MACHINE PERFORMANCE CURVE 



109 



k c is the centre of pressure coefficient, to which no corrections 

 need be applied. 



V is the speed of the machine in miles per hour in standard 

 density air. 



P is the effective horse-power required to maintain horizontal 

 flight at V miles per hour in standard density air. 



Now write down the numerical values of W, S, k^ max , R, ^ 

 /, and /'. 



Then work out and write down the numerical values of 



IQ6W Ra 



a = , p = 2, 



S/ r max I o 



7 = - and S = . 

 c c 



Then construct a table in the following form : 



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 Second Method. 



Third Method. 



W is the total weight of the machine in pounds. 



S is the total area of the wings in square feet (including S'). 



S' is the area in square feet of that part of the wings which 



