EXPERIMENTS WITH THK LANOLEY AKRoDKoMK. 117 



of ]\rr. TNfnnly. These engines wer(> to he of nearly double (lie power 

 first estimated and of little more weight, hut this increased jjowcr and 

 the strain caused by it demanded a renewal of the frame as first built, 

 in a stronger and conseciiiently in a li(>avier form, and tlie following 

 sixteen months were spent in such a reconstruction simultaneously 

 with the work on the engines. 



The flying weight of the machine complete, with that of the 

 aeronaut.' was 8;iO j)ounds: its sustaining sui-face, 1,040 srpiare feet. 

 It therefore was provided with slight!}^ greater sustaining surface 

 and materially gi-eater relative horsepower than the model subse- 

 quently described which flew successfully. The brake horsepower 

 of the engine was 52; the engine itself, Avithout cooling water, or 

 fuel, weighed approximately 1 kilogram to the horsepower. The en- 

 tire power plant, including cooling water, carburetor, battery, etc.. 

 weighed materially less than 5 pounds to the horsepower. Engines 

 for both the large machine and the quarter-size model were completed 

 before the close of 1901, and they were immediately put in their 

 respective frames and tests of them and their power-transmission 

 appliances were begun. 



It is well here to call attention to the fact that although an engine 

 may develop sufficient ])Ower for the allotted weight, yet it is not at 

 iill certain that it will be suitable for use on a machine which is 

 necessarily as light as one for traversing tlie air, for it would be 

 impossible to use, for instance, a single cjdinder gasoline engine in a 

 flying machine unless it had connected to it prohibitively heavy fly- 

 wheels. These facts being recognized, the engines built in the Smith- 

 sonian shops were provided w^ith five cylinders, and it was found 

 upon test that the turning effect received from them was most uniform, 

 and that, by suitable balancing of rotating and reci]:)rocaling [)arts, 

 they could be made to work so that there was practically no vibration, 

 even when used in the very light frames of the aerodromes. 



The engine is not all the apparatus connected with the development 

 and delivery of power, for obviously (here must l)e shafts, bearings, 

 and in the present case there were also gears; and all of these parts 

 must necessarily be phenomenally light, while all of the materials 

 must be capable of withstanding repeated and constant strains fur 

 bej'ond their elastic limit. It is also evident to anyone having famil- 

 iarity with such constructions that it is most difficult to keep the 

 various bearings, shafts, gears, etc.. in j^rojK'r alignment without 

 adding excessive weight, and also that when these various parts once 

 get out of alignment Avhen subject to strain, the disasters which are 

 caused render them unfit for further use. 



The engines themselves were successful!}^ completed before the close 

 of 1901, and were of much more power than those originally designed: 

 but nearly a year and a half had been spent not only in their comple- 



