NO. 3 LANULEY MEMOIB ON MECHANICAL FLIGHT 55 



As soon as these engines were completed, in February, 1893, a test was 

 made of one of the cylinders, steam being supplied from the boiler of the shop- 

 engine. The experiments were made with the Prony brake, and showed thai at 

 a speed of 1000 revolutions per minute, the power developed from a single cylin- 

 der was 0.208 H. P., with a mean effective pressure in the cylinder of only about 

 21 pounds per square inch of piston area, allowing a loss of 25 per cent for the 

 internal resistance of the engine. This pressure was so much less than should 

 have been obtained with the steam pressure used, that it now seems evident that 

 the steam passages and ports were too small to admit and exhaust the steam with 

 sufficient rapidity to do the work with the same efficiency that is obtained in 

 common practice. This, however, was not immediately recognized. The piston 

 speed at 1000 R. P. M. was 328 feet per minute, at which speed the steam al a 

 pressure of 80 pounds should have been able to follow up the piston and main- 

 tain almost, if not quite, full boiler pressure to the point of cut-off, but it did 

 not do so. 



The problem of generating steam was much more difficult and required a long 

 and tedious series of experiments, which consumed the greater part of the year 

 before any considerable degree of success had been attained. In the course of 

 these experiments many unexpected difficulties were encountered, which neces- 

 sitated the construction of special forms of apparatus, which will be described 

 at the proper point. Numerous features of construction, which seemed to be of 

 value when first conceived, but which proved useless when rigorously tested, will 

 be noted here, whenever a knowledge of their valuelessness may seem to be of 

 advantage to the reader. 



The boiler was necessarily developed simultaneously with the development 

 of the heating apparatus, and in the following pages, as far as possible, they will 

 be treated together ; but often for the sake of clearness and to avoid repetition, 

 separate treatment will be necessary. 



At the beginning of these experiments, there was much doubt as to whether 

 alcohol or gasoline would be found most suitable for the immediate purpose. 

 An alcohol burner bad been used in connection with the earliest aerodrome, No. 

 0, but from the results obtained with it at that time, there seemed to be little 

 reason to hope for success with it. It is to be premised that the problem, which 

 at first seemed insoluble, was no less than to produce steam for something like 

 1 H. P. by a fire-grate, which should occupy only a few cubic inches (about the 

 size of a clenched hand) and weigh but a few ounces. Tt had to be attacked, 

 however, and as alcohol offered the great advantage of high calorific properties 

 with freedom from all danger of explosion, it was at first used. 



Early in 189.1, it occurred to me to modify the burner so as to make it essen- 

 tially an aeolipile. and in April of that year the first experimental aeolipile model 

 shown at A (Plate 12) was made. It was very small and intended for the dem- 



