loud knock, due, undoubtedly, to the movement of 

 the free piston. Had the engine operated con- 

 tinuously, it is likely that the action of the free piston 

 would have shortly wrecked the engine. Further 

 efforts appeared unwarranted until alterations could 

 be made. 



The two pistons were first pinned together into a 

 single unit which was probably ringless, since it is 

 believed the walls of the outer piston were too thin 

 to admit rings. Because the piston no longer struck 

 the exhaust valve, a short rod had to be screwed into 

 the pistonhead; this pushed the valve shut at the 

 completion of the exhaust stroke. The remaining 

 problem, the opening of the exhaust valve, was solved 

 by screwing a device to the side of the cylinder which 

 operated from the sidewise motion of the connecting 

 rod. This device shifted a small spacer between the 

 piston and the striker arm of the exhaust-valve rod, 

 permitting the piston to push open the exhaust valve. 

 On alternating strokes the spacer shifted back out of 

 the cylinder; therefore, no contact was made between 

 piston and striker arm. Sometime in February 

 1893, the altered engine was successfully started. 



At last the transmission could be tested. Will 

 Russell had come upstairs to watch the trial, and 

 according to a statement by him, given April 30, 

 1926, Frank, standing to the right of the engine and 

 behind the rear axle, reached forward and with the 

 combination tiller-belt-shifter, moved the belt into 

 driving position. The carriage started forward, but 

 as it approached the wall of the building Frank dis- 

 covered that he could not get the belt back into the 

 neutral position. In desperation, he grasped the rear 

 axle with both hands and was dragged a short distance, 

 attempting to stop the machine, before it struck 

 the wall. He had, however, sufficiently retarded it 

 so that no damage was clone. 



This short trial demonstrated some of the weaknesses 

 in the friction transmission. Since the speed of the 

 surface of the flywheel, in feet per second, increased 

 in proportion to the distance of the point of contact 

 from the center, the outer edge of the belt attempted 

 to run faster than the inner edge. This conflict of 

 forces not only put an undue load on the motor 

 causing a great loss of power, but it also created a 

 tendency for the belt to work towards the outer edge of 

 the flywheel. Conversely, when the operator desired 

 to return the belt to neutral, it strongly resisted any 

 efforts to slide it toward the center of the wheel, as 

 Frank had learned from the wall-bumping incident. 

 Furthermore, the rubber belt on the friction drum had 



Figure i8. — Ignition chamber, switch, and breaker 

 contacts of the present Duryea engine. 



worn so badly that it had to be replaced at least once 

 during the brief experiments. 



At this point, Frank and Markham felt that the car- 

 riage was anything but satisfactory. While they 

 were trying to decide what steps should be taken next, 

 Frank added one last improvement to the engine. 

 Fearing that the uncooled cylinder might suffer 

 damage from the excessive heat, he constructed a 

 copper water jacket in two halves, drew them together 

 around the cylinder with clamping rings and soldered 

 the seams. Asbestos packing sealed the end joints 

 where the jacket contacted the cylinder. Thinking 

 back, Frank does not recall that he ever used a water 

 tank with this engine, though he does remember adding 

 water through the upper jacket opening. The 

 engine was run only for a few brief periods following 

 this addition. 



Obviously this collection of patchwork could not 

 fulfill their needs for an engine. First, it would be 

 next to impossible to start if the body was placed on 

 the running gear, as the flywheel then would be 

 practically inaccessible. The absence of rings on the 

 piston caused a further loss of power to the already 

 overloaded engine. The flywheel was too light. The 

 absence of any form of governor left the operator with 

 no control over the engine speed. Ignition was poor, 

 partly owing to the hot-tube arrangement, and partly 

 to the excessive distance between the engine and the 

 carburetor. Frank wrote his brother Charles on 

 February 6 17 that in his opinion the mixing chamber 

 was so far from the engine that the gasoline could not 

 be drawn into the cylinder as liquid, and it was too 

 cold to vaporize and go in as gas. Thus he had 

 difficulty in getting the engine started. When it 

 did start the explosions were unmuffled. Less im- 

 portant to him than these defects, however, was the 

 awkward and unsightly wooden engine mount. 



' Copy of letter in Museum files. 



PAPER 34: THE 1893 DURYEA AUTOMOBILE 



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