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 accom- 

 plished 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 ten- 

 sion 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 approxi- 

 mately 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. 21 The first experimental one was built ot 

 wood, being a box 6x6x15 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 consider- 

 ably, 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 twehe 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 



22 Letter from Charles Duryea to F. A. Taylor, December 5, 

 1936, says he "thought" they had five teeth. Copy in Museum 

 files. 



23 Frank later wrote his brother, January 1894, that he fixed 

 the tank so it would not draw sediment from the bottom. 

 Copy of letter in Museum files. 



24 The number of mufflers Frank Duryea constructed is not 

 known. He wrote Charles, December 22, 1893, that he "will 

 trv a new muffler also." 



li 



BULLETIN 240: CONTRIBUTIONS FROM THE MUSEUM OF HISTORY AND TECHNOLOGY 



