FLYING-MACHINE MEMORANDA. 73 



only about 4 feet lonf,' brini^'S the centre of gravity very far aft. 

 It is found tliat if more tlian 2-')'"/ of the area is in advance of the 

 centre of gravity the models turn up and wreck ensues as a matter 

 of course. One remarkable experiment repeatedly made, for w liich 

 the writer cannot account is that Fig. 7, whicli is (;alled F morlel, 



pelled IS feet by stretching tlie crossbow \'2 inches ; and another 

 model called C, weighing G-,') ounces and having an area of I'yQ 

 square inches is propelled 20 feet by tlie same motive power, the 

 speed of the latter being obviously slower : it looks as if large 



centre of effort there is no tendency to swerve, the turnin; 

 down of the models is entirely due to the distance of the 

 of gravity from the forward edge of the body plane. 



On looking into the relative positions of the centres of ; 

 and effort of the three most successful machine-, yet m 

 appears that the percentage of the areas in advance of tlie 



' ' ' 4SbandL 19-3:/ 



L>1 band H.J.K. ... 20-0/ 



4S band single screw 23-.3 / 



Tlie.-,e positions were arrived at by experience gained by rt 

 wrecks when groping in comparative darkness. 



deeply interesting point in all the experiments. It is ol 

 that tlie successful flyers maintain a horizontal position d 



l'\"l Mild not tilted up forward iit anything approaching the 



of 14'8 srpiare fe( 



