NO. 3 LANGLEY MEMOIB ON MECHANICAL PLIGHT <',."> 



In addition to these radical changes many important improvements were 

 made in the different parts. Internal compartments were built in the separa- 

 tor, so that even if the water was displaced by the pitching of the aerodrome, it 

 could still perform its functions properly The pump was provided with a ratchet, 

 so that it could be worked by hand after the burners were lighted, and before 

 enough steam had been raised to enable the engine to run it. An active circu- 

 lation was thus maintained in the coils of the boiler as soon as the burner was 

 lighted and before the engine was started, which prevented the tubing from be- 

 ing burnt out, as had frequently happened previously. The wing construction 

 was also improved aud many other changes were introduced, which will be treated 

 separately. 



In the meantime, No. 4, which had been damaged in the attempted launching 

 in November, 1893, was strengthened and prepared for another trial which took 

 place in January, 1894. 



By the end of the first week in February, the engine of No. 5 was ready for 

 trial, and with a boiler pressure of about 80 pounds per square inch, apparently 

 developed 0.56 H. P. on the Prony brake, when making 800 revolutions per min- 

 ute. To accomplish this called for such good distribution of steam in the cyl- 

 inder, that it is doubtful if the power could be exceeded at that speed and 

 pressure. 



It was, however, apparent that it was desirable to have a boiler capable of 

 supplying steam for at least one horse-power, and that in order to do this, there 

 must be an improvement in the aeolipiles. The problem consisted in arranging 

 to evaporate more than 500 cu. cm., and in fact as nearly as possible 1000 cu. 

 cm. (61 cu. in.) of water per minute, and, since from 200 to 300 cu. cm. per 

 minute had already been evaporated, this was not regarded as impossible of ac- 

 complishment. The theoretical advantages of gasoline had for a long time been 

 recognized, as well as the very practical advantage possessed by it of keeping 

 lighted in a breeze, aud several attempts had been made during the latter part 

 of the previous year to construct a suitable burner for use with it. These had 

 not been very successful; but in view of the increasing demand for a flame of 

 greater efficiency than that of the alcohol aeolipiles, it was decided to resume the 

 experiments with it. 



Accordingly, a gasoline evaporator was tried, consisting in the first ex- 

 periment of a gasoline tank with nine flues, through which steam was passed. 

 A flow of steam gave a rapid evaporation of gasoline when the pressure did not 

 exceed 5 pounds. The chief difficulty with the burner employed was that the 

 supply of gasoline gas would rise and fall as the steam rose and fell, conditions 

 just the opposite of what was really desired. On the other hand, it was thought 

 that this gasoline tank would form a real condenser for the steam, so that a por- 



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