RIGID STABLE AEROPLANES. 



383 



The scale drawing (Fig. 1) shows in every detail the 

 method of combining two reverse curves so that they shall 

 be permanently stable, not only longitudinally but trans- 

 versely. It shows how rigidity of form is maintained 

 without the use of diagonal ties of any sort. It shows how 

 any number of sections may be united to support any weight. 

 It shows that the limit of weight that the ordinary mono- 

 plane or bi-plane soon reaches, is easily passed by the 

 substitution of arithmetical for geometrical progression in 

 the proportions of the lifting areas. It shows the futility 

 of applying reverse curves to the ordinary flying machines 

 if they are rigidly attached thereto, because the combined 

 inertia of motor, passengers, heavy struts, stays, etc., 

 effectually masks and prevents the instant action of the 

 light reverse curves in automatically adjusting themselves 

 to every gust and tremor in the air. 



The type of motor most suitable for driving rigid stable 

 aeroplanes is the two-stroke spring engine (Fig. 2 a, b). This 



C 5troke S/>rt/uj Engine 



4- J I V 



Fig. 2 a. 



