NO. 3 LANGLEY MEMOIR ON MECHANICAL FLIGHT 37 



depended upon to supply the steam that the compound engines would require; 

 but after the whole was completed, the weight, if nothing else, was prohibitory. 



I had gone on from one thing to another, adding- a little here and a little 

 there, strengthening this part and that, until when the hull was finally completed 

 with the engines and boilers in place, ready for the application of the wings, the 

 weight of the whole was found (allowing 7 pounds for the weight of the wings 

 and tail) to be almost exactly 45 pounds, and nearly 52 pounds with fuel and 

 water. To this excessive weight would have to he added that of the propellers, 

 and as the wings would necessarily have to be made very large in order to carry 

 the machine, and as the difficulties of launching had still to be met, nothing was 

 attempted in the way of field trials, and with great disappointment the decision 

 was made in May, 1892 (wisely, as it subsequently appeared) to proceed no 

 further with this special apparatus. 



However, inasmuch as this aerodrome with its engines and boilers had been 

 completed at considerable expense, it was decided to use the apparatus as far 

 as it might be practicable, in order to learn what must be done to secure a 

 greater amount of success in the future. The fundamental trouble was to get 

 heat. In the first place there was trouble with the burners, for it seemed to be 

 impossible to get one that would vaporize the gasoline in sufficient quantity to 

 do the work, and various forms were successively tried. 



All of the early part of 1892 was passed in trying to get the boilers to work 

 at a steam pressure of 100 pounds per square inch. On account of the defects 

 in the tubes and elsewhere this required much patient labor. The writer, even 

 thus early, devised a plan of using a sort of aeolipile, which should actuate its 

 own blast, but this had to be abandoned on account of the fact that the pear- 

 shaped receivers would not stand the heat. This necessitated a number of ex- 

 periments in the distillation of gas, in the course of which there was trouble 

 with the pumps, and a continual series of breakages and leakages, so that the 

 middle of April came before I had secured any further satisfaction than to dem- 

 onstrate that possibly the boilers might have a capacity sufficient for the work 

 laid out for them to do; but subsequent experiments showed that even in this 

 I was mistaken, for it was only after additional jets had been put in between the 

 coils that I succeeded in getting an effective horse-power of 0.43 out of the 

 combination. 



Finally, on the 14th of April, after having reduced the capacity of the pumps 

 to the dimensions given above (for the stroke was originally 1.25 inch) I obtained 

 the development of 1 full horse-power by the engine for 41 seconds, with a steam 

 pressure of 100 pounds per square inch, and a rate of revolution of 720 per 

 minute. But at the end of this brief period, the shafts sprung and the worm 

 was thrown out of gear. 



