122 AEROPLANE PERFORMANCE CALCULATIONS 



The method is only approximate, even if the P curve is got 

 from the Fourth Method. 



Second Approximation. This approximation, though con- 

 siderably more laborious than the first, gives results differing 

 appreciably from it only in the case of machines which are really 

 very strong climbers : its use should therefore be limited to such 

 cases. 



Construct a table in the following form, providing for say 

 half a dozen horizontal lines of figures : 



- 

 1 + 



i, 



& 



U 



^ft 



a, o. 

 CM !CU 

 I 



