text: airplane. Density altitude will determine 
  the true airspeed at takeoff and can affect 
  the 
  the 
  takeoff acceleration by altering 
  powerplant thrust. The effect of tempeta- 
  ture alone is important 
  in the case of the 
  turbine powered aircraft since inlet air tem- 
  perature will affect powerplant thrust. 
  Ic 
  should be noted that a typical turbojet ait- 
  plane may he approximately twice as sensi- 
  tive to density altitude and five to ten times 
  as sensitive to temperature as a representa- 
  cive reciprocating engine powered airplane. 
  (4) Specific humidity must be accounted 
  for in the case of the reciprocating engine 
  powered airplane. A high water vapor 
  content in the air will cause a definite reduc- 
  tion in takeoff power and takeoff acceler- 
  ation. 
  
  (5) The runluay condition will deserve con- 
  sideration when the takeoff acceleration is 
  basically low. The runway slope must be 
  compared carefully with 
  the surface winds 
  because ordinary values of runway slope will 
  usually favor choice of the runway with 
  headwind and upslope rather than down- 
  slope and tailwind. 
  The surface condition 
  of the runway has little bearing on takeoff 
  distance as long as the runway 
  is a hard 
  surface. 