100 SMITHSONIAN CONTRIBUTIONS In KNOWLEDGE vol.. 27 



guy-wires caught on the launching car, and threw the aerodrome immediately 

 into the water with but little damage. 



On the same day No. 5 was launched. The theoretical CP-CG was nomi- 

 nally 0, but, for the reasons stated in the footnote on p. 99, was really something 

 positive, that is to say, the CP was really somewhat in advance of the CG; in- 

 clination of midrod less than a ( = 20°). The aerodrome under these circum- 

 stances, while keeping its head up, at first fell rapidly, yet seemed about to rise 

 just as it struck the water, conveying the idea that if the launching had been 

 made with a greater initial velocity it would have risen and cleared the water. 

 The wings visibly pocketed, however, and it was clear that some better dispo- 

 sition must still be made for them. The flight was 3J seconds. 



No. 5 was tried again on the same day with larger wings, whose area was 40 

 square feet. These wings, though stirrer, pocketed a little. a = 20° as before. It 

 flew rapidly, and at first horizontally, to a distance of 100 feet or more against 

 a five-mile breeze. It then turned abruptly round through ISO , at first falling 

 (from loss of headway), then distinctly rising, and at the same time throwing 

 its head up until it reached an angle of nearly 60 : with the vertical, when it fell 

 backward after a flight of between (5 and 7 seconds. The wings were evidently 

 not yet strong enough to resist flexure. 



November 21. No. 5, in nearly the same condition as before. Two extra 

 springs had been placed on the launching car, in order to give the aerodrome a 

 greater initial velocity than before. Everything appeared favorable, but as it 

 left the launching track a piece flew out of the port propeller, in spite of which 

 the aerodrome, after dropping 5 feet, rose bodily at an angle of 45° and fell 

 backward into the water (time, 5 seconds). 



Another trial was made the same day with the same aerodrome, under sim- 

 ilar conditions, except that the angle of inclination (a) was reduced to 7°. It 

 now, with all the other circumstances of launching like those immediately be- 

 fore, behaved entirely differently, plunging head downward into the water at 

 a distance of 30 feet. Once more it was shown beyond dispute that the wings 

 must somehow be made even stiffer. 



December 8. Another trial was undertaken with No. 5, the CG being 10 cm. 

 in front of the CP at rest. The root angle of the wings was 18°, tip angle 27 , 

 elevation of midrod 1 in 24. The other changes made since the previous trial 

 consisted chiefly in the increased weight due to the longer and stronger frames 

 and shafts that were made to carry 100 cm. propellers. The flight obtained was 

 so short thai it was as unsatisfactory as before. 



The aerodrome rose in the air after leaving the launching apparatus, and 

 then slid back into the water in the plane of its own wings. On the first trial, it 

 struck the boat, and was slightly injured; on the second, with root angle of 



