Omaha daily bee. (Omaha [Neb.]) 187?-1922, 1919-06-01
HOLMES CAR HAS.
THREE VALVES TO
EACH CYLINDER
Latest Design of Air-Coo|ed
Car Includes 10 Overhead
Valves; Designed by Ar
thur Holmes.

| A new development in automo-
bile motors of the overhead valves
type is presented in the Holmes inn
proved air-cooled motor in the pres
ent series of production.
The use of Is valves comes as the
result OF work done by Arthur
Holmes, designer of the Holmes
car, as consulting engineer on aero
plane motors of the air-cooled type
used in combat planes.
There are three valves to each
cylinder, all in the head, the ex-
haust valves being dual in con-
struction, actuated from one rocker
arm which is operated from the cam
shaft by the usual type of valve
litter rod construction.
Three purposes are served by the
Is valves design in the Holmes
motor. The first is the development
of greater power through a better
use of the fuel, accomplished by a
more rapid clearing of the dead gases
from the cylinders; second, more
| flexible motor due to the more COM
plete ignition of the fuel; third, a
quieter running motor than has
hitherto been associated with over
head valve construction.
In general details of construction
the Holmes improved air-cooled
motor follows the lines developed
by Mr.. Holmes during the lo years
he has been the leading engineer
in the country on air-cooled motors
for automobiles.
Cylinders Cast Individually.
The six cylinders are cast in
dividually. Cylinder dimensions are:
bore, 81 inches; stroke, AZ inches,
giving an N. A. c. c. rating of
2o.4 horsepower. Crank case and
oil pan are aluminium. Each cylin-
der has 90 radial cooling fans mould
ed into the outer cylinder walls.
The radial fins give a total cooling
area of approximately 800 square
inches. Over these fins a steady
current of air is drawn by the Sue
ton fan in the flywheel Of the
motor
The direction of the air currents
over the cylinders is controlled by
the hood of the motor, metal deck
located just below the cylinder
heads and extending the foil length
and width of the hood, metal side
plates which close the upper COM
partnent formed by the deck from
the lower compartment, and the en-
CINE boot
The upper compartment is prac-
tically air tight in its relation to
the lower compartment, being closed
by a metal plate at the front end
of the motor and by the dash at
the rear end.
Cylinders Ale Enclosed.
The cylinders are further enclosed
by metal plate on either side, ex-
tending the full length of the fins
and shaped in semicircles partially
around each cylinder These cylin-
der side walls are held in place by
the metal deck forming the division
between the upper and lower COM
partments.
AS the fywheel starts to revolve
with the turning over of the motor,
the suction fan sets up a partial
vacuum in the lower compartments.
To fill this vacuum air is drawn in
through the grilled opening at the
front of the hood, into the upper
compartment and down around the
radial fins. Thence the air, which
has cooled the cylinders, passes out
through the blades of the fywheel.
The advantages of this type of
cooling are: First, controlled
amount of cooling medium at any
time; second, the application of the
cooling medium to the hottest part
of the cylinders, the cylinder heads,
when the medium is coolest-the
reverse of water cooling; third, a
greater margin of cooling efficiency
in the cooling medium in relation
to outside temperature; fourth, the
maintaining of a greater degree of
heat efficiency in the cylinders than
is possible with water cooling; fifth,
less jacket loss, and sixth, an en-
tire independence of outside tenn
perature conditions as affecting the
cooling medium.