-62- 450  400  350  300  250  200  150  100  18  20  22  24  26  28  R.P.M.  2300  FULL THROTTLE  HORSE POWER  i500 ft. ALTITUDE PERFORMANCE  HORSE .POWER VS. MANIFOLD PRESSURE  WRIGHT AERO ENGINE  MODEL R-975-28  Fig.  XX  30  32  31  36  38  ABSOLUTE MANIFOLD PHESS1J’flE IN . HG 