248 SYMPOSIUM ON AERONAUTICS. 



(a) Single side-gusts were shown to produce modern side- 

 slipping, insignificant roll, and moderate yaw. It was seen that the 

 yaw was into the relative wind so that the displacement of the ma- 

 chine in space was toward the gust despite the side-slipping. 



(b) Oscillatory side-gusts were shown to be a common condi- 

 tion of flight, to produce moderate side-slipping and yawing, but 

 insignificant rolling. The path of the center of gravity proved 

 to be sinusoidal, so far as the forced oscillation was concerned, and 

 of amplitude about 2 or 3 times the amplitude of the gust. 



(c) Yawing gusts were found to induce a good deal of side- 

 slipping, but did not appear to be serious. The roll was very small. 



(d) Rolling gusts were seen to put the machine into a spiral 

 dive, and thus to cause a real danger unless the motion were checked 

 promptly by the pilot. 



6. Constrained Machines. — A device to keep the aeroplane on its 

 course or to prevent rolling made the previously unstable machine 

 stable. Such a device might be important to reduce the liability 

 to the spiral dive in rolling gusts provided such gusts were common 

 phenomena in flying weather. 



7. Other Methods of Treatment. — The Bryan-Bordetsky method 

 of initial motions and Bromwich's new method of finding the solu- 

 tion for a disturbed state without calculating the constants of integra- 

 tion were briefly compared with my system of analysis. 



Massachusetts Institute of Technology, 

 Cambridge, AIass. 



