Sometime in the early part of March, Frank convinced Markham that he
could construct a new and practical engine, using only previously tried
mechanical principles.[18] Drawing up new plans for this engine, he took
them to Charles Marshall who began work on the patterns for the new
engine castings. After the patterns had been delivered to the foundry,
Frank left Springfield for a short vacation in Groton, Connecticut,
where he visited with his fiancée. On May 17, 1893, several weeks after
his return to Springfield, they were married.
The engine castings were undoubtedly received from the foundry prior to
Frank Duryea's marriage, and the work of machining and assembling the
parts went on through the spring and summer. This engine, still on the
carriage in the Museum of History and Technology, is cased with a water
jacket, and has bases on top to support the front and rear bearings of
the starting crankshaft, and a base with port on the upper right side
where the exhaust-valve housing was to be bolted. On the underside are
two flanges, forming a base for seating the engine on the axle. A
separate combustion chamber is cast and bolted to the head. Inside this
chamber are located the igniter parts of Frank's electric ignition
system. The fixed part, an insulated electrode, is screwed into the
right side of the chamber and is connected with the ignition switch
outside, to which one of the ignition wires is attached. A breaker arm
inside is pinned to a small shaft extending through the top of the
chamber. Around the breaker-arm shaft is a small coil spring (originally
a spiral spring, according to the letter of Charles Duryea shown in fig.
17), anchored below to a thin brass finger extending toward the right
side of the car, and above to a nut screwed tightly onto the shaft. This
nut is also the terminal for the other ignition wire. The action of the
spring keeps the breaker arm and the electrode in constant contact until
the push rod on the end of the piston strikes the arm and separates the
two parts. Breaking contact then produces the ignition spark. Since the
mechanism would spark at the end of both the exhaust and compression
strokes, the battery current is conserved by a contact strip, on the
underside of the larger exhaust-valve gear, by means of which the flow
of current is cut off during the greater part of the cycle.
On the left side of the combustion chamber is bolted the housing
containing the tiny intake valve. A comparatively weak spring seats this
valve in order that the suction created by the piston can easily pull it
open. Clamped onto the valve housing is the intake pipe, enclosing the
choke and carrying the carburetor on its forward side. The choke
consists of two discs which block the pipe, each with four holes at the
edges and one in the center. Turning one disc by means of a small handle
outside, so that the four outer holes cannot coincide with those in the
other disc, decreases the flow of air and causes all air to rush through
the center hole, where the tiny carburetor tube passes through. The
present carburetor was transferred over from the first engine. When
Frank later installed the engine on the carriage he noticed the close
proximity of the intake pipe to the open end of the muffler. Believing
that the fumes might choke the engine, he attached a long sheet-metal
tube to the intake pipe so that fresh air would be drawn in from a point
farther forward on the vehicle.
Moving to the right side of the engine brings the exhaust-valve assembly
into view. This valve is contained in a casting bolted over the exhaust
port in the side of the cylinder, and from the casting a pipe leads to
the muffler underneath. The valve is pushed open by a rod connected to a
crank which is pinned to the lower end of a shaft carrying an iron gear
on top. This gear is in mesh with a fiber gear, keyed to the upper end
of the crankshaft, with half the number of teeth. This ratio permits the
opening of the exhaust valve on every other revolution.
The crankshaft of the first engine was retained for the new engine, thus
giving the two engines the same stroke of 5-3/8 inches, but the bore was
increased slightly to 4-3/8 inches. With this larger bore and with the
engine speed increased to 500 rpm, Frank rated this engine at 4 hp.[19]
A heavier flywheel, with a governor resting in the upper recess, was
pressed onto the crankshaft. As the operator of the vehicle had no
control over the carburetor once he climbed into the seat, this governor
was necessary to maintain regular engine speed. Its function was to move
a slide on the exhaust-valve unit to prevent the valve from closing.
Thus the engine, with the suction broken, could not draw a charge on the
next revolution. During the recent restoration of this carriage it was
found that while most parts are still intact, nearly all of the
governor parts are missing. A description of them must therefore be
based on the recollections of Frank Duryea, along with certain evidences
seen on the engine.
