A TYPICAL MACHINE 



197 



These are plotted on page 193. 



Times to all Altitudes. The plotting of rate of climb on 

 altitude is (at least up to 10,500 feet) a close approximation to 

 the straight line which cuts the ground level line at 600 feet per 

 minute and the "no climb" line at 13,600 feet. 



Therefore the time t in minutes to the height a (up to 

 10,500 feet at least) is given by 



'33-, 



logio /-uN 

 \ 1 - a/ 



where c = 600 and a x = 13,600. 



These times are plotted on page 193. 



Best Altitude for Cruising Against a Twenty Mile Wind. 



First we must find the relative consumption a and also the 



quantity 



_ i for a range of speeds and altitudes. 

 = -161. 



