MACHINE PERFORMANCE CURVE 



Next fill up the X column as shown and the L/D and k c 

 columns as explained in the definitions of L/D and k c given 

 above. Then work out the columns in succession. 



The last two columns then give the values of V and P, which 

 can be used to plot the machine performance curve for standard 

 density air under the assumptions of the Fourth Method. 



The Machine Performance Curve at an Altitude. First 

 draw up a table in the following form, allowing for ten horizontal 

 lines of figures : 



V. 



p. 



P'. 



This table can, of course, be drawn up as an extension of the 

 table used to find the machine performance curve in standard 

 density air, in which case the first two columns are already filled 

 up. If, however, the table is a separate one, the first thing to 

 do is to fill up the first two columns by copying out the last two 

 columns of the previous table. 



Now fill up the last two columns with the aid of the formulae 



V = X and P' = 



where <j is found for the altitude under consideration by reference 

 to the curve on page 104. 



The above procedure is the same whichever method has been 

 used to find the machine performance curve for standard density 

 air. 



Examples. For numerical examples illustrating the methods 

 of this Chapter, see Chapter XVIIL, page 155, and Chapter 

 XXII., pages 1 88 and 194. 



Theory. For theoretical explanations see Chapter IV., page 

 21. 