[Illustration: FIGURE 19.--UNDER SIDE of exhaust valve mechanism showing
electrical contacts that give spark only on every other revolution.]
Just on top of the flywheel, and surrounding the crankshaft, rest two
rings, 3-7/8 inches in diameter. Into the opposing surfaces of these
rings are cut a series of small inclined planes, appertinent to each
other. On the outer circumference of the upper ring two pins pass
through a pair of lugs mounted in the flywheel, causing the ring to
rotate with the flywheel, yet permitting vertical movement. Underneath,
the other ring is allowed to turn slightly when, by means of two
connecting links, the arms of the governor push against them. These two
arms, each constructed like a right angle and pivoted at the apex, are
arranged directly opposite each other far out in the flywheel recess. As
a weight on one angle of the arm presses outward by centrifugal force
against a spring, the other angle presses inward against the connecting
link mentioned above. The turning of the lower set of inclined planes
against the fixed set above raises the upper ring and the fork resting
on it. The upward movement of this fork, which is a continuation of an
arm pivoted to a bracket midway between the crankshaft and the slide
carrying the exhaust valve stop, causes the other end of the arm to
drop, pulling the slide down with it. In this manner the closing of the
exhaust valve is blocked, preventing the intake of the next charge, and
therefore the engine misses one or more explosions until it slows to its
normal speed.
A starting shaft is mounted above the engine casting by a cast-iron
bracket on either end. The front end of the shaft has a bevel gear which
is held by a coil spring behind the front bracket, just out of contact
with a bevel gear pressed onto the upper end of the crankshaft. The
short rear portion of the shaft is a tube which slides over the main
shaft. Fitting the removable handcrank to the squared end of the hollow
shaft and turning the crank clockwise, will advance the forward section
of shaft through the medium of a pair of inclined collars. With the
bevel gears now engaged the engine may be cranked. When ignition begins,
the inclined collars slide back down each other's surfaces, the shaft is
again shortened, and its bevel gear springs free of the one on the
crankshaft.
[Illustration: FIGURE 20.--PISTON AND CONNECTING ROD of second engine.
Screw on rod is where oil is poured into connecting rod to lubricate wrist
pin and crankshaft.]
While Frank worked on his engine, he realized that certain parts of the
old running gear would need to be altered or replaced. In view of the
heavier and more powerful engine, he felt the old wheels, probably
having compressed band hubs, were inadequate. He procured a set of new,
heavier wheels[20] with Warner-type, cast-iron reinforced hubs. The
angle iron frame, apparently sturdy enough to carry the added weight,
was retained, but it was decided to install a heavier rear axle.[21] The
front axle assembly was at first allowed to remain unchanged, as was the
steering apparatus. A short time later when the engine and friction
transmission were bolted in place on the running gear, Frank saw that
the rigidity of the framework had an undesirable effect. When the
vehicle passed over any unevenness in the shop floor, the framework was
distorted and caused the jackshaft bearings to bind tightly enough on
the shaft to prevent its being turned by hand. In order to provide the
3-point suspension necessary to eliminate this distortion, Frank
attached the forward parts of the framework to an extra wooden spring
bar, installing between this bar and the front axle a vertical fifth
wheel of the type ordinarily used in a horizontal position in any light
carriage.
Frank next calculated that with the faster running engine the speed of
the vehicle would be about 15 miles an hour, too much for the heavily
loaded wheels. As he intended to make use of the original transmission,
he decided to decrease the speed by increasing the size of the friction
drum. He accomplished this by sliding a heavy fiber tube over the
original drum, bringing its diameter to approximately 14 inches. The
original shipper fork carriage was improved by separating the original
bearings to a greater distance, and eliminating one of the two bearings
on one end. This permitted a smooth and free operation of the small
sliding carriage.
