The Washington times., 1915-03-27
DUPLEX TRUCK DOES
"STUNTS" IN TESTS
Demonstrations Are Given With
1t Before Committee OF Ma
rine Corps Officers.
By WILLIAM P. ROSE.

A two-ton Duplex truck has been do
ing stunts this week before com
mittee of officers from the marine corps
composed of Col. T.. X. Cole, Major II.
III. Dunlap, Major II. l.. Roosevelt, and
Capt. r. Q. Underwood.
The truck Is equipped with a dark
blue body. and Is four wheel drive,
four wheel steer and four wheel brake
manufactured by the Duplex Power
Car Company. of Charlotte, Mich This
company is represented in Washington
and before the Government by f. II.
Parks, located in the Munsey Building
The DUPLEX Power Car Company was
originally organized to build "a four
wheel driven motor truck, and for six
years 1t has specialized in this type,
in which the axle jackshafts driving
spur pfnions mesh with internal ring
gears enclosed in drums on the rear
wheels. The fundamental principles
that prompted the building of the first
truck were primarily to have as small q
power plant as was practical because or
the need OF fuel economy; next to nave
transmission system that would have
as high a ratio Of efficiency as could be
obtained from the fuel used; and still
further, to minimize the expense OF
tires by equal wear upon all four.
Loss of Power eRduced.
In experiments on level surfaces,
tractive effort ought to be equal,
whether by two or four yheels. but
when traction Is lessened by wet pave
ments, mud, snow, sand, or loose soil,
withb but one or two wheels driving,
half the useful power available is lost
With four wheels driving the loss OF
power can be greatly reduced, because
with four points Of contact with the
highway there is less probability OF
reduction of traction. In experimental
work and service the utility of the Du.
plex drive was found to be so superior
to any other system that tests Of ex.
treme character were made in condi.
ttons where the practical use of motor
vehicles would seemingly be impossible
Possibly 1t was this claim on the part
Of the Duplex Company that caused the
Marine Corps to send the truck through
the racking tests Of the past few days
Many WITNESS eTst.
The first demonstration Of power hap.
pened in lower Potomac Park, just be-
low the Southern Railway bridge II
the field on the left Of the road. Be
sides the representatives of the Duple,
Company. F. r. Parks and Chief Engi
neer H. NJ. Leonard. and the Marine
Corps Board, about a hundred Wash
ington automobile men witnessed the
test.
The surface of the field here Is moth
ing but shell about sin inches thick
which Is undermined with bottomless
soft mud and water. The truck wa:
loaded with about two tons, including
the weight Of the cumbersome body
with which the chassis was equipped
because of specifications, and the
wheels were shod with four-inch soliC
Firestone tires.
Naturally, the truck had hardly gotten
into the field before all four wheels went
nearly to the hub, with the two rear
wheels hopelessly without traction. But
When the load was taken out of the
body and the forward rims of the
rear wheels given a slight traction by
shoveling away the earth above the
hubs. the truck came out easily under
It's own power.
Field Running Demonstrated.
Later in the day tests were conducted
at Fort Myer. when the truck wen
through ditch less than five feet wide
and nearly four feet deep carrying i'm
pedimenta of the artillery corps. Tielc
running with the artillery, which in
Volved hauling. was also demonstrated
On Friday an endurance run was
made to Manassas, under the super
vision Of the marine corps. All the testl
were generally satisfactory to Mr.
Parks.
A jeffrey quad" was present at al
OF the tests under the supervision OF
Captain Cranston. of the Combs Howard
Company. Its performances were high
ly creditable, but to be quite accurate
1t must be reported that the jeffrey wa.
equipped with wider Swinehart cellula,