134 SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE VOL. It 



The perfected launching apparatus which had been used for the steam- 

 driven models Nos. 5 and 6 (described in Part I, Chapter X) had proved most 

 satisfactory and reliable, but when the designs were made for a launching ap- 

 paratus for the large machine it was found that an exact duplication of the 

 plan of the small one involved serious difficulties in connection with the con- 

 struction of the house-boat, owing to the very considerable weight and size of 

 the turn-table necessary to permit the aerodrome to be launched in any desired 

 direction, regardless of the direction in which the house-boat might be pointing 

 under the influence of the wind and tide. A new design was accordingly made 

 for a launching apparatus in which the launching car was to run on a track 

 mounted directly on the turn-table, the launching car supporting the aerodrome 

 from underneath, instead of being mounted in an inverted position on an over- 

 head track with the aerodrome depending from it. 



From the previous description of the launching apparatus, it will be re- 

 called that, in order to provide that the aerodrome should drop slightly at the 

 moment of its release from the car, and thereby avoid all danger of entangle- 

 ment, the speed of the launching car at the point at which the aerodrome was re- 

 leased was purposely made less than the " soaring speed " of the aerodrome. 

 Having this feature in mind, when designing the " underneath " launching ap- 

 paratus, it was recognized that the danger of the aerodrome becoming entan- 

 gled with this form of apparatus could be avoided by making the launching speed 

 greater than the velocity which it would be necessary for the aerodrome to 

 have in order to soar, provided the balancing was correct ami the aerodrome /lid 

 soar. Nevertheless, it was deemed unwise to put too much dependence on the 

 empirical calculations from which the balancing of the large aerodrome would 

 necessarily be determined, and, therefore, some means seemed necessary for 

 causing the launching car to drop out of the way immediately upon releasing 

 the aerodrome. In the new design, more completely described below, in Chapter 

 IV, this was accomplished by so arranging a portion of the front end of the track 

 that, at the moment the launching car released the aerodrome, it dropped like a 

 disappearing gun carriage, leaving the aerodrome free in the air with no pos- 

 sibility of becoming entangled, provided the aerodrome itself did not drop more 

 rapidly than an anule of 15 degrees. 



A small working model of this launching apparatus, one-eighth the linear 

 dimensions of that which would be necessary for the large aerodrome, was first 

 designed and constructed in the shop, the small one-eighth-size model of the 

 large aerodrome being launched from it into a sheet stretched in front of it to 

 act as a buffer. When it was found to work very satisfactorily, a large one, 

 twice this size, was immediately built for use with the steam-driven models Nos. 

 5 and 6. 



