MACHINE PERFORMANCE CURVE 33 



D/ = T' - D 2 ' 

 and D 2 ' = j-^ 



leading to W/ + T'^ = L'f/' - ck c + ^"^1 . (4) 



= ^ X -00237 7T/ A^.^^'V^' + 2) (6) 



2 4\I2/ 



P' T' T ' W 



Now let P/ = -, T/ - :L, L/ = -, and W, = _. 



(7 G (7 CT 



Then the above six equations become the following : 



co 



L/ = -oo2 3 7*JS - S' + (i + ^) 2 S'](i-467V') 2 . (3') 

 W,/ + T^ = L//' - * e + =] (4') 



(5') 



Now comparing these six equations with the six equations of 

 the Fourth Method, we see that they are the same except that 

 P/, V, T/, b', L/, and W 1 have been written in place of 

 P, V, T, b, L, and W. Therefore the solution of our present 

 six equations can be got by making this substitution in equations 

 (V) and (P) of the Fourth Method, page 30. We therefore. 

 have for flight at an altitude 



V = 



L/D 



remembering that 0, <, and ^ have the same values as before 



Comparing these two equations with equations (V) and (P) 

 of page 30 we have 



3 



