464 POPULAR SCIENCE MONTHLY 



Everything connected with the work was expedited as much as 

 possible with the expectation of being able to have the first trial flight 

 before the close of 1899, and time and money had been spent on the 

 aerodrome, which was ready, except for its engine, when the time for 

 the delivery of this arrived. But now the builder proved unable to 

 complete his contract, and, after months of delay, it was necessary to 

 decrease the force at work on the machine proper and its launching 

 appliances until some assurance could be had of the final success of 

 the engine. During the spring and summer of 1899, while these 

 delays were being experienced in procuring suitable engines, former 

 experiments on superposed wing surfaces were continued, time was 

 found for overhauling the two steam-driven models which had been 

 used in 1896, and the small house boat was rebuilt so that further 

 tests of these small machines might be made in order to study the 

 effect of various changes in the balancing and the steering, equilibrium 

 preserving and sustaining appliances, and the months of June, July 

 and a portion of August were spent in actual tests of these machines 

 in free flight. 



A new launching apparatus following the general plan of the 

 former overhead one, but with the track underneath it, was built for 

 the models, and it was used most successfully in these experiments, 

 more than a dozen flights in succession being made with it, while in 

 every case it worked without delay or accident. As soon as these 

 tests with the models on this underneath launching apparatus were 

 completed, that for the large machine was built as an exact duplicate, 

 except for the enlargement, and with some natural confidence that what 

 had worked so perfectly on a small scale would work fairly on a large 

 one. 



It was recognized from the very beginning that it would be desir- 

 able in a large machine to use " superposed " sustaining surfaces (that 

 is, with one wing above another) on account of their superiority so 

 far as the relation of strength to weight is concerned, and from their 

 independence of guy wiring; and two sets of superposed sustaining 

 surfaces of different patterns were built and experimented with in the 

 early tests. These surfaces proved, on the whole, inferior in lifting 

 power, though among compensating advantages are the strength of a 

 " bridge " construction which dispenses with guy wires coming up from 

 below, which, in fact, later were the cause of disaster in the launching. 



It was finally decided to follow what experiment had shown to be 

 successful, and to construct the sustaining surfaces for the large 

 machine after the " single-tier " plan. This proved to be no easy 

 task, since in the construction of the surfaces for the small machines 

 the main and cross ribs of the framework had been made solid, and, 

 after steaming, bent and dried to the proper curvature, while it was 



