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SMITHSONIAN CONTRIBUTIONS TO KNOWLEDGE 



VOL. 



longitudinal side members were piston rods, on which were mounted leather-cup 

 pistons, which co-acted with buffer cylinders fixed at the extreme front of the 

 trad to absorb the Mow when the car reached them at the end of its travel. 

 The car was supported on each side by means of four hangers (Figs. 4 and 5) 

 which rallied grooved wheels having hall-bearings and running on a steel track 

 consisting of flat plates fastened on the side of the timbers of the launching 

 track. On the extreme lower point of these hangers were small guide pulleys, 

 so placed as to be just below and out of contact with a guard rail on the side 

 of the launching track, thus preventing any possibility of the launching car be 

 ing raised from the track either during its forward motion or by a side wind 

 striking underneath the wings. 



On the large launching car the arrangement of the struts against which the 

 bearing points of the frame were tightly drawn by the clutch was similar in all 

 respects to that used on the model car, there being only slight differences in 

 details. The details of the uprights on which the bearing points of the aero- 

 drome frame rested are clearly shown in Figs. 6, 7, 8, and 9 of Plate 40. From 

 the photographs (Plate 41, Figs. 1, 2, and 3) which show the large frame 

 mounted on the launching car, the general arrangement of the struts and the 

 clutch-hook can be readily seen; and from Plate 42, Figs. 1, 2, and 3, which show- 

 in detail most of the important features of the clutch-post and its clutch, a very 

 good idea of the size of the different parts may be had by observing that the 

 distance from the fulcrum of each half of the hook to the pin by which it was 

 connected through the universal joint to the vertical rods is five inches. As 

 previously stated, this clutch hook gripped the lower pyramid and pulled the 

 bearing points of the frame firmly against the forward and rear stmts of the 

 launching car, and in launching the aerodrome the triggers arranged on the 

 bottom of the car, which at the proper time pull on the vertical rods and therebj 

 force the two halves of the clutch-hook apart, are so arranged that they strike 

 a cross beam at the front end of the track one inch before the triggers, which 

 keep the struts from being pulled down by their springs, which tend to fold 

 Hi, mii up and force them down against the car. The triggers, which prevent the 

 struts from being folded down, strike a cross-beam in the track one foot before 

 the buffer pistons on the end of the car begin to enter the buffer cylinders at 

 the end of the track, ami, consequently, one foot before the folding prop, which 

 supports the front end of the track, is knocked out by the car striking a special 

 trigger which allows this folding prop to swin.n forward when the front end of 

 the track folds down to insure that the aerodrome will not become entangled 

 with the car, even though the aerodrome be not quite u]> to soaring speed at the 

 moment of launching. The manner in which this front end of the track folds 

 down can be very readily seen by comparing Plate 4.". with Plate 95 of Chapter 

 XII, the former showing the front end of the track in horizontal position, with 



