AIR PERFORMANCE 137 



Then the cruising distance in miles is 



x v't, 



but again, to secure the full mileage, the machine must be flown 

 at a series of air speeds 



as W gradually decreases from W to W. 



If the cruising revolutions are required, see Chapter V., 

 page 59. 



Examples. For numerical examples illustrating the methods 

 of this Chapter, see Chapter XIX., page 164, and Chapter 

 XXII., page 189, etc. 



Theory. For theoretical explanations see Chapter V., 

 page 35. 