In August 1893, possibly as a result of indoor experiments, Frank
discovered that the chains running from the small 5-tooth[22] jackshaft
sprockets to the large, bronze, wheel sprockets were tight at some times
and loose at others. This caused considerable unnecessary noise. The
difficulty apparently was the result of the sprockets being cast and not
machined. The patternmaker had said he believed he could make the
pattern accurately enough so that no machining of the castings would be
necessary. Nice castings were produced, but "these sprockets were the
reason why an unusual construction was put on the crankshaft [meaning
jackshaft]," explained Frank Duryea during an interview at the National
Museum on November 9, 1956. Elaborating further, in reply to the queries
of E. A. Battison, of the Museum's division of engineering, Duryea told
of the problem and the solution when he explained that the sprockets had
places where the shrinkage was not even. The hot metal, contracting as
it cooled, did not seem to contract uniformly, creating slightly unequal
distances between teeth. This resulted in the chain hanging quite loose
in some places and in others the tightness prevented adjustment. He
contacted Will Russell, foreman of the Russell shop, where the
automobile was made, and Russell showed him a device, built by George
Warwick, who had made the Warwick bicycle. It was an internal-cut gear,
according to Duryea's description, with sprocket teeth on its periphery.
With sprockets outside and normal teeth inside, the wheels were about 6
inches in diameter, externally.
These little internal-gear sprockets were hung on double-shrouded
pinions secured to each end of the jackshaft. A solid disc or housing
fitted against both ends of the pinion to prevent the internal gear
from working off sideways. Duryea explained the function of these
unique little parts: "as soon as tension came on that ring gear that we
talked about, it not only tightened the chain hanging on this sprocket
on the upper side, but it tightened it on both sides. [The sprocket]
rocks right out: both sides of the chain are tight."
This feature is one rarely encountered elsewhere, and Duryea, later in
the interview said, "To tell you the truth, I think I was just a little
bit ashamed about the thing, because I had to pull it off. I didn't like
the looks of it after I got it on."
Two small tanks, each with a capacity of approximately two gallons, were
mounted over the engine in the positions they still occupy, the one on
the left for gasoline,[23] the other for water. The small fitting under
the gasoline tank has a thumbscrew shutoff and a glass-sight feed tube,
leading to the carburetor. The water tank, an inch longer than the
gasoline tank, communicates with the water jacket of the engine through
two pieces of half-inch pipe, entering the jacket from above and below.
The overflow tank, holding just over a gallon, is suspended between the
rear axle and the flywheel.
A number of mufflers were constructed for the engine.[24] The first
experimental one was built of wood, being a box 6 × 6 × 15 inches with a
hole for the exhaust pipe in one end and a series of small holes in the
opposite end. Inside, Frank arranged metal plates which were somewhat
shorter than the depth of the box. Every other one was attached to the
bottom of the box; the intermediate plates were fastened to the top.
This contrivance muffled the sound considerably, but, as might be
expected, soon began to smoke. There can be little doubt that it was
replaced before any of the outdoor trials began. Another type consisted
of a cylindrical metal shell, perhaps six inches in diameter and ten or
twelve inches long. Here a series of perforated baffle plates were
inserted, with alternating solid plates having parts of their external
edges cut away. Two bolts running the length of the muffler held on the
cast-iron heads in a manner quite similar to the Model-T Ford mufflers
of later years. Though partially satisfactory, Frank, in a November 6,
1957, interview, complained that it made a metallic sound. Perhaps this
was the muffler he used from September to November 1893.
[Illustration: FIGURE 21.--ILLUSTRATION OF THE NO. 2 SAMSON BATTERY used
by the Duryeas in their vehicle. (Smithsonian photo 46858.)]
