text: NAVWEPS 00-801-80 
  AIRPLANE PERFORMANCE 
  
  the airplane at any 
  instant during takeoff roll is a function of the 
  net accelerating force and the airplane mass. 
  From Newton’s second law of motion: 
  
  The acceleration of  The total retarding for& on the aircraft is 
  
  the sum of drag and rolling 
  and, for the majority of configurations, this 
  sum is nearly Constant or changes only slightly 
  during the takeoff roll. The net accelerating 
  force is then the difference between the power- 
  plant thrust and the total retarding force, 
  
  friction (D+F) 
  
  where 
  Fn=T-D-F 
  a=acceleration,~fr. per set 
  
  Fn- net accelerating force, 
  lbs. 
  W=weight, 
  g? gravitational accelerat 
  
  =32.17 ft. per sec.*
  
  M= mass, slugb 
  
  = WE 
  
  The riet aicelerating 
  fdrce on ‘the airplane, 
  F,, is the net of thiust, T, drag, D, and rolling 
  friction, F. Thus, the acceleration -at any 
  instant during takeoff roll is: 
  
  a=&T-D-F) 