text: where 
  
  S= distance 
  V= velocity, 
  a= acceleration 
  
  A change in gross weight will change the 
  net accelerating force, Fn, and change the 
  mass, M, which is being accelerated. If the 
  airplane has a relatively high thrust-to-weight 
  ratio, the change in the net accelerating force 
  is slight and the principal effect on accelera- 
  tion is due to the change in mass. 
  
  ;’ con&&‘(I) 
  
  applies to some known takeoff 
  distance, Si, which was common to 
  some original takeoff velocity, Vi, and 
  acceleration, ai. 
  
  condition (2) applies to some new takeoff 
  distance, Sa, which is the result of some 
  different value of takeoff velocity, Vs, or 
  acceleration, aa. 
  
  To evaluate the effect of gross weight on 
  
  takeoff distance, the following 
  are used : 
  
  relationship 
  
  the effect of weight on takeoff velocity is 
  
  With xhis basic relationship, the effect of the 
  many variables on takeoff ‘distance can be 
  approximated. 
  
  The effect of gross weight on takeoff distance is 
  large and proper consideration of this 
  item 
  must be made in predicting takeoff distance. 
  Increased gross weight can be considered to 
  produce a threefold effect on takeoff perform- 
  ance: (1) increased takeoff velocity, (2) greater 