New-York tribune., 1908-01-07
New TESTS FOR AUTOS.
MEASURE SPEED OF CARS.
First Trial of Dynamometer By
automobile Club of america.


the club dynamometer. machine which Will de-
terrrne instantly the speed in miles an hour ana
feet a second. the drawbar pull or tractVe ehort'
the horsepower. the grade climbing ability and the
power the brakes OF automobile which is
placed upon IT.
There is no other machine in the world which
will do the work of this one and probably other
institution could afford to construct and operate
similar machine. 1t is of great Importance TO own
and purchasers of and Will be welcome
among manufacturers. because il will enable them
TO determine precisely what their can dc and
viii give them standard to which they can refer
with confidence
The first made yesterday at the club
house. and among those who witnessed 1t were
Colgate Hoyt. president Of the Automobile Club OF
America; Dave Hennen Morris and A. r. Shattuck.
former presidents; S. NJ Butler, secretary; Robert
Lee Morrell General George Moore Smith, Russell
Field. secretary of the Long Island Automobile
Club: DIR. Schuyler Skaats Wheeler and Joe Tracy
William X. Vanderbilt. jr.'s. so-horsepower racing
the first tested On the second gear
with 30 degree grade. it developed 90 horsepower
for a speed of twenty-one miles hour and
showed drawbar pull or tractive effort OF $50
pounds. On the fourth gear and Q degree grade
travelled seventy miles hour. developing
80 horsepower and a drawback pull of 200 pounds
The dynamometer. besides being the most COM
rete apparatus built for testing automobiles.
makes il unnecessary get special permission 70
speed machines in making running test Will elm
mate all danger of road accidents during tests and
give the results quickly and accurately than in
any other way. Il is of the greatest value to the
intending purchaser of automobile and TO the
manufacturer who wishes TO close sale 1t is pro-
vided with electric fan device for catching the
exhaust from the running automobile. in order thar
the air n the may be kept clear of smoke and
obnoxious fumes.
The word -'dynamometer' is usually applied a
simple apparatus. either spring balance for weigh
ing the draw-bar pull required draw a carriage
or railroad at given speed. or power absorb
ing device for consuming the power given off by
engine under trial. There also numerous other
forms. To obtain results is always necessary
make calculations from the readings observed The
apparatus at the club is machine upon which
automobile of any kind may be placed and operated
and the result read in speed, pull and horse
power 1t is therefore not only dynamometer in
the usual sense. but a calculator Of the readings
obtained by dynamometer.
The club dynamometer is a moving track upon
(which be fully tried while remaining
stationary and under observation. In 1894 DR..
Schuyler Skaats Wheeler first vice-presdent Of the
Automobile Cub. requested by the club to in
vent, design and build machine for determining
accurately the performance of cars of all kinds.
The present machine is therefore the result of sew
ersi years attention this problem the part OF
Dr Wheeler.
1t is an assemblage of power absorbing and meas
uring instruments. and large power chart with
tomatically operated pointers 1t carries the prob
lem of power measurement integration and
matte recording of the final results much further
than has hitherto been attempted II absorbs and
measures the power that a glance the speed.
IractIFe EFFORT and horsepower can be clearly
and read at each instant The measurements show
the power delivered at the ground by the wheels of
the automobile This includes every element in the
operation of the automobile. and, therefore shows
the net power that is available for driving the
Instead of travelling along a road, the
is held stationary by cables upon the floor with its
driving wheels resting upon two large drums which
reach up through the floor. and which the
the automobile causes revolre. The revolution Of
the drums is resisted by a huge pendulum hanging
below the floor and attached the drum shaft not
rigidy, but through device furnishing degree of
friction which be varied.
The pendulum. in consequence. swings out from
the vertical distance exactly proportional TO the
pull exerted by the upon the drums The
amount Of this pull. -tractive effort is indicat-
ed by pointer attached the pendulum and
reaching above the floor. This weighing apparatus
pendulum has been tested and certified correct
by the Fairbanks Company The indications given
by the pendulum transferred 10 a ruler travel
ling the face OF a large chart by a wire
cable moved by small motor. in such manner that
with each varying position of the pendulum pointer
the cable is moved to correspond TO its position
The difficult operation of measuring ac-
curately the speed Of the by moving another
ruler vertically across the large chart is accom-
plished by special apparatus of novelty.
is revolved by electric motor at abso-
lutely constant speed To verify this speed a bell
attached to the shaft rings each 100 revou-
tons intervals of 80 seconds A wheel or
roller driven by the automobile, and therefore
voiVi1g slowly fast to correspond, rolls upon
the surface of the and is pulled by an inde-
pendent motor back and forth between the small
and large ends OF the until IL finds the point
where ii does not slip because that portion Of
|. the cone presents the same speed the roller
This longitudinal adjustment of the roller trans
j mtted by wire cable the speed ruler on the
chart, and the power required for moving the ruler
is thus made independent of the automobile. In
other words OF the power of the automobile
is used in operating the indicators the chart
The method OF speed measurement employed
based upon element running at a constant
speed like clock. that be verified. insures
great accuracy. The roller, driven by the car IL
running at sixty miles hour. must be drawn
a position the large end of the cone in
order run with the Whereas if the car
drives the roller only five miles hour, it
must be drawn TO position the small end
of the cone. A system of electric contacts is ar
ranged with a motor TO shift the roller automati-
cally until it finds the point where it will roll on
the cone without slipping
The speed and power rulers are thus moved across
the char automatically 10 correspond with the
speed and the tractive effort or pull that the
dynamometer shows $ making. On the
board is painted the horsepower corresponding to
each different speed and pull that the result at
each moment can be read at glance and without
calculations
All Of the measuring apparatus is made reversi-
BILE so that when running backward the perform
ance of the car may be measured
AS secondary apparatus. grade meter is pro-
video. operated by pendulum indicator of the
oynamometer. To the grade meter the clamp
IS upon the sliding scale point represent
ing the weight of the car The moving lever then
assumes each moment the angle of inclinati ton
Of the grade the would climb Gf there were no
wind resistance. slipping. etc). with the effort that