NO. 3 LANGLEY MEMOIH OH MECHANICAL FLIGHT 113 



of copper together at their circumferences. There are three openings in the 

 reservoir tank; two at the top and one at the bottom. One of those at the top 

 serves for the admission of the 5-nnn. pipe bringing compressed air from the 

 air chamber; the other is connected with a pipe 1 cm. in diameter, through winch 

 gasoline is supplied to the tank, and which is closed by a simple ping at the top. 

 The hole in the bottom serves as the outlet for the gasoline to the burners. Close 

 to the bottom of the tank there is placed a small needle valve, which serves to 

 regulate the flow of oil, for, were the pipe left open, the compressed air would 

 force the oil out with such rapidity that the burners would be flooded and the 

 intensity of the flame impaired. The construction of this valve is clearly shown 

 in Plate 26A. It consists of a brass shell having one end (a) soldered to the bot- 

 tom of the tank. The needle enters through a stuffing box whose gland is held 

 by two small screws. The stem of the needle is threaded and engages in a thread 

 cut in the body of the casting and is operated by a fine wire on the outside. It 

 will readily be seen that this device affords a means of making a very accurate 

 adjustment of the flow of the liquid to the burners. 



After leaving the needle valve the gasoline flows along the pipe 8, Plate 25, 

 until it reaches the evaporating coil, N. In order to subject the oil to as large 

 a heating surface as possible, in comparison with the sectional area through 

 winch it is flowing, the pipe, which left the needle valve with a diameter of 6 mm. 

 soon contracted to 5 mm., is here flattened to a width of 7 mm. and a thickness 

 of 2 mm. There are seven complete turns of this flattened tubing coiled to an out- 

 side diameter of 30 mm. At the end of the seventh coil the pipe is enlarged to a 

 diameter of 1 cm. and two coils of this size are added, the inside diameter being 

 the same as that of the flattened coil. This enlarged portion serves as a sort of 

 expansion chamber for the complete gasification of the gasoline, which is then 

 led back through a turn of the enlarged pipe, beneath the coils and to the front. 

 At the front end of the coil a small branch is led off, forming a " bleeder," 

 which takes sufficient gas to supply the burner by which the coil is heated, the 

 products of whose combustion pass into and between the coils of the boiler 

 like those of the regular heating burners. The gas pipe rises in front of the coil 

 and by a T connection branches to the two burners that are placed in front of 

 the coils of the boiler. These burner pipes are 5 mm. in diameter and enter 

 sheet-iron hoods forming regular burners of the Bunsen type, which are fully 

 shown in all their details in the accompanying engraving, Plate 26. The pipe is 

 plugged at the end, and a hole 0.9 mm. in diameter drilled for the nipple of the 

 burner in front of the coil where the water first enters from the separator, and 

 0.85 mm. for the one in front of the return coil. The face of the burner shell 

 stands exactly central with and 41 mm. in front of the coils. 1 



•Very exact accuracy in these minute details is indispensable to the efficient working of the 

 engines. 