On August 28 Frank wrote to Charles saying the carriage was almost ready
for the road and that he hoped to take it out for a test on the coming
Saturday, "off somewhere so no one will see us...."[25] There is no
evidence showing whether the amount of remaining work permitted the
proposed trial on September 2. The body was finally replaced on the
running gear, at which time it was found necessary to raise the seat
cushion several inches by the insertion of a framework made of old
crating boards. This allowed sufficient room between the seat and the
frame to suspend the batteries and coil. Six no. 2 Samson batteries were
contained in this space, three on each side, in rows parallel to the
side of the vehicle. The Samson battery consisted of a glass jar
containing a solution of ammonia salts and water, with a carbon rod in
the center, housing a zinc rod. It is difficult to understand why they
used Samson batteries rather than dry cells; perhaps they were concerned
with the mounting cost of the machine and were making use of parts
already on hand.[26] A coil, possibly from an old gaslight igniter
system, accompanied the Samson batteries under the seat. This original
coil is now missing.
The iron dash frame, previously recovered and provided with a rain apron
to be pulled up over the knees in the event a heavy rain blew in under
the carriage top, was bolted back in place. Frank and Mr. Markham gave
the carriage a quick painting; later Frank admitted, "the machine never
had a good job of painting."[27] Before the motor wagon actually got
onto the road, a reporter on the _Springfield Evening Union_ got some
statistics on it and an item appeared on September 16, giving the first
public notice of the machine.
[Illustration: NO USE FOR HORSES.
Springfield Mechanics Devise a New Mode of Travel.
Ingenious Wagon Now Being Made in This City for Which the Makers Claim
Great Things.
A new motor carriage, which, if the preliminary tests prove successful
as is expected, will revolutionize the mode of travel on highways, and
do away with the horse as a means of transportation, is being made in
this city. It is quite probable that within a short time one may be able
to see an ordinary carriage in almost every respect, running along the
streets or climbing country hills without visible means of propulsion.
The carriage is being built by J. F. Duryea, the designer and B. F.
Markham, who have been at work on it for over a year. The vehicle was
designed by C. E. Duryea, a bicycle manufacturer of Peoria, Ill., and he
communicated his scheme to his brother, who is a practical machanic in
this city.
The propelling power is furnished by a two-horse power gasoline motor
situated near the rear axle and which, when started, runs continuously
to the end of the trip, notwithstanding the number of times the carriage
may be stopped. The speed of the motor is uniform, being about 500
revolutions a minute, and is so arranged that it gives a multiplied
power for climbing hills and the lower the rate of speed the greater
power is furnished by the motor. The slowest that the carriage can be
driven is three miles an hour and the speed can be increased to fourteen
or fifteen miles an hour. The power is transferred from the driving
wheel of the motor, which runs horizontally with the main shaft by an
endless friction belt running on a drum wheel. The belt is controlled by
a lever within easy reach of the driver and is shifted along the drum
wheel to increase or decrease the speed. The driving wheel is about
twenty inches in diameter, having in its center a depression to which
the belt is shifted to stop the carriage.
The carriage can be reversed by shifting the belt from the end of the
drum, which gives the forward motion to the opposite side beyond the
depression in the driving wheel. The power which has been transferred to
the driving shaft from the motor is in turn transferred to the two rear
wheels of the carriage by a combination gear and sprockets. An endless
chain connects the sprockets on the carriage wheels to the sprocket
wheels on the driving shaft. All of the motive power is located under
the body of an ordinary phaeton, the hight of which is not increased by
the machinery. The motor is started by a crank which is easily applied
to a shaft in the rear of the carriage and the gasoline is ignited in
the cylinder by electricity. An automatic device stops the flow of
gasoline into the cylinder when the motor ceases running. The gasoline
is carried in tanks, which hold about two gallons, and which will run
the carriage for about eight hours. The wagon is guided by a bicycle
bar, and the speed is also controlled by this bar.
The method employed in this is as follows: To start the carriage press
the lever down; to reverse it throw the lever up and to guide the wagon
turn the lever either to the right or left. The front axle instead of
turning horizontally plays up and down, in order that the machinery may
be on a level with the rear wheels, while the front wheels are set on
the axle by a pivotal joint and are connected with the guiding lever by
bars with ball bearings. The carriage complete weighs about 220 pounds,
and the essential features are already covered by patents while others
are pending.
It is estimated that the carriages can be sold for about $400, and a
stock company will probably be formed to manufacture them.