simple cor
rection for the above indicated difficulty. It is
a further object of the invention to provide in
an engine embracing annular cowling, an air
25
entrance opening of particular form whereby
recirculation and spillage of air under high angle
of attack conditions is minimized.
Further objects will be apparent from a read
ing of the subjoined speci?cation and claims,
30 and from an examination of the accompanying
‘ drawing, in which similar numbers indicate sim
ilar or like parts, and in which:
'
Fig. 1 is a front elevation of an annular cowling
element embodying one form of the invention;
Fig. 2 is an axial section, through the cowling,
35
showing its application to an aircraft power
plant, and
'
Fig. 3 is a front elevation of an alternative
form of the invention.
,
Fig. 2 shows the general organization of an
annular engine embracing cowling Ill, suitably
attached to a radial cylinder engine ll mounted,
by structure ‘II, to a body l3. The engine car
rles at its forward end a propeller 14. The
45 cowling comprises a main body portion l5 hav
ing a trailing edge I6 radially spaced from the
body l3 to provide an annular air exit opening.
The body l5 extends forwardly and blends into
an inwardly curved leading edge portion l1 open
'50
at the front to provide an air entrance opening
l8. Normally, such an opening 18 is circular and
concentricwith the engine and tests have indi
cated that the diameter of this opening should
be 65% to 80% of the engine diameter for good
55 drag reduction. Some installations have been
85% of engine diameter in the interest of en
training a greater amount of cooling air within,
the cowling. Such cowling installations are gen
erally satisfactory in service, but it has been
found that under steep climb conditions, where
the engine axis is upwardly tilted with respect to
the relative airstream, the top cylinders of the
engine ‘tend to run hot, indicating a loss of cool
ing air within the upper part of the cowling.
This phenomenon is attributed to a spillage of
cooling air from the top part of the air entrance
opening. To correct this situation, I provide a
ba?ie or restriction l9 blanking off the top part
of the air entrance opening I8, which, in Fig. 1,
is shown as ‘a segment integral with the leading
edge portion ll of the cowling. In tests, this
baffle l9 has proved effective in minimizing loss
of cooling air from the top of the cowling, and
has been found to have no adverse effect under
low angle of attack, high speed ?ight conditions.
Expressing the conformation of the cowl air en
trance opening in another way, said opening
comprises a segment of a circle whose are of
embracement is of the order of 270°, said are
being symmetrical with respect to the plane of
symmetry of the aircraft.
An alternative form of the invention is shown
in Fig. 3, wherein the cowl air entrance opening
I8’ is in the form of a circle which is eccentric 30
to the main part of the cowling and eccentric
to the engine axis. In this instance, the center
for the air entrance opening I8’ is displaced
directly below the engine axis whereby the cowl
leading edge portion l'l' extends inwardly from _
the body‘ portion IS’ a greater distance at the
top of the cowling than at the bottom thereof.
It is believed that such an ececntric air entrance
opening would have substantially the same ef
fect in reducing spillage of cooling air as the
embodiment of Fig. 1.
In the application of either embodiment of the
invention, the net area of the air entrance open
ing may readily be arranged to Provide for the
entrainment of adequate cooling air under all 45
ordinary ?ight conditions.
'
‘ ‘
While I have described my invention in de
tail in its present preferred embodiment, it will
be obvious to those skilled in the art, after un
derstanding my invention, that various changes 50
and modi?cations may be made therein without
departing from the spirit or scope thereof. I aim
in the appended claims to cover all such mod
iflcations and changes.
I claim as my invention:
2
2,119,221
1. An annular anti-drag cowling for embrace
- ment of a static air-cooled engine comprising a
concentric iore-and-aft body portion, a con
centric inturned leading edge portion de?ning an
air entrance opening, and a segment portion
covering the upper annular air entrance opening,
whereby spillage of entering air is suppressed
when the cowl axis is inclined to the direction of
the attacking airstream, said cowling having an
10 exit opening through which air entrained within
the entrance opening may issue.
2. An annular anti-drag cowling for embrace
ment of a static air-cooled engine comprising an
inturned leading edge portion formed to de?ne a
forward air entrance opening, said opening be
ing of substantially circular outline, the circle
thereof being eccentric to and having its center
below, the cowling axis, whereby spillage of en
tering air is suppressed when the cowl axis is
20 inclined to the direction of the attacking air
stream, said cowling having an exit opening
through which air entrained within the entrance
opening may issue.
3. In an aircraft power plant, a static radial
cylinder engine, an annular cowling embracing
the engine cylinders having a leading edge de
?ning an air entrance opening ahead of the
engine for the reception of cooling air, said cowl
ing being subject to spillage of air toward the
top of its leading edge when the cowl axis is
inclined upwardly relative to the attacking air
stream, and a ba?ie across the uppermost seg
ment of said opening for preventing said spillage,
said cowling having an exit opening through
which air entrained within the entrance open
ing may issue.
10
4. In aircraft an annular anti-drag cowling
for embracement of an engine having a propeller
shaft extending forwardly of and substantially
concentric with the cowling, an inturned leading
edge for said cowling de?ning a substantially 15
central air entrance opening ahead of said en
gine including masking means forming an in
ward continuation of the uppermost part of said
leading edge to restrict the effective area of the
uppermost part of said air entrance opening,
whereby spillage of air from within the cowling
is suppressed during high angle of attack at
titudes of the aircraft, said cowling having an
exit opening through which air entrained with
in the entrance opening may issue.
KENNETH CAMPBELL.
Документ
Категория
Без категории
Просмотров
0
Размер файла
250 Кб
Теги
1/--страниц
Пожаловаться на содержимое документа