112 SMITHsoXI \.\ CONTRIBUTIONS TO KNOWLEDGE VOL. 27 



rel of the cylinder should be as thin as possible, thai no protective jacketing 

 should be used, and thai the valve motion should be of the simplest description. 

 To obtaining the greatesl lightness consistent with indispensable power, every- 

 thing else was subordinated; and hence, all expectation of ordinary economical 

 efficiency had to be abandoned at the outset. 



tt was only after long trials in other directions that Mr. Langley intro- 

 duced the aeolipile device, which for the first time provided sufficient heat. Even 

 in the aeolipile, however, it was apparent that nothing short of the most com- 

 plete combustion accompanied by the highest possible temperature of the flame 

 would be sufficient for the extreme demand. To secure this result under all 

 conditions of wind and weather, with the aerodrome at rest and in motion, re- 

 quired Hie long scries of experiments that are given in another chapter. In 

 respecl to the generation of heat, then, it is probable that it would be difficult to 

 exceed the performance of the final type of burner in practical work, but in the 

 utilization of this heal in the boiler, as well as in the utilization of the steam 

 there generated, the waste was so great as to be prohibitive under ordinary 

 conditions. Rut this was not ordinary work, and the simplest protection against 

 radiation from boiler, separator, and engine could not well be used. 



The framework of the aerodrome is made of thin steel tubes, the main or 

 midrod extending the whole length of the machine and carrying the attach- 

 ments to which the wings are fastened. Suspended from this midrod by rigid 

 connections is a skeleton hull of steel tubing, shaped somewhat like the frame- 

 work of a boat, from which, directly abeam of the engines, arms are run out 

 like the outriggers of a rowboat for carrying the propellers. Within this cen- 

 tral hull are placed the aeolipile, the boiler, and the engine, which with their 

 auxiliary parts, the pump and the separator, constitute the entire power-gener- 

 ating apparatus. 



The aeolipile consists of four essential parts: the spherical air chamber con- 

 taining the supply of compressed air by which the gasoline in the reservoir 

 tank is forced into (he burner; the reservoir tank containing the gasoline that 

 is to be used as a fuel; the gas generator wherein Ihe liquid gasoline is heated 

 and converted into gas; and the burners where it is finally utilized to heat the 

 boilers. 



The air chamber D, Dale 25, is a spherical vessel 120 mm. in diameter, lo- 

 cated al the extreme front end of the hull. It is made of copper 0.25 mm. thick 

 and has two openings. The front opening has a copper pipe 1 cm. outside diam- 

 eter, lo which Ihe air pump for charging tin 1 chamber is connected. From the 

 back a copper pipe 5 mm. outside diameter extends to the top of the gasoline 

 reservoir. 



This reservoir, shown al 7, Plate 25, is also a light, hollow sphere 120 mm. 

 in diameter; both I his and the air chamber being made by soldering hemispheres 



