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Figure 14. — A portion of the Russell shop 

 records showing charges made against Charles 

 Duryea during 1 893-1 894. 



Patterns for the castings were fabricated, most of them 

 by Charles Marshall on Taylor Street, 12 and castings 

 were poured. The body or main casting of the engine 

 resembled a length of cast-iron pipe: it had no bosses 

 or lugs cast on, nor any water jacket, for they thought 

 the engine would be kept cool merely by being placed 

 in the open air. The front end of the engine was 

 secured to the vehicle by four bolts which passed 

 through the halves of the bearings and onto four 

 projections on the open end of the engine. As the 

 crankshaft of this engine was retained in constructing; 



the present engine, it is logical to assume that the 

 bearings were the same also. The head was cast as 

 a thick disc, with both intake and exhaust valves 

 located therein, and was bolted onto the flanged head 

 end of the engine. 



Inside the cylinder was the strange arrangement 

 previously suggested by C. E. Hawley. To the con- 

 necting rod was attached a rather ordinary ringed 

 piston, over which was fitted a free, ringless piston, 

 machined to fit closely the cylinder bore. This 

 floating piston could move freely a distance equal to 

 the compression space. The intention was that on 

 the intake stroke, suction would open the intake 

 valve, which had no positive opening arrangement, 

 and draw in the mixture which then was compressed 

 as in a regular Otto engine. Fired by the hot-tube 

 ignition system, the force of the explosion would 

 drive both pistons down, forcing the outer one tight 

 against the head of the smaller one, and at the end 

 of the stroke the longer wall of the outer piston 

 would strike an arm projecting into the cylinder 

 near the open end, moving forward the exhaust 

 valve rod to which the arm was attached, thus 

 pushing open the valve in the head. 13 On the 

 exhaust stroke the unrestrained outer piston moved 

 all the way to the head, expelling all of the products 

 of combustion and pushing the exhaust valve shut 

 again. With a bore of four inches or less, this engine, 

 Charles believed, should develop about three 

 horsepower and run at a speed between 350 to 400 

 revolutions per minute. 11 



As no ignition system had yet been provided, they 

 prepared a 4%-inch length of one-quarter inch iron 

 pipe, closed at one end, and screwed the open end 

 into the head. Heating this tube with an alcohol 

 burner would cause ignition of the mixture when a 

 portion of it was forced into the heated tube to- 

 ward the end of the compression stroke. No attempt 

 was made at this time to use the electrical make- 

 and-break circuit used in their second engine, as 

 the free piston would have wrecked the igniter parts 

 on the exhaust stroke, and the push rod located on 

 the end of the piston would have prevented the 

 piston from closing the exhaust valve. 



After keying the flywheel to the lower end of the 

 crankshaft, Charles and Frank decided to make an 



12 Recorded interview with Frank Duryea in U.S. National 

 Museum, November 6, 1957. 



13 Letter from Frank Duryea to David Beecroft, November 15, 

 1924; copy in Museum files. 



11 Letter from Charles Duryea to C. W. Mitman, March 21, 

 1922; copy in Museum files. 



PAPER 34: THE 1893 DURYEA AUTOMOBILE 



11 



